JP2014519395A - Radiofrequency ablation catheter device - Google Patents

Abstract

  A radio frequency ablation catheter device has a balloon catheter that can be expanded by inflation in several portions along its length. The catheter may have one or more different stretchable areas along its length, or generally has a non-stretchable body and one or more individual stretchable parts over it. Sometimes, these stretchable areas / portions can be individually inflated. One section of the catheter is stretched into a disc-like configuration with a circular, somewhat flat surface that is oriented perpendicular to the guide wire direction and faces in the distal direction. The catheter supports one or more RF electrodes, which can conduct RF energy and can be positioned on the surface of the balloon catheter to assume a circular configuration on a flat surface. it can. An unstretched balloon catheter is longitudinally advanced through the blood vessel to the appropriate location within the body cavity, inflated, and pushed distally. The electrode is brought into contact with the inner surface of the lumen so as to cauterize the nerve activity in a circumferential direction at a desired position such as around the renal artery opening of the aorta, and the nerve activity specifically communicated with the kidney is cauterized.

Description

  The present invention relates generally to medical devices and methods for treating vascular tissue by application of radio frequency energy, and more particularly to specific lesion sites through catheters and / or stents for nerve ablation or atherosclerosis ablation. The present invention relates to an ablation device for treating patient tissue by delivering therapeutic radio frequency energy.

  Arteries are tubular blood vessels that carry blood from the heart to body tissues and organs, each consisting of an outer fiber layer, a smooth muscle layer, connective tissue, and inner wall cells (vascular endothelium). Some arteries have complex structures that perform multiple functions. For example, the aorta, a complex structure that performs multiple functions, contains a neural network that helps maintain vascular tone, sodium and water excretion or reabsorption throughout the body and each individual organ, and blood pressure control. Electrical activity to these nerves originates from within the brain and peripheral nervous system.

  The kidney has a high density of afferent sensory nerve distribution and efferent sympathetic nerve distribution, thereby being centrally located to be the origin and target of sympathetic nerve activation. Communication with monolithic structures within the central nervous system occurs through afferent renal sensory nerves. The afferent nerve of the kidney projects directly into several areas within the central nervous system and indirectly projects into the anterior and posterior hypothalamus, contributing to arterial pressure regulation. Afferent renal sensory nerve activity regulates posterior hypothalamic activity to sympathetic nerves to the kidney and other organs with many nerves that are involved in cardiovascular control, such as the heart and peripheral blood vessels Affects output. These afferent and efferent nerves reach their target end organ sites via the aorta.

  Several studies suggest that conditions such as renal ischemia, hypoxia, and oxidative stress result in increased renal afferent activity. During ischemia, renal afferent nerve stimuli, which can be caused by metabolites such as adenosine, are generated, and uremic toxins such as urea, or electrical pulses, increase the reflex of sympathetic activity and blood pressure.

  Increased renal sympathetic nerve activity increases renin secretion rate, decreases urinary sodium excretion by increasing sodium reabsorption in renal tubules, and decreases renal blood flow and renal glomerular filtration rate. When nerve activity to the kidneys is increased, sodium and water are reabsorbed, afferent and efferent arterioles are narrowed, kidney function is reduced, and blood pressure is increased.

  Renin release may be hindered by sympathetic blockers such as clonidine, moxonidine, and beta blockers. Angiotensin receptor blockers significantly improve blood pressure control and cardiovascular effects. However, these treatments are limited in effect and have deleterious effects. In addition, many hypertensive patients exhibit treatment-resistant hypertension, with uncontrollable blood pressure and end organ damage due to hypertension.

  Patients suffering from renal failure and undergoing hemodialysis therapy show sustained activation of the sympathetic nervous system, which contributes to hypertension and increased cardiovascular morbidity and mortality. Signals generated in failing kidneys are thought to affect sympathetic activation during chronic kidney failure. Toxins that circulate in the blood due to renal failure can cause excitation of afferent nerves in the kidney, resulting in sustained activation of the sympathetic nervous system.

  Removal of afferent renal sensory nerves and efferent renal nerves has been demonstrated to reduce blood pressure and organ-specific damage caused by chronic sympathetic hypertony in various experimental models. Thus, functional denervation of the human kidney by targeting both efferent sympathetic and afferent sensory nerves is characterized by hypertension, and increased overall neural activity and especially renal sympathetic nerves It appears to be a useful treatment strategy for other clinical symptoms. Functional denervation in humans can also reduce the possibility of end organ damage associated with hypertension.

  In the treatment of many diseases and conditions, in situ destruction or size reduction of cells is used alone or as an adjunct to surgical removal procedures. This procedure is often less traumatic than a surgical procedure and may be the only option when other procedures are not safe or effective. This method, known as cauterization, applies appropriate heat to the tissue and causes the tissue to contract and tighten. Ablation devices have the advantage of using disruptive energy that is rapidly dissipated and reduced to a non-destructive level by the conduction and convection forces of the circulating fluid and by other natural body processes.

  In many medical procedures, it is important to be able to concentrate under control and cauterize unwanted tissue without affecting the surrounding desired tissue. As an alternative to resection surgery, a number of minimally invasive methods have been developed over the years to selectively destroy specific areas of unwanted tissue. There are a variety of techniques with particular advantages and disadvantages, which have been shown and contraindicated for various applications.

  In one technique, high temperature (heat) is used to cauterize the tissue. When the temperature exceeds 60 ° C., cellular proteins rapidly denature and coagulate, resulting in lesions. This lesion is used to excise and remove tissue, or simply disrupt the tissue, leaving a cauterized tissue. Thermal ablation can also be performed at multiple locations to provide a series of ablation, thereby causing the target tissue to die and become necrotic. Upon receiving heat, necrotic tissue is absorbed or excreted by the body.

  An electric current can be used to generate heat for tissue ablation. Radiofrequency (RF) ablation is a high temperature, minimally invasive technique where active electrodes are introduced into unwanted tissue and high frequency alternating currents up to 500 kHz are used to heat and coagulate the tissue. Is done. Radio frequency (RF) ablation devices work by transmitting alternating current through tissue, producing elevated intracellular temperatures and localized interstitial heat.

  RF therapy minimizes patient side effects and risks and is generally performed after first locating a tissue site for treatment. When combined with a temperature control mechanism, RF energy can be accurately delivered to the device-tissue contact site to obtain the desired temperature for treating the tissue. The tissue is cauterized by heating the tissue with an RF output emanating from a controlled radio frequency (RF) device and applied through the electrode tip.

  The theory and practice behind RF thermal damage has been known for decades, and there are a variety of RF generators and electrodes to achieve such practice. RF therapy protocols are used by electrophysical therapists for the treatment of tachycardia, when used by neurosurgeons for the treatment of Parkinson's disease, when gussel ganglion resection or refractory pain for trigeminal neuralgia. It has been demonstrated to be very effective when used by neurosurgeons and anesthesiologists for other RF procedures such as percutaneous cervical cordomas.

  Renal denervation can be achieved through the opening of the aortic renal artery ostium, ie, the branch of the aorta open to the renal artery. Ablation of neural activity at the renal artery ostium does not affect the blood flow from the aorta into the renal artery and causes the desired effect of renal denervation. However, one challenge in the art is to provide a treatment surface that can reach all desired treatment areas, such as the area surrounding the renal artery orifice in the circumferential direction. Although it may be known to use a catheter to deliver energy, it provides ablation around the entire opening of the aortic branch vessel opening, such as the renal artery ostium, to achieve optimal uniform treatment It ’s difficult.

  There is an urgent need in the art to develop techniques for effectively cauterizing nerve function within the kidney by disrupting nerve activity leading to the kidney. This mechanism can be achieved by ablation of neural activity at the level of the aorta, especially at the level of the renal artery ostium. Such an approach offers the advantage of improving blood volume in the body and lowering blood pressure.

  It would be desirable to provide an apparatus and system for cauterizing nerve function within the kidney by attacking the renal nerve via the renal artery ostium of the aorta.

  In general, it is an object of the present invention to provide a method for generating heat and an improved medical ablation device to effectively cauterize nerve function directed to the kidney of a subject or patient.

  Another object of the present invention is to deliver electrical energy, such as RF (radio frequency) energy, to the inner layer of the aortic wall for ablation of aortic nerve activity.

  A further object of the present invention is to deliver electrical energy, such as RF (radio frequency) energy, to the inner layer of the aortic wall, specifically to the renal artery ostium of the aorta, particularly for ablation of the aortic nerve leading to the kidney. .

  A further object of the present invention is to measure neural activity at the level of the aorta and within the renal arteries to confirm the success of the ablation procedure.

  The present invention is directed to devices, systems, and methods for delivering radio frequency energy using a non-conductive catheter to body cavities, particularly the inner lining of the aorta, specifically surrounding the renal artery ostium of the aorta. .

  In one example, the device comprises a cylindrical balloon catheter, for example, which can be stretched by inflation in several portions along its length. In one embodiment, the balloon catheter is a non-stretchable catheter that does not generally stretch, but has one or more individual stretchable sections over the non-stretchable catheter, the stretchable sections being , Individually or individually stretchable. In another embodiment, the balloon catheter is a non-stretchable catheter that generally does not stretch but has one or more different stretchable areas along its length, each section having a different level of stretch. In particular, inflation allows certain portions of the balloon catheter to expand more than other portions of the balloon catheter. In a further embodiment, the balloon catheter is a non-stretchable catheter that does not generally stretch but has one or more different stretchable areas along its length, each section having a different level of stretchability. And allowing the balloon catheter to expand a particular portion of the balloon catheter more than the other portions of the balloon catheter, the balloon catheter further comprising one or more individual pieces over the catheter. It also has stretchable portions, which cover stretchable portions may be individually or individually stretchable by expansion.

  The device is movable between a non-deployed position and a deployed position. In the undeployed position, the balloon catheter is non-stretched. The balloon catheter is in its undeployed position, for example over a guide wire, through a tubular guide catheter to an appropriate location within the body cavity, such as within the aorta, and further to a desired location within the inner circumference of the blood vessel, e.g. It can be advanced longitudinally through the blood vessel to the renal artery ostium of the aorta.

  In one example, the device supports one or more electrodes, which are capable of conducting RF energy and in contact with body tissue. In one example, the one or more electrodes are positioned in a circular configuration on a portion of the balloon catheter when the device is in its deployed position. If multiple electrodes are used, the circularly configured electrodes can be positioned so that the electrodes have a generally circular configuration or are concentrically oriented when the device is in the deployed position. The electrode is brought into contact with the inner surface of a lumen, such as the aorta, at the renal artery ostium, for example, so that the electrode cauterizes neural activity circumferentially around the renal artery ostium.

  When the device is in its deployed position, the stretchable segment of the balloon catheter (referred to as the balloon segment) is stretched to have a disc-like configuration with a circular, somewhat flat surface, Directed perpendicular to the direction of the wire and facing in the distal direction. One or more electrodes having a circular configuration are positioned on the balloon segment of the device, i.e., on the distal facing surface of the stretched balloon segment when the device is in its deployed position. This distally facing surface of the balloon segment can be pushed up against the renal artery ostium of the aorta, thereby allowing an electrode positioned in a circular configuration to contact the renal artery ostium of the aorta.

  Then, by supplying an appropriate RF energy source to the device, heat is generated at the electrodes and ablation is performed for ablation of neural activity, such as neural activity specifically leading to the kidney, at the renal artery ostium. Positioning the circular configuration of the RF element so that it is positioned circumferentially around the opening to the renal artery ensures improved delivery of RF energy to the designated location at the level of the aortic wall. . By including multiple RF elements within a single catheter system, a more complete nerve ablation may be obtained.

  This mechanism is also provided in a device design to position and secure the device in a desired location within a blood vessel, such as the aorta, so that the electrode can be moved in a precise position, i.e. around the renal artery ostium Sometimes.

  In one example, the positioning mechanism comprises a guide wire and a non-stretched area of the balloon catheter, where the non-stretched area is inserted at least partially at the entrance to the renal artery and remains there. If there is a guiding catheter over the expandable catheter, the guiding catheter is withdrawn proximally and then the balloon catheter segment is inflated. The sheath or guide catheter is then advanced distally and the distal edge of the sheath or guide catheter strikes the proximally facing surface of the expanded balloon segment, thereby expanding the expanded catheter segment. The RF electrodes on the distally facing surface can be positioned to contact the renal artery ostium, allowing the RF electrodes to perform their ablation function.

  In another embodiment, the positioning mechanism is an individually inflatable portion that is located distal to a separately expandable portion of the balloon catheter, ie, a balloon segment (referred to as a positioning segment) that protrudes into the entrance to the renal artery. With possible parts. This positioning segment of the balloon catheter is inserted at least partially into the entrance of the renal artery and then inflated only to the diameter of the renal artery, not the size of the balloon segment, so that the balloon catheter is It is prevented from moving distally or proximally relative to the artery, allowing the device to keep its position within the renal artery relative to the aorta. When the device is so positioned by the inflatable balloon at the positioning segment of the balloon catheter, the circular RF electrodes can be positioned to contact the renal artery ostium, so that the RF electrodes perform their ablation function. Can be implemented. In one embodiment, before the positioning segment of the balloon catheter is stretched, the distal edge of the sheath or guide catheter strikes the proximally facing surface of the stretched balloon segment, thereby stretching. The RF electrode on the distal facing surface of the balloon segment is positioned against the renal artery ostium.

  In yet another embodiment, the positioning mechanism comprises an imaging catheter at the distal end of the balloon catheter that allows the user to properly center and position the balloon catheter within the renal artery. Will be able to. The imaging catheter allows the user to see exactly where the renal artery ostium is located.

  For example, after the device is properly positioned by one of the positioning means described above, the balloon segment of the balloon catheter is expanded. When the stretched balloon segment of the balloon catheter is properly positioned, the distal facing surface of the stretched balloon segment of the balloon catheter abuts the inner edge of the aorta and Allow the RF electrode to be positioned relative to the surrounding aortic wall.

  The design also includes means for measuring renal nerve afferent and efferent activity before and after RF nerve ablation. Measuring renal nerve activity after treatment provides a certainty that proper nerve ablation has been achieved. Renal nerve activity is measured not only at the level of the renal artery ostium but also along the renal artery positioning balloon by the same electrode mechanism that is required for energy delivery.

  In addition to the functions described above, the device comprises a mechanism for cooling the aortic wall to limit the potential for damage to the aortic endothelium surface, while ablation energy is effectively transmitted to the outer membrane layer. . This cooling mechanism is due to the cooled material used to inflate the device, thereby providing protection to the aortic wall at the level of energy delivery.

  The present invention is also directed to a method for radio frequency (RF) thermal ablation of tissue through the use of one or more circular RF electrodes, which are at the distal end of the catheter within the sheath. Attached to some stretchable part. In the first step of the present invention, the catheter can be inserted into the body through a natural opening, stomach, or a surgically provided opening formed for the purpose of inserting the catheter, , Guide wires, or general purpose support structures or visualization devices. The catheter is advanced through the body to an appropriate location, for example, within the aorta to the location of the renal artery ostium.

  In the next step, the device must be positioned at the renal artery ostium of the aorta. This positioning can be performed by a positioning mechanism, as discussed herein. In one example, the positioning member can help the user confirm the location of the renal artery ostium.

  In the next step of the present invention, after the catheter is in place, a portion of the catheter is stretched, and the stretched portion and the RF electrode attached thereto are placed at the desired branch artery mouth, the aorta. It positions so that it may contact | abut to the inner surface. In one embodiment, the RF electrode is positioned around the renal artery opening to surround the renal artery opening.

  In the next step of the present invention, RF energy is applied to an RF electrode attached to a wire frame or stent to effect a change in the target tissue. Heat is generated by supplying a suitable energy source to the device, the device being composed of at least one electrode in contact with body tissue through a wire frame or stent. Furthermore, coolant (stagnation or circulation) can be employed to cool the inner surface of the vessel wall. This coolant function can provide a form of protection or thermal insulation to the inner wall surface of the vessel during RF energy activation and heat transfer.

  In one embodiment, ablation is performed for ablation of aortic nerve activity that leads specifically to the kidney.

  Other features and advantages of the present invention will become apparent from the following detailed description and drawings. However, it should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are given by way of illustration only, various changes and modifications within the spirit and scope of the invention. However, this detailed description will be apparent to those skilled in the art.

  Embodiments of the present invention will be understood and understood more fully from the following detailed description taken in conjunction with the drawings in which: The drawings are not to scale, and like reference numerals indicate corresponding, similar, or similar elements in the drawings.

1 is a side view of a first embodiment of a device for delivering high frequency energy to a renal artery ostium. FIG. 1 is a side view of a first embodiment of a device for delivering high frequency energy to a renal artery ostium in a deployed posture. FIG. 1 is a front end view of a first embodiment of a device for delivering high frequency energy to a renal artery ostium in a deployed posture. FIG. FIG. 6 is a side view of a second embodiment of a device for delivering high frequency energy to the renal artery ostium.

  As used herein, “proximal” refers to the portion of the instrument that is closer to the operator and “distal” refers to the portion of the instrument that is further away from the operator.

  As used herein, the singular forms also include the plural unless the context clearly indicates otherwise. For example, the term “wire” includes one or more wires and can be considered equivalent to the term “at least one wire”.

  The term “subject” or “patient” refers, in one example, to a mammal, including a human in need of, or receiving such treatment for a medical condition or its sequelae. Subjects or patients may include dogs, cats, pigs, cows, sheep, goats, horses, rats and mice, and humans.

  FIG. 1 is a side view of one embodiment of a device 10 for delivering radio frequency energy to a wall of a body cavity. In one example, radio frequency energy is delivered to the walls of the renal artery or aorta. In one embodiment of device 10, high frequency energy is delivered using a non-conductive catheter.

  In one embodiment, the device 10 is a substantially tubular catheter 12 (referred to as a guide catheter), i.e., a long, narrow, tubular with proximal and distal openings, preferably composed of a non-conductive material. Including devices. Guide catheter 12 may be any type of catheter having a proximal end for steering by an operator and a distal end for manipulation within a patient, as is well known to those skilled in the art. The distal end and proximal end preferably form one continuous piece. In the preferred embodiment, guide catheter 12 is non-conductive. As discussed in more detail below, the guide catheter 12 is used as a delivery system for delivering a balloon catheter that supports high frequency electrodes to a desired site for nerve ablation.

  In one example, the device 10 also includes a cylindrical balloon catheter 14, for example, which is formed from a material such as a polymer, as is well known in the art, which is inflated. This allows the balloon catheter 14 to be stretched in several portions along its length. In one embodiment, the balloon catheter 14 has an outer diameter that is smaller than the inner diameter of the guide catheter 12 when in the undeployed configuration, so that the balloon catheter 14 is easily passed through the guide catheter 12 into the patient. You can proceed to. In certain embodiments, the balloon catheter 14 moves within the guide catheter 12 with low friction relative to the guide catheter 12, so that the guide catheter 12 can be pulled back from the balloon catheter 14 when appropriate. it can.

  In another embodiment, as is known in the art, the balloon catheter 14 has a small diameter annulus passing therethrough which covers the guide wire 16 over the balloon catheter 14. So that it can be advanced through the guide catheter 12, for example, into the patient. In one embodiment, as is known in the art, a guide wire 16, such as a guide wire having a thickness of 0.835 mm (0.035 inches), is first applied to the patient, eg, through the buttocks. It can be inserted into the vasculature and advanced to the desired location. The tubular guide catheter 12 is then inserted into the patient and passed over the guide wire 16 to the desired location. In a preferred embodiment, the device 10 is a rapid exchange (RX) or over-the-wire (OTW) with a guide wire 16 of less than 0.035 inches employed for the device. The-wire wire) or the like is used to advance to a desired location within the patient's vasculature. X-ray contrast media can be injected at the start of the procedure to assist in instrument steering and positioning.

  The balloon catheter 14 is unstretched, for example over a guide wire 16, through the guide catheter 12 to an appropriate location within the body cavity, such as within the aorta, and even within a desired location within the inner circumference of the blood vessel, such as It is advanced longitudinally through the blood vessel into the aortic renal artery ostium. The balloon catheter 14 in the unstretched / non-deployed position may be positioned or encapsulated within the guide catheter 12, which serves as a retractable sheath at the end of the device 10.

  In one embodiment, the balloon catheter 14 is a non-stretchable catheter that generally does not stretch but has one or more different stretchable areas along its length, each section having a different level of stretch. In particular, inflation allows certain portions of the balloon catheter to expand more than other portions of the balloon catheter. For example, as shown in FIG. 1, balloon catheter 14 has sections 14A, 14B, and 14C along its distal end, with each section 14A, 14B, and 14C having a different level of elasticity. Have. In one embodiment, the area 14B of the balloon catheter 14 is formed from a very highly stretchable material that can be stretched, and the areas 14A and 14C of the balloon catheter 14 are very non-stretchable. Formed from a low stretch material. The materials of the areas 14A, 14B, and 14C of the balloon catheter 14 are joined together to form one unitary balloon catheter device 14.

  In another embodiment, the balloon catheter may be a non-stretchable catheter that does not generally stretch but has one or more individual stretchable sections that cover the non-stretchable catheter as a sleeve or overlay. The portions may be extensible individually or individually by expansion. Referring to FIG. 4, in this embodiment, the entire balloon catheter 14 'is formed from a very low stretch material that is essentially non-stretchable (however, in this embodiment, the base catheter is a balloon Can no longer be called true “balloon” catheters since they do not stretch as they stretch). However, balloon catheter 14 'has at its distal end a portion between sections 14A' and 14C ', ie section 14B', which is covered with an annular sleeve-like balloon overlay 15. The balloon overlay 15 is formed from a very high stretch material and can be stretched.

  In a further embodiment, the balloon catheter is a non-stretchable catheter that does not generally stretch but has one or more different stretchable areas along its length, each section having a different level of stretchability. And allowing the balloon catheter to expand a particular portion of the balloon catheter more than the other portions of the balloon catheter, the balloon catheter further comprising one or more individual pieces over the catheter. It also has stretchable portions, which cover stretchable portions may be individually or individually stretchable by expansion.

  The balloon catheter 14 is selectively movable between a non-deployed / non-stretched state and a deployed / stretched state, and is movable to return to the non-deployed / non-stretched state. As shown in FIGS. 1 and 4, in the undeployed state, the balloon catheter 14 of the device 10 is unstretched, i.e., in a collapsed shape, e.g. over the guide wire 16 and through the guide catheter 12. Can be advanced longitudinally through the blood vessel to a suitable location within the body cavity, such as within the aorta, and further to a desired location within the inner circumference of the blood vessel, eg, into the renal artery ostium of the aorta. Once in the desired position, the guide catheter 12 can be withdrawn, exposing the balloon catheter 14.

  After the guide catheter 12 is withdrawn, the balloon catheter 14 can be extended to its deployed position for manipulation within the patient. In the deployed state as shown in FIGS. 2 and 3, the expandable portion of the balloon catheter 14 is expanded. The balloon catheter 14 may have a port 18 as is known in the art, through which air (or another gas) is introduced to allow expansion of its inflatable portion. can do.

  The maximum diameter of the balloon catheter 14 in the deployed state is larger than the inner diameter of the guide catheter 12, so that the balloon catheter 14 can be extended to its deployed state while still being contained within the guide catheter 12. Also, the deployed balloon catheter 14 cannot be pulled back into the guide catheter 12. When it is desired to withdraw the device from the patient after ablation is complete, it is desirable that the balloon catheter 14 be deflated again to the undeployed position for withdrawal back into the guide catheter 12.

  In one embodiment, when the balloon catheter 14 is in the deployed position, as shown in FIG. 2, the stretchable segment of the balloon catheter 14 (area 14B in FIG. 1), the so-called balloon segment, is stretched to a non- Having a much larger diameter than the stretchable segments 14A and 14C, so that the balloon segment 14B has a disc-like configuration with a circular, somewhat flat surface 24, which is a guide wire It is oriented perpendicular to the 16 directions and faces the distal direction. This distally facing surface 24 of the stretched balloon segment 14B provides a cautery surface when contacting the renal artery ostium of the aorta.

  In another embodiment, shown in the undeployed / unstretched state in FIG. 4, when the balloon catheter 14 ′ is stretched to a deployed position similar to that shown in FIG. 2, the balloon catheter 14 in FIG. The individually stretchable annular balloon portion 15 (so-called balloon overlay) covering the 'region 14B' is stretched to have a much larger diameter than the non-stretchable segments 14A 'and 14C', thereby The overlay 25 has a disk-like configuration with a circular, somewhat flat surface, similar to that shown in FIG. 2, which is oriented perpendicular to the direction of the guide wire 16 and in the distal direction Facing. This distally facing surface of the stretched balloon overlay 25 provides a cautery surface when contacting the renal artery ostium of the aorta.

  In one example, the balloon catheter 14 of the device 10 includes one or more electrodes 20, which are capable of conducting RF energy and are in contact with body tissue. In one example, the one or more electrodes 20 are positioned in a circular configuration over a portion of the balloon catheter 14 when the device 10 is in its deployed position, so that the electrodes 20 Essentially 360 °. When multiple electrodes 20 are used, the electrodes 20 have a generally circular configuration or are concentrically oriented when the device 10 is in the deployed position, thereby essentially surrounding the target area as a whole. The electrode 20 can be positioned so as to surround 360 °.

  When the balloon catheter 14 is in its deployed position, as shown in FIGS. 2 and 3, the one or more electrodes 20 are in contact with the balloon segment 14B of the device 10 when the device 10 is in its deployed position. Located above, ie on the distally facing surface 24 of the stretched balloon segment 14B (or stretched balloon overlay 15). This distally facing surface 24 of the balloon segment 14B can be pushed into contact with the inner surface of the aorta at the junction of the renal arteries, so that, for example, the electrode 20 positioned in a circular configuration is in contact with the aorta. Located around the renal artery ostium. When the electrode 20 is brought into contact with the inner surface of a lumen such as the aorta, for example, at the renal artery opening, the nerve activity is cauterized in the circumferential direction around the renal artery opening.

  As shown in FIG. 1, an RF electrode 20 is attached to the balloon catheter 14 to deliver RF energy to the body cavity and as a means for sensing temperature and neural activity. In certain embodiments, the device 10 has a number of RF electrodes 20 that are individually attached to the surface of the balloon catheter 14, but when directed together in a deployed configuration, the balloon segment Positioned in a circular configuration on the distally facing surface 24 of 14B. In one embodiment, as shown in FIG. 3, the device 10 has four arc-shaped electrodes 20. In one embodiment, electrode 20 is attached to and positioned outside of balloon catheter 14 at segment 14B. In another embodiment, electrode 20 is attached to and positioned on balloon overlay 15.

  When the balloon catheter 14 is in its undeployed configuration, the RF electrode 20 is substantially flat with respect to the surface of the balloon catheter 14 and has a relatively low shape with respect to the surface of the balloon catheter 14. The electrode 20 can be attached to the surface of the balloon segment of the balloon catheter, for example, by gluing, bonding, or wire cage attachment. Thus, when the balloon catheter 14 is advanced distally through the guide catheter 12 for use within the patient, or the balloon catheter 14 is proximally through the guide catheter 12 for withdrawal from the patient. When advanced, the RF electrode 20 does not interfere with or interfere with the progression of the balloon catheter 14 through the guide catheter 12.

  As shown in FIG. 1, when the balloon catheter 14 is in its undeployed configuration, the four arc-shaped electrodes 20 are in a superimposed relationship with each other. Then, when the balloon catheter 14 is extended to its deployed configuration, the four arc-shaped electrodes 20 slide or slide over each other and are directed into a circular configuration as shown in FIG. In this configuration, the electrode 20 may have attachment means that loosely connect the electrode 20 to the surface of the balloon catheter 14 and when the balloon catheter 14 is deflated into its undeployed configuration. This assists in repositioning the electrodes 20 and returning them to their resting configuration. This attachment also ensures proper fixation of the electrode 20 to the surface of the balloon catheter 14. In one embodiment shown in FIG. 3, the attachment means may be a shape memory wire 26, which is on the surface of the balloon segment 14B of the balloon catheter 14 when the balloon catheter 14 is deflated. It helps to reposition the electrodes 20 relative to each other.

  In one embodiment, there is one or more elongated wires (not shown) that are balloons to which the RF electrodes 20 are attached to conduct RF energy from the external RF control unit to the RF electrodes 20. It extends along the side of the catheter 14. In one embodiment, all RF electrodes 20 are attached to the same wire and are thereby configured to operate simultaneously. The electrode 20 may also have a wire that loosely connects the electrodes to electrically connect the electrodes. In another embodiment, there are multiple wires, and each wire is attached to only one electrode 20, thereby conducting RF energy from the RF control unit to individual RF electrodes 20. The RF electrodes 20 can deliver their energy simultaneously or can deliver energy sequentially or in other desired patterns.

  When the balloon catheter 14 is changed to its deployed position by inflation, the electrode 20 positioned on the surface of the balloon catheter 14 is positioned on the distally facing surface 24 of the balloon segment 14B. The purpose of positioning the electrode 20 on one side of the distally facing surface 24 of the balloon segment 14B is to position the electrode 20 in contact with the renal artery ostium, eg, for more effective ablation of the renal nerve, or To be able to push it up. The guide catheter 12 is advanced distally and the distal edge of the guide catheter 12 strikes the proximally facing surface of the stretched balloon segment 14B, thereby distant the stretched balloon segment 24. The RF electrode 20 on the surface 24 facing the distal side is pushed distally so that it can be positioned in contact with the renal artery ostium and the electrodes 20 can perform their cauterization function. When the distal electrode support surface 24 of the balloon segment 14B is pushed up against the renal artery ostium of the aorta, the electrode 20 positioned in a circular configuration is configured to contact the renal artery ostium of the aorta. Sometimes. Then, by supplying a suitable RF energy source to the device 10, heat is generated at the electrode 20 and ablation is performed for ablation of neural activity, such as neural activity that leads specifically to the kidney.

  In one example, the device 10 includes a positioning element or mechanism for positioning and securing the device 10 at a desired location within a blood vessel, eg, the aorta. Such a mechanism is necessary to allow the electrode 20 to operate in the correct position, ie around the renal artery ostium. Conversely, if the device 10 is not properly positioned, the electrode 20 cauterizes tissue that is not intended to cause injury and causes irreparable damage. In embodiments where the RF electrode 20 is configured in a circle, the positioning mechanism should properly center the electrode 20 circumferentially around the renal artery ostium, ie, the opening to the renal artery.

  In a first example, the positioning mechanism comprises a guide wire 16 and a non-stretched area 14A distal to the balloon catheter 14, which is at least partially inserted at the entrance to the renal artery. And stay there. After this is done, the guide catheter 12 over the balloon catheter 14 is withdrawn proximally and then the balloon segment 14B of the balloon catheter 14 is inflated. The guide catheter 12 is then advanced distally and the distal edge of the guide catheter 12 strikes the proximally facing surface of the expanded balloon segment 14B, thereby expanding the expanded balloon segment 14B. The RF electrodes 20 on the distally facing surface 24 of the device can be positioned to contact the renal artery ostium and allow the electrodes 20 to perform their cauterization function.

  In another embodiment, the positioning mechanism comprises a separately expandable portion of the balloon catheter 14, ie, the area 14A of the balloon catheter 14 that is located distal to the balloon segment 14B. In this embodiment, the area 14A of the balloon catheter 14 is individually inflatable and is referred to as a positioning segment because it projects to the entrance to the renal artery. This positioning segment 14A of the balloon catheter 14 is inserted at least partially into the renal artery entrance and then inflated only to approximately the diameter of the renal artery, not the size of the balloon segment 14B, so that the balloon The catheter 14 is prevented from moving distally or proximally relative to the renal artery, allowing the device 10 to maintain its position within the renal artery relative to the aorta. When the device 10 is so positioned by the inflatable balloon at the positioning segment 14A of the balloon catheter 14, the circularly configured RF electrode 20 can be positioned to contact the renal artery ostium, thereby allowing RF The electrodes 20 can perform their cauterization function. In one embodiment, before the positioning segment 14A of the balloon catheter 14 is expanded, the distal edge of the guide catheter 12 strikes the proximally facing surface of the expanded balloon segment 14B, thereby The RF electrode 20 on the distal facing surface 24 of the expanded balloon segment 14B is positioned to contact the renal artery ostium.

  In certain embodiments, the positioning mechanism comprises an unstretched area of the balloon catheter 14 at its distal end and can also comprise an individually inflatable portion located distal to the balloon segment. The non-stretched area of the balloon catheter 14 can be inserted at least partially at the entrance to the renal artery to help guide the device to the proper location within the aorta. The inflatable portion can be inflated within the renal artery, thereby maintaining the position of the device within the renal artery relative to the aorta.

  In one example, the positioning mechanism includes an imaging catheter at the distal end of the balloon catheter 14 that allows the user to accurately view the location of the renal artery ostium by the use of visual means; The device can be properly positioned within the renal artery. In one embodiment, the imaging catheter is external to the patient and includes a proximal end that is steered by the user along with the operating end of the device and a distal end located at the distal end of the balloon catheter 14 Also equipped.

  In these examples, the positioning element or mechanism operates to position the balloon catheter 14 within the renal artery, thereby allowing the circularly configured RF electrode 20 to be pressed against the renal artery ostium, Specifically, it can be pressed around the opening from the renal artery opening to the branched renal artery. This can be accomplished by either unloading the distal end of the balloon catheter 14 or the distal end of the imaging catheter to the kidney so that it can act as a fixture for the device 10 inside the aorta by itself or by inflation of a balloon exposed from the inside. This is accomplished by at least partial insertion at the arterial entrance so that the RF electrodes 20 can perform their ablation function.

  Device 10 includes at its proximal end at least one port 18 for connection to a radio frequency (RF) power source. Device 10 can be coupled to a radio frequency (RF) energy source, for example, an RF energy source in the range of about 300 kilohertz to 500 kilohertz. The electrode is electrically coupled to the RF energy source through this port. Device 10 can be coupled to an air source for inflation of the inflatable portion of balloon catheter 14. The device 10 can also be connected to a control unit for sensing and measuring other factors such as temperature, conductivity, pressure, impedance, and other variables such as nerve energy.

  Device 10 can also be connected to an air source or fluid source via port 18 or a second port. This port can be pneumatically or hydraulically coupled to a pump or other device for inflation and deflation of the inflatable portion of the balloon catheter 14. The port can also be used for inflation and deflation when a balloon overlay of the balloon catheter 14 'is present. In addition, the ports can be used for inflation and deflation of balloons used in positioning mechanisms. There may be one port for all balloons, or there may be individual ports for one or more balloons. This same port can be used to circulate coolant inside the balloon for the purpose of cooling the balloon during RF energy activation.

  In one example, the RF electrode 20 operates to provide radio frequency energy to heat the desired location during a nerve ablation procedure. The electrode can be composed of any suitable conductive material, as is known in the art. Examples include stainless steel and platinum alloys.

  The RF electrode 20 can operate with a ground pad electrode in bipolar or monopolar mode. In the unipolar mode of delivering RF energy, a single electrode is used in combination with a neutral electrode patch that is affixed to the body to form the other electrical contact and complete the electrical circuit. Bipolar operation is possible when more than one electrode is used, for example two concentric electrodes. Electrode 20 can be attached to an electrode delivery member, such as a wire frame, by use of soldering or welding methods well known to those skilled in the art.

  In embodiments where one or more arc-shaped RF electrodes 20 are oriented in a circular configuration, the diameter of the circular or arc-shaped RF electrode 20 is determined by the width of the aortic branch where denervation is desired. If the RF electrode diameter is smaller than the diameter of the aortic branch where denervation is desired, the RF electrode is not actually in contact with the tissue and ablation is not performed. For example, when aortic denervation is desired at the level of the renal artery ostium (approximately 6-7 mm in diameter at the aortic ostium), in order to adequately provide ablation surrounding the renal arterial ostium, the diameter of the circular RF electrode is at least its Must be length, ie 7 mm. In another embodiment, the length of each of the four arc-shaped electrodes 20 is about 2-3 mm.

  In another example, the diameter of the RF electrode 20 can be calculated with respect to the renal artery ostium. For example, if RF energy is desired to be applied at least about 2 mm from each edge of the renal artery ostium, the RF electrode surrounding the imaging catheter has a diameter of 10-14 mm to May surround.

  Each electrode 20 can be arranged to treat tissue by delivering radio frequency (RF) energy. The radio frequency energy delivered to the electrode has a frequency of about 5 kHz (kilohertz) to about 1 GHz. In a specific embodiment, the RF energy is at a frequency of about 10 kHz to about 1000 MHz, specifically about 10 kHz to about 10 MHz, more specifically about 50 kHz to about 1 MHz, and more specifically about 300 kHz to about 500 kHz. May have a frequency of

  In the preferred embodiment, the electrodes 20 can be operated individually or in combination with each other as a series of electrodes arranged in an array. Selective electrode operation can direct treatment to a single region or multiple different regions of the blood vessel.

  The electrode selection and control switch can include elements arranged to select and activate individual electrodes.

  The RF power supply can have multiple channels and deliver individually regulated power to each electrode. This reduces the preferential heating that occurs when more energy is delivered to the larger conductivity area, and less heating occurs around the electrodes placed in the smaller conductivity tissue. If the level of tissue hydration or blood injection rate within the tissue is uniform, a single channel RF power source can be used to provide an output to generate a relatively uniform lesion.

  The RF energy delivered to the tissue through the electrodes causes tissue heating due to the tissue absorbing RF energy and ohmic heating due to tissue electrical resistance. This heating can cause injury to the affected cells and can be large enough to cause cell death (a phenomenon also called cell necrosis). To facilitate the following discussion of this application, cytotoxicity includes all cellular effects due to the delivery of energy from the electrode, including cell necrosis. Cytotoxicity can be achieved as a relatively simple medical procedure using local anesthesia. In one example, the cell injury progresses to a depth of about 1-5 mm from the surface of the mucosal layer of the sphincter or adjacent anatomical structure.

  In certain embodiments, the balloon catheter 14 is insulated between each RF electrode 20 and the surface of the balloon catheter 14 to protect the balloon catheter 14 from, for example, direct effects of RF energy. Provide a pad. In another example, the balloon catheter 14 can include circulating coolant to cool the balloon and protect it from the direct effects of RF energy.

  The design also includes means for measuring renal nerve afferent activity before and after RF nerve ablation. Measuring renal nerve activity after treatment provides a certainty that proper nerve ablation has been achieved. Renal nerve activity is measured by the same mechanism required for energy delivery and by electrodes on a positioning balloon placed in the renal artery.

  Neural activity can be measured by one of two means. Proximal renal nerve stimulation is performed by transmitting electrical pulses to a catheter positioned within the proximal segment of the renal artery. The action potential is measured from a segment of the catheter located inside the more distal portion of the renal artery. The amount of downstream electrical activity and the time delay of electrical activity from the proximal electrode to the distal electrode provides a measure of residual neural activity after nerve ablation. A second means of measuring renal nerve activity is to measure ambient electrical pulses before and after nerve ablation within a more distal site within the renal artery.

  In another embodiment, the RF electrode 20 operates to provide high frequency energy for both heat sensing and temperature sensing. Thus, in this example, the RF element can be used for heating during an ablation procedure, and can also be used for sensing neural activity before and after ablation.

  Each electrode 20 can be coupled to at least one sensor or control unit capable of measuring factors such as temperature, conductivity, pressure, impedance, and other variables. For example, the device may have a thermistor that measures the temperature in the lumen, which may be a component of a microprocessor-controlled system that receives temperature information from the thermistor, Adjust the frequency, duration of energy delivery, or total energy delivered to the electrode.

  The device 10 can be coupled to a visualization device such as a fiber optic device, a fluoroscopic device, an anoscope, a laparoscope, an endoscope. In one example, the device coupled to the visualization device is controlled from a position outside the body, for example, by an instrument in the operating room or by an external device for maneuvering the inserted catheter.

  In another example, the device 10 can be configured with markers that help the operator achieve the desired placement, such as radiopaque markers, etching, or microgrooves. Thus, the device 10 can be configured to improve its image clarity by techniques such as ultrasound, CAT scan, or MRI. In addition, an x-ray contrast agent can be injected through the injection port and through the hollow interior of the catheter, thereby allowing localization by fluoroscopy or angiography.

  The invention herein also includes a method for performing ablation of renal arterial nerve function within the aorta using the devices described hereinabove. This method is performed by a system that includes the device 10 and a control assembly (not shown). Although the method is described sequentially, the steps of the method can be performed simultaneously or concurrently by separate elements, whether asynchronous, pipelined, or otherwise. Except as otherwise noted, the method need not be performed in the same order as the steps are listed in this description.

  At point a of the flow, the electrical energy port is coupled to the electrical energy source. The patient is placed on the treatment table in a posture suitable for insertion of the catheter.

  In step b, the visualization port is coupled to a suitable visualization device, such as a fluoroscope, endoscope, display screen, or other visualization device. The selection of the visualization device depends on the judgment of the medical staff.

  In step c, the therapy energy port is coupled to an RF energy source.

  In step d, the aspiration and inflation device is coupled to the irrigation and inhalation control port so that the catheter balloon can then be inflated.

  At step e, the guide wire 16 and guide catheter 12 or tube are lubricated and introduced into the patient. The insertion may be percutaneous, inserted through a surgically formed arteriotomy, or inserted by an open surgical procedure.

  In step f, the most distal end of the balloon catheter 14 is lubricated and introduced into the patient. In the preferred embodiment, the balloon is fully deflated during insertion. The balloon catheter 14 can be inserted into the body cavity via its outer surface and is passed through the blood vessel until the balloon portion is positioned adjacent to the blood vessel to be treated.

  In step g, the position of device 10 is checked using a visualization device coupled to the visualization port. This device can be continuously monitored by medical professionals throughout the procedure.

  At step h, the positioning mechanism (if used) is positioned to project into the renal artery ostium or another arterial ostium.

  At step i, the guide catheter 12 is pulled back to allow the balloon catheter 14 to be inflated.

  In step j, the irrigation and suction control port is manipulated to inflate the positioning mechanism balloon to stabilize the position of the device 10 within the lumen and to inflate the balloon segment 14B of the balloon catheter 14.

  At step k, the guide catheter 12 is advanced distally so that the distal-most edge of the guide catheter 12 strikes the proximal facing surface of the stretched balloon segment 14B and is stretched. The distal facing surface 24 of the balloon segment 14B is pressed against the renal artery ostium.

  In step l, the electrode 20 on the distal facing surface 24 of the stretched balloon segment 14B is selected using an electrode selection and control switch. In the preferred embodiment, all electrodes 20 are deployed at once. In another preferred embodiment, the electrodes 20 can be selected individually. This step can be repeated at any time before step l.

  In step m, the therapy energy port is manipulated to cause the release of energy from the electrode 20. The duration and frequency of energy are at the discretion of the healthcare professional. This release of energy creates a circular pattern of lesions at the renal artery ostium.

  At step n, the irrigation and inhalation control port is operated to deflate the positioning device balloon and balloon segment 14B.

  At step o, the guide catheter 12 is advanced over the deflated balloon catheter 14.

  At step p, the positioning device balloon catheter 14 is pulled back into the guide catheter 12 from the renal artery ostium.

  In step q, the guide catheter 12 is withdrawn from the patient.

  While the preferred embodiment of the invention has been described with reference to the accompanying drawings, the invention is not limited to the embodiment itself but departs from the scope or spirit of the invention as defined in the appended claims. It should be understood that various changes and modifications can be made by those skilled in the art.

Claims (24)

A balloon catheter having at least one inflatable portion, said inflatable portion having a larger diameter when inflated than when not inflated and having a flat surface facing distally. A balloon catheter,
At least one radio frequency electrode positioned on an outer surface of the at least one inflatable portion of the balloon catheter, the at least one radio frequency electrode being inflated when the inflatable balloon catheter portion is inflated; A neuroablation device having a radiofrequency electrode positioned to assume a circular configuration on the distally facing flat surface of the inflatable balloon catheter portion.   The nerve ablation device according to claim 1, wherein each said at least one inflatable portion has a different level of elasticity than an adjacent inflatable portion and is individually inflatable.   The nerve ablation device of claim 1, wherein each said at least one inflatable portion has an inflatable balloon that covers a non-inflatable portion of the balloon catheter and is individually inflatable.   The nerve ablation device of claim 1, wherein the device is movable between a non-deployed position and a deployed position.   The nerve ablation device according to claim 4, wherein the balloon catheter is not inflated when the device is in the undeployed position, and the balloon catheter is inflated when the device is in the deployed position.   6. The balloon catheter can be longitudinally advanced to a desired position within a body cavity over a guide wire and through an annular guide catheter when the device is in the undeployed position. Nerve ablation device.   7. The nerve ablation device of claim 6, wherein when the device is in a desired position within a body cavity, the guide catheter can be pulled back to expose the balloon catheter.   8. The nerve ablation device of claim 7, wherein the at least one radio frequency electrode on the distally facing flat surface can contact body tissue after the expandable portion of the balloon catheter has been stretched. device.   When inflated, the at least one inflatable portion of the balloon catheter has a proximally facing surface, and the annular guide catheter is distal to the proximally facing flat surface. 8. The nerve ablation device of claim 7, wherein the nerve ablation device can be pressed against the body tissue with the at least one radio frequency electrode on the distally facing flat surface.   The nerve ablation device according to claim 1, wherein the at least one radio frequency electrode is capable of conducting RF energy to contacting body tissue.   The nerve ablation device according to claim 1, wherein the at least one radio frequency electrode can be attached to an outer surface of the at least one inflatable portion of the balloon catheter by a shape memory material.   The at least one radio frequency electrode is positioned in a superimposed relationship with each other on the outer surface of the inflatable portion of the balloon catheter when the inflatable balloon catheter portion is not inflated, and the inflatable balloon catheter The nerve ablation device of claim 1, wherein when the portion is inflated, it can move to the circular configuration on the distally facing flat surface.   The nerve ablation device of claim 1, further comprising a positioning mechanism.   14. The nerve ablation device according to claim 13, wherein the positioning mechanism comprises an expandable balloon.   15. The nerve ablation device according to claim 14, wherein the expandable balloon has a second inflatable portion of the balloon catheter positioned distal to the at least one inflatable portion.   The nerve ablation device according to claim 1, further comprising at least one port, wherein the at least one port is used for balloon inflation and / or for connection to a control unit. A method for ablating nerves at the arterial ostium of a subject's aorta when necessary,
Inserting a balloon catheter into the aorta, the balloon catheter comprising: (a) a flat surface having a larger diameter when inflated than when not inflated and facing distally; At least one inflatable portion, and (b) the at least one inflatable to assume a circular configuration on the distally facing flat surface when the inflatable balloon catheter portion is inflated. Having at least one high-frequency electrode positioned on the outer surface of the portion;
Inflating the inflatable portion of the balloon catheter;
Positioning the circularly configured at least one high-frequency electrode around an aortic ostium of the aorta;
Delivering high frequency energy to a designated location within the renal artery wall via at least one high frequency electrode.   18. The method of claim 17, wherein inflating the inflatable portion comprises inflating an inflatable balloon that covers a non-inflatable portion of the balloon catheter.   18. The method of claim 17, further comprising the step of longitudinally advancing the balloon catheter over a guide wire through the annular guide catheter to a desired location within the body cavity.   20. The method of claim 19, further comprising pulling back the guide catheter to expose the balloon catheter prior to the step of inflating the inflatable portion of the balloon catheter.   Contacting the at least one radio frequency electrode on the distally facing flat surface with body tissue at the aortic ostia after the inflatable portion of the balloon catheter is stretched. Item 18. The method according to Item 17.   The at least one inflatable portion of the balloon catheter when inflated has a proximally facing surface, and the step of contacting the guide catheter against the proximally facing flat surface 24. The method of claim 21, comprising pushing distally, thereby contacting the body tissue with the at least one radio frequency electrode on the distally facing flat surface.   18. The method of claim 17, further comprising positioning the balloon catheter within the aorta prior to inflating the inflatable portion.   The method of claim 17, wherein the positioning comprises inflating a second inflatable portion of the balloon catheter positioned distal to the at least one inflatable portion within the aorta.

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