WO2025175218A1

WO2025175218A1 - Fluid pressure oscillator driven dynamic pressure navigational assistance device for a catheter

Info

Publication number: WO2025175218A1
Application number: PCT/US2025/016103
Authority: WO
Inventors: Stephen Porter
Original assignee: Stryker European Operations Ltd; Stryker Corp
Current assignee: Stryker European Operations Ltd; Stryker Corp
Priority date: 2024-02-16
Filing date: 2025-02-14
Publication date: 2025-08-21
Anticipated expiration: 2026-08-16

Abstract

A navigation assistance device (16) for use with an outer elongate intravascular device (12) having a device lumen and an inner elongate intravascular device disposed within the device lumen. The navigation assistance device (16) comprises a pressure chamber (70), a rotary hemostasis valve (RHV) configured fluidly coupling the pressure chamber to the device lumen and for allowing passage of the inner elongate intravascular device therethrough, and a fluid pressure oscillator (66) configured for oscillating a fluid pressure in the pressure chamber, such that a fluid pressure within the device lumen is oscillated, thereby mechanically vibrating the outer elongate intravascular device.

Description

FLUID PRESSURE OSCILLATOR DRIVEN DYNAMIC PRESSURE NAVIGATIONAL ASSISTANCE DEVICE

FIELD OF THE INVENTION

[01] The present disclosure relates generally to medical devices and intravascular medical procedures, and more particularly, to devices and methods for navigating elongate devices through a delivery or guide catheter.

BACKGROUND OF THE INVENTION

[02] Intravascular devices (e.g., therapeutic and diagnostic catheters) are commonly used to perform medical procedures within very small spaces in a patient's body, e.g., for diagnosing and/or treating many types of vascular disease. For example, it is often desirable to remove tissue from the body in a minimally invasive manner as possible, so as not to damage other tissues. For example, removal of tissue from within a vasculature, such as blood clots, may improve patient conditions and quality of life.

[03] Many vascular system problems stem from insufficient blood flow through blood vessels. One cause of insufficient or irregular blood flow is a blockage within a blood vessel referred to as a blood clot or thrombus, which may embolize and form an embolus in a patient vasculature. Thrombi can occur for many reasons, including damage to the arterial wall from atherosclerotic disease, trauma caused by surgery, or due to other causes. When a thrombus forms, it may effectively stop the flow of blood through the zone of formation. Sometimes such thrombi are harmlessly dissolved in the blood stream. At other times, however, such thrombi may lodge in a blood vessel where they can partially or completely occlude the flow of blood. If the partially or completely occluded vessel feeds blood to sensitive tissue, such as the brain, lungs or heart, for example, serious tissue damage may result.

[04] For example, thrombosis of one of the carotid arteries can lead to an arterial ischemic stroke (AIS) due to insufficient oxygen supply to vital regions in the brain. As another example, if one of the coronary arteries is 100% thrombosed, the flow of blood is stopped in that artery, resulting in a shortage of oxygen carrying red blood cells, e.g., to supply the muscle (myocardium) of the heart wall. Oxygen deficiency reduces or prohibits muscular activity, can cause chest pain (angina pectoris), and can lead to death of myocardium, which permanently disables the heart to some extent. If the myocardial cell death is extensive, the heart will be unable to pump sufficient blood to supply the body's life sustaining needs. Indeed, a large percentage of the more than 1.2 million heart attacks in the United States are caused by blood clots (thrombi) that form within a coronary artery. As still another example, clots in the peripheral vasculature may result in amputation of a limb.

[05] When symptoms of an occlusion are apparent, immediate action should be taken to reduce or eliminate resultant tissue damage. Indeed, clinical data indicates that clot removal may be beneficial or even necessary to improve outcomes. The ultimate goal of any modality to treat these conditions of the arterial or venous system is to remove the blockage or restore patency, quickly, safely, and cost effectively. One approach is to treat a patient with clot dissolving drugs. These drugs, however, do not immediately dissolve the clot from the patient, and are typically ineffective after a predefined window, usually at 2-3 hours after the symptoms arise from the clot. Other approaches involve thrombectomy, i.e., the removal of the clot by aspiration, mechanical retrieval, or a combination thereof. Mechanical retrieval usually involves a deployable mesh-like grid, such as a stent retriever, and is often complicated and dangerous to perform.

[06] Aspiration thrombectomy is generally an effective and common treatment for removing a clot from a blood vessel, especially in the case of AIS. In a typical endovascular aspiration thrombectomy procedure, a catheter is introduced into the vasculature of the patient until the distal end of a catheter is just proximal to the clot, and a vacuum is applied at the proximal end of the catheter, resulting in the ingestion and subsequent removal of at least a portion of the clot into the catheter. Most aspiration systems are susceptible to tip clogging when the clot that is being aspirated is too large for the aspiration conduit at the distal end of the catheter. Current technology for endovascular thrombectomy in ischemic stroke utilizes static loading. Once tip clogging occurs, the pressure in the system precipitously drops to a level that often results in boiling or cavitation of the aspirate within the system. As a result, water vapor is introduced into the system, thereby decreasing the efficiency of the aspiration, and in turn, making it more difficult, if not impossible, to ingest the clot into the catheter. [07] Current trends towards enhancement of aspiration efficacy have seen a few technological advancements. In one approach, catheters with larger inner diameters may be used to facilitate clot evacuation by allowing potentially greater clot pulling forces due to increased suction area and/or by reduced resistance to thrombus passage into the larger lumen of the catheter. However, the use of such large diameter catheters is limited in that they cannot reach clots located in the relatively small diameter vessels of the vasculature of the patient.

[08] Another approach uses “cyclic aspiration” to dynamically load the suction pressure during aspiration in various manners to disrupt the structure of the clot and lessen the resistance to ingestion of a given aspiration catheter, thus improving efficiency, and allowing use of potentially smaller, more trackable, catheters to achieve the same or better outcomes than less trackable larger catheters.

[09] One system for dynamically loading the suction pressure employs a cyclically activated valve or similar configuration to achieve the pressure pulsing by blocking main stream flow. Typically, this is done by hand, or via an electro-mechanical or pneumatic valve that blocks aspirate flow from an attached aspiration catheter to the pump for a specified time interval. In some instances, pressure sensing feedback has been suggested as a means for determining when to activate the valve. One cyclical loading method, described in Simon S, Grey CP, Massenzo T, et al., “Exploring the efficacy of cyclic vs static aspiration in a cerebral thrombectomy model: an initial proof of concept study,” Journal of Neurolnterventional Surgery 2014;6:677- 683 and PCT Publication WO2014151209A8, employs a venting mechanism that is automatically placed in an oscillatory pulse mode in response to the application of vacuum to the attached aspiration catheter.

[10] Another cyclic aspiration system for dynamically loading the suction pressure, described in U.S. Patent Nos. 11 ,547,426 and 11 ,337,712, comprises a vacuum source and a pressurized fluid source of fluid individually connected via valves to a manifold that is fluidly coupled to an attached aspiration catheter. Such valvebased cyclic aspiration systems are somewhat limited in their ability to precisely generate desired pressure waveforms, as the time resolved pressure within the manifold is dependent on numerous fixed parameters, such as, e.g., the volume, shape, resistance, and compliance of the spaces and connections within the manifold; the configuration, orifice size, resistances and opening time of the valves; on the lag of the electronics system used to sense pressure and control the valves; the length and resistances of the connections and valving to the vacuum and vent base pressures of the vacuum and vent fluid; and the inner diameter (ID), length, and compliance of the aspiration catheter, high quantity of saline used to maximize aspiration effectiveness, etc. [11] While the pressure extremes of a pressure waveform generated by these valve-based systems may be regulated by various means, such as adjusting valve settings to, and base pressures of the vacuum and vent sources, it is much more difficult to alter the shape of the pressure waveform. In particular, flow resistances within the system can limit the rate of pressure change. Furthermore, compliances within the fluidic tubing connections and the aspiration catheter can introduce secondary pressure oscillations. These behaviors can be optimized for a given set of operational parameters by altering the system hardware design and material choices, but changing them on-the-fly while the system is in use would be difficult to achieve. For example, in electronically controlled flow systems, solenoid-based valves are extensively used; however, they cannot be controlled beyond the basic opening and closing functions to alter the shape of the pressure and vacuum profiles. Even if feedback is employed, it is difficult to predict the pressure at the distal end of the aspiration catheter without fully understanding all of the aforementioned parameters, as well as changing environmental conditions, including a change in altitude.

[12] Notably, the shape of the pressure waveform generated at the distal end of the aspiration catheter, and in particular, the rate of change of the pressures and their frequencies are related to the degree of pressure effects imparted on the target thrombus, and thus can have a considerable influence on the efficacy of a dynamic pressure aspiration system. Therefore, having greater control over the shape of the pressure waveform at the distal end of the aspiration catheter would potentially have significant impact on the ability to optimize an enhanced aspiration system. However, because valve-based systems are somewhat limited in their ability to precisely generate pressure waveforms, their ability to effectively aspirate thrombi is degraded.

[13] Furthermore, to generate pressure waveforms that vary between the vent pressure and the baseline vacuum pressure, these valve-based systems require a vacuum source that supplies a relatively high baseline vacuum (very low absolute baseline pressure). Such vacuum sources must exhibit high performance, and are thus, more costly. Furthermore, due to the relatively high baseline vacuum required by these valve-based systems, a substantial amount of blood may be lost and/or vessel collapse may occur when a clot is not being actively ingested by the aspiration catheter. Furthermore, these valve-based systems require a constant source of saline to increase the level of the pressure waveform (i.e., pressurize the system) when vent valve is open. All of the saline that flows from the source ends up, along with any tissue (e.g. , blood or thrombus) aspirated from the patient, in an aspirate collection container, which must be replaced once full. Furthermore, although it is desirable to determine the nature and amount of tissue collected from the patient (e.g., to confirm that the thrombus has been removed from the patient and to ensure that an excessive amount of blood is not being removed from the patient), such determination may be difficult to make given the amount of saline within the aspirate collection container. For example, oftentimes the only indication that tissue has been removed from the patient is that the fluid within aspirate collection container has a pinkish hue, which may provide no indication as to the nature and amount of tissue removed from the patient.

[14] There, thus, is an ongoing need for dynamic cyclical aspiration system that can more accurately and precisely generate a pressure waveform at the distal end of the aspiration catheter using a relatively low source of vacuum and a relatively small amount of saline.

[15] Most intravascular medical procedures, such as aspiration thrombectomy, mandate precise catheter navigation prior to performing such medical procedures. In general, a suitable intravascular device is inserted into the vascular system of the patient and navigated through the vasculature to a target tissue site TS. For example, to access a target site TS within the human body from a remote location, an intravascular device is typically passed through one or more body lumens, such as through the vascular system, to the target site TS. When the vascular system is used, the intravascular device is inserted into an artery or vein percutaneously or through a relatively small incision in the patient's body. The intravascular device is then threaded through the patient's system of blood vessels to reach the target tissue site TS. Often, a pathway is created through the vasculature to the target site TS with the use of a delivery device, such as a guide catheter, through which a therapeutic or diagnostic catheter can be guided to the target site TS. Using this method, virtually any target site TS in the patient’s vascular system may be accessed, including the coronary, cerebral, and peripheral vasculature.

[16] During one conventional endovascular procedure, a guide sheath is inserted into a patient’s femoral artery through an introducer and into the vasculature of the patient. A guidewire is then inserted into the guide sheath and maneuvered through the patient’s arterial system until the guidewire reaches a target intravascular site. A working catheter is then moved along the guidewire until the distal end of the working catheter is positioned proximate the target intravascular site. The working catheter can then be operated to perform the diagnostic and/or therapeutic procedure at the target intravascular site. Manipulation of the catheters and guidewires typically requires these devices to be manually advanced and rotated to facilitate their navigation through the tortuous vasculature of the patient. Rotary hemostasis valves (RHVs) are typically used between fluid manifolds and the respective catheters to provide fluid to the catheters and prevent backflow of blood through the catheters, while allowing rotation of the catheters during catheter manipulations.

[17] Navigating relatively large bore intravascular devices, such as guide sheaths and catheters, through the often-tortuous vasculature of a patient requires reliable and precise navigation, which is an extremely tedious process, requiring a substantial amount of time and skill, and potentially causes a high degree of fatigue in the surgeon. For example, it is difficult for such relatively large bore intravascular devices to be navigated proximate to the target intravascular site located within the highly tortuous intracranial vasculature due to the buildup of static frictional contact points in bends in the intracranial vasculature. As such, a guide sheath will be typically navigated within the patient significantly proximal to a target intravascular site located within the intracranial vasculature of the patient. The catheter will then be advanced through the guide sheath and then navigated past the distal end of the guide sheath to the target intravascular site. Such navigation of the catheter will be complicated in proportion to the amount and degree of vascular tortuosity involved. In an effort to distally advance the catheter beyond the guide sheath, the physician may need to perform additional manual manipulations on the catheter to overcome the static friction, or even may have to retract the catheter.

[18] There, thus, is an ongoing need to facilitate the navigation of an intravascular device within a highly tortuous vasculature of a patient to a target intravascular site.

SUMMARY OF THE INVENTION

[19] In accordance with a first aspect of the present inventions, a navigation assistance device for use with an outer elongate intravascular device having a device lumen and an inner elongate intravascular device disposed within the device lumen is provided.

[20] The navigation assistance device comprises a pressure chamber ,and a rotary hemostasis valve (RHV) configured fluidly coupling the pressure chamber to the device lumen and for allowing passage of the inner elongate intravascular device therethrough. The navigation assistance device further comprises a fluid pressure oscillator configured for oscillating a fluid pressure in the pressure chamber (e.g., at a frequency in the range of 0.1 Hz-100Hz, and more specifically, at a frequency in the range of 0.5Hz-50Hz), such that a fluid pressure within the device lumen is oscillated, thereby mechanically vibrating the outer elongate intravascular device.

[21] In one embodiment, the RHV may comprise a guide tube having a tube lumen configured for allowing passage of the inner elongate intravascular device therethrough, and a connector rotatably affixed to a distal end of the guide tube. The tube lumen may be sealed to prevent backflow of blood therethrough, while the connector may be configured for being coupled to a proximal end of outer elongate intravascular device, such that the tube lumen is in fluid communication with the device lumen.

[22] In one version of this embodiment, the navigation assistance device may further comprise a pressure manifold comprising the pressure chamber, the guide tube, and a distal pressure port configured for fluidly coupling the tube lumen to the device lumen when the connector is coupled to the proximal end of the outer elongate intravascular device. The guide tube may be disposed within the pressure chamber and has at least one tube opening (e.g., a plurality of tube openings formed through the wall of the guide tube) fluidly coupling the pressure chamber to the tube lumen, while the fluid pressure oscillator may be configured for oscillating a fluid pressure in the pressure chamber, such that a fluid pressure within the tube lumen is oscillated via the tube opening(s).

[23] In another version of this embodiment, the RHV may be external to the pressure chamber, in which case, the RHV may further comprise a side arm affixed to the guide tube. The side arm may have a side arm lumen in fluid communication with the tube lumen, in which case, the pressure chamber may be configured for being in fluid communication with the tube lumen via the side arm lumen.

[24] In another embodiment, the pressure chamber may be configured for having a variable volume of pressure oscillating fluid, in which case, the fluid pressure oscillator may be configured for oscillating the variable volume of fluid within the pressure chamber. In this embodiment, the navigation assistance device may further comprise a vent inlet configured for fluidly coupling a pressurized fluid source having a baseline elevated pressure to the pressure chamber, in which case, the fluid pressure oscillator may be configured for oscillating the fluid pressure in the pressure chamber by oscillating the fluid pressure around the baseline elevated pressure. In this embodiment, the navigation assistance device may further a fluid refill control element configured for selectively fluidly coupling the pressurized fluid source to the pressure chamber. For example, when a fluid pressure within the pressure chamber drops below a threshold fluid pressure, the fluid refill control element may be configured for conveying fluid from the pressurized fluid source into the pressure chamber.

[25] An intravascular medical system may comprise the navigation assistance device, the outer elongate intravascular device, and the inner elongate intravascular device. In one embodiment, the outer elongate intravascular device is a guide sheath, and the inner elongate intravascular device is a working catheter. In another embodiment, the outer elongate intravascular device is a working catheter, and the inner elongate intravascular device is a guide wire. In still another embodiment, at least one of the outer elongate intravascular device and another elongate intravascular device (e.g., the inner elongate intravascular device or a dedicated obturator) configured for insertion into the inner lumen of the outer elongate intravascular device comprises a discontinuity that decreases a clearance between the other elongate intravascular device and the device lumen, such that a magnitude of the mechanical vibration is increased at the discontinuity.

[26] A method of using the navigation assistance device may comprise introducing the outer elongate intravascular device within a vasculature of a patient, coupling the navigation assistance device to a proximal end of the outer elongate intravascular device, passing the inner elongate intravascular device through the tube lumen, introducing the inner elongate intravascular device into the device lumen, navigating the outer elongate intravascular device within the vasculature of the patient to a target tissue site, and operating the fluid pressure oscillator, thereby mechanically vibrating the outer elongate intravascular device as the outer elongate intravascular device is navigated within the vasculature of the patient to the target tissue site.

[27] In one method, the fluid pressure oscillator may be continually operated as the outer elongate intravascular device is navigated within the vasculature of the patient to the target tissue site, such that a buildup of static friction at a lengthwise portion of the outer elongate intravascular device through a bend in the vasculature is prevented that would otherwise hinder distal advancement of the lengthwise portion of the outer elongate intravascular device through the bend in the vasculature. In another method, navigation of the outer elongate intravascular device within a bend in the vasculature of the patient causes a buildup of static friction at a lengthwise portion of the outer elongate intravascular device, thereby hindering distal advancement of the lengthwise portion of the outer elongate intravascular device through the bend, in which case, the fluid pressure oscillator may be operated as the lengthwise portion of the outer elongate intravascular device is disposed within the bend, thereby releasing the buildup of static friction and facilitating distal advancement of the lengthwise portion of the outer elongate intravascular device through the bend in the vasculature of the patient.

[28] In still another method, the outer elongate intravascular device may be a guide sheath, and the inner elongate intravascular device may be one of a working catheter and a guide wire. In yet another method, the inner elongate intravascular device may be a guide wire, in which case, the method may further comprise navigating the guide wire within the vasculature of the patient to the target tissue site, and the outer elongate intravascular device may be navigated within the vasculature of the patient over the guide wire to the target tissue site while the guide wire is at the target tissue site. In yet another method, one of the outer elongate intravascular device and the inner elongate intravascular device may be a working catheter having an operative element, in which case, the method may further comprise operating the operative element to perform a medical procedure at the target tissue site. If the patient has a thrombus at the target tissue site, the working catheter may be an aspiration catheter, the operative element may be a distal aspiration port, and the medical procedure may comprise aspirating the thrombus within the distal aspiration port.

[29] In accordance with a second aspect of the present inventions, a navigation assistance/aspiration device for use with an aspiration catheter having an aspiration lumen and a distal aspiration port is provided.

[30] The navigation assistance/aspiration device comprises a pressure manifold comprising a pressure chamber, a distal pressure port configured for fluidly coupling the aspiration catheter to the pressure chamber, a vent inlet configured for fluidly coupling a pressurized fluid source to the pressure chamber, thereby allowing the pressurized fluid source to apply a baseline elevated pressure to the pressure chamber, and a vacuum outlet configured for fluidly coupling a vacuum source to the pressure chamber, thereby allowing the vacuum source to apply a baseline vacuum pressure to the pressure chamber.

[31] The navigation assistance/aspiration device further comprises a controller configured for selectively fluidly coupling the pressurized fluid source to the pressure chamber via the vent inlet or fluidly coupling the vacuum source to the pressure chamber via the vacuum outlet.

[32] The navigation assistance/aspiration device further comprises a fluid pressure oscillator configured for oscillating the variable volume of pressure modulating fluid within the pressure chamber, such that the baseline elevated pressure within the pressure chamber is modulated when the controller fluidly couples the pressurized fluid source to the pressure chamber via the vent inlet, and the baseline vacuum pressure within the pressure chamber is modulated when the controller fluidly couples the vacuum source to the pressure chamber. In one embodiment, the pressure chamber may be configured for having a variable volume of pressure oscillating fluid, in which case, the fluid pressure oscillator may be configured for oscillating the variable volume of fluid within the pressure chamber. In another embodiment, the fluid pressure oscillator may be configured for oscillating the fluid pressure in the pressure chamber at a frequency in the range of 0.1 Hz-100Hz when the pressurized fluid source is fluidly coupled to the pressure chamber, and for oscillating the fluid pressure in the pressure chamber at a frequency in the range of 1 Hz-20Hz when the vacuum source is fluidly coupled to the pressure chamber.

[33] In still another embodiment, the baseline elevated pressure may be above the mean arterial pressure (MAP) of a patient. In this embodiment, the vent inlet may be further configured for fluidly coupling an atmospheric fluid source to the pressure chamber, and the controller may be further configured for selectively fluidly coupling the atmospheric fluid source to the pressure chamber via the vent inlet concurrently with fluidly coupling the vacuum source to the pressure chamber via the vacuum outlet. In this embodiment, the navigation assistance/aspiration device may further comprise a fluid refill control element configured for conveying fluid from the pressurized fluid source into the pressure chamber when a fluid pressure within the pressure chamber drops below a threshold fluid pressure or means for selectively fluidly coupling the pressurized fluid source or the atmospheric pressure source to the vent inlet.

[34] In yet anotherembodiment, the navigation assistance/aspiration device may further comprise a rotary hemostasis valve (RHV) fluidly coupling the pressure chamber to the aspiration lumen of the aspiration catheter. In this embodiment, the RHV may comprise a guide tube having a tube lumen configured for allowing passage of a guide wire therethrough, and a connector rotatably affixed to a distal end of the guide tube. The tube lumen may be sealed to prevent backflow of blood therethrough, and the configured may be coupled to a proximal end of the aspiration catheter, such that the tube lumen is in fluid communication with the aspiration lumen.

[35] In one version of this embodiment, the pressure manifold may further comprise the guide tube, in which case, the guide tube may be disposed within the pressure chamber and may have at least one tube opening (e.g., a plurality of tube openings formed through a wall of the guide tube) fluidly coupling the pressure chamber to the tube lumen, the distal pressure port may be configured for fluidly coupling the tube lumen to the device lumen when the connector is coupled to the proximal end of the aspiration catheter, and the fluid pressure oscillator may be configured for oscillating a fluid pressure in the pressure chamber, such that a fluid pressure within the tube lumen is oscillated via the tube opening(s).

[36] In another version of this embodiment, the RHV may be external to the pressure chamber, in which case, the RHV may further comprise a side arm affixed to the guide tube. The side arm may have a side arm lumen in fluid communication with the tube lumen, in which case, the pressure chamber may be configured for being in fluid communication with the tube lumen via the side arm lumen.

[37] In yet another embodiment the controller may be further configured for outputting a waveform signal corresponding to a modulated therapeutic pressure waveform, in which case, the fluid pressure oscillator is configured for oscillating the variable volume of the pressure modulating fluid within the pressure chamber in accordance with the waveform signal, thereby modulating the baseline vacuum pressure. In this embodiment, the navigation assistance/aspiration device may further comprise a sensor configured for measuring a parameter indicative of a fluid pressure at the distal end of the aspiration catheter, in which case, the controller may be configured for, in response to the measured parameter, dynamically modifying the waveform signal, and the fluid pressure oscillator may be configured for oscillating the variable volume of the pressure modulating fluid within the pressure chamber in accordance with the dynamically modified waveform signal, such that the fluid pressure at the distal end of the aspiration catheter tracks a desired modulated pressure waveform. [38] An intravascular medical system may comprise the navigation assistance/aspiration device, the aspiration catheter, and a guide wire for insertion into the aspiration lumen. In one embodiment, one of the aspiration catheter and an elongate intravascular device (e.g., the guide wire or a dedicated obturator) configured for insertion into the aspiration lumen comprises a discontinuity that decreases a clearance between the elongate intravascular device and the aspiration lumen, such that a magnitude of the mechanical vibration is increased at the discontinuity.

[39] A method of using the navigation assistance/aspiration device may comprise introducing the aspiration catheter within a vasculature of a patient, coupling the navigation assistance/aspiration device to a proximal end of aspiration catheter, navigating the aspiration catheter within the vasculature of the patient to a target tissue site, operating the fluid pressure oscillator (e.g., at a frequency in the range of 0.1 Hz- 100Hz), thereby mechanically vibrating the aspiration catheter as the aspiration catheter is navigated within the vasculature of the patient to the target tissue site, and operating the fluid pressure oscillator when the aspiration catheter is at the target tissue site (e.g., at a frequency in the range 1 Hz-20Hz), thereby aspirating the thrombus into the distal aspiration port and through the aspiration lumen.

[40] One method further comprises fluidly coupling the pressurized fluid source to the pressure chamber when the aspiration catheter is navigated within the vasculature of the patient to the target tissue site, and fluidly coupling the vacuum source to the pressure chamber when the aspiration catheter is aspirating the thrombus through the aspiration lumen.

[41] In another method, the fluid pressure oscillator is continually operated as the aspiration catheter is navigated within the vasculature of the patient to the target tissue site, such that a buildup of static friction at a lengthwise portion of the aspiration catheter through a bend in the vasculature is prevented that would otherwise hinder distal advancement of the lengthwise portion of the aspiration catheter through the bend in the vasculature. In still another, navigation of the aspiration catheter within a bend in the vasculature of the patient causes a buildup of static friction at a lengthwise portion of the aspiration catheter, thereby hindering distal advancement of the lengthwise portion of the aspiration catheter through the bend, in which case, the fluid pressure oscillator may be operated as the lengthwise portion of the aspiration catheter is disposed within the bend, thereby releasing the buildup of static friction and facilitating distal advancement of the lengthwise portion of the aspiration catheter through the bend in the vasculature of the patient.

[42] Still another method may further comprise navigating a guide wire within the vasculature of the patient to the target tissue site, in which case, the aspiration catheter may be navigated within the vasculature of the patient over the guide wire to the target tissue site while the guide wire is at the target tissue site. The guide wire may be removed from the aspiration lumen of the aspiration catheter prior to aspirating the thrombus with the aspiration catheter.

[43] Yet another method further comprises introducing a guide sheath having an inner sheath lumen within a vasculature of a patient, and introducing the guide wire through the inner sheath lumen, in which case, introducing the aspiration catheter within the vasculature of the patient may comprise distally advancing aspiration catheter over the guide wire and through the inner sheath lumen until the distal aspiration port of aspiration catheter exits the inner sheath lumen, and navigating the aspiration catheter within the vasculature of the patient to the target tissue site may comprise navigating the aspiration catheter over the guide wire until the distal aspiration port of the aspiration catheter is adjacent target tissue site.

[44] In accordance with a third aspect of the present invention, a method of performing a medical procedure at a target tissue site within the vasculature of a patient is provided.

[45] The method comprises navigating an elongate intravascular device having a device lumen within the vasculature of the patient to the target tissue site, initially oscillating a fluid pressure within the device lumen (e.g., modulating a baseline elevated pressure greater than the mean arterial pressure (MAP) of the patient at a frequency in the range of 0.1 Hz-100Hz) while the elongate intravascular device is navigated within the vasculature of the patient to the target tissue site, thereby mechanically vibrating the elongate intravascular device, and performing a medical procedure at the target tissue site.

[46] In one method, initially oscillating a fluid pressure within the device lumen comprises modulating a baseline elevated pressure greater than a mean arterial pressure (MAP) of the patient. In another method, the fluid pressure in the device lumen is continually oscillated as the elongate intravascular device may be navigated within the vasculature of the patient to the target tissue site, such that a buildup of static friction at a lengthwise portion of the elongate intravascular device through a bend in the vasculature is prevented that would otherwise hinder distal advancement of the lengthwise portion of the elongate intravascular device through the bend in the vasculature. In still another method, navigation of the elongate intravascular device within a bend in the vasculature of the patient causes a buildup of static friction at a lengthwise portion of the elongate intravascular device, thereby hindering distal advancement of the lengthwise portion of the elongate intravascular device through the bend, in which case, the fluid pressure in the device lumen may be oscillated as the lengthwise portion of the elongate intravascular device is disposed within the bend, thereby releasing the buildup of static friction and facilitating distal advancement of the lengthwise portion of the elongate intravascular device through the bend in the vasculature of the patient.

[47] Yet another method further comprises introducing a guide wire into the device lumen, and navigating the guide wire within the vasculature of the patient to the target tissue site, in which case, the elongate intravascular device may be navigated within the vasculature of the patient over the guide wire to the target tissue site while the guide wire is at the target tissue site. In yet another method, the elongate intravascular device is a guide sheath, and the device lumen is an inner sheath lumen, in which case, the method may further comprise distally advancing a working catheter having an operative element through the inner sheath lumen when the guide sheath is at the target tissue site until the operative element exits the inner sheath lumen. The medical procedure at the target tissue site may be performed by the operative element of the working catheter. In yet another method, elongate intravascular device is a working catheter having an operative element, and the medical procedure is performed at the target tissue site with the operative element. For example, the patient may have a thrombus at the target tissue site, the working catheter may be an aspiration catheter, the device lumen may be an aspiration lumen, the operative element may be a distal aspiration port, and the medical procedure may comprise aspirating the thrombus within the distal aspiration port and through the aspiration lumen. Aspirating the thrombus within the distal aspiration port may comprise subsequently oscillating a fluid pressure within the aspiration lumen (e.g., modulating a baseline vacuum pressure less than the MAP of the patient at a frequency in the range of frequency in the range of 1 Hz-20Hz). [48] Other and further aspects and features of embodiments of the disclosed inventions will become apparent from the ensuing detailed description in view of the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[49] The drawings illustrate the design and utility of preferred embodiments of the disclosed inventions, in which similar elements are referred to by common reference numerals. It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are represented by like reference numerals throughout the figures. It should also be noted that the figures are only intended to facilitate the description of the embodiments. They are not intended as an exhaustive description of the invention or as a limitation on the scope of the invention, which is defined only by the appended claims and their equivalents. In addition, an illustrated embodiment of the disclosed inventions needs not have all the aspects or advantages shown. Further, an aspect or an advantage described in conjunction with a particular embodiment of the disclosed inventions is not necessarily limited to that embodiment and can be practiced in any other embodiments even if not so illustrated.

[50] In order to better appreciate how the above-recited and other advantages and objects of the disclosed inventions are obtained, a more particular description of the disclosed inventions briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated in the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

[51] Fig. 1 is a block diagram of one embodiment of a medical system constructed in accordance with the present inventions;

[52] Fig. 2 is a profile view of one embodiment of a coaxial catheter assembly used in the medical system of Fig. 1 ;

[53] Fig. 3 is a cross-sectional view of the coaxial catheter assembly of Fig. 2, taken along the line 3-3;

[54] Fig. 4 is a top view of a patient with the coaxial catheter assembly of Fig. 2 delivered into the vasculature of the patient; [55] Fig. 5 is a longitudinal sectional view of one embodiment of the guide sheath and working catheter of the coaxial catheter assembly of Fig. 2;

[56] Fig. 6A is a cross-sectional view of the guide sheath and working catheter of Fig. 5, taken along the line 6A-6A;

[57] Fig. 6B is a cross-sectional view of the guide sheath and working catheter of Fig. 5, taken along the line 6B-6B;

[58] Fig. 7 is a longitudinal sectional view of another embodiment of the guide sheath and working catheter of the coaxial catheter assembly of Fig. 2;

[59] Fig. 8A is a cross-sectional view of the guide sheath and working catheter of Fig. 7, taken along the line 8A-8A;

[60] Fig. 8B is a cross-sectional view of the guide sheath and working catheter of Fig. 7, taken along the line 8B-8B;

[61] Fig. 9 is a longitudinal sectional view of an embodiment of a guide sheath of the coaxial catheter assembly and a dedicated obturator;

[62] Fig. 10 is a longitudinal sectional view of the dedicated obturator of Fig. 9;

[63] Fig. 11 A is a cross-sectional view of the dedicated obturator of Fig. 9, taken along the line 11A-11A;

[64] Fig. 11 B is a cross-sectional view of the dedicated obturator of Fig. 9, taken along the line 11B-11 B;

[65] Fig. 11 C is a cross-sectional view of the dedicated obturator of Fig. 9, taken along the line 11C-11C;

[66] Figs. 12A-12C are plan views of one embodiment of a catheter navigation device that can be employed in the medical system of Fig. 1 , particularly showing a fluid pressure oscillator of the catheter navigation device in three different states;

[67] Figs. 13A-13C are plan views of another embodiment of a catheter navigation device that can be employed in the medical system of Fig. 1 , particularly showing a fluid pressure oscillator of the catheter navigation device in three different states;

[68] Fig. 14 is a block diagram of another embodiment of a medical system constructed in accordance with the present inventions;

[69] Fig. 15 is a timing diagram illustrating an exemplary therapeutic pressure waveform generated by the medical system of Fig. 14;

[70] Figs. 16A-16C are plan views of one embodiment of a catheter navigation/aspiration device that can be employed in the medical system of Fig. 14, particularly showing a fluid pressure oscillator of the catheter navigation device in three different states;

[71] Figs. 17A-17C are plan views of another embodiment of a catheter navigation/aspiration device that can be employed in the medical system of Fig. 14, particularly showing a fluid pressure oscillator of the catheter navigation device in three different states;

[72] Fig. 18 is a plan view of still another embodiment of a catheter navigation/aspiration device that can be employed in the medical system of Fig. 14;

[73] Fig. 19 is a flow diagram illustrating one method of navigating a working catheter and performing a medical procedure within the vasculature of a patient; and

[74] Figs. 20A-20G are plan views showing the navigation of a working catheter and performance of a medical procedure within the vasculature of the patient in accordance with the method of Fig. 19;

[75] Fig. 21 is a flow diagram illustrating another method of navigating a working catheter and performing a medical procedure within the vasculature of a patient; and

[76] Figs. 22A-22G are plan views showing the navigation of a working catheter and performance of a medical procedure within the vasculature of the patient in accordance with the method of Fig. 21 .

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[77] Referring to Fig. 1 , one embodiment of a medical system 10 constructed accordance with the disclosed inventions will now be described. The medical system 10 generally comprises a coaxial catheter assembly 12, a pressurized fluid source 14, and a navigation assistance device 16. As will be described in further detail below, the navigation assistance device 16 is configured for oscillating fluid pressure supplied by the pressure fluid source 14 within a lumened component of the coaxial catheter assembly 12 (in this case, a guide sheath (described in further detail below) of the coaxial catheter assembly 12), thereby mechanically vibrating, and thus facilitating the navigation of, the guide sheath through the vasculature V of the patient P (illustrated in Fig. 4).

[78] As best illustrated in Fig. 2, the coaxial catheter assembly 12 comprises a first elongate intravascular device 22 (in this case, a guide sheath) having a device lumen, a second elongate intravascular device 24 (in this case, a working catheter (e.g., a microcatheter) having a device lumen, and a third elongate intravascular device 26 (in this case, a guidewire 26) coaxially arranged with respect to each other. That is, the guidewire 26 is sized to be slidably received within the working catheter 24, and the working catheter 24 is sized to be slidably received within the guide sheath 22. Thus, the guide sheath 22 may be considered an outer elongate intravascular device relative to the working catheter 24 and guide wire 26, the working catheter 24 may be considered an outer elongate intravascular device relative to the guide wire 26, the guide wire 26 may be considered an inner elongate intravascular device as to the guide sheath 22 and the working catheter 24, and the working catheter 24 may be considered an inner elongate intravascular device relative to the guide sheath 22.

[79] The coaxial catheter assembly 12 may be, e.g., inserted through the vasculature V of a patient P, as illustrated in Fig. 4, such as natural body lumens (e.g., blood vessels (artery, chamber of the heart, or vein), urinary system vessels (renal collection ducts, calix, ureter, bladder, or urethra), hepatobiliary vessels (hapatic and pancreatic ducts, chyle ducts, common or cystic duct), gastrointestinal tract (esophagus, stomach, small and large intestine, cecum, rectum) gynecological tract (cervix, uterus), fallopian tube or milk ducts and mammary canals of breast), nasophyarynx (eustacean tube, sinuses, tear duct), seminal vesicle, spinal canal, or ventricles of the brain). The coaxial catheter assembly 12 may be introduced into the patient P by percutaneous access, surgical access, or through natural orifices (oral, rectal, nasal, otic, optic, or urethral).

[80] The guide sheath 22 is configured for facilitating access for the working catheter 24 to target tissue site in the vasculature V of the patient P. The guide sheath 22 generally includes an elongate sheath body 28 having a proximal end 30 and a distal end 32, an inner lumen 34 (best shown in Fig. 3) that extends entirely through the sheath body 28 between the proximal end 30 and distal end 32, and a proximal adapter 36 affixed to the proximal end 30 of the sheath body 28.

[81] The sheath body 28 is substantially pliable or flexible (although generally more rigid than the smaller diameter working catheter 24), such that when it is advanced into the patient, an operator (e.g., the surgeon) may easily manipulate the sheath body 28 to conform, adopt, or match the shape or curvatures of the internal pathways (e.g., gastrointestinal tract, blood vessels, etc.) of the patient. The sheath body 28 may be introduced into the patient via an arterial access sheath (not shown), although an arterial access sheath may not be required if the sheath body 28 is introduced into the patient via a natural orifice. In the illustrated embodiment, the sheath body 28 has a circular cross-section, although other cross-sectional geometries, such as rectangular, can be used. The sheath body 28 may be comprised of multiple layers of materials and/or multiple tube structures that exhibit a low bending stiffness, while providing a high axial stiffness along the neutral axis. Typical designs include a nitinol spine encapsulated in braid and any flexible, pliable, or suitable polymer material or bio-compatible polymer material or a braided plastic composite structure composed of low durometer plastics (e.g., nylon-12, Pebax®, polyurethanes, polyethylenes, etc.).

[82] The guide sheath 22 may include a plurality of regions along its length having different configurations and/or characteristics. For example, a distal portion of the sheath body 28 may have an outer diameter less than the outer diameter of a proximal portion of the sheath body 28 to reduce the profile of the distal portion of the sheath body 28 and facilitate navigation through the vasculature V of the patient P. Furthermore, the distal portion of the sheath body 28 may be more flexible than the proximal portion of the sheath body 28. Generally, the proximal portion of the sheath body 28 may be formed from material that is stiffer than the distal portion of the sheath body 28, so that the proximal portion has sufficient pushability to advance through the vasculature V of the patient P, while the distal portion may be formed of a more flexible material so that it may remain flexible and track more easily over a guidewire to access remote locations in tortuous regions of the vasculature V.

[83] The geometry and size of the inner lumen 34 will be selected in accordance with the cross-sectional geometry and size of the working catheter 24. The sheath body 28 may have a low-friction inner layer (e.g., a coating of silicone or polytetrafluoroethylene) to provide a low-friction surface to accommodate movement of the working catheter 24 within the inner lumen 34 of the guide sheath 22. The proximal adapter 36 may be configured for both mechanically and fluidly coupling the guide sheath 22 to a rotary hemostasis valve RHV (not shown). As shown in Fig 4, the proximal end 30 of the guide sheath 22 remains outside of a vasculature V of the patient P and accessible to the surgeon, while the distal end 32 of the guide sheath 22 is sized and dimensioned to reach a remote location of the vasculature V of the patient P.

[84] In an optional embodiment, the guide sheath 22 may have active steering capability, such that the distal end 32 of the sheath body 28 may be articulated into simple or complex shapes or curvatures that may conform to various shapes or curvatures of internal pathways of the patient to reach a target tissue site in the vasculature V of the patient P. For example, the guide sheath 22 may have one or more steering elements (such as pull wires (not shown)), extending through the sheath body 28, which can be operated to effect the desired shape or curvature at the distal end 32 of the sheath body 28.

[85] The working catheter 24 is configured for performing an interventional and/or diagnostic procedure at the target tissue site. For example, the working catheter 24 may be a stent delivery catheter, a balloon catheter, an electrophysiology catheter, ultrasound imaging catheter, atherectomy catheter, vaso-occlusive device delivery catheter, contrast/medicine delivery catheter, etc. In the embodiment described below, the working catheter 24 is an aspiration catheter for removing thrombi from the vasculature V of the patient P.

[86] The working catheter 24 generally includes an elongate catheter body 38 having a proximal end 40 and a distal end 42, an inner lumen 44 (shown best in Fig. 3) that extends entirely through the catheter body 38 between the proximal end 40 and distal end 42, a proximal adapter 46 affixed to the proximal end 40 of the catheter body 38, and an operative element 48 (e.g., a stent, balloon, mapping electrodes, ultrasound element, tissue cutting blade, vaso-occlusive devices, fluid port, etc.) carried by the distal end 42 of the catheter body 38.

[87] The working catheter 24 passes through the inner lumen 34 of the guide sheath 22, and is thus, moveable relative thereto. The working catheter 24 may be movably positioned within the inner lumen 34 of the guide sheath 22 to enable relative insertion of the guide sheath 22 and working catheter 24, relative rotation or “roll” of the guide sheath 22 and working catheter 24, and optionally, relative steering or bending of the guide sheath 22 and working catheter 24 relative to each other, particularly when the distal end 42 of the catheter body 38 is inserted beyond the distal end 32 of the sheath body 28. As shown in Fig. 2, the working catheter 24 projects distally with respect to the distal end 32 of the sheath body 28. Of course, the working catheter 24 may be withdrawn proximally such that the distal end 42 of the catheter body 38 is substantially flush with the distal end 32 of the sheath body 28, or withdrawn proximally even further such that the distal end 32 of the catheter body 38 is retracted within the distal end 32 of the sheath body 28.

[88] The catheter body 38 is substantially pliable or flexible, such that it can be advanced through the inner lumen 34 of the guide sheath 22 when the sheath body 28 conforms to the shape or curvatures of the internal pathways of the patient. In the illustrated embodiment, the catheter body 38 has a circular cross-section, although other cross-sectional geometries, such as rectangular, can be used. The working catheter 24 may include a plurality of regions along its length having different configurations and/or characteristics. For example, a distal portion of the catheter body 38 may have an outer diameter less than the outer diameter of a proximal portion of the catheter body 38 to reduce the profile of the distal portion of the catheter body 38 and facilitate navigation through the inner lumen 34 of the guide sheath 22. Furthermore, the distal portion of the catheter body 38 may be more flexible than the proximal portion of the catheter body 38. Generally, the proximal portion of the catheter body 38 may be formed from material that is stiffer than the distal portion of the catheter body 38, so that the proximal portion has sufficient pushability to advance through the vasculature V of the patient P, while the distal portion may be formed of a more flexible material so that it may remain flexible and track more easily over a guidewire to access remote locations in tortuous regions of the vasculature V.

[89] The catheter body 38 may be comprised of multiple layers of materials and/or multiple tube structures that exhibit a low bending stiffness, while providing a high axial stiffness along the neutral axis. The catheter body 38 may be composed of suitable polymeric materials, metals and/or alloys, such as polyethylene, stainless steel or other suitable biocompatible materials or combinations thereof. In some instances, the proximal portion of the catheter body 38 may include a reinforcement layer, such a braided layer or coiled layer to enhance the pushability of the catheter body 38. The catheter body 38 may include a transition region between the proximal portion and the distal portion of the catheter body 38. Typical designs include a nitinol spine encapsulated in braid and any flexible, pliable, or suitable polymer material or bio-compatible polymer material or a braided plastic composite structure composed of low durometer plastics (e.g., nylon-12, Pebax®, polyurethanes, polyethylenes, etc.). Typical designs include a nitinol spine encapsulated in braid and any flexible, pliable, or suitable polymer material or bio-compatible polymer material or a braided plastic composite structure composed of low durometer plastics (e.g., nylon-12, Pebax®, polyurethanes, polyethylenes, etc.). The geometry and size of the inner lumen 44 will be selected in accordance with the cross-sectional geometry and size of the guidewire 26. The catheter body 38 may have a low-friction inner layer (e.g., a coating of silicone or polytetrafluoroethylene) to provide a low-friction surface to accommodate movement of the guidewire 26 within the inner lumen 44 of the working catheter 24. As will be described in further detail below, the proximal adapter 46 is configured for both mechanically and fluidly coupling the working catheter 24 to the navigation assistance device 16.

[90] As shown in Fig. 4, the proximal end 40 of the catheter body 38 remains outside of the vasculature V of the patient P and accessible to the surgeon, while the distal end 42 of the catheter body 38 is sized and dimensioned to reach the target tissue site TS within a remote location of the vasculature V of the patient P. In the illustrated embodiment, the working catheter 24 may be an aspiration catheter, in which case, the inner lumen 44 of the aspiration catheter 24 may be an aspiration lumen, while the operative element 48 may be a distal aspiration port in communication with the aspiration lumen 44. The target tissue site TS may be a thrombus that can be ingested into the distal aspiration port 48 and through the aspiration lumen 44. The thrombus T may be wholly ingested into the aspiration catheter 24 or may be broken up into pieces and ingested piece-by-piece into the aspiration catheter 24. In alternative embodiments, the operative element 48 may be, e.g., a balloon.

[91] In an optional embodiment, the aspiration catheter 24 may have active steering capability, such that the distal end 42 of the catheter body 38 may be articulated into simple or complex shapes or curvatures that may conform to various shapes or curvatures of internal pathways of the patient to reach a target tissue site in the vasculature V of the patient P. For example, the aspiration catheter 24 may have one or more steering elements (such as pull wires (not shown)), extending through the catheter body 38, which can be operated to effect the desired shape or curvature at the distal end 42 of the catheter body 38.

[92] The guidewire 26 may be conventional wire that includes a guidewire body 50 having a proximal end 52 and a distal end 54, and a collet 56 affixed to the proximal end 52 of the guidewire body 50. The collet 56 is configured for being mechanically grasped by the surgeon, such that the guidewire 26 may be linearly and rotationally manipulated. The guidewire body 50 is composed of a suitable material (e.g., metal or metal alloy, such as stainless steel and/or nickel-titanium alloy, or polymer) to provide the guidewire 26 with desirable flexi bil ity/stiffness characteristics. The guidewire body 50 may have a suitable diameter, e.g., 0.125 inches or less, and have a suitable length in the range of 50cm-350cm. As best shown in Fig. 4, the proximal end 52 of the guidewire 26 remains outside of the vasculature V of the patient P and accessible to the surgeon, while the distal end 54 of the guidewire 26 is sized and dimensioned to reach the target tissue site TS within a remote location of the vasculature V of the patient P. As will be described in further detail below, the guidewire 26 may remain in the aspiration lumen 44 during navigation of the aspiration catheter 24 through the inner lumen 34 of the guide sheath 22, and removed from the aspiration lumen 44 during aspiration of one or more thrombi T from the vasculature V of the patient P.

[93] In optional embodiments, one or more features may be added to the guide sheath 22 and/or working catheter 24 to enhance the navigational effect applied by the navigation assistance device 16 at a selected longitudinal region of the guide sheath 22.

[94] For example, as shown in Fig. 5, the aspiration catheter 24 further comprises an optional discontinuity 58 disposed on the catheter body 38, which decreases a clearance between the aspiration catheter 24 and the inner lumen 34 of the guide sheath 22; that is, from the nominal clearance illustrated in Fig. 6B to the decreased clearance illustrated in Fig. 6A. As will be described in further detail below, such discontinuity 58 enhances the navigational effect applied by the navigation assistance device 16 at a selected longitudinal region of the guide sheath 22. For example, the aspiration catheter 24 may be arranged in the inner lumen 34 of the guide sheath 22, such that there is a relatively high clearance between the aspiration catheter 24 and the inner lumen 34 at the proximal end of the guide sheath 22, and a relatively low clearance between the aspiration catheter 24 and the inner lumen 34 at the distal end of the guide sheath 22, thereby defining the region of vibrating or wiggling influence from the proximal adapter 36 to the more distal region of the guide sheath 22.

[95] In the illustrated embodiment, the discontinuity 58 takes the form of a protuberance (or bump) radially extending outward from the catheter body 38, although the discontinuity 58 may take the form of any feature that abruptly decreases the clearance between the aspiration catheter 24 and the inner lumen 34 of the guide sheath 22. Furthermore, although the protuberance 58 radially extends around the catheter body 38 in a continuous manner, the protuberance 58 may alternatively have one or more radial cuts or grooves, such that the clearance between the aspiration catheter 24 and the inner lumen 34 of the guide sheath 22 is decreased at one or more radial regions of the guide sheath 22. For example, the protuberance 58 may circumferentially extend 180 degrees around the catheter body 38, or the protuberance 58 may include diametrically opposed portions, each of which circumferentially extends 90 degrees around the catheter body 38. Although the aspiration catheter 24 is described and illustrated as having a discontinuity or multiple discontinuities 58 at a single lengthwise portion, it should be appreciated that the aspiration catheter 24 may have multiple discontinuities 58 along the length of the catheter body 38. As will be described in further detail below, the aspiration catheter 24 may be translated within the inner lumen 34 of the guide sheath 22, such that the location of the discontinuity 58 (and thus the reduced clearance) may be dynamically associated with a selected lengthwise portion of the guide sheath 22, the distal advancement of which through a bend in the vasculature V of the patient P has been hindered due to the buildup of static friction.

[96] In an alternative embodiment illustrated in Fig. 7, instead of, or in addition to, the aspiration catheter 24 having one or more discontinuities, the guide sheath 22 may comprise an optional discontinuity 58’ disposed in the inner lumen 34, each of which decreases a clearance between the aspiration catheter 24 and the inner lumen 34 of the guide sheath 22; that is, from the nominal clearance illustrated in Fig. 8B to the decreased clearance illustrated in Fig. 8A. In the illustrated embodiment, the discontinuity 58 takes the form of a protuberance radially extending inward from the sheath body 28, although the discontinuity 58’ may take the form of any feature that abruptly decreases the clearance between the aspiration catheter 24 and the inner lumen 34 of the guide sheath 22. Furthermore, although the protuberance 58’ radially extends around the inner lumen 34 of the guide sheath 22 in a continuous manner, the protuberance 58’ may alternatively have one or more radial cuts or grooves, such that the clearance between the aspiration catheter 24 and the inner lumen 34 of the guide sheath 22 is decreased at one or more radial regions of the guide sheath 22. For example, the protuberance 58’ may circumferentially extend 180 degrees around the inner lumen 34 of the guide sheath 22, or the protuberance 58’ may include diametrically opposed portions, each of which circumferentially extends 90 degrees around the inner lumen 34 of the guide sheath 22. As will be described in further detail below, the guide sheath 22 may be designed to associate the discontinuity 58’ (and thus the reduced clearance) with a selected lengthwise portion of the guide sheath 22, the distal advancement of which through a bend in the vasculature V of the patient P is anticipated to be hindered due to the buildup of static friction. [97] In an optional embodiment, rather than incorporating discontinuity(ies) into the guide sheath 22 or the aspiration catheter 24, as illustrated in Figs. 5 and 6A-6B or Figs. 7 and 8A-8B, a discontinuity or discontinuities may be incorporated into a dedicated elongate device that may be snugly inserted into the inner lumen 34 of the guide sheath 22 during navigation of the guide sheath 22 within the vasculature V of the patient P. In this manner, the guide sheath 22 and/or aspiration catheter 24 may be conventional without concern that discontinuities may adversely affect their respective functionalities.

[98] For example, referring to Fig. 9 and 10, an obturator 27 may be inserted into the inner lumen 34 of the guide sheath 22. The dedicated obturator 27 is profiled, and in particular, comprises an obturator body 29 having a larger diameter distal section 31 and a smaller diameter proximal section 33 immediately adjacent the distal section 31 , such that a discontinuity 58” (in this case, an angled ledge) is formed on the dedicated obturator body 29 between the distal section 31 and the proximal section 33. In the illustrated embodiment, the dedicated obturator 27 further comprises an inner lumen 35 that extends entirely through the dedicated obturator body 29 for accommodating the guidewire 26.

[99] In the same manner that the discontinuity 58” decreases the clearance between the aspiration catheter 24 and the inner lumen 34 of the guide sheath 22 illustrated in Fig. 5, the discontinuity 58” likewise decreases a clearance between the dedicated obturator 27 and the inner lumen 34 of the guide sheath 22; that is, from the nominal clearance illustrated in Fig. 11 B to the decreased clearance illustrated in Fig. 11 A. Such discontinuity 58” enhances the navigational effect applied by the navigation assistance device 16 at a selected longitudinal region of the guide sheath 22. The dedicated obturator 27 may be arranged in the inner lumen 34 of the guide sheath 22, such that there is a relatively high clearance between the dedicated obturator 27 and the inner lumen 34 at the proximal end of the guide sheath 22, and a relatively low clearance between the dedicated obturator 27 and the inner lumen 34 at the distal end of the guide sheath 22, thereby defining the region of vibrating or wiggling influence from the proximal adapter 36 to the more distal region of the guide sheath 22.

[100] In an alternative embodiment, the proximal section 33 comprises outer ridges 37 (shown in Fig. 11C) that that extend lengthwise along the outside of the obturator body 29, such that the proximal section 33 has an outer periphery (or envelope) 39 that is co-extensive with the outer surface of the distal section 31. Such outer ridges 37 are arranged around the circumference of the proximal section 33. In the illustrated embodiment, the proximal section 33 is provided with five outer ridges 37, although in other embodiments, the proximal section 33 may be provided with any suitable number of outer ridges 37. In this manner, a number (in this case five) discontinuities radially extend around the dedicated obturator 27 between the distal section 31 and the proximal section 33, thereby decreasing clearance between the aspiration catheter 24 and the inner lumen 34 of the guide sheath 22 at multiple radial regions of the guide sheath 22.

[101] Although the dedicated obturator 27 is described and illustrated as having a discontinuity or multiple discontinuities 58” at a single lengthwise portion of the obturator body 27, it should be appreciated that the dedicated obturator 27 may have multiple discontinuities 58” along the length of the obturator body 27. As will be described in further detail below, the dedicated obturator 27 may be translated within the inner lumen 34 of the guide sheath 22, such that the location of the discontinuity 58” (and thus the reduced clearance) may be dynamically associated with a selected lengthwise portion of the guide sheath 22, the distal advancement of which through a bend in the vasculature V of the patient P has been hindered due to the buildup of static friction.

[102] Furthermore, although the dedicated obturator 27 has been described as having the discontinuity or discontinuities 58”, in an alternative embodiment, instead of, or in addition to, a dedicated obturator having one or more discontinuities, the guide sheath 22 may comprise an optional discontinuity disposed in the inner lumen 34 (similar to the discontinuity 58’ illustrated in Figs. 7 and 8A-8B), each of which decreases a clearance between the dedicated obturator and the inner lumen 34 of the guide sheath 22. In this case, the dedicated obturator 27 may simple be a tube having a uniform diameter along its length.

[103] Although the coaxial catheter assembly 12 has been respectively described as a guide sheath 22, aspiration catheter 24, and guidewire 26, it should be appreciated that the coaxial catheter assembly 12 may comprise any number or type of elongate intravascular devices 26. For example, in an alternative embodiment, the working catheter 24 may be a delivery catheter, and the elongate intravascular device 26 may be a delivery wire for delivering a vaso-occlusive device through the delivery catheter. As another example, the first elongate intravascular device 22 or the second elongate intravascular device 24 may be a balloon catheter for providing flow assisted navigation (“sailing”) through the vasculature V of the patient P and/or for performing angioplasty and/or contrast procedures (for enhanced visualization or flow diagnostics) within the vasculature V of the patient P.

[104] Referring back to Fig. 1 , the pressurized fluid source 14 may be, e.g., a reservoir containing fluid at a baseline elevated pressure above the mean arterial pressure (MAP) of the patient. As will be discussed in further detail below, the baseline elevated pressure will prevent backflow of blood through the navigation assistance device 16. The navigation assistance device 16 is configured for oscillating the fluid pressure within the inner lumen 34 of the guide sheath 22 (in this case, oscillating the baseline elevated pressure) at a suitable frequency (e.g., in the range of 0.1 Hz-100Hz, and preferably in the range of 0.5Hz-50Hz), thereby mechanically vibrating the guide sheath 22. In this manner, the mechanical vibrations in the guide sheath 22 prevent or break any buildup in static friction at the lengthwise portion of the guide sheath 22 as it is navigated through bends within the vasculature V of the patient P, as will be described in further detail below. In the optional case where the aspiration catheter 24 has one or more discontinuities 58 (as illustrated in Figs. 5 and 6A-6B) or the guide sheath 22 has one or more discontinuities 58’ (as illustrated in Figs. 7 and 8A-8B), disposition of the aspiration catheter 24 within the inner lumen 34 of the guide sheath 22 will enhance the mechanical vibrations induced within the guide sheath 22 via the navigation assistance device 16.

[105] Although the navigation assistance device 16 is described and illustrated as oscillating the fluid pressure within the inner lumen 34 of the guide sheath 22 to induce mechanical vibrations within the guide sheath 22, thereby facilitating its navigation within the vasculature V of the patient P, it should be appreciated that the navigation assistance device 16 may be designed to oscillate the fluid pressure within an inner lumen of any elongate intravascular device, such as, e.g., the aspiration lumen 44 of the aspiration catheter 24, to induce mechanical vibrations within the aspiration catheter 24 to facilitate its navigation within the vasculature V of the patient P. In this case, the mechanical vibrations induced within the aspiration catheter 24 may be optionally enhanced by incorporating one or more discontinuities into the guidewire 26 (e.g., in the same manner that discontinuities 58 are incorporated into the aspiration catheter 24 illustrated in Figs. 5 and 6A-6B), and/or one or more discontinuities may be incorporated into the aspiration lumen 44 of the aspiration catheter 24 (e.g., in the same manner that discontinuities 58 may be incorporated into the inner lumen 34 of the guide sheath 22 illustrated in Figs. 7 and 8A-8B), and/or using a dedicated obturator (e.g., the obturator 27 illustrated in Figs. 9-10 and 11A-11C) sized to snugly fit within the aspiration lumen 44 of the aspiration catheter 24. In the illustrated embodiment, the navigation assistance device 16 is used to navigate a lumened elongate intravascular device (in this case, the guide sheath 22, or alternatively, the aspiration catheter 24) within the bare vasculature V of a patient P, although in some cases, the navigation assistance device 16 may be used to navigate a lumened elongate intravascular device within another lumened elongate intravascular device that has been previously introduced within the vasculature V of the patient P (e.g., the aspiration catheter 24 within the guide sheath 22).

[106] In the embodiment illustrated in Fig. 1 , the navigation assistance device 16 generally comprises a user/data input device (e.g., a user interface (Ul)) 60, a controller 62, a pressure manifold 64, a fluid pressure oscillator 66, and a fluid refill control element 68.

[107] The III 60 can take the form of a control panel (e.g., with a display, buttons, keypad, touchscreen, microphone configured to receive voice commands, or the like) and provides user input to the controller 62 for toggling the navigation assistance device 16 on and off, generating a desired pressure waveform, etc. The controller 62 provides power and logistical control to the navigation assistance device 16 and may take the form of, e.g., a microcontroller, for receiving input from the III 60 and controlling the fluid pressure oscillator 66 (described in further detail below) in accordance with the user input (e.g., changing operational modes or selecting pressure waveforms). Such pressure waveforms may be simple, e.g., purely sinusoidal or may be complex, may comprise a combination of different complex components, including rectangular components, sinusoidal components, cut-sine components, and random components. Such pressure waveforms may be cyclical, non-cyclical, random, musical, or chaotic. In fact, such pressure waveforms may be arbitrary in that navigation assistance device 16 may be programmed (e.g., preprogrammed during manufacture, programmed during subsequent system upgrades, programmed by the user, etc.) to generate any pressure waveform having a desired shape, desired frequency spectrum, desired duty cycle, desired amplitude, desired midpoint, etc. or the navigation assistance device 16 may customize such programed pressure waveforms to a particular scenario. The pressure waveform generated by the navigation assistance device 16 may be arbitrary in that any conceivable pressure waveform may be envisioned. Furthermore, the navigation assistance device 16 may cycle through a multitude of different pressure waveforms.

[108] The pressure manifold 64 may have RHV functionality in that it prevents backflow of blood through the inner lumen 34 of the guide sheath 22 via the application of the baseline elevated pressure supplied by the pressurized fluid source 14 the pressure manifold 64, while allowing rotation of the aspiration catheter 24 (or alternatively, the guidewire 26) within the inner lumen 34 of the guide sheath 22.

[109] In particular, the pressure manifold 64 comprises a manifold cavity 70, a distal pressure port 72 configured for fluidly coupling the inner lumen 34 of the guide sheath 22 to the manifold cavity 70, a vent inlet 74 (which may take the form of a female luer lock fitting) configured for fluidly coupling the pressurized fluid source 14 to a pressure chamber (described in further detail below) of the manifold cavity 70, thereby allowing the pressurized fluid source to apply a baseline elevated pressure to the pressure chamber. The pressure manifold 64 may be coupled to the guide sheath 22 and pressurized fluid source 14 via the use of connectors (not shown) or may alternatively be integrated with the guide sheath 22 and pressurized fluid source 14 without the use of connectors.

[110] The pressure manifold 64 has a built-in RHV. In particular, the pressure manifold 64 further comprises a guide tube 76 disposed within the manifold cavity 70. The guide tube 76 comprises a tube lumen 78 disposed in-line with and fluidly coupled to the distal pressure port 72. The pressure manifold 64 further comprises a proximal port 80 disposed in-line with and mechanically coupled to the tube lumen 78, such that the aspiration catheter 24 and/or guide wire 26 may be advanced within the tube lumen 78 in a coaxial relationship with the guide sheath 22. The guide tube 76 further comprises at least one tube opening 82 that fluidly couples the tube lumen 78 to the manifold cavity 70, such that the manifold cavity 70 is in fluid communication with the distal pressure port 72, and thus, the inner lumen 34 of the guide sheath 22, via the tube opening(s) 82 and tube lumen 78. In the illustrated embodiment, the sidewall of the guide tube 76 is perforated with a plurality of tube openings 82 to maximize fluid communication between the manifold cavity 70 and the distal pressure port 72. The tube lumen 78 is sealed to prevent backflow of blood therethrough. In particular, the pressure manifold 64 further comprises a distal rotating luer connector 84 configured for being affixed to the guide sheath 22 (via the proximal adapter 36) and placed inline with the distal end of the guide tube 76, such that the distal pressure port 72 may be placed in fluid communication with the tube lumen 78. The pressure manifold 64 further comprises a proximal compression seal 86 (e.g., a Tuohy-Borst valve) placed in-line with the proximal end of the guide tube 76 to prevent proximal fluid loss (e.g., blood) out of the pressure manifold 64.

[111] The fluid pressure oscillator 66 is configured for oscillating a variable volume of pressure oscillating fluid with the manifold cavity 70 (i.e., alternately increasing and decreasing the variable volume of pressure oscillating fluid) within the manifold cavity 70 in accordance with the waveform signal output by the controller 62. That is, increasing the variable volume of pressure oscillating fluid in the of the manifold cavity 70 via the fluid pressure oscillator 66 correspondingly decreases the pressure in the manifold cavity 70, while decreasing the variable volume of pressure oscillating fluid in the pressure chamber of the manifold cavity 70 via the fluid pressure oscillator 66 correspondingly increases the pressure in the manifold cavity 70. As a result of oscillating the variable volume of pressure oscillating fluid within the manifold cavity 70, the fluid pressure within the tube lumen 78 oscillates via fluid communication between the tube opening(s) 82 and the manifold cavity 70, thereby oscillating the fluid pressure within the inner lumen 34 of the guide sheath 22, which mechanically vibrates (or “wiggles”) the guide sheath 22.

[112] In the illustrated embodiment, the fluid pressure oscillator 66 comprises a pressure transduction element 88, an actuator 90, and a driver 92. The pressure transduction element 88 directly interfaces with the variable volume of pressure oscillating fluid in the manifold cavity 70 (and in particular, within a pressure chamber of the manifold cavity 70, as will be discussed in further detail below), and is configured for being physically moved to oscillate such variable volume of fluid, thereby converting mechanical energy into fluid energy. The actuator 90 is configured for being operably coupled to the pressure transduction element 88, and in particular, is configured for physically moving the pressure transduction element 88 in an oscillatory manner. As will be described in further detail below, the pressure transduction element 88 may advantageously comprise a movable manifold boundary (such as, e.g., a diaphragm) affixed within the manifold cavity 70, while the actuator may comprise, e.g., voice coil actuator, motor, rotary to linear cam, solenoid, audio exciter, peristaltic pump, rotary vane, gear, screw, syringe, pneumatic piston, pneumatic pulse generator, etc. [113] The driver 92 is configured for controlling the actuator 90 in accordance with the modulated pressure waveform signal output by the controller 62 to physically move the pressure transduction element 88 in a manner that oscillates the variable volume of pressure oscillating fluid within the manifold cavity 70. In the illustrated embodiment, the controller 62 may control the driver 92 in an open-loop manner, but in alternative embodiments, the controller 62 may control the driver 92 using closed loop feedback, e.g., by sensing fluid pressure in the manifold cavity 70 or inner lumen 34 of guide sheath 22, as will be described in further detail below.

[114] In one embodiment, the driver 92 is electrical in nature (i.e., the driver 92 electrically drives the actuator 90 (e.g. , if the actuator 90 takes the form of a voice coil), although in alternative embodiments, the driver 92 may drive the actuator 90 using other forms of energy, including electromagnetic, pneumatic, hydraulic, etc. The driver 92 may comprise a waveform generator and actuator controller capable of controlling the fluid pressure oscillator 66 in a very precise manner.

[115] Although the controller 62 and driver 92 are described herein as being separate components, it should be appreciated that portions or all functionality of the controller and driver 92 may be performed by a single component. Furthermore, although all of the functionality of the controller 62 is described herein as being performed by a single component, and likewise all of the functionality of the driver 92 is described herein as being performed by a single component, such functionality each of the controller 62 and driver 92 may be distributed amongst several components. For example, the control functions may be performed by a separate controller, while the processing functions may be performed by a separate processor. It should be appreciated that those skilled in the art are familiar with the terms “controller” and “driver” and that they may be implemented in software, firmware, hardware, or any suitable combination thereof.

[116] The fluid refill control element 68 is configured for selectively fluidly coupling the pressurized fluid source 14 via the vent inlet 74 to the manifold cavity 70 to maintain the working variable volume of pressure oscillating fluid (or fluid pressure) of the manifold cavity 70 at a desired mean value (in this case, the baseline elevated pressure supplied by the pressurized fluid source 14), and thus, a desired mean fluid pressure within the manifold cavity 70. In particular, the amount of fluid exiting the manifold cavity 70 may be greater than the amount of fluid entering the manifold cavity 70, thereby reducing the average volume of pressure oscillating fluid, and thus the fluid pressure within, the manifold cavity 70, due to excess fluid withdrawal from the manifold cavity 70. However, the fluid refill control element 68 periodically or continuously injects small amounts of pressure oscillating fluid from the pressurized fluid source 14 into the manifold cavity 70 via the vent inlet 74 to maintain a desired mean volume of pressure oscillating fluid, and thus the desired mean fluid pressure within, the manifold cavity 70.

[117] In the illustrated embodiment, the fluid refill control element 68 comprises a check valve in fluid communication between the pressurized fluid source 14 and the vent inlet 74, such that, when a fluid pressure within the manifold cavity 70 drops below a threshold fluid pressure (and in this case, the fluid pressure of the pressurized fluid source 14), the check valve opens, thereby allowing pressure oscillating fluid to be conveyed from the pressurized fluid source 14 into the manifold cavity 70. In this manner, the average designed fluid pressure in the manifold cavity 70 (preferably, a pressure above the blood pressure of the patient P) may be maintained despite the loss of pressure oscillating fluid from the manifold cavity 70 out through the inner lumen 34 of the guide sheath 22 that prevents the backflow of blood through the inner lumen 34 of the guide sheath 22. When the fluid pressure within the manifold cavity 70 rises above a fluid pressure of the pressurized fluid source 14, the check valve closes, thereby preventing pressure oscillating fluid from being conveyed from the manifold cavity 70 into the pressurized fluid source 14.

[118] In an optional embodiment, the fluid refill control element 68 comprises a constant pressure system (not shown) that can be used to provide consistent pressure to the manifold cavity 70 via passive or active pressure regulation means, such as a pressure regulator, or a pressure bladder or pressure bubble, to eliminate system performance discrepancies among different facilities located at different altitudes, and thus, having different absolute atmospheric pressures. Thus, the constant pressure system enables the fluid refill control element 68 to supply a constant atmosphere- pressure-equivalized pressure oscillating fluid to the manifold cavity 70, thereby enabling the fluid pressure oscillator 66 to precisely generate the desired modulated pressure waveform that is essential to the effectiveness of the aspiration. In an optional embodiment, the navigation assistance device 16 further comprises one or more over-pressure relief valves (not shown) configured for release pressure from the manifold cavity 70 if the fluid pressure within the manifold cavity 70 exceeds a maximum threshold limit. [119] In an optional embodiment wherein the guide sheath 22 has balloon inflation or contrast delivery functionality, fluid (e.g., contrast agent) may be introduced through the fluid refill control element 68 from the pressurized fluid source 14 and into the vent inlet 74, such that the fluid flows through the manifold cavity 70 and through the inner lumen 34 of the guide sheath 22.

[120] Referring now to Figs. 12A-12C, one specific embodiment of a navigation assistance device 16a will be described. The navigation assistance device 16a comprises a single casing or housing 94 carrying the Ul 60, controller 62, pressure manifold 64, and a fluid pressure oscillator 66a. In the illustrated embodiment, the casing 94 is a two-part casing that comprises a top casing portion 94a and a bottom casing portion 94b that are removably coupled to each other to facilitate reuse of a portion of the navigation assistance device 16a, as will be discussed in further detail below. The controller 62 and driver 92 of the fluid pressure oscillator 66a are contained within the top casing portion 94a, while the Ul 60 is affixed to the exterior of the top casing portion 94a. The bottom casing portion 94b, at least in part, forms the pressure manifold 64, with the manifold cavity 70 being formed within the bottom casing portion 94b, and the distal pressure port 72 and vent inlet 74 along with the fluid refill control element 68, being affixed to the bottom casing portion 94b in fluid communication with the manifold cavity 70. The guide tube 76, along with the distal rotating luer connector 84 and proximal compression seal 86, are disposed within the bottom casing portion 94b, with the tube lumen 78 being in fluid communication with the manifold cavity 70 via the openings 82 formed through the sidewall of the guide tube 76. Because the control functions are performed by the componentry in the top casing portion 94a, and the working functions are performed by the componentry in the bottom casing portion 94b, the top casing portion 94a may be considered a master unit, while the bottom casing portion 94b may be considered a slave unit. Other embodiments of master and slave units will be discussed further below.

[121] In the embodiment illustrated in Figs. 12A-12C, the fluid pressure oscillator 66a takes the form of a direct drive diaphragm assembly. In particular, the fluid pressure oscillator 66a comprises a pressure transduction element 88a that takes the form of a movable manifold boundary (and in particular a diaphragm) that divides the manifold cavity 70 between a pressure chamber 70a containing a variable volume of pressure oscillating fluid 96 in fluid communication with the distal pressure port 72 and vent inlet 74, and a working chamber 70b that is fluidly isolated from the distal pressure port 72 and vent inlet 74. The pressure chamber 70a of the manifold cavity 70 is bounded by a bottom wall 98 and sidewall 100 of the bottom casing portion 94b and the opposing diaphragm 88a. Thus, it can be appreciated that the diaphragm 88a sterilely seals the working chamber 70b of the manifold cavity 70 from the pressure oscillating fluid 96 contained in the pressure chamber 70a of the manifold cavity 70, thereby preventing cross-contamination between the pressure chamber 70a and the working chamber 70b.

[122] The fluid pressure oscillator 66a further comprises a linear actuator 90a comprising an actuator housing 102 (e.g., a voice coil) and a rod 104 directly mechanically coupled to the diaphragm 88a via a coupling 106, such that the diaphragm 88a may be alternately flexed from a nominal state of flex away from the actuator housing 102 and towards the bottom wall 98 of the casing 94 to reciprocatably oscillate the variable volume of pressure oscillating fluid 96, and thus the fluid pressure within, the manifold cavity 70. The actuator housing 102 is contained within the top casing portion 94a, while the rod 104 is disposed in the bottom casing portion 94b.

[123] As illustrated in Fig. 12A, the rod 104 is in a nominal position relative to the actuator housing 102, such that the diaphragm 88a is in a nominal flex state relative to the bottom wall 98 of the casing 94, and the pressure chamber 70a has a nominal volume of pressure oscillating fluid 96 at a nominal fluid pressure (in this case, a baseline elevated pressure above the blood pressure of the patient P). As illustrated in Fig. 12B, when the rod 104 is linearly translated from its nominal position away from the actuator housing 102 (downward as shown by the arrow), the diaphragm 88a is flexed from its nominal flex state towards the bottom wall 98 of the casing 94, thereby decreasing the volume of pressure oscillating fluid 96, and thus correspondingly increasing the fluid pressure from the nominal fluid pressure, in the pressure chamber 70a. In contrast, as illustrated in Fig. 9C, when the rod 104 is linearly translated from its nominal position towards the actuator housing 102 (upward as shown by the arrow), the diaphragm 88a is flexed from its nominal flex state away the bottom wall 98 of the casing 94, thereby increasing the volume of pressure oscillating fluid 96, and thus correspondingly decreasing the fluid pressure from nominal fluid pressure, in the pressure chamber 70a.

[124] In one advantageous embodiment, the coupling 106 removably couples the rod 104 to the diaphragm 88a, such that the actuator 90a, including the rod 104, may be easily decoupled from the diaphragm 88a. For example, the coupling 106 can be a screw, clasp mechanism, slotted insert coupling, snapped fitting, pinned union, magnetic holding, threaded union, or any other mechanism that can be quickly manipulated to decouple the rod 104 of the actuator 90a from the diaphragm 88a. As discussed above, the top casing portion 94a carries the more expensive components (in this case, the electronics) of the navigation assistance device 16a, including the Ul 60, controller 62, actuator 90a, and driver 92, while the bottom casing portion 94b carries the less expensive components (in this case, passive components), including the diaphragm 88a, pressure port 72, and vent inlet 74 (along with the fluid refill control element 68), and guide tube 76 (along with the distal rotating luer connector 84 and proximal compression seal 86).

[125] Because the bottom casing portion 94b is removably coupled to the top casing portion 94a, while the rod 104 of the actuator 90a is removably coupled to the diaphragm 88a, the top casing portion 94a, along with its contents, can be made to be reusable, while the bottom casing portion 94b, along with its contents, can be made to be disposable. That is, after use, the bottom casing portion 94b, including the diaphragm 88a, the distal pressure port 72, and vent inlet 74 (and fluid refill control element 68), can be removed from the top casing portion 94a and discarded, and replaced with a new bottom casing portion 94b, including a new diaphragm 88a, pressure port 72, and vent inlet 74 (and fluid refill control element 68), for subsequent use.

[126] Alternatively, the bottom casing portion 94b, including its contents, can be removed from the top casing portion 94a, re-sterilized, and re-affixed to the top casing portion 94a. In this manner, the top casing portion 94a, along with the more sensitive electronic components (which have been sterilely isolated from the pressure oscillating fluid 96 contained in the sterile bottom casing portion 94b via the diaphragm 88a) need not be sterilized, thereby preventing thermal damage to the electronic components and/or obviating the need to design more expensive electronic componentry that can withstand one or more thermal cycles used during a typical sterilization procedure.

[127] Although the navigation assistance device 16a has been described as comprising a fluid pressure oscillator 66a that takes the form of a direct drive diaphragm assembly, it should be appreciated that alternative embodiments of navigation assistance devices may comprise a fluid pressure oscillator that takes the form of an indirect drive diaphragm assembly or a pneumatically or hydraulically driven diaphragm assembly having high-pressure and low-pressure valves that are alternately opened and closed, as described in copending U.S. Provisional Application Ser. No. xx/xxx,xxx, entitled “Fluid Pressure Oscillator Driven Dynamic Pressure Aspiration Device” (Attorney Docket No. 23-007 PR1 ), which is expressly incorporated herein by reference. Furthermore, although the navigation assistance device 16a has been described as comprising a single fluid pressure oscillator 66a, alternative embodiments of navigation assistance devices may comprise multiple fluid pressure oscillators, e.g., a pair of fluid pressure oscillators, as described in copending U.S. Provisional Application Ser. No. xx/xxx,xxx, entitled “Fluid Pressure Oscillator Driven Dynamic Pressure Aspiration Device” (Attorney Docket No. 23-007 PR1 ), which has been expressly incorporated herein by reference.

[128] Referring now to Figs. 13A-13C, another specific embodiment of a navigation assistance device 16b will be described. The navigation assistance device 16b generally comprises a master unit 108, a slave unit 1 10, and flexible fluidic tubing 112 fluidly coupling the slave unit 110 to the master unit 108.

[129] The master unit 108 is similar to the navigation assistance device 16a illustrated in Figs. 12A-12C, with the exception that the master unit 108 does not contain a pressure manifold having a pressure port and vent inlet. Instead, the master unit 108 comprises a cavity 70’ having a primary pressure chamber 70a’ and an output pressure port 114’ in fluid communication with the primary pressure chamber 70a’ and to which one end of the flexible fluidic tubing 112 is affixed. The slave unit 110 takes the form of a separate pressure manifold having a secondary pressure chamber 70a” and an input pressure port 114” in fluid communication with the secondary pressure chamber 70a” and to which the other end of the flexible fluidic tubing 112 is affixed. The pressure manifold 64 also has the distal pressure port 72 and vent inlet 74 (with fluidic tubing) along with the fluid refill control element 68.

[130] Like the navigation assistance device 16a, the master unit 108 comprises a casing or housing 94’ containing the controller 62, and on which the Ul 60 is affixed, while the slave unit 110 comprises a casing or housing 94” forming the pressure manifold 64 having the secondary pressure chamber 70a”, along with the distal pressure port 72, vent inlet 74, and fluid refill control element 68. In the illustrated embodiment, the casing 94’ of the master unit 108 is a two-part casing that comprises a top casing portion 94a and a bottom casing portion 94b that are removably coupled to each other. As will be described in further detail below, the entire master unit 108 may be reusable, while the entire slave unit 110 may be disposable. [131] In the embodiment illustrated in Figs. 13A-13C, the navigation assistance device 16b comprises a fluid pressure oscillator 66b that takes the form of a two-part drive diaphragm assembly. In particular, the fluid pressure oscillator 66b comprises a primary pressure transduction element 88b that takes the form of a diaphragm affixed within the cavity 70’ of the master unit 108, and a secondary pressure transduction element 88c that also takes the form of a diaphragm affixed within the manifold cavity 70” of the slave unit 110. The diaphragm 88b divides the cavity 70’ of the master unit 108 between the primary pressure chamber 70a’ containing a variable volume of primary pressure oscillating fluid 96’ in fluid communication with the output pressure port 114’, and a primary working chamber 70b’ fluidly isolated from the output pressure port 114’. The primary pressure chamber 70a’ of the cavity 70’ is bounded by a bottom wall 98’ and sidewall 100’ of the casing 94’ and opposing diaphragm 88b.

[132] The diaphragm 88c divides the manifold cavity 70” of the slave unit 110 between a secondary pressure chamber 70a” containing a variable volume of secondary pressure oscillating fluid 96” in fluid communication with the distal pressure port 72 and vent inlet 74, and a secondary working chamber 70b” containing primary pressure oscillating fluid 96’ fluidly isolated from the distal pressure port 72 and vent inlet 74. Thus, it can be appreciated that the diaphragm 88c sterilely seals the primary pressure oscillating fluid 96’ contained in the primary pressure chamber 70a’ of master unit 108, the fluidic tubing 112, and the secondary working chamber 70b” of the slave unit 110, from the secondary pressure oscillating fluid 96” contained in the secondary pressure chamber 70a” of the slave unit 110, thereby preventing cross-contamination between the secondary pressure chamber 70a” and the primary pressure chamber 70a’, fluidic tubing 112, and secondary working chamber 70b”. A sterile covering (not shown) may be used to encase the master unit 108, so that the entire navigation assistance device 16 may be used in the sterile field.

[133] The fluid pressure oscillator 66b further comprises the linear actuator 90a comprising the actuator housing 102 (e.g., a voice coil) and the rod 104 directly mechanically coupled to the diaphragm 88b via the coupling 106. The actuator housing 102 is contained within the top casing portion 94a, while the rod 104 is disposed in the bottom casing portion 94b. The diaphragm 88b of the master unit 108 is fluidly coupled to the diaphragm 88c of the slave unit 110 via the primary pressure oscillating fluid 96’ contained in the primary pressure chamber 70a’ of the master unit 108, and the primary pressure oscillating fluid 96’ contained in the fluidic tubing 1 12 and secondary working chamber 70b” of the slave unit 1 10.

[134] Thus, by reciprocatably moving the rod 104 from its nominal position away and towards the actuator housing 102, the diaphragm 88a may be reciprocatably flexed from its nominal flex state towards and away from the bottom wall 98 of the casing 94’ of the master unit 108 to reciprocatably oscillate the volume of primary pressure oscillating fluid 96’, and thus the fluid pressure within, the primary pressure chamber 70a’ of the master unit 108. In turn, the volume of primary pressure oscillating fluid 96’, and thus the fluid pressure within, the working chamber 70b” of the slave unit 110 may be reciprocatably oscillated, thereby reciprocatably flexing the diaphragm 88a from its nominal flex state towards and away from the bottom wall 98 of the casing 94” of the slave unit 110 to reciprocatably oscillate the volume of secondary pressure oscillating fluid 96”, and thus the fluid pressure within the secondary pressure chamber 70a” of the slave unit 110. Thus, in essence, fluid pulses are communicated from the master unit 108 to the slave unit 110 via the tubing 112.

[135] As illustrated in Fig. 13A, the rod 104 is in a nominal position relative to the actuator housing 102, such that the diaphragm 88b is in a nominal flex state relative to the bottom wall 98 of the casing 94’ of the master unit 108. Thus, the primary pressure chamber 70a’ of the master unit 108, and thus the working chamber 70b” of the slave unit 110, have a nominal volume of primary pressure oscillating fluid 96’ at a nominal pressure. Thus, the diaphragm 88c is in a nominal flex state relative to the bottom wall 98 of the casing 94” of the slave unit 110, such that the secondary pressure chamber 70a” of the slave unit 110 has a nominal volume of secondary pressure oscillating fluid 96” at a nominal pressure (in this case, at the baseline vacuum pressure).

[136] As illustrated in Fig. 13B, when the rod 104 is linearly translated from its nominal position away from the actuator housing 102 (downward as shown by the arrow), the diaphragm 88b is flexed from its nominal flex state towards the bottom wall 98 of the casing 94’ of the master unit 108, thereby decreasing the volume of primary pressure oscillating fluid 96’, and thus correspondingly increasing the fluid pressure from the baseline vacuum pressure, in the primary pressure chamber 70a’ of the master unit 108, fluidic tubing 112, and working chamber 70b” of the slave unit 110. In turn, the increased pressure of the primary pressure oscillating fluid 96’ within the working chamber 70b” of the slave unit 1 10 flexes the diaphragm 88c from its nominal flex state towards the bottom wall 98 of the casing 94” of the slave unit 110, thereby decreasing the variable volume of secondary pressure oscillating fluid 96” in the secondary pressure chamber 70a”, and thus correspondingly increasing the fluid pressure from the baseline vacuum pressure in the secondary pressure chamber 70a”.

[137] In contrast, as illustrated in Fig. 13C, when the rod 104 is linearly translated from its nominal position toward the actuator housing 102 (upward as shown by the arrow), the diaphragm 88b is flexed from its nominal flex state away from the bottom wall 98 of the casing 94’ of the master unit 108, thereby increasing the volume of primary pressure oscillating fluid 96’, and thus correspondingly decreasing the fluid pressure from the baseline vacuum pressure, in the primary pressure chamber 70a’ of the master unit 108, fluidic tubing 112, and working chamber 70b” of the slave unit 110. In turn, the decreased pressure of the primary pressure oscillating fluid 96’ within the working chamber 70b” of the slave unit 110 flexes the diaphragm 88c from its nominal flex state away from bottom wall 98 of the casing 94” of the slave unit 110, thereby increasing the variable volume of secondary pressure oscillating fluid 96” in the secondary pressure chamber 70a”, and thus correspondingly decreasing the fluid pressure from the baseline vacuum pressure in the secondary pressure chamber 70a”.

[138] Advantageously, the slave unit 110 is removably coupled to the master unit 108 via the fluidic tubing 112, such that the master unit 108 can be made to be reusable, while the slave unit 110 can be made to be disposable. That is, after use, the entire slave unit 110, along with the fluidic tubing 1 12, can be disconnected from the master unit 108 and discarded, and replaced with a new slave unit 110 and fluidic tubing 112 for subsequent use. Alternatively, the slave unit 110 can be disconnected from the master unit 108, re-sterilized, and reconnected to the master unit 108 via new fluidic tubing 112. In this manner, the master unit 108, along with the more sensitive electronic components (which have been sterilely isolated from the secondary pressure oscillating fluid 96” contained in the sterile secondary pressure chamber 70a” of the slave unit 110 via the diaphragm 88c need not be sterilized, thereby preventing thermal damage to the electronic components and/or obviating the need to design more expensive electronic componentry that can withstand one or more thermal cycles used during a typical sterilization procedure. Furthermore, the distribution of the electronic and mechanical components within the master unit 108 allows the size of the slave unit 110 to be decreased, thereby facilitating handling of the slave unit 110 by the surgeon. [139] Although the master unit 108 and slave unit 110 of the navigation assistance device 16b have been described as being hydraulically connected to each other via fluidic tubing, the master unit 108 and slave unit 110 may be pneumatically connected to each other (i.e. , the master unit 108 may have a pneumatic or hydraulic actuator, e.g., in the form of a valve system). Furthermore, although the fluidic components of the fluid pressure oscillator 66b are distributed between the master unit 108 and slave unit 110, in other embodiments, all of the fluidic and mechanical components of the navigation assistance device, e.g., the pressure transduction element 88 and actuator 90, as well as the pressure manifold 64, including the distal pressure port 72, RHV components, and vent inlet 74 (along with the fluid refill control element 68), may be contained within the slave unit 110, with the master unit 108 only containing electronic components of the navigation assistance device, e.g., the Ul 60, controller 62, and driver 92. One type of such navigation assistance device, which takes the form of an aspiration modulation device, is described in copending U.S. Provisional Application Ser. No. xx/xxx,xxx, entitled “Fluid Pressure Oscillator Driven Dynamic Pressure Aspiration Device” (Attorney Docket No. 23-007 PR1 ), which has been expressly incorporated herein by reference.

[140] Referring now to Fig. 14, another embodiment of a medical system 10’ constructed accordance with the disclosed inventions will now be described. The medical system 10’ is similar to the medical system 10 illustrated in Fig. 1 , with the exception that the medical system 10’ is capable of facilitating both navigation of aspiration catheter 24 and facilitating aspiration of a thrombus T by the aspiration catheter 24.

[141] In particular, the medical system 10’ generally comprises the aforementioned coaxial catheter assembly 12 and pressurized fluid source 14, a navigation assistance/aspiration device 16’, a vacuum source 18, an atmospheric pressure source 19, and an aspirate collection container 20.

[142] In operation, the vacuum source 18 provides a baseline vacuum pressure for the aspiration catheter 24. The base vacuum pressure is below the MAP of the patient, and preferably below atmospheric pressure, and thus, can be considered a vacuum capable of aspirating the thrombus T within the aspiration lumen 44 of the aspiration catheter 24. This baseline vacuum pressure may be controlled and adjusted as needed by the user for aspirating tissue. Over any given time period during a tissue removal procedure, the user may set the level of baseline vacuum pressure to be constant or may vary the vacuum level. The vacuum source 18 can be, e.g., conventional a pump (e.g., a rotary vane, diaphragm, peristaltic or Venturi pump) or a syringe, configured for generating a low pressure (i.e., a base vacuum pressure) within the aspiration lumen 44 of the aspiration catheter 24. The vacuum source 18 may comprise a regulator (not shown) for maintaining the output of the vacuum source 18 at a consistent level.

[143] The atmospheric fluid source 19 may be, e.g., a reservoir containing a liquid at atmospheric pressure, such as saline (e.g., a saline drip bag), or ambient air. In the illustrated embodiment, the medical system 10’ further comprises a valve 21 fluidly coupled between the pressurized fluid source 14 and atmospheric pressure source 19 and the navigation assistance/aspi ration device 16’. The valve 21 is configured for selectively fluidly coupling the pressurized fluid source 14 or the atmospheric pressure source 19 to the navigation assistance/aspiration device 16’. Alternatively, two check valves (not shown) having different cracking pressures can be fluidly coupled to the navigation assistance/aspiration device 16’ or a pressure regulator (not shown) can be fluidly coupled between a single fluid source and the navigation assistance/aspiration device 16’ for selectively providing a baseline elevated fluid pressure above the MAP of the patient or atmospheric fluid pressure to the navigation assistance/aspiration device 16’. The aspirate collection container 20 may be any suitable receptacle in fluid communication with the vacuum source 18 via an exhaust line for enabling collection and disposal of aspirated tissue in a sterile manner. Alternatively, the aspirate collection container 20 may be located between the vacuum source 18 and the aspiration catheter 24. A safety valve (not shown) may be provided within the aspirate collection container 20 to prevent fluid or material from entering the vacuum source 18.

[144] The navigation assistance/aspiration device 16’ is similar to the navigation assistance device 16 described above with respect to Fig. 1 , with the exception that the navigation assistance/aspiration device 16’ is additionally configured for being operated in both a navigation mode and a dynamic aspiration mode. In particular, in the navigation mode, the navigation assistance/aspiration device 16’, in the same manner as the navigation assistance device 16 described above with respect to Fig. 1 , is configured for oscillating the fluid pressure within the aspiration lumen 44 of the aspiration catheter 24 at a suitable frequency (e.g., in the range of 0.1 Hz-100Hz, and preferably in the range of 0.5Hz-50Hz), thereby mechanically vibrating the aspiration catheter 24, and facilitating navigation of the aspiration catheter 24 within the vasculature V of the patient P. In the optional case where the guidewire 26 has one or more discontinuities (in a similar manner that the aspiration catheter 24 has one or more discontinuities 58 illustrated in Figs. 5 and 6A-6B) or the aspiration catheter 24 has one or more discontinuities (in a similar manner that the guide sheath 22 has one or more discontinuities 58’ illustrated in Figs. 7 and 8A-8B), disposition of the guidewire 26 within the aspiration lumen 44 of the aspiration catheter 24 will enhance the mechanical vibrations induced within the aspiration catheter 24 via the navigation assistance device 16’.

[145] However, the navigation assistance/aspiration device 16’ additionally provides an interface between the aspiration catheter 24, vacuum source 18, and pressurized fluid source 14, such that during the dynamic aspiration mode, the navigation assistance/aspiration device 16’ modulates a vacuum pressure. In the illustrated embodiment, the navigation assistance/aspiration device 16’ modulates the vacuum pressure within the aspiration lumen 44 of the aspiration catheter 24 by modulating the baseline vacuum pressure applied by the vacuum source 18 to the aspiration catheter 24 (i.e., by oscillating the fluid pressure within the aspiration catheter 24 around the baseline vacuum pressure) at a suitable frequency (e.g., in the range of 1 Hz-20Hz).

[146] As a result of modulating the vacuum pressure (and in this case, the baseline vacuum pressure) within the aspiration lumen 44 of the aspiration catheter 24, ingestion of the thrombus T by the aspiration catheter 24 will be facilitated during no-flow or low-flow conditions (e.g., if the thrombus T clogs the aspiration lumen 44 of the aspiration catheter 24 or otherwise there is a flow anomaly in the aspiration circuit of the medical system 10’). Furthermore, by modulating the baseline vacuum pressure, the baseline vacuum pressure applied by the vacuum source 18 to the aspiration catheter 24 can be relatively low, such that blood loss and/or the occurrence of vessel collapse may be minimized during free-flow conditions (e.g., when the aspiration lumen 44 is not clogged and the aspiration circuit of the dynamic aspiration system 10’ is operating as intended). Furthermore, the navigation assistance device 16 may modulate the baseline vacuum pressure applied by the vacuum source 18 to the aspiration catheter 24 without using an excessive amount of saline, which may only be used to initially prime the medical system 10’. As a result, much of the material contained within the aspirate collection container 20 will be tissue removed from the patient, thereby allowing the nature and the amount of such tissue to be determined via a quick inspection of the tissue collection chamber 18. Furthermore, due to the employment of the navigation assistance/aspi ration device 16’ (described in further detail below), the vacuum source 18 may be operated at relatively low vacuum pressures (e.g., 30 to 60 kPa (absolute)/-70 to -40 kPa (gauge), which is higher in an absolute pressure sense than what is required for a valve-based system. Because the baseline vacuum pressure of the vacuum source 18 need not be strong, the vacuum source 18 may be lower performing or may even take the form of house vacuum lines. The vacuum source 18 may comprise a regulator (not shown) for maintaining the output of the vacuum source 18 at a consistent level.

[147] During operation in the dynamic aspiration mode, the navigation assistance/aspiration device 16’ modulates the baseline vacuum pressure applied by the vacuum source 18 to the aspiration catheter 24 by oscillating the fluid pressure within the aspiration catheter 24 around the baseline vacuum pressure). For example, as illustrated in Fig. 15, the navigation assistance/aspiration device 16’ may generate a therapeutic pressure waveform 200 that oscillates around the baseline vacuum pressure (i.e., the pressure drops below the baseline vacuum pressure, then rises above the baseline vacuum pressure, and in the illustrated case above vent pressure (i.e., the pressure of the pressurized fluid source 14), drops back below the baseline vacuum pressure, etc. Thus, in contrast to valve aspiration systems that may generate a pressure waveform that varies between the baseline vacuum pressure and the vent pressure (i.e., the maxima (peaks) of the pressure waveform is essentially the vent pressure, and the minima (valleys) of the pressure waveform is essentially the vacuum pressure), the maxima and minima of the therapeutic waveform 200 are independent of the baseline vacuum pressure and the vent pressure.

[148] It should be appreciated that, although maxima and minima of the therapeutic waveform 200 illustrated in Fig. 15 are equidistant relative to the baseline vacuum pressure (i.e., the minimum and maximum pressures are equally offset from the baseline vacuum pressure), the maxima and minima of the therapeutic waveform 200 may be non-equidistant relative to the baseline vacuum pressure (i.e., the maxima are offset from the baseline vacuum pressure a greater distance than the minima are offset from the baseline vacuum pressure, or vice versa). Furthermore, although the maxima of the therapeutic waveform 200 are higher than the vent pressure, it should be appreciated that the peaks of the therapeutic waveform 200 may be below the vent pressure. Furthermore, although the magnitudes of all the maxima and the magnitudes of all the minima of the therapeutic waveform 200 are uniform, the magnitudes of the maxima and/or the magnitudes of the minima of the therapeutic waveform 200 may be uniform. Preferably, the maxima of the therapeutic waveform 200 are below the mean arterial pressure (MAP) of the patient, so that any thrombus T that is captured by the aspiration catheter 24 is not ejected back out into the artery of the patient.

[149] The navigation assistance/aspiration device 16’ modulates the baseline vacuum pressure applied by the vacuum source 18 to the aspiration catheter 24 in a manner that accurately and precisely generates a desired modulated therapeutic pressure waveform at the distal end 42 of the catheter body 38. Such modulated therapeutic pressure waveform may be complex. For example, as illustrated in Fig. 15, the modulated therapeutic pressure waveform 200 comprises different complex components, including rectangular components 202, sinusoidal components 204, and cut-sine components 206. Of course, alternative modulated therapeutic pressure waveforms may be simple, e.g., may be purely sinusoidal, purely rectangular, etc. Indeed, as will be described in further detail below, the modulated therapeutic pressure waveform 200 may be arbitrary in that navigation assistance/aspiration device 16’ may be programmed (e.g., pre-programmed during manufacture, programmed during subsequent system upgrades, programmed by the user, etc.) to generate any modulated therapeutic pressure waveform 200 (therapeutic or diagnostic) having a desired shape, desired frequency, desired duty cycle, desired amplitude, desired midpoint, etc. or the navigation assistance/aspiration device 16’ may customize such programmed modulated therapeutic pressure waveform 200 to a diagnostic scenario.

[150] The navigation assistance/aspiration device 16’ is capable of accurately and precisely generating a desired modulated pressure waveform at the distal end 42 of the catheter body 38 using pressure feedback control. In particular, the navigation assistance/aspiration device 16’ may modulate the baseline vacuum pressure applied by the vacuum source 18 to the aspiration catheter 24, such that fluid pressure measured (directly or indirectly) at the distal end 42 of the catheter body 38 tracks the desired pressure waveform.

[151] Notably, the use of pressure feedback to generate a desired modulated pressure waveform in an aspiration catheter should be contrasted with aspiration systems that may modulate the baseline vacuum pressure in an open loop manner or using other feedback, such as positioning feedback (e.g., using an encoder or positioning sensor), which may be susceptible to decorrelation between controlled modulation of the baseline vacuum pressure and the desired pressure waveform at the distal end 42 of the catheter body 38 due to, e.g., air bubbles in the dynamic aspiration system, and may also have a relatively slow response time.

[152] In contrast, when using pressure feedback, the controlled modulation of the baseline vacuum pressure will be much more correlated to the fluid pressure at the distal end 42 of the catheter body 38, and may have a faster response time. Thus, the navigation assistance/aspi ration device 16’ may operate without actuator sensors that simplifies the feedback in closed-loop control, and further to allow quick response and high-modulation capability. Such an arrangement avoids controls related, load- induced, motion modulations in the medical system 10’, thereby enabling high-speed force/torque output for a more consistent modulated pressure waveform. For example, direct frequency/speed modulation, direct amplitude assigned pulsing, or programmable parametric inputs of a transfer function are all possible modes of operation when employing pressure feedback control.

[153] The navigation assistance/aspiration device 16’ may optionally perform an in situ diagnostic procedure during active aspiration by modulating an input pressure waveform (e.g., singlet pulses, frequency sweeps, or chirps), while simultaneously monitoring the pressure response to the modulated input pressure waveform, and/or may be operated to dynamically tune the medical system 10’ apriori (e.g., to prescreen the aspiration catheter 24, when connected to the navigation assistance/aspiration device 16’, but prior to its introduction into the patient), as described in copending U.S. Provisional Application Ser. No. xx/xxx,xxx, entitled “Fluid Pressure Oscillator Driven Dynamic Pressure Aspiration Device” (Attorney Docket No. 23-007 PR1 ), which has been expressly incorporated herein by reference.

[154] In the embodiment illustrated in Fig. 14, the navigation assistance/aspiration device 16’ generally comprises the aforementioned user/data input device Ul 60, a controller/processor 62’, a pressure manifold 64’, a sensor 114, a fluid pressure oscillator 66’, the aforementioned fluid refill control element 68, and a vacuum flow control element 116.

[155] In addition to receiving input from the Ul 60 and controlling the fluid pressure oscillator 66’ in accordance with the user input, as described above with respect to the controller 62, the controller/processor 62’ is configured for switching the operational mode of the navigation assistance/aspiration device 16’ between a navigation mode and a dynamic aspiration mode as directed by the physician via the III 60. During the navigation mode, the navigation assistance/aspiration device 16’ operates in the same manner as the navigation assistance device 16 described above with respect to Fig. 1. During the dynamic aspiration mode, the navigation assistance/aspiration device 16’ activates the vacuum source 18, and applies the dynamically modulated baseline vacuum pressure to the aspiration catheter 24 in accordance with the modulated therapeutic pressure waveform (e.g., the modulated therapeutic pressure waveform 200 illustrated in Fig. 12). Prior to operating the navigation assistance/aspiration device 16’ in the navigation mode, the controller/processor 62’ is configured for fluidly decoupling the vacuum source 18 from the pressure chamber 70 via a vacuum outlet (described below), and fluidly coupling the pressurized fluid source 14 to the pressure chamber 70 via the vent inlet 74 (via operation of the valve 21 ), and prior to operating the navigation assistance/aspiration device 16’ in the dynamic aspiration mode, the controller/processor 62’ is configured for fluidly coupling the vacuum source 18 to the pressure chamber 70 concurrently with fluidly coupling the atmospheric fluid source 19 to the pressure chamber 70 via the vent inlet 74 (via operation of the valve 21 ).

[156] During the operation of such dynamic aspiration mode, the controller/processor 62’ is configured for, in response to the measured parameter (indicative of the fluid pressure at the distal end 42 of the catheter body 38), dynamically modifying a waveform signal corresponding to the modulated therapeutic pressure waveform, and outputting the dynamically modified waveform signal. Such dynamic modification of the waveform signal facilitates tracking of the fluid pressure at the distal end 42 of the catheter body 38 to the desired modulated pressure waveform. The desired modulated pressure waveform may be arbitrary in that any conceivable modulated pressure waveform (including the modulated complex therapeutic pressure waveform 200 illustrated in Fig. 15) may be envisioned. The controller/processor 62’ may select such modulated therapeutic pressure waveform from a plurality of different modulated therapeutic pressure waveforms (e.g., stored in a library or look-up table) or the controller/processor 62’ may customize such modulated therapeutic pressure waveform. The controller/processor 62’ may communicate with the fluid pressure oscillator 66’ either through a wired connection or a wireless connection. The controller/processor 62’ may optionally comprise a battery (not shown). [157] The control ler/processor 62’ may also be configured for analyzing or interpreting pressure data derived from the parameter measured by the sensor 114 when performing the diagnostic procedure described above, and generating or selecting a desired modulated therapeutic pressure waveform. The controller/processor 62’ may implement any of the in situ or apriori diagnostic procedures discussed in U.S. Provisional Application Ser. No. xx/xxx,xxx, entitled “Fluid Pressure Oscillator Driven Dynamic Pressure Aspiration Device” (Attorney Docket No. 23-007 PR1 ), which has been expressly incorporated herein by reference.

[158] Although all of the functionality of the controller/processor 62’ is described herein as being performed by a single component, such functionality each of the controller/processor 62’ and driver 92 may be distributed amongst several components. For example, the control functions may be performed by a separate controller, while the processing functions may be performed by a separate processor. It should be appreciated that those skilled in the art are familiar with the term “processor” and that it may be implemented in software, firmware, hardware, or any suitable combination thereof.

[159] In addition to comprising the aforementioned manifold cavity 70, pressure port 72, and vent inlet 74, the pressure manifold 64’ further comprises a vacuum outlet 118 configured for fluidly coupling the vacuum source 18 (via the aspirate collection container 20) to the manifold cavity 70, thereby allowing the vacuum source 18 to apply a baseline vacuum pressure to the aspiration catheter 24 during operation of the navigation assistance/aspiration device 16’ in the dynamic aspiration mode. Furthermore, instead of the fluid refill control element 68 being directly fluidly coupled to the pressurized fluid source 14, the fluid refill control element 68 is indirectly fluidly coupled to the pressurized fluid source 14 and the atmospheric fluid source 19 via the valve 21. Like the pressure manifold 64 described above, the pressure manifold 64’ may be coupled to the aspiration catheter 24, vacuum source 18, and pressurized fluid source 14 via the use of connectors (not shown) or may alternatively be integrated with the aspiration catheter 24, vacuum source 18, pressurized fluid source 14, atmospheric fluid source 19, and valve 21 without the use of connectors.

[160] Like the aforementioned fluid pressure oscillator 66, the fluid pressure oscillator 66’ comprises the aforementioned pressure transduction element 88, actuator 90, and driver 92. However, in contrast to the aforementioned fluid pressure oscillator 66’, which is configured for oscillating the fluid pressure within the manifold cavity 70 in an absolute sense, the fluid pressure oscillator 66’ is configured for modulating the baseline vacuum pressure within the manifold cavity 70 (i.e., the fluid pressure in the manifold cavity 70 oscillates around the baseline vacuum pressure) during operation of the navigation assistance/aspiration device 16’ in the dynamic aspiration mode. That is, during operation of the navigation assistance/aspiration device 16’ in the dynamic aspiration mode, increasing the variable volume of pressure modulating fluid in the manifold cavity 70 via the fluid pressure oscillator 66’ correspondingly decreases the pressure in the manifold cavity 70 below the baseline vacuum pressure, while decreasing the variable volume pressure modulating fluid in the manifold cavity 70 via the fluid pressure oscillator 66’ correspondingly increases the pressure in the manifold cavity 70 above the baseline vacuum pressure. The variable volume of pressure modulating fluid within the manifold cavity 70 may be alternately increased and decreased in a global manner, such the fluid pressure alternately falls below and rises above the baseline vacuum pressure (e.g., to create the rectangular components 202 and sinusoidal components 204 of the therapeutic waveform 200 illustrated in Fig. 15), or in a local manner, such that the fluid pressure alternatively increases and decreases, but remains below the baseline vacuum pressure or remains above the baseline vacuum pressure (e.g., to create the cut-sine components 206 of the therapeutic waveform 200 illustrated in Fig. 15).

[161] As will be described in further detail below, the fluid pressure oscillator 66’ modulates the baseline vacuum pressure in accordance with the waveform signal that has been dynamically modified by the control ler/processor 62’ in response to the parameter measured by the sensor 114 (indicative of the fluid pressure at the distal end 42 of the catheter body 38), such that fluid pressure measured by the sensor 114 tracks the desired modulated pressure waveform; or alternatively, in accordance with a plurality of waveform signals corresponding to a plurality of different modulated diagnostic pressure waveform signals.

[162] The sensor 1 14 is configured for measuring a fluid pressure indicative of the fluid pressure at the distal end 42 of the catheter body 38 to provide fluid pressure feedback to the driver 92, such that the fluid pressure in the manifold cavity 70 may be directly controlled. Furthermore, because the fluid pressure in the manifold cavity 70 is directly controlled, the actuator 90 may utilize pure open loop position control. Optionally, one or more actuator sensors (e.g., position feedback sensors) may be initially employed to calibrate the actuator 90 (e.g., to determine the midpoint and upper and lower limits of the actuator 90), and then turned off after such calibration, after which open loop position control of the actuator 90, which enables a higher level of precision of the actuator 90 at higher frequencies, may be utilized.

[163] In one embodiment, the sensor 114 is a pressure sensor located in the distal end 42 of the catheter body 38, such that the fluid pressure in the distal end 42 of the catheter body 38 can be directly measured, or may be a pressure sensor located in the manifold cavity 70 or even in the fluid pressure oscillator 66’, such that the fluid pressure in the distal end 42 of the catheter body 38 can be indirectly measured or inferred from the fluid pressure measurements in the manifold cavity 70 or fluid pressure oscillator 66’. Alternatively, the sensor 114 may be a force feedback sensor that measures the output force of the actuator 90. The fluid pressure in the fluid pressure oscillator 66’ (e.g., in the manifold cavity 70), and thus by implication the fluid pressure at the distal end 42 of the catheter body 38, can be inferred based on the size of the actuator 90. For example, the fluid pressure in the manifold cavity 70 may be computed (e.g., by the controller/processor62’) based on the measured force (e.g., by dividing the measured force by a known area of the actuator 90 acting on the fluid pressure oscillator 66’).

[164] In one advantageous embodiment, the actuator 90 has an input fed by the driver 92 that is directly proportional to the output force of the actuator 90, and thus, the fluid pressure within the distal end 42 of the catheter body 38. In this case, the sensor 114 may take the form of a circuit that measures the magnitude of the electrical input (e.g., a current sensing circuit), thereby obviating the need for a separate sensor in the catheter body 38 or the manifold cavity 70.

[165] The employment of a sensor 114 that measures fluid pressure that is indicative of the fluid pressure at the distal end 42 of the catheter body 38 allows the fluid pressure oscillator 66’ to more precisely generate the desired pressure waveform at the distal end 42 of the catheter body 38, as discussed above. In an optional embodiment, the sensor 114 or another sensor may be employed to generate a fluid pressure profile that can be analyzed (e.g., by the driver 92) to sense system leaks, air plugs, siphon interruptions, pressure loss, and other issues.

[166] The vacuum flow control element 116 is configured for preventing backflow of blood/fluid from the aspirate collection container 20 into the manifold cavity 70. For example, the vacuum flow control element 1 16 may comprise minimal flow restriction one-way valve in fluid communication between the aspirate collection container 20 and the vacuum outlet 118, such that, when a fluid pressure within the pressure manifold 64’ drops below the baseline vacuum pressure (e.g., during the valleys of the therapeutic waveform 200 illustrated in Fig. 15), the one-way valve closes, thereby preventing fluid/blood from being conveyed from the aspirate collection container 20 into the manifold cavity 70.

[167] In an optional embodiment, the navigation assistance/aspi ration device 16’ further comprises one or more over-pressure relief valves (not shown) configured for releasing pressure from the manifold cavity 70 if the fluid pressure within the manifold cavity 70 exceeds a maximum threshold limit. In another optional embodiment, the navigation assistance/aspiration device 16’ further includes a means for regulating the baseline vacuum pressure (not shown) at the desired baseline vacuum pressure. In still another optional embodiment, the navigation assistance/aspiration device 16’ further comprises a barometric pressure sensor (not shown) configured for measuring the local barometric pressure (e.g., due to altitude changes or transient weather conditions), such that the vacuum source 18 may accordingly adjust the baseline vacuum pressure relative to the barometric pressure to maintain a desired pressure differential between the baseline vacuum pressure and the measured barometric pressure. In still another optional embodiment, the navigation assistance/aspiration device 16’ further includes a means for regulating the baseline vacuum pressure (not shown) at the desired baseline vacuum pressure.

[168] Referring now to Figs. 16A-16C, one specific embodiment of a navigation assistance/aspiration device 16a’ will be described. The navigation assistance/aspiration device 16a’ is similar to the navigation assistance device 16a illustrated in Figs. 12A-12C in that it comprises a two-part casing or housing 94’ comprising a top casing portion 94a and a bottom casing portion 94b that are removably coupled to each other. The controller/processor 62’ and driver 92 are contained within the top casing portion 94a, while the III 60 is affixed to the exterior of the top casing portion 94a. The bottom casing portion 94b, at least in part, forms the pressure manifold 64’, with the manifold cavity 70 being formed within the bottom casing portion 94b, and the distal pressure port 72, vent inlet 74 along with the fluid refill control element 68, and vacuum outlet 118 along with the vacuum flow control element 116, being affixed to the bottom casing portion 94b in fluid communication with the manifold cavity 70. The guide tube 76, along with the distal rotating luer connector 84 and proximal compression seal 86, are disposed within the bottom casing portion 94b, with the tube lumen 78 being in fluid communication with the manifold cavity 70 via the openings 82 formed through the sidewall of the guide tube 76. Because the control functions are performed by the componentry in the top casing portion 94a, and the working functions are performed by the componentry in the bottom casing portion 94b, the top casing portion 94a may be considered a master unit, while the bottom casing portion 94b may be considered a slave unit. Other embodiments of master and slave units will be discussed further below.

[169] The navigation assistance/aspiration device 16a’ is also similar to the navigation assistance device 16a illustrated in Figs. 12A-12C in that it comprises the fluid pressure oscillator 66a’, although other types of fluid pressure oscillators may be employed. During the navigation mode (i.e., when the controller/processor 62’ fluidly couples the pressurized fluid source 14 to the pressure chamber 70 via the vent inlet 74), the fluid pressure oscillator 66a’ operates in the same manner as the fluid pressure oscillator 66a described above with respect to Figs. 12A-12C in that it varies the fluid pressure in the pressure chamber 70a around baseline elevated pressure supplied by the pressurized fluid source 14. However, during the dynamic aspiration mode (i.e., when the controller/processor 62’ fluidly couples the vacuum source 18 to the pressure chamber 70 via the vacuum outlet 118), the fluid pressure oscillator 66a’ modulates the fluid pressure in the pressure chamber 70a around the baseline vacuum pressure applied by the vacuum source 18.

[170] In particular, as illustrated in Fig. 16A, the rod 104 is in a nominal position relative to the actuator housing 102, such that the diaphragm 88a is in a nominal flex state relative to the relative to the bottom wall 98 of the casing 94, and the pressure chamber 70a has a nominal volume of pressure oscillating fluid 96 at a nominal fluid pressure (in this case, baseline elevated pressure) during the navigation mode and the baseline vacuum pressure during the dynamic aspiration mode). As illustrated in Fig. 16B, when the rod 104 is linearly translated from its nominal position away from the actuator housing 102 (downward as shown by the arrow), the diaphragm 88a is flexed from its nominal flex state towards the bottom wall 98 of the casing 94, thereby decreasing the volume of pressure oscillating fluid 96, and thus correspondingly increasing the fluid pressure from the nominal fluid pressure (baseline elevated pressure during the navigation mode and the baseline vacuum pressure during the dynamic aspiration mode), in the pressure chamber 70a. In contrast, as illustrated in Fig. 16C, when the rod 104 is linearly translated from its nominal position towards the actuator housing 102 (upward as shown by the arrow), the diaphragm 88a is flexed from its nominal flex state away the bottom wall 98 of the casing 94, thereby increasing the volume of pressure oscillating fluid 96, and thus correspondingly decreasing the fluid pressure from the nominal fluid pressure (baseline elevated pressure during the navigation mode and the baseline vacuum pressure during the dynamic aspiration mode), in the pressure chamber 70a.

[171] In the same manner described above with respect to the navigation assistance device 16a illustrated in Figs. 16A-16C, the bottom casing portion 94b is removably coupled to the top casing portion 94a, while the rod 104 of the actuator 90a is removably coupled to the diaphragm 88a. Thus, the top casing portion 94a, along with its contents, can be made to be reusable, while the bottom casing portion 94b, along with its contents, can be made to be disposable, or alternatively, the bottom casing portion 94b, including its contents, can be removed from the top casing portion 94a, re-sterilized, and re-affixed to the top casing portion 94a.

[172] Referring now to Figs. 17A-17C, another specific embodiment of a navigation assistance/aspiration device 16b’ will be described. The navigation assistance/aspiration device 16b’ generally comprises a master unit 108’, a slave unit 110’, and flexible fluidic tubing 112’ fluidly coupling the slave unit 110’ to the master unit 108’. The master unit 108’ is similar to the master unit 108 of the navigation assistance device 16b illustrated in Figs. 16A-16C, with the exception that it contains the controller/processor 62’, rather than the controller 62, while the slave unit 110’ is similar to the slave unit 110 of the navigation assistance device 16b illustrated in Figs. 16A-16C, with the exception that slave unit 110’ additionally has the vacuum outlet 118 along with the vacuum flow control element 116. The navigation assistance/aspiration device 16b’ comprises a two-part fluid pressure oscillator 66b’ similar to the two-part fluid pressure oscillator 66b of navigation assistance device 16b illustrated in Figs. 16A-16C, with the exception that, in addition to oscillating the fluid pressure about the baseline elevated pressure supplied by the pressurized fluid source 14 during operation of the navigation assistance device 16b in the navigation mode, the two-part fluid pressure oscillator 66b’ modulates the fluid pressure about the baseline vacuum pressure during operation of the navigation assistance device 16b in the dynamic aspiration mode.

[173] In particular, as illustrated in Fig. 17A, the rod 104 is in a nominal position relative to the actuator housing 102, such that the diaphragm 88b is in a nominal flex state relative to the bottom wall 98 of the casing 94’ of the master unit 108. Thus, the primary pressure chamber 70a’ of the master unit 108’, and thus the working chamber 70b” of the slave unit 110’, have a nominal volume of primary pressure oscillating fluid 96’ at a nominal fluid pressure (baseline elevated pressure during the navigation mode and the baseline vacuum pressure during the dynamic aspiration mode). Thus, the diaphragm 88c is in a nominal flex state relative to the bottom wall 98 of the casing 94” of the slave unit 110’, such that the secondary pressure chamber 70a” of the slave unit 110’ has a nominal volume of secondary pressure oscillating fluid 96” at the nominal fluid pressure.

[174] As illustrated in Fig. 17B, when the rod 104 is linearly translated from its nominal position away from the actuator housing 102 (downward as shown by the arrow), the diaphragm 88b is flexed from its nominal flex state towards the bottom wall 98 of the casing 94’ of the master unit 108, thereby decreasing the volume of primary pressure oscillating fluid 96’, and thus correspondingly increasing the fluid pressure from the nominal fluid pressure (baseline elevated pressure during the navigation mode and the baseline vacuum pressure during the dynamic aspiration mode), in the primary pressure chamber 70a’ of the master unit 108, fluidic tubing 112, and working chamber 70b” of the slave unit 110. In turn, the increased pressure of the primary pressure oscillating fluid 96’ within the working chamber 70b” of the slave unit 110 flexes the diaphragm 88c from its nominal flex state towards the bottom wall 98 of the casing 94” of the slave unit 1 10, thereby decreasing the variable volume of secondary pressure oscillating fluid 96” in the secondary pressure chamber 70a”, and thus correspondingly increasing the fluid pressure from the nominal fluid pressure (baseline elevated pressure during the navigation mode and the baseline vacuum pressure during the dynamic aspiration mode) in the secondary pressure chamber 70a”.

[175] In contrast, as illustrated in Fig. 17C, when the rod 104 is linearly translated from its nominal position toward the actuator housing 102 (upward as shown by the arrow), the diaphragm 88b is flexed from its nominal flex state away from the bottom wall 98 of the casing 94’ of the master unit 108, thereby increasing the volume of primary pressure oscillating fluid 96’, and thus correspondingly decreasing the fluid pressure from the nominal fluid pressure (baseline elevated pressure during the navigation mode and the baseline vacuum pressure during the dynamic aspiration mode), in the primary pressure chamber 70a’ of the master unit 108, fluidic tubing 112, and working chamber 70b” of the slave unit 110. In turn, the decreased pressure of the primary pressure oscillating fluid 96’ within the working chamber 70b” of the slave unit 110 flexes the diaphragm 88c from its nominal flex state away from bottom wall 98 of the casing 94” of the slave unit 110, thereby increasing the variable volume of secondary pressure oscillating fluid 96” in the secondary pressure chamber 70a”, and thus correspondingly decreasing the fluid pressure from the nominal fluid pressure (baseline elevated pressure during the navigation mode and the baseline vacuum pressure during the dynamic aspiration mode) in the secondary pressure chamber 70a”.

[176] In the same manner that slave unit 110 is removably coupled to the master unit 108 via the fluidic tubing 112 of the navigation assistance device 16b, the slave unit 110’ may be removably coupled to the master unit 108’ via the fluidic tubing 112’, such that the master unit 108’ can be made to be reusable, while the slave unit 110’ can be made to be disposable or alternatively re-sterilized, and reconnected to the master unit 108’ via new fluidic tubing 112’.

[177] Referring now to Fig. 18, still another specific embodiment of a navigation assistance/aspiration device 16c’ will be described. The navigation assistance/aspiration device 16c’ is similar to the navigation/aspiration device 16a’ illustrated in Figs. 16A-16C, with the exception that the RHV functionality is provided by a separate conventional RHV 55. That is the RHV 55 is external to the pressure chamber 70a.

[178] Like the navigation/aspiration device 16a’, the navigation/aspiration device 16c’ comprises a single casing or housing carrying the Ul (not shown), controller (not shown), pressure manifold (only the distal pressure port 72, vent inlet 74, and vacuum outlet 118 shown), and fluid pressure oscillator (all not shown). However, unlike the navigation/aspiration device 16a’, the pressure manifold does not comprise an RHV, and thus, does not have RHV functionality, which is instead incorporated into the conventional RHV 55.

[179] The conventional RHV 55 comprises a guide tube 57 having a central lumen 59, a side arm 61 affixed to the guide tube 57 and having side lumen 63 in fluid communication with the central lumen 59 of the guide tube 57, a conventional male Touhy-Borst connector 65 rotatably affixed to the distal end of the guide tube 57, a seal 67 affixed to the proximal end of the guide tube 57, and a Luer connector 69 affixed to the side arm 61. The Touhy-Borst connector 65 may be mated to the proximal end 40 of the aspiration catheter 24, and in particular, the proximal adapter 46, such that the central lumen 59 of the guide tube 57, and thus, the side lumen 63 of the side arm 61 , is in fluid communication with the aspiration lumen 44 of the aspiration catheter 24. The Luer connector 69 may be mated to the distal pressure port 72 of the navigation/aspiration device 16c’, such that the fluid pressure oscillator of the navigation/aspiration device 16c’ (in particular, the pressure chamber) is fluidly coupled to the central lumen 59 of the guide tube 57 via the side lumen 63 of the side arm 61 , and thus, the aspiration lumen 44 of the aspiration catheter 24. For example, the Luer connector 69 may take the form of complementary Luer connector that mates with distal pressure port 72. The guidewire 26 may be inserted through the central lumen 59 of the guide tube 57. The seal 67 is configured for sealing fluid flow between the outer surface of the guide wire 26 and the inner surface of the guide tube 57.

[180] Referring to Figs. 19 and 20A-20F, one method 150 of navigating the working catheter 24 within the vasculature V to the target tissue site TS of the patient P, and performing a medical procedure (e.g., a therapeutic and/or diagnostic procedure) on the patient will now be described. In the method 150, the working catheter 24 is described as an aspiration catheter, with the medical procedure being an aspiration of a thrombus T at the target tissue site TS, although it should be appreciated that the working catheter 24 can be any catheter capable of performing a medical procedure on a patient.

[181] First, in a conventional manner, the guide sheath 22 is introduced into the bare vasculature V of the patient P, such that the distal end 32 of the guide sheath 22 is significantly proximal to the tissue target site TS (step 152) (see Fig. 20A), and the guidewire 26 is distally advanced through the inner lumen 34 (shown in Fig. 3) of the guide sheath 22 and navigated within the bare vasculature V of the patient P until the distal end 54 of the guidewire 26 is adjacent the target tissue site TS of the patient (step 154) (see Fig. 20B). Next, the guide sheath 22 is navigated within the bare vasculature V of patient P over the guidewire 22 (such that the guidewire 26 is disposed within the inner lumen 34 (shown in Fig. 3) of the guide sheath 22) until the distal end 32 is located adjacent to the target tissue site TS of the patient (step 156) (see Fig. 20C). While the guide sheath 22 is navigated within the bare vasculature V of the patient P to the target tissue site TS, the fluid pressure within the inner lumen 34 of the guide sheath 22 is oscillated (e.g., in the range of 0.1 Hz-100Hz, and preferably in the range of 0.5Hz-50Hz), thereby mechanically vibrating the guide sheath 22 (step 158) (see Fig. 20D). [182] Although the fluid pressure within the inner lumen 34 of the guide sheath 22 may be oscillated using any fluid pulsing device, it is preferred that the navigation assistance device 16 illustrated in Fig. 1 be employed to facilitate navigation of the guide sheath 22 within the bare vasculature V to the target tissue site TS of the patient P. For example, prior to pulsing the fluid pressure within the inner lumen 34 of the guide sheath 22, the guidewire 26 may be inserted through the tube lumen 78 of the guide tube 76 (e.g., by proximally threading the the proximal end 52 of the guidewire 26 into distal rotating luer connector 84, through the tube lumen 78, and out through the proximal compression seal 86), and the proximal end 30 of the guide sheath 22, and in particular, the proximal adapter 36, is coupled to the navigation assistance device 16 via the distal rotating luer connector 84. The navigation assistance device 16 may then be operated to oscillate the fluid pressure in the inner lumen 34 of the guide sheath 22, thereby mechanically vibrating the guide sheath 22 while it is navigated in the bare vasculature V of the patient P.

[183] In one method, the fluid pressure within the inner lumen 34 of the guide sheath 22 is oscillated continuously as the guide sheath 22 is navigated over the guidewire 26 within the bare vasculature V of the patient P, thereby preventing the buildup of static friction along any lengthwise portion of the guide sheath 22 that would otherwise hinder distal advancement of the lengthwise portion of the guide sheath 22 through a bend in the bare vasculature V of the patient P. In another method, the fluid pressure in the inner lumen 34 of the guide sheath 22 is only oscillated in response to the navigation of the guide sheath 22 within a bend in the bare vasculature V of the patient P that causes a buildup of static friction at a lengthwise portion of the guide sheath 22, thereby hindering distal advancement of the lengthwise portion of the guide sheath 22 through the bend in the bare vasculature V of the patient P. Thus, the mechanical vibration of the lengthwise portion of the guide sheath 22 resulting from the oscillation of the fluid pressure within the inner lumen 34 of the guide sheath 22 will release the buildup of static friction, thereby facilitating distal advancement of the lengthwise portion of the guide sheath 22 through the bend in the bare vasculature V of the patient P.

[184] If the aspiration catheter 24 and/or the inner lumen 34 of the guide sheath 22 has one or more discontinuities (as illustrated in Figs. 5 and 6A-6B or Figs. 7 and 8A-8B) or a dedicated obturator 27 having one or more discontinuities (as illustrated in Figs. 9-10 and 11A-11C) or no discontinuities (if the inner lumen 34 of the guide sheath 22 has a discontinuity or discontinuities) is provided, prior to oscillating the fluid pressure within the inner lumen 34 of the guide sheath 22, the aspiration catheter 24 or the dedicated obturator 27 may be distally advanced over the guidewire 26 (such that the guidewire 26 is disposed within the aspiration lumen 44 (shown in Fig. 3) of the aspiration catheter 24 or the guidewire lumen 35 of the dedicated obturator 27 (shown in Figs. 9-10 and 11A-11C) and through the inner lumen 34 of the guide sheath 22. In this manner, the magnitude of the mechanical vibration of the guide sheath 22 induced by the fluid pressure oscillation within the inner lumen 34 is increased at the discontinuity relative to the magnitude of the mechanical vibration of the guide sheath 22 away from the discontinuity (i.e. , the mechanical vibration of the guide sheath 22 is more focused at the discontinuity).

[185] If the aspiration catheter 24 or dedicated obturator 27, itself, has the discontinuity 58, the aspiration catheter 24 or dedicated obturator 27 may be translated within the inner lumen 34 of the guide catheter 22, such that the discontinuity 58 is within the lengthwise portion of the guide sheath 22 at which static friction is anticipated to build up (if the fluid pressure in the inner lumen 34 of the guide sheath 22 is continually oscillated) or has built up (if the fluid pressure in the inner lumen 34 of the guide sheath 22 is oscillated in response to such static friction buildup). Location of the discontinuity 58 on the aspiration catheter 24 or dedicated obturator 27 within the proper lengthwise portion of the guide sheath 22 may be facilitated by matching a radiopaque marker associated with the discontinuity 58 with such lengthwise portion of the guide sheath 22. If the guide sheath 22, itself, has the discontinuity 58, such discontinuity 58 may be located at the lengthwise portion (e.g., the distal end) of the guide sheath 22 anticipated to have the most buildup of static friction when navigated into a bend in the bare vasculature V of the patient P.

[186] After the distal end 32 of the guide sheath 22 is located adjacent the target tissue site TS, the aspiration catheter 24 may be distally advanced over the guidewire 26 (such that the guidewire 26 is disposed within the aspiration lumen 44 (shown in Fig. 3) of the aspiration catheter 24), into the inner lumen 34 (if not already within the guide sheath 22), through the inner lumen 34 of the guide sheath 22, and out of the guide sheath 22 until the operative element (in this case, the distal aspiration port 48) of the aspiration catheter 24 is located adjacent to the target tissue site TS of the patient P (step 160) (see Fig. 20E). Alternatively, the guidewire 26 may be completely removed from the inner lumen 34 of the guide sheath 22, and then the aspiration catheter 24 may simply be distally advanced into and through the inner lumen 34 of the guide sheath 22. Lastly, the guide wire 26 is removed from the aspiration lumen 44 of the aspiration catheter 24 (step 162) (see Fig. 20F), and a medical procedure, and in particular, the thrombus T is aspirated into the distal aspiration port 48 and through the aspiration lumen 44 of the aspiration catheter 24, is conventionally performed (step 164) (see Fig. 20G).

[187] Referring to Figs. 21 and 22A-22F, another method 180 of navigating the working catheter 24 within the vasculature V to the target tissue site TS of the patient P, and performing a medical procedure (e.g., a therapeutic and/or diagnostic procedure) on the patient will now be described. In the same manner as in the method 150, the working catheter 24 is an aspiration catheter, with the medical procedure being an aspiration of a thrombus T at the target tissue site TS. The method 180 is similar to the method 150, with the exception that the guide sheath 22 is not navigated within the bare vasculature V of the patient P all the way until the target tissue site TS. Rather, the aspiration catheter 24 is navigated distally past the guide sheath 22 within the bare vasculature V of the patient P to the target tissue site TS.

[188] First, in a conventional manner, the guide sheath 22 is introduced into the bare vasculature V of the patient P, such that the distal end 32 of the guide sheath 22 is significantly proximal to the tissue target site TS (step 182) (see Fig. 22A), and the guidewire 26 is distally advanced through the inner lumen 34 (shown in Fig. 3) of the guide sheath 22 and navigated within the bare vasculature V of the patient P until the distal end 54 of the guidewire 26 is adjacent the target tissue site TS of the patient (step 184) (see Fig. 22B). The aspiration catheter 24 is then distally advanced over the guidewire 26 (such that the guidewire 26 is disposed within the aspiration lumen 44 (shown in Fig. 3) of the aspiration catheter 24 into the inner lumen 34, through the inner lumen 34 of the guide sheath 22, and out of the guide sheath 22 until the operative element (in this case, the distal aspiration port 48) of the aspiration catheter 24 is located in the bare vasculature V of the patient P (step 186) (see Fig. 22C).

[189] Next, the aspiration catheter 24 is navigated within the bare vasculature V of patient P over the guidewire 22 until the distal aspiration port 48 is located adjacent to the target tissue site TS of the patient P (step 188) (see Fig. 22D). While the aspiration catheter 24 is navigated within the bare vasculature V of the patient P to the target tissue site TS, the fluid pressure within the aspiration lumen 44 of the aspiration catheter 24 is oscillated (e.g., in the range of 0.1 Hz-100Hz, and preferably in the range of 0.5Hz-50Hz), thereby mechanically vibrating the aspiration catheter 24 (step 190) (see Fig. 22E).

[190] Although the fluid pressure within the aspiration lumen 44 of the aspiration catheter 24 may be oscillated using any fluid pulsing device, it is preferred that the navigation assistance device 16 illustrated in Fig. 1 or the navigation assistance/aspiration device 16’ illustrated in Fig. 14 be employed to facilitate navigation of the aspiration catheter 24 within the bare vasculature V to the target tissue site TS of the patient P. For example, prior to pulsing the fluid pressure within the aspiration lumen 44 of the aspiration catheter 24, the guidewire 26 may be inserted through the tube lumen 78 of the guide tube 76 (e.g., by proximally threading the the proximal end 52 of the guidewire 26 into distal rotating luer connector 84, through the tube lumen 78, and out through the proximal compression seal 86), and the proximal end 40 of the aspiration catheter 24, and in particular, the proximal adapter 46, is coupled to the navigation assistance device 16 or the navigation assistance/aspiration device 16’ via the distal rotating luer connector 84. The navigation assistance device 16 may then be operated or the navigation assistance/aspiration device 16’ in the navigation mode (i.e., without vacuum) to oscillate the fluid pressure in the aspiration lumen 44 of the aspiration catheter 24, thereby mechanically vibrating the aspiration catheter 24 while it is navigated in the bare vasculature V of the patient P.

[191] In one method, the fluid pressure within the aspiration lumen 44 of the aspiration catheter 24 is oscillated continuously as the aspiration catheter 24 is navigated over the guidewire 26 within the bare vasculature V of the patient P, thereby preventing the buildup of static friction along any lengthwise portion of the aspiration catheter 24 that would otherwise hinder distal advancement of the lengthwise portion of the aspiration catheter 24 through a bend in the bare vasculature V of the patient P. In another method, the fluid pressure in the aspiration lumen 44 of the aspiration catheter 24 is only oscillated in response to the navigation of the aspiration catheter 24 within a bend in the bare vasculature V of the patient P that causes a buildup of static friction at a lengthwise portion of the aspiration catheter 24, thereby hindering distal advancement of the lengthwise portion of the aspiration catheter 24 through the bend in the bare vasculature V of the patient P. Thus, the mechanical vibration of the lengthwise portion of the aspiration catheter 24 resulting from the oscillation of the fluid pressure within the aspiration lumen 44 of the aspiration catheter 24 will release the buildup of static friction, thereby facilitating distal advancement of the lengthwise portion of the lengthwise portion of the aspiration catheter 24 through the bend in the bare vasculature V of the patient P.

[192] If the guide wire 26 and/or the aspiration lumen 44 of the aspiration catheter 24 has one or more discontinuities, the magnitude of the mechanical vibration of the aspiration catheter 24 induced by the fluid pressure oscillation within the aspiration lumen 44 is increased at the discontinuity relative to the magnitude of the mechanical vibration of the aspiration catheter 24 away from the discontinuity (i.e., the mechanical vibration of the aspiration catheter 24 is more focused at the discontinuity).

[193] If the guide wire 26, itself, has the discontinuity, the guide wire 26 may be translated within the aspiration lumen 44 of the aspiration catheter 24, such that the discontinuity is within the lengthwise portion of the aspiration catheter 24 at which static friction is anticipated to build up (if the fluid pressure in the aspiration lumen 44 of the aspiration catheter 24 is continually oscillated) or has built up (if the fluid pressure in the aspiration lumen 44 of the aspiration catheter 24 is oscillated in response to such static friction buildup). Location of the discontinuity on the guide wire 26 within the proper lengthwise portion of the aspiration catheter 24 may be facilitated by matching a radiopaque marker associated with the discontinuity with such lengthwise portion of the aspiration catheter 24. If the aspiration catheter 24, itself, has the discontinuity, such discontinuity may be located at the lengthwise portion (e.g., the distal end) of the aspiration catheter 24 anticipated to have the most buildup of static friction when navigated into a bend in the vasculature V of the patient P.

[194] The guide wire 26 is removed from the aspiration lumen 44 of the aspiration catheter 24 (step 192) (see Fig. 22F). Lastly, while the aspiration catheter 24 is adjacent the target tissue site TS, the fluid pressure within the aspiration lumen 44 of the aspiration catheter 24 is oscillated (e.g., in the range of 1 Hz-20Hz), thereby aspirating the thrombus T into the distal aspiration port 48 and through the aspiration lumen 44 of the aspiration catheter 24 (step 190) (see Fig. 22E). Although aspiration may be accomplished with a conventional aspiration system that dynamically loads (e.g., using a valving system) the fluid pressure in the aspiration catheter 24, aspiration is preferably accomplished using the navigation assistance/aspiration device 16’ illustrated in Fig. 14, e.g., by operating the navigation assistance/aspiration device 16’ in the dynamic aspiration mode (i.e., with vacuum to establish a baseline vacuum pressure in the aspiration lumen 44 of the aspiration catheter 24), thereby dynamically loading the thrombus T to facilitate its aspiration into the distal aspiration port 48 of the aspiration catheter 24.

[195] Although particular embodiments have been shown and described herein, it will be understood by those skilled in the art that they are not intended to limit the disclosed inventions, and it will be obvious to those skilled in the art that various changes, permutations, and modifications may be made (e.g., the dimensions of various parts, combinations of parts) without departing from the scope of the disclosed inventions, which is to be defined only by the following claims and their equivalents. The specification and drawings are, accordingly, to be regarded in an illustrative rather than restrictive sense. The various embodiments shown and described herein are intended to cover alternatives, modifications, and equivalents of the disclosed inventions, which may be included within the scope of the appended claims.

NUMBERED EMBODIMENTS OF THE INVENTION

1 . A navigation assistance device for use with an outer elongate intravascular device having a device lumen and an inner elongate intravascular device disposed within the device lumen , comprising: a pressure chamber; a rotary hemostasis valve (RHV) configured fluidly coupling the pressure chamber to the device lumen and for allowing passage of the inner elongate intravascular device therethrough; and a fluid pressure oscillator configured for oscillating a fluid pressure in the pressure chamber, such that a fluid pressure within the device lumen is oscillated, thereby mechanically vibrating the outer elongate intravascular device.

2. The navigation assistance device of embodiment 1 , wherein the RHV comprises: a guide tube having a tube lumen configured for allowing passage of the inner elongate intravascular device therethrough, wherein the tube lumen is sealed to prevent backflow of blood therethrough; and a connector rotatably affixed to a distal end of the guide tube, the connector configured for being coupled to a proximal end of outer elongate intravascular device, such that the tube lumen is in fluid communication with the device lumen.

3. The navigation assistance device of embodiment 2, further comprising a pressure manifold comprising: the pressure chamber; the guide tube, wherein the guide tube is disposed within the pressure chamber and has at least one tube opening fluidly coupling the pressure chamber to the tube lumen; and a distal pressure port configured for fluidly coupling the tube lumen to the device lumen when the connector is coupled to the proximal end of the outer elongate intravascular device; wherein the fluid pressure oscillator is configured for oscillating a fluid pressure in the pressure chamber, such that a fluid pressure within the tube lumen is oscillated via the at least one tube opening.

4. The navigation assistance device of embodiment 3, wherein the at least one tube opening comprises a plurality of tube openings formed through a wall of the guide tube.

5. The navigation assistance device of embodiment 2, wherein the RHV is external to the pressure chamber, the RHV further comprising a side arm affixed to the guide tube, the side arm having a side arm lumen in fluid communication with the tube lumen, wherein the pressure chamber is configured for being in fluid communication with the tube lumen via the side arm lumen.

6. The navigation assistance device of any of embodiments 1-5, wherein the pressure chamber is configured for having a variable volume of pressure oscillating fluid, and the fluid pressure oscillator is configured for oscillating the variable volume of fluid within the pressure chamber.

7. The navigation assistance device of embodiment 6, further comprising a vent inlet configured for fluidly coupling a pressurized fluid source having a baseline elevated pressure to the pressure chamber, and wherein the fluid pressure oscillator is configured for oscillating the fluid pressure in the pressure chamber by oscillating the fluid pressure around the baseline elevated pressure.

8. The navigation assistance device of embodiment 7, wherein the navigation assistance device further comprises a fluid refill control element configured for selectively fluidly coupling the pressurized fluid source to the pressure chamber.

9. The navigation assistance device of embodiment 8, wherein, when a fluid pressure within the pressure chamber drops below a threshold fluid pressure, the fluid refill control element is configured for conveying fluid from the pressurized fluid source into the pressure chamber. 10. The navigation assistance device of any of embodiments 1-9, wherein the fluid pressure oscillator is configured for oscillating the fluid pressure in the pressure chamber at a frequency in the range of 0.1 Hz-100Hz.

11. The navigation assistance device of embodiment 1 , wherein the fluid pressure oscillator is configured for oscillating the fluid pressure in the pressure chamber at a frequency in the range of 0.5Hz-50Hz.

12. An intravascular medical system, comprising; the navigation assistance device of any of embodiments 1-11 ; the outer elongate intravascular device; and the inner elongate intravascular device.

13. The intravascular medical system of embodiment 12, wherein the outer elongate intravascular device is a guide sheath, and the inner elongate intravascular device is a working catheter.

14. The intravascular medical system of embodiment 12, wherein the outer elongate intravascular device is a working catheter, and the inner elongate intravascular device is a guide wire.

15. The intravascular medical system of any of embodiments 12-14, wherein at least one of the outer elongate intravascular device and another elongate intravascular device configured for insertion into the inner lumen of the outer elongate intravascular device comprises a discontinuity that decreases a clearance between the other elongate intravascular device and the device lumen, such that a magnitude of the mechanical vibration is increased at the discontinuity.

16. The intravascular medical system of embodiment 15, wherein the other elongate intravascular device is the inner elongate intravascular device.

17. The intravascular medical system of embodiment 15, wherein the other elongate intravascular device is a dedicated obturator.

18. A method of using the navigation assistance device of embodiment 1 , comprising: introducing the outer elongate intravascular device within a vasculature of a patient; coupling the navigation assistance device to a proximal end of the outer elongate intravascular device; passing the inner elongate intravascular device through the tube lumen; introducing the inner elongate intravascular device into the device lumen; navigating the outer elongate intravascular device within the vasculature of the patient to a target tissue site; and operating the fluid pressure oscillator, thereby mechanically vibrating the outer elongate intravascular device as the outer elongate intravascular device is navigated within the vasculature of the patient to the target tissue site.

19. The method of embodiment 18, wherein the fluid pressure oscillator is continually operated as the outer elongate intravascular device is navigated within the vasculature of the patient to the target tissue site, such that a buildup of static friction at a lengthwise portion of the outer elongate intravascular device through a bend in the vasculature is prevented that would otherwise hinder distal advancement of the lengthwise portion of the outer elongate intravascular device through the bend in the vasculature.

20. The method of embodiment 18, wherein navigation of the outer elongate intravascular device within a bend in the vasculature of the patient causes a buildup of static friction at a lengthwise portion of the outer elongate intravascular device, thereby hindering distal advancement of the lengthwise portion of the outer elongate intravascular device through the bend, and wherein the fluid pressure oscillator is operated as the lengthwise portion of the outer elongate intravascular device is disposed within the bend, thereby releasing the buildup of static friction and facilitating distal advancement of the lengthwise portion of the outer elongate intravascular device through the bend in the vasculature of the patient.

21. The method of any of embodiments 18-20, wherein the outer elongate intravascular device is a guide sheath, and the inner elongate intravascular device is one of a working catheter and a guide wire.

22. The method of any of embodiments 18-20, wherein the inner elongate intravascular device is a guide wire, the method further comprising navigating the guide wire within the vasculature of the patient to the target tissue site, wherein the outer elongate intravascular device is navigated within the vasculature of the patient over the guide wire to the target tissue site while the guide wire is at the target tissue site.

23. The method of any of embodiments 18-20, wherein one of the outer elongate intravascular device and the inner elongate intravascular device is a working catheter having an operative element, the method further comprising operating the operative element to perform a medical procedure at the target tissue site. 24. The method of embodiment 23, wherein the patient has a thrombus at the target tissue site, the working catheter is an aspiration catheter, the operative element is a distal aspiration port, and the medical procedure comprising aspirating the thrombus within the distal aspiration port.

25. The method of any of embodiments 18-24, wherein the fluid pressure oscillator is operated as the aspiration catheter is navigated within the vasculature of the patient to the target tissue site at a frequency in the range of 0.1 Hz-100Hz.

26. A navigation assistance/aspiration device for use with an aspiration catheter having an aspiration lumen and a distal aspiration port, comprising: a pressure manifold comprising: a pressure chamber; a distal pressure port configured for fluidly coupling the aspiration catheter to the pressure chamber; a vent inlet configured for fluidly coupling a pressurized fluid source to the pressure chamber, thereby allowing the pressurized fluid source to apply a baseline elevated pressure to the pressure chamber; a vacuum outlet configured for fluidly coupling a vacuum source to the pressure chamber, thereby allowing the vacuum source to apply a baseline vacuum pressure to the pressure chamber; a controller configured for selectively fluidly coupling the pressurized fluid source to the pressure chamber via the vent inlet or fluidly coupling the vacuum source to the pressure chamber via the vacuum outlet; a fluid pressure oscillator configured for oscillating a fluid pressure within the pressure chamber, such that the baseline elevated pressure within the pressure chamber is modulated when the controller fluidly couples the pressurized fluid source to the pressure chamber via the vent inlet, and the baseline vacuum pressure within the pressure chamber is modulated when the controller fluidly couples the vacuum source to the pressure chamber.

27. The navigation assistance/aspiration device of embodiment 26, wherein the baseline elevated pressure is above the mean arterial pressure (MAP) of a patient.

28. The navigation assistance/aspiration device of embodiment 27, wherein the vent inlet is further configured for fluidly coupling an atmospheric fluid source to the pressure chamber, and the controller is further configured for selectively fluidly coupling the atmospheric fluid source to the pressure chamber via the vent inlet concurrently with fluidly coupling the vacuum source to the pressure chamber via the vacuum outlet.

29. The navigation assistance/aspiration device of embodiment 28, further comprising a fluid refill control element configured for conveying fluid from the pressurized fluid source into the pressure chamber when a fluid pressure within the pressure chamber drops below a threshold fluid pressure.

30. The navigation assistance/aspiration device of embodiment 28, further comprising means for selectively fluidly coupling the pressurized fluid source or the atmospheric pressure source to the vent inlet.

31. The navigation assistance/aspiration device of any of embodiment 26-30, further comprising a rotary hemostasis valve (RHV) fluidly coupling the pressure chamber to the aspiration lumen of the aspiration catheter.

32. The navigation assistance/aspiration device of embodiment 31 , wherein the RHV comprises: a guide tube having a tube lumen configured for allowing passage of a guide wire therethrough, and wherein the tube lumen is sealed to prevent backflow of blood therethrough; and a connector rotatably affixed to a distal end of the guide tube, the connector configured for being coupled to a proximal end of the aspiration catheter, such that the tube lumen is in fluid communication with the aspiration lumen.

33. The navigation assistance/aspiration device of embodiment 32, wherein the pressure manifold further comprises the guide tube, wherein the guide tube is disposed within the pressure chamber and has at least one tube opening fluidly coupling the pressure chamber to the tube lumen, wherein the distal pressure port is configured for fluidly coupling the tube lumen to the device lumen when the connector is coupled to the proximal end of the aspiration catheter, wherein the fluid pressure oscillator is configured for oscillating a fluid pressure in the pressure chamber, such that a fluid pressure within the tube lumen is oscillated via the at least one tube opening.

34. The navigation assistance/aspiration device of embodiment 33, wherein the at least one tube opening comprises a plurality of tube openings formed through a wall of the guide tube.

35. The navigation assistance/aspiration device of embodiment 32, wherein the RHV is external to the pressure chamber, the RHV further comprising a side arm affixed to the guide tube, the side arm having a side arm lumen in fluid communication with the tube lumen, wherein the pressure chamber is configured for being in fluid communication with the tube lumen via the side arm lumen.

36. The navigation assistance/aspiration device of any of embodiments 26-35, wherein the pressure chamber is configured for having a variable volume of pressure oscillating fluid, and the fluid pressure oscillator is configured for oscillating the variable volume of fluid within the pressure chamber.

37. The navigation assistance/aspiration device of any of embodiment 26-36, wherein the controller is further configured for outputting a waveform signal corresponding to a modulated therapeutic pressure waveform, wherein the fluid pressure oscillator is configured for oscillating the variable volume of the pressure modulating fluid within the pressure chamber in accordance with the waveform signal, thereby modulating the baseline vacuum pressure.

38. The navigation assistance/aspiration device of any of embodiments 26-37, further comprising a sensor configured for measuring a parameter indicative of a fluid pressure at the distal end of the aspiration catheter, wherein the controller is configured for, in response to the measured parameter, dynamically modifying the waveform signal, and wherein the fluid pressure oscillator is configured for oscillating the variable volume of the pressure modulating fluid within the pressure chamber in accordance with the dynamically modified waveform signal, such that the fluid pressure at the distal end of the aspiration catheter tracks a desired modulated pressure waveform.

39. The navigation assistance/aspiration device of any of embodiments 26-38, wherein the fluid pressure oscillator is configured for oscillating the fluid pressure in the pressure chamber at a frequency in the range of 0.1 Hz-100Hz when the pressurized fluid source is fluidly coupled to the pressure chamber, and for oscillating the fluid pressure in the pressure chamber at a frequency in the range of 1 Hz-20Hz when the vacuum source is fluidly coupled to the pressure chamber.

40. An intravascular medical system, comprising; the navigation assistance/aspiration device of embodiment 26; the aspiration catheter; and a guide wire for insertion into the aspiration lumen.

41. The intravascular medical system of embodiment 40, wherein at least one of the aspiration catheter and an elongate intravascular device is configured for insertion into the aspiration lumen comprises a discontinuity that decreases a clearance between the elongate intravascular device and the aspiration lumen, such that a magnitude of the mechanical vibration is increased at the discontinuity.

42. The intravascular medical system of embodiment 41 , wherein the elongate intravascular device is the guide wire.

43. The intravascular medical system of embodiment 41 , wherein the other elongate intravascular device is a dedicated obturator.

44. A method of using the navigation assistance/aspi ration device of embodiment 26, comprising: introducing the aspiration catheter within a vasculature of a patient; coupling the navigation assistance/aspiration device to a proximal end of aspiration catheter; navigating the aspiration catheter within the vasculature of the patient to a target tissue site; operating the fluid pressure oscillator, thereby mechanically vibrating the aspiration catheter as the aspiration catheter is navigated within the vasculature of the patient to the target tissue site; and operating the fluid pressure oscillator when the aspiration catheter is at the target tissue site, thereby aspirating the thrombus into the distal aspiration port and through the aspiration lumen.

45. The method of embodiment 44, further comprising: fluidly coupling the pressurized fluid source to the pressure chamber when the aspiration catheter is navigated within the vasculature of the patient to the target tissue site, and fluidly coupling the vacuum source to the pressure chamber when the aspiration catheter is aspirating the thrombus through the aspiration lumen.

46. The method of embodiment 44 or embodiment 45, wherein the fluid pressure oscillator is continually operated as the aspiration catheter is navigated within the vasculature of the patient to the target tissue site, such that a buildup of static friction at a lengthwise portion of the aspiration catheter through a bend in the vasculature is prevented that would otherwise hinder distal advancement of the lengthwise portion of the aspiration catheter through the bend in the vasculature.

47. The method of embodiment 44 or embodiment 45, wherein navigation of the aspiration catheter within a bend in the vasculature of the patient causes a buildup of static friction at a lengthwise portion of the aspiration catheter, thereby hindering distal advancement of the lengthwise portion of the aspiration catheter through the bend, and wherein the fluid pressure oscillator is operated as the lengthwise portion of the aspiration catheter is disposed within the bend, thereby releasing the buildup of static friction and facilitating distal advancement of the lengthwise portion of the aspiration catheter through the bend in the vasculature of the patient.

48. The method of any of embodiments 44-47, further comprising: navigating a guide wire within the vasculature of the patient to the target tissue site, wherein the aspiration catheter is navigated within the vasculature of the patient over the guide wire to the target tissue site while the guide wire is at the target tissue site; and removing the guide wire from the aspiration lumen of the aspiration catheter prior to aspirating the thrombus with the aspiration catheter.

49. The method of any of embodiments 44-47, further comprising: introducing a guide sheath having an inner sheath lumen within a vasculature of a patient; introducing a guide wire through the inner sheath lumen; wherein introducing the aspiration catheter within the vasculature of the patient comprises distally advancing aspiration catheter over the guide wire and through the inner sheath lumen until the distal aspiration port of aspiration catheter exits the inner sheath lumen; and wherein navigating the aspiration catheter within the vasculature of the patient to the target tissue site comprises navigating the aspiration catheter over the guide wire until the distal aspiration port of the aspiration catheter is adjacent target tissue site.

50. The method of any of embodiments 44-49, wherein fluid pressure oscillator is operated as the aspiration catheter is navigated within the vasculature of the patient to the target tissue site at a frequency in the range of 0.1 Hz-100Hz, and operated when aspirating the thrombus into the distal aspiration port and through the aspiration lumen at a frequency in the range 1 Hz-20Hz.

51. A method of performing a medical procedure at a target tissue site within the vasculature of a patient, comprising: navigating an elongate intravascular device having a device lumen within the vasculature of the patient to the target tissue site; initially oscillating a fluid pressure within the device lumen while the elongate intravascular device is navigated within the vasculature of the patient to the target tissue site, thereby mechanically vibrating the elongate intravascular device; and performing a medical procedure at the target tissue site.

52. The method of embodiment 51 , wherein initially oscillating a fluid pressure within the device lumen comprises modulating a baseline elevated pressure greater than a mean arterial pressure (MAP) of the patient.

53. The method of embodiment 51 or embodiment 52, wherein the fluid pressure in the device lumen is continually oscillated as the elongate intravascular device is navigated within the vasculature of the patient to the target tissue site, such that a buildup of static friction at a lengthwise portion of the elongate intravascular device through a bend in the vasculature is prevented that would otherwise hinder distal advancement of the lengthwise portion of the elongate intravascular device through the bend in the vasculature.

54. The method of embodiment 51 or embodiment 52, wherein navigation of the elongate intravascular device within a bend in the vasculature of the patient causes a buildup of static friction at a lengthwise portion of the elongate intravascular device, thereby hindering distal advancement of the lengthwise portion of the elongate intravascular device through the bend, and wherein the fluid pressure in the device lumen is oscillated as the lengthwise portion of the elongate intravascular device is disposed within the bend, thereby releasing the buildup of static friction and facilitating distal advancement of the lengthwise portion of the elongate intravascular device through the bend in the vasculature of the patient.

55. The method of any of embodiments 51-54, further comprising: introducing a guide wire into the device lumen; navigating the guide wire within the vasculature of the patient to the target tissue site, wherein the elongate intravascular device is navigated within the vasculature of the patient over the guide wire to the target tissue site while the guide wire is at the target tissue site.

56. The method of any of embodiments 51-54, wherein the elongate intravascular device is a guide sheath, and the device lumen is an inner sheath lumen, the method further comprising distally advancing a working catheter having an operative element through the inner sheath lumen when the guide sheath is at the target tissue site until the operative element exits the inner sheath lumen, wherein the medical procedure at the target tissue site is performed by the operative element of the working catheter.

57. The method of any of embodiments 51-54, wherein the elongate intravascular device is a working catheter having an operative element, and the medical procedure is performed at the target tissue site with the operative element.

58. The method of embodiment 57, wherein the patient has a thrombus at the target tissue site, the working catheter is an aspiration catheter, the device lumen is an aspiration lumen, the operative element is a distal aspiration port, and the medical procedure comprises aspirating the thrombus within the distal aspiration port and through the aspiration lumen.

59. The method of embodiment 58, wherein aspirating the thrombus within the distal aspiration port comprises subsequently oscillating a fluid pressure within the aspiration lumen.

60. The method of embodiment 59, wherein the fluid pressure within the aspiration lumen is initially oscillated at a frequency in the range of 0.1 Hz-100Hz, and subsequently oscillated at a frequency in the range of frequency in the range of 1 Hz- 20Hz.

61. The method of embodiment 60, wherein subsequently oscillating the fluid pressure within the aspiration lumen comprises modulating a baseline vacuum pressure less than a mean arterial pressure (MAP) of the patient.

62. The method of embodiment 61 , wherein initially oscillating the fluid pressure within the aspiration lumen comprises modulating a baseline elevated pressure greater than the MAP of the patient.

Claims

CLAIMS What is claimed is:

2. The navigation assistance device of claim 1 , wherein the RHV comprises: a guide tube having a tube lumen configured for allowing passage of the inner elongate intravascular device therethrough, wherein the tube lumen is sealed to prevent backflow of blood therethrough; and a connector rotatably affixed to a distal end of the guide tube, the connector configured for being coupled to a proximal end of outer elongate intravascular device, such that the tube lumen is in fluid communication with the device lumen.

3. The navigation assistance device of claim 2, further comprising a pressure manifold comprising: the pressure chamber; the guide tube, wherein the guide tube is disposed within the pressure chamber and has at least one tube opening fluidly coupling the pressure chamber to the tube lumen; and a distal pressure port configured for fluidly coupling the tube lumen to the device lumen when the connector is coupled to the proximal end of the outer elongate intravascular device; wherein the fluid pressure oscillator is configured for oscillating a fluid pressure in the pressure chamber, such that a fluid pressure within the tube lumen is oscillated via the at least one tube opening.

4. The navigation assistance device of claim 3, wherein the at least one tube opening comprises a plurality of tube openings formed through a wall of the guide tube.

5. The navigation assistance device of claim 2, wherein the RHV is external to the pressure chamber, the RHV further comprising a side arm affixed to the guide tube, the side arm having a side arm lumen in fluid communication with the tube lumen, wherein the pressure chamber is configured for being in fluid communication with the tube lumen via the side arm lumen.

6. The navigation assistance device of any of claims 1-5, wherein the pressure chamber is configured for having a variable volume of pressure oscillating fluid, and the fluid pressure oscillator is configured for oscillating the variable volume of fluid within the pressure chamber.

7. The navigation assistance device of claim 6, further comprising a vent inlet configured for fluidly coupling a pressurized fluid source having a baseline elevated pressure to the pressure chamber, and wherein the fluid pressure oscillator is configured for oscillating the fluid pressure in the pressure chamber by oscillating the fluid pressure around the baseline elevated pressure.

8. The navigation assistance device of claim 7, wherein the navigation assistance device further comprises a fluid refill control element configured for selectively fluidly coupling the pressurized fluid source to the pressure chamber.

9. The navigation assistance device of claim 8, wherein, when a fluid pressure within the pressure chamber drops below a threshold fluid pressure, the fluid refill control element is configured for conveying fluid from the pressurized fluid source into the pressure chamber.

10. The navigation assistance device of any of claims 1-9, wherein the fluid pressure oscillator is configured for oscillating the fluid pressure in the pressure chamber at a frequency in the range of 0.1 Hz-100Hz.

11. The navigation assistance device of claim 1 , wherein the fluid pressure oscillator is configured for oscillating the fluid pressure in the pressure chamber at a frequency in the range of 0.5Hz-50Hz.

12. An intravascular medical system, comprising; the navigation assistance device of any of claims 1-11 ; the outer elongate intravascular device; and the inner elongate intravascular device.

13. The intravascular medical system of claim 12, wherein the outer elongate intravascular device is a guide sheath, and the inner elongate intravascular device is a working catheter.

14. The intravascular medical system of claim 12, wherein the outer elongate intravascular device is a working catheter, and the inner elongate intravascular device is a guide wire.

15. The intravascular medical system of any of claims 12-14, wherein at least one of the outer elongate intravascular device and another elongate intravascular device configured for insertion into the inner lumen of the outer elongate intravascular device comprises a discontinuity that decreases a clearance between the other elongate intravascular device and the device lumen, such that a magnitude of the mechanical vibration is increased at the discontinuity.

16. The intravascular medical system of claim 15, wherein the other elongate intravascular device is the inner elongate intravascular device.

17. The intravascular medical system of claim 15, wherein the other elongate intravascular device is a dedicated obturator.

18. A navigation assistance/aspiration device for use with an aspiration catheter having an aspiration lumen and a distal aspiration port, comprising: a pressure manifold comprising: a pressure chamber; a distal pressure port configured for fluidly coupling the aspiration catheter to the pressure chamber; a vent inlet configured for fluidly coupling a pressurized fluid source to the pressure chamber, thereby allowing the pressurized fluid source to apply a baseline elevated pressure to the pressure chamber; a vacuum outlet configured for fluidly coupling a vacuum source to the pressure chamber, thereby allowing the vacuum source to apply a baseline vacuum pressure to the pressure chamber; a controller configured for selectively fluidly coupling the pressurized fluid source to the pressure chamber via the vent inlet or fluidly coupling the vacuum source to the pressure chamber via the vacuum outlet; a fluid pressure oscillator configured for oscillating a fluid pressure within the pressure chamber, such that the baseline elevated pressure within the pressure chamber is modulated when the controller fluidly couples the pressurized fluid source to the pressure chamber via the vent inlet, and the baseline vacuum pressure within the pressure chamber is modulated when the controller fluidly couples the vacuum source to the pressure chamber.

19. The navigation assistance/aspiration device of claim 18, wherein the baseline elevated pressure is above the mean arterial pressure (MAP) of a patient.

20. The navigation assistance/aspiration device of claim 19, wherein the vent inlet is further configured for fluidly coupling an atmospheric fluid source to the pressure chamber, and the controller is further configured for selectively fluidly coupling the atmospheric fluid source to the pressure chamber via the vent inlet concurrently with fluidly coupling the vacuum source to the pressure chamber via the vacuum outlet.

21 . The navigation assistance/aspiration device of claim 20, further comprising a fluid refill control element configured for conveying fluid from the pressurized fluid source into the pressure chamber when a fluid pressure within the pressure chamber drops below a threshold fluid pressure.

22. The navigation assistance/aspiration device of claim 20, further comprising means for selectively fluidly coupling the pressurized fluid source or the atmospheric pressure source to the vent inlet.

23. The navigation assistance/aspiration device of any of claim 18-22, further comprising a rotary hemostasis valve (RHV) fluidly coupling the pressure chamber to the aspiration lumen of the aspiration catheter.

24. The navigation assistance/aspiration device of claim 23, wherein the RHV comprises: a guide tube having a tube lumen configured for allowing passage of a guide wire therethrough, and wherein the tube lumen is sealed to prevent backflow of blood therethrough; and a connector rotatably affixed to a distal end of the guide tube, the connector configured for being coupled to a proximal end of the aspiration catheter, such that the tube lumen is in fluid communication with the aspiration lumen.

25. The navigation assistance/aspiration device of claim 24, wherein the pressure manifold further comprises the guide tube, wherein the guide tube is disposed within the pressure chamber and has at least one tube opening fluidly coupling the pressure chamber to the tube lumen, wherein the distal pressure port is configured for fluidly coupling the tube lumen to the device lumen when the connector is coupled to the proximal end of the aspiration catheter, wherein the fluid pressure oscillator is configured for oscillating a fluid pressure in the pressure chamber, such that a fluid pressure within the tube lumen is oscillated via the at least one tube opening.

26. The navigation assistance/aspiration device of claim 25, wherein the at least one tube opening comprises a plurality of tube openings formed through a wall of the guide tube.

27. The navigation assistance/aspiration device of claim 24, wherein the RHV is external to the pressure chamber, the RHV further comprising a side arm affixed to the guide tube, the side arm having a side arm lumen in fluid communication with the tube lumen, wherein the pressure chamber is configured for being in fluid communication with the tube lumen via the side arm lumen.

28. The navigation assistance/aspiration device of any of claims 18-27, wherein the pressure chamber is configured for having a variable volume of pressure oscillating fluid, and the fluid pressure oscillator is configured for oscillating the variable volume of fluid within the pressure chamber.

29. The navigation assistance/aspiration device of any of claim 18-28, wherein the controller is further configured for outputting a waveform signal corresponding to a modulated therapeutic pressure waveform, wherein the fluid pressure oscillator is configured for oscillating the variable volume of the pressure modulating fluid within the pressure chamber in accordance with the waveform signal, thereby modulating the baseline vacuum pressure.

30. The navigation assistance/aspiration device of any of claims 18-29, further comprising a sensor configured for measuring a parameter indicative of a fluid pressure at the distal end of the aspiration catheter, wherein the controller is configured for, in response to the measured parameter, dynamically modifying the waveform signal, and wherein the fluid pressure oscillator is configured for oscillating the variable volume of the pressure modulating fluid within the pressure chamber in accordance with the dynamically modified waveform signal, such that the fluid pressure at the distal end of the aspiration catheter tracks a desired modulated pressure waveform.

31 . The navigation assistance/aspiration device of any of claims 18-30, wherein the fluid pressure oscillator is configured for oscillating the fluid pressure in the pressure chamber at a frequency in the range of 0.1 Hz-100Hz when the pressurized fluid source is fluidly coupled to the pressure chamber, and for oscillating the fluid pressure in the pressure chamber at a frequency in the range of 1 Hz-20Hz when the vacuum source is fluidly coupled to the pressure chamber.

32. An intravascular medical system, comprising; the navigation assistance/aspiration device of claim 18; the aspiration catheter; and a guide wire for insertion into the aspiration lumen.

33. The intravascular medical system of claim 32, wherein at least one of the aspiration catheter and an elongate intravascular device is configured for insertion into the aspiration lumen comprises a discontinuity that decreases a clearance between the elongate intravascular device and the aspiration lumen, such that a magnitude of the mechanical vibration is increased at the discontinuity.

34. The intravascular medical system of claim 33, wherein the elongate intravascular device is the guide wire.

35. The intravascular medical system of claim 33, wherein the other elongate intravascular device is a dedicated obturator.