Intravascular lithotripsy balloon perfusion catheter

Abstract

The present disclosure provides a balloon catheter for treating a stenosis in a body cavity, the balloon catheter comprising at least one shock wave generator located within at least one balloon and at least one channel that allows blood to flow through the body cavity past the balloon while the balloon is inflated. The at least one channel acts as a bypass around the inflated balloon(s) of the catheter so that blood flow through the body cavity is not generally completely blocked during shock wave treatment.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 451,115, entitled "INTRAVASCULAR LITHOTRIPSY BALLOON PERFUSION CATHETERS," filed March 9, 2023, and U.S. Patent Application No. 18 / 593,691, filed March 1, 2024, the entire contents of which are incorporated herein by reference.

[0002] Field of the Disclosure The present disclosure relates generally to the field of medical devices and methods, and more particularly to a shockwave catheter device for treating calcified lesions in body cavities, such as calcified lesions and obstructions in the vasculature, and kidney stones in the urinary system. [Background technology]

[0003] background Various catheters have been developed for treating calcified lesions, such as those in the vasculature associated with arterial disease. For example, treatment systems for percutaneous coronary intervention or peripheral angioplasty use angioplasty balloons to widen the calcified lesion and restore normal blood flow within the vessel. In these types of procedures, a catheter carrying the balloon is advanced through the vasculature along a guidewire until the balloon is aligned with the calcified plaque. The balloon is then pressurized (usually to greater than 10 atmospheres), expanding the balloon within the vessel and pushing the calcified plaque back into the vessel wall, widening the occluded area of ​​the vasculature.

[0004] When relying on angioplasty balloons to widen occluded areas of the vasculature, one concern is the temporary blockage of blood flow while the balloon is inflated. Lack of blood flow within a vessel (e.g., ischemia) can lead to hypoxia and microvascular dysfunction, which can lead to heart attack, organ failure, or stroke. To prevent ischemia, the treatment period during which the angioplasty balloon is inflated can be shortened, such as by limiting the inflation period to 60 seconds. Treatment protocols can involve alternating periods of balloon inflation with periods of non-inflated balloons during the procedure, allowing blood to flow intermittently through the device. However, limiting treatment to only short and / or intermittent periods can extend the total treatment period and introduce other problems, such as increased wear on device components from repeatedly inflating and deflating the balloon multiple times within a single procedure.

[0005] While a limited treatment period may be effective in some applications, it may not be effective for certain treatment protocols. For example, when treating calcification in the ventricular stenotic valve leaflets (balloon valvuloplasty), the heart valve orifice cannot be blocked by the balloon for more than approximately 10 to 15 seconds. During balloon valvuloplasty, physicians typically remove the catheter after a single cycle of inflating the balloon, do not repeat the inflation process, and optionally place a prosthetic valve in place of the heart valve if cardiac function remains insufficient. Insufficient pretreatment of calcification before prosthesis placement can lead to paravalvular leakage and uneven opening or deployment of the prosthetic valve. Therefore, a limited treatment period and / or intermittent inflation periods during balloon valvuloplasty may not be sufficient to treat calcification in the ventricle.

[0006] More recently, intravascular lithotripsy (IVL) techniques and procedures have been developed, which are interventional procedures for modifying calcified plaque in diseased arteries. The mechanism of plaque modification relies on the use of a catheter with one or more acoustic shock wave sources located within a fluid that can generate acoustic shock waves that modify the calcified plaque. IVL devices vary in design with respect to the energy source used to generate the acoustic shock waves; two exemplary energy sources are electrohydraulic generation and laser generation.

[0007] For electrohydraulic generation of acoustic shock waves, a conductive solution (e.g., saline) can be contained within an enclosure surrounding the electrode or can be flowed through a tube surrounding the electrode. Modification of calcified plaque is achieved by generating acoustic shock waves within the catheter via an electrical discharge across the electrode. Energy from this discharge enters the surrounding fluid faster than the speed of sound, generating an acoustic shock wave. In addition, the energy generates one or more rapidly expanding and collapsing vapor bubbles, which generate secondary shock waves. The shock waves propagate radially outward, modifying the calcified plaque within the blood vessel. For laser generation of acoustic shock waves, a laser pulse is transmitted into the fluid within the catheter and absorbed by the fluid. This absorption process rapidly heats and vaporizes the fluid, generating rapidly expanding and collapsing vapor bubbles and acoustic shock waves that propagate outward and modify the calcified plaque. The intensity of the acoustic shock waves is higher when a fluid is selected that exhibits strong absorption at the laser wavelength used. These examples of IVL devices are not intended to be a comprehensive list of potential energy sources for generating IVL shock waves.

[0008] The IVL process can be considered different from standard atherectomy procedures in that it breaks up calcium but does not liberate it from the tissue. Therefore, generally speaking, IVL should not require suction or embolism prevention. Furthermore, due to the compliance of normal blood vessels and non-calcified plaque, the shock waves generated by IVL do not modify normal vascular tissue or non-calcified plaque. Furthermore, IVL does not carry the same risk of perforation, dissection, or other damage to the vasculature as atherectomy procedures or angioplasty procedures using cutting or scoring balloons.

[0009] More specifically, catheters for delivering IVL therapy have been developed that include a pair of electrodes for electrohydraulic shock waves generated inside an angioplasty balloon. Shock wave devices can be particularly effective in treating calcified plaque lesions because the acoustic pressure from the shock waves can spall and destroy lesions near the angioplasty balloon without damaging surrounding tissue. In these devices, the catheter is positioned proximal to and / or advanced over a guidewire through the patient's vasculature until aligned with the calcified plaque lesion within a body cavity. The balloon is then inflated (using a relatively low pressure of 2-4 atmospheres) with a conductive fluid, expanding the balloon and contacting the lesion, but not at an inflation pressure that substantially displaces the lesion. A voltage pulse can then be applied across the electrodes of the electrode pair to generate acoustic shock waves that propagate through the wall of the angioplasty balloon to the lesion. Once the lesion is spalled by the acoustic shock waves, the balloon can further expand, increasing the cross-sectional area of ​​the cavity and improving blood flow through it. Alternative devices for delivering IVL therapy can be in closed volumes other than an angioplasty balloon, such as caps, variable compliance balloons, or other enclosures. Despite these advances, currently available shockwave catheters can also encounter problems with ischemia due to restricted blood flow while the balloon is inflated during the procedure. Summary of the Invention [Means for solving the problem]

[0010] Quick Overview According to one aspect, a catheter includes a shockwave generator surrounded by a balloon and at least one channel that allows blood to flow past the balloon while the balloon is inflated. Unlike traditional angioplasty catheters that rely on contact with a pressurized balloon to push back plaque, the catheters described herein can better utilize multiple balloon configurations because the shockwave device generates shockwaves that radiate outward to break up the blockage, eliminating the need to repeatedly deflate, rotate, and inflate the shockwave catheter to effectively reduce plaque within a body cavity. Furthermore, while providing a channel that allows blood flow, the catheters described herein achieve improved calcification reduction in single-balloon configurations because the shockwaves can break up the blockage while the balloon is inflated.

[0011] According to one aspect, a catheter for treating a stenosis in a body cavity can include an elongated tube, at least one shock wave generator with at least one electrode pair, at least one balloon sealed to a distal end of the elongated tube and surrounding the at least one shock wave generator, the at least one balloon being capable of being filled with a conductive fluid, and at least one channel that allows blood to flow through the body cavity past the at least one balloon while the at least one balloon is inflated.

[0012] The at least one channel may allow blood to flow through the body cavity at a rate that is at least 50% of the normal rate of blood flow through the body cavity when the catheter is not positioned within the body cavity. The at least one channel may be defined by at least one lumen extending outside the elongated tube. The at least one lumen may extend outside the outer surface of the at least one balloon. The at least one channel may extend within the elongated tube. The elongated tube may include at least one opening to the at least one channel, the at least one opening being located proximal to the at least one balloon for allowing blood to flow into or out of the at least one channel, and at least one opening from the at least one channel to the at least one channel, the at least one opening being located distal to the at least one balloon for allowing blood to flow into or out of the at least one channel.

[0013] The catheter may include multiple balloons and multiple shock wave generators, each balloon of the multiple balloons sealed to a region of the elongated tube and surrounding one or more of the multiple shock wave generators, and at least one channel may be defined by spacing between the multiple balloons. The multiple balloons may be at least three balloons. A cross-section of each of the at least three balloons may be circular. A cross-section of each of the at least three balloons may be elliptical. At least one balloon may include multiple lobes extending outward from the elongated tube, and at least one channel may be defined by spacing between the multiple lobes of the at least one balloon. The at least one balloon may include a crescent shape when inflated, and the at least one channel may be defined by a space between the at least one balloon and the body cavity. The at least one balloon may include a double crescent shape when inflated, and the at least one channel may be defined by a space between the at least one balloon and the body cavity. The elongate tube may include a guidewire lumen for receiving a guidewire, and the catheter may be configured to be advanced over the guidewire into the body lumen.

[0014] According to one aspect, a system for treating a stenosis in a body cavity can include a catheter comprising an elongated tube, at least one shock wave generator comprising at least one electrode pair, at least one balloon sealed to a distal end of the elongated tube and surrounding the at least one shock wave generator, the at least one balloon capable of being filled with a conductive fluid, and at least one channel for allowing blood to flow through the body cavity past the at least one balloon while the at least one balloon is inflated, and a power source configured to apply voltage pulses to the at least one shock wave generator to generate shock waves for treating the stenosis.

[0015] The at least one channel may allow blood to flow through the body cavity at a rate that is at least 50% of the normal rate of blood flow through the body cavity when the catheter is not positioned within the body cavity. The at least one channel may be defined by at least one lumen extending outside the elongated tube. The at least one lumen may extend outside the outer surface of the at least one balloon. The at least one channel may extend within the elongated tube. The elongated tube may include at least one opening to the at least one channel, the at least one opening being located proximal to the at least one balloon for allowing blood to flow into or out of the at least one channel, and at least one opening from the at least one channel to the at least one channel, the at least one opening being located distal to the at least one balloon for allowing blood to flow into or out of the at least one channel.

[0016] The catheter may include multiple balloons and multiple shock wave generators, each balloon of the multiple balloons sealed to a region of the elongated tube and surrounding one or more of the multiple shock wave generators, and at least one channel may extend between the multiple balloons. The multiple balloons may be at least three balloons. A cross-section of each of the at least three balloons may be circular. A cross-section of each of the at least three balloons may be circular. At least one balloon may include multiple lobes extending outward from the elongated tube, and at least one channel may be defined by a spacing between the multiple lobes of the at least one balloon. When inflated, the at least one balloon may include a crescent shape, and the at least one channel may be defined by a spacing between the multiple lobes of the at least one balloon. When inflated, the at least one balloon may include a double crescent shape, and the at least one channel may be defined by a spacing between the multiple lobes of the at least one balloon. The elongate tube may include a guidewire lumen for receiving a guidewire, the catheter being configured to be advanced into the body lumen over the guidewire.

[0017] According to one aspect, a method for treating a stenosis in a body cavity can include advancing a catheter within the body cavity to a position proximate the stenosis; inflating at least one balloon of the catheter, wherein an outer surface of the at least one balloon contacts the body cavity while the at least one balloon is inflated and blood is allowed to flow through the body cavity past the at least one balloon; and generating shock waves via at least one shock wave generator of the catheter while blood is flowing through the body cavity past the at least one balloon.

[0018] The method may include advancing a guidewire within the body lumen to locate the stenosis and advancing a catheter over the guidewire. The method may include retracting the guidewire before inflating the balloon. The method may include retracting the guidewire so that a distal end of the guidewire is located proximal to a proximal end of the balloon. Retracting the guidewire may include withdrawing the guidewire from the body lumen. [Brief explanation of the drawings]

[0019] Brief description of the diagram Illustrative aspects of the present disclosure are described in detail below with reference to the following drawings: The embodiments and drawings disclosed herein are intended to be considered illustrative, not limiting, in nature.

[0020] [Figure 1] FIG. 1 illustrates a system including an exemplary shockwave catheter used to treat a stenosis in a blood cavity in accordance with one or more aspects of the present disclosure.

[0021] [Figure 2A] FIG. 2A illustrates the distal end of an exemplary shock wave perfusion balloon catheter with an internal channel, in accordance with one or more aspects of the present disclosure.

[0022] [Figure 2B] FIG. 2B illustrates a cross-sectional view of an exemplary elongated tube with an internal channel usable for a shock wave perfusion balloon catheter, in accordance with one or more aspects of the present disclosure.

[0023] [Figure 2C] FIG. 2C illustrates a cross-sectional view of an exemplary elongate tube with a central guidewire lumen and an internal channel usable for a shock wave perfusion balloon catheter in accordance with one or more aspects of the present disclosure.

[0024] [Figure 3A]FIG. 3A illustrates the distal end of an exemplary shock wave perfusion balloon catheter having at least one external lumen usable for the shock wave perfusion balloon catheter, in accordance with one or more aspects of the present disclosure.

[0025] [Figure 3B] FIG. 3B illustrates a cross-sectional view of the distal end of the shock wave perfusion balloon catheter of FIG. 3A.

[0026] [Figure 4A] FIG. 4A illustrates the distal end of an exemplary trilobe balloon shockwave catheter in accordance with one or more aspects of the present disclosure.

[0027] [Figure 4B] FIG. 4B illustrates a cross-sectional view of a trilobe balloon shockwave catheter with a circular balloon, in accordance with one or more aspects of the present disclosure.

[0028] [Figure 4C] FIG. 4C illustrates a cross-sectional view of a trilobe balloon shockwave catheter with an oval balloon, in accordance with one or more aspects of the present disclosure.

[0029] [Figure 5] FIG. 5 illustrates the distal end of an exemplary trilobe balloon shockwave catheter with a central elongated tube, in accordance with one or more aspects of the present disclosure.

[0030] [Figure 6A] FIG. 6A illustrates the distal end of a crescent-shaped balloon shockwave catheter according to one or more aspects of the present disclosure.

[0031] [Figure 6B] FIG. 6B illustrates a cross-sectional view of the catheter of FIG. 6A positioned within a body cavity, in accordance with one or more aspects of the present disclosure.

[0032] [Figure 7A]FIG. 7A illustrates the distal end of a double crescent-shaped balloon shockwave catheter in accordance with one or more aspects of the present disclosure.

[0033] [Figure 7B] FIG. 7B illustrates a cross-sectional view of the catheter of FIG. 7A positioned within a body cavity, in accordance with one or more aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0034] Detailed Description The following description is presented to enable those skilled in the art to make and use the various embodiments and aspects thereof disclosed herein. Descriptions of specific devices, assemblies, techniques, and applications are provided by way of example only. Various modifications to 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 and aspects thereof. Thus, the various embodiments and aspects thereof are not intended to be limited to the examples described and shown herein, but are to be accorded the scope consistent with the claims.

[0035] Described herein are balloon catheters that incorporate at least one channel that allows blood to flow past the balloon while the balloon is inflated. When the catheter is positioned within a body cavity (such as a vessel or valve), the channel acts as a bypass around the inflated balloon of the catheter so that blood flow through the body cavity is not generally completely blocked during the procedure.

[0036] The at least one channel can be provided in several different ways. In some examples, the channel extends within an elongated tube within which the balloon of the catheter is sealed. In some examples, the channel is provided by an external lumen extending outside the balloon. In some examples, the at least one channel is provided by the configuration of one or more balloons. For example, the catheter can include multiple balloons spaced apart from one another such that the spacing between the balloons forms the at least one channel. The catheter can include a single balloon with multiple lobes, such as a trilobal balloon, which has lobes extending outward from the elongated tube within which the trilobal balloon is sealed. In such a configuration, the channel (or multiple channels) is defined by the space between the lobes of the trilobal balloon. A trilobal balloon can have multiple circular and / or oval balloons. The catheter can include a balloon shaped to not occupy the entire body cavity when inflated, leaving space for blood to flow past the balloon. For example, the balloon may have a crescent shape that allows blood to flow to the space within the body cavity on the opposite side of the balloon.

[0037] The described catheter designs include at least one shockwave generator with at least one electrode pair within the working length of the catheter, which delivers acoustic shock waves and / or cavitation bubbles to a treatment site adjacent to the catheter's distal tip. For example, as described in U.S. Pat. No. 10,709,462, the entire contents of which are incorporated herein by reference, the first electrode of the shockwave generator can be formed from the side edge of a conductive metal sheath mounted within the catheter. The electrode pair can be formed by positioning a second conductive material at a controlled distance from the conductive sheath (i.e., a gap also called a "spark gap") to enable reproducible arcing across the electrodes for a given current and voltage. In some examples, as described in the above references, the second electrode of the electrode pair can be formed from a conductive portion (e.g., a stripped or uninsulated portion) of a wire extending along the length of the catheter. Additionally or alternatively, as described herein, an exemplary electrode pair can be formed from two cylindrical conductive metal sheaths mounted concentrically within the catheter. Such an electrode assembly may have a relatively small crossing profile, for example, compared to existing electrode assembly designs that have crossing profiles of 0.8 mm to 1.2 mm diameter. Such an electrode assembly design may also facilitate catheter manufacturing by simplifying the process for constructing the electrode assembly.

[0038] Efforts have been made to improve the design of the electrode assemblies included in shock wave and directional cavitation catheters. For example, low-profile electrode assemblies have been developed that reduce the catheter's crossing profile, allowing the catheter to more easily pass through calcified vessels and deliver shock waves into more severely occluded areas of the vasculature. Examples of low-profile electrode designs that can be used in any of the embodiments described herein can be found in U.S. Patent Nos. 8,888,788, 9,433,428, and 10,709,462 (mentioned above), as well as U.S. Patent Application Publication No. 2021 / 0085383, all of which are incorporated herein by reference in their entireties. Other catheter designs improve shock wave delivery, for example, through specific electrode structures and configurations, which direct the shock waves in a forward direction to disrupt tighter and more difficult-to-pass occlusions in the vasculature. Examples of forward firing catheter designs that can be used for the catheter designs described herein can be found in U.S. Patent Nos. 10,966,737, 11,478,261, and 11,596,423, and U.S. Patent Application Publication Nos. 2023 / 0107690 and 2023 / 0165598, all of which are incorporated by reference in their entirety.

[0039] The catheter designs described herein, according to various examples, can be configured so that the flow rate of blood flowing through one or more channels of the catheter when the balloon is fully inflated is at least 50% of the flow rate of blood normally flowing through a body cavity without the catheter disposed therein (i.e., "normal flow rate"). In one or more examples, the flow rate of blood flowing through the channel(s) of the catheter can be less than 50% of the normal flow rate, such as 10%, 15%, 20%, or 25% of the normal flow rate. In one or more examples, the flow rate of blood flowing through the channel(s) of the catheter can be greater than 50% of the normal flow rate, such as 70%, 80%, or 90% of the normal flow rate. It should be understood that the exemplary ranges for blood flow rates set forth in this disclosure include percentage increments and gradients within and around the explicitly disclosed ranges. As used herein, "fully inflated" may mean that the balloon has been inflated until it contacts the body cavity and / or the occluded area of ​​the body cavity during normal operation of the catheter (e.g., when shock waves are being used to treat an occlusion), or that the balloon has been inflated to the maximum amount that it is configured to inflate during normal operation (e.g., when shock waves are being used to treat an occlusion).

[0040] In some embodiments, the blood flow rate through a body lumen when the balloon(s) of the catheter are inflated is proportional to the total cross-sectional area of ​​the catheter's one or more channels relative to the total cross-sectional area of ​​the catheter. For example, a catheter having channel(s) that allows no more than 10% of the normal blood flow rate through a body lumen when the balloon(s) are inflated can have a total channel cross-sectional area that is no more than 10% of the catheter's total cross-sectional area.

[0041] As used herein, the term "electrode" refers to a conductive element (usually made of metal) that receives and subsequently emits current to another conductive element. In the context of this disclosure, electrodes are often positioned relative to one another, such as in an inner-outer electrode arrangement. Thus, as used herein, the term "electrode pair" refers to two electrodes positioned adjacent to one another, such that application of a sufficiently high voltage to the electrode pair causes current to be conducted across a gap (also called a "spark gap") between the two electrodes (e.g., from the inner electrode to the outer electrode, or vice versa, optionally with electricity passing through a conductive fluid or gas between the electrodes). In some contexts, one or more electrode pairs may also be referred to as an electrode assembly. In the context of this disclosure, the term "emitter" broadly refers to the region of the electrode assembly where current is conducted across the electrode pair, generating a shock wave. Emitters can be singular, in pairs, or otherwise arranged together and electrically connected as an emitter assembly. Shock waves can be generated at each electrode pair of the emitter, and therefore the emitter can also be referred to as a "shock wave generator."

[0042] In some embodiments, the IVL catheter is a so-called "rapid exchange" ("Rx") catheter that has an opening through which a guidewire is routed (e.g., longitudinally through an intermediate portion of the central tube). In other embodiments, the IVL catheter can be an "over-the-wire" ("OTW") catheter in which a guidewire lumen is formed through the entire length of the catheter and the guidewire is routed through the proximal end of the hub.

[0043] It should be understood that while the shock wave devices described herein generate shock waves based on high voltage applied to electrodes, in addition to or alternatively, the shock wave device may include a laser and optical fiber as a shock wave emitter system, whereby the laser source delivers energy into the fluid through the optical fiber to form shock waves and / or cavitation bubbles.

[0044] In the following description of various embodiments, reference is made to the accompanying drawings in which it is shown, by way of illustration, specific embodiments that may be practiced. It is to be understood that other embodiments and examples may be practiced and changes may be made without departing from the scope of the present disclosure.

[0045] Additionally, it should be understood that the singular forms "a," "an," and "the," as used in the following description, are intended to include the plural forms as well, unless the context clearly dictates otherwise. The term "and / or," as used herein, should also be understood to refer to and encompass any and all possible combinations of one or more of the associated listed items. Furthermore, it should be understood that the terms "includes," "including," "comprises," and / or "comprising," as used herein, specify the presence of stated features, integers, steps, operations, elements, components, and / or units, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, units, and / or groups thereof. As provided herein, any disclosure of a numerical range describing a dimension or measurement, such as thickness, length, weight, time, frequency, temperature, voltage, current, angle, etc., should be understood to include any numerical increment or gradient within the stated range for the given dimension or measurement.

[0046] FIG. 1 depicts an exemplary system 10 including a shockwave catheter 100 according to one or more examples of the present disclosure. The shockwave catheter 100 includes an elongated tube 104 and a balloon 102. The balloon 102 is circumferentially wrapped around a portion of the elongated tube 104 in a sealed configuration, e.g., via a seal 122. The balloon 102 forms an annular channel 124 around the elongated tube 104 through which a conductive fluid, such as saline, can be accommodated in the balloon 102 via a fill port 126. Once the balloon 102 is filled with the conductive fluid, it can be inflated to gently contact the wall of a body cavity (e.g., the wall of an artery adjacent to a calcified lesion). Unlike conventional angioplasty balloons, which are often inflated to a pressure that causes the exterior of the balloon to frictionally fit against the vessel wall, the balloon 102 herein can be inflated to a relatively low pressure sufficient to form a gentle contact with the wall of the body cavity against a target location within the body cavity. In one or more examples, the conductive fluid may also further include an X-ray contrast fluid to allow fluoroscopic viewing of the catheter by the surgeon during use.

[0047] The elongated tube 104 may include several longitudinal grooves or channels configured to hold wires, fiber optic cables, and / or an inner electrode. The elongated tube 104 of FIG. 1 includes four grooves extending along its length that receive insulated wires 130, 132, 134, and 136 (which, in other embodiments, may be fiber optic cables). The distal ends of the insulated wires connect to several shock wave generators 106 located within the balloon 102 and wound circumferentially around the elongated tube 104. Each of the shock wave generators 106 includes at least one electrode pair, with the electrodes of each pair spaced apart to define a spark gap. The distance between the electrodes of an electrode pair may vary depending on the magnitude of the high voltage pulse applied to the shock wave generator 106. For example, a gap of approximately 0.004 inches to approximately 0.006 inches may be effective for shock wave generation using a voltage pulse of approximately 3,000 V.

[0048] The system 10 includes a power source 150 (e.g., a variable high-voltage pulse generator, a laser pulse generator, etc.) connected to the proximal end of the insulated wire 130 and the insulated wire 136. The insulated wire provides voltage to the shock wave generator 106. When voltage is applied across the insulated wire by the power source 150, each pulse first ionizes the conductive fluid inside the balloon 102, creating small gas bubbles around the shock wave generator 106 that insulate the electrodes. A plasma arc then forms across the gap between the electrodes of the electrode pair, creating a low-impedance path for electrical current to flow freely. Heat from the plasma arc heats the conductive fluid, creating a rapidly expanding vapor bubble. The expansion and collapse of the vapor bubble creates a shock wave that radiates outward through the annular channel 124 in the balloon 102 and then travels through the bloodstream to the calcified lesion adjacent to the balloon 102.

[0049] As shown in FIG. 1 , the catheter 100 has three shockwave generators 106; however, this is provided by way of example only and should not be construed as limiting in any manner, as the catheter 100 can include one shockwave generator, two shockwave generators, or three or more shockwave generators. When the catheter 100 includes multiple shockwave generators, the shockwave generators can be positioned adjacent to one another and longitudinally adjacent to one another so that the shockwave generators can constructively interfere with one another, as described in U.S. Patent Application No. 16 / 967,544, which is incorporated herein by reference. For example, the shockwave generators 106 can be longitudinally spaced less than 6 mm apart, such as spaced apart by a distance of 1 mm to 4 mm (or increments of the distance between them), so that shockwaves generated by the first and second shockwave generators constructively interfere to generate a composite shockwave.

[0050] Furthermore, as described in the above references, a shock wave generator can include multiple electrode pairs configured to constructively interfere with each other. For example, a single shock wave generator can include multiple electrode pairs located at essentially the same longitudinal position as each other but circumferentially offset from each other by an angle less than 180 degrees, such as between 40 and 140 degrees, between 65 and 125 degrees, or between 80 and 100 degrees, such that shock waves generated by a first electrode pair and a second electrode pair can constructively interfere to generate a composite shock wave.

[0051] The elongated tube 104 includes a lumen through which a guidewire 120 is inserted. During surgery, the physician uses the guidewire 120 to guide the elongated tube 104 to a position within the body cavity adjacent to a calcified lesion. Once positioned, a power source 150 is used to deliver a series of pulses, generating a series of shock waves at a shockwave generator 106 within the balloon 102 and within the body cavity being treated. The magnitude of the shock waves can be controlled by controlling the magnitude, current, duration, and repetition rate of the pulse voltage supplied by the power source 150. The physician can start with low-energy shock waves and increase the energy as needed to break up the calcified plaque. Such shock waves are conducted through the conductive fluid within the balloon 102 and through the blood to the calcified lesion, where the energy breaks down or fractures the hardened plaque.

[0052] In one or more examples, the system 10 can be configured to generate shock waves via a laser output. The generator 150 can be a laser pulse generator that delivers laser pulses to the shock wave generator 106 via a fiber optic cable rather than a wire. In such an implementation, the optical fiber can be exposed to a conductive fluid, allowing the laser pulses to be emitted directly into the fluid. When the laser pulses are delivered to the shock wave generator 106, laser-generated bubbles can form (in a manner similar to that described for electric arc shock wave formation), generating shock waves during the rapid expansion and collapse of the laser-generated bubbles.

[0053] FIG. 2A illustrates the distal end of an exemplary shock wave perfusion balloon catheter 200 with an internal channel. The catheter 200 includes an elongated tube 204 and a balloon 202 sealed to the elongated tube 204. The balloon 202 surrounds a pair of shock wave generators 206 circumferentially wrapped around the elongated tube 204. In one or more examples, the balloon 202 can surround more or fewer than two shock wave generators 206. Each of the shock wave generators 206 includes at least one electrode pair, with the electrodes of each electrode pair spaced apart to form a spark gap. The balloon 202 can be filled with a conductive fluid, such as saline, such that the balloon 202 expands (i.e., inflates) and provides an annular channel between the inner surface of the balloon 202 and the shock wave generator 206.

[0054] 1 , can be connected to a pulsed power source such as power source 150 to supply a voltage to a shock wave generator within a balloon 202 of the catheter 200, generating shock waves in a spark gap between electrodes of an electrode pair of the shock wave generator 206, etc. The catheter 200 is shown with a pair of shock wave generators 206. However, this is provided for illustrative purposes only, and the catheter 200 can have a single shock wave generator 206 or two or more shock wave generators 206 within the balloon 202.

[0055] The catheter 200 includes an internal channel for allowing blood to flow past the balloon 202 while it is inflated. The internal channel extends inside the elongated tube 204 and includes at least one proximal hole 208 located proximally on the proximal side of the balloon 202 and at least one distal hole 210 located distally on the distal side of the balloon 202. When the balloon 202 is positioned within a body cavity and filled with fluid (i.e., when inflated), blood can enter the internal channel via the proximal hole 208, flow through the internal channel, and exit the internal channel via the distal hole 210. When blood is flowing in the opposite direction, blood can enter the internal channel via the distal hole 210 and exit the internal channel via the proximal hole 208. Thus, the internal channel provides a channel for allowing blood to flow through the body cavity and past the balloon 202 while it is inflated. As shown, the elongate tube 204 includes a pair of proximal holes 208; however, the elongate tube 204 may include a single proximal hole 208 or more than one proximal hole 208. Additionally, the elongate tube 204 may include more or fewer distal holes 210 than the four distal holes 210 illustrated in FIG. 2A.

[0056] The flow rate of blood flowing through the internal channel of catheter 200 when balloon 202 is fully inflated can be approximately 50% of the flow rate of blood that normally flows through a body cavity when catheter 200 is not disposed within the body cavity (i.e., the "normal flow rate"). In one or more examples, the flow rate of blood flowing through the internal channel of catheter 200 can be less than 50% of the normal flow rate, such as 10%, 15%, 20%, or 25% of the normal flow rate. In one or more examples, the flow rate of blood flowing through the internal channel of catheter 200 can be greater than 50% of the normal flow rate, such as 70%, 80%, or 90% of the normal flow rate. Balloon 202 can be configured to contact the body cavity and / or occluded areas of the body cavity when fully inflated. Alternatively, balloon 202 can be configured to expand only a specified amount when fully inflated (e.g., expand 50% in diameter relative to its uninflated diameter).

[0057] The balloon 202 is formed from a material with elastomeric properties so that the balloon can accommodate inflation pressures up to approximately 6 atmospheres. In one or more examples, the balloon 202 can be sufficiently flexible to accommodate inflation pressures greater than 6 atmospheres, such as inflation pressures up to 10 atmospheres. The balloon 202 can be formed from polymeric materials currently used in the medical device industry. The balloon 202 can be configured to assume a circular shape (from a cross-sectional perspective) when inflated. Optionally, the balloon 202 can be configured to assume an oval shape or any other suitable shape. The balloon 202 can include structural support members, such as skeletal struts or ribs (e.g., as shown in FIG. 4B ), within the balloon material that cause the balloon 202 to assume a particular shape when inflated. Structural support members such as these can be foldable so that they fold around the elongated tube 204 when the balloon 202 is unfilled, and can incorporate a resilient mechanism, such as a spring, that causes the structural support members to expand away from the elongated tube 204 when the balloon 202 is filled.

[0058] 2B illustrates a cross-sectional view of an exemplary elongated tube 203 with an internal channel usable for a shock wave perfusion balloon catheter. The elongated tube 203 is a hollow tube forming a single lumen 230. Thus, when blood flows through the elongated tube 203 (e.g., by entering or exiting through holes located proximally and distally to the balloon), the blood flows through the hollow interior of the elongated tube 203. The elongated tube 203 has a diameter d1, which may be, for example, 0.066 inches (5 French) to 0.1 inches (8 French).

[0059] 2C illustrates a cross-sectional view of an exemplary elongated tube 205 with a central guidewire lumen and an internal channel usable for a shock wave perfusion balloon catheter. In contrast to elongated tube 203, elongated tube 205 includes a central guidewire tube 209 that defines a central guidewire lumen 290. Thus, elongated tube 205 includes a pair of lumens, namely, central guidewire lumen 290 and outer blood flow lumen 250, with the internal channel being defined by an annular lumen formed in the space between elongated tube 205 and central guidewire tube 209. When blood flows through elongated tube 205 (e.g., by entering or exiting via holes located proximally and distally to the balloon), the blood flows through blood flow lumen 250. Elongated tube 205 has a diameter d2, which may be the same as diameter d1 of elongated tube 203. Alternatively, diameter d2 of elongate tube 205 may be larger than diameter d1 of elongate tube 203, e.g., between 0.1 inch (8 French) and 0.13 inch (10 French). Central guidewire tube 209 may have a diameter of approximately 0.015 to 0.016 inch such that central guidewire tube 209 can accommodate a guidewire with a diameter of approximately 0.014 inch. In one or more examples, central guidewire tube 209 may be sized to receive a guidewire with a diameter of up to 0.035 inch.

[0060] The elongated tube 203 of Figure 2B or the elongated tube 205 of Figure 2C can be used as the elongated tube 204 of the catheter 200 of Figure 2A. When the catheter 200 includes the elongated tube 203 of Figure 2B, a guidewire can be first inserted into the elongated tube 203 to position the balloon 202 near the calcification in the body cavity, and then pulled back prior to initiating the procedure. That is, the guidewire can be pulled back prior to filling the balloon 202 with a conductive fluid and applying a voltage to the shock wave generator 206 to generate shock waves. The guidewire can be completely pulled back from the catheter 200 (e.g., removed from the body) or only partially pulled back (e.g., pulled back to a position proximal to the proximal hole 208 so that the guidewire is not located in a channel through which blood flows, bypassing the balloon 202).

[0061] Elongated tube 204 may optionally include a barrier 211 located distal to distal hole 210 to help direct blood out of the interior channel through distal hole 210. Additionally or alternatively, elongated tube 204 may include a barrier 211 located proximal to proximal hole 208 to help direct blood out of the interior channel through proximal hole 208 depending on the direction of blood flow through the body cavity. Barrier 211 may be, for example, a delivery valve, umbrella seal, sealing member, check valve, etc., having a central opening that allows a guidewire to pass therethrough.

[0062] FIG. 3A illustrates the distal end of an exemplary shock wave perfusion balloon catheter 300 having at least one external lumen 312 (alternatively referred to as a bypass lumen). The catheter 300 includes an elongated tube 304 and a balloon 302 sealed to the elongated tube 304. The elongated tube 304 may include a hollow interior for receiving a guidewire. The balloon 302 surrounds a pair of shock wave generators 306 circumferentially wrapped around the elongated tube 304. In one or more examples, the balloon 302 can surround more or fewer than two shock wave generators 306. Each of the shock wave generators includes at least one electrode pair, with the electrodes of each electrode pair spaced apart to form a spark gap. The balloon 302 can be filled with a conductive fluid, such as saline, so that the balloon 302 expands and provides an annular channel between the inner surface of the balloon 302 and the shock wave generator 306.

[0063] 1 , can be connected to a pulsed power source such as power source 150 to supply a voltage to a shock wave generator 306 within the balloon 302, generate shock waves in a spark gap between a pair of electrodes of the shock wave generator 306, etc. The catheter 300 is shown with a pair of shock wave generators 306. However, this is provided for illustrative purposes only, and the catheter 300 may have a single shock wave generator 306 within the balloon 302, or may have two or more shock wave generators 306.

[0064] Catheter 300 is similar to catheter 200 of FIG. 2A except that instead of an internal channel inside elongated tube 304, catheter 300 includes at least one external lumen 312. External lumen 312 is located along the outer surface of balloon 302 and is attached to elongated tube 304 at a location proximal to the proximal end of balloon 302 and distal to the distal end of balloon 302 such that external lumen 312 acts as a bypass channel around balloon 302. External lumen 312 can be attached to elongated tube 304 in a sealing manner at each of these locations. External lumen 312 includes at least one proximal hole 308 located at the proximal end of external lumen 312 and at least one distal hole 310 located at the distal end of external lumen 312.

[0065] When the balloon 302 is positioned within a body cavity and filled with fluid (i.e., inflated), blood within the body cavity can enter the external lumen 312 through the proximal hole 308, travel through the external lumen 312, and exit the external lumen 312 through the distal hole(s) 310. When blood is flowing in the opposite direction, blood can enter the external lumen 312 through the distal hole(s) 310 and exit the external lumen 312 through the proximal hole(s) 308. FIG. 3B illustrates a cross-sectional view of the distal end of the shock wave perfusion balloon catheter 300 within a body cavity 315. When inflated, the balloon 302 expands to fill the space within the body cavity 315, but does not fill the space occupied by the external lumen 312. Therefore, while the balloon 302 is inflated, blood can continue to flow through the body cavity 315 via the internal lumen 312. Thus, the outer lumen 312 provides a channel that allows blood to flow through the body cavity and past the balloon 302 while the balloon 302 is inflated. In one or more examples, the catheter 300 can include multiple outer lumens 312.

[0066] The flow rate of blood flowing through the external lumen 312 of the catheter 300 when the balloon 302 is fully inflated can be approximately 50% of the flow rate of blood normally flowing through a body cavity when the catheter 300 is not disposed within the body cavity (i.e., the "normal flow rate"). In one or more examples, the flow rate of blood flowing through the external lumen 312 of the catheter 300 can be less than 50% of the normal flow rate, such as 10%, 15%, 20%, or 25% of the normal flow rate. In one or more examples, the flow rate of blood flowing through the external lumen 312 of the catheter 300 can be greater than 50% of the normal flow rate, such as 70%, 80%, or 90% of the normal flow rate. The balloon 302 can be configured to contact the body cavity and / or occluded areas of the body cavity when fully inflated. Alternatively, the balloon 302 can be configured to expand only a specified amount when fully inflated (e.g., expand 50% in diameter relative to its uninflated diameter).

[0067] The outer lumen 312 can be formed from a somewhat flexible material that allows the outer lumen 312 to bend outward when the balloon 302 is inflated. For example, the outer lumen 312 can be formed from polyurethane, nylon, polyethylene (PE), polyolefin copolymer (POC), polyethylene terephthalate (PET), or any combination thereof. The outer lumen 312 can be positioned between the balloon 302 and the calcification when the catheter 300 is used to treat the calcification in a body cavity. Therefore, when a voltage is applied to the shock wave generator 306 (e.g., via a wire as shown in FIG. 1 ) and the shock wave begins to propagate outward, the shock wave can travel through the balloon 302 and the outer lumen 312 before traveling to the calcification. Therefore, the material of the outer surface of the outer lumen 312 can be relatively strong so that contact with the calcification in the body cavity does not damage the outer lumen 312. In the expanded configuration, the balloon 302 does not need to be under pressure. Thus, the pressure pressing the outer lumen 312 against the calcification may not be sufficient to buckle (e.g., flatten the channel) the outer lumen 312. The outer lumen 312 may be removable so that the outer lumen 312 can be removed and a new outer lumen 312 attached to the catheter 300. The outer lumen 312 may be fixedly attached to the outer surface of the balloon 302, for example, via one or more seals 311.

[0068] The shockwave catheters described herein may include multiple balloons. For example, FIG. 4A illustrates the distal end of an exemplary tri-balloon shockwave catheter 400. The catheter 400 includes a central elongated tube 404 that may include a hollow interior for receiving a guidewire. Three side tubes 430 (two are shown in the view depicted in FIG. 4A) are attached to and extend outward from the elongated tube 404. A balloon 402 is sealed to each side tube 430. The tri-balloon shockwave catheter 400 includes three side tubes 430, one for each balloon 402. This is provided by way of example only; multi-balloon shockwave catheters as described herein may include various multi-balloon configurations, such as a quad-balloon catheter containing four side tubes and four balloons, or a bi-balloon catheter containing two side tubes and two balloons.

[0069] Each balloon 402 surrounds a pair of shock wave generators 406 circumferentially wrapped around one of the side tubes 430. In one or more examples, each balloon 402 can surround more or fewer than two shock wave generators 406. Each shock wave generator 406 includes at least one electrode pair, with the electrodes of each electrode pair spaced apart to form a spark gap. The balloons 402 can be filled with a conductive fluid, such as saline, so that the balloons 402 expand and provide an annular channel between the inner surface of the balloon 402 and each shock wave generator 406.

[0070] The catheter 400 can be used with the catheter 100 of the system 10 of FIG. 1 and can be connected to a pulsed power source, such as the power source 150, to supply a voltage to the shock wave generators 406 in each balloon 402, generating shock waves in a spark gap between the electrode pairs of the shock wave generators 406. As shown in FIG. 4A , each balloon 402 surrounds a pair of shock wave generators 406. However, this is provided for illustrative purposes only, and the catheter 400 can be configured to include a single shock wave generator 406 in each balloon 402, two or more shock wave generators 406 in each balloon 402, or different numbers of shock wave generators 406 in different balloons 402 (e.g., one shock wave generator 406 in a first balloon and two shock wave generators 406 in a second balloon). The balloons 402 of the catheter 400 can be several shapes. For example, the balloon 402 may be circular or oval from a cross-sectional perspective. The balloon 402 may be configured to assume a circular or oval shape based on manufacturing steps during the balloon-forming process.

[0071] The side tubes 430 can be connected to the elongated tube 404 in a sealed manner. When the catheter 400 is positioned within a body cavity and the balloons 402 are filled with fluid (i.e., inflated), the side tubes 430 extend outward from the central elongated tube 404, thereby creating a channel (or channels) in the spaces between the balloons 402. Blood can therefore flow through the channel(s) defined by the spaces between the balloons 402 and, therefore, past the balloons 402 through the body cavity while the balloons 402 are inflated. The channel(s) between the balloons 402 are more clearly visible in a cross-sectional view of the catheter 400. FIG. 4B illustrates a cross-sectional view of a trilobe balloon shockwave catheter 400 with a circular balloon 402, and FIG. 4C illustrates a cross-sectional view of a trilobe balloon shockwave catheter 400 with an oval balloon 402.

[0072] The diagrams shown in Figures 4B and 4C depict a catheter 400 within a body cavity 415. As shown in Figure 4B, at least one channel 407 extends between the balloons 402, providing space for blood to flow past the balloons 402 of the catheter 400 during a procedure. Similarly, as shown in Figure 4C, which depicts the catheter 400 within an occluded body cavity 415, at least one channel 407 extends between an occluded region 450 of the body cavity 415 and the balloon 402 to allow blood to continue to flow through the body cavity 415 during a procedure. As described above, the balloon of a shockwave catheter such as catheter 400 can include structural support members (e.g., ribs, struts, scaffolding, springs, shape-memory materials, etc.) that cause the balloon to assume a particular shape when inflated. An exemplary structural support member 440 is shown within the balloon 402 of the embodiment shown in Figure 4B. These structural support members 440 can expand away from the side tube 430 when the balloon 402 is inflated, causing the balloon 402 to assume the circular shape shown. When the balloon 402 is deflated, the structural support members 440 can fold around the side tube 430.

[0073] When the balloon 402 is filled with fluid, the overall diameter of the catheter 400 can be, for example, 0.066 inches to 0.1 inches (5 to 8 French). In one or more examples, the overall diameter of the catheter 400 can be larger, such as 0.1 inches to 0.197 inches (8 to 15 French). The catheter 400 can be suitable for treating a wide range of body cavities, such as the aorta, aortic valve, and peripheral arteries.

[0074] The flow rate of blood flowing through the channels between the balloons 402 of the catheter 400 when the balloons 402 are fully inflated can be approximately 50% of the flow rate of blood that normally flows through a body cavity when the catheter 400 is not disposed within the body cavity (i.e., the "normal flow rate"). In one or more examples, the flow rate of blood flowing through the channels between the balloons 402 of the catheter 400 can be less than 50% of the normal flow rate, such as 10%, 15%, 20%, or 25% of the normal flow rate. In one or more examples, the flow rate of blood flowing through the channels between the balloons 402 of the catheter 400 can be greater than 50% of the normal flow rate, such as 70%, 80%, or 90% of the normal flow rate. The catheter 400 can be configured so that the balloon 402 contacts the body cavity and / or an occluded area of ​​the body cavity when the balloon 402 is fully inflated. Alternatively, the balloon 402 can be configured to expand only a specified amount when fully inflated (e.g., expand 50% in diameter relative to its uninflated diameter).

[0075] As shown in FIG. 4A , the balloons 402 of the catheter 400 are completely separate from one another, as each is sealed to a separate side tube 430 of the catheter 400. In one or more examples, a multi-lobe balloon catheter may instead incorporate a single balloon including multiple lobes sealed to a central elongate tube 404. An example of this is shown in FIG. 5 , which illustrates the distal end of an exemplary tri-lobe balloon shockwave catheter 500 comprising a central elongate tube 504. The catheter 500 includes a tri-lobe balloon 502 sealed to the elongate tube 504. Multiple shockwave generators 506 are wrapped circumferentially around the elongate tube 504 within the tri-lobe balloon 502. The elongate tube 504 includes a hollow interior that receives a guidewire 520, which is shown protruding from the distal end of the elongate tube 504.

[0076] The catheter 500 can be used with the catheter 100 of the system 10 of FIG. 1 , and can be connected to a pulsed power source, such as the power source 150, to supply a voltage to a shock wave generator 506 within the trilobal balloon 502, generating shock waves in a spark gap between a pair of electrodes of the shock wave generator 506. As shown in FIG. 5 , the shock wave generator 506 is located on an elongated tube 504 and does not extend into the lobes of the trilobal balloon 502. When generating shock waves from the shock wave generator 506, the shock waves can propagate generally outward. In one or more examples, the shock wave generator 506 can be oriented to propagate shock waves primarily along the direction of the lobes of the trilobal balloon 502, such that the shock waves propagate through the conductive fluid within the lobes. Alternatively, or in addition, the shock wave generator 506 can be oriented to propagate shock waves primarily in the space between the lobes of the trilobal balloon 502. In one or more examples, the catheter 500 can include side tubes (similar to the side tubes 430 in FIG. 4A ) that extend into the lobes of the balloon 502 and include additional shock wave generators. Thus, the catheter 500 can include shock wave generators 506 distributed throughout the lobes of the balloon 502, rather than being located only in the center of the balloon 502 surrounding the elongated tube 504.

[0077] The lobes of the trilobal balloon 502 extend outward from the elongated tube 504 when filled with fluid (i.e., when inflated). When deflated, the lobes of the trilobal balloon 502 may be positioned closely adjacent to the elongated tube 504, improving maneuverability of the catheter 500. When inflated, the lobes of the trilobal balloon 502 may contact the body cavity and act to hold the catheter 500 in place within a calcified region of the body cavity (e.g., as shown in FIG. 4C ). Channel(s) are defined by the spaces between the lobes of the trilobal balloon 502, which provide space for blood to flow through the body cavity and past the lobes of the trilobal balloon 502 when the trilobal balloon 502 is inflated. Compared to the catheter 400 of FIG. 4A , the channel(s) extending between the lobes of the trilobal balloon 502 may be larger and therefore provide a greater flow rate. The trilobal balloon 502 is provided by way of example only, and catheters in accordance with the invention disclosed herein may include balloons having various multi-lobal configurations, such as a quad-lobe balloon having four lobes, a dilobe balloon having two lobes, etc.

[0078] The flow rate of blood flowing through the interlobe channels of the trilobe balloon 502 of the catheter 500 when the trilobe balloon 502 is fully inflated can be approximately 50% of the flow rate of blood that normally flows through a body cavity when the catheter 500 is not disposed within the body cavity (i.e., the "normal flow rate"). In one or more examples, the flow rate of blood flowing through the interlobe channels of the trilobe balloon 502 of the catheter 500 can be less than 50% of the normal flow rate, such as 10%, 15%, 20%, or 25% of the normal flow rate. In one or more examples, the flow rate of blood flowing through the interlobe channels of the trilobe balloon 502 of the catheter 500 can be greater than 50% of the normal flow rate, such as 70%, 80%, or 90% of the normal flow rate. The trilobe balloon 502 can be configured such that the lobes contact the body cavity and / or the occluded area of ​​the body cavity when fully inflated. Alternatively, the trilobal balloon 502 may be configured to expand only a specified amount when fully inflated (eg, expand in diameter by 50% relative to its uninflated diameter).

[0079] As noted above, multi-balloon shockwave catheters as described herein can include a variety of multi-balloon configurations and are not limited to tri-balloon designs. For example, a quad-balloon shockwave catheter can include four side tubes and four balloons, a quint-balloon shockwave catheter can include five side tubes and five balloons, and a sext-balloon shockwave catheter can include six side tubes and six balloons. In addition, multi-balloon shockwave catheters can incorporate balloons of different sizes. For example, the three balloons 402 of the tri-balloon shockwave catheter 400 can each be a different size and / or shape (e.g., a first circular balloon, a second oval balloon, and a third circular balloon with a different diameter than the first circular balloon).

[0080] 6A illustrates the distal end of a crescent-shaped balloon shockwave catheter 600. The catheter 600 includes a crescent-shaped balloon 602 sealed within an elongated tube 604. Multiple shockwave generators 606 are wrapped circumferentially around the elongated tube 604 within the balloon 602. The elongated tube 604 includes a hollow interior that receives a guidewire 620, which is shown protruding from the distal end of the elongated tube 604.

[0081] The catheter 600 can be used with the catheter 100 of the system 10 of FIG. 1 and can be connected to a pulsed power source, such as the power source 150, to supply a voltage to a shock wave generator 606 within the balloon 602, generating shock waves at a spark gap between a pair of electrodes of the shock wave generator 606. As shown in FIG. 6A , the shock wave generator 606 is positioned at the center of the balloon 602. In one or more examples, the catheter 600 can include a side tube (similar to the side tube 430 of FIG. 4A ) that extends to the apex of the crescent (e.g., outward from the center of the balloon) and includes additional shock wave generators. Thus, the catheter 600 can include shock wave generators 606 distributed throughout the balloon 602, rather than being located only at the center of the balloon 602 surrounding the elongated tube 604.

[0082] When generating shock waves from the shock wave generator 606, the shock waves can propagate generally outward. In one or more examples, the shock wave generator 606 can be oriented to propagate shock waves generally upward with respect to the view shown in Figure 6B (as indicated by arrow 607 in Figure 6B). Alternatively, or in addition, the shock wave generator 606 can be oriented to propagate shock waves in various directions outward from the elongated tube 604.

[0083] FIG. 6B illustrates a cross-sectional view of the catheter 600 of FIG. 6A positioned within a body cavity 615. When the balloon 602 is filled with fluid (i.e., inflated), the balloon 602 assumes a crescent shape. The balloon 602 can be configured and / or shaped to assume a crescent shape when inflated based on manufacturing steps during the balloon-forming process. The balloon 602 may include internal structural features (e.g., ribs, struts, scaffolding, springs, shape-memory materials, etc.) that ensure the balloon 602 assumes a crescent shape when inflated. When deflated, the balloon 602 may be positioned closely adjacent to the elongated tube 604, which improves the maneuverability of the catheter 600. When inflated, the crescent shape of the balloon 602 leaves an opening 617 (defined by the crescent shape of the balloon 602) that provides a channel that allows blood to flow past the balloon 602 through the body cavity 615 while the balloon 602 is inflated.

[0084] The flow rate of blood flowing through the channels (i.e., openings 617) of catheter 600 when balloon 602 is fully inflated can be approximately 50% of the flow rate of blood that normally flows through a body cavity when catheter 600 is not disposed within the body cavity (i.e., the "normal flow rate"). In one or more examples, the flow rate of blood flowing through the channels of balloon 602 can be less than 50% of the normal flow rate, such as 10%, 15%, 20%, or 25% of the normal flow rate. In one or more examples, the flow rate of blood flowing through the channels of balloon 602 can be greater than 50% of the normal flow rate, such as 70%, 80%, or 90% of the normal flow rate. Balloon 602 can be configured to contact the body cavity and / or occluded areas of the body cavity when fully inflated. Alternatively, balloon 602 can be configured to expand only a specified amount when fully inflated (e.g., expand 50% in diameter relative to its uninflated diameter).

[0085] 6B , balloon 602 contacts only a portion (e.g., only the upper portion) of the wall of body cavity 615. In use, a surgeon may treat each portion of body cavity 615 sequentially by rotating balloon 602 within body cavity 615, for example, by rotating elongated tube 604, causing balloon 602 to contact new portions of the wall of body cavity 615. For example, a surgeon may rotate elongated tube 604 clockwise in incremental steps to treat the entire body cavity 615. Beneficially, to treat the entire body cavity 615 using catheter 600, a surgeon does not need to deflate and re-inflate balloon 602, as may be necessary when relying on a balloon that does not include a channel that allows blood to flow past the catheter during treatment.

[0086] FIG. 7A illustrates the distal end of a double-crescent-shaped balloon shockwave catheter 700. The catheter 700 includes a double-crescent-shaped balloon 702 sealed to an elongated tube 704. As shown more clearly in FIG. 7B, which illustrates a cross-sectional view of the catheter 700 of FIG. 7A positioned within a body cavity 715, when the balloon 702 is filled with fluid (e.g., inflated), the balloon 702 has two concave regions (e.g., two "crescents"). That is, when the balloon 702 is filled with fluid, the balloon 702 assumes a double-crescent shape. Multiple shockwave generators 706 are wrapped circumferentially around the elongated tube 704 within the balloon 702. The elongated tube 704 includes a hollow interior that receives a guidewire 720, which is shown protruding from the distal end of the elongated tube 704.

[0087] The catheter 700 can be used with the catheter 100 of the system 10 of FIG. 1 and can be connected to a pulsed power source, such as the power source 150, to supply a voltage to a shock wave generator 706 within the balloon 702, generating shock waves at a spark gap between a pair of electrodes of the shock wave generator 706. As shown in FIG. 7A , the shock wave generator 706 is positioned at the center of the balloon 702. In one or more examples, the catheter 700 can include a side tube (similar to the side tube 430 of FIG. 4A ) that extends to the apex of the crescent (e.g., outward from the center of the balloon) and includes additional shock wave generators. Thus, the catheter 700 can include shock wave generators 706 distributed throughout the balloon 702, rather than being located only at the center of the balloon 702 surrounding the elongated tube 704.

[0088] When generating shock waves from the shock wave generator 706, the shock waves can propagate generally outward. In one or more examples, the shock wave generator 706 can be oriented to propagate shock waves generally upward with respect to the view shown in Figure 7B (as indicated by arrow 707 in Figure 7B). Alternatively, or in addition, the shock wave generator 706 can be oriented to generate shock waves in various directions outward from the elongated tube 704.

[0089] Balloon 702 can be configured and / or shaped (e.g., ribs, struts, scaffolding, springs, shape memory material, etc.) to assume a double crescent shape when inflated, based on manufacturing steps during the balloon-forming process. Balloon 702 can include internal structural features that ensure balloon 702 assumes a double crescent shape when inflated. For example, balloon 702 can include an inner wall 711 that ensures balloon 702 assumes a double crescent shape when inflated. Inner wall 711 can be a feature included in balloon 702 during the balloon-forming process. When deflated, balloon 702 can be positioned closely adjacent to elongated tube 704, which improves maneuverability of catheter 700. When inflated, the double crescent shape of balloon 702 leaves opening 717, which provides a channel that allows blood to flow through body cavity 715 and past catheter 700 when balloon 702 is inflated.

[0090] The flow rate of blood flowing through the channels (i.e., openings 717) of the catheter 700 when the balloon 702 is fully inflated can be approximately 50% of the flow rate of blood that normally flows through a body cavity when the catheter 700 is not disposed within the body cavity (i.e., the "normal flow rate"). In one or more examples, the flow rate of blood flowing through the channels of the balloon 702 can be less than 50% of the normal flow rate, such as 10%, 15%, 20%, or 25% of the normal flow rate. In one or more examples, the flow rate of blood flowing through the channels of the balloon 702 can be greater than 50% of the normal flow rate, such as 70%, 80%, or 90% of the normal flow rate. The balloon 702 can be configured to contact the body cavity and / or occluded areas of the body cavity when fully inflated. Alternatively, the balloon 702 can be configured to expand only a specified amount when fully inflated (e.g., expand 50% in diameter relative to its uninflated diameter).

[0091] 7B, balloon 702 contacts only a portion (e.g., an upper portion) of the wall of body cavity 715. In use, a surgeon may treat each portion of body cavity 715 sequentially by rotating balloon 702 within body cavity 715, for example, by rotating elongated tube 704, to contact new portions of the wall of body cavity 715. For example, a surgeon may rotate elongated tube 704 clockwise in incremental steps to treat the entire body cavity 715. Beneficially, to treat the entire body cavity 715 using catheter 700, a surgeon does not need to deflate and re-inflate balloon 702, as may be necessary when relying on a balloon that does not include a channel that allows blood to flow past the catheter during the procedure.

[0092] Although the electrode assemblies and catheter devices described herein have been discussed in the context of treating vascular lesions, primarily coronary artery occlusions, the electrode assemblies and catheters herein can be used for a variety of occlusions, such as occlusions in the peripheral vasculature (e.g., above the knee, below the knee, iliac, carotid, etc.). As a further example, similar designs can be used for soft tissue treatments, such as removal of cancer and tumors (i.e., non-thermal ablation methods), thrombi, fibroids, cysts, organs, scars, and fibrous tissue, or other tissue destruction and removal. The electrode assembly and catheter designs can also be used for nerve stimulation treatments, targeted drug delivery, treatment of tumors within body cavities (e.g., tumors in blood vessels, the esophagus, the intestine, the stomach, or the vagina), wound treatment, non-surgical removal and destruction of tissue, or in place of thermal treatments or cauterization for venous insufficiency and fallopian tube ligation (i.e., permanent female contraception).

[0093] In one or more examples, the electrode assemblies and catheters described herein can also be used in tissue engineering methods, such as mechanical tissue decellularization to generate bioactive scaffolds in which new cells (e.g., exogenous or endogenous cells) can replace old cells; introducing porosity into a site to improve cell retention, cell infiltration / migration, and the diffusion of nutrients and signaling molecules to promote angiogenesis, cell proliferation, and tissue regeneration, as well as cell replacement therapy. Such tissue engineering methods can be useful for treating ischemic heart disease, fibrotic liver, fibrotic intestine, and traumatic spinal cord injury (SCI). For example, for the treatment of spinal cord injury, the devices and assemblies described herein can facilitate the removal of scarred spinal cord tissue, which acts as a barrier to neuronal reconnection, prior to the injection of a lentivirus-loaded anti-inflammatory hydrogel to genetically engineer spinal cord neurons to regenerate.

[0094] The elements and features of the exemplary electrode assemblies and catheters discussed above may be rearranged, recombined, and modified without departing from the present invention. Furthermore, numerical designations such as "first," "second," "third," and "fourth" are merely descriptive and do not indicate the relative order, location, or identity of the elements or features described by these designations. For example, a "first" shockwave may be immediately followed by a "third" shockwave, which in turn may be followed by a "second" shockwave. As another example, a "third" emitter may be used to generate a "first" shockwave, and vice versa. Thus, the numerical designations of various elements and features are not intended to limit the present disclosure and may be modified and interchanged without departing from the present invention.

[0095] It should be noted that the elements and features of the exemplary catheters illustrated throughout this specification and drawings may be rearranged, recombined, and modified without departing from the present invention. For example, while this specification and drawings describe and illustrate catheters with several exemplary balloon designs, the present disclosure is intended to include catheters with various balloon configurations. The number, placement, and spacing of electrode pairs on the shockwave generator may be modified without departing from the present invention. Additionally, the number, placement, and spacing of balloons on the catheter may be modified without departing from the present invention.

[0096] The foregoing is merely illustrative of the principles of the present invention, and it should be understood that various modifications, variations, and combinations can be made by those skilled in the art without departing from the scope and spirit of the invention. Any of the various catheter variations disclosed herein may include features described with any other catheter or combination of catheters herein. Furthermore, any method may be used with any of the disclosed catheters. Accordingly, the present invention is not intended to be limited except as by the appended claims.

Claims

1. A catheter for treating a stricture in a body cavity, the catheter comprising: A long thin tube, at least one shock wave generator comprising at least one electrode pair; at least one balloon sealed to the distal end of the elongated tube and surrounding the at least one shock wave generator, the at least one balloon being capable of being filled with a conductive fluid; at least one channel that allows blood to flow through the body cavity and past the at least one balloon while the at least one balloon is inflated; A catheter comprising:

2. 10. The catheter of claim 1, wherein the at least one channel allows blood to flow through the body cavity at a rate that is at least 50% of a normal flow rate of blood through the body cavity when the catheter is not positioned within the body cavity.

3. The catheter of claim 1 , wherein the at least one channel is defined by at least one lumen extending exteriorly of the elongate tube.

4. The catheter of claim 3 , wherein the at least one lumen extends outside an outer surface of the at least one balloon.

5. The catheter of claim 1 , wherein the at least one channel extends within the elongate tube.

6. 6. The catheter of claim 5, wherein the elongated tube comprises at least one opening to the at least one channel, the opening being located proximal to the at least one balloon for allowing blood to flow in or out of the at least one channel, and at least one opening from the at least one channel to the at least one channel, the opening being located distal to the at least one balloon for allowing blood to flow in or out of the at least one channel.

7. 2. The catheter of claim 1, wherein the catheter comprises a plurality of balloons and a plurality of shock wave generators, each balloon of the plurality of balloons sealed to a region of the elongate tube and surrounding one or more of the plurality of shock wave generators, and the at least one channel is defined by spacing between the plurality of balloons.

8. The catheter of claim 7 , wherein the plurality of balloons is at least three balloons.

9. The catheter of claim 8 , wherein a cross section of each of the at least three balloons comprises a circular shape.

10. The catheter of claim 1 , wherein a cross section of each of the at least three balloons comprises an elliptical shape.

11. 10. The catheter of claim 1, wherein the at least one balloon comprises a plurality of lobes extending outwardly from the elongate tube, and the at least one channel is defined by spacing between the plurality of lobes of the at least one balloon.

12. 10. The catheter of claim 1, wherein the at least one balloon comprises a crescent shape when inflated, and the at least one channel is defined by a space between the at least one balloon and the body cavity.

13. 10. The catheter of claim 1, wherein the at least one balloon comprises a double crescent shape when inflated, and the at least one channel is defined by a space between the at least one balloon and the body cavity.

14. The catheter of claim 1 , wherein the elongate tube includes a guidewire lumen for receiving a guidewire, the catheter being configured to be advanced into the body lumen over the guidewire.

15. 1. A system for treating a stricture in a body cavity, the system comprising: A catheter comprising: A long thin tube, at least one shock wave generator comprising at least one electrode pair; at least one balloon sealed to the distal end of the elongated tube and surrounding the at least one shock wave generator, the at least one balloon being capable of being filled with a conductive fluid; at least one channel that allows blood to flow through the body cavity and past the at least one balloon while the at least one balloon is inflated; a catheter comprising: a power source configured to apply voltage pulses to the at least one shock wave generator to generate shock waves for treating the stenosis; A system comprising:

16. 16. The system of claim 15, wherein the at least one channel allows blood to flow through the body cavity at a rate that is at least 50% of a normal flow rate of blood through the body cavity when the catheter is not positioned within the body cavity.

17. The system of claim 15 , wherein the at least one channel is defined by at least one lumen extending exteriorly of the elongate tube.

18. 18. The system of claim 17, wherein the at least one lumen extends outside an outer surface of the at least one balloon.

19. The system of claim 15 , wherein the at least one channel extends within the elongate tube.

20. 20. The system of claim 19, wherein the elongated tube comprises at least one opening to the at least one channel, the at least one opening being located proximal to the at least one balloon for allowing blood to flow in or out of the at least one channel, and at least one opening from the at least one channel to the at least one channel, the at least one opening being located distal to the at least one balloon for allowing blood to flow in or out of the at least one channel.

21. 16. The system of claim 15, wherein the catheter comprises a plurality of balloons and a plurality of shock wave generators, each balloon of the plurality of balloons sealed to a region of the elongate tube and surrounding one or more of the plurality of shock wave generators, and the at least one channel extending between the plurality of balloons.

22. 22. The system of claim 21, wherein the plurality of balloons is at least three balloons.

23. 23. The system of claim 22, wherein a cross section of each of the at least three balloons comprises a circular shape.

24. 23. The system of claim 22, wherein a cross section of each of the at least three balloons comprises a circular shape.

25. 16. The system of claim 15, wherein the at least one balloon comprises a plurality of lobes extending outwardly from the elongate tube, and the at least one channel is defined by spacing between the plurality of lobes of the at least one balloon.

26. 16. The system of claim 15, wherein the at least one balloon comprises a crescent shape when inflated, and the at least one channel is defined by spacing between the plurality of lobes of the at least one balloon.

27. 16. The system of claim 15, wherein the at least one balloon comprises a double crescent shape when inflated, and the at least one channel is defined by spacing between the plurality of lobes of the at least one balloon.

28. 16. The system of claim 15, wherein the elongate tube includes a guidewire lumen for receiving a guidewire, and the catheter is configured to be advanced over the guidewire into the body cavity.

29. 1. A method for treating a stricture in a body cavity, the method comprising: advancing a catheter within the body cavity to a location adjacent the stenosis; inflating at least one balloon of the catheter, wherein an outer surface of the at least one balloon contacts the body cavity while the at least one balloon is inflated, and blood is allowed to flow through the body cavity past the at least one balloon; generating shock waves via at least one shock wave generator on said catheter while blood flows through said body cavity past said at least one balloon; A method comprising:

30. 30. The method of claim 29, comprising advancing a guidewire within the body lumen to locate the stenosis, and advancing the catheter over the guidewire.

31. 31. The method of claim 30, comprising retracting the guidewire before inflating the balloon.

32. 32. The method of claim 31, comprising retracting the guidewire so that a distal end of the guidewire is located proximal to the proximal end of the balloon.

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