HK40070034B - System for removing a clot or embolus from a blood vessel - Google Patents

Description

Systems used to remove clots or emboli from blood vessels

Background of the Invention

1. Related Cases

This application claims priority to U.S. Provisional Application No. 62/249,249, filed October 31, 2015, and U.S. Provisional Patent Application No. 62/251,069, filed November 4, 2015, the entire contents of which are incorporated herein by reference.

2. Field of Invention

This invention relates primarily to equipment and methods for clot recovery, and removal devices for treating ischemic stroke, etc.

3. Existing Technology

Currently, FDA-approved treatment options for acute ischemic stroke include intravenous (IV) delivery of clot-dissolving drugs and mechanical thrombectomy.

For therapeutic purposes, clot-dissolving drugs such as thrombolytic agents (tissue plasminogen activator (t-PA)) are injected into the vascular system to dissolve clots that prevent blood flow to the neurovascular system. Intravenous t-PA is currently limited in use because it must be administered within a three-hour window following stroke onset and may increase the risk of bleeding. This standard of care leaves room for escalation and is only appropriate for a limited range of individual, group, and time-constrained emergencies.

The second option includes the use of mechanical thrombectomy devices. Such devices are designed to physically capture the embolism or clot and remove it from the blocked blood vessel, thereby restoring blood flow. A major advantage of mechanical thrombectomy devices is that they can extend the treatment window from three hours to more than ten hours.

Some existing mechanical thrombectomy devices for increasing blood flow through blocked blood vessels include: 1) filter traps designed and constructed for collecting and removing emboli; 2) cork screw-guidewire devices for retrieving emboli; and 3) stent-like devices connected to a delivery line for emboli retrieval. All of these devices have certain drawbacks.

First, filter-type thrombectomy devices are often bulky and difficult to deliver and deploy, and may require larger guiding catheters to completely remove the embolus. Additionally, coordinating precise and predictable movements to correctly position the device within the vessel is challenging. The device may drift, twist, or fail to adequately anastomose with the vessel wall, thus failing to effectively remove the embolus.

Cork screw guidewire devices can only capture and remove firmly attached plugs or plugs that are affected by certain mechanical variables, such as holding themselves together as a whole. Cork screw guidewire devices are not effective at removing particulate matter that may scatter or break apart.

Stent-type mechanical thrombectomy devices cannot capture small emboli that have broken off from large emboli (if any) and may lead to complications such as blockage of smaller distal vessels, vascular anatomy, perforation, and bleeding due to over-manipulation of vessels.

Common disadvantages of all the aforementioned devices include, for example: 1) the device may capture an embolus but subsequently lose control of it and inadvertently migrate/deposit it in another area of the neurovascular system, potentially creating new strokes in different parts of the neurovascular system; 2) the device cannot capture small emboli that have detached from a larger embolus and prevent them from moving to more distal areas of the neurovascular system; 3) the relatively large device profile prevents these devices from handling distal, smaller diameter vessels; and 4) the risk of symptomatic intracranial hemorrhage (sICH) after removal of intra-arterial clots in patients with acute stroke.

Other shortcomings in current mechanical thrombectomy designs include poor visibility/radiation opacity, a lack of enhancements and variations in delivery capacity in the delivery section, and a lack of coatings or modified surface textures to enhance embolic affinity in the treatment section. In summary, there is a strong need for improved devices, systems, and methods for restoring blood flow through blood vessels. Existing medical mechanical thrombectomy devices have not addressed all the necessary needs to date.

Summary of the Invention

This invention relates to a method and apparatus for removing clots, emboli, and other luminal obstructions from a blood vessel. A clot removal device is provided, comprising a deployable treatment component having a distal tip and a proximal end, a delivery line coupled to the distal end of the proximal end of the deployable treatment component, and a flow restrictor carried along the delivery line at a location separate from and adjacent to the deployable treatment component. The flow restrictor includes a body having a distal segment and a proximal segment, the distal segment being covered and the proximal segment uncovered. An access catheter is delivered to a location proximal to the location of the clot or embolism in the blood vessel, and then the clot removal device is delivered through the lumen of the access catheter to the location of the clot or embolism in the blood vessel. The deployable treatment component deploys at or distal to the location of the clot or embolism, and the clot or embolism is captured within or engaged with the deployable treatment component. The inlet catheter is then positioned relative to the flow restrictor so that the uncovered proximal segment is completely covered by the distal end of the inlet catheter, and the covered distal portion forms a seal with the distal end of the inlet catheter. Aspiration is then applied through the inlet catheter and through the uncovered proximal segment to remove clots or emboli from the blood vessel.

The clot removal device of the present invention can also be used according to another method, wherein the clot removal device is delivered to the location of a clot or embolism in a blood vessel, a deployable treatment component deploys at or distal to the location of the clot or embolism, the clot or embolism is captured in or engaged with the deployable treatment component, the deployable treatment component retracts into the distal segment of the flow restrictor, and the deployable treatment component and the flow restrictor are retracted from the blood vessel.

The device of this invention can be made of biocompatible metallic materials (e.g., Nitinol ^™ , stainless steel, Co-Cr based alloys, Ta, Ti, etc.) or polymer-based biocompatible materials (polymers with shape memory effect, PTFE, HDPE, LDPE, polyester, polyester fibers, etc.). For ischemic stroke treatment, the deployable treatment component must be flexible enough to pass smoothly through the tortuous vascular system of the brain without requiring modification of the vascular contour at the target location.

As is known to those skilled in the art, the outline of the deployable therapeutic component must be small enough to reach the target treatment site.

Attached Figure Description

Figure 1 is a side view of a fully expanded clot removal device according to a first embodiment of the present invention.

Figure 2 is a side view of the clot removal device shown in Figure 1 in the compression direction within the microcatheter.

Figure 3A is a side view of the clot removal device of Figures 1 and 2, showing the deployable treatment component being fully pushed outside the microcatheter.

Figure 3B is a side view of the clot removal device of Figures 1 and 2, showing the control arm and deployable treatment component slightly pushed outside the microcatheter.

Figure 4 is a side view of a fully deployed clot removal device according to a second embodiment of the present invention.

Figure 5 is a side view of the clot removal device of Figure 4, showing the collection of clots in a blood vessel.

Figure 6A is a side view of the clot removal device of Figure 4, showing the clots collected in the deployable treatment component.

Figure 6B is a side view of the clot removal device of Figure 4, showing the clots collected inside the deployable treatment component and the deployable treatment component inside the proximal flow restrictor.

Figure 7 is a side view of a fully unfolded clot removal device according to a third embodiment of the present invention, showing clots trapped on the surface of the unfoldable treatment component and between pores.

Figure 8 is a side view of the clot removal device of Figure 7, showing the deployable treatment component being pushed into the proximal flow restrictor.

Figure 9 is a side view of the clot removal device of Figure 7, showing the deployable treatment component within the proximal flow restrictor.

Figure 10 is a side view of a fully deployed clot removal device according to a fourth embodiment of the present invention.

Figure 11 is a side view of the removal device of Figure 10, showing the deployable treatment component being pushed into the proximal restrictor, with a clot bonded to its outer surface.

Figure 12 is a side view of the removal device of Figure 10, showing the deployable treatment component within the proximal flow restrictor.

Figure 13A is an enlarged side view of an exemplary near-side current limiter design.

Figure 13B is an enlarged side view of an exemplary proximal current limiter design with a push wire connected from the proximal end.

Figure 13C is an enlarged side view of an exemplary proximal flow restrictor design, which has a through-cavity from the proximal end on the delivery element.

Figure 14A is an exemplary application guide of the proximal flow restrictor of Figure 13B combined with an inlet catheter (e.g., a guiding catheter or other surgical stent) (not in the aspiration position).

Figure 14B is an exemplary application guide of the proximal flow restrictor of Figure 13B combined with an inlet catheter (e.g., a guide catheter or other surgical stent) at the aspiration position.

Figures 15A-15C show another embodiment of the clot removal device according to the invention, wherein the deployable treatment component is omitted.

Detailed Implementation

The following detailed description is the best mode for carrying out the present invention. This description should not be considered limiting, but merely to illustrate the general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims.

This invention relates to a device for removing embolisms and other luminal obstructions. The device includes a deployable treatment component, such as a mesh or cage, associated with a proximal flow restrictor. During treatment, the deployable treatment component is positioned within or distal to the embolus within the vessel and then transitions to an deployed state. In some embodiments, the normal state of the deployable treatment component is a deployed configuration, and the deployable treatment component is compressed and delivered to the treatment site in a compressed configuration via a delivery sheath or catheter. The deployable treatment component deploys from the delivery sheath, causing it to recover to its normally deployed profile through elastic energy stored in the device. The deployment of the deployable treatment component allows it to engage with the embolus or clot at the site of obstruction. Furthermore, the proximal flow restrictor can also deploy to a larger diameter state when deployed from the delivery sheath or catheter. The deployment of the proximal flow restrictor advantageously restricts or defines forward blood flow and creates a pressure gradient within the vessel between the distal and proximal locations of the flow restrictor. This pressure gradient helps prevent the clot from being flushed away from the treatment component, thereby facilitating the removal of the embolus from the vessel. Specifically, the pressure difference can act like a vacuum to aid in the removal of the embolus from the vessel. After deployment, the deployable therapeutic component and the embolism engaged with it are removed from the vessel. During clot removal, the deployable therapeutic component (engaged with the clot) can also be first pulled within the proximal restrictor (i.e., the clot retraction component with the engaged clot is housed within the proximal restrictor), then pulled back into the guiding catheter, and removed from the vessel. Furthermore, aspiration/vacuum aspiration can be applied through access to the catheter lumen and the proximal restrictor lumen to prevent clot breakage and downstream flow.

In addition, the proximal flow restrictor modulates forward blood flow and allows for controlled (gradual) recovery of blood flow, reducing the risk of sICH (symptomatic intracranial hemorrhage) after removal of intra-arterial clots in patients with acute stroke.

The device of the present invention is suitable for removing obstructions within body cavities, and is particularly suitable for removing thrombi, embolisms, or atherosclerosis in the vascular system, including thrombi, embolisms, or atherosclerosis in arteries and veins. It should be understood that the dimensions of the device can be modified to suit specific applications. For example, the device of the present invention for treating deep vein thrombosis may have a larger cross-section than the device of the present invention for treating cerebral ischemia.

Compared to existing mechanical thrombectomy devices, the unique device design of this invention has the advantage of providing a proximal flow-limiting feature to prevent forward blood flow when the device is deployed during use. This feature can help eliminate or reduce the risk of clot flushing or rupture during the procedure.

Another important advantage provided by this invention is that the central lumen of the proximal flow restrictor can be used or combined with the lumen of the inlet catheter to apply inspiratory/suction force to help completely remove blood clots from the vascular system.

Therefore, the device described in this invention overcomes the shortcomings of the prior art, allowing for smooth delivery to the vascular system, safe retrieval, and removal of the entire embolism with minimal effort. In use, the mechanical thrombectomy device described in this invention can be compressed to a small profile and loaded onto a delivery system, and delivered to the target location in the blood vessel via a medical procedure such as using a delivery catheter. When the mechanical thrombectomy device reaches the target implantation site and unfolds to its normal unfolding profile using the elastic energy stored in the device (self-deploying device), it can be released from the delivery system.

Regarding the relative position of the deployable therapeutic component to the embolism or blood clot, it can be positioned at the site of the embolism or distal to it. When dealing with long embolisms, the deployable therapeutic component can also be used to remove the embolism multiple times by moving from the proximal segment to the distal segment until the entire embolism is removed.

Turning now to the accompanying drawings, Figures 1-2 illustrate a device 100 according to the invention for removing emboli and other luminal obstructions. Device 100 may be made of one or more pieces of Nitinol ^™ hyperelastic material or Nitinol ^™ hyperelastic alloy tubing. It may also be made of other biocompatible materials with hyperelastic or shape memory properties. Device 100 may be manufactured using laser cutting, machining, chemical processing, electrochemical processing, EDM, braiding, and related techniques known to those skilled in the art.

The device 100 has a delivery line extending from the distal end of a delivery line 104, carrying a deployable treatment component 102 along the delivery line 104. The delivery line 104 has a flexible distal tip 106 extending away from the deployable treatment component 102 and having a marking coil embedded therein. A plurality of laser cutting control arms 108 connect a proximal segment of the deployable treatment component 102 along the delivery line 104 to a hub 110. Specifically, each control arm 108 has an opposite end connecting the proximal segment of the deployable treatment component 102 and the hub 110, with a proximal flow restrictor 112 carried by the delivery line 104 and proximal to the hub 110. For visibility, a marking strip or marking coil may be incorporated into the proximal flow restrictor 112 and the deployable treatment component 102. At least one end of the proximal flow restrictor 112 is freely movable along the delivery line 104.

The deployable therapeutic component 102 can be configured as a capture basket for clots or emboli, and in this embodiment, the deployable therapeutic component is shaped into a cone in its fully deployed configuration, having a apex 120 at its distal segment fixed to the delivery line 104, adjacent to the distal end 106. The diameter of the deployable therapeutic component 102 increases radially until it reaches its nearest side ring 122. The deployable therapeutic component 102 can be made of nitinol braided mesh and can be formed into a cone shape by a thermomechanical process. Crucially, the deployable therapeutic component 102 is not cylindrical in construction, which allows it to better conform to the vessel contour and move more freely within the vessel. The opening size of the ring 122 can range from 0.5 mm to 12 mm. The length from the apex 120 to the distal cone segment of the ring 122 can range from 2 mm to 40 mm.

The mesh frame of the deployable treatment component 102 may have multiple openings. Frame members or supports form the body of the mesh frame and define the multiple openings. In some embodiments, the frame members are multiple intersecting wires or other lines. The frame members may form a mesh or cage-like structure defining the multiple openings. In some embodiments, the deployable treatment component 102 may include multiple protrusions 150 on the frame. Referring to FIG1, the multiple protrusions 150 further engage emboli for removal.

As an alternative to or in addition to the plurality of protrusions 150, the deployable treatment component 102 may include one or more surface modifications or treatments. For example, as explained in more detail below, the surface of the deployable treatment component 102 may be roughened to improve clot adhesion.

The main geometric axis of the deployable treatment component 102 may be offset from or different from the longitudinal central axis of the native blood vessel. When the deployable treatment component 102 is in use, the axis of movement 102 of the delivery catheter (e.g., microcatheter 124) and/or the deployable treatment component may be different from the longitudinal central axis of the blood vessel and may contact the sidewall of the blood vessel.

The delivery line 104 can be made of super-elastic Nitinol ^™ wire, stainless steel wire, braided stainless steel wire, Co-Cr alloy, and other biocompatible materials. The diameter of the delivery line 104 can range from 0.008” to 0.030”, and the delivery line 104 can have variable diameter/stiffness along its length.

The distal end 106 may be made of a nontransparent Ta, Pt, W, Pt-W or Pt-Ir alloy and a nontransparent coil or marker.

The control arms 108 may be laser-cut from a superelastic Nitinol ^™ material. They are preferably taut when the deployable treatment component 102 is in its fully deployed configuration. The control arms 108 are used to control the opening diameter of the ring 122, such that the maximum diameter of the ring 122 is achieved when the control arms 108 are fully extended from the sheath of the microcatheter 124 (see Figure 2). The diameter of the ring 122 can be adjusted by the length of the control arms 108 extended from the microcatheter 124. Although this embodiment is described as having three control arms 108, one or more control arms 108 may be provided.

Hub 110 may be made of a non-transparent material and may move freely along and relative to delivery line 104. Hub 110 may also be fixed to a fixed position along delivery line 104.

The proximal flow restrictor 112 may be a spherical structure and may be made of Nitinol ^™ mesh, with its proximal end fixedly connected to the delivery line 104, while the distal end of the proximal flow restrictor 112 may be freely movable relative to the delivery line 104. In another embodiment, the proximal flow restrictor 112 may be fixedly connected to the delivery line 104 at its distal end, while the proximal end of the proximal flow restrictor 112 may be freely movable along and relative to the delivery line 104. The proximal flow restrictor 112 may have a first smaller compression profile for delivery through the microcatheter 124. When released from the microcatheter 124 or other delivery system, the proximal flow restrictor 112 may have a second larger unfolded diameter/profile to close, restrict, or define blood flow. The spherical structure may be a braided or laser-cut structure and may be made of a thin film, membrane, braided, or mesh material. In some embodiments, the proximal flow restrictor 112 is a polymer membrane or membrane. In other embodiments, the proximal flow restrictor 112 is a braided or woven mesh formed from metal, polymer, or a combination thereof. The type and material of the proximal flow restrictor 212 can be selected based on the desired coverage area (i.e., the flow rate to be restricted). The surface of the proximal flow restrictor can be completely or partially covered by some polymer material to restrict blood flow. It can be manufactured from one or two elements of device 100, or from other material sheets, and then attached to the delivery line 104 by mechanical means or by thermal (laser or welding) processes or adhesives/glue or heat-shrink technology. The spherical structure can also be manufactured from a single piece of Nitinol ^™ tubing identical to device 10 by laser cutting or chemical processes, and then shaped to a larger diameter than the original Nitinol tubing.

The diameter of the proximal flow restrictor 112 in its fully deployed configuration is approximately the same as the diameter of the opening ring 122 of the deployable treatment component 102 in its fully deployed configuration. The diameter of the proximal flow restrictor 112 can range from 0.5 mm to 12 mm, and its length can range from 2 mm to 60 mm.

Transparent markers can be attached to any part of device 100 for positioning. One way to provide full visibility of device 100 is to pass a transparent material through all or part of the lumen of delivery line 104. Markers can also be placed on deployable treatment component 102 to aid in positioning. Alternatively, transparent markers (marker coils, marker strips, transparent wires, transparent coatings, etc.) can be integrated into proximal flow restrictor 112.

Device 100 may have surface treatments on selected sections to improve the performance of those selected sections. Both the proximal restrictor 112 and the deployable treatment component 102 may be fully or partially coated or covered with typical biocompatible materials for lubrication purposes. The surface of the deployable treatment component 102 may have a positive or negative charge to improve clot adhesion. The surface of the deployable treatment component 102 may also be mechanically or chemically treated to have a “rough” surface to improve clot adhesion. A “rough” surface may be achieved by (i) a porous surface coating or layer, (ii) a microblasted surface or micro-jet, or (iii) an irregular strut geometry or arrangement.

The deployable therapeutic component 102 may be fully or partially coated with chemicals, drugs, or other biological agents to prevent clotting and/or to improve adhesion between the device and the embolus. Furthermore, the surfaces of the deployable therapeutic component 102 and the proximal restrictor 112 may be treated to form different surface layers (e.g., oxide layers, nitro or carbonized or N-C composite surface layers, etc.) to improve adhesion between the deployable therapeutic component 102 and the embolus.

Figure 2 illustrates the device 100 compressed and assembled within the microcatheter 124. In use, a guidewire can be inserted through the vascular system to the target treatment site, and then the microcatheter 124 is delivered across the guidewire to the target location in the blood vessel using conventional delivery techniques known to those skilled in the art, with the device 100 housed therein. Alternatively, the microcatheter 124 can be first inserted onto the guidewire, and then the compressed device 100 can be inserted through the lumen of the microcatheter 124. The distal end of the microcatheter 124 can be positioned proximal, internal, or distal to the clot or embolism at the target location, and the microcatheter 124 does not need to pass through the clot or embolism, thereby minimizing the possibility of pushing the clot or embolism downstream of the blood vessel.

The microcatheter 124 can then be pulled back (proximal) to first expose the deployable treatment component 102 (see Figure 3A), then the control arm 108, and then the proximal flow restrictor 112. The deployable treatment component 102 will not reach its full diameter until the control arm 108 is fully exposed, allowing the deployable treatment component 102 to not interfere with the clot before the device 100 reaches its desired position. Alternatively, the deployable treatment component 102 can be deployed by inserting the device 100 into the microcatheter 124 until the distal tip 106 reaches the distal end of the microcatheter 124, then holding the proximal end of the microcatheter 124 stationary, and pushing the device 100 distally out of the microcatheter 124. In this alternative, retraction of the microcatheter 124 is not required, allowing for more precise positioning. The deployable treatment component 102 will not fully deploy (i.e., reach its maximum diameter) until the control arm 108 is fully extended out of the microcatheter 124. This allows for a gap, volume, or space (see Figure 3B) between the deployable treatment component 102 and the actual clot in the blood vessel, such that when the deployable treatment component 102 is extended from the microcatheter 124 and positioned distal to the clot, the clot is not pushed downstream and removed by the deployable treatment component 102. Once the control arm 108 has been fully extended from the microcatheter 124, the deployable treatment component 102 will reach its full diameter to capture the clot distal to the clot. At this point, the microcatheter 124 and the extended delivery line 102 will be simultaneously pulled back or removed to remove the clot.

During this procedure, the proximal flow restrictor 112 eliminates or reduces forward blood flow to minimize the risk of clot retention and displacement. The deployable treatment component 102 collects all clots/emboli to prevent them from flowing downstream. The proximal flow restrictor 112 also modulates blood flow during and immediately after the procedure to eliminate the effects of sICH for better clinical outcomes.

In other embodiments, the proximal flow restrictor may surround (i) the outer surface or diameter of the proximal segment of the deployable treatment member, or (ii) both or the diameter of the inner and outer surfaces of the proximal segment of the deployable treatment member. In these embodiments, the proximal flow restrictor may cover a length extending from (i) the proximal end of the deployable treatment member to approximately half the length of the deployable treatment member, or (ii) a length extending from the proximal end of the deployable treatment member to approximately one-quarter of the length of the deployable treatment member.

For example, Figures 4-6 illustrate another embodiment of the device 200 for removing embolisms and other endoluminal obstructions. Aside from some differences, the device 200 also has a deployable treatment component 202, a soft distal tip 206 (with a marking coil), a delivery line 204, a control arm 108, a hub 110, and a proximal flow restrictor 212, respectively corresponding to the first embodiment.

First, the deployable treatment component 202 has a slightly different construction. Instead of the conical construction of the deployable treatment component 102, the deployable treatment component 202 has a truncated conical body 228, whose distal end does not terminate at the apex, but has a small distal opening.

Second, the proximal current limiter 212 has a different construction, having a body comprising a cylindrical distal section 230 and a generally conical (or truncated conical) proximal section 232 with a gradually tapering construction. The two sections 230 and 232 are combined to define a receiving section.

The body 228 and segments 230 and 232 may all be laser-cut from the same material (e.g., Nitinol ^™ tubing or sheet), but the dimensions of the holes or openings 234 in the body 228 and segments 230 and 232 may vary to alter the flexibility of the different bodies 228 or segments 230, 232. Segment 232 may have an annular distal edge 240 serving as an opening. Segments 230 and 232 may also have different sizes/porosities and may be covered or uncovered by a biocompatible polymer. One example is covering segment 230 while leaving segment 232 uncovered. The uncovered segment 232 may be combined with other inlet catheters to facilitate aspiration/suction functionality. The proximal restrictor 112 may have a braided configuration.

Third, the delivery line 204 may have a deflection segment 238 that extends at an angle relative to the central longitudinal axis away from segment 230 to a hub 210 offset from the central longitudinal axis occupied by the delivery line 204. At this point, the control arm 208 extends from the hub 210 toward the body 228 at different angles. These different angles allow the deployable treatment component 202 to pass more easily through vascular anatomy and also better facilitate the collection of clots and particles by the deployable treatment component 202. Additionally, the different angles of the control arm 208 allow the proximal opening of the deployable treatment component 202 to remain open and not collapse during the procedure. The different angles also make it easier for the control arm 208 to control the diameter or staged deployment of the deployable treatment component 202 during the procedure.

The proximal flow restrictor 212 is configured to undergo relative movement with respect to the deployable treatment component 202. This is achieved by not having a fixed connection between the proximal flow restrictor 212 and the delivery line 204 and by allowing the proximal flow restrictor 212 to slide along the delivery line 204. In other words, the deployable treatment component 202 can move independently of the proximal flow restrictor 212. This provides more efficient clot capture and removal, as described below.

In use, device 200 is loaded within microcatheter 124, and the microcatheter 124 and the device 200 contained therein are delivered to a target location in the blood vessel using conventional delivery techniques known to those skilled in the art. The distal end of microcatheter 124 can be repositioned proximal to or within a clot or embolism at the target location, and microcatheter 124 does not need to penetrate the clot or embolism. Device 200 can then be pushed distally to the distal end of microcatheter 124 to first expose deployable therapeutic component 202, and then proximal flow restrictor 212. See Figure 5. Device 200 is then pulled back or retracted such that deployable therapeutic component 202 captures the clot. See Figure 6A. When the delivery line 204 is pulled back and the deployable therapeutic component 202 is pulled back accordingly, the proximal restrictor 212 can remain in the same position within the blood vessel, such that when the annular distal edge 240 of the proximal restrictor 212 contacts the annular proximal edge or ring 222 of the body 228, and further proximal pulling of the delivery line 204 causes the deployable therapeutic component 202 to be pulled back into the cylindrical segment 230, thus removing the entire device 200 from the blood vessel. As a result, during removal, the entire clot or embolism can be retained within the cage defined by the deployable therapeutic component 202 and the proximal restrictor 212 to prevent clot displacement or detachment. See Figure 6B. The deployment diameter of the annular proximal edge 222 is preferably slightly smaller than the deployment diameter of the cylindrical segment 230 and its annular proximal edge 240, so that the deployable therapeutic component 202 can be retained within the cylindrical segment 230.

Alternatively, the delivery line 204 may be provided with a cavity that opens at an opening located within the proximal restrictor 212 (see Figures 13-14 below), allowing smaller clots and particles to be drawn into the proximal restrictor 212 from the proximal end 124 of the guide catheter or microcatheter using suction, and then removed from the container.

Finally, the suction/inhalation action entering the inner cavity of the device and the encapsulation (clot bonding) of the deployable treatment component 102 can occur simultaneously or sequentially during the procedure.

Figures 7-9 illustrate another embodiment of the device 300 for removing embolisms and other luminal obstructions. Aside from some differences, device 300 is similar to device 200 in that it also has deployable treatment components 302, delivery line 304, hub 310, and proximal flow restrictor 212, respectively, corresponding to the delivery line 204, hub 210, and proximal flow restrictor 212 of the second embodiment.

First, the deployable therapeutic component 302 has a different construction and can be constructed as any removal device disclosed in co-pending U.S. Application No. 2015-0150672, filed January 16, 2015, the entire disclosure of which is incorporated herein by reference as if fully set forth herein. For this reason, there is no control line 108/208.

Secondly, the proximal current limiter 312 can be substantially the same as the proximal current limiter 212 in Figures 4-6.

Third, the hub 310 can be used as a marker or plug. During the procedure, as the deployable treatment component 302 is pulled back, once the hub 310 reaches and engages the proximal end of the proximal flow restrictor 312, the deployable treatment component 302 will begin to pull the proximal flow restrictor 312. At this stage, the entire (or part) deployable treatment component 302 and its collected clots have been held within the proximal flow restrictor 312. Again, suction force can be applied from the proximal end of the guide catheter or microcatheter to help pull all clots/emboli within the proximal flow restrictor 312.

Furthermore, both the main body of the deployable treatment component 302 and portions of the proximal flow restrictor 312 can be laser-cut from the same material (e.g., Nitinol ^™ tubing or sheet), but the dimensions of the units or openings in the deployable material for the treatment component 302 and the proximal flow restrictor 312 can be varied to achieve altered flexibility. The proximal conical portion of the proximal flow restrictor 312 can be left uncovered, while the straight section of the proximal flow restrictor 312 can be covered to achieve the desired aspiration effect and aspiration control.

As shown in Figure 7, the clot can be captured on the surface of the deployable treatment component 302 and between the pores, and the entire system (microcatheter and device 300) is removed from the blood vessel after the deployable treatment component 302 is fully pulled into the proximal restrictor 312 (see Figures 8-9). Because the proximal restrictor 312 does not have a fixed connector with the delivery line 304, it can be held in a fixed position relative to the delivery line 304 and the deployable treatment component 302, allowing the deployable treatment component 302 (with the clot attached) to be pulled into the proximal restrictor 312. The deployable treatment component 302 can be pulled into the proximal restrictor 312 until the hub 310 (acting as a stop) contacts the narrowed portion of the proximal segment 332 of the proximal restrictor 312. The proximal segment of the deployable treatment component 302 has a tapered construction, allowing it to fit into the narrowed proximal segment 332. At this point, when the delivery line 304 is pulled out, the proximal flow restrictor 312 will move together with the deployable treatment component 302 (and the blood clot contained therein). The device 300 can be pulled out of the vessel within the guiding catheter, or it can be removed from the vessel without first being pulled into the guiding catheter. Similarly, a suction force can be applied proximally from the entry into the guiding catheter or microcatheter to help remove any clots/emboli within the proximal flow restrictor 312.

Figures 10-12 illustrate another embodiment of the device 400 for removing embolisms and other endoluminal obstructions. Aside from some differences, device 400 is similar to device 100 in that it also has deployable treatment component 402, delivery line 404, distal end 406, and proximal flow restrictor 412, respectively, corresponding to the deployable treatment component 102, delivery line 404, distal end 106, and proximal flow restrictor 412 in the first embodiment.

First, the deployable therapeutic component 402 has a different construction and a distal segment 440 that is substantially the same as the cone-shaped deployable therapeutic component 102. However, the deployable therapeutic component 402 also has a proximal segment 442, which is also conical and has a apex 444 at its proximal end, and its maximum diameter portion is connected to the maximum diameter portion of the distal segment 440. The biconical construction of the deployable therapeutic component 402 allows for a softer distal end and less trauma, and also provides a less rigid proximal end, which facilitates passage within vascular anatomy. The distal deployable therapeutic component 402 can be completely or partially covered by a polymer material to occlude blood flow (flow from the distal portion of the vessel to the proximal segment of the vessel), making the inspiratory effect from the inlet catheter and proximal flow restrictor more effective.

Secondly, the proximal current limiter 412 can be substantially the same as the proximal current limiter 212 in Figures 4 and 6.

Third, there is no hub 110 and no control line 108/208.

Furthermore, the body of the deployable treatment component 402 and the section of the proximal flow limiter 412 can both be laser-cut from the same material (e.g., Nitinol ^™ tubes or sheets), but the size of the holes or openings in the deployable treatment component 402 and the proximal flow limiter 412 can be varied to achieve different levels of flexibility.

The clot can be engaged laterally to the distal segment 442 (see Figure 11), and the deployable therapeutic component 402 can be fully pulled into the proximal restrictor 412 (see Figures 11 and 12) before the entire system (microcatheter and device 300) is removed from the vessel. Because the proximal restrictor 412 does not have a fixed connector to the delivery line 404, it can be held in a fixed position relative to the delivery line 404 and the deployable therapeutic component 402, allowing the deployable therapeutic component 402 (with the clot engaged on its outer surface) to be pulled into the proximal restrictor 412. Aspiration can be applied during the procedure by entering the lumen of the catheter or microcatheter and the proximal restrictor.

Figures 13A, 13B, and 13C illustrate some exemplary design configurations of braided proximal current limiters. The proximal current limiters shown in Figures 13A-13C and 14A-14B can be the same as proximal current limiter 212, but the principles and concepts embodied in Figures 13A-13C and 14A-14B are also applicable to other proximal current limiters shown and described herein.

As shown in Figure 13B, the proximal restrictor 212 may have a central lumen 260 located at the proximal end 262, a tapered proximal section 232, and a cylindrical distal section 230. The proximal section 232 may be uncovered, and the distal section 230 may be covered with a biocompatible polymer material. In use, suction can be applied through the central lumen 260 from the inlet catheter.

As shown in Figure 13B, push wire 264 can be connected to proximal section 232 to operate proximal flow restrictor 212. This design can be used with or combined with other commercially available clot removal devices, and can also be used or combined with inlet catheters, guide catheters, DACs, or microcatheters to apply suction during clot removal.

As shown in Figure 13C, different central lumen structures 260a with lumens can be connected to the proximal segment 232 to operate the proximal restrictor 212. This design can be used or combined with other commercially available clot removal devices, and can also be used or combined with inlet catheters, guide catheters, DACs, or microcatheters to apply suction during clot removal.

Figures 14A and 14B illustrate exemplary applications of the proximal flow restrictor feature. The proximal segment 232 may be completely uncovered or partially uncovered, and the distal segment 230 may be covered with a biocompatible polymer material. In use, the proximal flow restrictor 212 can be delivered to a target location via a microcatheter or other access catheter 224. The proximal central lumen 260 can be used to slide along the guidewire or push wire 264 of the clot retrieval device. By adjusting the relative position/location of the microcatheter 224 and the proximal flow restrictor 212, the proximal flow restrictor 212 can allow proximal forward flow or cut off forward flow. In the case of cut-off forward flow, suction can be applied through the lumen of the microcatheter 224 to improve clot collection, preservation, and removal. For example, when the push wire 264 connected to the proximal restrictor 212 is pulled back into the inlet catheter or microcatheter 224, and the uncovered proximal segment 232 is completely covered by the distal end of the inlet catheter or microcatheter 224, the covered distal segment 230 forms a seal with the distal end of the inlet catheter or microcatheter 224, completely cutting off forward flow. Suction/vacuum can then be applied from the proximal side of the inlet catheter or microcatheter 224 to help retain and collect clots (as shown in Figure 14B). It can be noted from Figure 14B that the outer diameter of the inlet catheter 224 is smaller than the outer diameter of the fully extended distal segment 230. However, this seal can still be formed when the proximal side of the distal segment 230 is pulled into the distal opening of the inlet catheter 224 because the proximal segment of the distal segment 230 begins to compress and exhibits a tapered structure when pulled into the inlet catheter 224.

Figures 15A-15C illustrate different embodiments of the invention, wherein the device 200 includes only the flow restrictor 212 and the pusher wire 264, and the deployable treatment component 202 is omitted. As shown in Figure 15A, the distal segment 230 is positioned proximal to the clot or embolism, and the relative position/location of the inlet catheter 224 is adjusted by manipulating the pusher wire 264 such that the proximal segment 232 of the flow restrictor is covered by the distal end of the inlet catheter 224. Aspiration is then applied to the lumen of the inlet catheter 224 to aspirate or aspirate the clot into the distal segment 230 and/or the proximal segment 232 (see Figure 15B), and then the entire flow restrictor 212 (including the clot inside) is pulled into the inlet catheter 224 (see Figure 15C), and the device 200 is removed from the blood vessel.

Alternatively, if the embodiment shown in FIG1 is used, as shown in FIG13C, suction can be applied through the central lumen 260a instead of through the inlet catheter 224.

Therefore, the embodiments of Figures 13C and 15A-15C show that the deployable treatment component 202 can be omitted, and the flow restrictor 212 can be used alone to remove blood clots or thrombi. The structural arrangement of the flow restrictor 212 (the uncovered proximal segment 232 and the covered distal segment 230) facilitates this type of removal.

The above description relates to specific embodiments of the invention, but it should be understood that many modifications can be made without departing from the spirit of the invention. The appended claims are intended to cover these modifications that fall within the true scope and spirit of the invention.

Claims (3)

1. A system for removing clots or emboli from a blood vessel, comprising: Delivery line; A flow restrictor, carried along the delivery line, having a body having a distal segment and a proximal segment, the body defining an outer surface extending from the proximal segment to the distal segment and a distal opening in the distal segment, the flow restrictor having an unfolded configuration and a folded configuration, the outer surface of the distal segment being circumferentially covered by a biocompatible polymer coating such that the distal opening is uncovered, and the outer surface of the proximal segment being uncovered in both the unfolded and folded configurations; and An access catheter with a distal end is configured to the location of a clot or embolism in a blood vessel and positioned relative to the flow restrictor in an unfolded configuration such that the uncovered proximal segment is completely covered by the distal end of the access catheter, and the covered distal segment forms a seal with the distal end of the access catheter, allowing suction to be applied through the lumen of the access catheter to aspirate the clot out or into the distal segment and/or the proximal segment. 2. The system according to claim 1, wherein the diameter of the uncovered proximal segment is smaller than the diameter of the covered distal segment. 3. The system according to claim 1, wherein the uncovered proximal segment is conical and the covered distal segment is cylindrical.