Intravascular lithotripsy devices and systems with forward electrodes and flexible circuit arrangements

Abstract

A catheter system generates a predominantly forward force from a forward electrode disposed within an arrangement of a balloon catheter. The system includes a high voltage pulse generator that provides positive and negative voltage connections to the electrode wires. The electrode wires may also pass through the lumen of the catheter toward a distal end of the catheter at which they are connected to electrodes, preferably arranged in series, to generate one or more energy waves that propagate toward a thrombus or calcification lesion. Expansion fluid can be conveniently injected into the balloon. The expansion fluid is preferably a salt solution such that it has a certain degree of electrical conductivity.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 416,231, filed on October 14, 2022, entitled “CATHETER SYSTEM WITH FORWARD FACING ELECTRODES FOR CREATING ENERGY WAVES,” and U.S. Provisional Application No. 63 / 462,208, filed on April 26, 2023, entitled “INTRAVASCULAR LITHOTRIPSY DEVICES AND SYSTEMS WITH FORWARD FACING ELECTRODES AND FLEX CIRCUIT ARRANGEMENTS,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The invention relates to a catheter system for treating vascular thrombosis or calcified lesions by utilizing energy waves generated by electrodes in a conductive fluid medium. Background Art

[0004] Catheter systems with angioplasty balloons are often used to apply physical force to calcified lesions within a blood vessel by inflating the balloon to force the calcified lesions back into and against the vessel wall. Some of these calcified lesions and thrombi are not effectively resolved by using angioplasty balloons. For example, thrombi may be present in the blood vessel in front of the inserted angioplasty balloon. Angioplasty balloons are not effective against forward obstruction.

[0005] Recently, an intravascular lithotripsy (IVL) catheter system has been developed that includes a balloon similar to an angioplasty balloon filled with a conductive liquid medium, such as a saline solution, for expanding the balloon at the location of a lesion or thrombus, wherein the catheter system includes a pair of electrodes operably positioned within the conductive liquid medium. The electrodes are pulsed with high voltage to generate sparks that jump across a gap between the two electrodes at each pulse. The sparks within the conductive medium generate energy waves that propagate through the liquid medium, causing the balloon to physically apply force to the lesion or thrombus. Energy propagation includes the generation of microbubbles, which also contribute to the application of physical force. Such devices are known to provide primarily radial energy waves to act radially on the lesion or thrombus, thereby achieving the purpose of destroying calcifications or clots.

[0006] Current catheter systems include treatment sequences that include a maximum number of consecutive pulses followed by a minimum delay time and a maximum total number of pulses associated with a particular catheter. The specifications for one such product are:

[0007] Frequency of treatment 1Hz (1 pulse per second) Maximum number of consecutive pulses (one cycle) 30 pulses Minimum pause time 10 seconds Maximum total pulses per catheter 300 pulses

[0008] If treatment is not complete after the maximum total number of pulses per catheter is reached, the physician must work with an assistant to change catheters, which can result in undesirable costs, delays, and disruptions.

[0009] Intravascular lithotripsy (IVL) devices are available for some calcification patterns. Disposable IVL balloon devices are available in different designs and sizes for peripheral or coronary indications. All designs use a reusable power source, such as an IVL generator. A reusable DC generator includes the following specifications:

[0010]

[0011] One such disposable device consists of a fluid-filled balloon angioplasty catheter compatible with a 0.014-inch guidewire, with two lithotripsy transmitters incorporated into the shaft of a 12 mm long balloon segment. The balloon, filled with fluid (e.g., 50 / 50 saline contrast), is inflated to about 4 atmospheres, and electrical pulses are then provided to the transmitters, which generate high-voltage sparks to deliver treatment. Sound waves are generated and calcifications are fragmented. Summary of the invention

[0012] The present invention relates to a catheter system that generates a predominantly forward force from a forward electrode disposed within an arrangement of a balloon catheter. The system includes a high voltage pulse generator that provides positive and negative voltage connections to electrode wires. The electrode wires may also pass through the lumen of the catheter toward the distal end of the catheter where they are connected to electrodes that are preferably arranged in series to generate one or more energy waves that propagate toward a thrombus or calcified lesion. An inflation fluid may be conveniently injected into the balloon. The inflation fluid is preferably a saline solution so that it has a certain degree of electrical conductivity.

[0013] In one aspect of the present invention, an intravascular lithotripsy (IVL) system is provided for providing energy waves as force to lesions within a blood vessel, the IVL system comprising a catheter extending from a proximal end to a distal end, wherein an electrode and a conductive tube are arranged at the distal end of the catheter, wherein the electrode is disposed within the conductive tube and is separated from the conductive tube by an insulating layer, the electrode having a forward electrode distal end, the conductive tube further comprising a forward conductive tube distal end, the forward conductive tube distal end being radially spaced relative to the distal end of the electrode to form at least one spark gap between the forward electrode distal ends.

[0014] The IVL system may include a plurality of electrodes within the conductive tube, each electrode being spaced apart from the conductive tube by an insulating layer, and the electrodes being electrically isolated from each other, thereby forming a plurality of gaps with the conductive tube that can be energized in series to generate a plurality of sparks. In addition, the electrodes may be arc segments of conductive material that are similarly spaced apart and coaxial with the conductive tube, and the distal ends of the electrodes and the distal ends of the conductive tube extend to similar axial lengths so as to terminate adjacent to each other.

[0015] In another aspect, the IVL system can extend the distal end of the conductive tube axially further than the distal end of the electrode so that the entire distal end of the electrode is positioned proximally within the conductive tube and spaced apart from the distal end of the conductive tube. The insulating layer can preferably extend to terminate near the distal end of the electrode so that a spark can be generated between the distal end of the electrode and the inner side wall of the conductive tube.

[0016] In another aspect of the present invention, a method of using an intravascular lithotripsy (IVL) system for intravascular lesions may include: inserting an IVL catheter having a balloon, a conductive tube, and at least one electrode into a patient's blood vessel until the lesion point is located outside the distal end of the balloon, wherein the electrode has a distal end and the conductive tube also has a distal end, thereby forming a spark gap between the electrode and the distal end of the conductive tube; electrically connecting the conductive tube and the electrode to a high-voltage pulse generator; delivering an at least partially conductive fluid to the balloon; and generating a high-voltage pulse at the high-voltage pulse generator, thereby generating a spark having a cavitation bubble at the spark gap, so that a forward energy wave propagates in the fluid of the balloon and from the balloon to the lesion.

[0017] Such an IVL system may have a plurality of electrodes within a conductive tube, each electrode being spaced apart from the conductive tube by an insulating layer, and the electrodes being electrically isolated from each other, thereby forming a plurality of spark gaps with the conductive tube, the method further comprising energizing the electrodes in series to generate a plurality of sparks at the plurality of spark gaps. The distal ends of the electrodes and the distal ends of the conductive tube extend axially for a similar distance and terminate adjacent to each other, with the insulating layer being located therebetween, such that a spark may be generated from the distal ends of the electrodes to the distal ends of the conductive tubes. Alternatively, the distal ends of the conductive tubes extend axially further than the distal ends of the electrodes, such that the entire distal ends of the electrodes are positioned proximally within the conductive tubes and spaced apart from the distal ends of the conductive tubes, the method further comprising generating a spark between the distal ends of the electrodes and the inner sidewalls of the conductive tubes, thereby generating a cavitation bubble at least partially within the distal ends of the conductive tubes, such that an energy wave may be directed in a desired forward direction from the open distal ends of the conductive tubes. More preferably, the distal ends of the conductive tubes may extend axially sufficiently beyond the distal ends of the electrodes such that the entire cavitation bubble is formed within the distal ends of the conductive tubes.

[0018] On the other hand, an intravascular lithotripsy (IVL) system is used to provide energy waves as force to lesions within a blood vessel, the IVL system comprising: a catheter extending from a proximal end to a distal end, wherein electrodes and a conductive tube are arranged at the distal end of the catheter, and a plurality of electrodes are arranged near the distal end of the catheter. The system also comprises a flexible circuit extending from the proximal end of the catheter to the electrodes, for electrically connecting the electrodes to a high-voltage pulse generator located at the proximal end of the flexible circuit, wherein the flexible circuit is within the catheter and spirally wound along at least a portion of the catheter. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of a high voltage pulse generator and a balloon catheter, including an arrangement of electrodes and a conductive tube, for generating a forward (in the axial direction) spark as an intravascular lithotripsy (IVL) device;

[0020] Figure 2 is similar to Figure 1 but with an open-ended balloon to allow conductive fluid to flow out of the balloon during an IVL procedure;

[0021] Figure 3 is a perspective view of a distal portion of a conductive tube in which a pair of arcuate electrodes are positioned to form an IVL device, but without showing an insulating layer;

[0022] Figure 4 is a cross-sectional view of the distal portion of the IVL device showing the two electrodes and the end of the conductive tube where the spark will be generated and cause axial forward energy propagation;

[0023] Figure 5 is similar to Figure 4 a cross-sectional view of a conductive tube extending further in an axial forward direction than the end of the electrode so that energy generated from the spark propagates slightly radially inward;

[0024] Figure 6 Shows Figures 1 to 5 A cross-section of a distal portion of an IVL device in , showing that the conductive electrode and the conductive tube are insulated from each other;

[0025] Figure 7 is a cross-section of a flexible circuit portion including an insulating layer, wherein a plurality of electrodes are rolled up and inserted into a conductive tube to provide an electrode structure according to the present invention;

[0026] Figure 8 Yes Figure 7 a cross section of the resulting electrode arrangement of the flexible circuit in;

[0027] Fig. 9 is another flexible circuit arrangement comprising a conductive layer, an insulating layer, and a plurality of electrodes suitable for forming the electrode structure of the present invention;

[0028] Fig.10 Yes Fig. 9 a cross-section of a resulting electrode arrangement of a flexible circuit wrapped around a lumen defining a tube;

[0029] Fig.11 is with Fig. 9 A flex circuit similar to that shown, but shortened so that it is not as long as the circumference of the lumen defining the tube;

[0030] Fig.12 is a cross-section of a flexible circuit partially wrapped around a lumen defining a tube;

[0031] Fig.13 is a view of a portion of a flexible circuit having a plurality of electrode pads connected to traces for electrical connection and power delivery;

[0032] Fig.14 Similar to Fig.13 , showing the spark generated from the electrode pad to the conductive outer layer;

[0033] Fig.15 is a distal portion of an electrode pad connected to a trace that is angled to effect a helical winding of the trace to extend from the electrode pad and along the length of the catheter;

[0034] Fig.16 Is suitable for Fig.15 The length of the electrode pads and angled traces shown for winding;

[0035] Fig.17 is a distal portion of an electrode having a plurality of traces extending from an electrode pad, and the traces may also be wound as they extend;

[0036] Fig.18 is similar to Fig.16 , showing a pair of electrical conductors disposed along one side of a single trace for connection with a pair of electrode pads;

[0037] Fig.19 yes Fig.18 an enlarged view of the traces, conductors, and distal portions of the electrode pads;

[0038] Fig. 20 is with Fig.18 A similar view showing a pair of electrical conductors disposed along either side of a single trace for connection to a pair of electrode pads;

[0039] Fig.21 yes Fig. 20 an enlarged view of the traces, conductors, and distal portions of the electrode pads;

[0040] Fig. 22is a view of a pair of electrodes and the length of the trace, having a pair of linearly extending conductors for connection with a high voltage pulse generator;

[0041] Fig.23 yes Fig. 22 an enlarged distal portion of electrodes, conductors, and traces of a flexible circuit;

[0042] Fig.24 is similar to Figure 5 wherein the conductive tube extends further in an axial forward direction than an end of the electrode so that a spark is generated between the end of the electrode and an inner wall of the conductive tube for propagating an energy wave from the end of the conductive tube; and

[0043] Fig.25 yes Fig.24 A transverse cross-sectional view of a conductive tube and electrode arrangement showing a single electrode as a coaxial conductive tube within an outer conductive tube. DETAILED DESCRIPTION

[0044] The present invention relates to a Figure 1 A schematic diagram of a catheter system 10 is shown that generates a primarily forward force from forward electrodes 12 and 14, as described below. The system 10 includes a high voltage pulse generator 16 that provides positive and negative voltage connections to electrode wires 18 and 20. A catheter 22 includes a wire guide 24 at a proximal end and a balloon 26 at a distal operative end. The wire 28 slides within a lumen 30 extending from an entry port 32 of the wire guide 24 to the distal end of the balloon 26. The electrode wires 18 and 20 may also be passed through the lumen 30 toward the distal end of the catheter 22 through an electrical inlet 34 of the wire guide 24. An inflation fluid may be conveniently injected into the balloon through an inflation inlet 36, and fluid flow through the catheter 22 may be provided by any inflation lumen as is known for use with a balloon 26. The inflation fluid is preferably a saline solution so that it has a certain degree of conductivity for the purposes described below.

[0045] As shown within balloon 26, electrode wires 18 and 20 are electrically connected to electrodes 12 and 14, respectively. Electrode 12 is preferably separated from wire lumen 30 by a first insulating layer 38, which surrounds and may define lumen 30. A second insulating layer 40 preferably surrounds electrodes 12 and 14 to electrically insulate electrodes 12 and 14 from conductive tube 42. Figure 3As best schematically shown in , each electrode 12 and 14 may preferably be disposed in the same radial space as the lumen 30. As shown, the electrode 12 is arcuate when viewed from its distal or proximal end and includes an arc segment, preferably less than 180 degrees, and extends axially for a predetermined length and is connected to the electrode wire 20. Similarly, the electrode 14 is arcuate when viewed from its distal or proximal end and includes another arc segment, preferably also less than 180 degrees, and extends axially for a predetermined length and is connected to the electrode wire 18. The electrodes 12 and 14 may have similar or different lengths. The lengths of the electrodes 12 and 14 may be related to their service life because they will wear over time, as described in more detail below. The conductive tube 42 is schematically positioned to surround the two electrodes 12 and 14 in a preferably concentric manner.

[0046] Figure 3 1 and 2. Insulating layers 38 and 40 are not shown in the drawings. Layer 38 is located between lumen 30 and electrodes 12 and 14, preferably also as a concentric layer. Layer 40 is located between electrodes 12 and 14 and conductive tube 42, preferably also as a concentric layer. Although the arc segments of electrodes 12 and 14 are both less than 180 degrees, gaps 44 and 46 are formed between the corresponding axial edges on each side of the two electrodes 12 and 14. Preferably, the gaps are similar in arc segment length, but this is not necessary. In order to prevent any arcing between electrodes 12 and 14 at gaps 44 and 46, it is also preferable to provide insulating material of insulating layers 38 or 40 or both to fill gaps 44 and 46.

[0047] Reference again Figure 1 , the distal ends of the electrodes 12 and 14 are where the electrode sparks are controllably actuated by the high voltage pulses generated by the generator 16. The controller 48 is schematically shown in operative connection with the high voltage pulse generator 16, and may include an operator input module so that the operator can control the pulses and therefore the sparks across the electrodes 12 and 14 and the conductive tube 42. The controller 48 may also include programming to control the high voltage pulses according to a predetermined sequence, which may be customized for a particular vascular condition or other condition.

[0048] For each high voltage pulse, multiple sparks are preferably generated. Figure 1-Figure 5In the example of , a positive charge can be provided from a high voltage pulse generator 16 to the electrode 14 via the electrode wire 20 as a single pulse or a series of controlled pulses. A neutral or grounded ground can be applied from the generator 16 to the electrode 12 via the electrode wire 18. Thus, for each pulse, a spark will form an arc from the distal surface of the electrode 14 to the distal surface of the conductive tube 42. The charge provided to the conductive tube 42 will produce a second spark as an arc from the conductive tube 42 to the neutral electrode 12. In this way, the spark gaps are electrically connected in series. As described above, in the process the balloon 26 is filled with a fluid medium, wherein the fluid medium is at least partially conductive, such as a saline solution. Other fluid media known or developed may also be used. Figure 1 The dashed arrows at the distal end of the electrodes 12 and 14 and the conductive tube 42 illustrate the arc. Figure 3 and Figure 4 In the figure, the propagation of energy is represented by the dotted line.

[0049] According to a preferred aspect of the present invention, each spark or arc occurs from the forward surface of each of the electrodes 12 and 14 and the conductive tube 42. More preferably, the forward surface is located at the distal end of the electrodes 12 and 14 and the conductive tube 42. In order to prevent sparks from being generated on the proximal side of the electrodes, an insulating material may also be applied to cover the proximal or rearward surfaces of the electrodes 12 and 14. Due to this orientation, each spark generates an energy wave that propagates in a forward direction, which is defined as the main axial direction from the distal end of the electrodes 12 and 14 and the conductive tube 42. In operation, the catheter 22 will be inserted into a blood vessel so that the balloon 26 abuts against a thrombus or other calcified lesion, wherein the distal portion of the balloon 26 can be deformed against such a thrombus or lesion. Therefore, the high voltage pulse will generate one or a series of energy waves that propagate through the fluid medium in the balloon 26 in the forward direction to apply one or a series of forces to the thrombus or lesion to break it up.

[0050] Each time a spark is ignited and generated between the electrodes 12 and 14 and the conductive tube 42, a portion of the respective forward surface of each will disintegrate at the closest point. Thus, the spark will move from one point to a new closest point or minimum gap between these forward surfaces. Thus, the spark will travel between the axial edges of the electrodes 12 and 14 along the arcuate forward surfaces of the electrodes 12 and 14 and the conductive tube 42. Over time, the electrodes 12 and 14 and the conductive tube 42 will wear along the arcuate forward surfaces of the electrodes 12 and 14 and the conductive tube 42 and axially. The service life of the electrodes 12 and 14 and the conductive tube 42 can be based on the axial wear length determined to be acceptable.

[0051] Figure 2 Shown with Figure 1A substantially similar catheter embodiment, but the distal end of the balloon 126 is open (as indicated at 127) through which a fluid medium may pass. In operation, the fluid will be supplied at a certain pressure to induce axial flow (fluid flow indicated by the arrow) from the distal end of the balloon 126, while sparks and energy waves are generated from the high pressure pulse. This fluid flow can help to break up the thrombus or lesion. The fluid flow can be controlled to be minimal, such as to allow it to seep through the open end at 127, or the fluid flow can be controlled to supplement the impact on the thrombus or lesion. In this case, the microbubbles generated in the fluid by the energy wave can pass through the open end 127 to interact with the thrombus or lesion. As shown in reference Figure 1 , Figure 3 and Figure 4 All other components and features discussed are similar but are labeled with like reference numerals with 1 in the hundreds place.

[0052] Figure 5 Another example of a forward electrode arrangement is shown for generating an energy wave that propagates primarily in an axial or forward direction. In this example, the distal end of at least a portion of the conductive tube 42 and the forward surface thereof extend axially beyond the forward surface of the electrode 14. The axial distance that the conductive tube extends beyond the forward surface of the electrode 12 and / or the electrode 14 can vary depending on the desired directional control of the spark. The insulating layer 40 can also extend from the distal end of the conductive tube 42 and bevel to the electrode 14, although this is not necessary. The spark can be generated between the end of the conductive tube 42 and the end of the electrodes 12 and 14, as described above, or the spark can be generated from the inner surface of the conductive tube slightly near its distal end. With this arrangement, the spark will be generated primarily in the forward and axial direction, but the energy wave will still propagate slightly radially inward, as shown in the waveform diagram. It is conceivable that the entire circumference of the conductive tube 42 can be extended distally and forwardly compared to both electrodes 12 and 14, so that the two sparks will propagate similar waveforms, which are primarily forward and slightly radially inward. It is also conceivable that the opposite arrangement can be made. One or both of the electrodes 12 and / or 14 may extend forward of the distal end of the conductive tube 42. In this arrangement, one or both energy waves may propagate primarily in a forward or axial direction while also propagating slightly radially outward. One energy wave may propagate primarily forward and radially inward, combined with another energy wave propagating primarily forward and radially outward. Furthermore, as described above, any combination of forward energy waves may be combined with another energy wave propagating primarily forward and radially inward or outward.

[0053] Fig.24 and Fig.25, which is also used to generate energy waves that propagate primarily in the axial forward direction. In this arrangement, the outer conductive tube 42' extends axially farther than the single inner tube electrode 12'. The insulating layer 40' preferably extends to a similar extent as the electrode 12'. Similarly, the insulating layer 38' preferably also extends to a similar extent as the electrode 12' and forms a lumen 30' for the wire. The single electrode 12' is shown as a conductive tube concentric with the outer conductive tube 42' and will be electrically connected to the positive conductor or negative conductor from the high-voltage pulse generator 16, wherein the outer conductive tube 42' is electrically connected to the other of the positive conductor or negative conductor from the high-voltage pulse generator 16. In this way, a spark S can be generated between the electrode 12' and the distal portion of the outer conductive tube 42'. As shown in the figure, the spark S and the generated cavitation bubble will preferably appear at least partially (and more preferably completely) in the distal portion of the outer conductive tube 42', wherein the spark S is located between the end face of the electrode 12' and the inner wall surface of the outer conductive tube 42'. With this arrangement, the spark S will at least partially (and more preferably completely) generate cavitation bubbles (or microbubbles) within the distal end of the conductive tube 42', which will directionally direct or manage the released energy in a forward direction as an energy wave exiting the opening of the outer conductive tube 42' and reaching the lesion. Surprisingly, for most applications, this can be achieved without destroying the catheter components. The spark S will generate an energy wave, preferably at least partially within the distal end of the outer conductive tube 42', to propagate from the distal end of the outer conductive tube 42'. In addition, the cavitation of the microbubbles within the distal portion of the outer conductive tube 42' will increase the energy wave generated and propagated from the distal end of the conductive tube 42. It is contemplated that multiple electrodes may also be used in a similar arrangement, for example Figure 5 A modification of the arrangement shown in .

[0054] It is also contemplated that more than two such electrodes may be provided. Depending on the number of such electrodes, additional conductive tubes may be required to provide a conductive sequence with a controlled spark at a defined gap.

[0055] Figure 6 Shows Figures 1 to 42 is a cross-section of an electrode and conductive tube arrangement in FIG. The conductive tube 42 is shown as a seamless tube, also known as a hypotube, which is concentric with the wire tube 29, which defines a lumen 30 through which the wire 28 can pass. In this arrangement, the tube 29 provides insulation on one side of the electrodes 12 and 14 without the first insulating layer 38 described above. The electrodes 12 and 14 are located in a common radial space and are abutted against the outer surface of the tube 29 in the form of arc segments. The second insulating layer 40 is shown as being located between the conductive tube 42 and the outer curved surfaces of the electrodes 12 and 14 and filling the gaps 44 and 46 between the axially extending edges of the electrodes 12 and 14. This arrangement can be made in a variety of ways, such as providing a tube 29 and adhering, welding or otherwise supporting the electrodes 12 and 14 on the outer surface of the tube 29. This subassembly may then be supported concentrically in position on outer conductive tube 42 , and insulating material may then be injected within gaps 44 and 46 between conductive tube 42 , the outer surfaces of the respective electrodes 12 and 14 , and portions of the outer surface of tube 29 .

[0056] Figure 7 and Figure 8 Together, we show how to make something similar to Figures 1 to 4 The arrangement of electrodes and conductive tubes. Figure 7 As shown, electrodes 212 and 214 can be formed as a flexible circuit together with an insulating layer 240. The flexible or flex circuit 227 can be made by well-known processes, which may include material addition or removal steps and masking steps and controlled deposition and / or etching steps. As is well known, flexible circuits are used to combine conductive metals (such as electrical traces, pads or electrodes) with insulating layers and potential other supporting materials, and are used for electrical interconnection of components. In this example, the insulating layer 240 and electrodes 212 and 14 are formed as a flat flexible circuit 227 subassembly, which can then be wrapped around the lumen 230 defining the tube 229, bonded, welded or otherwise attached to the tube 229, and then inserted into the conductive tube 242. The conductive tube 242 can be bonded, welded or otherwise attached to the flexible circuit 227, or it may not be attached. The electrodes 212 and 214 and the insulating layer 240 must be flexible enough to be able to be rolled up as shown. Electrodes 212 and 214 are positioned in a flat state along the face of insulating layer 230 so that when rolled around tube 229, they will be positioned as desired, preferably in a position such as Figure 8 The flat flexible circuit extends from a first axially extending edge 231 (when rolled) to a second axially extending edge 233. When wrapped around the tube 229, a gap 235 is preferably formed between the ends 231 and 233 to ensure that the electrodes 212 and 214 are properly positioned and do not engage or interfere with each other.

[0057] exist Fig. 9 and Fig.10Another way to make such an electrode and conductive tube arrangement is shown in FIG. Fig. 9 As shown, an alternative flexible circuit 327 is formed, which includes a conductive layer 342, an insulating layer 340, and electrodes 312 and 314 embedded in the insulating layer 240. In this case, not only must the electrodes 312 and 314 and the insulating layer 340 be flexible enough to be rolled up, but the conductive layer 342 must also be so. In order to form the electrode and conductive tube arrangement, Fig. 9 The flexible circuit 327 can be wrapped around the outer surface of the tube 329 and fixed in place by adhesive, welding or other means. The flat flexible circuit 327 extends from a first axially extending edge 331 (when rolled) to a second axially extending edge 333. When wrapped around the tube 329, a gap 335 is preferably formed between the ends 331 and 333 to ensure that the electrodes 312 and 314 are properly positioned and do not engage or interfere with each other.

[0058] exist Fig.11 and Fig.12 , another way to make another electrode and conductive tube arrangement of this type is shown. In this arrangement, the flexible circuit 427 is made to be wrapped only partially around the lumen 430 defining the tube 429 and fixed in place. Specifically, a flexible circuit is formed that includes a conductive layer 442, an insulating layer 440, and electrodes 412 and 414. Also in this arrangement, the electrodes 412 and 414 and the insulating layer 440 must be flexible enough to be rolled up with the conductive layer 442. In order to form the electrode and conductive tube arrangement, Fig.11 The flexible circuit 427 can be partially wrapped around the outer surface of the tube 429 and fixed in place, such as by adhesive, welding or other means. The flat flexible circuit 427 extends from a first axially extending edge 431 (when rolled) to a second axially extending edge 433. When partially wrapped around the tube 429, a gap 435 is preferably formed between the ends 431 and 433 to ensure that the electrodes 412 and 414 are properly positioned and do not engage or interfere with each other. This arrangement can reduce material requirements while effectively providing preferably diametrically opposed electrodes 412 and 414 in an operating position relative to the conductive layer 442.

[0059] Fig.13 and Fig.14Another advantage of forming an electrode and conductive tube arrangement from a flexible circuit is shown. As shown, a flexible circuit 527 can be manufactured, which includes an insulating layer 540, on which electrical traces 518 and 520 can be formed, as described above. The electrical traces 518 and 520 can extend axially and terminate at or near the distal end of the insulating layer 540 as pads shown as rectangles, which can form electrodes 512 and 514. The flexible circuit 527 can be applied to the conductive material layer 542 by any known bonding technology. When rolled up, the electrical traces 518 and 520 extend axially along the tube formed by the rolled conductive material 542. The flexible circuit 527 and the conductive material 542 can be wrapped around the outer surface of the insulating tube (not shown, but similar to the tube 29) and also bonded in place. The electrical traces 518 and 520 can advantageously extend beyond the proximal end of the insulating layer 540 and / or the conductive material 542, possibly extending through the wire device 24 all the way to the outside. With such an arrangement, there is no need to make any electrical connections within the balloon or anywhere along the catheter. Not making electrical connections within the balloon will allow the balloon and electrodes / conductive tubes to have a lower profile within the patient.

[0060] Fig.14 Sparking is shown between the distal end of each electrode 512 and 514 and the distal end of the conductive material 542. As described above, the sparking can be controlled by the relative extension of the electrodes 512 and 514 and the conductive material 542 and the insulating material 540 to make it more radial or axial.

[0061] Other flexible circuits are contemplated that may facilitate easier extension of the flexible circuit to the electrodes along the length of the catheter and preferably with minimal effect on the stiffness of the catheter, thereby allowing for desired positioning of the IVL balloon within the patient's vessel. As described above, preferably two conductors may electrically connect any number of transmitters in series, each transmitter comprising two electrodes. Thus, a flexible circuit design may include two electrical traces on an insulating flexible layer to extend from a high voltage pulse generator to one or more transmitters of an IVL balloon.

[0062] The following embodiments of a flexible circuit according to the present invention relate to providing a pair of electrodes at the distal end of the flexible circuit, such as may be used in a forward IVL launcher as described above. However, it is also contemplated that a flexible circuit according to the present invention may alternatively be used in designs other than axial firing designs, wherein the distal end of the flexible circuit conductor may include electrodes, or may provide bonding pads or other electrical connections or connectors that may be connected to any other electrode design. Such bonding pads may be used in other axial firing launcher designs, radial firing launcher designs, or other designs. Therefore, in the following description, the term electrode may be interpreted as actually including electrodes according to an IVL device or bonding pads or other electrical connections or connectors that may be connected to electrodes of an IVL device.

[0063] exist Fig.15 and Fig.16 , a flexible circuit 600 is shown that is intended to be wound helically along the length of a catheter as part of an IVL device. A distal pad 602 is shown having an extension 604 extending proximally therefrom at an angle to form a helical wrap. The angle may be based on the width of the flexible circuit 604 so as to wrap within and along the distance of the catheter (not shown), preferably without any overlapping wraps. Fig.15 An initial wrap is shown, which is located near the distal end of the distal pad 602 and the flexible circuit 604. The distal pad 602 and the extension portion 604 may include a plurality of (preferably two) electrical traces and electrodes or pads, which may be manufactured by any flexible circuit production process as described above or otherwise developed (discussed in more detail below). Such electrical traces may extend to the distal end of the flexible circuit to terminate at the proximal pad portion 606 for electrical connection to the high voltage pulse generator, as described above. It is contemplated that a control system or module may also be provided at the connection to the high voltage pulse generator for controlling the actuation of the high voltage pulses and for use in the IVL process.

[0064] Fig.17 Shown with Fig.15 and Fig.16 Similar concept but with multiple (preferably two) extensions 603 and 605 extending at similar angles from the distal pad 601. Also shown are these same components in the rolled-up state of the distal pad 601 and the beginning of the multiple wraps of the extensions 603 and 605 as they extend within and along the length of the IVL catheter.

[0065] exist Fig.18 and Fig.19 middle, Fig.15 and Fig.16 The flexible circuit 600 is shown with electrical traces 608 and 610 extending from proximal electrical bonding pads 612 and 614 provided on the proximal pad 606 to distal electrodes or bonding pads 616 and 618 provided on the distal pad 602. Thus, the electrical conductor extends from the proximal pad 606 to the distal pad 602, including bonding pads 612 and 614, traces 608 and 610, and electrodes or bonding pads 616 and 618, respectively. An insulating layer is also provided along with the electrical conductor, including the proximal pad 606, the extension 604, and the distal pad 602. Preferably, the traces 608 and 610 are spaced apart from each other so as not to electrically interfere with each other and not to cause insulation breakdown therebetween during a high voltage pulse or during any expected use time of the IVL system. Preferably, conjugate pads 612 and 614 and electrodes or conjugate pads 616 and 618 may be sufficiently spaced apart from one another, as provided on proximal pad 606 and distal pad 602, as such pads may be larger than the width of extension 604 to accommodate even larger conjugate pads or electrodes.

[0066] Fig. 20 and Fig.21 Another embodiment of a flexible circuit 700 according to the present invention is shown. Similar to the flexible circuit 600, the insulating layer may include a proximal pad 706, an extension 704, and a distal pad 702. In this case, a first electrical trace 710 may extend along one side (front) of the insulating layer, and a second electrical trace 708 may extend along the other side (back) of the insulating layer. To this end, a bonding pad 712 may be provided on a first side of the proximal pad 706, which is electrically connected to the trace 710 and is also electrically connected to a distal electrode or bonding pad 716. The electrical trace 708 may then extend along the second side and be formed or connected with a proximal bonding pad 714 and a distal electrode or bonding pad 718. The proximal and distal bonding pads or electrodes 714 and 718 may be provided on the second side of the insulating layer or on the first side of the insulating layer. In the latter case, an electrical via may connect one or both of the proximal bonding pad 714 and the distal electrode or bonding pad 718 to the trace 708. Where electrodes are provided at 716 and 718 (eg, for a forward firing arrangement), it is preferred that both electrodes be provided on the same side of the distal pad 702 . Fig. 20 and Fig.21 The top (blue) trace portion of trace 708 is shown, which only partially follows each of the proximal pad 706 and the distal pad 702, and is connected by an electrical via to the remainder of the trace 708 extending along the second side of the insulator. The advantage of this design is better insulation between traces 708 and 710, while allowing the extended portion 704 of the flex circuit to be narrower for easier winding.

[0067] Fig. 22 and Fig.23 Another flexible circuit according to the present invention is shown. Flexible circuit 800 is similar to Fig.18 and Fig.19 , but lacks the distal pad for accommodating electrodes or bonding pads 816 and 818. In this embodiment, traces 808 and 810 extend side by side on one surface of the insulating layer along an extension portion 804 between the proximal pad 806 and the distal end. Traces 806 and 810 are spaced further apart from one another as they extend along the extension portion 804 of the flexible circuit 800 to provide better insulation between the traces during high voltage pulses. The larger width of the extension portion 804 provides sufficient space for traces 808 and 810 to be further spaced apart. However, this larger width of the extension portion 804 may make it difficult to form a spiral wrap when positioning the flexible circuit 800 within and along the IVL catheter. In this case, the flexible circuit 800 can simply extend along the IVL catheter without wrapping. Fig.23 As shown, electrodes may be provided at 816 and 818 with a spacing similar to that of traces 808 and 810, but this need not be the case.

[0068] It should also be understood that assemblies or subassemblies such as the above-described flexible circuits can be manufactured using other means other than flexible circuit technology, such as by manufacturing each component separately and then assembling. Other arrangements are contemplated having two or more electrodes and any number of conductive layers or tubes. Although it is preferred that the electrode and conductive tube or layer arrangement produces primarily forward or axial energy wave propagation, it is contemplated that the arrangement can produce energy wave propagation that is more radial than axial, but preferably has at least an axial component.

[0069] It will also be appreciated that the electrode and conductive tube arrangement need not be limited to cylindrical shapes. The electrode is preferably shaped similar to the spaced portion of conductive material, preferably a tube or portion of a tube, which may be circular or a portion of a circle in cross-section, or may be other shapes such as square, rectangular, hexagonal, etc. As described above, by controlling the spacing of the electrode and the similarly shaped conductive wall portion, the spark will jump similar gaps and will travel along the leading edge from side to side as the electrode, along with the conductive wall portion, wears over time. Preferably, the tube or portion thereof may be electrically connected in series with the spark gap created by the spacing.

Claims

1. An intravascular lithotripsy (IVL) system for providing energy waves as force to a lesion within a blood vessel, the IVL system comprising: A catheter extending from a proximal end to a distal end, wherein an electrode and a conductive tube are arranged at the distal end of the catheter, wherein the electrode is disposed within the conductive tube and is spaced apart from the conductive tube by an insulating layer, the electrode having a forward electrode distal end, the conductive tube further comprising a forward conductive tube distal end, the forward conductive tube distal end being radially spaced apart from the distal end of the electrode to form at least one spark gap between the forward electrode distal ends.

2. The IVL system according to claim 1, wherein a plurality of electrodes are arranged in the conductive tube, each electrode is separated from the conductive tube by the insulating layer, and the electrodes are electrically isolated from each other, thereby forming a plurality of gaps with the conductive tube, and the plurality of gaps can be energized in series to generate a plurality of sparks.

3. The IVL system of claim 2, wherein the electrode is an arc segment of conductive material that is spaced apart from and coaxial with the conductive tube in a similar manner, and the distal end of the electrode and the distal end of the conductive tube extend to similar axial lengths so as to terminate adjacent to each other.

4. The IVL system of claim 4, wherein the insulating layer extends in a similar manner to terminate near the distal ends of the electrode and the conductive tube, and a wire insulating layer is provided inside the electrode to define a wire lumen.

5. The IVL system of claim 1, wherein the distal end of the conductive tube extends axially further than the distal end of the electrode, such that the entire distal end of the electrode is positioned proximally within the conductive tube and spaced apart from the distal end of the conductive tube.

6. The IVL system of claim 5, wherein the insulating layer extends to terminate near the distal end of the electrode so that a spark can be generated between the distal end of the electrode and the inner side wall of the conductive tube.

7. The IVL system of claim 1, wherein the electrodes and the insulating layer comprise a flexible circuit that can be rolled into a cylinder and inserted into the conductive tube.

8. The IVL system of claim 7, wherein the conductive tube is also formed as part of the flexible circuit.

9. A method of using an intravascular lithotripsy (IVL) system for intravascular lesions, comprising: Inserting an IVL catheter having a balloon, a conductive tube and at least one electrode into a blood vessel of a patient until the lesion point in the blood vessel is located outside the distal end of the balloon, wherein the electrode has a distal end and the conductive tube also has a distal end, thereby forming a spark gap between the electrode and the distal end of the conductive tube; electrically connecting the conductive tube and the electrode to a high voltage pulse generator; delivering an at least partially electrically conductive fluid to the balloon; as well as A high voltage pulse is generated at the high voltage pulse generator, thereby generating a spark with a cavitation bubble at the spark gap, so that a forward energy wave propagates within the fluid of the balloon and from the balloon to the lesion.

10. The IVL system of claim 9, wherein a plurality of electrodes are disposed within the conductive tube, each electrode being separated from the conductive tube by an insulating layer, and the electrodes are electrically isolated from each other to form a plurality of spark gaps with the conductive tube, the method further comprising energizing the electrodes in series to generate a plurality of sparks at the plurality of spark gaps.

11. The IVL system of claim 10, wherein the distal end of the electrode and the distal end of the conductive tube extend axially a similar distance and terminate adjacent to each other, and the insulating layer is located between the electrode and the conductive tube so that sparks can be generated from the distal end of the electrode and the distal end of the conductive tube.

12. The IVL system of claim 9, wherein the distal end of the conductive tube extends axially further than the distal end of the electrode, such that the entire distal end of the electrode is positioned proximally within the conductive tube and spaced apart from the distal end of the conductive tube, the method further comprising generating a spark between the distal end of the electrode and an inner sidewall of the conductive tube, thereby generating a cavitation bubble at least partially within the distal end of the conductive tube, enabling an energy wave to be directed from the open distal end of the conductive tube in a desired forward direction.

13. The IVL system of claim 12, wherein the distal end of the conductive tube extends axially sufficiently beyond the distal end of the electrode such that the entire cavitation bubble is formed within the distal end of the conductive tube.

14. An intravascular lithotripsy (IVL) system for providing energy waves as a force to a lesion within a blood vessel, the IVL system comprising: A catheter extending from a proximal end to a distal end, wherein an electrode and a conductive tube are arranged at the distal end of the catheter, and a plurality of electrodes are arranged near the distal end of the catheter. The system also includes a flexible circuit extending from the proximal end of the catheter to the electrodes, for electrically connecting the electrodes to a high-voltage pulse generator located at the proximal end of the flexible circuit, wherein the flexible circuit is spirally wound within the catheter and along at least a portion of the catheter.

15. An IVL system according to claim 14, wherein the electrode is formed on a flexible pad portion at the distal end of the flexible circuit, and an extension portion of the flexible circuit extends proximally from the flexible pad within the catheter, the extension portion of the flexible circuit further having a plurality of conductive traces extending along the extension portion.

16. The IVL system of claim 15, wherein the extension extends from the flexible pad at an angle such that the trace is arranged at the angle relative to the positioning of the electrode to facilitate helical winding of the extension within and along the catheter.

17. The IVL system of claim 15, wherein a plurality of traces are disposed along a side surface of the extended portion of the flexible circuit.

18. The IVL system of claim 15, wherein at least one trace is configured to extend along one side surface of the extension portion of the flexible circuit, and at least another trace extends along a second side surface of the extension portion of the flexible circuit.

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