Intravascular lithotripsy

Abstract

The medical device may include an elongate body, a balloon positioned at a distal portion of the elongate body, and one or more pressure wave emitters positioned within the balloon along a central longitudinal axis of the elongate body. The one or more pressure wave emitters may be configured to propagate pressure waves radially outward through a fluid to fragment calcified lesions at a target treatment site. At least one of the one or more pressure wave emitters may comprise an electron emitter including a first electrode and a second electrode. The first electrode and the second electrode may be positioned to define a spark gap between the first electrode and the second electrode, and the second electrode may include a portion of a hypotube.

Description

[Technical Field]

[0001] The present disclosure relates to the treatment of calcified plaque lesions in a patient's vasculature. [Background technology]

[0002] During an intravascular lithotripsy (IVL) procedure, and more specifically, during an electrohydraulic lithotripsy (EHL) procedure, a clinician uses a catheter configured to emit high-energy pressure waves to destroy calcified plaque lesions within a patient's vasculature. Summary of the Invention

[0003] The present disclosure describes systems and techniques for generating and directing high-energy intravascular pressure waves for the fragmentation and / or disruption of calcified lesions within a patient's vasculature. For illustrative purposes, the techniques herein are described primarily with respect to electrical-based systems and their respective applications, such as peripheral vascular applications. However, it should be understood that the techniques described herein may be assumed to be equally applicable to similar systems based on other forms of energy, such as optical (e.g., laser)-based systems, and their respective applications, such as coronary artery treatment applications, except as expressly stated below.

[0004] Generally, the systems described herein include an energy generator removably coupled to a catheter having an array of pressure wave emitters dispersed within an interventional balloon. During a lesion disruption procedure, a clinician may advance the interventional balloon to a target treatment site within a patient's vasculature and inflate the balloon with an inflation fluid, such as a saline / contrast fluid mixture, until the balloon contacts at least a portion of the local vessel wall. The clinician then activates the energy generator, causing the catheter to generate cavitation bubbles within the fluid-filled balloon and propagate high-energy pressure waves through the balloon and the calcified lesion. Secondary pressure waves may also result from the subsequent collapse of the fluid cavitation, further destabilizing the internal structure of the lesion.

[0005] In some examples, a medical device includes an elongate body; a balloon positioned at a distal portion of the elongate body, the balloon configured to receive a fluid and thereby expand such that an outer surface of the balloon contacts an inner surface of a target treatment site within the patient's vasculature; and one or more pressure wave emitters positioned along a central longitudinal axis of the elongate body within the balloon, the one or more pressure wave emitters configured to propagate pressure waves radially outward through the fluid to fragment calcified lesions at the target treatment site, at least one of the one or more pressure wave emitters including an electron emitter including a first electrode and a second electrode, the first electrode and the second electrode being positioned to define a spark gap between the first electrode and the second electrode, the second electrode including a portion of a hypotube.

[0006] In some examples, the first electrode and the second electrode are embedded in the adhesive layer, and the electron emitter further includes an elastomeric tube radially disposed between the elongated body and the second electrode, hi some examples, the electron emitter further includes a coil layer radially disposed between the elongated body and the elastomeric tube.

[0007] In some examples, the first electrode is oriented such that an outer surface is non-parallel to the central longitudinal axis of the elongate body in the absence of an external force. In some examples, the first electrode is configured to move relative to the elongate body during insertion and removal of the medical device through a patient's vasculature such that the outer surface of the first electrode is oriented parallel to the central longitudinal axis.

[0008] In some examples, the spark gap includes a first spark gap, and the electron emitter further includes a third electrode, the third electrode positioned to define a second spark gap between the second electrode and the third electrode. In some examples, the first electrode, the second electrode, and the third electrode are all part of a common cylindrical surface of the hypotube. In some examples, the first electrode and the third electrode both define a rounded triangular shape, and the second electrode defines a parallelogram shape. In some examples, the first electrode, the second electrode, and the third electrode all define a parallelogram shape.

[0009] In some examples, the first electrode, the second electrode, and the third electrode all define a rounded rectangular shape. In some examples, the first electrode and the third electrode both define an elliptical shape, and the second electrode defines a semi-cylindrical shape. In some examples, the electron emitter further includes a coupler layer positioned radially between the elongated body and the second electrode. In some examples, the coupler layer includes polyimide.

[0010] In some examples, the electron emitter is wired such that the first electrode and the third electrode are independently operable. In some examples, the first electrode is ring-shaped, the second electrode is disk-shaped, and the first electrode is positioned around the second electrode.

[0011] In some examples, the electron emitter further includes a third electrode and a fourth electrode, wherein the third electrode is ring-shaped and the fourth electrode is disk-shaped, the third electrode is positioned around the fourth electrode, and the first, second, third, and fourth electrodes are all part of a common cylindrical surface of the hypotube.

[0012] In some examples, the first electrode defines an inner radius of about 0.008 inches and an outer radius of about 0.0210 inches. In some examples, the hypotube defines a longitudinal length of about 0.080 inches to about 0.090 inches and a circumference of about 0.10 inches to about 0.12 inches. In some examples, the hypotube defines an inner radius of about 0.029 inches and an outer radius of about 0.034 inches. In some examples, the first electrode is rectangular prism-shaped, and the first electrode extends radially inward at least partially through the outer surface of the elongated body.

[0013] In some examples, the first electrode extends radially inward through the elongated body, at least partially into the inner lumen of the elongated body. In some examples, the one or more pressure wave emitters include five electron emitters spaced longitudinally along the central longitudinal axis of the elongated body.

[0014] In some examples, an intravascular lithotripsy (IVL) system includes an energy generator and a catheter, as referenced above.

[0015] In some examples, the energy generator is configured to control a treatment cycle by causing the electron emitter to transmit a plurality of pressure wave pulses, the plurality of pressure wave pulses including between about 80 pulses and about 300 pulses.

[0016] In some examples, a method of forming an electronic pressure wave emitter for an intravascular lithotripsy (IVL) catheter includes laser cutting a hypotube to define at least a first electrode and a second electrode positioned to define a spark gap therebetween, inserting an elongated body through the laser-cut hypotube, flowing a potting material around the laser-cut hypotube, and removing the old support structure from the hypotube.

[0017] In some examples, the spark gap includes a first spark gap, and laser cutting the hypotube further includes laser cutting the hypotube to define a third electrode positioned to define a second spark gap between the second electrode and the third electrode.

[0018] In some examples, laser cutting the hypotube includes laser cutting the hypotube so that both the first electrode and the third electrode define a rounded triangular shape and the second electrode defines a parallelogram shape. In some examples, laser cutting the hypotube includes laser cutting the hypotube so that the first electrode, the second electrode, and the third electrode all define a parallelogram shape.

[0019] In some examples, laser cutting the hypotube includes laser cutting the hypotube so that the first electrode, the second electrode, and the third electrode all define a rounded rectangular shape. In some examples, laser cutting the hypotube includes laser cutting the hypotube so that both the first electrode and the third electrode define an elliptical shape and the second electrode defines a semi-cylindrical shape. In some examples, the method further includes wiring the first electrode and the third electrode so that they are independently operable.

[0020] In some examples, the spark gap includes a first spark gap, and laser cutting the hypotube further includes laser cutting the hypotube to define a third electrode and a fourth electrode positioned to define a second spark gap between the third electrode and the fourth electrode. In some examples, laser cutting the hypotube further includes laser cutting the hypotube such that the first electrode and the third electrode are ring-shaped, the second electrode and the fourth electrode are disk-shaped, the first electrode positioned around the second electrode, and the third electrode positioned around the fourth electrode.

[0021] In some examples, the medical device includes an elongate body; a balloon positioned at a distal portion of the elongate body, the balloon configured to receive a fluid and thereby expand such that an outer surface of the balloon contacts an inner surface of a target treatment site within the patient's vasculature; and one or more pressure wave emitters positioned along a central longitudinal axis of the elongate body within the balloon, the one or more pressure wave emitters configured to propagate pressure waves radially outward through the fluid to fragment calcified lesions at the target treatment site, at least one of the one or more pressure wave emitters includes an electron emitter including a first electrode, a second electrode, and a third electrode positioned to define a first spark gap between the first electrode and a second electrode and a second spark gap between the second electrode and a third electrode, wherein the first electrode, the second electrode, and the third electrode are part of a common hypotube.

[0022] In some examples, the medical device includes a plurality of conductive wires configured to provide electrical energy to the emitter array, the plurality of conductive wires being arranged according to a wiring configuration.

[0023] In some examples, the plurality of conductive wires extend generally parallel to the central longitudinal axis. In some examples, the wiring configuration includes a single coil configuration, in which the plurality of conductive wires are helically wound around the elongated body, with adjacent coil turns of the plurality of conductive wires spaced longitudinally along the central longitudinal axis. In some examples, the wiring configuration includes a double coil configuration, in which the plurality of conductive wires are helically wound around the elongated body, with adjacent pairs of coil turns of the plurality of conductive wires spaced longitudinally along the central longitudinal axis. In some examples, the wiring configuration includes a quadruple coil configuration, in which the plurality of conductive wires are helically wound around the elongated body, with adjacent groups of four coil turns of the plurality of conductive wires spaced longitudinally along the central longitudinal axis.

[0024] In some examples, the plurality of conductive wires comprises a plurality of flat wires. In some examples, the plurality of conductive wires comprises a plurality of round wires having a flat portion along the emitter array.

[0025] In some examples, the elongate body includes an inner body and an outer body, the outer body including an inner layer and an outer layer, and the plurality of conductive wires are coiled around the outer surface of the inner layer. In some examples, the outer layer of the outer body is flowed over the plurality of conductive wires such that the plurality of conductive wires are embedded in the outer layer. In some examples, the outer layer includes a potting layer or heat shrink tubing. In some examples, the outer layer terminates proximally from the inner layer such that distal portions of the plurality of conductive wires are exposed inside the balloon.

[0026] In some examples, the elongate body includes an inner body and an outer body, and the plurality of conductive wires are coiled around an outer surface of the inner body such that the plurality of conductive wires form a reinforcing layer for the elongate body.

[0027] In some examples, each of the multiple emitters includes a respective voltage wire such that each of the multiple emitters is independently actuable. In some examples, the outer surface of the balloon includes a polymer coating. In some examples, the outer surface of the balloon includes a hydrophilic coating or a drug-based coating, such as an anti-thrombogenic coating or an anti-proliferative drug.

[0028] In some examples, the balloon includes two or more nested expandable substrates. In some examples, the two or more nested expandable substrates include at least an outer layer and an inner layer, the inner surface of the outer layer being bonded to the outer surface of the inner layer to form a single multi-layer extrusion. In some examples, the inner layer includes a high-pressure-retaining layer and the outer layer includes a urethane layer.

[0029] In some examples, the balloon further comprises a reinforcing structure. In some examples, the reinforcing structure comprises a plurality of longitudinal fibers aligned parallel to the longitudinal axis of the balloon and a plurality of braided fibers. In some examples, the plurality of longitudinal fibers comprises 4 to 8 longitudinal fibers.

[0030] In some examples, the balloon includes an outer layer, an inner layer nested within the outer layer, and a cage structure nested between the outer and inner layers, the cage structure including one or more longitudinal members oriented parallel to the longitudinal axis and one or more circumferential elements oriented perpendicular to the longitudinal axis.

[0031] In some examples, the medical device further includes a cage structure at least partially surrounding the outer surface of the balloon. In some examples, the cage structure is firmly bonded to the outer surface of the balloon. In some examples, the cage structure includes nitinol braid, metal wire, printed metal, radiopaque metal wire, or radiopaque printed metal. In some examples, the balloon includes a porous membrane configured to infuse a drug to the target treatment site.

[0032] In some examples, the balloon includes a plurality of longitudinal ribs configured to define fold guides when the balloon is folded radially inward. In some examples, the plurality of longitudinal ribs includes an odd number of ribs. In some examples, the medical device includes a spring configured to longitudinally stretch the balloon in the absence of an external force.

[0033] In some examples, the medical device includes a fracturing member positioned on an outer surface of the balloon. In some examples, the fracturing member includes a conductive wire extending along the longitudinal axis of the balloon and a plurality of piezoelectric elements positioned along the conductive wire, the plurality of piezoelectric elements configured to emit additional pressure waves against the calcified lesion. In some examples, the medical device includes a protective device positioned at a distal portion of the elongated body, the protective device configured to at least partially occlude the target treatment site and collect the fragmented lesion portion.

[0034] In some examples, the medical device includes a protective device positioned along the proximal elongate body of the balloon, the protective device configured to at least partially occlude the target treatment site and collect the fragmented lesion portion.

[0035] In some examples, the elongate body defines a lumen configured to receive a 0.0104 inch to 0.035 inch guidewire. In some examples, the medical device includes a handle positioned at a proximal end of the elongate body, the handle including an integrated power source for the emitter array. In some examples, the medical device includes a creasing member configured to contact and abrade calcified lesions. In some examples, the creasing member defines a serrated outer surface.

[0036] In some examples, the medical device includes a means for controlling a primary direction of pressure wave emission. In some examples, the medical device includes a waveguide positioned against an inner surface of the balloon and along only a portion of the circumference of the balloon, the waveguide configured to absorb or reflect pressure waves from a second portion of the circumference of the balloon. In some examples, the medical device includes ceramic, porcelain, diamond, polyimide, or polyether ether ketone (PEEK). In some examples, the waveguide defines a reflective or absorbing fluid pocket.

[0037] In some examples, the medical device includes a radiopaque indicator positioned along a first portion of the circumference of the balloon, the radiopaque indicator configured to indicate the direction of pressure wave emission. In some examples, the radiopaque indicator includes a radiopaque wire positioned along the outer surface of the balloon. In some examples, the radiopaque indicator includes a conductive wire of a fracturing element positioned along the outer surface of the balloon, the fracturing element further including a plurality of piezoelectric elements configured to emit additional pressure waves through the calcified lesion.

[0038] In some examples, each of the one or more shock wave emitters defines a respective orientation, and the medical device further includes a user input mechanism for modifying the respective orientation of the one or more shock wave emitters. In some examples, each of the one or more shock wave emitters defines a respective fixed orientation, and the medical device further includes a user input mechanism configured to independently activate a first subset of the one or more shock wave emitters independently from a second subset of the one or more shock wave emitters. In some examples, the balloon includes two or more elongated sub-balloons circumferentially oriented about a central longitudinal axis, each sub-balloon including a respective subset of the one or more shock wave emitters.

[0039] In some examples, the system further includes a sensor configured to generate sensor data indicative of at least one parameter. In some such examples, the energy generator is configured to vary the amount of delivered energy based on the sensor data. In some examples, to vary the amount of energy, the energy generator is configured to vary a current level, a voltage level, a pulse duration, a pulse frequency, or a light intensity. In some examples, the sensor data includes fluid pressure data, fluid velocity data, or temperature data. In some examples, the sensor includes an electrical impedance monitor, an inflation fluid flow rate monitor, an inflation fluid pressure monitor, a vessel wall surface monitor, a vessel diameter monitor, an interventional balloon diameter monitor, or a plaque fragmentation monitor. In some examples, the sensor includes a resonant frequency sensor, and the energy monitor is configured to vary the pressure wave frequency to approximate a resonant frequency of a calcified lesion. In some examples, the energy generator is configured to terminate the applied voltage based on the sensor data. [Brief explanation of the drawings]

[0040] These and other features, aspects, and advantages are described below with reference to the drawings, which are intended to illustrate, but not limit, the present invention, in which like characters indicate corresponding features consistently throughout similar embodiments. [Figure 1] 1 is a conceptual diagram of an exemplary intravascular lithotripsy (IVL) system including an energy generator and a catheter with a pressure wave emitter array within an interventional balloon. [Figure 2] FIG. 2 is a conceptual block diagram illustrating some example components of the energy generator of FIG. 1. [Figure 3] FIG. 2 is a conceptual diagram illustrating some exemplary components of the catheter of FIG. 1. [Figure 4A] 2 is a perspective view of a first exemplary emitter assembly of the catheter of FIG. 1. [Figure 4B] FIG. 4B is a cross-sectional view of the emitter assembly of FIG. 4A. [Figure 5A] 1. FIG. 3 is a perspective view of a second exemplary emitter assembly of the catheter of FIG. [Figure 5B] FIG. 5B is a cross-sectional view of the emitter assembly of FIG. 5A. [Figure 6A] 10 illustrates a third exemplary emitter assembly for the catheter of FIG. 1. [Figure 6B] FIG. 6B is a cross-sectional view of the emitter assembly of FIG. 6A. [Figure 6C] FIG. 6B is a cross-sectional view of the emitter assembly of FIG. 6A with the potting material layer removed to reveal the components embedded therein. [Figure 7A] 10 is a 2D representation of a first exemplary design for a laser cut hypotube of an emitter assembly, defining a non-orthogonal spark gap orientation. [Figure 7B] 7B is a 3D representation of the first exemplary hypotube design of FIG. 7A. [Figure 8A] 10 is a 2D representation of a second exemplary design for a laser cut hypotube of an emitter assembly, defining an orthogonal spark gap orientation. [Figure 8B]8B is a 2D representation of a laser cut hypotube array including the second exemplary hypotube design of FIG. 8A. [Figure 9] 10 is a 2D representation of a third exemplary design for a laser cut hypotube of an emitter assembly, defining a circular spark gap configuration. [Figure 10] 1 is a flowchart illustrating an exemplary technique for forming an emitter assembly for an IVL catheter. [Figure 11] 11A and 11B show an exemplary flex circuit for an emitter assembly of an IVL catheter. [Figure 12A] 11A and 11B show two exemplary wiring configurations for the flex circuit. [Figure 12B] 11A and 11B show two exemplary wiring configurations for the flex circuit. [Figure 13A] 1 illustrates two exemplary wiring configurations for conductively wiring an array of electron pressure wave emitters. [Figure 13B] 1 illustrates two exemplary wiring configurations for conductively wiring an array of electron pressure wave emitters. [Figure 14] 14A-14D are conceptual cross-sectional views illustrating four exemplary wiring configurations for the electron emitter array of the catheter of FIG. [Figure 15A] FIG. 1 is a conceptual diagram illustrating an exemplary wiring configuration for an electron emitter array having four emitter units. [Figure 15B] FIG. 1 is a conceptual diagram illustrating an exemplary wiring configuration for an electron emitter array having five emitter units. [Figure 16A] FIG. 1 is a conceptual diagram illustrating a first exemplary wiring configuration. [Figure 16B] FIG. 10 is a conceptual diagram illustrating a second exemplary wiring configuration. [Figure 17A] FIG. 1 is a conceptual diagram illustrating an exemplary IVL device having an optical-based emitter array. [Figure 17B] FIG. 17B is a cross-sectional view of the IVL device of FIG. 17A. [Figure 18]1A-1C are cross-sectional views of an exemplary IVL device having a multi-layer interventional balloon. [Figure 19] 1 shows two exemplary IVL devices having an interventional balloon with a protective structure. [Figure 20] 1 shows two exemplary IVL devices having an interventional balloon with a protective structure. [Figure 21] 1 illustrates an exemplary IVL device having a pair of creasing members. [Figure 22] 1 illustrates an exemplary IVL device with a fracturing element. [Figure 23] 1 shows an exemplary IVL device with a spring mechanism. [Figure 24] 1 illustrates an exemplary IVL device having a distal protection member. [Figure 25] 2 illustrates the IVL system of FIG. 1 with an exemplary closed-loop energy delivery feedback mechanism. [Figure 26] 2 illustrates an exemplary handle for the IVL catheter of FIG. 1. [Figure 27] FIG. 1 is a cross-sectional view of a first exemplary directionally focusing IVL device. [Figure 28A] FIG. [Figure 28B] FIG. 1B is a cross-sectional view of a second exemplary directionally focusing IVL device. [Figure 29A] FIG. [Figure 29B] FIG. 10 is a cross-sectional view of a third exemplary directionally focusing IVL device. [Figure 30] FIG. 1 is a front view of a flattened hypotube. [Figure 31] FIG. 1 is a perspective view of a laser cut oval hypotube. [Figure 32A] FIG. [Figure 32B] FIG. 1 is a side view of a laser cut oval hypotube as it may appear in use. [Figure 33A] FIG. [Figure 33B] FIG. 1 is a side view of an electron emitter as it may appear in use. [Figure 34] FIG. 1 is a side view of a pair of electron emitters as they may appear in use. [Figure 35A] FIG. 1 is a cross-sectional view of an IVL device. [Figure 35B] FIG. 1 is a cross-sectional view of another exemplary IVL device. [Figure 36] FIG. 2 is a cross-sectional view of a spark gap. [Figure 37] FIG. 1 is a cross-sectional view of an elliptical spark gap. [Figure 38A] FIG. 1 is a conceptual diagram illustrating an exemplary wiring configuration for an electron emitter array having two emitter units. [Figure 38B] FIG. 1 is a conceptual diagram illustrating an exemplary wiring configuration for an electron emitter array having four emitter units. [Figure 39] 1 is a flowchart illustrating an exemplary technique for forming an emitter assembly for an IVL catheter. [Figure 40] 1 is a flowchart illustrating an exemplary technique for forming electrodes from hypotubes. [Figure 41] 1 is a flowchart illustrating an exemplary technique for wiring electrodes in an IVL catheter. [Figure 42] 1 is a flowchart illustrating an exemplary method of using an IVL catheter. [Figure 43] 10 is a flowchart illustrating an exemplary method of using a multi-emitter IVL catheter. [Figure 44] 1 is a flowchart illustrating an exemplary method for controlling individual emitters in an IVL catheter. [Figure 45A] FIG. 1 is a perspective view of an exemplary emitter including various support posts. [Figure 45B] FIG. 1 is a perspective view of an exemplary emitter including various support posts. [Figure 45C] FIG. 1 is a perspective view of an exemplary emitter including various support posts. [Figure 45D] FIG. 1 is a perspective view of an exemplary emitter including various support posts. [Figure 46] FIG. 2 is a side view of an exemplary electron emitter. [Figure 47] FIG. 2 is a side view of another exemplary electron emitter. [Figure 48] 1 is a side view of a pair of electron emitters, according to some examples. [Figure 49] FIG. 1 is a side view of an exemplary three-electrode electron emitter. [Figure 50] FIG. 1B is a side view of another exemplary three-electrode electron emitter. [Figure 51] 10A-10C are side views of additional three-electrode electron emitters, according to some examples. [Figure 52] FIG. 1B is a side view of another exemplary three-electrode electron emitter. [Figure 53] 1 is a side view of a pair of three-electrode electron emitters, according to some examples. [Figure 54] FIG. 1B is a side view of another exemplary pair of three-electrode electron emitters. [Figure 55] FIG. 1 is a side view of an exemplary three-electrode spiral electron emitter. [Figure 56] FIG. 10 is a side view of another three-electrode spiral electron emitter, according to some examples. [Figure 57] 10A-10C are side views of additional three-electrode spiral electron emitters, according to some examples. [Figure 58] FIG. 1B is a side view of an exemplary three-electrode spiral electron emitter as it may appear while being articulated. [Figure 59] 1A-1C are side views of two-electrode spiral electron emitters, according to some examples. [Figure 60] FIG. 1B is a side view of an exemplary two-electrode spiral electron emitter as it may appear while being articulated. [Figure 61A] FIG. 1 is a side view of an electron emitter with an exemplary wiring configuration. [Figure 61B] FIG. 61B is a side view of two electrode pairs of the electron emitter of FIG. 61A with an exemplary wiring configuration.

[0041] Component Index 100-Intravascular Lithotripsy (IVL) System 102-Energy Generator 104-Catheter 106—extension catheter body 108-IVL device 110-Interventional Balloon 112-Pressure Wave Emitter Array 114A - First emitter 114B - Second emitter 114C-Third emitter 114D - Fourth Emitter 114E - 5th Emitter 116-Central Longitudinal Axis 118-Detachable Cable 202-Power Input Connector 204-Catheter Connector 208-Internal power supply 210-High Voltage DC-DC Converter 212-High voltage capacitors and transistor switches 216-Voltage and Current Measuring Unit 218-Processor 218 222-Device Identification Unit 224-Power Module 226-User Interface (UI) Control Processor 234-User Interface 302-Proximal catheter section 304-Distal catheter section 306-Catheter Hub 308-Access Port 310-Inflation port 312-Power Port 314-Strain Relief 316-Outer extension structure 318-Inner extension structure 320-inflation lumen 322-Guidewire lumen 324-Distal Port 326-External Balloon Coating 400—First electric emitter assembly 402A—First electrode 402B - Second electrode 402C - Third electrode 404A - First spark gap 404B - Second spark gap 406A - First Wire 406B - Second Wire 408-Expansion Fluid 410-Hypotube 412-Potting Materials 414-electrode edge 416-Elastomer layer 418-Coil 420-Polymer layer 500-Second Electrical Emitter Assembly 502A—First emitter electrode 502B-Hypotube Electrode 502C—Second emitter electrode 504-insulating layer 506-Polyimide inner extension structure 508A, 508B - Spark gap 600-Third Electrical Emitter Assembly 602A—First emitter electrode 602B-Hypotube Electrode 602C—Second emitter electrode 608-Spark Gap 700 - The first hypotube design 800 - Second Hypotube Design 802A - First electrode 802B - Second electrode 802C - Third electrode 804A - First Spark Gap 804B - Second spark gap 806-Support structure 810A-Circumferential length 810B-Longitudinal length 810C-electrode edge length 810D-Spark Gap Width 810E-Support structure width 812-Hypotube Array Design 814-bonded support 816-Removable Support 900 - The third hypotube design 902A - First ring electrode 902B - First disk electrode 902C - Second Ring Electrode 902D - Second disk electrode 904-Spark Gap 906-Support structure 910A-Circumferential length 910B-Longitudinal length 910C-Support structure width 1000-Assembly Technology 1002~1010-Assembly Steps 1100-Flex Circuit 1102A—First electrode 1102B - Second electrode 1102C - Third electrode 1104-Spark Gap 1108-Flexible PCB 1110A-Circumferential length 1110B - Longitudinal length of flex circuit 1110C-Rectangle longitudinal length 1110D - Prong Circumferential Width 1110E - Prong length 1110F-Prong gap circumferential length 1112-prong 1200A-First Flex Circuit Wiring Configuration 1200B-2 Flex Circuit Wiring Configuration 1202-Upper Wire 1204-Bottom Wire 1206-Upper Wire 1208-Intermediate Wire 1210-Bottom Wire 1300A-First wiring configuration 1300B - Secondary Wiring Configuration 1302-Inner extension structure 1304-Outer extension structure 1306-External Structure Inner Layer 1308-External structure outer layer 1310-External structure outer layer termination point 1312-Outer structure inner layer termination point 1400A~D-Wiring configuration 1402 - Wire Loopback Point 1404-Distal Balloon Cone 1406-Emitter 1408-Exposed Wire Conductor Point 1500A-1st wiring configuration 1500B-Second Wiring Configuration 1502A-4 Emitter Array 1502B-5 Emitter Array 1504-Electric Emitter 1506-Ground Wire 1600A-First wiring configuration 1600B - Secondary Wiring Configuration 1602-Emitter Array 1604-Emitter 1606-Conductive Wire 1700-IVL device 1702-Light Emitter 1704-Optical Fiber 1800-IVL device 1802-Balloon outer layer 1804-Balloon inner layer 1806-Balloon Interlayer 1810-Interventional Balloon 1900-Intervention Device 1902 - First protective structure 1904-Longitudinal member 1906-Circumferential member 2000-IVL device 2002-Second protection structure 2100-IVL device 2102-Creasing member 2200-IVL device 2202-Fracture Element 2204-Wire 2206-Piezoelectric Elements 2300-IVL device 2302-Spring 2304A-Spring proximal end 2304B-Spring Distal End 2400-IVL device 2402-Distal Protection Device 2404-Extension element 2406-Expandable basket member 2502-Sensor 2600-Catheter Handle 2602-Integrated Power Supply 2700-IVL device 2702-Wave director 2704-Fluid Pocket 2704-Visual Direction Indicator 2800-IVL device 2814-Emitter Assembly 2816-Emitter Unit 2900-IVL device 2902-Sub Balloon 3000-Hypotube 3002-Strut 3004-Spark Gap 3006-Parallelogram 3100-Laser Cut Oval Hypotube 3102-Strut 3200-Laser Cut Oval Hypotube 3202-Strut 3204-Extension body 3300-Electron Emitter 3302 - First electrode 3304 - Second electrode 3306-Longitudinal Spark Gap 3308-Extension body 3310-First Outer Ring 3312-Second Perimeter 3400 - First electron emitter 3402 - First electrode 3404 - Second electrode 3406 - First longitudinal spark gap 3408-Extension body 3410-First Outer Ring 3412-Second Outer Circle 3414 - Secondary Electron Emitter 3416-Third Electrode 3418-Fourth Electrode 3420 - Second longitudinal spark gap 3422-Third Outer Circle 3424-Fourth Outer Circle 3500-Electron Emitter 3502-Adhesive 3504a-copolymer 3504b-Polymer 3506a-wire 3506b-Wire 3508-Reinforcement 3510-Polyimide 3512-Guidewire Lumen 3700-Oval Spark Gap 3800A - First wiring configuration 3800B-Second Wiring Configuration 3802-Emitter Array 3804-Electrode Pair 3804A - First electrode pair 3804B - Second electrode pair 3804C - Third electrode pair 3804D - Fourth electrode pair 3806-Power Wire 3806A - First Ground Wire 3806B - Second Ground Wire 3808-Power Wire 3810A - First Ground Wire 3810B - Second Ground Wire 3810C-Power Wire 3810D - First connecting wire 3810E - Second connecting wire 3900~3910-Assembly Steps 4000~4004-Assembly Steps 4100~4110-Assembly Steps 4200~4204-Treatment Steps 4300~4308-Treatment Steps 4400~4404-Treatment Steps 4502 - First electrode 4504 - Second electrode 4506-Strut 4506a-Strut 4506b-Strut 4506c-prop 4506d-Strut 4508-recess 4510a-protrusion 4510b-protrusion 4510c-protrusion 4600-Emitter 4602 - First electrode 4604 - Second electrode 4606-First width 4608-Second Width 4610-Spark Gap 4612-Inner extension structure 4700-Emitter 4702 - First electrode 4704 - Second electrode 4706-Protrusion 4708-Inner extension structure 4802 - First electrode 4804 - Second electrode 4806-Third Electrode 4808-Fourth Electrode 4810 - First Spark Gap 4812 - Second Spark Gap 4814-Inner extension structure 4900-Emitter 4902 - First electrode 4904 - Second electrode 4906-Third Electrode 4908 - First Spark Gap 4910 - Second Spark Gap 4912-1st width 4914-Second Width 4916-Third Width 4918-Inner extension structure 5000-emitter 5002 - First electrode 5004-Second electrode 5006-Third Electrode 5008 - First spark gap 5010 - Second spark gap 5012-First width 5014-Second width 5016-Third Width 5018-Inner extension structure 5100-Emitter 5102 - First electrode 5104 - Second electrode 5106-Third Electrode 5108-Protrusion 5110-Inner extension structure 5200-Emitter 5202 - First electrode 5204 - Second electrode 5206-Third Electrode 5208 - First Spark Gap 5210 - Second spark gap 5212-Inner extension structure 5302 - First electrode 5304 - Second electrode 5306-Third Electrode 5308-Fourth Electrode 5310-5th Electrode 5312-6th Electrode 5314 - First Spark Gap 5316 - Second Spark Gap 5318-Third Spark Gap 5320-Fourth Spark Gap 5322-Inner extension structure 5402 - First electrode 5404 - Second electrode 5406-Third Electrode 5408-Fourth Electrode 5410-5th Electrode 5412-6th Electrode 5414 - First Spark Gap 5416 - Second Spark Gap 5418-Third Spark Gap 5420 - Fourth Spark Gap 5422-Inner extension structure 5500-Emitter 5502 - First electrode 5504 - Second electrode 5506-Third electrode 5508 - First spark gap 5510 - Second spark gap 5600-Emitter 5602 - First electrode 5604 - Second electrode 5606-Third Electrode 5608 - First Spark Gap 5610 - Second spark gap 5700-Emitter 5702 - First electrode 5704 - Second electrode 5706-Third Electrode 5708 - Proximal First Spark Gap 5710 - Proximal Second Spark Gap 5712 - Distal First Spark Gap 5714 - Distal Second Spark Gap 5800-Emitter 5802 - First electrode 5804 - Second electrode 5806-Third Electrode 5808 - First Spark Gap 5810 - Second spark gap 5900-Emitter 5902 - First electrode 5904 - Second electrode 5906-Spark Gap 6000-emitter 6002 - First electrode 6004 - Second electrode 6006-Spark Gap 6100a-Emitter 6100b-Emitter 6100c-Emitter 6100d-emitter 6102-Wire 6104-Multifilar Wire 6106-Inner extension structure 6108-First electrode 6110 - Second electrode 6112-Third Electrode 6114-Fourth Electrode DETAILED DESCRIPTION OF THE INVENTION

[0042] Although specific examples are disclosed below, the subject matter of the present invention extends beyond the specifically disclosed examples to other alternative examples and / or uses, as well as modifications and equivalents thereof. Accordingly, the scope of the claims appended hereto is not limited by any of the specific examples described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable order and are not necessarily limited to any particular disclosed order. Various operations may be described in sequence as multiple separate operations, in a manner that may be helpful in understanding a particular example, but the order of description should not be construed to imply that these operations are order-dependent. Additionally, the structures, systems, and / or devices described herein may be embodied as integrated components or as separate components.

[0043] For purposes of comparing the various examples, certain aspects and advantages of these examples are described. Not necessarily all such aspects or advantages are achieved by any particular example. Thus, for example, the various examples may be implemented in a manner that achieves or optimizes one advantage or group of advantages as taught herein, without necessarily achieving other aspects or advantages as may be taught or suggested herein.

[0044] During an intravascular lithotripsy (IVL) procedure, and more specifically, during an electrohydraulic lithotripsy (EHL) procedure, clinicians use high-energy pressure waves to destroy calcified plaque lesions within a patient's vasculature. Typical IVL systems have many drawbacks that limit the effectiveness of the treatment. For example, IVL catheters typically emit pressure waves that propagate around the entire inner circumference of the vessel wall at the target treatment site. When calcified lesions are limited to only a portion of the vessel wall circumference, e.g., eccentric, focal, and / or nodular lesions, pressure waves propagating in all directions may present less effective disruption or waste of applied energy. As a second example, in addition to directional limitations, typical IVL catheters are designed to deliver a fixed level of energy and / or power regardless of the specific clinical need (e.g., lesion size and / or density) at the target treatment site, presenting a similar set of challenges and / or effectiveness limitations.

[0045] As a third example, many IVL catheter designs include a distal interventional balloon to disperse pressure waves across surrounding tissue. In some cases, these interventional balloons may rupture in response to wave pressures above a threshold or when treating heavily calcified lesions. If the balloon ruptures around its entire circumference, the distal portion of the balloon may "bundle" around the distal catheter tip, causing more difficult and / or complicated removal from the patient, for example, by removing the outer sheath or other introducer to remove the balloon catheter. As a final example, certain features of typical interventional balloons may increase resistance to inserting the catheter into the introducer sheath at the beginning of the procedure and / or withdrawing the catheter through the introducer sheath at the end of the procedure. For example, bulky balloon "cones" and ineffective re-wrapping of balloon "pleats" may require the clinician to apply additional, excessive force to successfully perform the IVL procedure.

[0046] The present disclosure describes systems and techniques for generating and directing high-energy intravascular pressure waves for the fragmentation and / or disruption of calcified lesions within a patient's vasculature. For illustrative purposes, the techniques herein are described primarily with respect to electrically-based systems and their respective applications, e.g., peripheral vascular applications. However, it should be understood that the techniques described herein may be assumed to be equally applicable to similar systems based on other forms of energy, such as optical (e.g., laser)-based systems, and their respective applications, such as coronary artery treatment applications, except as expressly stated below.

[0047] Generally, the systems described herein include an energy source and an IVL catheter with a distal IVL device that includes an interventional balloon and a pressure wave emitter array. During a lesion disruption procedure, a clinician may advance the interventional balloon to a target treatment site within a patient's vasculature and inflate the balloon with an inflation fluid, such as a saline / contrast fluid mixture, until the balloon contacts at least a portion of the local vessel wall. The clinician then activates an energy generator, causing the catheter to generate cavitation bubbles within the fluid-filled balloon and propagate high-energy pressure waves through the balloon and the calcified lesion. Secondary pressure waves may also result from the subsequent collapse of the fluid cavitation, further destabilizing the internal structure of the lesion.

[0048] FIG. 1 is a conceptual diagram illustrating an exemplary IVL system 100. As shown in FIG. 1, the IVL system 100 includes at least an energy generator 102 and an IVL catheter 104 detachably coupled to the energy generator 102, such as via a catheter-connector interface 204. In some examples, a detachable cable 118 can be connected between the generator 102 and the catheter 104 to provide energy to the catheter 104. As described in further detail below, an energy source (e.g., a battery, a capacitor, etc.) may additionally or alternatively be integrated into the catheter 104. The catheter 102 includes an elongated body 106 and an IVL device 108 positioned at a distal portion of the elongated body 106. The elongated body 106 is configured to navigate a patient's tortuous vasculature toward a target treatment site, such as a calcified plaque lesion within a blood vessel.

[0049] As shown in FIG. 1 , the IVL device 108 includes a fluid-inflatable interventional balloon 110 and a pressure wave emitter array 112 positioned within the balloon 110. The emitter array 112 includes one or more individual emitter units 114A-114E. For example, the interventional balloon 110, or the distal portion of the elongate body 106 passing therethrough, may define a central longitudinal axis 116, and the emitter units 114A-114E may be distributed longitudinally along the central longitudinal axis 116. Note that the individual emitter units 114A, 114E are also referred to throughout this disclosure as "emitters" (e.g., with reference to the emitter unit as a whole) as well as "emitter assemblies" (e.g., with reference to a particular arrangement of subcomponents that collectively form the emitter unit).

[0050] 1 includes a first emitter unit 114A, a second emitter unit 114B, a third emitter unit 114C, a fourth emitter unit 114D, and a fifth emitter unit 114E. While five emitter units 114 are shown in FIG. 1 , the emitter array 112 of the IVL device 108 may include as few as one individual emitter unit to as many emitter units as can reasonably fit within the balloon 110. Each emitter unit 114 is configured to receive energy from the energy generator 102 and use the received energy to generate and transmit high-energy pressure waves through the balloon 110 and across the target treatment site. As described in further detail below, the energy generator 102 may generate and transmit energy in the form of electrical energy, light energy, or a combination thereof. For example, the emitter unit 114 may use the received energy to generate cavitation within the fluid inside the balloon 110, propagating one or more high-energy pressure waves radially outward through the balloon 110 and the calcified lesion. In some, but not all, cases, a secondary set of high-energy pressure waves may subsequently result from the collapse of the fluid cavitation, further destabilizing the internal structure of the calcified plaque lesion. In some examples, one or more of the emitters 114 may include an electrically-based emitter configured to receive electrical energy from the generator 102, such as via one or more conductive wires, and generate a spark between a pair of electrodes, thereby triggering initial cavitation. Additionally or alternatively, one or more of the emitters 114 may include an optically-based emitter configured to receive a high-energy optical (e.g., light) signal from the generator 102, such as via one or more fiber optic wires or tubes, and direct the light signal to trigger initial cavitation.

[0051] Figure 2 is a block diagram illustrating some example components of the energy generator 102 of Figure 1. A power input 202 (e.g., for conductively coupling to a wall port or another power source) connects to a power module 224 and an internal power source 208. As shown in Figure 2, the power module 224 can include, by way of various non-limiting examples, a high-voltage DC-DC converter 210, a high-voltage capacitor and transistor switch 212, a voltage and / or current measurement unit 216, and a device identification unit 222 configured to determine whether the catheter 104 is an approved device while the catheter 104 is connected via the catheter connector 204. For example, the energy generator 102 may be configured to disable energy output to the catheter connector 204 when an unidentified device is connected.

[0052] The generator 102 may include memory and one or more processors, such as the processor 218 and / or a user interface control processor 226. The UI control processor 226 is configured to provide functionality for a user interface 234 of the energy generator 102, such as a display screen, a touch screen, buttons, or other manual controls that allow a user (e.g., a clinician) to operate the energy generator 102.

[0053] 2, in addition to or as an alternative to the electrical energy-based components, in some examples, the energy generator 102 includes an optical signal unit configured to convert electrical power (e.g., from the power input 202) into an optical beam, such as a laser beam. The optical signal unit can then direct the optical signal into a carrier cable, such as an optical fiber, coupled to or integrated as part of the catheter 104 (FIG. 1).

[0054] FIG. 3 is a conceptual diagram illustrating some exemplary components of the catheter 104 of FIG. 1. As shown in FIG. 3, the catheter 104 includes a proximal portion 302 and a distal portion 304 opposite the proximal portion. The proximal portion 302 may include a catheter hub 306 and / or a handle (as described in further detail below). The catheter hub 306 defines an access port 308, an inflation port 310, and a power port 312. The access port 308 allows a clinician to manipulate (e.g., steer, actuate, etc.) the distal portion 304, including the IVL device 108. The clinician may use the inflation port 310 to inject an inflation fluid, such as a saline / contrast fluid solution, to expand the interventional balloon 110 to an inflated or expanded state, with the outer surface of the balloon 110 contacting the inner surface of the blood vessel wall at the target treatment site. The power port 312 is configured to interconnect with a power cable (not shown) and conductively couple the catheter 104 to the energy generator 102 (FIGS. 1 and 2). The catheter hub 306 may also include a strain relief portion 314 to reinforce the elongated body 106 and reduce kinking.

[0055] 3 , in some, but not all, examples, the elongated body 106 can include an outer extension structure 316 and an inner extension structure 318. For example, the outer extension structure 316 can include a sheath or outer catheter defining an inflation lumen 320. In some examples, the outer extension structure 316 forms a proximal extension of the interventional balloon 110, and thus, the inflation lumen 320 fluidly couples the inflation port 310 to the interior cavity of the interventional balloon 110.

[0056] The inner elongated structure 318 may include an inner catheter or other inner structure positioned within the inflation lumen 320 and configured to hold the emitters 114 of the emitter array 112. In some such examples, the inner elongated structure 318 itself may define an inner lumen 322 configured to receive a guidewire, for example, via a distal port 324. In other examples, as shown in subsequent figures, the elongated body 106 includes only a single layer defining a single inner lumen.

[0057] As described above, the catheter 104 is configured to advance through the patient's vasculature (e.g., through an arteriotomy) to position the balloon 110 adjacent to a calcium lesion located at a target treatment site. The IVL device 108 may be configured to generate a first pressure wave (or waves) by expanding the volume of liquid resulting from a phase change from liquid to liquid-vapor, which may rapidly expand gas bubbles. A second pressure wave may occur when the gas bubbles subsequently collapse. In some examples, the balloon 110 has an outer coating 326 made, for example, from a polymer and / or other material, as described in further detail below. For example, the outer coating 326 may include a hydrophilic coating to improve its ability to traverse the patient's vasculature. Additionally or alternatively, the outer coating 326 may include a drug coating, such as an antithrombotic or antiproliferative drug, as well as excipients to aid in drug delivery. As described in further detail below, the balloon 110 may be porous / semi-permeable (e.g., a "percolated" balloon) or porous / semi-permeable for infusion of drugs into the blood vessel, as compared to infusion into the blood vessel through the lumen.

[0058] FIG. 4A is a perspective view of a first exemplary emitter assembly 400 (e.g., emitter assembly 114A of FIG. 1) of the catheter 104 of FIG. 1, and FIG. 4B is a cross-sectional view of the emitter 400 of FIG. 4A. In particular, FIGS. 4A and 4B show an electron emitter 400 including a pair of conductive electrodes 402A, 402B defining a first spark gap 404A therebetween. In this example, the electrodes 402A, 402B are configured to receive electrical energy (e.g., current) from the energy generator 102 (FIGS. 1 and 2) via conductive wires 406A, 406B. The resulting spark across the spark gap 404 is configured to cavitate a surrounding expanding fluid 408 and propagate a high-energy pressure wave through the expanding fluid 408.

[0059] In accordance with the techniques of the present disclosure, one or both electrodes 402A, 402B are subsections or portions of the cylindrical surface of a common hypotube 410. As used herein, "hypotube" refers to a metal tube having micromachined features along its length.

[0060] That is, a specific section of the cylindrical hypotube 410 may be removed (e.g., laser cut) to form one or both electrodes 402A, 402B and the spark gap 404A therebetween. In some such examples, a potting material 412, such as an adhesive layer, may be poured over the remaining portions of the cylindrical hypotube (e.g., electrodes 402A, 402B) and then cured or allowed to harden to hold the hypotube portions in place. Some examples of potting material 412 include polyurethane-based, acrylic-based, silicone-based, or any other suitable material with sufficient dielectric strength. In some, but not all, examples, excess potting material 412 may later be removed (e.g., scored, ablated, or milled) from between the electrodes 402A, 402B to re-establish the spark gap 404A, if necessary.

[0061] 4B, the hypotube 410 of the emitter assembly 400 includes two pairs of conductive electrodes and respective spark gaps therebetween: a first pair of electrodes 402A, 402B (having a spark gap 404A therebetween) and a second pair of electrodes 402B, 402C (having a spark gap 404B therebetween). That is, electrode 402B may be used as a common electrode for both electrodes 402A, 402C, aligned with opposing edges of electrode 402B. Specifically, a first edge 414A of the first electrode 402A is aligned with a second edge 414B of the second electrode 402B to define the first spark gap 404A. Additionally, a third edge 414C of the second electrode 402B is aligned with a fourth edge 414D of the third electrode 402C to define a second spark gap 404B. In some instances, the two pairs of conductive electrodes may be wired to be simultaneously operable, or in other instances, they may be wired to be separately operable, as described in further detail below. Such a wiring configuration allows a clinician to select which emitter assembly, or even a particular electrode pair, to activate for treatment of a calcified plaque lesion. It should be noted that while a two-electrode pair system is primarily shown and described herein, more electrode pairs may also be incorporated into the emitter assembly 400.

[0062] In some examples, the hypotube 410 may similarly define a three-electrode system, but rather than defining two emitter electrode pairs, the three electrodes may consist of a working electrode, a counter electrode, and a reference electrode. For example, the working and counter electrodes are configured to generate pressure waves, while the role of the reference electrode is to act as a reference in measuring and controlling the working electrode potential without passing any current itself.

[0063] As further shown in FIG. 4B , the electron emitter assembly 400 includes multiple nested layers (e.g., to define the elongated body 106 therein). For example, within the hypotube 410 and potting material 412, the emitter assembly 400 includes an elastomeric layer 416, such as a thermoplastic elastomer. One such example is a polyether block amide (e.g., PEBAX® manufactured by Arkema SA, Colombes, France). In some, but not all, examples, within the elastomeric layer 416, the emitter assembly 400 may include a coil 418, such as a coiled turn of the conductive wire 408 or a coil of a spring associated with the interventional balloon 110 ( FIG. 1 ), as described in further detail below with respect to FIG. 23 . Finally, the innermost layer of the emitter assembly 400 is a second polymer layer 420, such as a polyimide. The polymer layer 420 may be tubular and define a portion of the guidewire lumen 322 therein.

[0064] According to some examples, the emitter assembly 400 is configured to implement a relatively high redundant voltage. Therefore, materials of construction should be selected for low degradation so that the IVL device 108 will last for the duration of an IVL treatment. In some examples, the catheter 104 is configured for single use only, while the energy generator 102 is considered theoretically infinitely reusable. In some examples, the number of pressure wave "cycles" of an IVL treatment may range from about 80 wave pulses to about 300 wave pulses, although a treatment may include more or fewer wave pulses depending on the unique clinical parameters presented.

[0065] In some examples, the electrode pairs 402A / 402B and 402B / 402C may be fabricated from narrow copper strips that are secured on the inner elongated structure 318 inside the interventional balloon 110 (FIGS. 1, 3). In some, but not all, examples, each electrode 402 may be cut, bent, or otherwise formed to define an angle with respect to the central longitudinal axis 116. That is, the electrodes 402 may be configured to "lean" away from the central longitudinal axis 116 in the absence of an external force. During delivery through the patient's vasculature, the radially inward compressive force from the deflated balloon 110 may cause the electrodes to "flatten" toward the central longitudinal axis 116.

[0066] Figure 5A is a perspective view of a second exemplary electron emitter assembly 500 of the catheter 104 of Figure 1, and Figure 5B is a cross-sectional view of the emitter assembly 500 of Figure 5A. Specifically, the exemplary emitter assembly 500 of Figures 5A and 5B includes two laser-cut "emitter" electrodes 502A, 502C welded to a laser-cut polyimide "coupler" layer 504. In this example, the emitter electrodes 502A, 502C are shown as generally elliptical, although other geometric shapes are contemplated.

[0067] A laser-cut "hypotube" electrode 502B is also attached to the coupler layer 504 between the emitter electrodes 502A, 502C to define respective spark gaps 508A, 508B. In this example, the hypotube electrode 502B is shown as being generally semi-cylindrical in shape, although other geometric shapes are contemplated. A series of flat wires 406A, 406D may be utilized to deliver energy from the energy generator 102 (FIGS. 1 and 2) to the emitter electrodes 502A, 502C, from the emitter electrodes 502A, 502C to an additional emitter unit 114 (FIG. 1) within the IVL device 108, and from the additional emitter unit 114 back to ground.

[0068] As shown in FIGS. 5A and 5B, in this example, a polyimide inner extension structure 506 extends distally through the core of the emitter assembly 500, as seen on the outside of the assembly in FIG. 5A or the innermost circle in FIG. 5B. The portion of the outermost concentric ring above the central longitudinal axis 116 is a laser-cut hypotube electrode 502B, which passes energy to the opposite mirrored "emitter" electrodes 502A, 502C. The portion of the outermost concentric ring below the central longitudinal axis 116 is another emitter electrode 502C welded to wire 406D. Continuing away from the emitter assembly on both sides are additional flat wires 406 that connect to and leave the emitter to carry the energy to generate the pressure wave and then return the voltage to ground. The outer portion of the emitter assembly 500 as seen in FIG. 5A, or the central core as seen in FIG. 5B, is the first spark gap 508A where current from the emitter electrode 502A "jumps" to the hypotube electrode 502B.

[0069] In some, but not all, examples, a reflective surface or coating may be applied to surfaces within the spark gap 508 to reflect the emitted pressure waves radially outward toward the interventional balloon 110 (FIG. 1). The reflective surface or coating may be an acoustically opaque and non-conductive (e.g., insulating) material such as, for example, ceramic, porcelain, diamond, polyimide, polyetheretherketone (PEEK), another similar material, or any suitable combination thereof.

[0070] The penultimate core, which can be seen in FIG. 5A located directly below both the laser cut hypotube 502B and the emitter electrode 502A, and wrapped around the central core in FIG. 5B, is a coupler or insulating material 504 that creates a space between the inner lumen and the emitter electrode 502A.

[0071] FIG. 6A illustrates a third exemplary electron emitter assembly 600 for the catheter 104 of FIG. 1 , FIG. 6B is a cross-sectional view of the emitter assembly 600, and FIG. 6C is a cross-sectional view of the emitter assembly 600 with the potting material 412 removed to reveal the components embedded therein. Specifically, the emitter assembly 600 includes two laser-ablated “emitter” electrodes 602A, 602C positioned on opposite sides of a hypotube electrode 602B. As shown in FIG. 6C , in some but not all examples, the emitter electrodes 602A, 602C are configured to breach the outer surface of the inner elongated structure 506, for example, to help hold the emitter electrodes 602A, 602B in place. In some such examples, the emitter electrodes 602A, 602B extend radially inward through the entire wall of the inner elongated structure 506 and partially into the guidewire lumen 322. The emitter electrodes 602A, 602B may also be potted in place, for example embedded within the potting material 412.

[0072] The third exemplary emitter assembly 600 shown in Figures 6A, 6B, and 6C shares similarities with the second exemplary emitter assembly 500 shown in Figures 5A and 5B, except for the differences described herein. For example, in both examples, a polyimide inner extension structure 506 extends distally through the core of the emitter assembly, as seen on the outside of the assembly 600 in Figure 6A, or in the radially innermost circles in Figures 6B and 6C.

[0073] The outermost concentric ring portion above the central longitudinal axis 116 is a laser-cut hypotube electrode 602B that passes energy to the opposing emitter electrodes 602A, 602C. As mentioned above, below the central longitudinal axis 116 in FIG. 6C are two emitter electrodes 602A, 602C that extend radially inward through both the outer and inner surfaces of the elongated structure 506. As particularly shown in FIG. 6C , multiple flat wires 406 are distributed circumferentially around the longitudinal axis 116, directed toward and away from the emitter electrodes 602A, 602C to carry energy for generating high-energy pressure waves, and then directed back proximally to ground. In FIG. 6B , these flat wires 406 are represented as dashed lines embedded within the potting material 412; in FIG. 6C , they are represented as solid components because the potting material 412 has been removed to facilitate visualization of the flat wires 406 within this space.

[0074] 6A and 6B, the spark gap 608A (e.g., where current from the emitter electrode 602A “jumps” to the hypotube electrode 602B) is shown as being substantially filled with potting material 412. In other examples, a section of the potting material 412 in the spark gap 608A may be milled or otherwise removed. The potting material 412 shown beneath both the laser-cut hypotube 602B and the emitter 602A in FIG. 6A and wrapped around the inner extension structure 506 may comprise any suitable adhesive or potting material, such as a UV adhesive, epoxy, or reflow polymer.

[0075] In some examples, pressure reflective material may be added within and / or around the spark gap 608A, the reflective material configured to redirect radially inward pressure waves so that they travel radially outward toward the intervention balloon 110 (FIGS. 1, 3).

[0076] 7A-9 show three exemplary electrode design configurations for laser-cut hypotubes 410 (FIG. 4B) that define two or more conductive electrodes for electron emitter assembly 400 (FIG. 4). These hypotube designs can be cut (e.g., laser cut) from a common 2D surface. In some examples, the electrode designs may be cut from a flat 2D surface and then formed into a cylindrical hypotube. In other examples, the electrode designs may be cut directly from the cylindrical hypotube.

[0077] Exemplary materials that can be used to cut conductive electrodes from a common flat surface or cylindrical hypotube include 304 SST, titanium, cobalt chrome, 316 SST, or nickel-titanium alloys (e.g., Nitinol), although other options are suitable as long as they have low degradation, low resistivity, ductility, and are machinable through the use of a laser. Additionally, electrodes may be cut directly from the stent, so a flat sheet of material is not strictly necessary. In some examples, all of the emitters 114 in the emitter array 112 (FIG. 1) may be cut from a single continuous hypotube. This has the advantage of eliminating the need to weld individual emitters 114 to wire, thus facilitating the manufacturing process.

[0078] FIG. 7A is a 2D representation of a first exemplary design for a laser-cut hypotube 700 of the electron emitter assembly 400 (FIG. 4), and FIG. 7B is a 3D representation of the first exemplary hypotube 400 of FIG. 7A. For example, FIG. 7B shows what the hypotube 400 of FIG. 7A looks like when rolled into its final tubular form. As one non-limiting illustrative example, in the tubular form shown in FIG. 7B, the cylindrical hypotube 700 can define an inner radius of about 0.025 to about 0.035 inches (e.g., about 0.03 inches) and an outer radius of about 0.03 inches to about 0.04 inches (e.g., about 0.035 inches).

[0079] The hypotube design 700 shown in Figures 7A and 7B largely corresponds to the hypotube design 410 shown in Figure 4. For example, the hypotube 700 defines a first electrode pair 402A / 402B having a spark gap 404A therebetween and a second electrode pair 402B / 402C having a spark gap 404B therebetween. Figures 7A and 7B illustrate a generally non-orthogonal hypotube design in which the electrodes 402 are irregularly shaped such that the spark gaps 404A, 404B are not oriented parallel to the central longitudinal axis 116. In particular, as shown in Figure 7A, the electrodes 402A and 402C are generally shaped as rounded triangles (e.g., three-sided shapes with rounded corners), and the electrode 402B is generally shaped as a parallelogram. However, other configurations are contemplated, such as all three electrodes 402A, 402C being shaped as parallelograms.

[0080] The relative angle between the spark gaps 404A, 404B and the central longitudinal axis 116 may be varied across different emitters 114 (FIG. 1) to provide different propagation directions of the emitted pressure waves. In some such instances, a clinician can independently activate different emitters to control this aspect of the IVL treatment.

[0081] 8A is a 2D representation of a second exemplary design 800 for a laser-cut hypotube of electron emitter assembly 400 (FIG. 4). Compared to hypotube 410 shown in FIGS. 7A and 7B, hypotube design 800 includes a more orthogonal design in which spark gaps 804A, 804B are oriented parallel to central longitudinal axis 116. For example, electrodes 802A, 802C are more regular in shape, such as substantially rectangular, such that spark gaps 804A, 804B are substantially parallel to longitudinal axis 116.

[0082] For purposes of illustration, some non-limiting examples of various dimensions of hypotube 800 are shown in Figure 8. For example, hypotube 800 (while in the flat configuration shown in Figure 8) may define a rectangle having a circumferential length 810A of about 0.1 inches. Rectangular width 810B (e.g., the longitudinal length of hypotube 800 along longitudinal axis 116) can range from about 0.080 inches to about 0.090 inches.

[0083] Each of the electrodes 802A, 802B, 802C may include an emitting edge 414 (FIG. 4) defining a spark gap 804A, 804B therebetween, e.g., having a length 810C of about 0.040 inches to about 0.055 inches. The resulting spark gap may then define a gap width of about 0.0025 inches to about 0.0040 inches. The hypotube 800A may further include a plurality of support structures 806 configured to at least temporarily hold the primary structure (e.g., the electrode 802) in place during fabrication of the emitter assembly 114. These support structures 806 may then be removed, e.g., after the electrode 802 is suspended in place via the potting material 412 (FIG. 4). The support structures 806 may define a width 810E of about 0.0020 inches.

[0084] FIG. 8B is a 2D representation of a hypotube array design 812 including multiple instances 800A, 800D of the second hypotube design 800 of FIG. 8A. As referenced above, in some examples, two or more emitter units 114 of the emitter array 112 (FIG. 1) may be cut from a single continuous hypotube or, alternatively, cut from a common plane and then formed into a cylindrical hypotube. This technique eliminates the need to weld individual emitters 114 to wires, thus facilitating the manufacturing process. That is, instead of conductively coupled wires 406 (FIG. 4), individual hypotubes 800A-800D may be conductively coupled via conductively coupled supports 814 cut from the same substrate as the emitters. The exemplary design 812 shown in FIG. 8B includes multiple removable supports 816. Removable supports 816 may be first cut into the common substrate with hypotubes 800A, 800D and bonding supports 814 to help hold these components in place during fabrication, and then subsequently removed after hypotube array 812 has been assembled into a functioning emitter unit.

[0085] 9 is a 2D representation of a third exemplary design 900 for the laser-cut hypotube 410 of the electron emitter assembly 400 (FIG. 4). Similar to hypotube design 800 (FIG. 8), hypotube design 900 (while in the planar configuration shown in FIG. 9) can define a rectangle having a circumferential length 910A of approximately 0.1 inches. The rectangle width 910B (e.g., the longitudinal length of the hypotube 900 along the longitudinal axis 116) can range from approximately 0.080 inches to approximately 0.090 inches.

[0086] In comparison to hypotube designs 700 ( FIGS. 7A and 7B ) and 800 ( FIGS. 8A and 8B ), both of which define a generally linear spark gap configuration, the electrodes 902A, 902D of hypotube design 900 are shaped and oriented to define a substantially round or circular spark gap 904A, 904D. For example, hypotube design 900 may include two substantially ring-shaped electrodes 902A, 902C, each defining an outer radius of approximately 0.0210 inches and an inner radius of approximately 0.013 inches. At the center of ring electrodes 902A, 902C are disk electrodes 902B, 902D, respectively. Disk electrodes 902B, 902D may define an outer radius of approximately 0.0090 inches. Thus, electrode pairs 902A / 902B and 902C / 902D may define respective ring- or semi-ring-shaped spark gaps 904 therebetween having a gap width of approximately 0.0040 inches. Similar to hypotube 800 (FIG. 8), hypotube 900 may initially include one or more vertical support structures 906 that may be removed once electrodes 902 are adhered in place. Support structures 906 may define a width 910C of, for example, approximately 0.0030 inches.

[0087] Figure 10 is a flowchart 1000 illustrating an exemplary technique for forming an electron emitter assembly for an IVL catheter, such as the emitter assembly 400 shown in Figure 4A. The technique of Figure 10 includes cutting a hypotube and defining one or more pairs of conductive electrodes (1002) aligned to define a respective spark gap therebetween according to an electrode design, such as one of designs 700-900 of Figures 7A-9, respectively. The technique further includes inserting (1004) an extension structure, such as inner extension structure 318 of Figure 4A, into the lumen of the cut hypotube.

[0088] In some, but not all, examples, additional layers may be inserted between the hypotube 410 and the inner extension structure 318 to help provide structural support, improve thermal conductivity, or increase energy efficiency, as illustrated in FIG. 4B. For example, a pressure reflective material, a thermoplastic elastomer 416, a wire coil 418, or a polyimide layer 420 may be inserted (1006) if not already present. The technique of FIG. 10 further includes flowing a potting material 412 around the assembled components and allowing or solidifying the potting material layer 412 to hold the assembled components in place relative to one another (1108).

[0089] In some, but not all, examples, the technique of FIG. 10 includes removing 1010 a portion of the potting material 412 from between the conductive electrodes of the hypotube to re-establish the spark gap. For example, step 1010 may include milling the potting material between the electrodes or removing the potting material via laser ablation, variable speed rotary tool removal, or other mechanical removal. In other examples, prior to flowing 1008 the potting layer, the technique of FIG. 10 may further include filling the spark gap with an easily removable material to block the potting material, and then removing the material. In other examples, the hypotube may be overmolded onto an existing potting layer such that the spark gap is not filled in the first place.

[0090] 10 further includes removing old structural components from the hypotube 410. For example, as shown in FIG. 8A, the temporary support structure 806 can be removed from between the electrodes 802 once the electrodes 802 are secured in place.

[0091] 11A and 11B show an exemplary flex circuit 1100 for the electron emitter assembly 400 (FIG. 4) of the IVL catheter 104 (FIG. 1). For example, conductive electrodes (e.g., copper strips) 1102A, 1102C can be printed on a flexible planar substrate 1106 to define respective spark gaps 1104 therebetween. The flexible substrate 1106 can then be rolled into the tubular shape shown in FIG. 11B and then wired to the remainder of the emitter assembly 400 (FIG. 4). Such a technique can significantly reduce the manufacturing time of an IVL catheter 104 including such a circuit 1100.

[0092] For illustrative purposes, FIG. 11A includes some non-limiting example dimensions of the flex circuit 1100. For example, the flex circuit 1100 may include a circumferential length 1110A of approximately 0.082 inches and an axial length 1110B (e.g., parallel to the longitudinal axis 116) of approximately 0.080 inches. The planar substrate may further define a primary rectangular body 1108 and two axial prongs 1112A, 1112B. The primary rectangular body 1108 may have dimensions of a circumferential length 1110A of approximately 0.082 inches by an axial length 1110C of approximately 0.060 inches. The axial prongs 1112 may likewise be substantially rectangular, defining a circumferential width 1110D of approximately 0.012 inches and an axial length 1110E of approximately 0.020 inches. The axial prongs 1112A, 1112B may be circumferentially separated by a gap 1110F of approximately 0.046 inches.

[0093] 12A and 12B show two exemplary wiring configurations 1200A and 1200B, respectively, for the emitter array 112 (FIG. 1) of an IVL device 108 that includes two flex circuits 1100A and 1100B (e.g., the flex circuit 1100 of FIGS. 11A and 11B). Specifically, FIG. 12A shows exemplary wiring configuration 1200A in which flex circuits 1102A and 1102B are wired in parallel. The upper conductive wire 1202 (solid line) connects to a voltage input, and the lower conductive wire 1204 (dashed line) connects to a ground voltage.

[0094] 12B shows another exemplary wiring configuration 1200B in which the flex circuits 1102A, 1102B are wired to be independently operable. For example, a top conductive wire 1206 provides a connection between a voltage input and the flex circuit 1102B, and a middle conductive wire 1208 (solid line) provides a connection between a voltage input and the flex circuit 1102A. A bottom conductive wire 1210 provides a common connection to a ground voltage for both flex circuits 1102.

[0095] 13A and 13B show two exemplary wiring configurations 1300A, 1300B, respectively, for conductively wiring the electron emitter array 400 ( FIG. 4 ). In the example 1300A shown in FIG. 13A , the elongated body includes an inner elongated structure 1302 (e.g., the polyimide inner layer 420 of FIG. 4 ) and an outer elongated structure 1304 having two nested layers: an inner layer 1306 and an outer layer 1308. A plurality of conductive wires 406, such as “flat” or “rectangular” wires, are axially coiled along the outer surface of the inner layer 1306 of the outer elongated structure 1304. The outer layer 1308 of the outer elongated structure 1304, such as heat shrink tubing, thermoplastic tubing, or potting material 412 ( FIG. 4 ), may then be reflowed over the conductive wires 406 such that the conductive wires 406 are embedded in the outer layer 1308 of the outer elongated structure 1304.

[0096] In some examples, the outer layer 1308 of the outer elongated structure 1304 may terminate a predetermined distance 1310 proximally from the distal end 1312 of the inner layer 1306 such that a distal portion of the conductive wire 406 is exposed and may be adjusted beneath the interventional balloon 110 ( FIG. 1 ). The conductive wire 406 may comprise a flat wire, a round wire, or a combination thereof. For example, in some examples, the conductive wire 406 comprises a round wire having a “flattened” portion near the emitter 114.

[0097] In wiring configuration 1300A, the adhesive outer layer 1308 is "tacked" to the inner layer 1306 to reinforce the structure of the interventional balloon 110 (FIG. 1). This can help prevent the balloon 110 from "bellowing" during insertion or removal of the IVL device 108. The wire can also function as a reinforcing member for the outer extension structure 1304.

[0098] For comparison, Figure 13B shows a different configuration 1300B in which the conductive wire 406 is coiled directly around the inner elongated structure 1302. In some examples, the use of a flat wire (e.g., a round wire with a flat portion near the emitter) helps reduce the overall radial profile of the IVL device 108. In this configuration 1300B, the conductive wire 406 can also serve as a reinforcing member for the inner elongated structure 1302 (e.g., the coil layer 418 in Figure 4B).

[0099] 14A-14D are conceptual cross-sectional views illustrating four exemplary wiring configurations 1400A-1400D, respectively, of the electron emitter array 112 of the catheter 104 of FIG. 1. In each of these four examples, the conductive wire 406 extends distally along the outer surface of the inner elongated structure 318 but is not rigidly coupled to the inner elongated structure 318.

[0100] 14A, the conductive wires 406 extend generally linearly along the distal direction, e.g., along the central longitudinal axis 116. In this configuration, the emitters 1406 may be wired in series, or in other examples, may be a combination of parallel and series wiring.

[0101] In comparison, in the second exemplary wiring configuration 1400B of FIG. 14B , the conductive wire 406 is coiled helically around the inner extension structure 318 according to a “single wrap” configuration. In the single wrap wiring configuration 1400B, two or more wires 406A, 406B are intercoiled with respective longitudinal spaces between adjacent coil turns. In these “coiled” configurations shown in FIGS. 14B, 14C, and 14D, the wire coil helps to provide structural support for the inner extension structure 318, for example, by forming the coil layer 418 of FIG. 4B . In some such examples, the emitter array may be wired according to an “n+1” configuration, where the number of conductive wires 406 is one greater than the number of emitters 1406, such that each emitter has its own voltage supply wire but all share a common ground wire.

[0102] In a third exemplary wiring configuration 1400C of FIG. 14C, the conductive wire 406 is helically wrapped around the inner elongated structure 318 according to a "double wrap" configuration. In the double wrap wiring configuration 1400C, the wire 406 is intercoiled as wire pairs with longitudinal spaces between adjacent pairs of coil turns. The wire jacket portion 1408 may be removed (e.g., ablated) as needed to conductively couple the wire 406 to the electrode hypotube 410 (FIG. 4).

[0103] In a fourth exemplary wiring configuration 1400D of FIG. 14D , the conductive wires 406 are helically coiled around the inner elongated structure 318 according to a “quadruple wrap” configuration. In the quadruple wrap wiring configuration 1400D, the wires 406 are intercoiled in groups of four wires with longitudinal spaces between adjacent groups of four coil turns. The wire jacket portions 1408 may be removed (e.g., ablated) as needed to conductively couple the wires 406 to the electrode hypotube 410 ( FIG. 4 ). In other examples, the wires may be grouped and coiled in numbers greater than four.

[0104] FIG. 15A is a conceptual diagram illustrating an exemplary wiring configuration 1500A for an electron emitter array 1502A having four emitter units 1504A-1504D, and FIG. 15B is a conceptual diagram illustrating an exemplary wiring configuration 1500B for an electron emitter array 1502B having five emitters 1504A-1504E. While only four-emitter and five-emitter assemblies 1502 are shown, it should be understood that any suitable and practical number of emitter units 1504 can be implemented within the IVL device 108. As mentioned above, both wiring configurations 1500A, 1500B are examples of an "n+1" configuration, in which the number of conductive wires is one greater than the number of emitters 1504; each emitter 1504 has its own voltage supply wire, but all emitters 1504 share a common ground wire 1506. In such a configuration, individual emitters 1504 are independently operable, providing enhanced control over IVL therapy for the clinician.

[0105] FIG. 16A is a conceptual diagram illustrating a first exemplary wiring configuration 1600A of an electron emitter array 1602 having four emitter units 1604A-1604D. Similar to FIGS. 15A and 15B, FIG. 16A illustrates the emitter units 1604 wired according to an “n+1” configuration and a configuration in which the emitter assemblies 1604 are wired in parallel. Some exemplary advantages of the parallel wiring configuration 1600A include the ability to carry higher currents across the emitter units 1604. The parallel wiring configuration 1600A also allows each individual emitter unit 1604 to be activated (or “fired”) independently of the other emitter units. Additionally, the parallel wiring configuration 1600A can reduce the overall resistance of the IVL system 100 (FIG. 1). For example, by individually powering a single emitter unit 1604, a larger current can be generated across the spark gap 404 (FIG. 4), thereby reducing the required number of resistors in the corresponding electrical circuit.

[0106] Configuration 1600A can also allow for a reduction in overall system voltage, leading to, for example, reduced energy consumption. The ability to individually power each emitter 1604 and select the sequence of firing order for each emitter unit 1604 allows for greater overall control of the IVL device 108, including how and where the applied energy is directed, as described in further detail below.

[0107] FIG. 16B is a conceptual diagram illustrating a second exemplary wiring configuration 1600B of the electron emitter array 1602 of FIG. 16A. In wiring configuration 1600B, a combination of both parallel and series wiring techniques may be implemented, enabling the benefits of both configurations. For example, emitters 1604A and 1604B are connected in series, while the other emitters 1604 are connected in parallel. In particular, wiring configuration 1600B allows a clinician to simultaneously activate (1) emitters 1604A and 1604D (e.g., using wires 1606A and 1606C), (2) emitters 1604C and 1604D (e.g., using wires 1606B and 1606C), or (3) emitters 1604A and 1604B (e.g., using wires 1606A and 1606B). However, FIG. 16B is not intended to be limiting, and any suitable wiring combination for emitter 1604 is contemplated and encompassed herein.

[0108] 17A is a conceptual diagram and FIG. 17B is a cross-sectional view illustrating an IVL device 1700 having an array of optical-based pressure wave emitters 1702A-1702C (e.g., emitter array 112 of FIG. 1). As used herein, optical-based emitter 1702 can include the distal ends or distal portions of respective optical fibers or tubes 1704A-1704C, which the IVL device 108 of FIG. 1 can include in addition to or instead of one or more electronic emitter units, as described above.

[0109] According to some non-limiting examples, the optical fiber 1704 can deliver, for example, approximately 20-100 millijoules of energy within approximately 1 millisecond to the inflation fluid 408, such as water, a saline / contrast mixture, another fluid, or a combination thereof, within the interventional balloon 110 to generate and propagate a high-energy pressure wave. However, these values ​​are merely exemplary, and the amount of energy and / or time can be tailored to a particular clinical application. In some examples, the emitted light pulse width (e.g., the duration of the emitted light) can be 5 nanoseconds or longer.

[0110] Based on various clinical needs, the IVL device 1700 can include any suitable number of optical fibers 1704. In some examples, the IVL device 1700 is configured to transmit a laser signal having a wavelength between about 1064 nanometers (nm) and about 1460 nm, although shorter wavelengths may be effective as well. Exemplary diameters of the optical fibers 1704 can range from about 50 microns or less to about 200 microns or more, depending on the particular clinical application.

[0111] As shown in FIG. 17A , in some examples, the distal emitter portion 1702A of the optical fiber 1704A may be oriented at a predetermined angle “θ” relative to the central longitudinal axis 116. For example, to protect the inner extension structure 318, the distal emitter portion 1702A may be oriented at an angle θ greater than 90 degrees, such as greater than about 114 degrees (e.g., greater than about 24 degrees) from a normal tangent. In the case of the optical fiber 1704A, only the distal-most surface or end of the emitter portion 1702A is angled away from the inner extension structure 318. In other examples, such as the example of the optical fiber 1704B, the entire distal portion 1702B may be bent or angled away from the inner extension structure 318. In some such examples, the optical fiber distal portion 1702B may diverge by an angle “φ” between about 0 degrees and about 24 degrees.

[0112] The optical emitters 1702 of the optical fibers 1704 can emit and deliver high-energy pressure waves circumferentially around the inner elongated structure 318 (e.g., as shown in FIG. 17B ), or longitudinally along the inner elongated structure 318, or a combination thereof. For example, the optical fibers 1704 can be adjacent to the inner elongated structure 318 (e.g., 1704A) for circumferential lesion treatment, or radially off-center (e.g., 1704B) for non-circumferential lesion treatment. Some exemplary advantages of using two or more optical fibers 1704 include reducing the overall cross-sectional profile of the IVL device 1700 by positioning the optical fibers 1704 around the proximal portion of the catheter's elongated body 106 ( FIG. 1 ). Additionally, more optical fibers 1704 allow for more controlled pressure waves. In addition to directing energy based on where the optical fibers 1704 are positioned around the IVL catheter 104, the size of the cavitation bubbles may be controlled based on the selected diameter (e.g., cross-sectional area) of the optical fibers 1704. These optical fibers 1704 may be activated individually or simultaneously based on the need for treatment, allowing, for example, a single IVL device 108 that can treat both circumferentially calcified lesions as well as nodular calcified lesions.

[0113] 18 is a cross-sectional view of an exemplary IVL device 1800 (e.g., IVL device 108 of FIG. 1) having an interventional balloon 1810 (e.g., balloon 110 of FIG. 1) with a multi-layer construction for improved durability. As shown, balloon 1810 can have an outer layer 1802 and an inner layer 1804 for reinforcement purposes. One or both of the reinforcement layers 1802, 1804 can comprise a separate extrusion that covers the top of balloon 1810, with another layer covering the top of this pressure-retaining layer.

[0114] The example shown in FIG. 18 represents one of several solutions to the potential risk of balloon rupture. For example, balloon 1810 may be formed from a single multi-layer extrusion, with the balloon's outer, thinner, more flexible layer 1802 being softer and less prone to tearing than the inner, high-pressure, inflexible (or "less pliable") retention layer 1804. For example, one exemplary construction may include a high-pressure inner retention layer 1804 that comprises 70% to 100% of the balloon wall thickness, such as nylon-12 or Pebax-72D. The outer layer 1802 is made from a more flexible substance such as urethane, Pebax, or any other suitable material with a medium-to-low durometer measurement, for example, about 63D or less.

[0115] Another solution is to form the balloon from two separate extrudates 1802, 1804, e.g., a separate extrudate layer 1802 on the outer surface of an inner non-compliant or semi-compliant balloon 1804. Another solution is to form the balloon 1810 from a thin polymer inner layer 1804 covered by a reinforcing layer 1806, such as a polymer fiber such as aramid or UHMWPE, with a top coating 1802 for encapsulating the fibers. The outer layer 1802 may, as one non-limiting example, have multiple reinforcing layers, e.g., a set of 16 braided fibers and 4 to 8 longitudinal fibers (inclusive). Other variations in braid patterns, such as those containing 32 fibers or 48 fibers, are also feasible. Additionally, the reinforcing fibers may be arranged in an orthogonal weave pattern, such as a mesh sheet cut into strips, as opposed to (or in addition to) being braided directly onto the balloon 1810.

[0116] Although not shown in FIG. 18 , another solution to potential balloon rupture is to coat the balloon with an abrasion-resistant coating, such as the outer coating 326 of FIG. 3 . This solution can be achieved by applying the coating to the balloon 1800 by dipping, spraying, or roll-casting. According to some examples, this coating may be or include a polymer, such as urethane, parylene, silicone, or thermoplastic polyurethane (TPU). These coatings may enable the balloon 1810 to maintain high pressures while protecting the balloon structure from damage due to contact with calcified lesions within the target vessel. Although not shown, another technique involves implementing a compliant balloon body to allow for conformance to plaque and puncture resistance. In an example of this solution, non-compliant cones are implemented on either end of the balloon to prevent pressure waves from propagating proximally or distally to the balloon 110.

[0117] 19 and 20 show two exemplary IVL devices 1900, 2000, respectively, having an interventional balloon 110 with a protective structure 1902, 2002, or "protective cage." Specifically, FIG. 19 is a profile view of a first exemplary IVL device 1900 having a first such protective structure 1902, and FIG. 20 is a side view of a second exemplary IVL device 2000 having a second such protective structure 2002.

[0118] These protective structures 1902, 2002 are configured to provide similar rupture protection to the more continuous balloon outer layer or coating 1802 described above with respect to Figure 18. According to any of these examples, the balloon 110 can have a cage-like structure thereon, thereby reducing direct physical contact (e.g., friction) between the outer surface of the balloon and calcified plaque lesions attached to the vessel wall.

[0119] The cage-like structure 1902, 2002 may be or include a metal, such as SST or Nitinol, or a polymer. In a multiple nested layer balloon (e.g., balloon 1800 of FIG. 18 ), the protective structure 1902, 2002 can be disposed between the outer balloon layer 1802 and the inner balloon layer 1804. In some examples, the cage-like structure 1902, 2002 includes multiple longitudinal members, e.g., extending parallel to the central longitudinal axis 116. In some such examples, the protective structure 1902, 2002 may be selected to include an odd number of longitudinal members, such as three or five longitudinal members, to facilitate rewrapping of each balloon prior to removal of the IVL device 108 from the patient's vasculature. These longitudinal members or bars may be interconnected as a stent-like structure, such that the structure has a predetermined size and shape that does not change (or changes only a relatively small amount) during inflation of the balloon 110.

[0120] According to some examples, the protective structures 1902, 2002 are rigidly bonded to the outer surface of the balloon 110. In some such examples, the protective structures 1902, 2002 are rigidly bonded to the proximal and distal end portions of the balloon 110, but are not bonded to the longitudinal central balloon portion.

[0121] The example of Figure 19 shows a less comprehensive protective structure 1902 compared to the exemplary protective structure 2002 of Figure 20. For example, protective structure 1902 includes, by way of non-limiting example, two (upper and lower) longitudinal elements 1904 and approximately thirteen circumferential elements 1906. In comparison, protective structure 2002 is shown to include a more continuous wire mesh or window screen configuration having tens or hundreds of interwoven longitudinal and circumferential elements.

[0122] 21 illustrates an exemplary IVL device 2100 (e.g., IVL device 108 of FIG. 1) that includes a pair of creasing members 2102A, 2102B. The creasing members 2102 are configured to physically contact the inner surface of a calcified plaque lesion and abrade it (e.g., through friction applied over a substantially small surface area corresponding to a substantially high stress pressure at that point), helping to fragment and break up the lesion.

[0123] In some examples, the creasing member 2102 may be coupled to a protective structure within or on the balloon 110 (e.g., protective cages 1902, 2002 in FIGS. 19 and 20, respectively). In some examples, the balloon 110 may include a single creasing member 2102. In other examples, multiple creasing members 2102 may be rotationally symmetrically or asymmetrically distributed around the circumference of the balloon 110. During an IVL procedure, the balloon 110 may be rotated circumferentially to apply specific creasing members 2102 to the calcified lesion. In some examples, the creasing member 2102 may be formed from a metal such as SST or a nickel-titanium alloy (e.g., Nitinol), a metal wire, a printed metallic ink (which may contain a very small amount of polymer binder from processing), tungsten, or a polymer.

[0124] In some examples, such as the example shown in Figure 21, the creasing member 2102 can include a generally flat or planar outer surface. In other examples, the creasing member 2102 can include a toothed or serrated outer surface, for example, to increase dynamic friction when contacting a calcified plaque lesion.

[0125] 22 illustrates an exemplary IVL device 2200 (e.g., IVL device 108 of FIG. 1) including a fragmentation element 2202 configured to aid in fragmenting calcified plaque lesions during an IVL procedure. As shown in FIG. 22, the fragmentation element 2202 includes an elongated conductive wire 2204 and a plurality of piezoelectric elements 2206 distributed longitudinally along the wire 2204.

[0126] The fragmentation element 2202 provides at least two advantages. First, when the conductive wire 2204 is aligned against a calcified plaque lesion, the narrow cross-sectional area of ​​the conductive wire 2204 substantially increases the pressure applied to the lesion along the axis of the wire, allowing the clinician to control the specific location where the lesion begins to fragment. Second, when an alternating current (AC) is applied through the conductive wire 2204, the piezoelectric element 2206 is configured to rapidly expand and contract, thereby generating additional pressure waves that are focused directly against the outer surface of the lesion.

[0127] In some examples, the disruption element 2200 includes a distal protection element, such as an embolic protection element, as described further below with respect to FIG. 24 . For example, the distal protection element may be coupled to a distal portion of the conductive wire 2204. In addition to, or alternatively to, the wire 2204, the disruption element 2200 may include a braided layer, such as a nitinol braid. The piezoelectric element 2206 may be firmly bonded to the outer surface of the braid, and the braid may be bonded to the outer surface of the balloon 110. This braid may perform a similar function as described above with respect to the wire 2204.

[0128] FIG. 23 illustrates an IVL device 2300 (e.g., the IVL device 108 of FIG. 1) having an exemplary spring mechanism 2302. In some previous devices, the interventional balloon 110 can be difficult to insert into and remove from an introducer sheath (not shown) during an IVL procedure. This can be caused, for example, by excessively bulky proximal and / or distal balloon cones (e.g., compared to the distal balloon cone 1404 of FIG. 14A ) or a lack of effective folding or wrapping of the balloon 110 during and / or after deflation. In some instances, this problem can be addressed by reducing the radial profile (e.g., cross-sectional area) of the balloon while it is in an uninflated or deflated state. This can be accomplished by longitudinally stretching the balloon 110 while coupling its proximal and distal ends to an inner elongated structure 318.

[0129] Another technique for reducing the profile of the balloon 110, illustrated in FIG. 23, is to incorporate a spring 2302 within the inner elongated structure 318. The spring 2302 should be longitudinally compressed when coupled to the inner elongated structure 318 (e.g., at the proximal end 2304A and distal end 2304B). The balloon 110 may then be bonded to the inner elongated structure 318 such that when the spring 2302 is allowed to expand back to its resting length, the inner elongated structure 318 and balloon 110 similarly expand along the longitudinal direction 116 and compress radially inward. The balloon 110 may also be longitudinally stretched around the tube 318 during the bonding process (as described above) to further facilitate this technique. During inflation, the balloon 110 still expands to its preformed shape, while the inner elongated structure 318 compresses slightly along the longitudinal direction. That is, the proximal and distal points where balloon 110 is coupled to inner elongate structure 318 may compress slightly toward each other as balloon 110 expands radially outward.

[0130] Another technique for reducing the cross-sectional profile of the balloon 110 is to improve the balloon's re-wrapping after deflation during the procedure. This can be achieved in several ways, such as by incorporating or embedding multiple longitudinal wires within the balloon body. These longitudinal wires can help define pleats or predetermined fold locations for the balloon 110 rather than allowing the balloon material to "bundle" randomly. While any number of longitudinal wires can be incorporated, an odd number of longitudinal wires can help prevent the balloon from collapsing into a plane of symmetry, such as a "paddle" or "pancake" configuration of the balloon. Additionally, the longitudinal members may be radiopaque so that they can be used to visualize the inflated balloon 110 and its apposition to the vessel wall during the IVL procedure. Such a configuration can eliminate the need for a separate fluid contrast agent, thereby potentially shortening the overall duration of the IVL procedure. In some examples, these longitudinal wires can be made of metal wires (e.g., flat, round, or irregularly shaped such as pentagonal), printed inks (e.g., metallic or polymer inks), or polymer structures.

[0131] FIG. 24 illustrates an exemplary IVL device 2400 (e.g., the IVL device 108 of FIG. 1) including a distal protection device 2402. According to some examples, the distal protection device 2402 may be positioned at a distal end portion of the IVL device 2400. In some examples (but not all examples), the distal protection device 2402 includes an elongated element 2404 (e.g., a guidewire) extending through, for example, the guidewire lumen 322 of the inner elongated structure 318, and a distal expandable member 2406. In some such examples, the expandable member 2406 extends distally outward from the distal port 324 and is configured to expand radially outward to the expanded configuration shown in FIG. 24. The inner lumen 322 of the inner elongated structure 318, which surrounds the expanded distal protection device 2402, may accommodate a 0.010 inch to 0.035 inch guidewire. Thus, the size of the guidewire lumen can range from 0.011 inches to 0.038 inches to allow free movement of the guidewire.

[0132] The distal protection device 2402 is configured to capture calcification particles generated during the IVL procedure. The expandable member 2406 may include a basket frame design, as shown in FIG. 24 , although other suitable designs are also contemplated. In some such examples, the basket frame 2406 may be or include a nitinol cut tube (similar to a stent) or a nitinol wire frame. The material comprising the basket 2406 may be a thin polymer or fiber mesh with ablated holes. According to some examples, the basket frame 2406 may be positioned outside the balloon catheter 104, with the distal protection member shaft 2404 designed to accommodate balloon expansion (the balloon 110 pushing up the shaft 2404 of the filter device 2402).

[0133] The distal protection device 2402 can also be rapidly exchanged on the balloon catheter 104. The rapid exchange port may be proximal to the balloon 110 or distal to the balloon 110. The distal protection device 2402 can enter and exit the balloon catheter at the hub 306 (FIG. 3), proximal to the balloon 110, or distal to the balloon 110. This distal protection device 2402 may also be modular in nature (e.g., removable), such that it is only present on the IVL device 2400 when needed for the procedure.

[0134] FIG. 25 shows an example of the IVL system 100 of FIG. 1 including a closed-loop energy delivery feedback mechanism. In some current IVL systems, the amount of energy delivered is fixed and not adjusted to clinical need. The present disclosure enables automated delivery of energy based on a presented clinical scenario to improve treatment efficacy and efficiency, for example, via sensors 2502 measuring fluid pressure, fluid volume / velocity, and / or temperature. Any combination or use of the monitoring provided by the controller as disclosed herein can provide input for determining the maximum pressure wave intensity and / or heat level generated by the emitter.

[0135] According to some examples, the system 100 may include one or more sensors 2502, for example, integrated within the energy generator 102, the catheter 104, or both. Based on data received from the sensors 2502, the system 100 (e.g., processing circuitry of the generator 102 or a separate computing device associated with the system 100) is configured to dynamically (e.g., in real time) adjust the energy level output by the generator 102.

[0136] For example, sensor 2502 may include, by way of non-limiting example, an inflation fluid flow rate monitor, an inflation fluid pressure monitor, a vessel wall surface monitor, a vessel diameter monitor, a balloon diameter monitor, a plaque fragmentation monitor, or any other type of sensor configured to provide insight into the current progress of an IVL procedure. In some examples, sensor 2502 is configured to detect the resonant frequency (e.g., natural frequency or harmonic frequency) of calcium within the lesion.

[0137] Based on real-time monitoring of sensor data from sensor 2502, system 100 may be configured to dynamically adjust one or more of the current level, voltage level, electrical pulse duration or frequency, light intensity, light pulse duration, light pulse frequency, or any other suitable parameters that affect the amount or rate of energy delivered via emitter array 112. In the particular example of plaque-lesion resonant frequency, system 100 may be configured to automatically adjust the emitter acoustic frequency to match the detected resonant frequency of the lesion in order to more effectively fragment the lesion.

[0138] In some examples, in addition to or alternatively to dynamically adjusting the energy level, the system 100 is configured to automatically terminate the applied voltage in response to certain conditions being met, including (but not limited to) a threshold fragmentation of the calcified plaque lesion being achieved or a detected system parameter being outside a threshold level (e.g., suspected malfunction of the balloon 110 or another component).

[0139] As one illustrative example, the IVL system 100 may be configured to monitor the fluid pressure of the balloon 110. For example, the sensor 2502 may include a pressure transducer configured to interface with the inflation lumen 320. Accordingly, the system 100 may further include a three-way fluid connector (e.g., the catheter hub 306 of FIG. 3 ) configured to fluidly couple the inflation syringe (e.g., the inflation port 310), the inflation lumen 320, and a pressure line returning to the energy generator 102. The pressure transducer may be integrated into the energy generator 102 and fluidly coupled along the pressure line. In some such examples, the fluid line may also include a transducer protector, such as a valve or membrane, configured to prevent the inflation fluid 408, e.g., a saline / contrast fluid mixture, from entering components of the energy generator 102.

[0140] As another illustrative example, IVL system 100 (e.g., processing circuitry of energy generator 102 or another computing device associated with system 100) may be configured to monitor the electrical impedance of one or more components of system 100. When plasma is generated in spark gap 404 between electrode pair 402 (FIG. 4), the local electrical impedance drops, and thus system 100 (upon detection) terminates the applied voltage. Additionally or alternatively, system 100 (e.g., measurement unit 216 of FIG. 2) may be configured to monitor the current level generated by generator 102 as it is output and automatically terminate the applied voltage in response to a change in the monitored current above a threshold.

[0141] In other examples, rather than dynamically modifying energy levels (e.g., applied voltage levels, etc.), system 100 may be configured to apply energy levels (e.g., voltage levels) as "all or nothing" (e.g., binary 0 or 1). For example, system 100 may transmit energy at a predetermined level through catheter 104 only while certain conditions are determined to be met, as indicated by data from sensor 2502. Additionally or alternatively, system 100 may be configured to adjust other parameters. For example, system 100 may be configured to dynamically adjust the longitudinal length and / or inflation diameter of balloon 110 as needed.

[0142] Figure 26 shows an exemplary handle 2600 that may be coupled to the proximal portion 302 (Figure 3) of the IVL catheter 104 of Figure 1. The catheter 104 may include the handle 2600 in addition to, or instead of, the catheter hub 306 (Figure 1). When both the hub 306 and the handle 2600 are present, the handle 2600 may be coupled to a portion of the elongated body 106 that extends proximally through the hub access port 308.

[0143] Existing IVL catheters require expensive generators to power the catheter. In the example shown in FIG. 26 , a catheter handle 2600 includes an integrated power source 2602. The power source 2602 may include a battery, a capacitor, or any other suitable integrated power source configured to deliver a power level sufficient to operate the emitter array 112 ( FIG. 1 ). That is, in some examples, the system 100 ( FIG. 1 ) may include the handle 2600 in place of the energy generator 102. In other examples, the handle 2600 may be configured to provide supplemental or auxiliary power to the emitter array 112. In some examples, the catheter 104 may be configured to removably couple to the energy generator 102 and function while connected or disconnected, similar to a laptop or other mobile device.

[0144] Typical IVL systems and devices are configured to emit high-energy pressure waves that propagate across all spatial dimensions. This attribute can be relatively effective, for example, on ring-shaped calcified plaque lesions that appear around the entire inner circumference of a vessel wall. However, other lesion configurations may not be effectively treated or, alternatively, may waste significant amounts of energy due to inefficient application of energy. Accordingly, several features and techniques are disclosed herein that enable an IVL device 108 (FIG. 1) to focus the emitted high-energy pressure waves in a specific spatial direction or a limited range of directions.

[0145] For example, FIG. 27 is a cross-sectional view of an IVL device 2700 (e.g., IVL device 108 of FIG. 1) having a first exemplary wave director 2702. In some examples, the wave director 2702 includes a layer of material oriented along only a portion of the inner circumference of the balloon 110 and extending longitudinally (e.g., proximally and distally) through the balloon 110. The material is configured to substantially absorb and / or reflect pressure waves that contact the material, thereby reducing energy wasted by being directed in any direction. As described above, this acoustically opaque material can include, for example, ceramic, porcelain, diamond, polyimide, polyetheretherketone (PEEK), similar materials, or any suitable combination thereof.

[0146] 27, the waveguide 2702 is shown as having a half-moon shaped cross-sectional profile, although other configurations are contemplated. For example, the waveguide 2702 may define a substantially semicircular cross-sectional profile, or alternatively, may include a relatively thin reflective layer coated on a portion of the interior surface of the balloon 110.

[0147] In some examples, the director 2702 includes a separate lumen "pocket" 2704 that can be inflated or deflated as needed in a typical balloon angioplasty procedure. In some examples, the fluid pocket 2704, separate from the inflation lumen 320 (FIG. 3), is configured to deliver gas to inflate the pocket 2704 so as not to interfere with the inflation of the balloon 110 itself. During use of the IVL device 2700, pressure waves emanating from the spark gap 404A are unable to penetrate the fluid pocket 2704 and are therefore absorbed and / or reflected in the opposite circumferential direction.

[0148] In addition to, or alternatively to, an absorbent and / or reflective material, the director 2702 of FIG. 27 may be or include at least one of the pair of electrodes 402 (FIG. 4) of the electron emitter unit 400. For example, a half-moon shaped director 2702 may include one or both of the electrodes 402 to directionally focus the emitted pressure waves to fragment the target calcification. In examples where the director 2702 includes both a reflective material and one or both electrodes 402, the electrodes 402 may be positioned radially inward from the reflective material, which may be adhered to the inner surface of the balloon 110.

[0149] In addition to, or alternatively to, reflective materials, in some examples, the compositional material of balloon 110 can be strategically varied to provide directionally targeted wave emission. For example, the material of balloon 110 can be configured to be thicker along some portions of its circumference than along other portions. In some examples, balloon 110 may incorporate a more transmissive material along a first portion of its circumference and a more absorbent and / or more reflective material along a second portion of its circumference.

[0150] In some examples, a fluoroscopy wire (e.g., a conductive wire 2204 as described above with respect to FIG. 22) or other visual indicator 2704 can be positioned on the opposite side of the director 2702. The visual indicator 2704 helps the clinician orient (e.g., rotate) the IVL device 2700 toward the target calcification before initiating targeted fragmentation. Also, as described above with respect to FIG. 22, in some examples, the piezoelectric element 2206 can be mounted or extended at an off-center location (e.g., asymmetrically distributed) on or within the balloon 110 to provide increased energy on that side. In such examples, the tissue region adjacent to the piezoelectric element 2206 receives a greater amount of energy, thus enabling directional targeted lesion fragmentation.

[0151] 28A is a perspective view and FIG. 28B is a cross-sectional view of a second exemplary directionally focusing IVL device 2800 (e.g., IVL device 108 of FIG. 1). The IVL device 2800 includes an array of emitter assemblies 2814, each of which includes two or more individual emitter units 2816 circumferentially distributed around an inner elongated structure 318. Each individual emitter unit 2816 can include an electrode pair, a piezoelectric element, or an optical emitter.

[0152] 28A and 28B, the emitter units 2816 may be configured to be mounted or expanded at off-center locations within the cross-sectional area of ​​the balloon 110, thereby resulting in increased energy delivered to each side of the balloon 110. In some examples, each individual emitter unit 2816 is configured to be independently actuatable. In other examples, all of the individual emitter units 2816 of different emitter assemblies 2814 aligned along a common longitudinal axis are configured to be commonly actuatable. Additionally or alternatively, the individual emitter units 2816 can be configured to be tilted or angled toward and away from the inner elongated structure 318 when mounted on the stalk 2818 to further control directional energy transmission.

[0153] 28A and 28B, the IVL device 2800 can also include one or more radiopaque visual indicators 2704 to aid in device orientation relative to the target treatment site. However, as shown in FIG. 28B, the visual indicators 2704 should be asymmetrically distributed around the circumference of the balloon 110 to prevent ambiguous balloon orientation.

[0154] 29A is a perspective view and FIG. 29B is a cross-sectional view of a third exemplary directionally focusing IVL device 2900 (e.g., IVL device 108 of FIG. 1). IVL device 2900 is an example of IVL device 2800 of FIG. 28, except for differences described herein. In particular, interventional balloon 110 of IVL device 2900 includes two or more elongated sub-balloons 2902 circumferentially distributed around inner elongated structure 318. Each sub-balloon 2902 is configured to hold a subset of emitter units 2816 oriented along a common longitudinal axis. Each emitter unit subset is configured to be independently operable from the other emitter unit subsets, and each sub-balloon 2902 is configured to serve to apply emitted pressure waves to a specific portion of the circumference of the inner surface of the target vessel.

[0155] In some examples, each sub-balloon 2902 is configured to be individually inflatable, for example, according to a different inflation rate or amount than the other sub-balloons. In this manner, the IVL device may be positioned off-center toward a particular portion of the vessel wall (e.g., a calcified lesion). Such examples allow each subset of emitter units 2816, including corresponding creasing members 2102 (FIG. 21), if present, to be positioned closer to the target treatment site.

[0156] As described above, the emitters 2618 can be angled away from the inner elongated structure 318 and closer to the inner radial wall of the balloon 110 (e.g., instead of adjacent to the inner elongated structure 318). Thus, the energy delivered by these emitters 2816 can be more focused on the wall of the vessel to which they are positioned closest. This, in combination with a cutting wire (e.g., the conductive wire 2204 of the fragmentation element 2202 in FIG. 22), can create a high stress focal point to more efficiently and / or effectively fragment nodular calcified lesions.

[0157] 28A and 29B, the energy generator 102 (FIG. 1) can independently and selectively control emitters 2816 present around the circumference of the IVL device 2900. This means that energy delivery can be controlled by firing only the emitters 2816 closest to the calcified lesion, without tilting or moving the emitters 2816 in any way. Additionally, if the treatment being offered requires full-circumference energy delivery, all emitters 2816 may still be fired, allowing a more traditional style of treatment to occur.

[0158] Note that these emitters 2816 can all be located within the same balloon 110, as shown in Figures 28A and 28B, or within their own separate sub-balloons 2902, as shown in Figures 29A and 29B. Additionally, while the relative alignment shown in Figures 28B and 29B allows for only one array of emitter units, note that these emitters 2816 can be placed around the catheter throughout the entire balloon 110, with the amount of emitters possible being determined only by the length of the balloon 110 being used.

[0159] FIG. 30 shows a front view of a flattened hypotube 3000. While the hypotube 3000 may actually be cut into its oval shape, it is useful to view the hypotube 3000 in this flattened state to illustrate the geometry of the struts 3002 and cut-out portions. For example, in this view, it is clear that the cut-out portions of the hypotube 3000 form parallelograms 3006. While the use of parallelograms 3006 is not required, it is a practical and simple shape to cut from a three-dimensional object (such as a rolled hypotube). Additional shapes, such as chevron patterns, are also contemplated. Cutting these parallelograms 3006 forms struts 3002 between two separate sections of the hypotube 3000 (which become electrodes, as described in FIGS. 33A, 33B, and 34). These struts 3002 bridge the gaps between these sections of the hypotube 3000, providing structure and keeping the hypotube 3000 together during mounting onto the elongated body. The gaps that these struts 3002 bridge become spark gaps 3004 when the struts 3002 are removed.

[0160] For purposes of this disclosure, the hypotube and spark gap will be referred to as elliptical, but it should be understood that ellipses encompass a subset of the shape known as circles. An ellipse is defined as having a major axis and a minor axis, and a circle is a special case where the major and minor axes are equal in length. Thus, any recitation of an ellipse throughout this disclosure also includes a recitation of a circle.

[0161] FIG. 31 is a perspective view of a laser cut oval hypotube 3100. As can be seen, the laser cut oval hypotube 3100 may include struts 3102. FIG. 31 shows three struts 3102, similar to the flattened view of the hypotube 3000 in FIG. 30. However, it should be noted that any desired number of struts 3102 may be included without departing from this disclosure. According to some examples, the laser cut oval hypotube 3100 is formed into its oval shape prior to the laser cutting process. In this manner, fewer cuts may be required to form the struts 3102.

[0162] The flat design, as shown in Figure 30, represents the cutting pattern used by the laser on the hypotube. The hypotube is mounted in the laser cutter with the laser pointing radially inward toward the center of the tube. The tube and laser are then rotated and translated relative to one another so that the pattern is wrapped around the circumference of the tube, thus forming the laser cut hypotube 3100.

[0163] Figure 32A is a perspective view and Figure 32B is a side view of the laser cut oval hypotube 3200 (likely the laser cut oval hypotube 3100 of Figure 31) as it might appear after being placed on the elongated body 3204 (or stated differently, after the elongated body 3204 has been inserted into the laser cut oval hypotube 3200). Here, the struts 3202 (only one is shown in Figures 32A and 32B because the elongated body 3204 blocks the view of any remaining struts) are still present within the laser cut oval hypotube 3200 and, in some instances, will remain in place until the laser cut oval hypotube 3200 is adhered to the elongated body 3204.

[0164] 33A is a perspective view and FIG. 33B is a side view of an electron emitter 3300 as it may appear after removal of the hypotube struts. The electron emitter 3300 may include a first electrode 3302 and a second electrode 3304 separated by a longitudinal spark gap 3306. The first electrode 3302 and the second electrode 3304 may be disposed on an elongated body 3308, and the longitudinal spark gap 3306 may be longitudinal relative to the elongated body 3308. In some examples, the first electrode 3302 includes a first periphery 3310 that faces the longitudinal spark gap 3306, and the second electrode 3304 includes a second periphery 3312 that also faces the longitudinal spark gap 3306. The first perimeter 3310 may be parallel to the second perimeter 3312, allowing the longitudinal spark gap 3306 to also be an elliptical spark gap. According to some examples, this allows sparks to arc from the first electrode 3302 to the second electrode 3304 randomly around the first perimeter 3310.

[0165] FIG. 34 is a side view of a pair of electron emitters as they may appear in use. As seen in FIG. 34, multiple electron emitters, including a first electron emitter 3400 and a second electron emitter 3414, may be used together in an IVL device. As described above in FIGS. 33A and 33B, the first electron emitter 3400 may include a first electrode 3402 and a second electrode 3404 separated by a first longitudinal spark gap 3406. The first electrode 3402 and the second electrode 3404 may be disposed on an elongated body 3408, and the first longitudinal spark gap 3406 may be longitudinal relative to the elongated body 3408. For purposes of this disclosure, it should be understood that the longitudinal spark gap 3408 refers to a direction transverse to the arc discharge that is formed. The spark gap may also be considered an elliptical or circumferential spark gap because an arc can form at any point around the circumference of the electrode. The first electrode 3402 may include a first periphery 3410 facing the first longitudinal spark gap 3406, and the second electrode 3404 may include a second periphery 3412 also facing the first longitudinal spark gap. In some examples, the first periphery 3410 is parallel to the second periphery 3412, allowing the first longitudinal spark gap 3406 to also be an elliptical spark gap. This may allow a spark to arc randomly from the first electrode 3402 to the second electrode 3404 around the first periphery 3410.

[0166] Similarly, the second electron emitter 3414 may include a third electrode 3416 and a fourth electrode 3418 separated by a second longitudinal spark gap 3420. The third electrode 3416 and the fourth electrode 3418 may be disposed on the elongated body 3408, and the second longitudinal spark gap 3420 may be longitudinal relative to the elongated body 3408. The third electrode 3416 may include a third perimeter 3422 facing the second longitudinal spark gap 3420, and the fourth electrode 3418 may include a fourth perimeter 3424 that also faces the second longitudinal spark gap 3420. According to some examples, the third perimeter 3422 is parallel to the fourth perimeter 3424, allowing the second longitudinal spark gap 3420 to also be an elliptical spark gap. This may allow a spark to arc from the third electrode 3416 to the fourth electrode 3418 randomly around the third periphery 3422 .

[0167] The first perimeter 3410, second perimeter 3412, third perimeter 3422, and fourth perimeter 3424 may all be parallel to one another, although this is not strictly necessary. Additionally, while only a first electron emitter 3400 and a second electron emitter 3414 are shown, it will be understood that as many electron emitters as can fit within the IVL device can be used, if desired.

[0168] Additionally, the electron emitters may be separately wired. For example, a first ground wire may be welded to the first electrode 3402, and a second ground wire may be wired to the third electrode 3416. A common power wire may be wired to both the second electrode 3404 and the fourth electrode 3418. This configuration is similar to the multiple parallel wire configurations discussed in FIGS. 15A, 15B, and 16A. In this manner, the first electrode 3402 and the third electrode 3416 may be individually powered, allowing for selective firing of the electron emitters, while still limiting the number of wires required by grounding all the electron emitters together. As noted above, there may be more than one electron emitter in the present invention, and this individual powering and group grounding of the electron emitters may be utilized with any desired number of electron emitters. It should be understood that due to the nature of the parallel circuitry, the described configuration can be achieved by reversing the power and ground wires so that there is an individual power wire for each electrode and a common ground wire, as illustrated in Figures 15A and 15B.

[0169] FIG. 35A is a cross-sectional view of an IVL device including an electron emitter 3500. As shown in FIG. 35A, the IVL device includes an "inner" portion and an "outer" portion. The electron emitter 3500 is part of the outer portion and is non-adjacent to the guidewire lumen 3512. The electron emitter 3500 may be welded to a wire 3506a (shown here as a flat or rectangular wire), and this subassembly is then adhered to the inner portion via a layer of adhesive 3502 (e.g., a potting material). The inner portion may be a stack of copolymer 3504a, reinforcement material 3508, and polyimide 3510, which form the elongate body of the catheter in which the electron emitter 3500 resides. While the inner portion is described as this stack of copolymer 3504a, reinforcement material 3508, and polyimide 3510, it is understood that additional components may be used or components may be omitted. For example, in some examples, the inner portion does not include a reinforcement 3508, such as the example shown in Figure 35B. In additional examples, the inner core includes a polyimide / polytetrafluoroethylene (ptfe) blend to improve lubricity at the inner radius of the device.

[0170] In examples including a layer of reinforcement 3508, the reinforcement 3508 may be a non-metallic material such as polyetheretherketone (PEEK). In other examples, the reinforcement 3508 may be made from Kevlar® fibers. In yet other examples, the reinforcement 3508 may be made from high density polyethylene fibers. These high density polyethylene fibers may be metallic or non-metallic. The reinforcement 3508 may also be electrically conductive.

[0171] FIG. 35B shows an additional cross-sectional view of electron emitter 3500. Electron emitter 3500 is part of the outer portion and is not adjacent to guidewire lumen 3512. Alternatively, electron emitter 3500 can be welded to wire 3506b (shown in FIG. 35B as a rounded wire, as opposed to the flat wire illustrated by FIG. 35A), which is then adhered to the inner portion via a layer of adhesive 3502 (e.g., potting material). FIG. 35B shows the inner portion made solely of a stack of polymer 3504b and polyimide 3510. It is further understood that copolymer 3504a and polymer 3504b are synonymous. In some examples, polyimide 3510 is a doped polyimide. This doped polyimide may be non-metallic.

[0172] Figure 36 is a cross-sectional view of a spark gap. Some IVL devices use two-point electrodes to generate the arc that creates the cavitation bubbles. In these devices, the arc repeatedly recurs between the same two points. Each arc causes degradation at the location of the spark. Over time, this repeated degradation at a single location can lead to emitter failure, limiting the life of the device.

[0173] FIG. 37 is a cross-sectional view of an elliptical spark gap 3700 as disclosed in the present invention. This elliptical spark gap 3700 allows arcing to form anywhere around the circumference of the electrode. This arcing may be randomly perpetuated around the circumference of the electrode and tend to occur where degradation is least. Because the arcing is not limited to a specific point (both generation and ground), associated degradation at any one location may accumulate more slowly, increasing the number of pulses before emitter failure. This may increase the average lifespan of the IVL device and therefore minimize the number of replacements required. Additionally, this may increase the number of pulses a clinician can deliver. This random arcing location may also provide a more consistent delivery of acoustic pressure over the course of delivery. The non-directional nature of cavitation means that this random firing may also provide a more uniform treatment field in the circumferential direction.

[0174] FIG. 38A is a conceptual diagram illustrating a first wiring configuration 3800A of an emitter array 3802 having two electrode pairs 3804, and further illustrates parallel wiring configurations such as those shown in FIGS. 15A, 15B, and 16A. Like these previous figures, FIG. 38A shows electrode pairs 3804 wired according to the "n+1" wiring configuration described above, but wired in parallel. In some examples, such as in the schematic diagram of FIG. 38A, the first electrode pair 3804A receives a first ground wire 3806A and the second electrode pair 3804B receives a second ground wire 3806B. These power wires 3806 are coupled to the respective electrode pairs 3804 by means such as welding. Both the first electrode pair 3804A and the second electrode pair 3804B are coupled to the same power wire 3808. In this manner, the first electrode pair 3804A and the second electrode pair 3804B can be independently powered. Exemplary advantages of this parallel wiring configuration include the ability to carry higher currents across each electrode pair 3804. Additionally, because each electrode pair 3804 is individually powered, each electrode pair 3804 can also be individually actuated (or "fired"). In some examples, the parallel wiring configuration reduces the overall resistance of the IVL system because individually powering one electrode pair 3804 can reduce the required number of resistors needed to generate current.

[0175] Figure 38B is a conceptual diagram illustrating a second wiring configuration 3800B for an emitter array 3802 having four electrode pairs 3804, which provides further detail on the wiring configuration shown in Figure 16B. In this second wiring configuration 3800B, a combination of both parallel and series wiring techniques can be implemented, allowing for the benefits of both configurations. For example, a first electrode pair 3804A and a second electrode pair 3804B are connected in series, while the other electrode pairs 3804 are connected in parallel.

[0176] Specifically, such second wiring configuration 3800B allows a clinician to simultaneously activate (1) electrode pair 3804A, 3804D, (2) electrode pair 3804C, 3804D, and (3) electrode pair 3804A, 3804B. For these three examples, it is understood that the use of the terms "ground wire" or "power wire" is not limiting, and that the wires may either not be used in the circuit at all or may be used for purposes other than their descriptive names. As seen in example (1), the "ground wire" may also be a connecting wire, functioning solely as a conduit between the electrode pairs.

[0177] In example (1), power can enter through power wire 3810C, arc across fourth electrode pair 3804D, travel through second connecting wire 3810E to third electrode pair 3804C, arc across third electrode pair 3804C, cross second ground wire 3810B, which is not connected to ground in this example, arc across second electrode pair 3804B, cross first connecting wire 3810D, arc across first electrode pair 3804A, and then complete the circuit through first ground wire 3810A.

[0178] For example, in example (2), power can enter through power wire 3810C, arc across fourth electrode pair 3804D, travel through second connecting wire 3810E to third electrode pair 3804C, arc across third electrode pair 3804C, then bypass second electrode pair 3804B and complete the circuit through second ground wire 3810B.

[0179] Finally, for example, in example (3), power can enter through the second ground wire 3810B (which is not a ground wire in this example), arc across the second electrode pair 3804B, cross the first connecting wire 3810D, arc across the first electrode pair 3804A, and then complete the circuit through the first ground wire 3810A.

[0180] 38B is not intended to be limiting, and any suitable wiring combination for electrode pair 3804 is contemplated and encompassed herein. Additionally, as seen in the example above, electricity can be flowed in either direction through the circuit as desired.

[0181] FIG. 39 is a flowchart illustrating an exemplary technique for forming an emitter assembly for an IVL catheter. Such a method may include (at step 3900) laser cutting an oval hypotube. This laser cutting can create first and second electrodes separated by a longitudinal spark gap. Support posts may remain to support the hypotube until it is in place, but these support posts can be removed later, as described below. It is also important to note that in this step, the hypotube is already oval-shaped before being cut. According to some examples, the method may include (at step 3902) welding a wire to the electrode, allowing the electrode to receive a voltage (via a first wire) that causes an arc to form and then return that voltage to ground (via a second wire).

[0182] In some examples, the method includes inserting (at step 3904) an elongated body through the laser-cut oval hypotube. In this step, the elongated body (i.e., catheter) is inserted into the hypotube, thus placing the hypotube in its correct position. While this step occurs prior to removal of the support structure (i.e., struts), this order is not required, and removal of the support structure may occur prior to placement of the hypotube around the elongated body.

[0183] According to some examples, the method includes (at step 3906) flowing a potting material around the laser-cut oval hypotube. This potting material can maintain the hypotube in place relative to the elongated body. The potting material can be an adhesive. The method can include (at step 3908) removing old support structure. As described above, support posts can be removed to form an oval spark gap around the entire circumference of the electrode. Additionally, this removal of old support structure can separate the electrodes from each other by a predetermined distance.

[0184] In some examples, the method includes (in step 3910) positioning the first electrode and the second electrode to define a longitudinal spark gap therebetween. The spark gap, although defined as elliptical in the previous paragraph, may also be longitudinal. The electrodes may be separated from one another longitudinally around the elongated body, thus creating a spark gap that is longitudinal with respect to the elongated body and elliptical around the circumference of the electrodes.

[0185] 40 is a flowchart illustrating another or further exemplary technique for forming electrodes from a hypotube. In some examples, the method includes (at step 4000) cutting a parallelogram from a central portion of an oval hypotube. While a parallelogram is not strictly necessary as the shape to be cut, it is a practical shape to use due to its symmetry. According to some examples, the method may include (at step 4002) removing support posts. As mentioned above, the old support structure may include support posts that, when removed, allow the two electrodes to be completely separated from each other while maintaining a predetermined distance from each other.

[0186] The method may include (in step 4004) separating the first electrode from the second electrode by a fixed distance around and between the first and second perimeters. The electrodes are separated by removing support posts between the electrodes. If the electrodes are already glued in place (as in FIG. 39 when the potting material is in place), the electrodes maintain this fixed distance from each other. Because the support posts used may all be equal in length, the gap between the electrodes may also be equal around the entire perimeter, thus maintaining a fixed distance between the perimeters of each electrode.

[0187] FIG. 41 is a flowchart illustrating an exemplary technique for wiring electrodes in an IVL catheter. In some examples, the method includes (at step 4100) partially surrounding an elongate body with a laser-cut oval hypotube. While defined as "circular" or "oval" throughout, it should be understood that any shaped hypotube that surrounds the elongate body to any extent, thereby creating a constant distance separation between the electrodes, will create a spark gap that follows the circumference of those electrodes. According to some examples, the method includes (at step 4102) affixing the laser-cut oval hypotube to the elongate body via an adhesive. The adhesive (or potting material, as described above) may maintain the hypotube in position relative to the elongate body and thus prevent the electrodes from moving relative to one another once formed.

[0188] The method may include (at step 4104) welding a power wire to the first electrode. This power wire may be used to supply power to the first electrode, thus generating a spark that can arc to the second electrode, which generates cavitation of gas bubbles. In some examples, the method includes (at step 4106) welding a ground wire to the second electrode. This ground wire may complete a circuit, allowing electricity provided by the power wire to return to ground.

[0189] According to some examples, the method includes extending (in step 4108) a power wire along the elongated body from the first electrode to the hub. The power wire may also be fixed in place along the elongated body to prevent movement. The method may include extending (in step 4110) a ground wire along the elongated body from the second electrode to the hub. Similarly, the ground wire may be fixed in place along the elongated body to prevent movement. While the method describes only one power wire, the use of more electron emitters, and therefore more electrodes, may use either one power wire (wired in series) or multiple power wires (wired in parallel to separate electrodes). The advantages of multiple power wires are discussed above and are discussed again in the method of FIG. 43 below.

[0190] 42 is a flowchart illustrating an exemplary method of using an IVL catheter. In some examples, the method includes (at step 4200) inserting a device into a patient's vascular system. Inserting the device into the patient's vascular system may also include positioning the device at a treatment site where the device is to be used. According to some examples, the method includes (at step 4202) supplying electricity to a first electrode. As described above, this electricity causes an arcing discharge across a spark gap that creates cavitation bubbles.

[0191] The method may include (in step 4204) arcing electricity from the first electrode to the second electrode at random locations around the circumference of the electron emitter. Because the arcing occurs randomly around the circumference, no single spot on the electron emitter electrode is subject to constant arcing, potentially reducing device degradation due to repeated arcing from a single point and increasing the device's life expectancy overall.

[0192] 43 is a flowchart illustrating an exemplary method of using a multi-emitter IVL catheter. In some examples, the method includes (at step 4300) providing a device. The device may be any of the devices described herein, as well as any other device that may be suitable for IVL.

[0193] According to some examples, the method may include (at step 4302) supplying electricity to a first electron emitter. The electron emitter may include first and second electrodes across which electricity can arc. The method may include (at step 4304) arcing electricity between the first and second electrodes. As described above, the electricity is used to generate an arc across a spark gap between the first and second electrodes, thus generating cavitation bubbles.

[0194] In some examples, the method includes (in step 4306) supplying electricity to a second electron emitter. The second electron emitter may be longitudinally separated from the first electron emitter. Additionally, the second electron emitter may be wired (by a power wire) independently from the first electron emitter. This independent wiring may allow for selective powering of the electron emitter and thus enable the electron emitter to arc and generate cavitation bubbles in a particular pattern or as desired by a user, as described below in FIG. 44. According to some examples, the method includes (in step 4308) arcing electricity between the third electrode and the fourth electrode. Similar to the first electrode and the second electrode, electricity is used to generate an arc across the spark gap between the third electrode and the fourth electrode, thus generating cavitation bubbles.

[0195] FIG. 44 is a flowchart illustrating an exemplary method for controlling individual emitters in an IVL catheter. The method may include manually selecting (in step 4400) the electron emitter to be powered. If multiple electron emitters are present, they may be powered by separate power wires, whereby the electron emitters are wired in parallel (as seen in FIGS. 15A, 15B, 16A, and 38A). This independent wiring also allows the electron emitters to be individually powered, meaning that the user can select which electron emitter should be fired rather than firing all of the emitters at once.

[0196] In some examples, the method includes determining (in step 4402) the treatment location closest to the electron emitter. In a length of treatment area affected by a calcified lesion, the operator may want to focus on a single spot for treatment. In some devices, the entire device is powered at once, so the entire length of the treatment area is treated, potentially including areas not requiring treatment. With a single emitter, treating an area may involve repositioning the IVL device after each firing so that the cavitation bubbles are focused in the correct location. By wiring the electron emitters in parallel, the operator may select the electron emitter closest to the treatment location and fire that emitter individually without having to move the device or fire other included emitters.

[0197] According to some examples, the method includes programming (at step 4404) a sequence of electron emitters to be powered. Instead of requiring manual selection of emitters by the operator, the device may include pre-programmed sequences. If the operator encounters a recognized pattern of calcified lesions, the operator can select a pre-programmed sequence to treat the recognized pattern. Additionally, if the operator wants to program a new pattern, i.e., a pattern that the operator sees frequently but has not yet been programmed, the operator may program a particular sequence of emitters to be fired for future use.

[0198] 45A-45D are perspective views of an exemplary emitter including various support posts. In each of FIGS. 45A, 45B, 45C, and 45D, the first electrode 4502 and the second electrode 4504 are separated from one another by support posts 4506. In each figure, the support posts 4506 are positioned and fabricated such that the support posts 4506 can be removed through mechanical means, such as via a laser or by manual manipulation of the support posts 4506 by an operator. The support posts 4506 can be configured such that the first electrode 4502 and the second electrode 4504 are separated by a consistent distance around their respective perimeters, thereby allowing any arcing that forms to occur randomly around these perimeters.

[0199] As shown in each of FIGS. 45A, 45B, 45C, and 45D, the posts 4506 connect to recesses 4508 in the first electrode 4502 and the second electrode 4504. These recesses 4508 may create localized mechanical weakness and facilitate manual removal of the posts 4506 by the manufacturer. In these examples, the areas of the recesses 4508 create small gaps around the peripheries of the first electrode 4502 and the second electrode 4504 when the posts 4506 are removed, thereby creating preferential locations around the peripheries for arcing to occur. Because these recesses 4508 are small, arcing locations still occur around most of these peripheries. Additionally, although not shown in these figures, the posts 4506 may be perforated in addition to or instead of the recesses 4508 to create this increased mechanical weakness.

[0200] 45A shows a "V-shaped" post 4506a. In this illustration, two small rectangular pieces extend at an angle from each of the first electrode 4502 and second electrode 4504, then meet in the middle to form an apex. A manufacturer can pull at or near this apex to remove the post 4506a.

[0201] In Figure 45B, the post 4506b extends directly across the gap between the first electrode 4502 and the second electrode 4504. A triangular shaped protrusion 4510a runs across the center of the post 4506b, which the manufacturer can pull to remove the post 4506b.

[0202] In Figure 45C, a post 4506c extends directly across the gap between the first electrode 4502 and the second electrode 4504. A rectangular protrusion 4510b runs across the center of the post 4506c, which the manufacturer can pull to remove the post 4506c.

[0203] As a final example, in Figure 45D, a post 4506d extends directly across the gap between the first electrode 4502 and the second electrode 4504. A trapezoidal shaped protrusion 4510c runs across the center of the post 4506d, which the manufacturer can pull to remove the post 4506d.

[0204] Figures 46 and 47 are side views of exemplary emitters, and Figure 48 is a side view of two pairs of these exemplary emitters. Specifically, Figure 46 shows an emitter 4600 including a first electrode 4602 having a first width 4606 and a second electrode 4604 having a second width 4608. A spark gap 4610 exists between the first electrode 4602 and the second electrode 4604. Additionally, both electrodes can be seen to at least partially surround an inner elongated structure 4612.

[0205] By making the first width 4606 narrower than the second width 4608, the resistance of each particular electrode can be better controlled. In this way, different voltages can generate different sized bubbles and therefore different magnitude pressure waves. Additionally, in systems with two or more emitters 4600, these different resistance electrodes can control the timing of the firing of the emitters 4600, thereby generating specific sequences or complex pressure waves.

[0206] FIG. 47 shows an emitter 4700 including a first electrode 4702 and a second electrode 4704. The first electrode 4702 and the second electrode 4704 can at least partially surround an inner elongated structure 4708. Also shown in FIG. 47 are protrusions 4706 on each of the first electrode 4702 and the second electrode 4704. These protrusions 4706 can enable preferential arcing from the first electrode 4702 to the second electrode 4704. It will be understood that the protrusions 4706 may be present only on the first electrode 4702 or only on the second electrode 4704 to create this preferential arcing. Additionally, these emitters 4700 may be rotatable so that an operator can orient the protrusions 4706 toward the area of ​​calcification being treated, thus potentially improving the effectiveness of the pressure wave therapy.

[0207] 48 shows two emitters, one having a first electrode 4802 and a second electrode 4804 separated by a first spark gap 4810, and a second emitter having a third electrode 4806 and a fourth electrode 4808 separated by a second spark gap 4812. Each of the first electrode 4802, second electrode 4804, third electrode 4806, and fourth electrode 4808 can at least partially surround an inner elongated structure 4814.

[0208] 48, the first spark gap 4810 can be wider than the second spark gap 4812. These different width spark gaps can allow for additional control over the pressure waves that are formed and can allow complex pressure wave profiles to be utilized.

[0209] Although FIG. 48 shows only two emitters, it should be understood that a greater number of emitters can be used in the device as long as it remains capable of traversing the patient's vasculature.

[0210] Figures 49, 50, 51, and 52 are side views of example emitters including three electrodes, and Figure 53 is a side view of a pair of these example emitters. Specifically, Figure 49 is a side view of an example three-electrode emitter 4900 including a first electrode 4902, a second electrode 4904, and a third electrode 4906, each of which at least partially surrounds an inner elongated structure 4918. The first electrode 4902 is shown separated from the second electrode 4904 by a first spark gap 4908, and the second electrode 4904 is shown separated from the third electrode 4906 by a second spark gap.

[0211] The first electrode 4902 has a first width 4912, the second electrode 4904 has a second width 4914, and the third electrode 4906 has a third width 4916. As can be seen in FIG. 49 , the second width 4914 is greater than the first width 4912 and the third width 4916. As shown in FIG. 49 , the first width 4912 and the third width 4916 can be equal or approximately equal. However, this is not strictly necessary, and as discussed above, increasing either of these widths can change the resistance through the electrode, thereby changing the spark generated.

[0212] In some examples, the second electrode 4904 is grounded, and the first electrode 4902 and the third electrode 4906 are powered in either series or parallel. In parallel, the first electrode 4902 and the third electrode 4906 can be individually selected for firing (i.e., arcing to the second electrode 4904). This configuration can allow a single ground electrode to receive arcing from either side, thus potentially doubling the spark production from this emitter 4900. Additionally, in some examples, the ability to selectively activate either side can also potentially double the average lifespan of the emitter 4900.

[0213] In another example, the second electrode 4904 is powered and the first electrode 4902 and the third electrode 4906 are again grounded, either in series or in parallel. In parallel, the first electrode 4902 and the third electrode 4906 can be individually selected to receive the arc discharge from the second electrode 4904. The advantages of such a configuration are similar to those described above.

[0214] Figure 50 is a side view of another exemplary three-electrode emitter 5000, which is similar in many respects to emitter 4900 of Figure 49. Emitter 5000 is shown to include a first electrode 5002, a second electrode 5004, and a third electrode 5006, each of which at least partially surrounds an inner elongated structure 5018. The first electrode 5002 is shown separated from the second electrode 5004 by a first spark gap 5008, and the second electrode 5004 is shown separated from the third electrode 5006 by a second spark gap 5010.

[0215] The first electrode 5002 has a first width 5012, the second electrode 5004 has a second width 5014, and the third electrode 5006 has a third width 5016. As shown in Figure 50, the second width 5014 is narrower than the first width 5012 and the third width 5016. The first width 5012 and the third width 5016 can be equal or approximately equal, although this is not strictly necessary.

[0216] In some examples, the second electrode 5004 is grounded and the first electrode 5002 and the third electrode 5006 are powered in either series or parallel. In other examples, the second electrode 5004 is powered and the first electrode 5002 and the third electrode 5006 are grounded in either series or parallel. The advantages of such configurations have been previously discussed and will not be repeated here.

[0217] FIG. 51 is a side view of an additional three-electrode emitter 5100 including a first electrode 5102, a second electrode 5104, and a third electrode 5106, each of which at least partially surrounds an inner elongated structure 5110. While the first electrode 5102, the second electrode 5104, and the third electrode 5106 are shown to be the same width, it is understood that this exemplary emitter 5100 may function in other configurations. As shown in FIG. 51 , the first electrode 5102 has a protrusion 5108 facing the second electrode 5104, and the second electrode 5104 has a protrusion 5108 facing the first electrode 5102. Similarly, the second electrode 5104 includes a protrusion 5108 facing the third electrode 5106, and the third electrode 5106 includes a protrusion 5108 facing the second electrode 5104.

[0218] These protrusions create a preferential spark gap location so that the spark gap is no longer allowed to occur randomly around the periphery of each electrode. Only one of these protrusions is required to cause this preferential location of the spark. For example, only the second electrode 5104 may include a protrusion 5108, while the first electrode 5102 and the third electrode 5106 do not. Conversely, perhaps the first electrode 5102 and the third electrode 5106 include a protrusion 5108, but the second electrode 5104 does not. In some examples, if desired, perhaps only the first electrode 5102 includes a protrusion, thus making the spark gap between the first electrode 5102 and the second electrode 5104 preferential to the location of the protrusion 5108, while the spark gap between the second electrode 5104 and the third electrode 5106 remains random around the periphery of these electrodes.

[0219] The advantages of wiring configurations will not be specifically repeated here, but in some examples, the second electrode 5104 is grounded and the first electrode 5102 and the third electrode 5106 are powered in either series or parallel, while in other examples, the second electrode 5104 is powered and the first electrode 5102 and the third electrode 5106 are grounded in either series or parallel.

[0220] 52 is a side view of another exemplary three-electrode emitter 5200 including a first electrode 5202, a second electrode 5204, and a third electrode 5206, each of which at least partially surrounds an inner elongated structure 5212. While the first electrode 5202, second electrode 5204, and third electrode 5206 are shown as being the same width, it is understood that this exemplary emitter 5200 can function with these examples of FIGS. 49 and 50. As shown, the first electrode 5202 is separated from the second electrode 5204 by a first spark gap 5208, and the second electrode 5204 is separated from the third electrode 5206 by a second spark gap 5210.

[0221] First spark gap 5208 is shown narrower than second spark gap 5210. The different lengths of these spark gaps can allow for control of the pressure waves that are generated. This can be useful when lower or higher power pressure waves are required for a particular application. These pressure waves can also be combined, either through simultaneous or individual firing of the electrodes, to create a composite pressure wave.

[0222] In some examples, the second electrode 5204 is grounded and the first electrode 5202 and the third electrode 5206 are powered in either series or parallel. In other examples, the second electrode 5204 is powered and the first electrode 5202 and the third electrode 5206 are grounded in either series or parallel.

[0223] 53 and 54 show side views of an exemplary pair of three-electrode emitters. Specifically, FIG. 53 shows a side view of a first emitter including a first electrode 5302, a second electrode 5304, and a third electrode 5306, and a second emitter including a fourth electrode 5308, a fifth electrode 5310, and a sixth electrode 5312. Each of the first electrode 5302, the second electrode 5304, the third electrode 5306, the fourth electrode 5308, the fifth electrode 5310, and the sixth electrode 5312 can at least partially surround an inner elongated structure 5322.

[0224] First electrode 5302 is shown separated from second electrode 5304 by first spark gap 5314, and second electrode 5304 is shown separated from third electrode 5306 by second spark gap 5316. Similarly, fourth electrode 5308 is shown separated from fifth electrode 5310 by third spark gap 5318, and fifth electrode 5310 is shown separated from sixth electrode 5312 by fourth spark gap 5320.

[0225] First spark gap 5314, second spark gap 5316, third spark gap 5318, and fourth spark gap 5320 are all shown as having the same width, however, this is not strictly necessary and various spark gap lengths can be implemented.

[0226] Additionally, an emitter including a first electrode 5302, a second electrode 5304, and a third electrode 5306 refers to an emitter including two wide outer electrodes and one narrow inner electrode, and an emitter including a fourth electrode 5308, a fifth electrode 5310, and a sixth electrode 5312 refers to an emitter including one wide inner electrode and two narrow outer electrodes. Indeed, any emitter as described throughout this disclosure can be used in conjunction with any other emitter in the same device, if desired.

[0227] The second electrode 5304, fourth electrode 5308, and sixth electrode 5312 all exhibit approximately the same width, and the first electrode 5302, third electrode 5306, and fifth electrode 5310 all exhibit approximately the same width, which is greater than the width of the second electrode 5304, fourth electrode 5308, and sixth electrode 5312. This is not strictly necessary, and in fact, all of the electrodes can have different widths from one another if desired.

[0228] 54 shows a side view of a first emitter including a first electrode 5402, a second electrode 5404, and a third electrode 5406, and a second emitter including a fourth electrode 5408, a fifth electrode 5410, and a sixth electrode 5412. Each of the first electrode 5402, the second electrode 5404, the third electrode 5406, the fourth electrode 5408, the fifth electrode 5410, and the sixth electrode 5412 can at least partially surround an inner extension structure 5422.

[0229] In this view, first electrode 5402, second electrode 5404, third electrode 5406, fourth electrode 5408, fifth electrode 5410, and sixth electrode 5412 all appear to have the same width. While this is not strictly necessary, this view illustrates the varying degrees of width of the spark gap between successive electrodes, and therefore, for simplicity, the electrodes are shown as the same size.

[0230] 54, first electrode 5402 is shown separated from second electrode 5404 by first spark gap 5414, and second electrode 5404 is shown separated from third electrode 5406 by second spark gap 5416. Similarly, fourth electrode 5408 is shown separated from fifth electrode 5410 by third spark gap 5418, and fifth electrode 5410 is shown separated from sixth electrode 5412 by fourth spark gap 5420.

[0231] First spark gap 5414 and second spark gap 5416 are shown as being approximately the same width, and third spark gap 5418 and fourth spark gap 5420 are shown as being the same width but narrower than first spark gap 5414 and second spark gap 5416. In this manner, an emitter including first electrode 5402, second electrode 5404, and third electrode 5406 can generate pressure waves of different power than an emitter including fourth electrode 5408, fifth electrode 5410, and sixth electrode 5412. Through either simultaneous, timed, or independently controlled firing of these electrodes, a composite pressure wave can be generated.

[0232] Additionally, while the spark gap of each emitter is shown to be the same size, it should be understood that further customization and control of the spark gap width for a particular compound pressure wave formation can be achieved by using the example emitters as described above.

[0233] In both Figures 53 and 54, several different wiring configurations can be constructed depending on the user's needs. For example, the second electrodes 5304 and / or 5404 and the fifth electrodes 5310 and / or 5410 can be wired to ground, in sequence, while the first electrodes 5302 and / or 5402, the third electrodes 5306 and / or 5406, the fourth electrodes 5308 and / or 5408, and the sixth electrodes 5312 and / or 5412 are wired to power, in sequence. In this scenario, the power and ground wires can also be reversed. In this example, when power is applied, all electrodes fire.

[0234] In a further example, the second electrodes 5304 and / or 5404 and the fifth electrodes 5310 and / or 5410 can receive their own independent wires and are therefore wired in parallel, in which case the emitters can fire independently of each other regardless of whether these wires return to ground or receive a voltage.

[0235] In yet another example, the first electrodes 5302 and / or 5402, the third electrodes 5306 and / or 5406, the fourth electrodes 5308 and / or 5408, and the sixth electrodes 5312 and / or 5412 can each receive their own independent wires and are thus wired in parallel. In this case, not only can the emitters be fired independently of one another, but each of the first electrodes 5302 and / or 5402, the third electrodes 5306 and / or 5406, the fourth electrodes 5308 and / or 5408, and the sixth electrodes 5312 and / or 5412 can be fired independently, thus providing even greater control over which spark gap is utilized. This is regardless of whether these wires return to ground or receive a voltage. In this example, the second electrodes 5304 and / or 5404 and the fifth electrodes 5310 and / or 5410 may also receive their own independent wires, but the addition of these wires does not affect the parallel nature of the circuit in any way.

[0236] Additionally, other wiring configurations can be used, such as wiring the second electrodes 5304 and / or 5404, the fourth electrodes 5308 and / or 5408, and the sixth electrodes 5312 and / or 5412 in series. The practical effect of such a configuration is to allow firing of individual electrodes of one emitter, while other emitters may fire both electrodes at once.

[0237] 53 and 54 show only two emitters, it should be understood that a greater number of emitters can be used in the device as long as it remains capable of traversing the patient's vasculature.

[0238] Figure 55 is a side view of an exemplary three-electrode spiral emitter 5500. As shown in Figure 55, a first electrode 5502, a second electrode 5504, and a third electrode 5506 are spirally spiraled around each other. The length of the emitter may be shorter or longer than that shown, depending on the needs of the user. Additionally, although not shown in Figure 55, the emitter 5500 may be disposed on an inner elongated structure (and may be adhered via a potting material, etc.) for delivery to a target site.

[0239] As can be seen in this figure, a first electrode 5502 is separated from a second electrode 5504 by a first spark gap 5508, and the second electrode 5504 is separated from a third electrode 5506 by a second spark gap 5510. Due to the spiral nature of each electrode, the first spark gap 5508 and the second spark gap 5510 are also spiral. As shown in FIG. 55, the first spark gap 5508 and the second spark gap 5510 are approximately equal throughout the length of the emitter 5500. This allows for random spark formation throughout the circumference and length of the emitter 5500, thus further extending the life expectancy of the emitter 5500 and the number of sparks that can form before the emitter 5500 needs to be shut down to avoid overheating.

[0240] While the second electrode 5504 is shown wider than the first electrode 5502 and the third electrode 5506, it will be understood that this is not strictly necessary. Additionally, the second electrode 5504 can receive power while the first electrode 5502 and the third electrode 5506 are returned to ground, or vice versa.

[0241] FIG. 56 is a side view of another three-electrode spiral emitter 5600. The emitter 5600 includes a first electrode 5602 separated from a second electrode 5604 by a first spark gap 5608, which in turn is separated from a third electrode 5606 by a second spark gap 5610. In this example, the second spark gap 5610 is wider than the first spark gap, allowing preferential sparking between the first electrode 5602 and the second electrode 5604. In some examples, when the first electrode 5602 and the third electrode 5606 are wired in parallel (either to ground or power), the second spark gap 5610 can be used to generate a spark of a different degree of energy than that of the first spark gap 5608. In this manner, compound pressure waves can also be created by sequential or simultaneous firing of the electrodes.

[0242] 57 is a side view of an additional three-electrode spiral emitter 5700. Emitter 5700 includes a first electrode 5702 separated from a second electrode 5704 by a first spark gap, which in turn is separated from a third electrode 5706 by a second spark gap. In this example, the spark gap decreases in width over the length of emitter 5700.

[0243] 57, proximal first spark gap 5708 (defined here as the spark gap closest to the proximal end of the emitter) and proximal second spark gap 5710 are wider than their distal counterparts, distal first spark gap 5712 and distal second spark gap 5714, respectively. In this example, when the proximal end of emitter 5700 is powered, the inherent resistance of the material from which emitter 5700 is made can be overcome. By reducing the width of the first and second spark gaps, electricity does not find a preferential location to jump from one electrode to another, thus maintaining the truly random nature of spark formation location.

[0244] 58 is a side view of an exemplary three-electrode spiral emitter 5800, as can be seen while it is being articulated. In this view, the emitter 5800 includes a first electrode 5802 separated from a second electrode 5804 by a first spark gap 5808, which in turn is separated from a third electrode 5806 by a second spark gap 5810. In this view, the emitter 5800 is articulated or bent "downward" (downward relative to the perspective view shown). This can be done through manipulation of the emitter 5800 itself or a structure, such as an internal elongated structure, to which the emitter 5800 is attached.

[0245] By articulating the emitter 5800, the first spark gap 5808 and the second spark gap 5810 narrow on the side of the emitter 5800 that is bent and widen on the side of the emitter 5800 opposite the bent side. In this way, even a slight bend in the emitter 5800 can create a preferential location for electricity to arc from one electrode to another, thereby allowing the operator to have some control over the direction of emission and pressure wave propagation.

[0246] 59 is a side view of a two-electrode spiral emitter 5900. The emitter 5900 includes a first electrode 5902 separated from a second electrode 5904 by a spark gap 5906. The use of only two electrodes, and therefore only one spark gap 5906, can reduce the ability to generate compound pressure waves, while also reducing the footprint of the emitter 5900, thus allowing for random spark formation and pressure wave propagation throughout the length of the emitter 5900 while still reducing material needs and potential size constraints.

[0247] A wider gap is shown between the second electrode 5904 and the first electrode 5902 on the opposite side of the spark gap 5906 to prevent spark formation from occurring on that side of the electrodes. Again, this is not strictly necessary, and in fact the gaps between the first electrode 5902 and the second electrode 5904 on either side of the first electrode 5902 can be the same width, thus allowing spark formation to occur within either of these gaps.

[0248] 60 is a side view of an exemplary two-electrode spiral emitter 6000 as it might appear while articulated. The emitter 6000 includes a first electrode 6002 separated from a second electrode 6004 by a spark gap 6006. The emitter 6000 can be articulated so that the spark gap 6006 is narrower on the side of the emitter 6000 that is bent toward it and wider on the side of the emitter 6000 opposite the bend. In this way, the side of the emitter 6000 that is bent toward it becomes the preferential side for spark generation while still allowing pressure waves to propagate randomly through the length of the emitter 6000.

[0249] Figure 61A is a side view of emitters with an exemplary wiring configuration, and Figure 61B is a side view of electrode pairs of two of these emitters. Specifically, Figure 61A illustrates a first emitter 6100a, a second emitter 6100b, a third emitter 6100c, and a fourth emitter 6100d, each of which can at least partially surround an inner extension structure 6106.

[0250] A wire 6102 is shown connected to each of the first emitter 6100a, second emitter 6100b, third emitter 6100c, and fourth emitter 6100d, thus indicating that these emitters 6100 are wired in series through this single wire 6102. This wire 6102 can either ground each of the emitters 6100 or provide power to each of the emitters 6100, depending on the needs of the user.

[0251] On the other side of the inner extension structure 6106, there may be a multi-filar wire 6104. This multi-filar wire 6104 may be a collection of individual wires helically wrapped around each other. In other examples, the multi-filar wire 6104 may be a ribbon wire. In still other examples, there may not be a multi-filar wire 6104 at all, and instead, individual wires may be adjacent to each other. In each emitter 6100, one of the wires of the multi-filar wire 6104 may be split from the rest of the wire and connected to the emitter 6100. Each of the wires of the multi-filar wire 6104 may either be grounded or provide power to each emitter 6100, opposite that of the wire 6102. This multi-filar wire 6104 configuration allows for parallel wiring of each of the emitters 6100, resulting in a smaller footprint within the device.

[0252] Although four emitters 6100 are illustrated in FIG. 61A, it should be understood that a greater number of emitters can be used in the device as long as it remains capable of traversing the patient's vasculature.

[0253] Figure 61B shows a side view, with hidden lines, of what may occur within each emitter 6100. For simplicity, a two-electrode emitter is shown in Figure 61B, but it is understood that other emitters, such as a three-electrode emitter, may also be implemented in this device. As shown, the first emitter 6100a includes a first electrode 6108 and a second electrode 6110, and the second emitter includes a third electrode 6112 and a fourth electrode 6114.

[0254] In FIG. 61B , the wires of the multi-filar wire 6104 can be seen separating from the multi-filar wire 6104, one for each emitter. A first wire of the multi-filar wire 6104 branches and connects to the second electrode 6110. A second wire of the multi-filar wire 6104 branches and connects to the fourth electrode 6114. On the other side, the wire 6102 is shown extending through each of the electrodes, it being understood that this wire 6102 connects the electrodes sequentially and only electrically connects with electrodes that are not powered (or in other examples not grounded) by the multi-filar wire 6104. Thus, the wire 6102 is electrically connected to the first electrode 6108 and the third electrode 6112 in this example.

[0255] The present disclosure includes a device including an elongate body. In some examples, the device includes a balloon positioned at a distal portion of the elongate body, whereby the balloon is configured to receive a fluid that inflates the balloon such that an outer surface of the balloon contacts an inner surface of a target treatment site within a patient's vasculature. According to some examples, the device includes an electron emitter positioned within the balloon along a central longitudinal axis of the elongate body, the electron emitter configured to propagate pressure waves radially outward through the fluid to fragment calcified lesions at the target treatment site. The electron emitter may include a first electrode and a second electrode. In some examples, the first electrode is longitudinally spaced from the second electrode such that a longitudinal spacing forms a spark gap between the first electrode and the second electrode. According to some examples, the first electrode and the second electrode at least partially surround the elongate body.

[0256] The first electrode and the second electrode may define a circle. In some examples, the first electrode defines a first perimeter facing the spark gap, the second electrode defines a second perimeter facing the spark gap, and the first perimeter faces the second perimeter. According to some examples, the electron emitter is configured to generate sparks at random positions around the first perimeter, thereby generating an arc discharge at the second perimeter.

[0257] The first electrode may define a first perimeter facing the spark gap, and the second electrode may define a second perimeter facing the spark gap, the first perimeter facing the second perimeter. In some examples, the first perimeter is parallel to the second perimeter. According to some examples, the device further includes a power wire electrically coupled to the first electrode. The device may further include a ground wire electrically coupled to the second electrode.

[0258] In some examples, the electron emitter including the first electrode and the second electrode is a first electron emitter, and the spark gap is a first spark gap. According to some examples, the second electron emitter includes a third electrode and a fourth electrode. The second electron emitter may be longitudinally spaced apart from the first electron emitter. In some examples, the third electrode is longitudinally spaced apart from the fourth electrode such that the longitudinal spacing forms a second spark gap between the third electrode and the fourth electrode. According to some examples, the third electrode and the fourth electrode at least partially surround the elongated body.

[0259] The first electrode, the second electrode, the third electrode, and the fourth electrode may define a circle. In some examples, the first electrode defines a first outer perimeter facing the first spark gap, the second electrode defines a second outer perimeter facing the first spark gap, and the first outer perimeter faces the second outer perimeter. According to some examples, the third electrode defines a third outer perimeter facing the second spark gap, and the fourth electrode defines a fourth outer perimeter facing the second spark gap, and the third outer perimeter faces the fourth outer perimeter. The first outer perimeter may be parallel to the second outer perimeter. In some examples, the third outer perimeter is parallel to the fourth outer perimeter.

[0260] According to some examples, the device further includes a first power wire electrically coupled to the first electrode. The device may further include a second power wire electrically coupled to the third electrode. In some examples, the device further includes a ground wire electrically coupled to the second electrode and the fourth electrode. According to some examples, when the first electrode receives electricity, the electricity can arc to the second electrode. When the third electrode receives electricity, the electricity can arc to the fourth electrode.

[0261] In some examples, the first power wire is configured to provide electricity separately from the second power wire. According to some examples, the first electron emitter is configured to propagate pressure waves independently from the second electron emitter.

[0262] The present disclosure also includes a device including an elongated body. The device may include a first electron emitter positioned along a central longitudinal axis of the elongated body. In some examples, the device includes a second electron emitter positioned along the central longitudinal axis of the elongated body, the second electron emitter being longitudinally spaced from the first electron emitter. According to some examples, the device includes a first power wire electrically coupled to the first electron emitter. The device may include a second power wire electrically coupled to the second electron emitter. In some examples, the first electron emitter and the second electron emitter at least partially surround the elongated body. According to some examples, the first power wire is configured to provide electricity separately from the second power wire.

[0263] The device may further include a balloon positioned at a distal portion of the elongate body, the balloon configured to receive a fluid for inflation such that an outer surface of the balloon contacts an inner surface of a target treatment site within the patient's vasculature. In some examples, the first electron emitter and the second electron emitter are located within the balloon. According to some examples, the first electron emitter and the second electron emitter are configured to propagate pressure waves radially outward through the fluid to fragment calcified lesions at the target treatment site.

[0264] The device may further include a ground wire electrically coupled to the first electron emitter and the second electron emitter. In some examples, the first electron emitter includes a first electrode and a second electrode, and the first power wire is electrically coupled to the first electrode, such that when the first electrode receives electricity, the electricity generates an arc discharge to the second electrode. According to some examples, the second electron emitter includes a third electrode and a fourth electrode, and the second power wire is electrically coupled to the third electrode, such that when the third electrode receives electricity, the electricity generates an arc discharge to the fourth electrode. The first electron emitter may be configured to propagate pressure waves independently of the second electron emitter.

[0265] The present disclosure also includes a device including an elongate body. In some examples, the device includes a balloon positioned at a distal portion of the elongate body, the balloon configured to receive a fluid for inflation such that an outer surface of the balloon contacts an inner surface of a target treatment site within a patient's vasculature. According to some examples, the device includes a first electron emitter positioned along a central longitudinal axis of the elongate body within the balloon. The first electron emitter may include a first electrode and a second electrode. In some examples, the first electrode is longitudinally spaced from the second electrode such that a longitudinal spacing forms a spark gap between the first and second electrodes. According to some examples, the device includes a second electron emitter positioned along the central longitudinal axis of the elongate body within the balloon, the second electron emitter being longitudinally spaced from the first electron emitter. The second electron emitter may include a third electrode and a fourth electrode. In some examples, the third electrode is longitudinally spaced from the fourth electrode such that the longitudinal spacing forms a spark gap between the third electrode and the fourth electrode. According to some examples, the first electrode, the second electrode, the third electrode, and the fourth electrode at least partially surround the elongated body. The first electron emitter and the second electron emitter may be configured to propagate pressure waves radially outward through the fluid to fragment calcified lesions at the target treatment site.

[0266] In some examples, the first electrode defines a first outer periphery facing the first spark gap, the second electrode defines a second outer periphery facing the first spark gap, and the first outer periphery faces the second outer periphery. According to some examples, the third electrode defines a third outer periphery facing the second spark gap, and the fourth electrode defines a fourth outer periphery facing the second spark gap, and the third outer periphery faces the fourth outer periphery. The first outer periphery may be parallel to the second outer periphery. In some examples, the third outer periphery is parallel to the fourth outer periphery. According to some examples, the first outer periphery is parallel to the third outer periphery.

[0267] The device may further include a first power wire electrically coupled to the first electrode. In some examples, the device further includes a second power wire electrically coupled to the third electrode. According to some examples, the device further includes a ground wire electrically coupled to the second electrode and the fourth electrode. When the first electrode receives electricity, the electricity can generate an arc discharge at the second electrode. In some examples, when the third electrode receives electricity, the electricity generates an arc discharge at the fourth electrode. According to some examples, the first power wire is configured to provide electricity separately from the second power wire.

[0268] Also included in the present disclosure is a method including laser cutting an elliptical hypotube to define a first electrode and a second electrode positioned to define a longitudinal spark gap therebetween. In some examples, the method includes inserting an elongated body through the laser-cut elliptical hypotube. According to some examples, the method includes flowing a potting material around the laser-cut elliptical hypotube. The method may also include removing a legacy support structure from the laser-cut elliptical hypotube. In some examples, the method includes positioning the first electrode and the second electrode to define a longitudinal spark gap therebetween. In an alternative example, the step of inserting the elongated body occurs through the first electrode and the second electrode after the legacy support structure has been removed.

[0269] In some examples, laser cutting the oval hypotube includes laser cutting a parallelogram from a central portion of the oval hypotube such that the first electrode and the second electrode are separated by a support post. In additional or alternative examples, the cut shape is other than a parallelogram, such as a chevron pattern. According to some examples, removing the old support structure from the oval hypotube includes removing the support posts. Removing the support posts may be performed by laser cutting the support posts from the hypotube. In additional or alternative examples, removing the support posts may be performed by using a cutting tool, a mechanical tab break design, or a wheel-type cutting tool. In some examples, the first electrode defines a first perimeter. According to some examples, the second electrode defines a second perimeter. Removing the support posts may include separating the first electrode from the second electrode by a distance around and between the first and second perimeters.

[0270] In some examples, in response to removing the support posts, the first electrode and the second electrode are separated by a predetermined distance. According to some examples, the first electrode and the second electrode are separated by a predetermined distance around the first and second perimeters. In some examples, in response to removing the support posts, the first and second perimeters are parallel.

[0271] According to some examples, laser cutting the elliptical hypotube includes laser cutting three parallelograms from a central portion of the elliptical hypotube such that the first electrode and the second electrode are separated by three support posts. Removing the old support structure from the elliptical hypotube may include removing the three support posts. In some examples, the first electrode defines a first perimeter. According to some examples, the second electrode defines a second perimeter. Removing the three support posts may include separating the first electrode from the second electrode by a distance around and between the first perimeter and the second perimeter.

[0272] In some examples, inserting the elongated body through the laser cut oval hypotube includes at least partially surrounding the elongated body with the laser cut oval hypotube. According to some examples, flowing potting material around the laser cut oval hypotube includes securing the laser cut oval hypotube to the elongated body via an adhesive.

[0273] The method may further include welding a power wire to the first electrode. In some examples, welding the power wire to the first electrode occurs prior to inserting the elongated body through the laser-cut oval hypotube. According to some examples, the method may further include extending the power wire along the elongated body from the first electrode to the hub. Stated another way, the method may further include disposing the power wire along the elongated body from the first electrode to the hub.

[0274] In some examples, the method further includes welding a ground wire to the second electrode. According to some examples, welding the ground wire to the second electrode occurs before inserting the elongated body through the laser-cut oval hypotube. The method may further include extending the ground wire along the elongated body from the second electrode to the hub. Stated differently, the method may further include disposing the ground wire along the elongated body from the second electrode to the hub.

[0275] In some examples, the laser cut elliptical hypotube is a first laser cut elliptical hypotube, and the elliptical spark gap is a first elliptical spark gap. According to some examples, the method further includes laser cutting a second hypotube to define a third electrode and a fourth electrode and a second elliptical spark gap therebetween. The method may further include inserting an elongated body through the second laser cut elliptical hypotube. In some examples, the method further includes flowing a potting material around the second laser cut elliptical hypotube. According to some examples, the method further includes removing an old support structure from the second laser cut elliptical hypotube.

[0276] The method may further include welding a first power wire to the first electrode. In some examples, the method may further include welding a second power wire to the third electrode. According to some examples, the method may further include welding a ground wire to the second electrode. The method may further include welding a ground wire to the fourth electrode.

[0277] In some examples, welding the first power wire to the first electrode, welding the second power wire to the third electrode, welding the ground wire to the second electrode, and welding the ground wire to the fourth electrode occurs before inserting the elongated body through the first laser-cut oval hypotube and the second laser-cut oval hypotube.

[0278] The method may further include extending a first power wire along the elongated body from the first electrode to the hub. In some examples, the method may further include extending a second power wire along the elongated body from the third electrode to the hub. According to some examples, the method may further include extending a ground wire along the elongated body from the fourth electrode to the second electrode. The method may further include extending a ground wire along the elongated body from the second electrode to the hub.

[0279] Stated alternatively in relation to the previous paragraph, the method may further include disposing a first power wire along the elongated body from the first electrode to the hub. In some examples, the method may further include disposing a second power wire along the elongated body from the third electrode to the hub. According to some examples, the method may further include disposing a ground wire along the elongated body from the fourth electrode to the second electrode. The method may further include disposing a ground wire along the elongated body from the second electrode to the hub.

[0280] The present disclosure also includes a method including inserting a device into a patient's vasculature. The device may include an elongated body. In some examples, the device includes one or more electron emitters positioned along a central longitudinal axis of the elongated body. According to some examples, at least one of the one or more electron emitters includes a first electrode and a second electrode. The first electrode may be longitudinally spaced from the second electrode such that a longitudinal spacing defines a spark gap between the first electrode and the second electrode. In some examples, the first electrode and the second electrode at least partially surround the elongated body. According to some examples, the method includes supplying electricity to the first electrode. The method may include arcing electricity from the first electrode to the second electrode at random locations around the circumference of the electron emitter (i.e., around the circumferences of the first electrode and the second electrode).

[0281] The present disclosure also includes a method that includes providing an apparatus. The apparatus may include an elongated body. In some examples, the apparatus includes a first electron emitter positioned along a central longitudinal axis of the elongated body. According to some examples, the first electron emitter includes a first electrode and a second electrode arranged to define a first spark gap. The apparatus may include a second electron emitter positioned along the central longitudinal axis of the elongated body and longitudinally spaced from the first electron emitter. In some examples, the second electron emitter includes a third electrode and a fourth electrode arranged to define a second spark gap. According to some examples, the apparatus includes a first power wire configured to supply electricity to the first electrode. The apparatus may include a second power wire configured to supply electricity to the third electrode. In some examples, the apparatus includes a ground wire configured to ground the second electrode and the fourth electrode. According to some examples, the method includes supplying electricity to the first electron emitter. The method may include arcing electricity between a first electrode and a second electrode. In some examples, the method includes supplying electricity to a second electron emitter. According to some examples, the method includes arcing electricity between a third electrode and a fourth electrode.

[0282] Powering the first electron emitter and powering the second electron emitter may include manually selecting, via a user, the electron emitter to be powered. In some examples, manually selecting the electron emitter to be powered includes determining a treatment location closest to the electron emitter. According to some examples, powering the first electron emitter and powering the second electron emitter includes programming a sequence of the electron emitters to be powered.

[0283] Also included in the present disclosure is a system including an inner elongated structure defining a guidewire lumen. In some examples, the system includes a balloon positioned at a distal portion of the elongated body, the elongated body including the inner elongated structure, and the balloon configured to be inflated. According to some examples, the system includes an emitter 3500 positioned within the balloon along the elongated body, the emitter 3500 configured to emit pressure waves to fragment deposits within the organ. The emitter 3500 can include a first electrode and a second electrode arranged to form a spark gap between the first electrode and the second electrode.

[0284] In some examples, the inner extension structure includes a layer of polyimide 3510. According to some examples, the inner extension structure further includes a polymer layer 3504b. The polymer layer 3504b can at least partially surround the polyimide layer 3510. In some examples, the polymer layer 3504b includes a single polymer. According to some examples, the polymer layer 3504b includes a copolymer. The polyimide layer 3510 can include a doped polyimide. In some examples, the doped polyimide is non-metallic.

[0285] According to some examples, the system further includes a layer of reinforcement material 3508. The layer of polymer 3504b can at least partially surround the layer of reinforcement material 3508. In some examples, the layer of reinforcement material 3508 at least partially surrounds the layer of polyimide 3510.

[0286] According to some examples, the layer of reinforcement 3508 includes a braid. The layer of reinforcement 3508 can include a non-metallic material. In some examples, the non-metallic material is polyetheretherketone (PEEK). According to some examples, the layer of reinforcement 3508 includes Kevlar fibers.

[0287] The layer of reinforcement 3508 can include high density polyethylene fibers. In some examples, the high density polyethylene fibers are metallic. In some examples, the high density polyethylene fibers are non-metallic. The layer of reinforcement 3508 can be electrically conductive.

[0288] In some examples, the layer of reinforcement 3508 includes a multi-filar wire 6104 helically wrapped around the layer of polymer 3504b. According to some examples, the multi-filar wire 6104 includes a power wire for supplying power to the first electrode or the second electrode. The system can further include a layer of adhesive 3502 at least partially surrounding the layer of reinforcement 3508. In some examples, material is removed from the layer of adhesive 3502 to allow the multi-filar wire 6104 to be electrically coupled to the first electrode or the second electrode.

[0289] Also included in the present disclosure is a system including an inner elongated structure defining a guidewire lumen. In some examples, the system includes a balloon positioned at a distal portion of the elongated body, the elongated body including the inner elongated structure, and the balloon configured to be inflated. According to some examples, the system includes an emitter positioned along the elongated body and within the balloon, the emitter configured to emit pressure waves to fragment deposits within the organ. The emitter can include a first electrode 4502 and a second electrode 4504. In some examples, the first electrode 4502 is spaced from the second electrode 4504 such that a spacing forms a spark gap between the first electrode 4502 and the second electrode 4504.

[0290] According to some examples, the emitter further includes a post 4506 mechanically coupled to each of the first electrode 4502 and the second electrode 4504. The post 4506 can include less material than each of the first electrode 4502 and the second electrode 4504. In some examples, the location of coupling between the post 4506 and the first electrode 4502 includes a recess 4508 in the first electrode 4502. According to some examples, the location of coupling between the post 4506 and the second electrode 4504 includes a recess 4508 in the second electrode 4504. The posts 4506b, 4506c, and / or 4506d can traverse each of the first electrode 4502 and the second electrode 4504.

[0291] In some examples, posts 4506b, 4506c, and / or 4506d include protrusions 4510. According to some examples, protrusions 4510 are transverse to posts 4506b, 4506c, and / or 4506d. Protrusions 4510a can be triangular. In some examples, protrusions 4510b are rectangular. According to some examples, protrusions 4510c are trapezoidal.

[0292] The struts 4506a can extend at a non-perpendicular angle from each of the first electrode 4502 and the second electrode 4504. In some examples, the struts 4506 are configured to be removed. According to some examples, the struts 4506 are configured to keep the entire periphery of the first electrode 4502 a fixed distance away from the entire periphery of the second electrode 4504.

[0293] Also included in the present disclosure is a system including an inner elongated structure 4612, 4708, and / or 4814 including a guidewire lumen. In some examples, the system includes an outer elongated structure defining an inflation lumen. According to some examples, the system includes a balloon positioned at a distal portion of the elongated body, the elongated body including an inner elongated structure and an outer elongated structure, the balloon configured to receive fluid via the inflation lumen to be inflated. The system can include an emitter 4600 and / or 4700 positioned within the balloon along the elongated body, the emitter 4600 and / or 4700 configured to emit pressure waves to fragment deposits within the organ. In some examples, the emitter 4600 and / or 4700 includes a first electrode 4602, 4702, and / or 4802 and a second electrode 4604, 4704, and / or 4804. According to some examples, the first electrodes 4602, 4702, and / or 4802 are spaced apart from the second electrodes 4604, 4704, and / or 4804 to form a spark gap 4610 between the first electrodes 4602, 4702, and / or 4802 and the second electrodes 4604, 4704, and / or 4804. The first electrodes 4602, 4702, and / or 4802 and the second electrodes 4604, 4704, and / or 4804 can at least partially surround the inner elongated structure 4612, 4708, and / or 4814, respectively.

[0294] In some examples, the system further includes a power conductor electrically coupled to the first electrode 4602, 4702, and / or 4802. According to some examples, the system further includes a ground conductor electrically coupled to the second electrode 4604, 4704, and / or 4804. The second electrodes 4604, 4704, and / or 4804 can be narrower than the first electrodes 4602, 4702, and / or 4802. In some examples, the first electrodes 4602, 4702, and / or 4802 are narrower than the second electrodes 4604, 4704, and / or 4804.

[0295] According to some examples, the system further includes a protrusion 4706 on a side of the second electrode 4604, 4704, and / or 4804, the protrusion facing the first electrode 4602, 4702, and / or 4802. The emitters 4600 and / or 4700 may be rotatable. In some examples, the system further includes a protrusion 4706 on a side of the first electrode 4602, 4702, and / or 4802, the protrusion facing the second electrode 4604, 4704, and / or 4804. According to some examples, the emitters 4600 and / or 4700 are rotatable.

[0296] Emitter 4600 and / or 4700 may be first emitter 4600 and / or 4700, spark gap 4610 may be first spark gap 4810, and the system further includes second emitter 4600 and / or 4700 having a third electrode 4806 and a fourth electrode 4808. In some examples, third electrode 4806 is spaced apart from fourth electrode 4808 to form a second spark gap 4812 between third electrode 4806 and fourth electrode 4808. According to some examples, third electrode 4806 and fourth electrode 4808 at least partially surround inner elongated structure 4612, 4708, and / or 4814, respectively. First spark gap 4810 may be wider than second spark gap 4812.

[0297] In some examples, the power conductor is a first power conductor, and the system further includes a second power conductor electrically coupled to the third electrode 4806, and the ground conductor is electrically coupled to the fourth electrode 4808. According to some examples, the fourth electrode 4808 is narrower than the third electrode 4806. The third electrode 4806 can be narrower than the fourth electrode 4808.

[0298] In some examples, the system further includes a protrusion 4706 on a side of the fourth electrode 4808, the protrusion facing the third electrode 4806. According to some examples, the second emitter 4600 and / or 4700 is rotatable. The system further includes a protrusion 4706 on a side of the third electrode 4806, the protrusion facing the fourth electrode 4808. In some examples, the second emitter 4600 and / or 4700 is rotatable.

[0299] According to some examples, the first emitter 4600 and / or 4700 and the second emitter 4600 and / or 4700 are configured to propagate pressure waves independently of one another. The first emitter 4600 and / or 4700 and the second emitter 4600 and / or 4700 can be configured to generate a composite pressure wave from sequential firing of the first emitter 4600 and / or 4700 and the second emitter 4600 and / or 4700. In some examples, the first emitter 4600 and / or 4700 and the second emitter 4600 and / or 4700 are configured to generate a composite pressure wave from timed firing of the first emitter 4600 and / or 4700 and the second emitter 4600 and / or 4700.

[0300] According to some examples, the ground conductor is a first ground conductor, and the system further includes a second ground conductor electrically coupled to the fourth electrode 4808, and the power conductor is electrically coupled to the third electrode 4806. The fourth electrode 4808 can be narrower than the third electrode 4806. In some examples, the third electrode 4806 is narrower than the fourth electrode 4808.

[0301] According to some examples, the system further includes a protrusion 4706 on a side of the fourth electrode 4808, the protrusion facing the third electrode 4806. The second emitter 4600 and / or 4700 may be rotatable. In some examples, the system further includes a protrusion 4706 on a side of the third electrode 4806, the protrusion facing the fourth electrode 4808. According to some examples, the emitter 4600 and / or 4700 is rotatable.

[0302] The first emitter 4600 and / or 4700 and the second emitter 4600 and / or 4700 can be configured to propagate pressure waves independently of one another. In some examples, the first emitter 4600 and / or 4700 and the second emitter 4600 and / or 4700 are configured to generate a composite pressure wave from sequential firing of the first emitter 4600 and / or 4700 and the second emitter 4600 and / or 4700. According to some examples, the first emitter 4600 and / or 4700 and the second emitter 4600 and / or 4700 are configured to generate a composite pressure wave from timed firing of the first emitter 4600 and / or 4700 and the second emitter 4600 and / or 4700.

[0303] Also included in the present disclosure is a system including an inner elongate structure 4918, 5018, 5110, 5212, 5322, and / or 5422 defining a guidewire lumen. In some examples, the system includes an outer elongate structure including an inflation lumen. According to some examples, the system includes a balloon positioned at a distal portion of the elongate body, the elongate body including an inner elongate structure and an outer elongate structure, the balloon configured to receive fluid via the inflation lumen to be inflated. The system can include an emitter 4900, 5000, 5100, and / or 5200 positioned within the balloon along the elongate body, the emitter configured to emit pressure waves to fragment deposits within the organ. In some examples, the emitter includes a first electrode 4902, 5002, 5102, 5202, 5302, and / or 5402, a second electrode 4904, 5004, 5104, 5204, 5304, and / or 5404, and a third electrode 4906, 5006, 5106, 5206, 5306, and / or 5406. According to some examples, the first electrode 4902, 5002, 5102, 5202, 5302, and / or 5402 is spaced apart from the second electrode 4904, 5004, 5104, 5204, 5304, and / or 5404 to form a first spark gap 4908, 5008, 5208, 5314, and / or 5414 between the first electrode 4902, 5002, 5102, 5202, 5302, and / or 5402 and the second electrode 4904, 5004, 5104, 5204, 5304, and / or 5404. The second electrodes 4904, 5004, 5104, 5204, 5304, and / or 5404 can be spaced apart from the third electrodes 4906, 5006, 5106, 5206, 5306, and / or 5406, forming second spark gaps 4910, 5010, 5210, 5316, and / or 5416 between the second electrodes 4904, 5004, 5104, 5204, 5304, and / or 5404 and the third electrodes 4906, 5006, 5106, 5206, 5306, and / or 5406.In some examples, the first electrodes 4902, 5002, 5102, 5202, 5302, and / or 5402, the second electrodes 4904, 5004, 5105, 5204, 5204, and / or 5404, and the third electrodes 4906, 5006, 5106, 5206, 5306, and / or 5406 at least partially surround the inner extension structure 4918, 5018, 5110, 5212, 5322, and / or 5422, respectively.

[0304] According to some examples, the system further includes a power conductor electrically coupled to the second electrode 4904, 5004, 5104, 5204, 5304, and / or 5404. The system may include a first ground conductor electrically coupled to the first electrode 4902, 5002, 5102, 5202, 5302, and / or 5402. In some examples, the system includes a second ground conductor electrically coupled to the third electrode 4906, 5006, 5106, 5206, 5306, and / or 5406.

[0305] According to some examples, the second electrode 4904 is wider than the first electrode 4902 and the third electrode 4906. The width of the first electrode 4902 and the width of the third electrode 4906 may be the same. In some examples, the second electrode 5004 is narrower than the first electrode 5002 and the third electrode 5006. According to some examples, the width of the first electrode 5002 and the width of the third electrode 5006 are the same.

[0306] The system can further include a protrusion 5108 on a side of the second electrode 5104, the protrusion facing the first electrode 5102. In some examples, the emitter 5100 is rotatable. According to some examples, the system further includes a protrusion 5108 on a side of the first electrode 5102, the protrusion facing the second electrode 5104. The emitter 5100 can be rotatable. In some examples, the system further includes a protrusion 5108 on a side of the second electrode 5104, the protrusion facing the third electrode 5106. According to some examples, the emitter 5100 is rotatable. The system can include a protrusion 5108 on a side of the third electrode 5106, the protrusion facing the second electrode 5104. In some examples, the emitter 5100 is rotatable. According to some examples, the second spark gap 5210 is wider than the first spark gap 5208.

[0307] Emitter 4900, 5000, 5100, and / or 5200 may be a first emitter, and the system may further include a second emitter including a fourth electrode 5308 and / or 5408, a fifth electrode 5310 and / or 5410, and a sixth electrode 5312 and / or 5412. In some examples, the fourth electrode 5308 and / or 5408 is spaced apart from the fifth electrode 5310 and / or 5410 to form a third spark gap 5318 and / or 5418 between the fourth electrode 5308 and / or 5408 and the fifth electrode 5310 and / or 5410. According to some examples, fifth electrode 5310 and / or 5410 is spaced apart from sixth electrode 5312 and / or 5412 to form a fourth spark gap 5320 and / or 5420 between fifth electrode 5310 and / or 5410 and sixth electrode 5312 and / or 5412.

[0308] The system may further include a third ground conductor electrically coupled to the fourth electrode 5308 and / or 5408. In some examples, the system further includes a fourth ground conductor electrically coupled to the sixth electrode 5312 and / or 5412. According to some examples, a power conductor is electrically coupled to the fifth electrode 5310 and / or 5410.

[0309] The fifth electrode 5310 can be wider than the fourth electrode 5308 and the sixth electrode 5312. In some examples, the width of the fifth electrode 5310 is the same as the width of the second electrode. According to some examples, the width of the fourth electrode 5308 is the same as the width of the sixth electrode 5312. The width of the first electrode, the width of the third electrode, the width of the fourth electrode 5308, and the width of the sixth electrode 5312 can be the same.

[0310] In some examples, the fifth electrode is narrower than the fourth electrode and the sixth electrode. In some examples, the width of the fifth electrode is the same as the width of the second electrode. The width of the fourth electrode is the same as the width of the sixth electrode. In some examples, the width of the first electrode, the width of the third electrode, the width of the fourth electrode, and the width of the sixth electrode are the same.

[0311] According to some examples, the system further includes a protrusion on a side of the fifth electrode 5310 and / or 5410, the protrusion facing the fourth electrode 5308 and / or 5408. The second emitter may be rotatable. In some examples, the system further includes a protrusion on a side of the fourth electrode 5308 and / or 5408, the protrusion facing the fifth electrode 5310 and / or 5410. According to some examples, the second emitter is rotatable. The system further includes a protrusion on a side of the fifth electrode 5310 and / or 5410, the protrusion facing the sixth electrode 5312 and / or 5412. In some examples, the second emitter is rotatable. According to some examples, the system further includes a protrusion on a side of the sixth electrode 5312 and / or 5412, the protrusion facing the fifth electrode 5310 and / or 5410. The second emitter may be rotatable.

[0312] In some examples, the first emitter and the second emitter are configured to propagate pressure waves independently of each other. According to some examples, the first emitter and the second emitter are configured to generate a composite pressure wave from sequential firing of the first emitter and the second emitter. The first emitter and the second emitter can be configured to generate a composite pressure wave from timed firing of the first emitter and the second emitter.

[0313] In some examples, the third spark gap is wider than the fourth spark gap. In some examples, the width of the first spark gap and the width of the third spark gap are the same. In some examples, the width of the second spark gap and the width of the fourth spark gap are the same.

[0314] In some examples, the power conductor is a first power conductor, and the system further includes a second power conductor electrically coupled to the fifth electrode 5310 and / or 5410. According to some examples, the system further includes a third ground conductor electrically coupled to the fourth electrode 5308 and / or 5408. The system can further include a fourth ground conductor electrically coupled to the sixth electrode 5312 and / or 5412.

[0315] In some examples, the fifth electrode 5310 is wider than the fourth electrode 5308 and the sixth electrode 5312. According to some examples, the width of the fifth electrode 5310 and the width of the second electrode are the same. The width of the fourth electrode 5308 and the width of the sixth electrode 5312 may be the same. In some examples, the width of the first electrode, the width of the third electrode, the width of the fourth electrode 5308, and the width of the sixth electrode 5312 are the same.

[0316] According to some examples, the fifth electrode is narrower than the fourth electrode and the sixth electrode. The width of the fifth electrode and the width of the second electrode may be the same. In some examples, the width of the fourth electrode and the width of the sixth electrode are the same. According to some examples, the width of the first electrode, the width of the third electrode, the width of the fourth electrode, and the width of the sixth electrode are the same.

[0317] The system can further include a protrusion on a side of the fifth electrode 5310 and / or 5410, the protrusion facing the fourth electrode 5308 and / or 5408. In some examples, the second emitter is rotatable. According to some examples, the system can further include a protrusion on a side of the fourth electrode 5308 and / or 5408, the protrusion facing the fifth electrode 5310 and / or 5410. The second emitter can be rotatable. In some examples, the system can further include a protrusion on a side of the fifth electrode 5310 and / or 5410, the protrusion facing the sixth electrode 5312 and / or 5412. According to some examples, the second emitter is rotatable. The system can further include a protrusion on a side of the sixth electrode 5312 and / or 5412, the protrusion facing the fifth electrode 5310 and / or 5410. In some examples, the second emitter is rotatable.

[0318] According to some examples, the first emitter and the second emitter are configured to propagate pressure waves independently of each other. The first emitter and the second emitter can be configured to generate a composite pressure wave from sequential firing of the first emitter and the second emitter. In some examples, the first emitter and the second emitter are configured to generate a composite pressure wave from timed firing of the first emitter and the second emitter.

[0319] According to some examples, the third spark gap is wider than the fourth spark gap. The width of the first spark gap and the width of the third spark gap may be the same. In some examples, the width of the second spark gap and the width of the fourth spark gap are the same.

[0320] According to some examples, the system further includes a ground conductor electrically coupled to the second electrode 4904, 5004, 5104, 5204, 5304, and / or 5404. The system may further include a first power conductor electrically coupled to the first electrode 4902, 5002, 5102, 5202, 5302, and / or 5402. In some examples, the system further includes a second power conductor electrically coupled to the third electrode 4906, 5006, 5106, 5206, 5306, and / or 5406.

[0321] According to some examples, the second electrode 4904 is wider than the first electrode 4902 and the third electrode 4906. The width of the first electrode 4902 and the width of the third electrode 4906 may be the same. In some examples, the second electrode 5004 is narrower than the first electrode 5002 and the third electrode 5006. According to some examples, the width of the first electrode 5002 and the width of the third electrode 5006 are the same.

[0322] The system can further include a protrusion 5108 on a side of the second electrode 5104, the protrusion facing the first electrode 5102. In some examples, the emitter 5100 is rotatable. According to some examples, the system further includes a protrusion 5108 on a side of the first electrode 5102, the protrusion facing the second electrode 5104. The emitter can be rotatable. In some examples, the system further includes a protrusion 5108 on a side of the second electrode 5104, the protrusion facing the third electrode 5106. According to some examples, the emitter 5100 is rotatable. The system can further include a protrusion 5108 on a side of the third electrode 5106, the protrusion facing the second electrode 5104. In some examples, the emitter 5100 is rotatable. According to some examples, the second spark gap 5210 is wider than the first spark gap 5208.

[0323] Emitter 4900, 5000, 5100, and / or 5200 may be a first emitter, and the system may further include a second emitter including a fourth electrode 5308 and / or 5408, a fifth electrode 5310 and / or 5410, and a sixth electrode 5312 and / or 5412. In some examples, the fourth electrode 5308 and / or 5408 is spaced apart from the fifth electrode 5310 and / or 5410 such that a spacing forms a third spark gap 5318 and / or 5418 between the fourth electrode 5308 and / or 5408 and the fifth electrode 5310 and / or 5410. According to some examples, fifth electrode 5310 and / or 5410 is spaced apart from sixth electrode 5312 and / or 5412 to form a fourth spark gap 5320 and / or 5420 between fifth electrode 5310 and / or 5410 and sixth electrode 5312 and / or 5412.

[0324] The system may further include a third power conductor electrically coupled to the fourth electrode 5308 and / or 5408. In some examples, the system further includes a fourth power conductor electrically coupled to the sixth electrode 5312 and / or 5412. According to some examples, a ground conductor is electrically coupled to the fifth electrode 5310 and / or 5410.

[0325] The fifth electrode 5310 can be wider than the fourth and sixth electrodes. In some examples, the width of the fifth electrode 5310 is the same as the width of the second electrode. According to some examples, the width of the fourth electrode 5308 is the same as the width of the sixth electrode 5312.

[0326] The width of the first electrode, the width of the third electrode, the width of the fourth electrode 5308, and the width of the sixth electrode 5312 can be the same. In some examples, the fifth electrode is narrower than the fourth electrode and the sixth electrode. According to some examples, the width of the fifth electrode is the same as the width of the second electrode. The width of the fourth electrode is the same as the width of the sixth electrode. In some examples, the width of the first electrode, the width of the third electrode 4906, the width of the fourth electrode, and the width of the sixth electrode are the same.

[0327] According to some examples, the system further includes a protrusion on a side of the fifth electrode 5310 and / or 5410, the protrusion facing the fourth electrode 5308 and / or 5408. The second emitter may be rotatable. In some examples, the system further includes a protrusion on a side of the fourth electrode 5308 and / or 5408, the protrusion facing the fifth electrode 5310 and / or 5410. According to some examples, the second emitter is rotatable. The system further includes a protrusion on a side of the fifth electrode 5310 and / or 5410, the protrusion facing the sixth electrode 5312 and / or 5412. In some examples, the second emitter is rotatable. According to some examples, the system further includes a protrusion on a side of the sixth electrode 5312 and / or 5412, the protrusion facing the fifth electrode 5310 and / or 5410. The second emitter may be rotatable.

[0328] In some examples, the first emitter and the second emitter are configured to propagate pressure waves independently of each other. According to some examples, the first emitter and the second emitter are configured to generate a composite pressure wave from sequential firing of the first emitter and the second emitter. The first emitter and the second emitter can be configured to generate a composite pressure wave from timed firing of the first emitter and the second emitter.

[0329] In some examples, the third spark gap is wider than the fourth spark gap. According to some examples, the width of the first spark gap and the width of the third spark gap are the same. The width of the second spark gap and the width of the fourth spark gap can be the same.

[0330] In some examples, the ground conductor is a first ground conductor, and the system further includes a second ground conductor electrically coupled to the fifth electrode 5310 and / or 5410. According to some examples, the system further includes a third power conductor electrically coupled to the fourth electrode 5308 and / or 5408. The system can further include a fourth power conductor electrically coupled to the sixth electrode 5312 and / or 5412.

[0331] In some examples, the fifth electrode 5310 is wider than the fourth electrode 5308 and the sixth electrode 5312. According to some examples, the width of the fifth electrode 5310 and the width of the second electrode are the same. The width of the fourth electrode 5308 and the width of the sixth electrode 5312 may be the same. In some examples, the width of the first electrode, the width of the third electrode, the width of the fourth electrode 5308, and the width of the sixth electrode 5312 are the same.

[0332] According to some examples, the fifth electrode is narrower than the fourth electrode and the sixth electrode. The width of the fifth electrode and the width of the second electrode may be the same. In some examples, the width of the fourth electrode and the width of the sixth electrode are the same. According to some examples, the width of the first electrode, the width of the third electrode, the width of the fourth electrode, and the width of the sixth electrode are the same.

[0333] The system can further include a protrusion on a side of the fifth electrode 5310 and / or 5410, the protrusion facing the fourth electrode 5308 and / or 5408. In some examples, the second emitter is rotatable. According to some examples, the system can further include a protrusion on a side of the fourth electrode 5308 and / or 5408, the protrusion facing the fifth electrode 5310 and / or 5410. The second emitter can be rotatable. In some examples, the system can further include a protrusion on a side of the fifth electrode 5310 and / or 5410, the protrusion facing the sixth electrode 5312 and / or 5412. According to some examples, the second emitter is rotatable. The system can further include a protrusion on a side of the sixth electrode 5312 and / or 5412, the protrusion facing the fifth electrode 5310 and / or 5410. In some examples, the second emitter is rotatable.

[0334] According to some examples, the first emitter and the second emitter are configured to propagate pressure waves independently of each other. The first emitter and the second emitter can be configured to generate a composite pressure wave from sequential firing of the first emitter and the second emitter. In some examples, the first emitter and the second emitter are configured to generate a composite pressure wave from timed firing of the first emitter and the second emitter.

[0335] According to some examples, the third spark gap is wider than the fourth spark gap. The width of the first spark gap and the width of the third spark gap may be the same. In some examples, the width of the second spark gap and the width of the fourth spark gap are the same.

[0336] Also included in the present disclosure is a system including an inner elongated structure including a guidewire lumen. In some examples, the system includes a balloon positioned at or near a distal portion of the inner elongated structure, the balloon configured to be inflated. According to some examples, the system includes an emitter 5500, 5600, 5700, and / or 5800 positioned along the inner elongated structure and within the balloon, the emitter 5500, 5600, 5700, and / or 5800 configured to emit pressure waves to fragment deposits within the organ. The emitters 5500, 5600, 5700, and / or 5800 include first electrodes 5502, 5602, 5702, and / or 5802, second electrodes 5504, 5604, 5704, and / or 5804, and third electrodes 5506, 5606, 5706, and / or 5806, and the first electrodes 5502, 5602, 5702, and / or 5802 and the second electrodes 5504, 5604, 5704, and / or 5804 and a second spark gap 5510, 5610, and / or 5810 between the second electrode 5504, 5604, 5704, and / or 5804 and the third electrode 5506, 5606, 5706, and / or 5806.

[0337] In some examples, the first electrode 5502, 5602, 5702, and / or 5802, the second electrode 5504, 5604, 5704, and / or 5804, and the third electrode 5506, 5606, 5706, and / or 5806 each at least partially surround the inner elongated structure. According to some examples, the first electrode 5502, 5602, 5702, and / or 5802, the second electrode 5504, 5604, 5704, and / or 5804, and the third electrode 5506, 5606, 5706, and / or 5806 each wrap around the inner elongated structure.

[0338] The distance between the first electrodes 5502, 5602, and / or 5802 and the second electrodes 5504, 5604, and / or 5804 can be equal throughout the wrap of the inner elongated structure. In some examples, the distance between the second electrodes 5504, 5604, and / or 5804 and the third electrodes 5506, 5606, and / or 5806 is equal throughout the wrap of the inner elongated structure. According to some examples, the distance between the second electrodes 5604, 5704, and / or 5804 and the third electrodes 5606, 5706, and / or 5806 is less than the distance between the first electrodes 5602, 5702, and / or 5802 and the second electrodes 5604, 5704, and / or 5804.

[0339] The first electrodes 5502, 5602, 5702, and / or 5802, the second electrodes 5504, 5604, 5704, and / or 5804, and the third electrodes 5506, 5606, 5706, and / or 5806 can each be spirally wrapped around the inner extension structure. In some examples, the distance between the first electrodes 5502, 5602, and / or 5802 and the second electrodes 5504, 5604, and / or 5804 is equal throughout the wrap of the inner extension structure. According to some examples, the distance between the second electrodes 5504, 5604, and / or 5804 and the third electrodes 5506, 5606, and / or 5806 is equal throughout the wrap of the inner extension structure.

[0340] The distance between the first electrode 5702 and / or 5802 and the second electrode 5704 and / or 5804 can decrease through wrapping of the inner elongated structure. In some examples, the distance between the second electrode 5704 and / or 5804 and the third electrode 5706 and / or 5806 decreases through wrapping of the inner elongated structure. According to some examples, the first spark gap 5608 and / or 5808 is shorter than the second spark gap 5610 and / or 5810.

[0341] The system can further include a power conductor electrically coupled to the second electrode 5504, 5604, 5704, and / or 5804. In some examples, the system can further include a ground conductor electrically coupled to the first electrode 5502, 5602, 5702, and / or 5802 and the third electrode 5506, 5606, 5706, and / or 5806. According to some examples, the second electrode is narrower than the first electrode and the third electrode. The width of the first electrode and the width of the third electrode can be the same.

[0342] In some examples, the second electrodes 5504, 5604, 5704, and / or 5804 are wider than the first electrodes 5502, 5602, 5702, and / or 5802 and the third electrodes 5506, 5606, 5706, and / or 5806. According to some examples, the widths of the first electrodes 5502, 5602, 5702, and / or 5802 and the widths of the third electrodes 5506, 5606, 5706, and / or 5806 are the same.

[0343] The system can include protrusions on a side of the second electrode 5504, 5604, 5704, and / or 5804, where the protrusions face the first electrode 5502, 5602, 5702, and / or 5802. In some examples, the system includes protrusions on a side of the second electrode 5504, 5604, 5704, and / or 5804, where the protrusions face the third electrode 5506, 5606, 5706, and / or 5806. According to some examples, the system further includes protrusions on the first electrode 5502, 5602, 5702, and / or 5802, where the protrusions face the second electrode 5504, 5604, 5704, and / or 5804. The system can further include a protrusion on the third electrode 5506 , 5606 , 5706 , and / or 5806 , the protrusion facing the second electrode 5504 , 5604 , 5704 , and / or 5804 .

[0344] In some examples, the inner extension structure is flexible. According to some examples, the emitters 5500, 5600, 5700, and / or 5800 are configured to articulate from the inner extension structure flex, thereby reducing the first spark gap 5508, 5608, and / or 5808 and the second spark gap 5510, 5610, and / or 5810.

[0345] The system may further include a power conductor coupled to the first electrode 5502, 5602, 5702, and / or 5802 and the third electrode 5506, 5606, 5706, and / or 5806. In some examples, the system further includes a ground conductor electrically coupled to the second electrode 5504, 5604, 5704, and / or 5804. According to some examples, the second electrode is narrower than the first electrode and the third electrode. The width of the first electrode and the width of the third electrode are the same.

[0346] In some examples, the second electrodes 5504, 5604, 5704, and / or 5804 are wider than the first electrodes 5502, 5602, 5702, and / or 5802 and the third electrodes 5506, 5606, 5706, and / or 5806. According to some examples, the widths of the first electrodes 5502, 5602, 5702, and / or 5802 and the widths of the third electrodes 5506, 5606, 5706, and / or 5806 are the same.

[0347] The system can further include protrusions on a side of the second electrode 5504, 5604, 5704, and / or 5804, where the protrusions face the first electrode 5502, 5602, 5702, and / or 5802. In some examples, the system further includes protrusions on a side of the second electrode 5504, 5604, 5704, and / or 5804, where the protrusions face the third electrode 5506, 5606, 5706, and / or 5806. According to some examples, the system further includes protrusions on the first electrode 5502, 5602, 5702, and / or 5802, where the protrusions face the second electrode 5504, 5604, 5704, and / or 5804. The system can further include a protrusion on the third electrode 5506 , 5606 , 5706 , and / or 5806 , the protrusion facing the second electrode 5504 , 5604 , 5704 , and / or 5804 .

[0348] In some examples, the inner elongated structure is flexible. According to some examples, emitters 5500, 5600, 5700, and / or 5800 are configured to articulate from the inner elongated structure flex, thereby decreasing the width of first spark gap 5508, 5608, and / or 5808 and second spark gap 5510, 5610, and / or 5810.

[0349] Also included in the present disclosure is a system including an inner elongated structure including a guidewire lumen. In some examples, the system includes a balloon positioned at or near a distal portion of the inner elongated structure, the balloon configured to be inflated. According to some examples, the system includes an emitter 5900 and / or 6000 positioned along the inner elongated structure and within the balloon, the emitter 5900 and / or 6000 configured to emit pressure waves to fragment deposits within the organ. The emitter 5900 and / or 6000 can include a first electrode 5902 and / or 6002 and a second electrode 5904 and / or 6004 positioned to define a spark gap 5906 and / or 6006 between the first electrode 5902 and / or 6002 and the second electrode 5904 and / or 6004.

[0350] In some examples, the first electrode 5902 and / or 6002 and the second electrode 5904 and / or 6004 each at least partially surround the inner elongated structure. According to some examples, the first electrode 5902 and / or 6002 and the second electrode 5904 and / or 6004 wrap around the inner elongated structure. The distance between the first electrode 5902 and / or 6002 and the second electrode 5904 and / or 6004 can be equal throughout the wrap of the inner elongated structure.

[0351] In some examples, the first electrode 5902 and / or 6002 and the second electrode 5904 and / or 6004 are wound helically around the inner elongated structure. According to some examples, the distance between the first electrode 5902 and / or 6002 and the second electrode 5904 and / or 6004 is equal throughout the winding around the inner elongated structure. The distance between the first electrode 5902 and / or 6002 and the second electrode 5904 and / or 6004 decreases throughout the winding of the inner elongated structure.

[0352] In some examples, the system further includes a power conductor electrically coupled to the first electrode 5902 and / or 6002. According to some examples, the system further includes a ground conductor coupled to the second electrode 5904 and / or 6004. The first electrode 5902 and / or 6002 can be wider than the second electrode 5904 and / or 6004. In some examples, the second electrode 5904 and / or 6004 is wider than the first electrode 5902 and / or 6002.

[0353] According to some examples, the system further includes protrusions on the first electrodes 5902 and / or 6002. The system can further include protrusions on the second electrodes 5904 and / or 6004.

[0354] In some examples, the inner extension structure is flexible. According to some examples, the emitter 5900 and / or 6000 is configured to articulate from the inner extension structure bending, thereby reducing the spark gap 5906 and / or 6006 between the first electrode 5902 and / or 6002 and the second electrode 5904 and / or 6004.

[0355] Also included in the present disclosure is a system including an inner elongated structure 6106 defining a guidewire lumen. In some examples, the system includes a balloon positioned at a distal portion of the elongated body, the elongated body including the inner elongated structure 6106, the balloon configured to be inflated. According to some examples, the system includes an emitter 6100 positioned within the balloon along the elongated body, the emitter 6100 configured to emit pressure waves to fragment deposits within the organ. The emitter 6100 can include a first electrode 6108 and a second electrode 6110 arranged to form a spark gap between the first electrode 6108 and the second electrode 6110.

[0356] In some examples, the emitter 6100 including the first electrode 6108 and the second electrode 6110 is a first emitter 6100a, and the spark gap is a first spark gap. According to some examples, the system further includes a second emitter 6100b. The second emitter 6100b can include a third electrode 6112 and a fourth electrode 6114 arranged to define a second spark gap therebetween.

[0357] In some examples, the system further includes a first ground conductor electrically coupled to the second electrode 6110. According to some examples, the system further includes a second ground conductor electrically coupled to the fourth electrode 6114. The system may further include a power conductor electrically coupled to the first electrode 6108 and the third electrode 6112. In some examples, the first ground conductor is configured to ground the second electrode 6110 separately from the fourth electrode 6114. According to some examples, the first emitter 6100a is configured to propagate pressure waves independently from the second emitter 6100b.

[0358] The system can further include a multi-filar wire 6104, the multi-filar wire 6104 including a first ground conductor and a second ground conductor that are helically twisted and coupled to one another. According to some examples, the multi-filar wire 6104 is a multi-filar ribbon wire. The multi-filar wire 6104 may be replaced by adjacent individual unbonded wires. In some examples, the first ground conductor is configured to releasably couple from the second ground conductor when the multi-filar wire 6104 is proximate the second electrode 6110. According to some examples, the first electrode 6108 and the second electrode 6110 surround the inner elongated structure 6106. The first ground conductor and the second ground conductor can be located on an opposite side of the inner elongated structure 6106 from the power conductor.

[0359] In some examples, the system further includes a first power conductor electrically coupled to the second electrode 6110. According to some examples, the system further includes a second power conductor electrically coupled to the fourth electrode 6114. The system can further include a ground conductor electrically coupled to the first electrode 6108 and the third electrode 6112.

[0360] In some examples, the first power conductor is configured to supply power to the second electrode 6110 separately from the fourth electrode 6114. According to some examples, the first emitter 6100a is configured to propagate pressure waves independently from the second emitter 6100b.

[0361] The system can further include a multi-filar wire 6104. In some examples, the multi-filar wire 6104 includes a first power conductor and a second power conductor that are helically twisted and coupled to one another. According to some examples, the first power conductor is configured to releasably couple from the second power conductor when the multi-filar wire 6104 is proximate the second electrode 6110.

[0362] The first electrode 6108 and the second electrode 6110 can surround the inner elongated structure 6106. In some examples, the first power conductor and the second power conductor are located on opposite sides of the inner elongated structure 6106 from the ground conductor.

[0363] The section headings and subheadings provided herein are non-limiting. They do not represent or limit the full scope of the embodiments described in the section to which they relate. For example, a section entitled "Topic 1" may include embodiments unrelated to Topic 1, and embodiments described in other sections may apply to and be combined with embodiments described in the "Topic 1" section.

[0364] The various features and processes described above may be used independently of one another or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of the present disclosure. In addition, certain method, event, state, or process blocks may be omitted in some implementations. The methods, steps, and processes described herein are also not limited to any particular order, and the associated blocks, steps, or states may be performed in any other order as appropriate. For example, the described tasks or events may be performed in an order other than the order specifically disclosed. Multiple steps may be combined into a single block or state. Example tasks or events may be performed serially, in parallel, or in some other manner. Tasks or events may be added to or removed from the disclosed example embodiments. The example systems and components described herein may be configured differently from that described. For example, elements may be added to, removed from, or rearranged compared to the disclosed example embodiments.

[0365] Conditional language used herein, particularly "can," "could," "might," "may," "eg," and the like, is intended to generally convey that certain embodiments include certain features, elements, and / or steps, and other embodiments do not, unless otherwise specified or understood within the context in which it is used. Thus, such conditional language does not generally imply that features, elements, and / or steps are in some way required for one or more embodiments, or that one or more embodiments necessarily include logic for determining, with or without author input or prompting, whether those features, elements, and / or steps are to be included or performed in any particular embodiment. Terms such as "comprising," "including," and "having" are synonymous and are used inclusively, without limitation, and do not exclude additional elements, features, acts, operations, etc. Also, the term "or" is used in its inclusive sense (rather than its exclusive sense); thus, for example, when used to connect a list of elements, the term "or" means one, some, or all of the elements in the list. Conjunctive language such as the phrase "at least one of X, Y, and Z" is understood differently with the context in which it is generally used to convey that an item, term, etc. can be either X, Y, or Z, unless expressly stated otherwise. Thus, such conjunctive language does not generally imply that a particular embodiment requires that at least one of X, at least one of Y, and at least one of Z each be present.

[0366] The term "and / or" means that "and" applies to some embodiments and "or" applies to some embodiments. Thus, A, B, and / or C can be replaced with A, B, and C in one sentence and A, B, or C in another sentence. A, B, and / or C means that some embodiments can include A and B, some embodiments can include A and C, some embodiments can include B and C, some embodiments can include only A, some embodiments can include only B, some embodiments can include only C, and some embodiments can include A, B, and C. The term "and / or" is used to avoid unnecessary redundancy.

Claims

1. 1. A system comprising: an elongate structure having a guidewire lumen; an emitter positioned along the elongated structure, the emitter configured to emit pressure waves to fragment deposits within the organ; the emitter comprises a first electrode and a second electrode; the first electrode is longitudinally spaced from the second electrode to define a spark gap between the first electrode and the second electrode; the first electrode and the second electrode each at least partially surround the elongated structure; the first electrode defines a first perimeter facing the spark gap, the second electrode defines a second perimeter facing the spark gap, the first perimeter facing and parallel to the second perimeter along the entire first perimeter and the entire second perimeter; the first electrode and the second electrode are fixed in orientation relative to one another such that the first electrode is configured to generate sparks at random locations around the first circumference, thereby generating an arc discharge at the second circumference, and the first electrode and the second electrode are configured to remain fixed in orientation relative to one another while the elongated structure is traversed through a tortuous vasculature.

2. a power conductor electrically coupled to the first electrode; The system of claim 1 , further comprising: a ground conductor electrically coupled to the second electrode.

3. the emitter is a first emitter, the spark gap is a first spark gap, and the system further comprises a second emitter comprising a third electrode and a fourth electrode; the third electrode is spaced from the fourth electrode to define a second spark gap between the third electrode and the fourth electrode; The system of claim 2 , wherein the third electrode and the fourth electrode each at least partially surround the elongated structure.

4. The system of claim 3 , wherein the first spark gap is wider than the second spark gap.

5. the power conductor is a first power conductor; the system further comprising a second power conductor electrically coupled to the third electrode; The system of claim 3 , wherein the ground conductor is electrically connected to the fourth electrode.

6. The system of claim 5 , wherein the first emitter and the second emitter are configured to propagate pressure waves independently of each other.

7. The system of claim 6 , wherein the first emitter and the second emitter are configured to generate a composite pressure wave from sequential firing of the first emitter and the second emitter.

8. The system of claim 7 , wherein the first emitter and the second emitter are configured to generate a composite pressure wave from timed firing of the first emitter and the second emitter.

9. The system of claim 6 , wherein the first emitter and the second emitter are configured to generate a composite pressure wave from the simultaneous firing of the first emitter and the second emitter.

10. a multi-filar wire, the multi-filar wire including the first power conductor and the second power conductor that are helically twisted and coupled to each other; 6. The system of claim 5, wherein the first power conductor is configured to removably couple from the second power conductor when the multi-filar wire is proximate the first electrode.

11. The system of claim 5 , wherein the first power conductor and the second power conductor are located on opposite sides of the elongated structure from the ground conductor.

12. 4. The system of claim 3, wherein the ground conductor is a first ground conductor, the system further comprising a second ground conductor electrically coupled to the fourth electrode, and the power conductor is electrically coupled to the third electrode.

13. The system of claim 12 , wherein the first emitter and the second emitter are configured to propagate pressure waves independently of each other.

14. The system of claim 13 , wherein the first emitter and the second emitter are configured to generate a composite pressure wave from sequential firing of the first emitter and the second emitter.

15. 15. The system of claim 14, wherein the first emitter and the second emitter are configured to generate a composite pressure wave from timed firing of the first emitter and the second emitter.

16. The system of claim 13 , wherein the first emitter and the second emitter are configured to generate a composite pressure wave from the simultaneous firing of the first emitter and the second emitter.

17. The multi-filar wire further includes the first ground conductor and the second ground conductor, which are spirally twisted and connected to each other; 13. The system of claim 12, wherein the first ground conductor is configured to removably couple from the second ground conductor when the multifilar wire is proximate the first electrode.

18. The system of claim 12 , wherein the first ground conductor and the second ground conductor are located on opposite sides of the elongated structure from the power conductor.

21. the extension structure is an internal extension structure, and the system comprises: an outer extension structure having an inflation lumen; 10. The system of claim 1, further comprising: a balloon positioned at a distal portion of an elongate body, the elongate body comprising the inner elongate structure and the outer elongate structure, the balloon configured to receive fluid via the inflation lumen and be inflated.

22. the third electrode defines a third perimeter facing the spark gap, the fourth electrode defines a fourth perimeter facing the spark gap, the third perimeter facing and parallel to the fourth perimeter along the entire third and fourth perimeters; 4. The system of claim 3, wherein the third electrode and the fourth electrode are fixed in orientation relative to one another such that the third electrode is configured to generate sparks at random locations around the third circumference, thereby generating an arc discharge at the fourth circumference, and the third electrode and the fourth electrode are configured to remain fixed in orientation relative to one another while the elongated structure is traversed through a tortuous vasculature.

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