Necessary voltage application duration for intravascular lithotripsy systems, devices and methods

Abstract

A system, device and / or method to execute intravascular lithotripsy procedures. Some embodiments comprise providing a maximum open gate duration for applying energy in the form of voltage pulses to spaced-apart electrodes that ensures that at least about 95% of the applied voltage pulses result in the generation of electrical arcs between the spaced-apart electrodes. Other embodiments may provide a maximum open gate duration that ensures that at least about 99% of the applied voltage pulses result in the generation of electrical arcs between the spaced-apart electrodes. Still other embodiments may provide a maximum open gate duration that ensures that about 100% of the applied voltage pulses result in the generation of electrical arcs between the spaced-apart electrodes.

Description

Attorney Docket 23812.7A / 15762WOO1NECESSARY VOLTAGE APPLICATION DURATION FOR INTRAVASCULAR LITHOTRIPSY SYSTEMS, DEVICES AND METHODSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to United States Provisional Patent Application Serial No. 63 / 696,61 1 filed on September 19, 2024 and entitled “Necessary Voltage Application Duration for Intravascular Lithotripsy Systems, Devices and Methods,” and which application is expressly incorporated herein by reference in its entirety.BACKGROUND

[0002] A variety of techniques and instruments have been developed for use in the removal or repair of tissue in arteries and similar body passageways, including removal and / or cracking of calcified lesions within the passageway and / or formed within thewa ll defining the passageway. Afrequent objective of such techniques and instruments is the removal of atherosclerotic plaque in a patient's arteries. Atherosclerosis is characterized by the buildup of fatty deposits (atheromas) in the intimal layer (i.e., under the endothelium) of a patient's blood vessels. Very often over time what initia Uy is deposited as relatively soft, cholesterol-rich atheromatous material hardens into a calcified atherosclerotic plaque, often within the vessel wall. Such atheromas restrict the flow of blood, cause the vessel to be less compliant than the same vessel absent atheromas, and therefore often are referred to as stenotic lesions or stenoses, the blocking material being referred to as stenotic material. If left untreated, such stenoses can cause angina, hypertension, myocardial infarction, strokes and the like.

[0003] Angioplasty, or balloon angioplasty, is an endovascularprocedure to treat by widening narrowed or obstructed arteries or veins, typically to treat arterial atherosclerosis. A collapsed balloon is typically passed through a pre-positioned catheter and over a guide wire into the narrowed occlusion and then inflated to a fixed pressure. The balloon forces expansion of the occlusion within the vessel and the surrounding muscular wall until the occlusion yields from the radialforce applied by the expanding balloon, opening up the blood vessel with an inner diameter that is similarto the native vessel in the occlusion area and, thereby, improvingblood flow.Attorney Docket 23812.7A / 15762WOO1

[0004] Balloon angioplasty can be enhanced by using intravascular lithotripsy (IVL). Generally, known IVL devices include a voltage pulse generator in operative communication with one or more pairs of electrodes mounted on a catheter and within an inflatable balloon of a catheter. The balloon is inflated using a conductive fluid. One or a series of high-voltage pulses can be applied to the pairs of electrodes causing arcing, resulting in pressure waves that travel from the pairs of electrodes, through the fluid, and to the lesions, helping to crack or break up the lesions to restore compliance.

[0005] Intravascular lithotripsy systems, devices and methods have been described by Applicant. See PCT / 2022 / 074607, filed by Applicant on August 5, 2022 and entitled “INTRAVASCULAR LITHOTRIPSY BALLOON SYSTEMS, DEVICES AND METHODS”, and PCT / US2023 / 085868, filed by Applicant on December 23, 2023 and entitled “INTRAVASCULAR LITHOTRIPSY SYSTEM WITH IMPROVED DURABILITY, EFFICIENCY AND PRESSURE OUTPUT VARIABILITY”, the entire contents of each of which are hereby incorporated by reference.

[0006] The high voltage pulses are generally provided by using a system that stores energy and releases the energy, by closing a switch to the pairs of electrodes from an energy storage. For example, the energy storage may be implemented using a bank of capacitors to store energy and then release the energy when a switch is closed. Two diametrically opposed issues arise from these types of configurations. First, if the switch is notclosed for a longenough period of time, an arc will notform. In particular, a voltage across the electrodes causes a breakdown in the medium between the electrodes which allows for the arc to occur. However, if the voltage is not high enough and / or is not applied fora sufficientamountof time, the break down will not occur and the arc will not be formed.

[0007] At the opposite end of the spectrum, if the switch is closed longer than necessary, current will flow between the electrodes, even if no arc is formed. This can result in degradation of the electrodes, heating of the conductive fluid, energy loss, and have other deleterious effects.

[0008] The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate oneAttorney Docket 23812.7A / 15762WOO1 exemplary technology area where some embodiments described herein may be practiced.BRIEFSUMMARY

[0009]

[0010] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essentia I features of the claimed subject matter, nor is it intended to be used as an aid in determiningthe scope of the claimed subject matter.

[0011] Additional features and advantages will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the teachings herein. Features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. Features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as setforth hereinafter.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to describe the manner in which the above-recited and other advantages and features can be obtained, a more particular description of the subject matter briefly described above will be rendered by reference to specific embodiments which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments and are not therefore to be considered to be limiting in scope, embodiments will be described and explained with additionalspecificity and detail through the use of the accompanyingdrawings in which:

[0013] FIGURE 1 illustrates a schematic view of an IVL system.

[0014] FIGURE 2 illustrates a schematic view of part of an IVL system.

[0015] FIGURE 3 illustrates a graphic illustration of a timing of applied voltage and current during application of voltage and generation of an electrical arc between spaced-apart electrodes.

[0016] FIGURE 4 illustrates an exemplary arcing waveform for one embodiment of the current disclosure.Attorney Docket 23812.7A / 15762WOO1

[0017] FIGURE 5 illustrates a histogram of voltage on time measurements.

[0018] FIGURE 6A illustrates an exemplary voltage and current measurement and time delta indicating a successfully generated electrical arc and duration of voltage application to spaced-apart electrodes for one embodiment of the current disclosure.

[0019] FIGURE 6B illustrates an exemplary power measurement during application of voltage to spaced-apart electrodes for an embodiment of the current disclosure.DETAILED DESCRIPTION

[0020] As illustrated in Figure 1 , a diagrammaticorschematic layout of portions of an exemplary IVL system 1 10 is provided. The illustrative IVL system 110 comprises a catheter assembly 1 14 including an elongate body, embodied as a catheter having guidewire 1 15, and a fluid-filled member 1 16 configured to contain conductive fluid therein, exemplified by an inflatable balloon, disposed near the distal end of the elongate body and arranged to receive fluid for inflation to facilitate IVL therapy. A set of dischargeable spaced a part electrodes 1 18 are shown arranged within the exemplary fluid-filled member 1 16, at least some of which are spaced a part by a gap 1 17 from each other to create a spark or electrical arc between the set of spaced-apart electrodes 1 18.

[0021] The IVL system embodiments described herein may be used in connection with electrodes that are within a fluid-filled member 1 16 configured to contain a fluid, e.g., a conductive fluid, therein. The fluid-filled member 116 embodiments may include an inflatable balloon or enclosure as shown in Figure 1, which may be compliant or non-compliant and serves to contain the fluid such that the spaced-apart electrodes 1 18 are, in some embodiments, fully submerged within the contained fluid. In addition, the fluid-filled member 1 16 may comprise a fillable member that is at least partially rigid and / or not flexible. In other embodiments, the fluid-filled member 1 16 may contain the fluid therein and wherein the set of spaced apart electrodes 1 18 are, in some embodiments, fully submerged within the contained fluid during generation of an electrical arc between the spaced-apart electrodes during an IVL procedure.Attorney Docket 23812.7A / 15762WOO1

[0022] Alternatively, the IVL system control embodiments of the present disclosure may be used in connection with electrodes that are not located or surrounded by a fluid-filled or fillable member 1 16. In these embodiments, the IVL system maycomprise one or more sets of spaced- a part electrodes 1 18thatmay be continuously or periodically exposed to saline or other fluid and, during the exposure, the IVL system may generate an electrical arc between the spaced-apart electrodes 1 18.

[0023] Each of the spaced-apart electrodes in Figure 1 is arranged in communication (as suggested by dashed line conductors) with an electric pulse generation system, or voltage pulse generator 120 to receive high voltage electrica I energy for spark generation to create pressure waves for IVL therapy. In the illustrative embodiment, one electrode may be grounded and the other provided with high voltage from the voltage pulse generator 120, although in some embodiments, any voltage differential may be applied. The voltage pulse generator 120 may include a capacitor bank 121 , an IVL control system 122 comprising a processor 124 configured for executing instructions stored on memory 126 and communications signals via circuitry 128 for IVL operations according to the processor governance. The capacitor bank 121 , processor 124, memory 126, and circuitry 128 may be arranged in communication with each other (as suggested via dashed lines) to facilitate disclosed operations. The capacitor bank 121 may store and be selectively connected through a gate 129 to trigger a release of available stored energy to the spaced apart electrodes 1 18 generate electrical arcs. In particular, the gate 129 may be a switch, such as a IGBT, spark gap switch, or other high voltage capable switch. An open gate is a gate that has been placed in configuration to deliver energy from the capacitor bank 121 to the spaced apart electrodes 1 18. That is, an open gate condition selectively connects the capacitor bank 121 (or other energy storage device) to the spaced apart electrodes 1 18 to complete a circuit for delivering a voltage pulse to the spaced apart electrodes. 1 18.

[0024] An exemplary IVL system is shown in Figure 2, illustrating one method for applying voltage pulses to the system, resulting in current flow through the exemplary system to each set of spaced-apart electrodes 1 18, where each set of spaced-apart electrodes 1 18 forms a spark gap 1 17. In the illustrated example, twoAttorney Docket 23812.7A / 15762WOO1 sets of spaced a part electrodes form an emitter 1 19. Agiven emitter 1 19 mayinclude two spark gaps so as to accomplish more complete energy coverage, such as when the spark gaps are located on conductive bands around a catheter lumen to allow for pressure waves in multiple directions. Note that in other embodiments, emitters may include a single spark gap or more than two spark gaps. The emitters 1 19, and thus the four sets of spaced-apart electrodes (and thus spark gaps 1 17) are connected in series. Figure 2 illustrates two emitters 1 19 defined within a support body. Application of a voltage pulse of sufficient magnitude and / or duration from the voltage pulse generator 120 to the sets of serially connected spark gaps 1 17 will result in a production of electrical arcs asfollows: a first arc across a first sparkgap; a second arc across a second spark gap, a third arc across a third spark gap and a fourth arc across a fourth spark gap.

[0025] Appropriate control of such high-energy systems can also require achievingsufficient energy atthe discharge site to create an electrical arc across the one or more spark gaps of an IVL system. Embodiments of the IVL systems, devices and methods described within the present disclosure may include operation for adjusting the total electrical energy provided to the system at each emitter. Such control systems for intravascular lithotripsy systems, devices and methods have been described by Applicant. See PCT / 2023 / 079209, filed byApplicanton November9, 2023 and entitled “CONTROL OF IVL SYSTEMS, DEVICES AND METHODS THEREOF”; US 18 / 290173, filed by Applicant on November 10, 2023 and entitled “CONTROL OF IVL SYSTEMS, DEVICES AND METHODS THEREOF”; US 18 / 506339, filed by Applicant on November 10, 2023 and entitled “CONTROL OF IVL SYSTEMS, DEVICES AND METHODSTHEREOF”; US 18 / 506416, filed by Applicant on November10, 2023 and entitled “CONTROL OF IVL SYSTEMS, DEVICES AND METHODS THEREOF”; and US 18 / 506428, filed by Applicant on November 10, 2023 and entitled “CONTROL OF IVL SYSTEMS, DEVICES AND METHODS THEREOF”, the entire contents of which are hereby incorporated by reference. The voltage pulse may be generated by discharging energy stored in the voltage pulse generator 120, and in particular, in some embodiments, discharging energy stored in the capacitor bank 121 (Figure 1 ) which may produce an electrical arc across a spark gap between two spaced-apart electrodes. In some embodiments, the voltage pulses may beAttorney Docket 23812.7A / 15762WOO1 generated in one or more series of voltage pulses, wherein each adjacent series of voltage pulses may be spaced-apart or separated by time or other mechanism.

[0026] Figure 3 graphically illustrates the drop in impedance of a current leader across a spark in an IVL system such as shown in Figures 1 and / or 2 following application of a single voltage pulse to one of two spaced-apart electrodes as the current leader develops into an electrical arc between the spaced-apart electrodes. This, in turn, causes the power dissipated in the electrical arc to peak sharply while the voltage and current between the electrodes are both relatively high. The current reaches a peak and the voltage drops, both very rapidly, indicatingthat an electrica l arc between the spaced-apart electrodes is present, or has occurred. The peak of the power dissipated in the electrical arc indicates the relatively short time interval during which all the useful work of heating the growing leader into an arc is performed. The graphic illustration of Figure 3 is exemplary of one aspect of an IVL procedure that is configured to produce or generate pressure waves.

[0027] As noted previously, IVL systems and devices mayinclude a voltage pulse generator 120, including potentially the capacitor bank 121 which is triggered to release energy to generate electrical arcs. Following production of a series of voltage pulses, each of which is designed to generate an electrical arc as described above, the capacitor bank may retain residual energy in the form of voltage which may present a risk to the user / operator and / orthe patient.

[0028] Further, IVL procedures result in degradation of the spaced-apart electrodes 1 18 during the electrical arcing process. In addition, the conductivity of the surrounding fluid within the balloon or enclosure may be affected by the procession of electrical arcs generated during an IVL procedure, for example, due to gas bubbles and / or contaminants beingform ed in thefluid.

[0029] Moreover, gas generation is an issue with IVL systems and devices that make use of an enclosure such as an exemplary balloon and one or more sets of spaced-apart electrodes defining a spark gap, or emitters, surrounded by a conductive fluid held within the enclosure. Gas is generated as the fluid within the enclosure is vaporized during each electrical arc event and may accumulate following a series of voltage pulses, wherein each voltage pulse generates an electrical arc event. In someembodiments, each voltage pulse in a series of voltageAttorney Docket 23812.7A / 15762WOO1 pulses may be consecutive and may be produced in succession. The gas buildup within the balloon or enclosure is undesirable as it may, among other things, attenuate the pressure pulse or wave generated by the spaced-apart electrodes or emitters before the energy strikes a target treatment site, e.g., an occlusion and / or calcification within a blood vessel’s wall. Further, the gas buildup may degrade the efficiency of formation of the electrical arc or spark across the spark gap of the spaced-apart electrodes or emitters. Systems, Devices and Methods for detection of gas buildup have been described in US application 63 / 642,019 filed by Applicant on May3, 2024 and entitled SYSTEMS, DEVICESAND METHODS FOR DETECTION OF IVL GAS BUILDUP, the entire contents of which are hereby incorporated by reference.

[0030] A maximum duration of voltage application to an IVL system’s spaced- apart electrodes that is less than 40 microseconds and which provides very high confidence thatthe applied voltage will produce an electrical arc over one or more series of voltage pulses is provided. In some embodiments, the maximum duration of voltage application to the spaced-apart electrodes may be much less than 40 microseconds as will be described below. The duration of voltage application is the effective amount of time that a selected voltage magnitude is applied to a first electrode in a spaced-apart electrode pair and results in the generation of an electrical arc between the two spaced-apart electrodes.

[0031] As discussed above, it is highly advantageous to minimizethe duration of voltage application to the spaced-apart electrodes while maintaining a high confidence thatthe resultant application of voltage will result in an electrical arc for each generated and applied voltage pulse. In some embodiments, the IVL system may be configured to produce a number voltage pulses using a single catheter and related inflatablemember or balloon. In other embodiments, the IVL system maybe configured to produce in certain embodiments 1 -50 voltage pulses, 1 -100 voltage pulses, 1 -150 voltage pulses, 1 -200 voltage pulses, 1 -250 voltage pulses, 1 -300 voltage pulses, and / or more than 300 voltage pulses.

[0032] In some embodiments discussed herein, the IVL system may be configured to generate a voltage pulse resulting in an electrical arc between the spaced-apart electrodes where the voltage pulse may comprise an applied voltageAttorney Docket 23812.7A / 15762WOO1 magnitude between about 2000V and about 4000V. In some embodiments, an applied voltage magnitude may be between about 2850V and about 3650V.

[0033] Figure4 illustrates an exemplary arcing voltage waveform generated by an exemplary IVL system as described herein, with applied voltage of approximately 3250V across the spark gaps 1 17 and a time duration of voltage application to spaced-apart electrodes 1 18 of approximately 7 microseconds.

[0034] As shown in Figure 1 and with continued reference to Figure 2, the exemplary IVL system 1 10 is provided comprising an EPROM 134, which is discussed further below. The EPROM 134 is in operative communication and association with the processor 124, which is in the illustrated embodiment part of the voltage pulse generator 120. In other embodiments, the IVL control system 122, and associated processor 124, memory 126 and related circuitry 128 may be in operative and electrical communication with the voltage pulse generator 120, but located in a different physical location than the voltage pulse generator 120. The EPROM 134 is illustrated as located within or in operative association with the handle 136 of a catheter 138, which is in operative association with the fluid-filled member 1 16.

[0035] The processor 124 is in operative and / or electrical association with a voltage monitor 130 that is illustrated as located outside the voltage pulse generator 120. In some embodiments, the voltage monitor may be located in a separate location apart from the voltage pulse generator 120. In other embodiments, the voltage monitor 130 and / or current monitor 132 may be within the voltage pulse generator 120. The voltage pulse generator 120 may be in operative and electrica l association with one or more sets of spaced-apart electrodes 1 18. As illustrated, the various spaced-apart electrodes are connected in a serial electrical connection with the voltage pulse generator 120 operatively and / or electrically connected with a more proximally located emitter 1 19. Alternative connection associations between the set(s) of spaced-apart electrodes 1 18 or emitter(s) 1 19 and the voltage pulse generator 120 may be provided in alternative embodiments. For example, the two sets of spaced-apart electrodes may be connected in a parallel arrangement if implemented with separate powersupplies. Further, the voltage pulsegenerator 120 may be operatively and / or electrically associated with a more distal spaced-apart set of electrode 1 18 or emitter 1 19. In addition, a voltage monitor 130 and / or aAttorney Docket 23812.7A / 15762WOO1 current monitor 132 may be provided in operative connection and communication with the IVL control system 122 and / or the voltage pulse generator 120. Finally, a display may be operatively and / or electrically associated with the IVL control system 122.

[0036] Some embodiments may comprise a predetermined minimum time parameter and / or maximum parameters for the duration of an open gate condition within the voltage pulse generator 120 to ensure successfully generated electrica l arcs, i.e., generation and application of voltage pulses that result in an electrical arc between the spaced-apart electrodes, and a threshold parameter minimum voltage dissipation threshold which may comprise a voltage magnitude or a voltage dissipation rate. These predetermined open gate condition parameter(s) may be programmed into the EPROM (erasable programmable read-only memory) 134. In some embodiments, the EPROM 134 may be disposed within a handle 136 of the catheter 138. This arrangement in some embodiments allows the predetermined minimum and / or maximum open gate condition duration and voltage parameters to be programmed specifically to a certain model and / or device and / or system and / or catheter. Alternatively, the predetermined parameters andthreshold maybe stored within the memory 126 and / or processor 124.

[0037] Consequently, certainty of production of an effective, electrical arcgenerating voltage pulse may rely on generation of a predetermined voltage magnitude and application of the predetermined voltage magnitudeto the spaced- apart electrodes for a specified open gate condition duration. These parameters may be programmed into the EPROM 134 or, as discussed above, stored within the memory 126 and / or processor 124 of the IVL systeml 22. It is important to note that the duration of a voltage pulse that is limited by a predetermined maximum open gate condition influences or impacts the duration of application of voltage to the spaced-apart electrodes as a maximum durational value. That is, in almost all cases, a voltage pulse producing an electrical arc will comprise a duration that is less than the maximum threshold gate open condition duration. This is because, as will be discussed below, voltage rises following initiation of the voltage application by actuatingthe initial open gate condition. The stored voltage is then discharged, and dissipated, quickly over time and, as noted, in most cases all possible energy / Attorney Docket 23812.7A / 15762WOO1 voltage will be expended before the maximum open gate condition duration has been reached.

[0038] In some embodiments, the voltage application duration maximum threshold may be fixed by setting the open gate condition to a predetermined threshold or maximum duration. The actual voltage application duration, or “on time” voltage required to generate an electrical arc may be shorter than the predetermined maximum open gate condition duration. As a result, the predetermined maximum open gate condition duration parameter may be set at a selected, maximum duration to provide a desired confidence level in generating successful electrical arcs. These concepts will be discussed further below in the context of a Working Example.

[0039] WORKING EXAMPLE 1 - Voltage On Time

[0040] IVL systems of the current disclosure were tested to ascertain the actual required or necessary application duration for voltage to spaced-apart electrodes in order to generate an electrical arc. The IVL systems tested included catheters sized at 2.5x12 mm and 4.0x20 mm. The IVL systems generated voltage magnitudes that ranged from 2850V to 3650V, with incremental voltage magnitudes of 3250V and 3500V, resulting in a total number of generated voltage pulses of 2400.

[0041] WORKING EXAMPLE 1 - Voltage On Time Test Results

[0042] Figure 5 illustrates the results using a histogram of voltage on time, indicative of an applied voltage pulse resulting in an electrical arc. The “voltage on time” durational data on the x-axis is the measured duration of actual application, or discharge, of voltage to the spaced-apart electrodes. As also discussed above, the voltage on time measurement may be shorter than the setting of the open gate condition parameter. Accordingly, setting the open gate duration parameter at an appropriate threshold duration will ensure the desired confidence level in generating electrical arcs.

[0043] Across 2,400 voltage pulses, each of which resulted in a successful electrical arc, the following summary data apply to Working Example 1 :

[0044] The mean voltage on time, or voltage application duration, measured at approximately 10 microseconds (actual is 10.015 microseconds).

[0045] The standard deviation (“1 SD”) forthe data set is 1 .355.Attorney Docket 23812.7A / 15762WOO1

[0046] The rangeof successful duration of voltageon time, orvoltage application duration, measured at4.760 microseconds to 15.164 microseconds.

[0047] Using the mean voltage on time value, and the 1 SD value, a 95% confidence distribution of voltage on time, or voltage application durations, ranges from about 7 microseconds to a maximum of about 13 microseconds.

[0048] Further, a 99% confidence distribution of voltage on time, or voltage application durations, rangingfrom about 6 microseconds to a maximum of about 14 microseconds.

[0049] Still further, a 100% confidence distribution of voltage on time, or voltage application durations, rangingfrom about 5 microseconds to a maximum of about 15.5 microseconds.

[0050] WORKING EXAMPLE 1 - Voltage On Time Analysis

[0051] As noted, Working Example 1 tested generation of N = 2400 electrical arcs using embodiments of the disclosed IVL systems and methods, and that were produced from applied voltage magnitudes within a range of about 2850V to about 3650Vand measured the actual duration of voltage application required to generate the individual electrical arcs. The IVL systems tested included catheters sized at 2.5x12 mm and 4.0x20 mm.

[0052] The measurement of actual duration of voltage application was achieved via a high-voltage probe positioned across the discharging point in the voltage pulse generator, at a location that is just proximal to the catheter. The actual duration is measured as the point at which the voltage curve starts to rise and until the point that the voltage curve has dropped to a point that is slightly above its baseline level which maybe predetermined. In some embodiments, the baseline voltage level may comprise 0-100V, 0-200V, 0-300V, 0-400V, 0-500V, 0-600V, 0-700V, 0-800V, 0- 1000V, 0-1 100V, or other voltage level so long as the baseline voltage level is not higher than any artifact voltage downward spikes occurring as the voltage drops duringthe electrical arc generation. Thecurrent was also measured usinga Pearson 41 1 probe on one of the discharging wires leading from the voltage pulse generator to the spaced-apart electrodes, the probe placed on the output of the voltage pulse generator / input of the catheter or handle to measure the current magnitude during the voltage pulse application.Attorney Docket 23812.7A / 15762WOO1

[0053] An exemplary voltage curve, and associated current curve, is illustrated in Figure 6A. There, as voltage of a predetermined magnitude is released, e.g., from a capacitor bank, and applied to the spaced-apart electrodes, a spike in voltage is measured, up to approximately 3500Vin the exemplary voltage curve, though other peak values are within the scope of the invention as the skilled artisan will recognize. As the release of voltage progresses, the voltage curve slightly slopes in a downward direction. At approximately 8.1 microseconds in the example, the voltage drops suddenly and the associated current curve rises, a condition indicative of a generated electrical arc between the spaced-apart electrodes.

[0054] Viewed differently, as in Figure 6B, the data from Fig. 6A is shown in a power (kW) curve. The power curve’s magnitude rises, peaks and falls generally concurrently with the rise, peak and fall of the current curve, though the power curve’s peak occurs slightly earlier in time than the peak of the current curve.

[0055] The maximum actual applied voltage application duration was measured at approximately 15 microseconds which resulted in 100% of the applied voltage pulses generating electrical arcs. As a result, setting the open gate duration condition within the controller or EPROM as discussed above to 15 microseconds, or slightly greater than 15 microseconds to, e.g., 16 microseconds, or in other nonlimiting embodiments to less than 40 microseconds, may ensure that a successful electrical arc will be generated approximately 100% of the time using a single IVL device.

[0056] A safety measure may be added in some embodiments to further ensure thatsuccessful electrical arcs are generated under various conditions. Adding some additional safety duration for applied voltage to the spaced-apart electrodes may allow the IVL system to generate more pulses, e.g., more than 200 or 300 voltage pulses.

[0057] Based on these measured voltage application duration, or voltage on time, data, exemplary maximum open gate duration conditions may be set to provide a desired confidence distribution of successfully generated electrical arcs as follows:

[0058] 1 . In some embodiments, the open gate duration condition may be set at a maximum of 13 microseconds.Attorney Docket 23812.7A / 15762WOO1

[0059] 2. In some embodiments, the open gate duration condition may be set at a maximum of 14 microseconds.

[0060] 3. In some embodiments, the open gate duration condition may be set at a maximum of 15.5 microseconds.

[0061] The above exemplary open gate duration condition settings are based on the measured voltage application data and correspond to the upper range of the 95%, 99% and 100% confidence distributions, respectively. There is no safety measure added to the settings. Adding exemplary safety measures to the open gate duration condition setting may include the following ranges of maximum open gate duration conditions, without limitation:

[0062] 1 . In some embodiments, the maximum open gate condition duration may be set within a range of about 13 microseconds to about 14 microseconds.

[0063] 2. In some embodiments, the maximum open gate condition duration may be set within a range of about 13 microseconds to about 15 microseconds.

[0064] 3. In some embodiments, the maximum open gate condition duration may be set within a range of about 13 microseconds to about 16 microseconds.

[0065] 4. In some embodiments, the maximum open gate condition duration may be set within a range of about 13 microseconds to about 20 microseconds.

[0066] 5. In some embodiments, the maximum open gate condition duration may be set within a range of about 13 microseconds to about 25 microseconds.

[0067] 6. In some embodiments, the maximum open gate condition duration may be set within a range of about 13 microseconds to about 30 microseconds.

[0068] 7. In some embodiments, the maximum open gate condition duration may be set within a range of about 13 microseconds to about 35 microseconds.

[0069] 8. In some embodiments, the maximum open gate condition duration may be set within a range of about 13 microseconds to less than about 40 microseconds.

[0070] 9. In some embodiments, the maximum open gate condition duration may be set within a range of about 14 microseconds to about 15 microseconds.

[0071] 10. In some embodiments, the maximum open gate condition duration may be set within a range of about 14 microseconds to about 16 microseconds.

[0072] 1 1 . In some embodiments, the maximum open gate condition duration may be set within a range of about 14 microseconds to about 20 microseconds.Attorney Docket 23812.7A / 15762WOO1

[0073] 12. In some embodiments, the maximum open gate condition duration may be set within a range of about 14 microseconds to about 25 microseconds.

[0074] 13. In some embodiments, the maximum open gate condition duration may be set within a range of about 14 microseconds to about 30 microseconds.

[0075] 14. In some embodiments, the maximum open gate condition duration may be set within a range of about 14 microseconds to about 35 microseconds.

[0076] 15. In some embodiments, the maximum open gate condition duration may be set within a range of about 14 microseconds to less than about 40 microseconds.

[0077] 16. In some embodiments, the maximum open gate condition duration may be set within a range of about 15 microseconds to about 16 microseconds.

[0078] 17. In some embodiments, the maximum open gate condition duration may be set within a range of about 15 microseconds to about 20 microseconds.

[0079] 18. In some embodiments, the maximum open gate condition duration may be set within a range of about 15 microseconds to about 25 microseconds.

[0080] 19. In some embodiments, the maximum open gate condition duration may be set within a range of about 15 microseconds to about 30 microseconds.

[0081] 20. In some embodiments, the maximum open gate condition duration may be set within a range of about 15 microseconds to about 35 microseconds.

[0082] 21 . In some embodiments, the maximum open gate condition duration may be set within a range of about 15 microseconds to less than about 40 microseconds.

[0083] 22. In some embodiments, the maximum open gate condition duration may be set within a range of about 15.5 microseconds to about 16 microseconds.

[0084] 23. In some embodiments, the maximum open gate condition duration may be set within a range of about 15.5 microseconds to about 20 microseconds.

[0085] 24. In some embodiments, the maximum open gate condition duration may be set within a range of about 15.5 microseconds to about 25 microseconds.

[0086] 25. In some embodiments, the maximum open gate condition duration may be set within a range of about 15.5 microseconds to about 30 microseconds.

[0087] 26. In some embodiments, the maximum open gate condition duration may be set within a range of about 15.5 microseconds to about 35 microseconds.Attorney Docket 23812.7A / 15762WOO1

[0088] 1. In some embodiments, the maximum open gate condition duration may be set within a range of about 15.5 microseconds to less than about 40 microseconds.

[0089] WORKING EXAMPLE 2 - Effects of Contrast Media On Arc Generation

[0090] In a separate test, testing was conducted to determine the effects, if any, of different types of contrast media on electrical arc formation. The IVL systems tested included catheters sized at 2.5x12 mm and 4.0x20 mm. Three different commercially available contrast media were tested including VisipaqueTM, Isovue® and OmnipaqueTM, each formulated in a 50 / 50 mixture with saline. In addition, open gate duration conditions were tested across the contrast media, including 10, 12, 14, 16, 18, 20, 30 and 40 microseconds. The skilled artisan will appreciate that these data are tied to the specific open gate duration, and not to the actual duration of voltage application resulting in an electrical arc.

[0091] No significant differences in Working Example 2 test results were noted across the several types of contrast media, catheter sizes regarding necessary open gate condition durations. The data indicated some voltage pulses were insufficient to generate successful electrical arcs at 10, 12 and 14 microseconds, though the number of voltage pulses that did not result in successful electrical arcs decreased from 10 to 12 to 14 microseconds. The 14 microsecond duration resulted in nearly all voltage pulses generating electrical arcs which corresponds with the Working Example 1 data.

[0092] Clause 1. An intravascular lithotripsy ("IVL") system with improved efficiency, comprising: an elongate member; a fluid-fillable enclosure formed of a material and surrounding a distal region of the elongate member; at least one pair of spaced-apart electrodes operatively associated with the elongate member and within the fluid-fillable enclosure, wherein each pair of the at least one pair of spaced-apart electrodes form a spark gap; a fluid reservoir comprisinga fluid and in operative fluid communication and association with an interior of the fluid-fillable enclosure, a voltage pulse generator comprising a capacitor bank and in operative electrical communication and association with the at least one pair of spaced-apart electrodes, the capacitor bank configured to store energy; and a controller in operative association with thevoltage pulse generator and configured to control theAttorney Docket 23812.7A / 15762WOO1 voltage pulse generator to release at least some of the stored energy from the capacitor bank and apply the released energy to the spaced-apart electrodes, wherein the IVL system comprises a predetermined open gate duration that sets a predetermined maximum duration for application of energy to the spaced-apart electrodes, and wherein the predetermined maximum duration is less than 40 microseconds.

[0093] Clause 2. The IVL system of clause 1 , further comprising an EPROM in operative association and communication with the controller, wherein the EPROM stores the predetermined open gate duration.

[0094] Clause 3. The IVL system of one or both of clauses 1 and 2, wherein the predetermined maximum duration is within the group consisting of one or more of about 13 microseconds, about 14 microseconds, about 15 microseconds, about 15.5 microseconds, about 20 microseconds, about 25 microseconds, about 30 microseconds, and about 35 microseconds.

[0095] Clause 4. The IVL system of one or both of clauses 1 and 2, wherein the predetermined maximum duration provides at least about a 95% confidence distribution of successfully generated electrical arcs.

[0096] Clause 5. The IVL system of clause 4, wherein the predetermined maximum duration comprises at least 13 microseconds.

[0097] Clause 6. The IVL system of one or both of clauses 1 -2, wherein the predetermined maximum duration comprises a safety measure comprisinga longer duration.

[0098] Clause 7. The IVL system of clause 6, wherein the safety measure comprising a longer duration results in a predetermined open gate condition that is within the group consisting of one or more of about 15 microseconds, about 15.5 microseconds, about 20 microseconds, about 25 microseconds, about 30 microseconds, and about 35 microseconds.

[0099] Clause 8. The IVL system of one or both of clauses 1 and 2, wherein the predetermined maximum duration provides at least about a 99% confidence distribution of successfully generated electrical arcs.

[0100] Clause 9. The IVL system of clause 8, wherein the predetermined maximum duration comprises at least 14 microseconds.Attorney Docket 23812.7A / 15762WOO1

[0101] Clause 10. The IVL system of clause 9, wherein the safety measure comprising a longer duration results in a predetermined open gate condition that is within the group consisting of one or more of about 15 microseconds, about 15.5 microseconds, about 20 microseconds, about 25 microseconds, about 30 microseconds, and about 35 microseconds.

[0102] Clause 1 1 .The IVL system of one or both of clauses 1 and 2, wherein the predetermined maximum duration provides a bout a 100% confidence distribution of successfully generated electrical arcs.

[0103] Clause 12. The IVL system of clause 1 1 , wherein the predetermined maximum duration comprises at least 15.5 microseconds.

[0104] Clause 13. The IVL system of clause 12, wherein the predetermined maximum duration comprises a safety measure comprising a longer duration.

[0105] Clause 14. The IVL system of clause 14, wherein the safety measure comprising a longer duration results in a predetermined open gate condition that is within the group consisting of one or more of about 20 microseconds, about 25 microseconds, about 30 microseconds, and about 35 microseconds.

[0106] Clause 15. The IVL system of one or more of clauses 1 -14, wherein the IVL system is configured to generate a number of voltage pulses, wherein the number of generated voltage pulses is within the group consisting of one or more of 1 -50 voltage pulses, 1 -100 voltage pulses, 1 -200 voltage pulses, 1 -300 voltage pulses, and more than 300 voltage pulses.

[0107] Clause 16. The IVL system of one or more of clauses 1 -15, wherein an actual duration of voltage required to generate an electrical arc is less than the predetermined maximum duration.

[0108] Clause 17. A method for ensuring generation of electrical arcs in an intravascular lithotripsy ("IVL") system, comprising: providing an IVL system according to one or more of clauses 1 -16; initiating storage of energy within the capacitor bank; instructing with the controller, generation of a plurality of voltage pulses, each generated voltage pulse comprising a release of the stored energy from the capacitor bank; applyingeach oneof the generated voltage pulses in the plurality of voltage pulses to the spaced-apart electrodes, wherein the applying of each one of the plurality of voltage pulses comprises a duration that ensures that at leastAttorney Docket 23812.7A / 15762WOO1 about 95% of the applied voltage pulses in the plurality of voltage pulses generates an electrical arc between the spaced-apart electrodes.

[0109] Clause 18. The method of clause 17, wherein the applying of each one of the plurality of voltage pulses comprises a duration that ensures that at least about 99% of the applied voltage pulses in the plurality of voltage pulses generates an electrical arc between the spaced-apart electrodes.

[0110] Clause 19. The method of clause 17, wherein the applying of each one of the plurality of voltage pulses comprises a duration that ensures that about 100% of the applied voltage pulses in the plurality of voltage pulses generates an electrica l arc between the spaced-apart electrodes.

[0111] Clause 20. An IVL catheter system, device and method as shown and described.

[0112] The discussion refers to a number of methods and method acts that may be performed. Although the method acts may be discussed in a certain order or illustrated in a flow chart as occurring in a particular order, no particular ordering is required unless specifically stated, or required because an act is dependent on anotheract being completed priorto the act being performed.

[0113] The description of the invention and its applications as set forth herein is illustrative and is not intended to limitthe scope of the invention. Features of various embodiments may be combined with other embodiments within the contemplation of this invention. Variations and modifications of the embodiments disclosed herein are possible, and practical alternatives to and equivalents of the various elements of the embodiments would be understood to those of ordinary skill in the art upon study of this patent document. These and other variations and modifications of the embodiments disclosed herein maybe made without departingfrom the scope and spirit of the invention.

[0114] Further, the methods may be practiced by a computer system including one or more processors and computer-readable media such as computer memory. In particular, the computer memory may store computer-executable instructions that when executed by one or more processors cause various functions to be performed, such as the acts recited in the embodiments.Attorney Docket 23812.7A / 15762WOO1

[0115] Embodiments of the present invention may comprise or utilize a special purpose or general-purpose computer including computer hardware, as discussed in greater detail below. Embodiments within the scope of the present invention also include physical and other computer-readable media for carrying or storing computer-executable instructions and / or data structures. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer system. Computer-readable media that store computerexecutable instructions are physical storage media. Computer-readable media that carry computer-executable instructions are transmission media. Thus, by way of example, and not limitation, embodiments of the invention can comprise at least two distinctly different kinds of computer-readable media: physical computer- readable storage media and transmission computer-readable media.

[0116] Physical computer-readable storage media includes RAM, ROM, EEPROM, CD-ROM or other optical diskstorage (such as CDs, DVDs, etc.), magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store desired program code means in the form of computer-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer.

[0117] A“network” is defined as one or more data links thatenable thetransport of electronic data between computer systems and / or modules and / or other electronic devices. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or a combination of hardwired or wireless) to a computer, the computer properly views the connection as a transmission medium. Transmissions media can include a network and / or data links which can be used to carry desired program code means in the form of computer-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer. Combinations of the above are also included within the scope of computer-readable media.

[0118] Further, upon reaching various computer system components, program code means in the form of computer-executable instructions or data structures can be transferred automatically from transmission computer-readable media to physical computer-readable storage media (or vice versa). For example, computer-Attorney Docket 23812.7A / 15762WOO1 executable instructions or data structures received over a network or data link can be buffered in RAM within a network interface module (e.g., a “NIC”), and then eventually transferred to computer system RAM and / or to less volatile computer- readable physical storage media at a computer system. Thus, computer-readable physical storage media can be included in computer system components that also (or even primarily) utilize transmission media.

[0119] Computer-executable instructions comprise, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. The computer-executable instructions may be, for example, binaries, intermediate format instructions such as assembly language, or even source code. Although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the described features or acts described above. Rather, the described features and acts are disclosed as example forms of implementingthe claims.

[0120] Thoseskilled inthe art willappreciate thatthe invention may be practiced in network computing environments with many types of computer system configurations, including, personal computers, desktop computers, laptop computers, message processors, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, mobile telephones, PDAs, pagers, routers, switches, and the like. The invention may also be practiced in distributed system environments where local and remote computer systems, which are linked (either by hardwired data links, wireless data links, or by a combination of hardwired and wireless data links) through a network, both perform tasks. In a distributed system environment, program modules may be located in both local and remote memory storage devices.

[0121] Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Application-specificAttorney Docket 23812.7A / 15762WOO1Integrated Circuits (ASICs), Application-specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex ProgrammableLogic Devices (CPLDs), etc.

[0122] The present invention may be embodied in other specific forms without departing from its characteristics. Thedescribed embodiments areto be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaningand rangeof equivalency of the claims are to be embraced within theirscope.

Claims

Attorney Docket 23812.7A / 15762WOO1CLAIMSWhat is claimed is:1 . An intravascular lithotripsy (“IVL”) system with improved efficiency, comprising: an elongate member; a fluid-fillable enclosure formed of a material and surroundinga distalregion of the elongate member; at least one pair of spaced-apart electrodes operatively associated with the elongate member and within the fluid-fillable enclosure, wherein each pair of the at least one pair of spaced-apart electrodes form a spark gap; a fluid reservoir comprising a fluid and in operative fluid communication and association with an interior of the fluid-fillable enclosure, a voltage pulse generator comprising a capacitor bank and in operative electrical communication and association with the at least one pair of spaced-apart electrodes, the capacitor bank configured to store energy; and a controller in operative association with the voltage pulse generator and configured to control the voltage pulse generator to release at least some of the stored energy from the capacitor bank and apply the released energy to the spaced- apart electrodes, wherein the IVL system comprises a predetermined open gate duration that sets a predetermined maximum duration for application of energy to the spaced- apart electrodes, and wherein the predetermined maximum duration is less than40 microseconds.

2. The IVL system of claim 1 , further comprising an EPROM in operative association and communication with the controller, wherein the EPROM stores the predetermined open gate duration.

3. The IVL system of one or both of claims 1 and 2, wherein the predetermined maximum duration is within the group consisting of one or more of about 13 microseconds, about 14 microseconds, about 15 microseconds, about 15.5Attorney Docket 23812.7A / 15762WOO1 microseconds, about 20 microseconds, about 25 microseconds, about 30 microseconds, and about 35 microseconds.

4. The IVL system of one or both of claims 1 and 2, wherein the predetermined maximum duration provides at least about a 95% confidence distribution of successfully generated electrical arcs.

5. The IVL system of claim 4, wherein the predetermined maximum duration comprises at least 13 microseconds.

6. The IVL system of one or both of claims 1-2, wherein the predetermined maximum duration comprises a safety measure comprising a longer duration.

7. The IVL system of claim 6, wherein the safety measure comprising a longer duration results in a predetermined open gate condition that is within the group consisting of one or more of about 15 microseconds, about 15.5 microseconds, about20 microseconds, about25 microseconds, about30 microseconds, and about 35 microseconds.

8. The IVL system of one or both of claims 1 and 2, wherein the predetermined maximum duration provides at least about a 99% confidence distribution of successfully generated electrical arcs.

9. The IVL system of claim 8, wherein the predetermined maximum duration comprises at least 14 microseconds.

10. The IVL system of claim 9, wherein a safety measure comprising a longer duration results in a predetermined open gate condition that is within the group consisting of one or more of about 15 microseconds, about 15.5 microseconds, about 20 microseconds, about 25 microseconds, about 30 microseconds, and about 35 microseconds.Attorney Docket 23812.7A / 15762WOO11 1 . The IVL system of one or both of claims 1 and 2, wherein the predetermined maximum duration provides about a 100% confidence distribution of successfully generated electrical arcs.

12. The IVL system of claim 1 1 , wherein the predetermined maximum duration comprises at least 15.5 microseconds.

13. The IVL system of claim 12, wherein the predetermined maximum duration comprises a safety measure comprising a longer duration.

14. The IVL system of claim 14, wherein a safety measure comprising a longer duration results in a predetermined open gate condition that is within the group consisting of one or more of about 20 microseconds, about 25 microseconds, about 30 microseconds, and about 35 microseconds.

15. The IVL system of one or more of claims 1-14, wherein the IVL system is configured to generate a number of voltage pulses, wherein the number of generated voltage pulses is within the group consisting of one or more of 1-50 voltage pulses, 1- 100 voltage pulses, 1-200 voltage pulses, 1-300 voltage pulses, and more than 300 voltage pulses.

16. The IVL system of one or more of claims 1-15, wherein an actual duration of voltage required to generate an electrical arc is less than the predetermined maximum duration.

17. A method for ensuring generation of electrical arcs in an intravascular lithotripsy (“IVL”) system, comprising: providing an IVL system according to one or more of claims 1-16; initiating storage of energy within a capacitor bank; instructing with a controller, generation of a plurality of voltage pulses, each generated voltage pulse comprising a release of stored energy from the capacitor bank;Attorney Docket 23812.7A / 15762WOO1 applying each one of the generated voltage pulses in the plurality of voltage pulses to one or more pairs of spa ced-a part electrodes, wherein the applying of each one of the plurality of voltage pulses comprises a duration that ensures that at least about 95% of the applied voltage pulses in the plurality of voltage pulses generates an electrical arc between the spaced-apart electrodes.

18. The method of claim 17, wherein the applying of each one of the plurality of voltage pulses comprises a duration that ensures that at least about 99% of the applied voltage pulses in the plurality of voltage pulses generates an electrical arc between the spaced-apart electrodes.

19. The method of claim 17, wherein the applying of each one of the plurality of voltage pulses comprises a duration that ensures that about 100% of the applied voltage pulses in the plurality of voltage pulses generates an electrical arc between the spaced-apart electrodes.

20. An IVL catheter system, device and method as shown and described.

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