A system for treating blood clots in body tubal lumen

Abstract

To provide a favorable system for treating a thrombus in a body lumen.SOLUTION: The present disclosure relates generally to thrombectomy devices. An exemplary catheter comprises: an emitter assembly comprising at least one emitter; where each emitter comprises an electrode pair, and where each emitter is configured to generate a plurality of cavitation bubbles when a voltage is applied to the pair of electrodes; an infusion lumen formed by at least a portion of an outer wall of the catheter, the infusion lumen configured to receive a conductive fluid, where the emitter assembly is housed in the infusion lumen, where a distal segment of the infusion lumen includes a plurality of holes on the portion of the outer wall of the catheter, and where the holes are configured to release the conductive fluid and the cavitation bubbles out of the catheter to treat a thrombus at a treatment site; and an aspiration lumen including aspiration ports at the distal segment thereof.SELECTED DRAWING: Figure 2A

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims priority to U.S. Provisional Patent Application No. 62 / 904,974, filed on September 24, 2019, entitled "SYSTEM FOR TREATING THROMBUS IN BODY LUMENS", the content of which is incorporated herein by reference in its entirety. (Field of Disclosure)

[0002] This disclosure generally relates to thrombus removal devices, and more specifically to thrombus removal devices designed to generate cavitation bubbles for reducing or removing thrombus from a patient's vasculature.

Background Art

[0003] Thrombus removal devices are designed to reduce the clot burden and partially or completely remove blood clots (i.e., thrombi) from a patient's vasculature. Currently, the mechanisms for removing thrombi in most thrombus removal devices are mechanical or involve a combination of plasminogen activator ("tPA") therapy and mechanical processes. Some of these devices use ultrasound for the purpose of diffusing tissue plasminogen activator (tPA). It does this by increasing the permeability of the thrombus structure, and increasing the permeability of the thrombus structure exposes more sites to which thrombolytic agents can bind. All of these devices have drawbacks because they provide an undesirably slow rate of clot removal (which typically requires an overnight hospital stay). Additionally, these devices are expensive, bulky, and tend to be difficult to operate. Still further, these devices can be associated with high blood loss in patients.

[0004] Therefore, there is a need for a device that treats blood clots without the use of drugs (e.g., tPA) and provides a cost - effective and time - efficient solution for treating thrombi. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The present invention relates to a thrombectomy device designed to generate cavitation bubbles for reducing or removing blood clots from a patient's vascular system. Embodiments of the present invention do not require the use of drugs (e.g., tPA) and can work rapidly (e.g., in less than 2 hours), thus providing a cost-effective and efficient solution for treating blood clots. [Means for solving the problem]

[0006] In one embodiment, the present invention provides a device for generating cavitation bubbles. An exemplary catheter comprises an emitter assembly having at least one emitter, each emitter comprising a pair of electrodes, each emitter configured to generate a plurality of cavitation bubbles when a voltage is applied to the pair of electrodes; an injection lumen formed by at least a portion of the outer wall of the catheter, the injection lumen configured to receive a conductive fluid, the emitter assembly is housed within the injection lumen, the distal segment of the injection lumen includes a plurality of holes on the portion of the outer wall of the catheter, the plurality of holes configured to release a conductive fluid and a plurality of cavitation bubbles out of the catheter to treat a thrombus at the treatment site; and a suction lumen formed within the catheter and including a plurality of suction ports in its distal segment.

[0007] In some embodiments, the emitter assembly comprises an elongated conductive tube and an insulating wire having a helical coiled portion at the end of the insulating wire, the coiled portion including an exposed tip, the coiled portion being located within the elongated conductive tube, and configured such that when a voltage is applied across the insulating wire and the elongated conductive tube, a current flows from the exposed distal tip of the insulating wire to the elongated conductive tube, generating a plurality of cavitation bubbles.

[0008] In some embodiments, the elongated conductive tube is provided with a slot, and the current is configured to flow from the exposed distal end of an insulated wire to the edge of the slot.

[0009] In some embodiments, the current is configured to flow from the exposed distal end of an insulated wire to the inner wall of an elongated conductive tube.

[0010] In some embodiments, the emitter assembly comprises a first wire and a second wire, wherein at least a portion of the insulator is removed from a portion of the first wire and at least a portion of the insulator is removed from a portion of the second wire, and the portions of the first wire and the portions of the second wire are arranged alternately, and when a voltage is applied across the first and second wires, a current flows from the first wire to the second wire, generating a plurality of cavitation bubbles.

[0011] In some embodiments, the emitter assembly comprises a conductive sheath and an insulated wire having an exposed tip, wherein current flows from the exposed distal tip of the insulated wire to the conductive sheath, generating a plurality of cavitation bubbles.

[0012] In some embodiments, the multiple holes are arranged in three rows spaced 120 degrees apart on the outer wall of the catheter.

[0013] In some embodiments, the injection lumen is Y-shaped.

[0014] In some embodiments, the pump is configured to deliver a continuous flow of conductive fluid to the emitter assembly through an injection lumen.

[0015] In some embodiments, continuous flow of a conductive fluid washes away debris into the suction lumen through multiple suction ports.

[0016] In some embodiments, the pump is configured to apply suction force at the proximal end of the suction lumen, drawing the debris into the suction lumen through multiple suction ports.

[0017] In some embodiments, the suction ports of the multiple suction ports are larger than the holes of the multiple holes.

[0018] In some embodiments, the catheter further comprises a guidewire lumen for housing a guidewire.

[0019] In some embodiments, the catheter further comprises a distal cap configured to seal the distal end of the catheter, the distal cap having a hole for housing a guidewire.

[0020] In some embodiments, the catheter further comprises an electrical wire lumen for housing one or more wires of the emitter assembly.

[0021] In some embodiments, the voltage is 500V to 1,200V.

[0022] In some embodiments, the repetition rate of the applied voltage is adjustable from 25Hz to 200Hz.

[0023] In some embodiments, the electrode pair has a spark gap between the paired electrodes, and the spark gap is less than 0.005 inches. This specification also provides, for example, the following items: (Item 1) A catheter, wherein the catheter is An emitter assembly having at least one emitter, Each emitter is equipped with an electrode pair, Each emitter is configured to generate a plurality of cavitation bubbles when a voltage pulse is applied to the pair of electrodes. The emitter assembly, An injection lumen formed by at least a portion of the outer wall of the catheter, wherein the injection lumen is configured to receive a conductive fluid, The emitter assembly is housed within the injection lumen, The distal segment of the injection lumen includes a plurality of holes on the portion of the outer wall of the catheter. The plurality of holes are configured to release the conductive fluid and the plurality of cavitation bubbles from the catheter to treat the thrombus at the treatment site. The injection lumen and The suction tube lumen formed within the catheter Equipped with, A catheter wherein the suction lumen includes a plurality of suction ports in its distal segment. (Item 2) The emitter assembly is A long, slender conductive tube, Insulated wire and Equipped with, The aforementioned insulating wire has a helical coil-shaped portion at its end, The aforementioned coiled portion includes the exposed tip, The coiled portion is located inside the elongated conductive tube. The catheter according to item 1, wherein when a pulsed voltage is applied across the insulating wire and the elongated conductive tube, a current flows from the exposed distal end of the insulating wire to the elongated conductive tube, generating the plurality of cavitation bubbles. (Item 3) The catheter according to item 2, wherein the elongated conductive tube is provided with a slot, and the current is configured to flow from the exposed distal end of the insulating wire to the edge of the slot. (Item 4) The catheter according to item 2, wherein the current is configured to flow from the exposed distal end of the insulated wire to the inner wall of the elongated conductive tube. (Item 5) The emitter assembly comprises a first wire and a second wire, At least a portion of the insulator is removed from the portion of the first wire, defining one electrode of the pair of electrodes, At least a portion of the insulator is removed from a portion of the second wire, defining the second electrode of the pair of electrodes, The first wire portion is arranged alternately with the second wire portion, The catheter according to item 1, wherein when a pulsed voltage is applied across the first wire and the second wire, a current flows from the first wire to the second wire, generating the plurality of cavitation bubbles. (Item 6) The emitter assembly is Conductive sheath, An insulated wire with an exposed tip and Equipped with, The catheter according to item 1, configured such that an electric current flows from the exposed distal end of the insulated wire to the conductive sheath, generating the plurality of cavitation bubbles. (Item 7) The catheter according to item 1, wherein the plurality of holes are arranged in three rows spaced 120 degrees apart on the outer wall of the catheter. (Item 8) The catheter described in item 1, wherein the injection lumen is Y-shaped. (Item 9) The catheter according to item 1, wherein the pump is configured to deliver a continuous flow of conductive fluid through the injection lumen to the emitter assembly. (Item 10) The catheter according to item 9, wherein the conductive fluid comprises physiological saline. (Item 11) The catheter according to item 9, wherein the continuous flow of the conductive fluid washes the debris into the suction lumen through the plurality of suction ports. (Item 12) The catheter according to item 1, wherein the pump is configured to apply suction force at the proximal end of the suction lumen and to draw fragments into the suction lumen through the plurality of suction ports. (Item 13) The catheter described in item 1, wherein the suction ports of the plurality of suction ports are larger than the holes of the plurality of holes. (Item 14) The catheter described in item 1, further comprising a guidewire lumen for housing a guidewire. (Item 15) The catheter according to item 14, further comprising a distal cap configured to seal the distal end of the catheter, the distal cap having a hole for accommodating the guidewire. (Item 16) The catheter according to item 1, further comprising an electrical wire lumen for housing one or more wires of the emitter assembly. (Item 17) The catheter described in item 1, wherein the voltage of the applied voltage pulse is 500V to 1,200V. (Item 18) The catheter described in item 1, wherein the repetition rate of the applied voltage pulse is adjustable from 25 Hz to 200 Hz. (Item 19) The electrode pair comprises a spark gap between the electrodes of the pair, wherein the spark gap is less than 0.005 inches, as described in item 1. [Brief explanation of the drawing]

[0024] [Figure 1] Figure 1A depicts exemplary emitter assemblies according to several embodiments. Figure 1B depicts exemplary emitter assemblies according to several embodiments.

[0025] [Figure 2A] Figure 2A depicts a cross-sectional view of an exemplary catheter housing an emitter assembly according to several embodiments.

[0026] [Figure 2B] Figure 2B depicts another exemplary catheter housing an emitter assembly according to several embodiments.

[0027] [Figure 3] Figure 3 depicts another exemplary emitter assembly according to several embodiments.

[0028] [Figure 4] Figure 4 depicts another exemplary emitter assembly according to several embodiments. [Modes for carrying out the invention]

[0029] The following description is provided to enable those skilled in the art to fabricate and use various embodiments. 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 defined 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 given a scope consistent with the claims.

[0030] Described herein are exemplary systems and methods for reducing or removing thrombi from a patient's vascular system by generating cavitation bubbles via a voltage source. According to some embodiments, the treatment system includes a catheter and one or more emitters housed within the catheter. The catheter is advanced (e.g., via a guidewire) within a body lumen (e.g., a blood vessel) to the treatment site. Each emitter includes an electrode, which, when connected to a generator with a relatively low voltage and a high PRF (pulse repetition rate), forms a plasma arc, which then leads to the generation and collapse of a large number of cavitation bubbles. In some embodiments, the catheter has one or more rows of cavitation holes for releasing cavitation bubbles in an omnidirectional manner. The cavitation bubbles create mechanical vibration, turbulence, jets, and / or forceful collapses, weakening and destroying the fibrin fibrous network and thus reducing and removing thrombi.

[0031] This invention differs from electrohydraulic lithotripsy. The voltage at each emitter (i.e., across the spark gap) is lower than that of intravascular lithotripsy ("IVL") treatment. In some embodiments, the generator voltage is regulated between 500V and 1,200V, and the repetition rate is regulated between 25Hz and 200Hz. To maintain the breakdown voltage, the spark gap at the emitter (e.g., the spark gap formed between the two electrodes of an electrode pair) is small enough to allow sparking. In some embodiments, the gap is less than 0.005 inches. Furthermore, the energy delivered is lower than that of IVL, and therefore the acoustic power is usually not sufficient to generate a pressure amplitude from any shock wave.

[0032] Figure 1A depicts an exemplary emitter assembly 100 according to several embodiments. The emitter assembly 100 comprises two conductive elongated tubes 110 and 112. Each elongated tube has multiple longitudinal slots to facilitate the generation of cavitation bubbles, as discussed below. Furthermore, the emitter assembly 100 comprises three wires 102, 104, and 106. In some examples, the elongated tubes may be stainless steel hypo tubing, and the wires may be polyimide insulated copper wires.

[0033] The first insulating wire 102 has a helical coil portion at its distal end and is installed inside the first elongated tube 110. In some embodiments, the helical coil portion is joined to the inner wall of the elongated tube 110 using an adhesive (e.g., epoxy or cyanoacrylate adhesive). Similarly, the second insulating wire 104 has a helical coil portion at its distal end and is installed inside the second elongated tube 112. The third insulating wire 106 has a distal end connected (e.g., welded) to the second elongated tube 112. Furthermore, the proximal end of the second insulating wire 104 is connected (e.g., welded) to the first elongated tube 110.

[0034] When the emitter assembly 100 is connected to a voltage source, current traverses through the two elongated tubes and three wires, generating cavitation bubbles at two locations. Referring to Figure 1A, the proximal end of the first wire 102 is connected to the positive port of the voltage generator (not depicted), and the proximal end of the third wire 106 is connected to the negative portion of the voltage generator. The generator delivers energy in a continuous pulse mode or a series of short bursts. Thus, current i traverses the emitter assembly as indicated by the arrow. As shown, current i traverses from the proximal end of the first insulated wire 102 toward its distal coiled portion. At the distal end of the first insulated wire 102, the conductive core of the wire is exposed, thus allowing current to traverse from the distal end of the wire 102 to the first elongated tube 110. The exposed distal end of the first wire 102 and the first elongated tube 110 form a first electrode pair for generating cavitation bubbles.

[0035] The current i traverses from the first elongated tube 110 to the proximal end of the second insulated wire 104, and then further to the distal coiled portion of the second insulated wire 104. At the distal end of the second insulated wire 104, the conductive core of the wire is exposed, thus allowing the current to traverse from the distal end of the wire 104 to the second elongated tube 112. The exposed distal end of the second wire 104 and the second elongated tube 112 form a second electrode pair for generating cavitation bubbles. The current i then returns to the voltage generator via the third insulated wire 106.

[0036] When current i traverses from the distal coiled portion of the wire to the elongated tube enclosing the coiled portion, multiple plasma arcs are formed between the exposed distal end of the wire and the inner surface of the elongated tube. The plasma arcs lead to cavitation bubbles in a controlled manner (one at a time, at a specific rate), which then lead to mechanical vibrations and other bubble dynamics-related effects in the conductive fluid, such as collapse, turbulence, and jetting (e.g., via bubble expansion and collapse). Mechanical vibrations play a role in reducing or removing thrombi. Cavitation is known to weaken the fibrin network bridges, which are the basic structure of thrombi. The combination of mechanical vibrations and bubble cavitation may be effective in thrombolysis. Compared to the generators used in the conventional shock wave generation systems mentioned above, the generator for the system is configured to generate lower voltage pulses at a higher pulse repetition rate in order to minimize the intensity of any shock wave and optimize and maximize bubble growth and collapse. For example, in a conventional system, each pulse may be approximately 3,000 volts with a repetition rate of 1 Hz. In embodiments of the system, the voltage of the voltage pulse is adjusted between 500 V and 1,200 V, the repetition rate of the voltage pulse is adjusted between 25 Hz and 200 Hz, and the pulse duty cycle is adjusted between 10 and 50%. These parameters can be varied based on blood clot conditions.

[0037] Figure 1B depicts exemplary emitter assembly 100 from different angles showing the distal coiled portions of two wires according to several embodiments. As the plasma arc causes erosion of the electrodes during operation, the helical coiled portions of wires 102 and 104 may be eroded and shortened over time. Depending on the location of the distal ends of the wires, the spark gap (i.e., where the plasma arc is formed) may be between the distal end of the wire and the inner wall of the elongated tube (as shown in detail in Figure A) or between the distal end of the wire and the edge of the slot in the elongated tube (as shown in detail in Figure B). Note that as the coiled wire portions are eroded, the location of cavitation bubble generation will change. In the illustrated embodiments, the location of cavitation bubble generation will rotate circumferentially near the periphery of the conductive tubes 110 and 112.

[0038] Further details relating to electrode pairs formed by coiled wires and elongated tubes, along with possible modifications, are provided in the assignee's prior application, U.S. Publication No. 2019 / 0388110 (incorporated by reference), entitled “SYSTEM FOR TREATING OCCLUSIONS IN BODY LUMENS.” Figures 1A–B depict an emitter assembly comprising two emitters connected in series and driven by a single voltage source; however, it should be understood that the emitter assembly may comprise any number of emitters arranged in any configuration driven by one or more voltage sources.

[0039] Figure 2A depicts a cross-sectional view of an exemplary catheter 200 having several lumens according to several embodiments. The catheter 200 comprises a Y-shaped injection lumen 210 and three oval lumens, namely a guidewire lumen 204, an electrical wire lumen 206, and a suction lumen 208. As shown in Figure 2A, the oval lumens 204, 206, and 208 are spaced approximately 120 degrees apart along the outer wall of the catheter and are formed at least partially from the outer wall of the catheter. The inner edges of the guidewire lumen 204, the electrical wire lumen 206, and the suction lumen 208 define the outer edge of the central Y-shaped injection lumen 206.

[0040] The Y-shaped injection lumen 210 houses an emitter assembly 202, which may be one of the emitter assemblies described herein (e.g., 100, 300, 400). As discussed above, the emitter assembly 202 comprises several elongated conductive tubes and wires, forming several emitters (or electrode pairs). In some embodiments, the emitter assembly 202 is installed in the distal segment of the catheter.

[0041] The Y-shaped injection lumen 210 can be further used to deliver an ionic solution (e.g., a conductive solution such as saline or saline mixed with a contrast agent) from the pump to the emitter assembly 202. When the emitter assembly 202 is connected to a voltage source, cavitation bubbles can be generated at multiple locations along the catheter via the conductive fluid.

[0042] The Y-shaped injection lumen further comprises multiple rows of cavitation holes for releasing cavitation bubbles. In the example depicted, three rows of cavitation holes 212a, 212b, and 212c are spaced 120 degrees apart. As shown in Figure 2A, the cavitation holes 212a, 212b, and 212c may include multiple lateral holes extending along a portion of the circumference of the distal end of the catheter. The cavitation holes are positioned to maximize the release of cavitation bubbles and may be located, for example, directly above the first elongated tube, the second elongated tube, or another element of the emitter assembly. Thus, cavitation bubbles from the emitter assembly are carried radially through the rows of cavitation holes to the thrombus by the pressurized flow of the ionic solution.

[0043] The suction lumen 208 can be used to remove debris (e.g., metal, air bubbles) and thrombus fragments from the treatment site. As shown, the suction lumen 208 is equipped with a series of suction ports 214. The suction ports 214 are generally larger than the cavitation holes 212. As more conductive fluid is injected, the debris and thrombus fragments are flushed towards the suction lumen and carried away from the treatment site. In addition, or alternatively, suction force can be provided at the proximal end of the suction lumen 208. The debris and thrombus fragments can be drawn into the suction ports 214 and carried away from the treatment site via the flow of conductive fluid. Rapid removal of debris helps to refresh the cavitation.

[0044] The electrical wire lumen 206 can be used to house one or more wires of the emitter assembly 202. For example, a wire (e.g., wire 106) connecting the distal portion of the emitter assembly to the negative port of the voltage generator may extend through the electrical wire lumen 206 for better insulation. The wire lumen 206 may also carry one or more additional wires, for example, a wire 102 connecting the proximal portion of the emitter assembly to the positive port of the voltage generator. The guidewire lumen 204 can be used to house a guidewire and may be molded to carry a guidewire having a diameter of approximately 0.014 inches to approximately 0.035 inches. The guidewire is used to advance the catheter 200 to the treatment site.

[0045] Figure 2B depicts another exemplary catheter housing an emitter assembly according to several embodiments. As shown, the catheter includes a cap 230 which includes a guidewire port for receiving a guidewire (e.g., a guidewire carried within the guidewire lumen of the catheter during catheter advancement). Furthermore, the shape and location of the suction port and cavitation holes differ from those in the embodiments illustrated in Figure 2A. For example, as shown in Figure 2B, the suction port may be formed as a longitudinal slot sized to allow debris from cavitation to escape through the suction port. The cavitation port may include a plurality of substantially circular holes within the catheter housing (i.e., the outer wall of the catheter) to allow access to a Y-shaped injection lumen.

[0046] The catheter shown in Figure 2A-B can be used in conjunction with a pump. In some embodiments, the pump delivers an ionic solution (i.e., a conductive solution such as saline or saline mixed with a contrast agent) through the injection lumen to the catheter tip (where cavitation occurs). The pump or auxiliary pump also performs suction to move the fragment away from the thrombus area. The injection flow can be synchronized with the power delivery of the emitter to ensure adequate ionic solution around the emitter. The suction flow and injection flow can be synchronized to maintain pressure equilibrium at the treatment site. In some examples, the flow of saline or saline / contrast agent is adjusted to avoid overheating problems and control treatment efficiency and rate.

[0047] In some embodiments, additional components are included in the treatment system, such as a proximal balloon for capturing debris generated by the emitter, a visualization system and / or a steering system (e.g., a side branch) for properly navigating and positioning the catheter. Further details of the treatment system are provided in U.S. Publication No. 2019 / 0388110 (referenced above and incorporated herein by reference).

[0048] In some embodiments, the procedure may take approximately 30 minutes, during which time the emitter assembly 202 continuously generates cavitation bubbles. These operating parameters (e.g., voltage of the voltage pulse, repetition rate, or pulse duty cycle) can be set based on the characteristics of the blood clot (e.g., size of the blood clot, age of the blood clot, composition of the blood clot, flexibility of the blood clot, arterial or venous location of the blood clot, platelet content of the blood clot, fibrin content of the blood clot, or other attributes of the blood clot) and / or the characteristics of the patient (e.g., age of the patient or pre-existing medical conditions). In some embodiments, after the procedure, postoperative minimally invasive procedures (e.g., treatment of bleeding, thrombus reformation) can be performed.

[0049] Figure 3 depicts another exemplary emitter assembly housed within the catheter 300 according to several embodiments. The emitter assembly includes four wires 302, 304, 306, and 308. Each of the four wires includes a portion that is spirally wound around a shaft 320 (e.g., a guidewire shaft having a lumen for carrying a guidewire), and together the four wires form three alternating wire portions. The alternating wire portions may comprise multiple (i.e., two or more) portions of a wire configured in an alternating manner. For example, an alternating wire portion may include a portion of a wire coiled together with a portion of another wire. In some variations, the wire and the alternating wire portions are configured in series. For example, the first wire 302 may be electrically coupled to the positive terminal of a voltage source. The first alternating wire portion may comprise a portion of the first wire 302 alternating with a first portion of a second wire 304. The first wire 302 may have a voltage or potential that is greater than that of the second wire 304. Similarly, the second alternating wire section 304 may comprise the first portion of the third wire 306 and the second portion of the second wire 304, which are alternating. The second wire 304 may have a voltage or potential that is greater than that of the third wire 306. The third alternating wire section 306 may comprise the second portion of the third wire 306 and a portion of the fourth wire 308. The third wire 306 may have a voltage or potential that is greater than that of the fourth wire 308. The fourth wire 308 may be electrically coupled to the negative terminal of the voltage source.

[0050] In the embodiment illustrated in Figure 3, each alternating wire section includes at least one pair of electrodes. Each pair of electrodes is defined by removing a small area of ​​insulator from adjacent sections of the alternating wires. When the wires are surrounded by a conductive fluid (i.e., when the conductive fluid is flowing through the wire lumen), a high voltage is delivered to the wires, causing an electro-hydraulic discharge that generates a plasma that produces cavitation bubbles in the arc-generating region traversing the electrodes. Further details of the operation of the emitter assembly and possible modifications can be found in the assignee's prior application, U.S. Publication No. 2018 / 0098779 (incorporated by reference), entitled "AORTIC LEAFLET REPAIR USING SHOCK WAVE APPLICATORS".

[0051] In the embodiment illustrated in Figure 3, the emitter assembly is housed in a catheter 300, for example, one of the catheters described with respect to Figures 2A-B. As shown, the catheter has a row of cavitation holes (e.g., longitudinal or lateral slots or circular holes) positioned above the emitter to release cavitation bubbles in an omnidirectional manner.

[0052] Figure 4 depicts another exemplary emitter assembly housed within a catheter 400 according to several embodiments. The emitter assembly includes four wires 402, 404, 406, and 408, and three conductive sheaths 410, 412, and 414. The conductive sheaths are wrapped around the entire circumference of a portion of a shaft 420 (e.g., a guidewire shaft having a lumen for carrying a guidewire). The outer electrode is formed by the conductive sheath, and the inner electrode is formed by removing a portion of the insulating wire to expose the conductive portion of the insulating wire (e.g., cutting a hole in the insulating layer near the end of the wire). The inner electrode is positioned at a controlled distance from the side edge of the conductive sheath to allow a reproducible arc with respect to a given current and voltage. During operation, a plasma arc may be formed across the inner electrode and the side edge of the conductive sheath.

[0053] In the embodiment illustrated in Figure 4, the emitter assembly is connected to a voltage source using a first wire 402 and a fourth wire 408, for example, the first wire connected to the positive port and the fourth wire connected to ground at the negative port. Current traverses from the first wire 402 through the first conductive sheath 410, the second wire 404, the second conductive sheath 412, the third wire 406, the third conductive sheath 414, and the fourth wire 408 to the negative port of the voltage source. Thus, the emitter assembly generates cavitation bubbles at six locations (i.e., the two side edges of each conductive sheath where the sheath, together with the insulation-removed portion of the wire, forms an electrode pair). Further details of the operation of the emitter assembly and possible variables can be found in "LOW PROFILE ELECTRODES FOR This can be found in the assignee's prior application, U.S. Publication No. 2019 / 0150960 (incorporated by reference), titled "A SHOCK WAVE CATHETER".

[0054] In the embodiment illustrated in Figure 4, the emitter assembly is housed in a catheter 400, for example, one of the catheters described with respect to Figures 2A-B. As shown, the catheter has a row of cavitation holes (e.g., longitudinal or lateral slots or circular holes) positioned above the emitter to release cavitation bubbles in an omnidirectional manner.

[0055] It should be understood that the foregoing is merely an illustration of the principles of the present invention, and that various modifications, alterations, 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 modifications of the cavitation devices disclosed herein may include features described by any other combination of cavitation or shock wave devices herein. Furthermore, any of the methods may be used in conjunction with any of the cavitation devices disclosed. Thus, the invention is not intended to be limited except as provided by the appended claims. With respect to all of the modifications described above, the steps of the method do not need to be performed sequentially.

Claims

1. A catheter for use in the lumen of the vascular system, wherein the catheter is An emitter assembly comprising at least one emitter, wherein the at least one emitter comprises an elongated conductive tube and a wire, the wire being at least partially disposed within the elongated conductive tube such that the elongated conductive tube and the uninsulated portion of the wire form an electrode pair, and the electrode pair is configured to generate a plurality of cavitation bubbles when a voltage pulse is applied between the electrode pair. An outer wall defining an injection lumen configured to receive a conductive fluid, wherein the outer wall comprises at least one cavitation hole aligned with the elongated conductive tube, and A catheter equipped with [a specific feature / equipment].

2. The catheter according to claim 1, wherein the electrode pair includes a spark gap smaller than 0.13 mm.

3. The catheter according to claim 1, wherein the voltage pulse is delivered at a frequency of 25 Hz to 200 Hz.

4. The catheter according to claim 1, wherein the voltage pulse is 500V to 1,200V.

5. The catheter according to claim 1, further comprising a guidewire lumen sized to carry a guidewire having a diameter of 0.36 mm to 0.89 mm.

6. The catheter according to claim 1, wherein the at least one cavitation pore is aligned circumferentially with respect to the longitudinal axis of the elongated conductive tube.

7. The catheter according to claim 1, wherein the at least one cavitation hole comprises a row of cavitation holes.

8. The catheter according to claim 1, wherein the catheter is configured to be advanced within the lumen to the treatment site via a guidewire, and is connected via the wire to a voltage generator that generates voltage pulses.

9. A catheter for use in the lumen of the vascular system, wherein the catheter is An emitter assembly comprising at least one emitter, wherein the at least one emitter includes a first wire and a second wire, the uninsulated portions of the first wire and the uninsulated portions of the second wire forming an electrode pair, and the electrode pair is configured to generate a plurality of cavitation bubbles when a voltage pulse is applied between the electrode pair, An outer wall defining an injection lumen configured to receive a conductive fluid, wherein the outer wall comprises at least one cavitation hole aligned with the electrode pair, and A catheter equipped with [a specific feature / equipment].

10. The catheter according to claim 9, wherein at least a portion of the first wire is spirally wound around the shaft to form a first coil, a portion of the second wire is spirally wound around the shaft to form a second coil, and the first coil and the second coil are arranged in an alternating configuration.

11. The catheter according to claim 9, wherein the electrode pair includes a spark gap smaller than 0.13 mm.

12. The catheter according to claim 9, wherein the voltage pulse is delivered at a frequency of 25 Hz to 200 Hz.

13. The catheter according to claim 9, wherein the voltage pulse is 500V to 1,200V.

14. The catheter according to claim 9, further comprising a guidewire lumen sized to carry a guidewire having a diameter of 0.36 mm to 0.89 mm.

15. The catheter according to claim 9, wherein the at least one cavitation hole is circumferentially aligned with the electrode pair.

16. The catheter according to claim 9, wherein the at least one cavitation hole comprises a row of cavitation holes.

17. The catheter according to claim 9, wherein the catheter is configured to be advanced within the lumen to the treatment site via a guidewire, and is connected via the first and second wires to a voltage generator that generates voltage pulses.

18. A catheter for use in the lumen of the vascular system, wherein the catheter is An emitter assembly comprising a plurality of emitters configured to generate a plurality of cavitation bubbles when power is supplied to the emitter assembly, An outer wall defining an injection lumen configured to receive a conductive fluid, wherein the outer wall comprises at least one cavitation hole aligned with the plurality of emitters, and A catheter equipped with [a specific feature / equipment].

19. The catheter according to claim 1, wherein the at least one cavitation pore extends through the outer wall and opens into the injection lumen, and the at least one cavitation pore is configured to release the plurality of cavitation bubbles out of the catheter into the treatment area of ​​the lumen of the vascular system.

20. The catheter according to claim 9, wherein the at least one cavitation pore extends through the outer wall and opens into the injection lumen, and the at least one cavitation pore is configured to release the plurality of cavitation bubbles out of the catheter into the treatment area of ​​the lumen of the vascular system.

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