Intravascular lithotripsy device and system with thin-walled balloon

Abstract

Improved IVL systems and components with reduced tendency to malfunction caused by undesired electrical arcs and / or currents and / or plasma discharges between the IVL emitter and the deployed balloon. Additionally or alternatively, the present invention provides improved IVL systems and components with reduced tendency to malfunction caused by the possibility of undesired electrical discharges and / or electrical arcs and / or currents between the deployed balloon and tissue. This undesired flow of energy can occur during the delivery of the treatment, but can also occur during or at the end of a treatment pulse due to charging of the fluid solution within the balloon over time and its effects outside the balloon.

Description

[Technical Field]

[0001] This application claims priority to and benefit of U.S. Provisional Application No. 63 / 425,169, filed November 14, 2022, entitled "INTRAVASCULAR LITHOTRIPSY DEVICES AND SYSTEM," the entire contents of which are incorporated herein by reference.

[0002] An intravascular lithotripsy catheter for use in intravascular medical procedures. [Background technology]

[0003] Calcification of blood vessels interferes with proper blood flow and is associated with adverse health outcomes, including severe blood flow restriction. Calcification can range from mild to severe, and the pattern of calcification can vary widely.

[0004] One successful method to mitigate the deleterious effects of calcification is orbital atherectomy. Although it has proven highly successful and is considered the gold standard for addressing difficult calcification problems, other options are available to surgeons for less challenging calcification patterns.

[0005] For some calcification patterns, intravascular lithotripsy (IVL) devices are available. Disposable IVL balloon devices are available in a variety of designs and sizes for peripheral or coronary indications. All designs utilize a reusable power source, such as an IVL generator. Some reusable generators have the following specifications:

[0006] [Table 1]

[0007] For some calcification patterns, intravascular lithotripsy (IVL) devices are available. Disposable IVL balloon devices are available in a variety of designs and sizes for peripheral or coronary indications. All designs utilize a reusable power source, such as an IVL generator. Some reusable generators have the following specifications:

[0008] One such disposable device consists of a fluid-filled balloon catheter, compatible with a 0.014-inch guidewire, with two lithotripsy emitters embedded in the shaft of a 12-mm-long balloon. The fluid-filled balloon (e.g., 50 / 50 saline-contrast agent) is inflated to approximately 4 atmospheres of pressure, and then an electrical pulse is delivered to the emitters, which generate a high-voltage spark to deliver the therapy. Acoustic waves are generated, causing calcium to break down.

[0009] Reported details of known IVL balloons include the features shown in FIG. 9. Specifically, an exemplary effective length of such an IVL catheter balloon zone is defined by marker bands, with emitters spaced apart between the marker bands. Different spacings can be provided between pairs of emitters, as can the spacing from the emitters to the marker bands. Also shown is the balloon's energy profile, which is shown as a smooth energy profile across the central portion of the balloon. A placement scheme for emitters to create an optimized overlap zone is also shown.

[0010] Balloon lifespan and durability are well-known issues with currently available IVL devices. The maximum number of pulses is tied to the specific design; some devices limit the number of pulses to 300, while others limit the number of pulses to 160 per balloon and even fewer per electrode. After pulses well below this limit, harmful materials can be found in the saline-filled balloon due to the electrical pulses and the energy generated (bubble generation, collapse, heat, and shock waves). The number of pulses is controlled; in one example, the maximum number of consecutive pulses is 30, with a minimum pause time of 10 seconds.

[0011] Balloons for IVL systems are constructed from tough materials such as nylon and PEBAX. One such system was known as the S4 system, available from Shockwave Medical of Santa Clara, California. The manufacturer originally equipped its system with a much thinner balloon, which malfunctioned during human use. The manufacturer recalled the S4 system and stated that the recall of the S4 catheter was based on the balloon's inability to maintain inflation due to suboptimal wall thickness in at least some sizes. The current thickness of the S4 system balloon is believed to have roughly doubled to approximately 0.0009 inches.

[0012] Efforts have been made to improve the integrity of the balloons in IVL systems, see for example U.S. Patent Application Publication No. 2021-0378743, which describes balloon integrity protection components.

[0013] Balloon longevity and durability are important to surgeons because if the treatment is not complete when the pulse limit is reached, the balloon must be removed, disconnected from the power source, and an entirely new disposable balloon inserted into the patient's vasculature to complete the treatment. This is undesirable for a variety of reasons, including time, expense, balloon localization / overlap, and further exposure of the patient to potential harm.

[0014] The exact mechanism of balloon failure in IVL devices is not widely understood. There are many theories and possible causes. Plasma spark energy, cavitation bubbles, and heat are known agents with highly destructive properties. Summary of the Invention

[0015] Without being bound by any one theory, the present invention addresses the possibility of malfunction due at least in part to electrical arcs and / or currents and / or plasma discharges between the IVL emitter and the deployed balloon, or the possibility of unwanted electrical discharges and / or electrical arcs and / or currents between the deployed balloon and tissue.

[0016] The present invention provides improved IVL systems and components with a reduced tendency to malfunction caused by unwanted electrical arcs and / or currents and / or plasma discharges between the IVL emitter and the deployed balloon. Additionally or alternatively, the present invention provides improved IVL systems and components with a reduced tendency to malfunction caused by the possibility of unwanted electrical discharges and / or electrical arcs and / or currents between the deployed balloon and tissue. This unwanted energy flow can occur during the delivery of the treatment, but can also occur during or at the end of a treatment pulse due to charging of the fluid solution within the balloon over time and its effects outside the balloon.

[0017] The disclosed invention addresses shortcomings in current intravascular lithotripsy systems by preventing or inhibiting the above-described undesired discharge of energy, which can cause accidental damage to the patient or the device itself, particularly the balloon. The invention is particularly desirable in cardiac applications, where the unintended discharge of electrical energy to the patient can impair or cause damage to the patient's cardiac cycle, conduction pathways, and / or ability to properly control the heart. The invention includes modifications to existing devices to insulate, isolate, or shield the balloon (e.g., by adding electrical insulation), thereby preventing or inhibiting the unwanted release of energy.

[0018] The various inventions disclosed herein address these problems, among others.

[0019] The following drawings are illustrative illustrations of certain embodiments and are therefore not intended to limit the disclosure. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram of a system for providing intravascular lithotripsy according to one aspect of the present invention. [Figure 2] FIG. 1 illustrates an inflated balloon within a blood vessel for providing intravascular lithotripsy according to one aspect of the present invention. [Figure 3] 1A-1C are diagrams of examples of balloon materials according to the present invention. [Figure 4] FIG. 2 is a diagram of a second example of a balloon material according to the present invention. [Figure 5] FIG. 2 is a diagram of a third example of a balloon material according to the present invention. [Figure 6] FIG. 10 is a diagram of a fourth example of a balloon material according to the present invention. [Figure 7] FIG. 10 is a schematic diagram of another embodiment of the present invention utilizing five electrode pairs. [Figure 8] FIG. 10 is a schematic diagram of another embodiment showing wiring of an electrode pair with at least one latching switch. [Figure 9]FIG. 1 illustrates features of a particular IVL catheter, detailing the effective length of the IVL catheter, the energy profile of the IVL catheter, and the provision of an optimized overlap zone within such an IVL catheter design. DETAILED DESCRIPTION OF THE INVENTION

[0021] Unless the context otherwise indicates, the following words or phrases shall have the following meanings (in both their singular and plural forms):

[0022] The words "insulator," "insulating," or "insulating" mean electrically insulating and refer to a dielectric material that allows little, if any, flow of electrical current through the material. Insulating materials may also be thermally insulating, but this is not necessarily the case. Materials such as glass, metal oxides, porcelain, paper, plastics, polymers, and rubber are representative of insulating materials.

[0023] The terms "conductor," "conductive," and "conducting" refer to electrically conductive materials that readily allow the flow of electric current through them. Conductive materials may, in some instances, also be thermally conductive, but this is not always the case. Materials such as carbon black, gold, and metals are exemplary conductive materials.

[0024] The phrase "conductive pathway" refers to a possible path for current flow along that pathway and may refer, for example, to the entire surface of a balloon on a component thereof coated with conductive material, or only a portion of the surface coated with conductive material, such as a conductive stripe or predetermined (e.g., rectangular) shape on a surface or layer of the balloon. The conductive pathway may be placed on the balloon's surface by known ink printing or other techniques. Examples of ink-printed medical devices are described in U.S. Patent Nos. 5,836,874, 7,379,767, 9,763,624, 9,913,594, and 10,751,000. In some cases, such conductive pathways may create a virtual or actual Faraday cage effect that blocks unwanted energy flow from the balloon to the patient.

[0025] The phrase "intravascular lithotripsy device" includes devices that generate acoustic waves by arcing between electrode components, but may also include devices that generate acoustic energy within a balloon via a laser energy source. Examples of such laser systems are described in U.S. Patent Nos. 11,058,492 and 11,246,569 (the entire contents of which are incorporated by reference). Examples of electrically guided systems are described in U.S. Patent Nos. 8,728,091, 9,642,673, and 10,850,078, and U.S. Patent Application Publication No. 2022-0054194 (the entire contents of which are incorporated by reference).

[0026] The term "lithotripsy emitter" refers to an electrode-based system and may also include laser or optical systems.

[0027] The phrase "high voltage pulse" means an electrical pulse with a minimum voltage of at least 2000 volts, and in some embodiments, a maximum voltage of at least 3000 volts.

[0028] The phrase "thin-wall balloon material" refers to any compliant, semi-compliant, or non-compliant balloon material having a thickness of less than about 0.0009 inches. Preferably, thin-wall balloon materials are made of materials that have a thickness of less than 0.0009 inches in an unstretched state before inflation. One such material includes polyamides with repeating units linked by amide bonds. Some nylon and PEBAX materials are suitable. Such materials may also include materials such as composite or multilayer structures. Compliant materials include silicone, polyurethane, or nitinol materials. In some embodiments, the thin-wall balloon material may comprise the balloon in a balloon design, where the fluid filling the inner balloon may be different from the fluid filling the outer balloon to take advantage of the insulating properties of the materials or the difference in the sound speed of the materials. Compliant, semi-compliant, and non-compliant materials may include nylon, polyurethane, silicone, polyethylene terephthalate (PET), and other biocompatible materials. In one embodiment, the burst pressure of the thin-walled balloon is typically between about 4 and 20 atmospheres, more preferably between 8 and 12 atmospheres, with one example being a nylon 12 material having a rated burst pressure between about 9 and 12 atmospheres.

[0029] The phrase "self-sealing material" refers to a flowable material that is capable of flowing into pinholes in the balloon caused by the operation of the system 10.

[0030] 1 and 2 show a system 10 according to the present invention, comprising a power source 12 (in the form of an electrical generator, but alternatively in the form of a laser system), a handle 14 with treatment delivery controls 15, a catheter 20 with two lithotripsy emitters 22 (shown in the form of a pair of arc electrodes, but alternatively may comprise optical or laser emitters), and a fluid-filled balloon 24. Optional marker bands B may be provided. The catheter 20 preferably includes a central tube 26 defining a guidewire lumen 27 through which a guidewire G passes for conveying the balloon 24 along the guidewire G to a desired location. A sheath 28 surrounds the central tube 26 and defines a delivery lumen 29 through which saline solution can be controllably delivered to inflate the balloon 24. Lumen 29 provides a concentric space around central tube 26 through which electrode wires (not shown) can extend from control unit 15 to emitter 22, among other components according to the present invention as described below. Sheath 28 is connected at its proximal end to hub 17, which may include any number of ports through which electrode wires can be threaded through lumen 29, along with saline for inflation, guidewire G, and any number of other components as required.

[0031] The balloon 24 may be placed in a deflated position so that it can more easily pass through the patient's vasculature to the site of calcification. In use, the balloon 24 is inflated to a pressure typical for angioplasty procedures (e.g., 4 atmospheres) and treatment is initiated via the delivery control device 15.

[0032] 2 shows the balloon 24 inflated to a treatment delivery state, where the lithotripsy emitter 24 may be "fired" to disrupt calcium C. An optional indicator band B may be provided to allow visualization and proper positioning using known imaging techniques. The balloon 24 is inflated to a typical angioplasty pressure (e.g., 4 atmospheres) and the treatment is delivered. The balloon 24 may naturally inflate during or immediately after the treatment to clear the vessel for blood to pass.

[0033] The material of the balloon 24 is inflated well below its burst pressure (e.g., 10 atmospheres) to avoid malfunction of the balloon. Figures 3-6 show different embodiments of balloon materials 300, 400, 500, and 600 according to the present invention.

[0034] Materials 300, 400, 500, and 600 should not impede the treatment from the lithotripsy emitter from reaching the calcium. For lithotripsy emitters that emit acoustic waves at the speed of sound, materials 300, 400, 500, and 600 should not excessively interfere with the acoustic energy delivered to the calcium. The speed of "acoustic waves" and wave propagation (called the speed of sound) is a material property of a medium. It is approximately 340 m / s in air and approximately 1500 m / s in water and most soft tissues in the body. The difference between the speed of sound of materials 300, 400, 500, and 600 and their thicknesses should not differ significantly from the wave speed in the fluid portion of the balloon or the surrounding soft tissues typically encountered. Typically, balloon materials result in balloon diameters between 1.5 mm and 6 mm, more preferably between 2 and 4 mm, and more preferably about 3.5 mm, at approximately 4 atmospheres. Other balloon sizes are within the scope of the present invention.

[0035] FIG. 3 shows one embodiment of material 300 for balloon 24, including a thin-walled polyamide with repeating units linked by amide bonds, such as nylon 310, with an optional hydrophilic coating to make the device more slippery. Material 310 may optionally contain a layer of self-sealing material 315, such as rubber (or other hemostatic material due to its proximity to blood), that can flow into pinholes that system 10 creates in the balloon during use. The self-sealing material may flow into pinholes to prevent leakage. Material 300 includes conductive material 320 to provide a path to ground to prevent harmful electrical flow from the balloon to tissue. Material 300 may allow the balloon 24 to have an external electrical potential that is less than the electrical potential of its internal components.

[0036] 4 shows one embodiment of material 400 of balloon 24, including conductive material 415 for providing an electrical path for current to ground and from tissue to comprise material 425, such as nylon. Conductive material 415 may include an outer hydrophilic coating to make material 400 slippery. Conductive material 415 inhibits harmful electrical flow from the balloon to tissue by providing such energy an alternate, safe path to ground. Material 400 may include optional self-sealing material 435 inside balloon material 400. Material 400 may optionally provide a balloon catheter with a greater electrical potential than the internal components of balloon 400.

[0037] In another embodiment, the balloon includes a conductive material on, above, or within the outer wall of the balloon. Materials and techniques commonly found in electroactive polymer constructions, utilizing high voltages within the anticipated range of use within IVL devices, can be used in this construction. The coating / implant should be selected to include conductivity and load capacity that allows partial to complete coupling and discharge of the energy delivered to / from the center of the balloon. The material should also be capable of charging to create a charge difference that resists the electrode's charging potential from reaching its surface.

[0038] 5 shows an alternative embodiment of material 500 of balloon 24 comprising conductive material 515 to provide an electrical path for current to ground and away from tissue. Material 400 may also include common angioplasty material 525, such as nylon. Conductive material 515 inhibits harmful electrical flow from the balloon to tissue by providing an alternate, safe path for such energy to ground.

[0039] Alternatively, the conductive path or material 415 or 515 may be used to charge the outer surface of the balloon to reduce the potential energy transferred from the inner lumen to the outside of the balloon. This charge may be sufficient for some flow to the tissue, but not enough to cause tissue damage. This helps mitigate the transfer of significant energy from the balloon 24 to the patient by reducing the charge potential between the emitter and the ground of the patient or balloon, making the ground of the catheter (the primary electrical circuit design path for current) the path of least resistance and increasing the impedance to the balloon or body.

[0040] 6 shows an alternative embodiment of a material 600 for balloon 24, comprising a material 625 such as nylon. Material 600 includes a conductive material 660 inside balloon 24 to provide a safe path for energy to flow to ground rather than from the balloon to the patient. Material 600 may allow for the balloon 24 to have an outside potential that is less than the potential of the inner components of balloon 24.

[0041] Commercially available IVL devices operate at slightly less than 3000 volts and contain currents of 20-300 amps. The present invention may allow for the use of higher voltages and / or currents or electricity while still safely protecting the patient.

[0042] 7 illustrates another embodiment of the present invention for an IVL system 700, which includes a fluid-fillable balloon B, a catheter (schematically shown as box C), five electrode pairs E1, E2, E3, E4, and E5, and a power and control source P for the electrode pairs. In this embodiment, the balloon B and catheter / delivery tube C are configured to serve as a primary or secondary ground / return path for energy from the power and control source P that is not partially or completely discharged / grounded to a return path within the balloon.

[0043] Figure 8 illustrates another embodiment of the present invention, for example, in a system with five electrode pairs E1-E5. System 800 includes at least one thermally activated latching switch L1, preferably located in the distal portion of the balloon's interior space. Latching switch L1 may be triggered with each activation via balloon / spark heat and / or may be generated only when the balloon or fluid therein heats above a safety threshold, at which point the console identifies and latches a signal, allowing the console to identify a "short circuit" within the balloon. Once a safe temperature is reached, the "circuit" becomes operational again. Various transistor technologies and / or the use of temperature-activated materials common in this space for activation and reactivation, such as Nitinol (NITI), may be useful in this field.

[0044] In other embodiments, the balloon may have a conductive cage, or even a single wire embedded in the inner lumen of the balloon, which expands to the diameter of the balloon using a very small conductor, which has limited effect on the profile and / or deliverability of the balloon and / or catheter.

[0045] For electrical insulation of 3000V (approximately IVL voltage), a balloon thickness of 0.005 inches or more is required when dry, i.e., more than five times thicker. Such materials have a dielectric strength of 600v / mil, which is the case for certain nylons that can be used in accordance with the present invention.

[0046] In one embodiment, a preferred balloon wall has a dielectric strength of 3333 V / mil for a wall thickness of 0.0009 inches. Such a preferred balloon combines potential energy and dielectric strength to reduce risk to the patient.

[0047] The dielectric properties of the material used to fabricate the balloon can also improve thin-walled balloons to prevent discharge through or by the balloon into the patient's body. It is understood that in prior art systems, balloons made of nylon (Grilamid and Pebax series) and similar materials with wall thicknesses as thin as 0.0009 can malfunction during use, and such malfunctions are believed to be at least partially due to electrical discharges or caused by undesired electrical arcs and / or currents and / or plasma discharges from the IVL emitter to the deployed balloon into the patient's tissues. Therefore, fabricating the balloon from a suitable flexible material with more favorable dielectric properties that are more electrically insulating than nylon can result in improved thin-walled balloons. Additional balloon material options for enhancing dielectric properties and dielectric strength include Mylar or Kapton, which have higher dielectric resistance. Higher dielectric strength means higher quality insulation.

[0048] The dielectric properties are measured by measuring the relative permittivity (ε r ) and relative permeability (μ r ) measurement. r Part of the determination of the dielectric constant (ε) is known as the permittivity, which is a measure of the amount of energy from an external electric field applied across a material that is stored in the material. r Another part of the dielectric constant is the loss factor, which is a measure of the energy loss from the material due to an external electric field. For nylon in an electric field at room temperature and a frequency of 2.45 GHz, the dielectric constant is 2.4 and the loss factor is 0.0083. Relative permeability is a similar concept to relative permittivity, except that the energy stored and dissipated is magnetic field energy rather than electric field energy. See the publication "Measurement of Dielectric Material Properties, Rohde & Schwarz, 04-2012 (hereinafter "R&S Publication"), the entire contents of which are incorporated herein by reference for all purposes. It is also understood that ASTM D149 can be used to determine dielectric strength.

[0049] Measurement of the dielectric constant includes several methods, including the transmission / reflection line method, the open-ended coaxial probe method, the free-space method, and the resonance method. Of these methods, the free-space method is particularly applicable to measuring the dielectric constant of materials that may be suitable for fabricating thin-walled balloons, because such materials can be provided as large, flat, solid objects for testing. It is contemplated that any of the other methods disclosed in U&S publications may be used, and the transmission / reflection line method is also well suited to small, solid objects.

[0050] Specifically, in the free-space method, the material under test is placed between two relatively large, flat antennas facing each other, which are connected to a network analyzer. S-parameters are measured by placing a holder midway between the two antennas, operating at a set frequency, then placing the material in the holder and measuring the S-parameters again. The effects of the sample holder are canceled so that the S-parameters of the material can be determined. The dielectric properties of the material can be determined by post-processing the measured reflection and transmission coefficients using known transform programming, which may be provided in the network analyzer or otherwise with any number of microprocessors, memory, and other computing hardware.

[0051] Such free-space testing can be performed first on a material such as nylon with a thickness of 0.0009 mm, followed by the same test on other materials of similar thickness. The dielectric properties of various materials can then be compared. Suitable inflatable balloon materials with superior dielectric properties compared to nylon, as described above, create improved balloons that are less likely to malfunction during use due, at least in part, to electrical discharge or unwanted electrical arcs and / or currents and / or plasma discharges from the IVL emitter to the deployed balloon and into the patient's tissue. Improved thin-walled balloons are less likely to malfunction or to cause electrical discharges or unwanted electrical arcs and / or currents and / or plasma discharges from the IVL emitter to the deployed balloon and into the patient's tissue.

[0052] In another aspect, the invention may include utilizing a martensitic band / electrode material to allow connection of material being corroded from the band and altering the conductive and ground path through magnetic means (used to collect such corroded material) to reduce uncontrolled variable conductivity of the solution / fluid around the electrode.

[0053] The description of the invention and its applications set forth herein is illustrative and is not intended to limit the scope of the invention. Features of various embodiments may be combined with other embodiments within the contemplation of the invention. Variations and modifications of the embodiments disclosed herein are possible, and practical substitutes and equivalents for the various elements of the embodiments will be apparent to those skilled in the art upon review of this patent document. These and other variations and modifications of the embodiments disclosed herein can be made without departing from the scope and spirit of the invention. [Explanation of symbols]

[0054] 10 Systems 12 Power supply 14 Handle 15 Control device 17 Hub 20 catheter 22 Emitter 24 Balloon 26 Central Tube 27, 29 lumen 28 Sheath B Marker band, balloon G Guidewire 300, 400, 500, 600 Balloon material 310 Material 315 Self-sealing materials 415 Conductive Materials 425 Material 435 Self-sealing materials 515 Conductive Materials 525 Angioplasty Materials 625 Material 660 Conductive Materials 700 IVL System 800 System E1, E2, E3, E4, E5 electrode pairs C Tube P Power supply / control source

Claims

1. 1. A catheter for an intravascular lithotripsy procedure, comprising: A long body that is small enough to fit inside a blood vessel, a guidewire lumen extending through the catheter; a thin-walled balloon located near the distal end of the elongate body, the distal and proximal ends of the balloon being sealed to allow inflation and deflation of the balloon with a fluid; at least two electrode pairs within the balloon capable of receiving a high voltage pulse and generating an arc within the fluid when the fluid inflates the thin-walled balloon, the catheter providing sufficient energy within the balloon to create a plasma arc within the fluid and initiate a shock wave within the balloon, the balloon material having a dielectric constant less than that of nylon and therefore more dielectric than nylon; A catheter comprising:

2. The catheter of claim 1 , wherein the balloon material also has a dielectric constant lower than that of nylon.

3. The catheter of claim 1 , wherein the balloon material has a higher dielectric strength than nylon.

4. The catheter of claim 2 , wherein the balloon material also has a loss factor that is lower than the loss factor of nylon.

5. 10. The catheter of claim 1, wherein the balloon material is 0.0009 inches or less thick.

6. The catheter of claim 1, wherein the balloon material has a burst strength of between about 4 and 20 atmospheres.

7. 10. The catheter of claim 1, wherein the thin-walled balloon is made of a material having a thickness of less than 0.0009 inches before inflation.

8. 1. A catheter for an intravascular lithotripsy procedure, comprising: A long body that is small enough to fit inside a blood vessel, a guidewire lumen extending through the catheter; a thin-walled balloon located near the distal end of the elongate body, the distal and proximal ends of the balloon being sealed to allow inflation and deflation of the balloon with a fluid; at least two electrode pairs within the balloon capable of receiving a high voltage pulse and generating an arc within the fluid when the fluid inflates the thin-walled balloon, the catheter providing sufficient energy within the balloon to create a plasma arc within the fluid and initiate a shock wave within the balloon, the balloon material having a thickness less than 0.0009 inches before inflation; A catheter comprising:

9. 9. The catheter of claim 8, wherein the thin-walled balloon has a dielectric constant at least equal to or less than that of a Grilamid or Pebax series nylon.

10. 9. The catheter of claim 8, wherein the thin-walled balloon has a dielectric constant that is the same as or lower than that of Grilamid or Pebax series nylons.

11. 9. The catheter of claim 8, wherein the balloon material has a dielectric strength equal to or greater than that of Grilamid or Pebax series nylons.

12. The catheter of claim 10, wherein the balloon material also has a loss factor equal to or less than that of nylon.

13. 1. A catheter for an intravascular lithotripsy procedure, comprising: A long body that is small enough to fit inside a blood vessel, a guidewire lumen extending through the catheter; a thin-walled balloon located near the distal end of the elongate body, the distal and proximal ends of the balloon being sealed to allow inflation and deflation of the balloon with a fluid; at least two electrode pairs within the balloon capable of receiving a high voltage pulse and generating an arc within the fluid when the fluid inflates the thin-walled balloon, the catheter providing sufficient energy within the balloon to create a plasma arc within the fluid and initiate a shock wave within the balloon, the balloon material having a dielectric constant less than that of nylon and therefore more dielectric than nylon, the balloon material having a thickness less than 0.0009 inches before inflation; A catheter comprising:

14. The catheter of claim 13, wherein the balloon material also has a dielectric constant lower than that of nylon.

15. The catheter of claim 13, wherein the balloon material has a higher dielectric strength than nylon.

16. 15. The catheter of claim 14, wherein the balloon material also has a loss factor that is lower than the loss factor of nylon.

17. 14. The catheter of claim 13, wherein the balloon material has a burst strength of between about 4 and 20 atmospheres.

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