Lesion-crossing shockwave catheter

Abstract

The present invention provides a catheter for treating an occlusion in a blood vessel. An exemplary catheter for treating an occlusion in a blood vessel includes a tubular inner member including a base segment with a first lumen defining a fluid inlet port and a second lumen defining a fluid outlet port. An extension segment is distal to the base segment. The extension segment has a reduced cross-section. An emitter assembly includes a first insulated wire extending through the second lumen, a second insulated wire, and a conductive sheath wrapped around the first insulated wire, the second insulated wire, and the extension segment. A cap or balloon is sealably attached to the distal end of the catheter and surrounds the emitter assembly, and the cap or balloon is fillable with a conductive fluid.

Description

[Technical Field]

[0001] (Priority) This application claims priority to U.S. Provisional Patent Application No. 63 / 124,639, filed December 11, 2020, and U.S. Non-Provisional Patent Application No. 17 / 537,325, filed November 29, 2021, the entire disclosures of which are incorporated by reference.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to a catheter device that can be used to cross calcified lesions. The catheter includes a distal shockwave generator configured with a very low profile to enable advancement through narrow vasculature. [Background technology]

[0003] A wide variety of catheters have been developed to treat arterial disease. For example, treatment systems for percutaneous coronary intervention or peripheral angioplasty use angioplasty balloons to open lesions (e.g., calcified lesions) and restore normal blood flow within the artery. In these types of procedures, a catheter carrying a balloon is advanced into the vessel along a guidewire until the balloon is aligned with the calcified plaque. The balloon is then pressurized, shrinking or destroying the calcified plaque and forcing it back against the vessel wall. The balloon can have a smooth wall or can be equipped with structures that physically cut a lesion within the vessel. Other catheters, known as atherectomy resection devices, have a rotating element to puncture and remove the lesion.

[0004] More recently, catheters have been developed that include one or more electrode pairs positioned inside an angioplasty balloon. In these devices, the catheter is advanced over a guidewire within the patient's vasculature until it is proximal to the lesion. The balloon is inflated with a conductive fluid to contact the lesion, and then a shockwave generator is fired to produce shockwaves that direct acoustic waves into the lesion. Shockwave devices are particularly effective for treating calcified lesions because the acoustic waves can disrupt the lesion without harming the surrounding vessels. Once the lesion is disrupted, the balloon can be further expanded within the vessel to create an improved blood flow lumen.

[0005] The shock wave generator is typically an electrode pair that is excited by the application of a high-voltage pulse. Attempts have been made to reduce the size of the electrode pair, allowing access to more rigid and difficult-to-cross calcified lesions. Examples of such low-profile designs can be found in U.S. Patent Nos. 8,747,416 and 10,555,744 and U.S. Publication Nos. 2018 / 0360482 and 2019 / 0150960 (all of which are incorporated herein by reference).

[0006] While the low-profile designs discussed above have been deployed in both coronary and peripheral vascular applications, even these designs have difficulty crossing partial or complete occlusions within the vessel. One approach to addressing this problem is to use a guidewire with a shockwave generator at its distal tip. In this case, the proximal and distal shaft portions of the catheter are reinforced to aid in the advancement of the guidewire into the occlusion. One or more shockwaves are generated to partially open the blockage. The guidewire can then be advanced further into the occlusion, and additional shockwaves are generated within the occlusion. This sequence can be continued to move the guidewire through the occlusion and provide a sufficiently large channel through which a balloon catheter can be inserted. An example of such a shockwave guidewire design can be found in U.S. Pat. No. 9,730,715 (incorporated herein by reference).

[0007] Although placing the shock wave electrode at the tip of a guidewire can lead to an extremely thin structure, such an approach has several disadvantages compared to thin designs that include an inflatable balloon. For example, the guidewire necessarily has a soft tip that cannot be easily pushed through obstructions. In addition, the guidewire design is monopolar, with one electrode at the tip of the guidewire and a second electrode defined by a pad attached to the patient's body. This means that the patient is part of the electrical circuit. In addition, the guidewire design does not have a balloon at the tip. A balloon is advantageous in that it can protect tissue from direct contact with the plasma generated during shock wave generation. The balloon also ensures that a conductive fluid surrounds the electrode during shock wave generation.

[0008] Therefore, a need exists to provide a catheter design that incorporates a low-profile cap or a low-profile angioplasty balloon, includes a bipolar electrical circuit for generating shock waves inside the cap or balloon, and has a lower profile than previous approaches. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] U.S. Patent No. 8,747,416 [Patent Document 2] U.S. Patent No. 9,730,715 Summary of the Invention [Means for solving the problem]

[0010] The above objectives are realized in a catheter for treating occlusions in blood vessels having at least one electrode pair inside a low-profile cap or angioplasty balloon at the distal end of the catheter. In some designs, the electrodes are coplanar, reducing the diameter of the device. In addition, a low-profile cap or balloon is used that does not need to be folded before insertion into the cardiovascular system. Such a cap or balloon can be expanded a relatively small amount, enough to immerse the electrodes in a conductive fluid, before generating shock waves at the electrodes to treat the occlusion. The cap or balloon can be made of a material with elastomeric properties so that it returns to its original low-profile configuration when deflated following treatment.

[0011] An exemplary catheter for treating an occlusion in a blood vessel includes a tubular inner member including a base segment defining a first lumen defining a fluid inlet port and a second lumen defining a fluid outlet port, an extension segment distal to the base segment, the extension segment having a reduced cross-section relative to the base segment, an emitter assembly including a first insulated wire extending through the second lumen, a second insulated wire, and a conductive sheath wrapped circumferentially around the first insulated wire, the second insulated wire, and the extension segment, and a cap or balloon sealably attached to the distal end of the catheter and surrounding the emitter assembly, the cap or balloon being fillable with a conductive fluid.

[0012] In some embodiments, the extension segment is configured to receive a guidewire.

[0013] In some embodiments, the extension segment is connected to a third lumen in the base segment, and the extension segment is formed by removing the walls of the first and second lumens at the distal end of the inner member.

[0014] In some embodiments, the fluid inlet port comprises tubing extending from the first lumen.

[0015] In some embodiments, the second wire extends through the first lumen.

[0016] In some embodiments, the distal end of the first lumen is sealed to expose only a portion of the second wire and a portion of the tubing.

[0017] In some embodiments, the conductive fluid is configured to flow around the conductive sheath and exit through a gap formed by the outside of the conductive sheath and the second lumen.

[0018] In some embodiments, the emitter assembly includes a first electrode pair including a conductive sheath and a conductive distal end of a first insulated wire spaced apart from the conductive sheath, and a second electrode pair including a conductive sheath and a conductive distal end of a second insulated wire spaced apart from the conductive sheath.

[0019] In some embodiments, the first electrode pair and the second electrode pair are positioned approximately 180 degrees circumferentially apart around the conductive sheath.

[0020] In some embodiments, the proximal ends of the first wire and the second wire are connectable to a pulsed voltage source.

[0021] In some embodiments, the catheter further comprises a reinforcing wire sheath wrapped circumferentially around the inner member sheath.

[0022] In some embodiments, the reinforcing wire sheath comprises at least one braided or coiled metal wire encapsulated in a polymer.

[0023] In some embodiments, the cap or balloon is flexible and can be expanded by inflation with a conductive fluid, and the maximum inflated diameter of the flexible cap or balloon exceeds the contracted diameter of the flexible cap by no more than 15%.

[0024] In some embodiments, the cap or balloon is made from a material that has elastomeric properties so that after being inflated, the cap or balloon returns to a low-profile configuration when deflated.

[0025] In some embodiments, the cap comprises an extruded polymer tube.

[0026] In some embodiments, when the balloon is in a deflated state, the surface area of ​​the balloon is small enough that the balloon does not collapse when the catheter is advanced into the blood vessel.

[0027] In some embodiments, the first wire and the second wire are flattened.

[0028] In some embodiments, the first wire or the second wire comprises at least one of copper and stainless steel.

[0029] In some embodiments, the conductive sheath is oval in shape.

[0030] In some embodiments, the catheter further comprises a soft tip that tapers toward the distal end of the catheter.

[0031] In some embodiments, the catheter includes a tubular inner member having a proximal portion with a first diameter and a distal end portion with a second diameter smaller than the first diameter, the proximal portion of the inner member including four circumferentially positioned longitudinal grooves, each longitudinal groove receiving one of four tubes. A first wire is located within the first tube and extends distally beyond the first tube. A second wire is located within the second tube and extends distally beyond the second tube. A third tube is connectable to a source of conductive fluid, and a fourth tube is configured to define a return path for the conductive fluid. A cylindrical insulating sheath is positioned around the distal portion of the inner member and radially inward of the distal ends of the first and second wires. A cylindrical conductive sheath surrounds the distal ends of the first and second wires and defines two electrode pairs. A sheath surrounds the proximal portion of the inner member. A flexible cap surrounds the conductive sheath and the distal tip of the catheter. The present invention provides, for example, the following items. (Item 1) 1. A catheter for treating an occlusion in a blood vessel, the catheter comprising: A tubular inner member, the tubular inner member comprising: a base segment, the base segment comprising: a first lumen defining a fluid inlet port; a second lumen defining a fluid exit port; a base segment defining a an extension segment distal to the base segment, the extension segment having a reduced cross section than the base segment; an inner tubular member comprising: 1. An emitter assembly, the emitter assembly comprising: a first insulated wire extending through the second lumen; a second insulated wire; a conductive sheath wrapped circumferentially around the first insulated wire, the second insulated wire, and the extension segment; an emitter assembly comprising: a cap or balloon sealably attached to the distal end of the catheter and surrounding the emitter assembly; Equipped with A catheter wherein the cap or balloon is fillable with a conductive fluid. (Item 2) Item 10. The catheter of item 1, wherein the extension segment is configured to receive a guidewire. (Item 3) Item 1, wherein the extension segment is connected to a third lumen within the base segment, and the extension segment is formed by removing walls of the first lumen and the second lumen at the distal end of the inner member. (Item 4) Item 10. The catheter of item 1, wherein the fluid inlet port comprises tubing extending from the first lumen. (Item 5) 5. The catheter of claim 4, wherein the second wire extends through the first lumen. (Item 6) 6. The catheter of claim 5, wherein the distal end of the first lumen is sealed to expose only a portion of the second wire and a portion of the tubing. (Item 7) Item 1, wherein the conductive fluid is configured to flow around the conductive sheath and exit through a gap formed by the outside of the conductive sheath and the second lumen. (Item 8) The emitter assembly includes: a first electrode pair comprising the conductive sheath and a conductive distal end of the first insulated wire spaced from the conductive sheath; a second electrode pair comprising the conductive sheath and a conductive distal end of the second insulated wire spaced from the conductive sheath; Item 1. The catheter according to item 1, comprising: (Item 9) 9. The catheter of claim 8, wherein the first electrode pair and the second electrode pair are positioned approximately 180 degrees apart circumferentially around the conductive sheath. (Item 10) Item 1, wherein the proximal ends of the first wire and the second wire are connectable to a pulsed voltage source. (Item 11) Item 14. The catheter of item 1, further comprising a reinforcing wire sheath wrapped circumferentially around the inner member sheath. (Item 12) Item 12. The catheter of item 11, wherein the reinforcing wire sheath comprises at least one braided or coiled metal wire encapsulated in a polymer. (Item 13) Item 1. The catheter of item 1, wherein the cap or balloon is flexible and can be expanded by inflation with the conductive fluid, and the maximum inflated diameter of the flexible cap or balloon is no more than 15% larger than the deflated diameter of the flexible cap. (Item 14) Item 1, wherein the cap or balloon is made from a material having elastomeric properties so that after being inflated, the cap or balloon returns to a low-profile configuration when deflated. (Item 15) Item 10. The catheter of item 1, wherein the cap comprises an extruded polymer tube. (Item 16) Item 1. The catheter of item 1, wherein a balloon is attached to the distal end of the catheter, and when the balloon is in a deflated state, the surface area of ​​the balloon is sufficiently small so that the balloon does not fold when the catheter is advanced into a blood vessel. (Item 17) Item 1, wherein the first wire and the second wire are flattened. (Item 18) Item 10. The catheter of item 1, wherein the conductive sheath is oval. (Item 19) Item 14. The catheter of item 1, further comprising a soft tip that tapers toward the distal end of the catheter. (Item 20) 1. A catheter for treating an occlusion in a blood vessel, the catheter comprising: a tubular inner member having a proximal portion with a first diameter and a distal end portion having a second diameter smaller than the first diameter, the proximal portion of the inner member including four circumferentially positioned longitudinal grooves, each longitudinal groove receiving one of the four tubes; a first wire located within the first tube and extending distally beyond the first tube; a second wire located within the second tube and extending distally beyond the second tube; a third tube connectable to a source of conductive fluid; a fourth tube configured to define a return path for the conductive fluid; a cylindrical insulating sheath positioned around the distal portion of the inner member and radially inward of the distal ends of the first and second wires; a cylindrical conductive sheath surrounding the distal ends of the first and second wires and defining two electrode pairs; a sheath surrounding a proximal portion of the inner member; a flexible cap surrounding the conductive sheath and the distal tip of the catheter; A catheter comprising: (Item 21) 21. The catheter of claim 20, wherein the inner member is formed from a single extrusion. (Item 22) 21. The catheter of claim 20, wherein the fourth tube is connectable to a source of suction. (Item 23) 21. The catheter of claim 20, wherein the outer sheath is a wire braid. (Item 24) 21. The catheter of claim 20, wherein the inner member further comprises a central guidewire lumen. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is an illustration of a shock wave angioplasty catheter being used to treat an obstruction in a blood vessel according to some embodiments of the subject invention.

[0033] [Figure 2A] FIG. 2A is an illustration of components at the distal end of a catheter according to some embodiments of the subject invention.

[0034] [Figure 2B] FIG. 2B is an illustration of components at the distal end of a catheter according to some embodiments of the subject invention.

[0035] [Figure 2C] FIG. 2C is an illustration of components at the distal end of a catheter according to some embodiments of the subject invention.

[0036] [Figure 2D]FIG. 2D is an illustration of an exploded perspective view of a distal section of a catheter according to some embodiments of the subject invention.

[0037] [Figure 3A] FIG. 3A is an illustration of steps in an exemplary process for manufacturing a catheter according to some embodiments of the subject invention.

[0038] [Figure 3B] FIG. 3B is an illustration of steps in an exemplary process for manufacturing a catheter according to some embodiments of the subject invention.

[0039] [Figure 3C] FIG. 3C is an illustration of steps in an exemplary process for manufacturing a catheter according to some embodiments of the subject invention.

[0040] [Figure 3D] FIG. 3D is an illustration of steps in an exemplary process for manufacturing a catheter according to some embodiments of the subject invention.

[0041] [Figure 3E] FIG. 3E is an illustration of steps in an exemplary process for manufacturing a catheter according to some embodiments of the subject invention.

[0042] [Figure 4A] FIG. 4A is an illustration of components at the distal end of another exemplary catheter according to some embodiments of the subject invention.

[0043] [Figure 4B] FIG. 4B is an illustration of components at the distal end of a catheter according to some embodiments of the subject invention.

[0044] [Figure 4C] FIG. 4C is an illustration of components at the distal end of a catheter according to some embodiments of the subject invention.

[0045] [Figure 5A] FIG. 5A is an illustration of components at the distal end of another catheter according to some embodiments of the subject invention.

[0046] [Figure 5B] FIG. 5B is a cross-sectional illustration of components at the distal end of a catheter according to some embodiments of the subject invention.

[0047] [Figure 6A] FIG. 6A is an illustration of components at the distal end of another catheter according to some embodiments of the subject invention.

[0048] [Figure 6B] FIG. 6B is an illustration of the components at the distal end of the catheter of FIG. 6A at a later stage of manufacture.

[0049] [Figure 6C] FIG. 6C is an illustration of the components at the distal end of the catheter of FIG. 6B at a later stage of manufacture.

[0050] [Figure 6D] FIG. 6D is a cross-sectional view of some of the components shown in FIG. 6C. DETAILED DESCRIPTION OF THE INVENTION

[0051] The following description is presented to enable any person skilled in the art to make and use the various embodiments disclosed herein. Descriptions of specific devices, techniques, and applications are provided only as examples. Various modifications of the examples described herein will be readily apparent to those skilled in the art, and the general principles described herein may be applied to other examples and applications without departing from the spirit and scope of the various embodiments. Accordingly, the various embodiments are not intended to be limited to the examples described and shown herein, but are to be accorded scope consistent with the claims.

[0052] The assignee herein has developed several low-profile shockwave electrodes that may be suitable for use in angioplasty and / or valvuloplasty procedures. For example, in U.S. Publication No. 2019 / 0150960, the assignee discloses a low-profile electrode assembly in which an outer electrode is formed by a conductive sheath and an inner electrode is formed by removing a portion of the insulated wire (e.g., cutting a hole in the insulation layer near the end of the wire) to expose a conductive portion of the insulated wire. The inner electrode is positioned a controlled distance from the side edge of the conductive sheath to enable reproducible arcing for a given current and voltage.

[0053] More recently, the assignee has developed several coplanar electrode assemblies for use in shockwave catheters. These designs provide novel configurations of electrode pairs (e.g., helical structures and tongue-and-groove designs) with each electrode on the same transverse plane to limit the overall thickness of the electrode assembly. These assemblies are particularly advantageous for generating shock waves in tight, difficult-to-pass lesions or completely blocked vessels. For example, in U.S. Pat. No. 9,993,292 and U.S. Publication No. 2018 / 0098779 (incorporated herein by reference), the assignee discloses forming electrode pairs from helically wound wire to generate shock waves at various circumferentially positioned gaps around a tubular structure. In U.S. Pat. No. 10,555,744 (also incorporated herein by reference), the assignee discloses a tongue and groove electrode assembly in which electrode pairs are formed from groove-shaped cutouts in a conductive sheath and coplanar tongue-shaped protrusions extending into the groove-shaped cutouts.

[0054] Described herein is a catheter incorporating a low-profile design element that enables intravascular lithotripsy (IVL) treatment of tougher, harder-to-cross calcific lesions and total coronary artery occlusions. The present invention is similar to existing IVL systems in that it may include an array of lithotripsy emitters (e.g., electrode pairs) on a catheter that is advanced into the patient's vasculature to deliver shock waves to the occlusion. However, the present invention further includes an inner member with a reduced distal segment to provide a low-profile distal end. One or more emitter assemblies can be mounted around the reduced distal segment.

[0055] In some embodiments, the catheters described herein include a low-profile cap or angioplasty balloon attached to the distal end of the catheter that can be positioned within a patient's vessel without collapsing. The low profile of the non-collapsing cap or balloon advantageously allows the catheter to advance even into tighter regions of the vessel, such as those that are partially or completely occluded. Once the balloon is positioned, the elastomeric material properties of the low-profile cap or balloon allow it to be inflated with a conductive fluid to increase the balloon's profile (i.e., to contact the occlusion and provide space within the balloon for the conductive fluid to bathe the electrodes).

[0056] In some embodiments, the catheters described herein include additional low-profile elements, such as coplanar electrodes, that further reduce the diameter of the distal end of the catheter. Additionally or alternatively, the catheter may provide electrical connections to the electrodes using a reinforcing wire sheath wrapped circumferentially around the catheter shaft. The reinforcing wire sheath provides the catheter with improved kink resistance, torsional transfer, and pushability for easier maneuvering of the device within the patient's vasculature.

[0057] FIG. 1 illustrates an exemplary catheter 10 for treating an intravascular obstruction according to one embodiment of the subject invention. The catheter 10 is advanced over a guidewire 20 carried within a guidewire sheath into an obstruction within a patient's vasculature, such as the stenotic lesion depicted in FIG. 1 . The distal end of the catheter 10 includes a shockwave generator 16 that produces shockwaves in multiple emitters (e.g., electrode pairs) to disrupt calcified lesions. As used herein, multiple emitters include electrode pairs having first and second electrodes separated by a gap, in which shockwaves are formed when current flows across the gap between the paired electrodes (i.e., when a voltage is applied across the first and second electrodes). The electrode pairs are arranged in a low-profile configuration that reduces the diameter of the distal end of the catheter 10 and enables treatment of stiff, difficult-to-traverse lesions. In some examples, the shockwave generator 16 includes one or more coplanar electrode pairs or one or more electrodes at least partially retracted within the catheter 10.

[0058] A thin, flexible cap or balloon 18 is sealably attached to the distal end of the catheter 10, forming an annular channel around the catheter shaft 12. The flexible cap or balloon 18 surrounds the shock wave generator 16 so that shock waves are produced in a closed system defined by the walls of the cap. The cap or balloon 18 is filled with a conductive fluid, such as saline. The conductive fluid allows acoustic shock waves to propagate from the electrode pair of the shock wave generator 16 through the walls of the cap or balloon 18 and then into the target lesion. In some embodiments, the conductive fluid may also contain an X-ray contrast agent to enable fluoroscopic visualization of the catheter 10 during IVL treatment. In some embodiments, the cap is rigid and not flexible. In some embodiments, when inflated with the conductive fluid, the diameter of the cap expands by up to 10-15%.

[0059] The catheter 10 also includes a proximal end or handle 22 that remains outside the patient's vasculature during treatment. The proximal end 22 includes an entry port for receiving the guidewire 20. The proximal end 22 also includes a fluid port 26 for receiving a conductive fluid for inflating and deflating the flexible cap 18 during treatment. An electrical connection port 24 is also located on the proximal end 22 to provide an electrical connection between the distal shockwave generator 16 and an external pulsed high-voltage source 28, such as the intravascular lithotripsy (IVL) generator shown in FIG. 1. In some embodiments, the handle is a Y-adapter. In some embodiments, a strain relief is provided at the handle junction.

[0060] The catheter 10 also includes a flexible shaft 12 extending from the proximal handle 22 to the catheter's distal end. The shaft 12 includes an inner member that provides various internal conduits connecting elements at the distal end with the catheter's handle 22. As described below, the inner member includes a guidewire lumen for receiving a guidewire 20. The inner member also defines several additional lumens extending longitudinally through the shaft 12. For example, one or more wire lumens can be included to carry conductive wires that electrically connect the pulsed voltage source 28 with the electrodes of the distal shockwave generator 16. In some embodiments, one or more fluid lumens (e.g., a fluid inlet lumen and a fluid outlet lumen) are provided within the inner member for carrying conductive fluid from the fluid port 26 into the cap or balloon 18. In some embodiments, the same lumen can be used to carry both wires and conductive fluid.

[0061] Optionally, the flexible shaft 12 includes a reinforcing wire sheath wrapped circumferentially around the inner member. The reinforcing wire sheath provides mechanical support to the flexible shaft 12 to facilitate twisting, pushing, and steering of the catheter 10 through the patient's vasculature. In some embodiments, a tubular outer jacket or plastic liner covers the guidewire sheath and reinforcing wire sheath, providing a barrier between the active elements of the catheter 10 and the in situ environment. In some embodiments, additional proximal reinforcement can be applied (using additional plastic, metal, or other potentially enhancing components) for added pushability and torsional transferability.

[0062] 2A is an illustration of components at the distal end of a catheter (e.g., catheter 10) according to some embodiments of the subject invention. The catheter comprises an inner member 202. The inner member 202 comprises a base segment 202a and a low-profile extension segment 202b. Both the base segment 202a and the extension segment 202b are cylindrical, with the diameter of the extension segment 202b being smaller than the diameter of the base segment 202a, thus creating a low-profile distal end.

[0063] The thin extension segment 202b includes a lumen for accommodating a guidewire (e.g., guidewire 20). The base segment 202a carries two wires 206 and 208. Wires 206 and 208 are insulated wires (e.g., polyimide-insulated copper wires) with conductive distal ends. In some embodiments, the insulation layer at the distal ends of the wires is cut to expose the inner conductive cores of the wires. The two wires, together with the conductive sheaths, form two electrode pairs for generating shock waves, as described herein.

[0064] The location, size, and shape of the removed portion of the insulation can be varied to control the location, direction, and / or magnitude of the shock wave. In some embodiments, flat wire, rather than round wire, is used to further reduce the cross-sectional profile of the electrode assembly.

[0065] Inner member 202 further provides an inlet for the conductive fluid. In the depicted example of FIG. 2A , the base segment houses tubing 210 as an inlet flush port for introducing the conductive fluid into the distal end of the catheter. Tubing 210 can be polyimide tubing. In the depicted example, a distal portion of tubing 210 protrudes outward from the base segment. In some embodiments, a mandrel can be placed within the lumen in place of tubing 210 as an inlet port.

[0066] The inner member 202 also provides an outlet for the conductive fluid. In the depicted example of Figure 2A, the base segment includes an outlet lumen 204 as an outlet flush port for conveying the conductive fluid away from the distal end of the catheter. The lumen 204 has two functions: in addition to being an outlet flush port, the lumen 204 also accommodates the wires 206 of the electrode assembly, thereby conserving space and further reducing the profile of the catheter at the distal end.

[0067] A tubular reinforcing wire sheath 220 formed from at least one reinforcing wire material, such as metal or plastic, surrounds the inner member 202. The wire material can be braided, coiled, or both, at various pitches. The reinforcing wire sheath 220 can also provide advantageous mechanical properties to the catheter shaft. For example, the material composition of the reinforcing wire sheath 220 can provide increased torsional transmission, pushability, or enhanced stiffness to the catheter shaft, facilitating steering of the catheter through the patient's vasculature. The material of the wire sheath 220 can be radiopaque to facilitate visual tracking of the catheter.

[0068] The reinforcing sheath 220 can be laminated with a plastic liner 222. The plastic liner can be of various materials or hardnesses to allow for improved mechanical properties such as pushability and torsional transmission. The sheath 220 and / or the plastic liner 222 can be flattened to reduce the catheter's profile and allow it to fit more easily into a tightly occluded vessel. As shown in FIG. 2B, the reinforcing sheath 220 and the plastic liner 222 do not extend to the distal end of the base segment 202a, thus leaving the distal segment of the base segment 202a exposed.

[0069] 2B, conductive sheath 212 is positioned around wires 206 and 208 and flush port tubing 210. The outer diameter of conductive sheath 212 is smaller than that of base segment 202a so that proximal edge 212b of the conductive sheath can be angled against the distal surface of base segment 202a. In some embodiments, adhesive or thermally bonded plastic can be used to hold the wires, conductive sheath, and flush tubing 210 in place. In some embodiments, tubing 210 is optional.

[0070] The two wires 206 and 208, together with the conductive sheath 212, form an electrode assembly. The electrode assembly includes two electrode pairs as described in the assignee's prior application, U.S. Publication No. 2019 / 0150960. For example, a first electrode pair is formed by a conductive portion of the wire 206 (i.e., the first electrode) and a portion of the distal ring edge of the conductive sheath 212 (i.e., the second electrode). A second electrode pair is formed by a portion of the distal ring edge of the conductive sheath 212 (i.e., the third electrode) and a conductive portion of the wire 206 (i.e., the fourth electrode).

[0071] The distal end of each wire and the conductive sheath are spaced apart to define a gap between the two electrodes of the electrode pair. The gap spacing can be controlled to generate a reproducible electric arc in the conductive fluid between the electrodes. The electrode spacing can be modified to produce a shock wave of a desired magnitude for a given voltage and current output from the pulsed voltage source. The distal ends of wires 206 and 208 may or may not protrude beyond the distal edge of the conductive sheath. Wires 206 and 208 may shorten over time, thus changing the location of their distal ends relative to the conductive sheath.

[0072] The electrode assembly is formed around the thin extension segment 202b of the inner member, thus having a low-profile configuration to reduce the diameter of the distal end of the catheter. The first and second electrode pairs are located approximately 120 degrees circumferentially around the inner member. The electrodes of each pair are spaced to define a gap through which electrical current can flow to produce shock waves in the conductive fluid inside the flexible cap.

[0073] The relative positioning of the conductive sheath 212 at the distal end of the base segment 202a can be configured to control the flow of conductive fluid. In the depicted example, the conductive sheath does not completely block the exit lumen 204. Rather, at least a portion of the exit lumen (i.e., the gap 205) is unblocked outside the outer diameter of the conductive sheath 212. Thus, conductive fluid can be introduced into the conductive sheath 212 via the inlet tubing 210, flow out of the conductive sheath 212 at its distal end, then flow around the outside of the conductive sheath 212, and finally exit via the exit lumen 204 (e.g., via the gap 205). In this manner, the inlet tubing 210 and the outlet tubing 204 are positioned to maximize fluid flow across the electrode pairs, such that fluid flowed through the distal end of the catheter via the inlet and outlet ports flows across at least one of the electrode pairs.

[0074] The return path for the conductive fluid outside / around the conductive sheath 212 can be maintained in several ways. In some embodiments, the conductive sheath 212 can be flattened or oval to allow a larger portion of the exit lumen 204 (e.g., fissure 205) to be accessible outside the conductive sheath 212. In some embodiments, the conductive sheath 212 can be offset from the central axis of the base segment 202a. In some embodiments, the portion of the exit lumen 204 inside the conductive sheath 212 can be sealed off so that only the conductive fluid enters via the inlet tubing 210 and exits via the outer portion of the exit lumen 204 (e.g., fissure 205).

[0075] In an alternative embodiment, the conductive sheath 212 can be positioned at the distal end of the proximal segment 202a such that the exit lumen 204 is completely within the conductive sheath. Thus, the conductive fluid exits via the exit lumen 204 within the conductive sheath 212. In yet other embodiments, the exit lumen 204 is partially inside and partially outside the conductive sheath 212 such that the conductive fluid can exit via the exit lumen 204 either inside or outside the conductive sheath.

[0076] In some embodiments, the conductive sheath 212 is formed at least in part from a radiopaque material such as platinum, iridium, or stainless steel to effect lithotripsy and allow fluoroscopic visualization of the catheter during use.

[0077] 2C and 2D, the distal end of the catheter includes a non-collapsible cap 230. The non-collapsible cap fits over the distal end of the catheter, closing the flushing pathway and encapsulating the emitter assembly. As depicted, the proximal edge of the cap is bonded to the distal edge of the plastic liner 222, forming a closed annular channel around the distal end of the catheter. When a conductive fluid is introduced into the distal end of the catheter, the conductive fluid can flow through the emitter assembly and exit via the exit port. The space between the inner member and the plastic liner can be sealed off from the distal portion of the catheter to prevent the conductive fluid from contacting the wire sheath 222.

[0078] Additionally, the distal end of the cap can be bonded to the distal end of the extension segment 202b to form a closed space and prevent the conductive fluid from leaking at the distal end. The lumen defined by the extension segment 202b is not blocked by the cap to allow a guidewire to pass through. The cap 230 can be thermally or adhesively bonded in place.

[0079] Cap 230 is a "non-folding" cap because it does not contain any material that must be folded before insertion into the cardiovascular system. Instead, the cap comprises a piece of extruded tubing (e.g., extruded polymer tubing) that is stretched and reshaped to the desired shape and then joined to the distal end of the catheter. Such a cap can be expanded a relatively small amount (e.g., up to 10-15%) sufficient to immerse the electrodes in a conductive fluid before generating shock waves at the electrodes to treat the occlusion. To maintain its low-profile shape, the cap is preferably formed from a material (e.g., a semi-compliant polymer) such that the cap can be minimally inflated during treatment of the occlusion and then returned to its low-profile state when deflated after treatment. Alternatively, a low-profile balloon can be used. Additional details of low-profile caps and balloons can be found in U.S. Application No. 17 / 021,905, incorporated herein by reference.

[0080] Thus, cap 230 maintains a very low profile in both the expanded and unexpanded states. In some embodiments, the outer diameter of cap 230 is less than 1.5 mm. The extremely low profile of cap 230 allows the distal end of the catheter to access tightly occluded areas of the vessel. When the cap is inflated with a conductive fluid, it expands, providing additional space between the inner surface of the cap and the electrode pair. In some examples, the outer diameter of inner member extension segment 202b is approximately 0.019 to 0.02 inches, and the inner diameter of the inflated cap is less than 1.5 mm, providing space between the inner member and the inner surface of the cap. The space ensures that the electrode pair is immersed in the conductive fluid during shock wave generation, and that the inner surface of the cap is sufficiently far from the electrode pair so that the cap material is not damaged by the shock waves. In some embodiments, the diameter of the cap is 0.75 to 1.5 mm.

[0081] In some embodiments, the distal end of the catheter can have an atraumatic profile. The atraumatic profile can be the addition of a soft atraumatic tip (not depicted) via adhesive or thermal means. In some embodiments, the soft tip tapers toward the distal tip of the catheter. The soft tip can be formed from a polymer or any other suitable biocompatible material. In preferred embodiments, the tip is formed, at least in part, from a radiopaque material such as platinum, iridium, or stainless steel to allow fluoroscopic visualization of the catheter during use. Providing a soft tip can facilitate contact with and penetration into rigid lesions within the vessel while preventing physical damage to the vessel wall.

[0082] The operation of the catheter will now be described with reference to FIGS. 1-2C. The catheter 10 can be used to treat occlusions within a vessel, such as stenotic lesions, calcified sections of an artery, or some other occlusion within a blood vessel. Referring to FIG. 1, in operation, a physician advances a guidewire 20 from an entry site on a patient (e.g., an artery in the groin area of ​​a leg) to a target area of ​​the vessel (e.g., an area having an occlusion that needs to be disrupted). The catheter 10 is then advanced over the guidewire 20 to the target area of ​​the vessel. In some examples, the flexible cap 18 sealed at the distal end is a non-collapsible cap with a low profile so that the cap can be freely advanced through the vessel. During the positioning phase of treatment, a guide catheter or wire sheath can be used to aid in the entry and navigation of the catheter 10 within the vessel. The wire sheath provides tubular linear support to the catheter shaft 12 during pushing, traversing, and placement of the catheter 10. The in situ location of the distal end of catheter 10 may be determined by x-ray imaging and / or fluoroscopy.

[0083] The distal end of the catheter 10 is advanced as far as possible into the rigid lesion. The flexible cap 18 is then minimally inflated with a conductive fluid (e.g., saline and / or saline mixed with an imaging contrast agent) introduced via the fluid port 26, allowing the conductive fluid to expand the cap so that its outer surface contacts the target lesion. The cap is inflated to an IVL pressure of approximately 1 atmosphere to approximately 6 atmospheres. The diameter of the flexible cap in the inflated state may exceed the diameter of the flexible cap in the deflated state by up to 10-15%. However, in some instances, the diameter of the cap in the inflated state exceeds the diameter of the cap in the deflated state by less than 10%.

[0084] A voltage pulse is then applied across one or more electrode pairs (i.e., the emitters of the shockwave generator 16) by the pulsed high-voltage source 28. Referring to FIG. 2B, in operation, a physician may trigger the power supply, which will simultaneously supply current across wires 206 and 208. In such an example, current will flow from the voltage source, down wire 206, across a first gap between the insulation-removed distal portion of wire 206 and the edge of conductive sheath 212, generating a plasma arc that generates a shockwave at the first electrode pair. Current will also flow across conductive sheath 212 and across a second gap between the edge of conductive sheath 212 and the insulation-removed distal portion of wire 208, generating another plasma arc that generates a shockwave at the second electrode pair. The current return path is along wire 208 to the negative lead or ground.

[0085] Each pulse first ionizes the conductive fluid within the thin cap 230 (FIG. 2C), generating a small gas bubble at the distal end of the catheter. Fluid can be continuously flushed through the cap via the inlet and outlet lumens during treatment at a constant rate to clear bubbles and debris from the electrodes. The fluid flow rate can be controlled throughout the treatment but is generally within the range of about 1 ml / min to about 3 ml / min. At some point, a plasma arc forms across the electrode pair, creating a low-impedance path along which current can flow freely. Heat from the plasma arc heats the conductive fluid, generating a rapidly expanding vapor bubble. The expanding vapor bubble generates a shock wave that is conducted through the fluid, through the wall of the thin cap, and into the occlusion, where the energy shatters the hardened lesion.

[0086] For the treatment of intravascular occlusions, the voltage pulses applied by the voltage pulse generator 28 are typically in the range of about 2,000 volts to about 3,000 volts, preferably 2,300 to 3,000 volts. The repetition rate or frequency of the applied voltage pulses can be about 1 Hz to about 10 Hz. However, the preferred voltage and repetition rate can vary depending on, for example, the size of the lesion, the degree of calcification, the size of the vessel, the patient's demographics, or the stage of treatment. For example, a physician may start with low-energy shock waves and increase the energy as needed during the procedure. The magnitude of the shock waves can be controlled by controlling the voltage, current, duration, and repetition rate of the pulsed voltage from the pulsed voltage source 28. Further information on the physics of shock wave generation and their control can be found in U.S. Patent Nos. 8,956,371, 8,728,091, 9,522,012, and 10,226,265, each of which is incorporated by reference.

[0087] During an IVL treatment, one or more cycles of shock waves can be applied to create a more compliant vessel. For example, once the stenosis has been sufficiently softened by the first cycle of shock waves, the thin cap 230 can be contracted and the distal end of the catheter can be advanced further into the occlusion. The flexible cap 230 can then be re-inflated and another cycle of shock waves can be applied. Further advancement of the cap 230 can be attempted after the completion of the successive cycles.

[0088] In some embodiments, the catheter can be used to treat a total occlusion in a blood vessel, such as a coronary total occlusion (CTO). When treating a total occlusion, a guidewire is advanced at least partially into the stenotic lesion. The catheter is then advanced through the patient's vasculature over the guidewire and at least partially into the lesion. A low-profile cap is then inflated with a conductive fluid until the cap gently contacts the lesion. Voltage pulses are then supplied by a pulsed voltage source to an electrode pair at the tip of the catheter, generating shock waves that disrupt (or relax) the lesion. The guidewire and catheter can then be advanced further into the lesion, and shockwave treatment can be repeated until the total occlusion is cleared or until the diameter of the blood vessel is larger, allowing for the placement of a more conventional angioplasty device.

[0089] In some embodiments, the catheter can be used in small blood vessels that are partially obstructed by a stenotic lesion. In this situation, a guidewire can be advanced further into the lesion, and in some cases, through the entire lesion. After positioning the guidewire, the catheter is advanced through the lesion in stages. At each stage, a low-profile cap is inflated and shock waves are generated to shatter the obstruction and increase the diameter of the vessel. As described above, once the vessel diameter is large enough, a larger-diameter catheter can be advanced through the vessel to complete the treatment.

[0090] The progress of the procedure may be monitored by X-ray and / or fluoroscopy. The shockwave cycle can be repeated until the blockage is cleared or a channel is formed within the lesion with a diameter sufficient to receive a second treatment device with a larger profile. For example, the enlarged channel can receive a more conventional angioplasty balloon or a different catheter with a differently directed shockwave source. Catheters of this type are described in the above-cited U.S. Pat. No. 8,747,416 and U.S. Publication No. 2019 / 0150960. Once the lesion is sufficiently treated, the flexible cap 18 can be further inflated and then deflated, and the catheter 10 and guidewire 20 can be withdrawn from the patient.

[0091] 3A-E illustrate steps in an exemplary process for manufacturing a catheter according to some embodiments of the subject invention. FIG. 3A depicts a tubular inner member 202 with three lumens (i.e., a three-lumen configuration). In some embodiments, polyimide or etched PTFE tubing can be used in one or more of the lumens. For example, lumen 201 (i.e., the lumen carrying the fluid inlet port) and lumen 204 (i.e., the lumen serving as the fluid outlet) can each include a polyimide lining to prevent any crosstalk between the inflow and outflow of conductive fluid within the catheter.

[0092] Referring to FIG. 3B, a tubular reinforcing wire sheath 220 is applied over the inner member. In the depicted example, the wire sheath 220 comprises a reinforced braided wire structure threaded over the inner member. The proximal and distal segments of the inner member are not braided thereon. The wire material can be braided, coiled, or both, in various pitches and sizes. The reinforcing wire sheath 230 can also provide advantageous mechanical properties to the catheter shaft. For example, the material composition of the reinforcing wire sheath 220 can provide increased torsional transmission, pushability, or enhanced stiffness to the catheter shaft, facilitating manipulation of the catheter through the patient's vasculature.

[0093] 3C, reinforcing sheath 220 can be surrounded with a plastic liner 222 to create an assembly. The plastic liner can be of various materials or hardnesses to allow for improved mechanical properties such as pushability and torsional transfer. As shown in FIG. 3C, reinforcing sheath 220 and plastic liner 222 do not extend to the distal end of inner member 202.

[0094] Referring to Figure 3D, the distal end of the inner member is trimmed to form a base segment 202a and an extension segment 202b. As shown, in extension segment 202b, only one lumen remains for carrying a guidewire. The reduced outer diameter of the distal segment of the inner member is used to house an emitter assembly such as that shown in Figures 2A-C.

[0095] 3E, the two wires of the emitter assembly are loaded along lumens 201 and 204. As discussed above, each of the two lumens may include a polyimide lining to insulate the lumen and prevent any fluid connection between the two lumens (which could cause a short circuit). In some embodiments, the inner member may include additional lumens within base segment 202a to accommodate additional emitter assemblies. Additionally or alternatively, multiple wires (e.g., from multiple emitter assemblies) can be housed within a single lumen within the inner member.

[0096] After the wire is loaded, tubing (e.g., tubing 210 in FIG. 2A) is inserted into lumen 201 as an inlet flush port for introducing conductive fluid into the distal end of the catheter. Lumen 201 is sealed with an adhesive or thermally bonded, as shown in FIG. 2A. Alternatively, a mandrel can be placed into lumen 201 in place of the tubing and then sealed with an adhesive or thermally bonded.

[0097] In some examples, each wire is a polyimide-insulated copper wire having a diameter of about 0.003 inches to about 0.007 inches. The wires are flattened to reduce the profile of the catheter, and the flattened wires may have a cross-section that is about 0.003 inches thick and about 0.010 inches wide. Furthermore, the lumens within the inner member may have any desired shape. The location, size, and shape of any of the lumens can be modified to reduce the profile of the catheter or to provide some other benefit. Furthermore, various lumens may be combined (e.g., by providing two or more insulated wires within the same lumen) or eliminated without departing from the scope of the present invention.

[0098] 4A-C illustrate the distal end of another exemplary catheter according to some embodiments of the subject invention, which includes an oval conductive sheath to achieve a low profile and / or to provide a larger portion of the fluid exit ports to be accessible outside the conductive sheath, as described below.

[0099] Referring to Figure 4A, the catheter includes an inner member 402 including a base segment 402a and an extension segment 402b. The inner member can be manufactured in a similar process and operate in a similar manner as described above with reference to Figures 2A-3E. The extension segment 402b carries a mandrel 420 that serves as a guidewire lumen.

[0100] Referring to FIG. 4B, an emitter assembly comprising two wires and a conductive sheath 412 is mounted around a low-profile extension segment 402b of the inner member. In the depicted example, the two wires are spaced approximately 150 degrees circumferentially around the extension segment 402b to achieve a low profile and generate shock waves more uniformly around the catheter. Additionally, the conductive sheath 412 is oval or flattened to achieve a low profile. Additionally, the oval shape provides a larger portion of the fluid exit port 404 to be accessible outside the conductive sheath, allowing the conductive fluid to flow over the conductive sheath.

[0101] Referring to Figure 4C, a low-profile cap is fitted over the distal end to close the flush passage and encapsulate the emitter assembly. The cap can be adhesively attached or thermally bonded to the inner member. As explained above, most distal tips are given an atraumatic profile by thermal means or by the addition of a soft atraumatic tip with an adhesive.

[0102] 2A-4C, the inner member comprises three lumens: a first lumen (e.g., 201 in FIG. 3D) that both accommodates a first wire 208 and serves as an inlet flush port; a second lumen (e.g., 204 in FIG. 3D) that both accommodates a second wire 206 and serves as an outlet flush port; and a third lumen that accommodates a guidewire. However, it should be understood that the design of the inner member is not so limited. For example, the inner member could include additional lumens, whereby a separate lumen could be used to accommodate a wire and serve as a flush port.

[0103] For example, the inner member can include four lumens: a first lumen for accommodating a wire; a second lumen for serving as a flush port; a third lumen for both accommodating other wires and serving as another flush port; and a fourth lumen for accommodating a guidewire. As another example, the inner member can include five lumens: two lumens for accommodating two wires; two lumens for accommodating two flush ports; and a fifth lumen for accommodating a guidewire. An exemplary inner member having five lumens is depicted in Figures 5A-5B, as described in detail below.

[0104] Additionally, in the embodiments depicted in FIGS. 2A-4C, there are two configurations for the lumen that both accommodates the wire and serves as a flush port. One configuration is illustrated by lumen 204, where the distal end of the lumen is not sealed, with the entire distal opening serving as the flush port. The second configuration is illustrated by lumen 201 (FIGS. 3D and 2A), where the distal end of the lumen is sealed, leaving only a relatively small opening that serves as the flush port. In the second configuration, optional tubing 210 can be attached to the small opening to control the precise location of the port. While the embodiment depicted in FIGS. 2A-4C shows an inner member having a lumen in the first configuration and a lumen in the second configuration, it should be understood that the design is not so limited. For example, the inner member could have two lumens, one in each of the first configuration or both in the second configuration. It should further be understood that the choice of configuration can affect the amount and distribution of shock waves.

[0105] 2A-4C, the extension segments (e.g., 202b) are integral parts of the inner member and can be formed by trimming the distal end of the inner member, as shown in Figures 3C-D. However, the low-profile segments can be constructed by other means, as described below.

[0106] 5A-5B illustrate components of another exemplary catheter according to some embodiments of the subject invention. In Figures 5A-B, a separate guidewire member 520 is attached to the distal end of inner member 502. Specifically, the proximal end of guidewire member 520 can be attached (e.g., glued) to the distal end of the inner member. A lumen 521 within guidewire member 520 aligns with the central lumen of inner member 502, and a guidewire can extend through the inner member and the guidewire member.

[0107] In some embodiments, to attach guidewire member 520 to inner member 502, a small portion (e.g., 2-3 mm) of the proximal end of the guidewire member is inserted into the central lumen of the inner member. Heat can be applied to melt material at the insertion site and bond the guidewire member to the inner member. In some embodiments, a mandrel can be placed within the lumen of the inner member and / or guidewire member during heating to prevent the lumen from being distorted by the heat.

[0108] 5A and 5B, the outer surface of guidewire member 520 includes grooves 520a and 520b. Because wires 506 and 508 are flexible, distal portions of the wires can be placed within the grooves to further secure the wires (e.g., via glue) and reduce the distal profile of the catheter. A conductive sheath 512 is wrapped circumferentially around the wires and guidewire member. Lumens 504 and 505 define two independent flush ports.

[0109] Inner member 502 includes five lumens (two for accommodating two wires, two for serving as flush ports, and one for accommodating a guidewire), although it may alternatively include three or four lumens, as described above.

[0110] 6A-6D illustrate components of another exemplary catheter according to one embodiment of the subject invention. This embodiment is similar to the embodiment of FIG. 5, with some modifications as described below.

[0111] In this embodiment, the inner member 620 is formed from a single extrusion with four channels or flutes 640, 642 (two are visible in FIG. 6A) and a guidewire lumen 621. The distal end of the member 620 is narrowed to provide a reduced diameter region at the distal end. The more proximal portion of the inner member has a larger diameter and contains four channels. One polyimide tube 644, 646 (four total) is aligned with each of the four channels. Two of the tubes are used to carry wires. One of the tubes provides an inlet for supplying conductive fluid to the distal tip of the catheter, and the fourth tube provides a return path for the fluid. The fourth tube can be connected to a suction source.

[0112] As seen in FIG. 6B, a jacket 648 surrounds the polyimide tube. A cylindrical insulating sleeve 650 surrounds a portion of the inner member and can extend to a distal opening within the polyimide tube. The sleeve 650 can be formed from two pieces, including a constant diameter distal portion and a tapered proximal portion. Alternatively, the sleeve can be formed from one piece as shown. FIG. 6B shows two wires 606 and 608, each extending out of the tube and along a portion of the insulating sleeve.

[0113] A more complete assembly is seen in Figure 6C and includes a cylindrical conductive sheath 612 that surrounds the tips of wires 606 and 608 and defines two electrode pairs. When a voltage is applied to the proximal ends of wires 606 and 608, current travels along wire 606, jumps the gap between the insulation-displaced distal ends of the wires, traverses to the sheath, then travels around the sheath and jumps the gap to the insulation-displaced distal end of wire 608, where it will return to ground. Shock waves are generated in both gaps, as discussed in detail above.

[0114] As seen in Figure 6C, a flexible cap 630 is mounted on the distal end of the catheter. The structure of the minimally expanding cap is discussed above. As in other embodiments, the more proximal portion of the catheter can include a sheath 654 defined by a reinforcing wire braid.

[0115] 6D is a cross-section showing inner member 620 defining guidewire sheath 621. Wires 606 and 608 reside within their own tubes. As described above, tube 604 provides an inlet for the conductive fluid, and tube 605 can provide a return path for removing the fluid. In this embodiment, the wires and fluid inlet and outlet are separated within separate channels along the catheter.

[0116] It should be noted that the elements and features of the exemplary catheters illustrated herein may be rearranged, recombined, or modified without departing from the present invention. Furthermore, the subject invention is intended to include catheters having various electrode configurations. For example, the shockwave generator of the exemplary catheter may include two tongue-and-groove electrode pairs, two point-and-circle electrode pairs, or two electrode pairs formed from a distal conductive portion of a wire and a conductive sheath, or any other desired configuration. Furthermore, the placement and spacing of the electrode pairs may be modified without departing from the subject invention. For example, the electrode pairs may be circumferentially spaced around the catheter in consistent increments, e.g., 180 degrees apart, 90 degrees apart, or 60 degrees apart, to generate shockwaves more uniformly circumferentially around the catheter. In some examples, the shockwave generator includes electrode pairs positioned in various groupings spaced longitudinally along the catheter. For example, the shock wave generator may include multiple electrode pairs defined by multiple conductive sheaths spaced longitudinally along the catheter. In such an example, a pulsed voltage source may be controlled to selectively generate high-voltage pulses in either the proximal or distal electrode pairs, e.g., by applying voltage pulses across different sets of wires or other conductors leading to each pair. For example, during the first phase of treatment (i.e., during the initial treatment of a rigid or completely occluding lesion), only the distal electrode pair is activated to generate shock waves. After the rigid lesion is corrected, allowing a more proximal portion of the cap 18 to cross the lesion, the cap is re-inflated, and the more proximal electrode pair is activated to generate the more proximal shock waves.

[0117] It should also be understood that the positions of the wires and fluid channels can be varied from the configuration shown. For example, considering FIG. 6D, the locations of wire 608 and channel 605 can be swapped. Indeed, any two tubes can contain wires, and any two channels can be used for fluid exchange. Additionally, the angular spacing of the elements can be adjusted to improve performance.

[0118] It should be understood that the foregoing is merely illustrative of the principles of the present invention, and that various modifications, alterations, and combinations may be made by those skilled in the art without departing from the scope and spirit of the present invention. Any of the various shockwave catheter variations disclosed herein may include features described with any other shockwave catheter or combination of shockwave catheters herein. Furthermore, any of the methods may be used with any of the disclosed shockwave devices. Accordingly, the present invention is not intended to be limited, except as by the appended claims.

Claims

1. 1. A catheter for treating an occlusion in a blood vessel, the catheter comprising: A tubular inner member, the tubular inner member comprising: a base segment, the base segment comprising: a first lumen; a second lumen defining a fluid exit port; and a base segment defining a an extension segment distal to the base segment, the extension segment having a smaller cross section than the base segment; an inner tubular member comprising:

1. An emitter assembly for emitting a shock wave, said emitter assembly comprising: a first insulated wire extending through the second lumen; a second insulated wire; a conductive sheath wrapped circumferentially around the first insulated wire, the second insulated wire, and the extension segment; an emitter assembly comprising: a cap or balloon surrounding the emitter assembly; Equipped with the cap or balloon is fillable with a conductive fluid; The emitter assembly includes: a first electrode pair comprising the conductive sheath and a conductive portion of the first insulated wire spaced from the conductive sheath; a second electrode pair comprising the conductive sheath and a conductive portion of the second insulated wire spaced from the conductive sheath; A catheter comprising:

2. The catheter of claim 1 , wherein the extension segment is configured to receive a guidewire.

3. 2. The catheter of claim 1, wherein the extension segment is connected to a third lumen in the base segment, the extension segment being formed by removing walls of the first lumen and the second lumen at the distal end of the inner member.

4. A catheter as described in claim 1, wherein the first lumen defines a fluid inlet port, and the fluid inlet port comprises tubing extending from the first lumen.

5. The catheter of claim 4 , wherein the second insulated wire extends through the first lumen.

6. The catheter of claim 5 , wherein a distal end of the first lumen is sealed to expose only a portion of the second insulated wire and a portion of the tubing.

7. The catheter of claim 1 , wherein the conductive fluid is configured to flow around the conductive sheath and exit via a space between an outside of the conductive sheath and a wall of the second lumen.

8. The catheter of claim 1 , wherein the first electrode pair and the second electrode pair are positioned approximately 180 degrees circumferentially apart around the conductive sheath.

9. The catheter of claim 1 , wherein the proximal ends of the first insulated wire and the second insulated wire are connectable to a pulsed voltage source.

10. The catheter of claim 1 , further comprising a reinforcing wire sheath wrapped circumferentially around the inner member sheath.

11. The catheter of claim 10 , wherein the reinforcing wire sheath comprises at least one braided or coiled metal wire encapsulated in a polymer.

12. 10. The catheter of claim 1, wherein the cap or balloon is flexible and can be expanded by inflation with the conductive fluid, and the maximum inflated diameter of the flexible cap or balloon is no more than 15% greater than the contracted diameter of the flexible cap.

13. The catheter of claim 1 , wherein the cap or balloon is made from a material that has elastomeric properties so that after being inflated, the cap or balloon returns to a low-profile configuration when the cap or balloon is deflated.

14. The catheter of claim 1 , wherein the cap comprises an extruded polymer tube.

15. 10. The catheter of claim 1, wherein a balloon is attached to the distal end of the catheter, and when the balloon is in a deflated state, the surface area of ​​the balloon is small enough that the balloon does not collapse when the catheter is advanced into a blood vessel.

16. The catheter of claim 1 , wherein the first insulated wire and the second insulated wire are flattened.

17. The catheter of claim 1 , wherein the conductive sheath is oval.

18. The catheter of claim 1 , further comprising a soft tip that tapers toward the distal end of the catheter.

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