System and method for intravascular lithotripsy

Abstract

Apparatuses and method to deliver calibrated and / or oriented high energy shocks into a vascular lesion. These apparatuses may include a catheter having a balloon, and a plurality of acoustic emitters including insulating ring mounts within the balloon configured to convert electrical energy into oriented acoustic shock waves.

Description

SYSTEM AND METHOD FOR INTRAVASCULAR LITHOTRIPSYCLAIM OF PRIORITY

[0001] This patent application claims priority to U.S. provisional patent application no. 63 / 636,715, titled “SYSTEM AND METHOD FOR INTRAVASCULAR LITHOTRIPSY,” filed on April 19, 2024, and herein incorporated by reference in its entirety.INCORPORATION BY REFERENCE

[0002] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.FIELD

[0003] The methods and apparatuses described herein may be related to intravascular lithotripsy procedures. More specifically, the methods and apparatuses described herein may relate to apparatuses that may enable a surgeon to efficiently and easily perform lithotripsy procedures.BACKGROUND

[0004] The treatment of coronary and peripheral arterial obstructive lesions has become a main focus of vascular therapy in the last many decades. Originally this was done with balloon angioplasty. Ultimately coronary and peripheral stents were also used to enhance the long-term revascularization of arterial blockage. One of the great limitations of both angioplasty and stenting relates to the inability to adequately expand devices in areas where there is vascular calcification.

[0005] A number of devices have been devised to treat calcium. This includes rotational and orbital atherectomy, and most recently the advent of intravascular lithotripsy (IVL). IVL procedures create shockwaves within a blood vessel or other lumen as a means to disrupt or “crack” the calcifications. The shockwaves are typically centered within a balloon catheter, that is typically expanded at the time of the intravascular lithotripsy to further enhance the effects of the shockwaves.

[0006] During an intravascular lithotripsy (IVL) procedure, a clinician introduces a vascular catheter device through a blood vessel, to locate the distal end of the device at a desired treatment site. The clinician proceeds to use high energy pressure waves created bythe device, along with force imparted radially by a balloon, to modify (fracture and crack) calcified lesions in the vasculature

[0007] Conventional IVL treatments may suffer from high energy acoustic waves causing balloon rupture and / or pin holing over time. In some examples, balloons need to withstand repeated ~5Mpa / ~725psi / ~50atm pulses. Furthermore, some IVL systems may suffer from emitter erosion with repeated activations. The high voltage / high current used in IVL erodes the emitters (even at low energy). Thus, an IVL system that can support an increase in the number of pulses / activation is desired.SUMMARY OF THE DISCLOSURE

[0008] Described herein are apparatuses (e.g., systems and devices, including catheters), and methods to deliver intravascular lithotripsy (IVL) to a patient. In some examples, the IVL therapies may be delivered through a balloon assembly that may be coupled to an inner catheter and selectively sheathed by an outer catheter. In this manner, the outer catheter can protect and / or shield the balloon assembly from exposure to the arteries or veins. This shielding eases insertion and advancement of the balloon assembly. In some cases, the shielding allows longer balloon assemblies compared to conventional IVL assemblies.

[0009] For example, these apparatuses may be configured to deliver high energy shock waves to modify (fracture and crack) calcified vascular lesions. More particularly, described herein are catheters adapted to deliver high energy shock waves within a vascular lesion, to modify (fracture and crack) calcified portions of the lesion, comprising an improved percutaneous vascular lithotripsy catheter system.

[0010] The present disclosure describes systems and methods for producing and directing high energy intravascular pressure waves for fracturing and cracking calcified lesions in the vasculature. In general, the systems described herein include an energy source and an IVL catheter having a distal IVL device, including an interventional balloon and a series of pressure wave emitter arrays. During a calcified lesion modification / fracturing procedure, a clinician may advance the interventional balloon to a target treatment site in the vasculature and inflate the balloon with a fluid such as saline or contrast / saline combination, until the balloon outer surface contacts the target lesion inner wall. The clinician then activates the energy source, causing the emitter arrays to generate cavitation bubbles within the balloon, propagating a high energy pressure wave through the inflated balloon, and into the calcified lesions. A secondary pressure wave can also result from the collapse of the fluid cavitation and propagate towards the calcified lesions.

[0011] Typical IVL technologies suffer from a number of problems and limitations. The following table describes these limitations and the novel features, advantages and improvements of the presently described invention.

[0012] Conventional IVL systems can be laterally stiff or stiff along the catheter axis, due to their design features, which limits the device’s ability to navigate through tortuous anatomy that is commonly experienced when treating patients who suffer from vascular calcification.

[0013] Any of the devices described herein can be more flexible; navigates tighter bends, imparts less patient trauma and have a more flexible shaft because of the shorter emitter / ring mount design which does not employ shrink tubing and / or excessively long glue laminations. This trackability improvement manifests in faster procedure times for the clinician and more efficacy and safety for the patient due to less time under general anesthesia and less chance for vessel dissection due to device flexibility.

[0014] Some conventional “coronary” IVL systems have sub-optimal pushability due to rapid exchange (RX) / monorail designs. RX designs limit the device’s trackability and pushability, especially through tortuous anatomy due to the fact that they do not have a full length “rail” provided by the guidewire in which the catheter advances over. In an RX design only the distal section tracks over the guidewire which causes less smooth / reduced pushability and tracking of the catheter.

[0015] Any of the devices disclosed herein can provide more pushability and navigation control due to an over-the-wire (OTW) design which provides more column strength and torque strength, ability to navigate through more tortuous vasculature, and tracks further distally than typical RX devices allowing it to reach more distal lesions in the vasculature.

[0016] Conventional IVL systems may be limited in their ability to provide a suitable number of acoustic pressure “shocks” (i.e., have a limited number of acoustic “shots” for a single catheter). This limitation is primarily due to the short lifespan of their emitter designs. This limitation can cause a clinician to require the use of multiple catheters to effectively treat the patient.

[0017] In contrast, any of the devices disclosed herein can employ a more robust ring mount and emitter design features which allow for improved ‘wear’ resistance of the IVL system (i.e., provides for a more electrically robust / reliable emitter life over multiple ‘shock pulses’ with less emitter ‘erosion’ due to the multiple activations). Our design increases the number of acoustic pressure “shock pulses” / activations which can be delivered using a single catheter by approximately 2-5x. Additionally, design features of the ring mount and emitter help to rigidly set the ‘spark gap’ spacing between the emitter poles to ensureconsistent and reliable acoustic output. These improvements each help to decrease the overall procedure time, improve the overall catheter reliability, improve the safety due to fewer catheter exchanges, improve ease of use for the clinician and significantly decrease the procedure cost requiring only a single catheter per patient.

[0018] In particular, these methods and apparatuses may be configured to manage the connections (electrical connections) for these apparatuses to allow each acoustic emitter (which may include two or more pairs of electrodes) to be individually addressed. In some cases each acoustic emitter may be independently addressed; in some cases the acoustic emitter, even those that are individually addressable, may be controlled (e.g., by a control circuit configured to control the application of electrical energy to each of the acoustic emitters) to concurrently or nearly concurrently apply energy to drive sparking and the release of acoustic energy.

[0019] For example, described herein are apparatuses (and method of using them) comprising: an elongate catheter body; an inflatable balloon at a distal end region of the elongate catheter body; a plurality of acoustic emitters attached to the elongate catheter body within the inflatable balloon, wherein acoustic emitter comprises: an electrically insulating ring mount, a first emitter pair comprising a first pair of electrodes, a second emitter pair comprising a second pair of electrodes, and a first spark aperture formed through a surface of the ring mount that is radially outward of and between the first pair of electrodes; a second spark aperture formed through the surface of the ring mount that is radially outward of and between the second pair of electrodes, wherein each spark aperture forms a spark gap region; a control circuit configured to control the application of electrical energy to each of the acoustic emitters; an independently addressable electrical line extending proximally to the control circuit from a first electrode of the first pair of electrodes of each of the acoustic emitters; wherein a second electrode of the first pair of electrodes is electrically coupled to a first electrode of the second pair of electrodes of each of the acoustic emitters; and wherein a second electrode of the second pair of electrodes of each of the acoustic emitters is electrically coupled to a common electrical return line extending proximally to the control circuit.

[0020] The control circuit may be integrated into the catheter body. The control circuit may be configured to independently control the application of energy to each acoustic emitter. The plurality of acoustic emitters may comprise three or more acoustic emitters. In any of these apparatuses, each spark aperture may form a spark gap region having a concave surface that is configured to focus released acoustic energy. The concave surface of each of the spark apertures may comprise an acoustically reflective material.

[0021] Each acoustic emitter of the plurality of acoustic emitters may be attached to the elongate catheter body at a discrete contact point. Each emitter pair may be held between an outer surface of the ring mount and an outer surface of the elongate catheter body. The ring mount may cover the radially outer surface of each emitter pair. The at least one of the plurality of acoustic emitters may be axially movable relative to the balloon. At least one of the plurality of acoustic emitters may be radially movable relative to the balloon.

[0022] In The first and second spark apertures of each acoustic emitter may be oriented in a radially offset position relative to an adjacent acoustic emitter. Any of these apparatuses may include an arc generator configured to generate a high voltage pulse sufficient to create a plasma arc between the emitters or the emitter pair resulting in a mechanical shock wave within the balloon.

[0023] The ring mount may comprise a plurality of ribs extending longitudinally from an outer region of the ring mount to the elongate catheter body, wherein the first spark aperture is formed, in part, by a gap in a rib between the first pair of electrodes. The ring mount may be formed of any electrically insulating material, such as a polymeric insulating material (including but not limited to: silicones, polyethylene, epoxy resins, composites, etc.). The electrodes of the first emitter pair may be separated by one or more ribs of the plurality of ribs.

[0024] Conventional IVL systems have non-adjustable unidirectional emitters making it difficult to target specific lesions for example in the case of nodal, eccentric and / or focal calcified lesions in the vasculature. Such conventional systems may also either require addressing all of the acoustic emitters together (e.g., in series), and / or may be connected (wired) to the electrical source of energy in a manner that results in a loss of flexibility, due in part to the arrangement of connections.

[0025] Any of the devices disclosed herein can include adjustable ring mount emitter arrays which can be moved axially and radially within the balloon allowing the user to target specific lesions without deflating or re-positioning the moving the balloon catheter. This advantage provides for a faster procedure time, ease of use and the ability to focally treat difficult nodal / eccentric calcium or even just areas of more heavily calcified diffuse calcium in the anatomy.

[0026] Conventional IVL systems typically employ balloons that are relatively short, forcing clinicians to deflate / reposition / inflate the device multiple times to treat long lesions leading to long procedure times. Any of the devices disclosed herein can include a longer interventional balloon (i.e., longer treatment length) without requiring multiple deflation / reposition / inflation steps to effectively treat the lesion which provides the advantageof a faster procedure time, ease of use and improved safety for the patient. These apparatuses may allow individually addressing one or more acoustic emitters along the length of the device (within the balloon) permitting greater control and flexibility in positioning and therefore treatment.

[0027] Conventional IVL systems may also have inefficient emitter arrays requiring increased drive energy and more acoustic “shocks” to effectively modify (crack / fracture) the calcium in the lesion. In some embodiments, a ring mount and emitter design of the apparatuses described herein can provide for improved higher efficiency acoustic amplification using a waveguide / funnel / aperture design (Acoustic Waveguide Design) which allows for higher acoustic pressure using less drive energy and requiring fewer acoustic “shocks” to effectively modify calcium. Additionally, design features of the ring mount and emitter help to rigidly set the ‘spark gap’ spacing between the emitter poles to ensure consistent and reliable acoustic output. This ring mount emitter high efficiency design ultimately leads to a smaller energy system design, faster procedure times and improved ease of use.

[0028] Conventional IVL systems function with a preset emitter firing sequence which prevents the clinician from selectively using individual emitters or sets of emitters during the treatment (i.e., not user selectable). This limitation limits the ability of the user to target difficult vascular lesions, for example in the case of nodal, eccentric and / or focal calcified lesions in the vasculature.

[0029] Any of the systems disclosed herein may allow for independent user selectable emitters / channels (i.e., location / directional control) which enables custom treatment and ‘aiming’ of the acoustic output for treating difficult nodal, eccentric, and / or focal lesions as well as heavily calcified locations within a diffuse lesion. This advantage provides for the ability to target specific areas without requiring the balloon deflation / inflation and repositioning of the IVL balloon within the lesion providing for faster procedure times and improved clinical safety.

[0030] Conventional IVL system designs use complex / intricate components and assembly processes which are expensive and result in high reject rates during production. These designs often use stiff shrink tubing processes for mounting the emitters and creating large crossing profiles for the catheter.

[0031] Any of the designs disclosed here can use concentric ring mounts (CRM) and emitter design which facilitates ease of assembly, provides for a more electrically robust / reliable emitter life over multiple ‘shock pulses’ (i.e., improved ‘wear’ resistance with less emitter ‘erosion’), improved production yield, faster assembly time and associateddecreased production costs as well as facilitates a smaller device crossing profile which is more flexible and deliverable due to the shorter axial length of the CRM. Additionally, the CRM feature helps to rigidly set the ‘spark gap’ spacing between the emitter poles to ensure consistent and reliable acoustic output.

[0032] In general, the acoustic emitters described herein may include a ring mount which fits over the outer surface of the catheter, within the balloon region. The ring mount may be an electrically insulating material and may have an outer cylindrical ring region and multiple projections (e.g., ridges, ribs, etc.) extending from the outer cylindrical ring body radially inward to contact the outer surface of the catheter (or to extend towards the outer surface to contact an inner cylindrical ring body). Each acoustic emitter may include one or more pairs of electrodes. The insulating ring mount may be formed of any appropriate electrically insulating material. The projections may extend, e.g., as a ridge or rib, along the longitudinal length within the ring mount and may provide longitudinal channels for the electrodes forming the one or more emitter pairs of the acoustic emitter. The spark aperture may be formed through the ring mount. In some cases the spark aperture forms an opening in one or more of the longitudinally extending projections (e.g. ribs).

[0033] The one or more pairs of electrodes may each include a first electrode and a second electrode that are spaced apart from each other and may have exposed surfaces (e.g., exposed to the electrically conductive fluid within the balloon) on either side of the spark gap. Each electrode may include one or more conductive surfaces from which sparks may be generated within the fluid. Pairs of electrodes within each acoustic emitter may share electrodes between each pair, e.g., a first emitter pair may include a first electrode that is arranged across from a second electrode at a first spark gap (on either side of a first spark aperture) and a second emitter pair may include a third electrode that is arranged across from the second electrode at a second spark gap (on either side of a second spark aperture). In general, the first emitter pair and the second emitter pair share an electrode.

[0034] Conventional IVL systems require users to rely on the inflation device (i.e., catheter indeflator) to monitor balloon pressure which is often used to indicate completeness of treatment (i.e. successful modification of the calcium). This limitation requires the user to visually be the judge of treatment completion and leaves room for variation in patient outcomes. In some embodiments, a disclosed IVL system can provide simultaneous and automatic catheter integrated balloon pressure monitoring using a pressure sensor within the catheter and a generator monitoring algorithm to help the user determine when a procedure is complete (i.e., successful calcium modification was achieved). A pressure drop along with a visual improvement of the balloon "waist" indicates successful calcium modification.Additionally, large / significant pressure drops can be used to indicate a leak (e.g., a "pin- holed" leak) within the balloon and provide automatic cessation of therapy for safety control. These advantages all improve the efficacy and safety of the treatment for the patient and the ease of use for the user.

[0035] Conventional IVL systems may prevent acoustic activation after a series of 10 “shock pulses” and may require the user to wait, e.g., for 10s, before reactivating acoustic “shocks” as well as deflate / inflate the balloon multiple times to cool the fluid in the balloon to prevent thermal buildup which could thermally damage the vascular tissue.

[0036] In one embodiment, a disclosed design includes a thermocouple, thermistor and / or RTD temperature sensor that measures and monitors the temperature of the acoustic coupling fluid medium (i.e., saline and contrast) in the balloon in order to automatically prevent acoustic activation when the thermal build up in the balloon reaches too high a value. This may allow the system or user to determine if it is necessary to wait for thermal cooling and / or deflate the balloon to prevent thermal heat buildup which means that if there is only slight rise in temperature during treatment the system would not automatically require a wait time after a pre-defined sequence of pulses. This advantage provides for a much faster procedure time and improved safety for the patient by preventing any unnecessary thermal damage to the vascular tissue.

[0037] Conventional IVL systems may have a pre-determined or ‘set’ acoustic output energy which is delivered to the lesion. This may limit the calcium modification capabilities of the system, for example in difficult anatomies or heavily calcified lesions the current systems offer only one level of acoustic pressure output. In some implementations, a disclosed system may have continuously selectable or modally selectable acoustic output. It allows for adjustment of acoustic pressure output across a continuous range from low level pressures for example 2MPa up to 5MPa and greater, or alternatively a multi-modal selection which allows the use to switch between standard output (boost) mode and high output mode perhaps based on a scaler for example 25% greater output than the standard output. This advantage allows for improved therapeutic control of the acoustic energy delivered to the vascular calcium which provides for faster procedure times, ability to treat heavily calcified lesions with more energy improving the efficacy of the calcium modification and improves the results of the overall angioplasty procedure.

[0038] Any of these apparatuses may be configured to activate the acoustic pressure wave at a scaled / increased level from a standard level. For example, if the standard treatment level uses 3kV of voltage to achieve desired acoustic pressure output, then a scalar of 25% may be used to boost the output to 3kV x 1.25% = 3.75kV. This may be selectable by the user or hardcoded into appropriate catheters that the generator may sense and automatically set the system to high-output mode.

[0039] Conventional IVL technologies may suffer from logistical and sterility challenges associated with the catheter-to-generator power cable being a separate non-sterile system component. These designs require the non-sterile cable to be either autoclaved prior to the procedure or sterile “socked” during the procedure where a sleeve is required to protect the non-sterile components from the patient. Additionally, this separate cable component is burdened by the need to continually located the cable within the medical facility before each procedure which can cause significant delay in a clinician’s practice.

[0040] Some embodiments described herein address this by including an integrated (or attached) power cable with the therapeutic IVL catheter. The catheter includes a short ‘pigtail’ section from the tri-arm catheter hub to the start / stop activation hub to ensure a very flexible and non-pulling design which enables the OTW catheter to track smoothly during the procedure. The power cable then transitions from the catheter hub to an integrated / attached power cable which are all pre-sterilized by the manufacturer and which are disposable along with the catheter after the procedure. The advantages of this design include not requiring a pre-autoclave of a separate cable, not requiring the user to “sterile sock” the cable to ensure sterility during the procedure, and prevents significant time delays due to problems locating the separate power cable prior to procedures.

[0041] For example, described herein are apparatuses comprising: an elongate catheter body; an inflatable balloon at a distal end region of the elongate catheter body; a plurality of acoustic emitters attached to the elongate catheter body within the inflatable balloon, wherein acoustic emitter comprises: an electrically insulating ring mount; a first emitter pair comprising a first pair of electrodes; a second emitter pair comprising a second pair of electrodes; and a first spark aperture formed through a surface of the ring mount that is radially outward of and between the first pair of electrodes; a second spark aperture formed through the surface of the ring mount that is radially outward of and between the second pair of electrodes; wherein each spark aperture forms a spark gap region having a concave surface that is configured to focus released acoustic energy.

[0042] The plurality of acoustic emitters may be attached to the elongate catheter body at a plurality of discrete contact points, as described above. For example, each emitter pair may be held between an outer surface of the ring mount and an outer surface of the elongate catheter body. A radially outer surface of each emitter pair may be covered by the ring mount. In any of these apparatuses, the concave surface of each of the spark apertures comprises an acoustically reflective material.

[0043] Any appropriate acoustically reflective material may be used, including generally hard, smooth, and non-porous materials; non-limiting examples may include glass, metal and polymeric materials that do not absorb sound well, instead reflecting greater than a threshold of the sound (e.g., having a sound absorption coefficient of 0.3 or less, 0.25 or less, 0.2 or less, 0.15 or less, 0.1 or less, 0.1 or less, 0.09 or less, 0.08 or less, 0.07 or less, 0.06 or less, 0.05 or less, 0.04 or less, 0.03 or less, etc.) at frequencies within the lithotripsy range (e.g., greater than 10 kHz, 15 kHz, 20 kHz, 25 kHz, 30 kHz, 35 kHz, 40 kHz, 50 kHz, 60 kHz, 100 kHz, 200 kHz, between 10 kHz and 1 MHz, etc.).

[0044] In any of these apparatuses, the at least one of the plurality of acoustic emitters may be movable within the balloon (e.g., may be axially movable relative to the balloon and / or radially movable relative to the balloon). The first and second spark apertures of each acoustic emitter may be oriented in a radially offset position relative to an adjacent acoustic emitter.

[0045] Any of these apparatuses may include an electrical generator (e.g., an arc generator) configured to generate a high voltage pulse sufficient to create a plasma arc between the emitters or the emitter pair resulting in a mechanical shock wave within the balloon.

[0046] As mentioned, the ring mount may comprise a plurality of ribs extending longitudinally from an outer region of the ring mount to the elongate catheter body, wherein the first spark aperture may be formed, at least in part, by a gap in a rib between the first pair of electrodes. The electrodes of the first emitter pair may be separated by one or more ribs of the plurality of ribs.

[0047] Any of these apparatuses may include a control circuit that is configured to control the application of electrical energy to each of the acoustic emitters. The control circuit may include one or more processors (e.g., microprocessors), memory, control logic, etc. to control operation of the apparatus, and in particular to select and control energy to one or more of the acoustic emitters. In some cases the control circuit may be integrated into the catheter body. In some examples the control circuit may be integrated into a handle. The emitter pair on each ring mount of the plurality of acoustic emitters may be individually addressable by a controller configured to control the application of energy to each emitter pair; the control circuit may control individually (and in some cases, independently) addressing each acoustic emitter by controlling the application of energy to the electrodes of the acoustic emitter.

[0048] For example, an apparatus may include: an elongate catheter body; an inflatable balloon at a distal end region of the elongate catheter body; a plurality of acoustic emittersattached to the elongate catheter body at a plurality of discrete contact points and within the inflatable balloon, wherein each acoustic emitter comprises: an electrically insulating ring mount; an emitter pair, wherein each emitter of the emitter pair is held between an outer surface of the ring mount and an outer surface of the elongate catheter body; and a spark aperture formed through a radially outward surface of the ring mount between the emitters of the emitter pair that is configured to focus released acoustic energy.

[0049] All of the methods and apparatuses described herein, in any combination, are herein contemplated and can be used to achieve the benefits as described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0050] A better understanding of the features and advantages of the methods and apparatuses described herein will be obtained by reference to the following detailed description that sets forth illustrative embodiments, and the accompanying drawings of which:

[0051] FIG. l is a simplified block diagram of an example intravascular lithotripsy (IVL) system.

[0052] FIG. 2 is a block diagram showing some example components of the generator of FIG. 1.

[0053] FIG. 3 is an example view of a distal end of the balloon assembly.

[0054] FIG. 4A shows details of the balloon assembly of FIG. 1.

[0055] FIG. 4B shows a perspective view of the balloon assembly of FIG. 1.

[0056] FIG. 4C shows the balloon assembly of FIG. 1 inserted into a blood vessel with the balloon inflated.

[0057] FIG. 4D shows the balloon assembly of FIG. 1 with the balloon inflated.

[0058] FIG. 5 shows an example view of the distal tip of the balloon assembly of FIG. 1.

[0059] FIG. 6 shows an example of an acoustic emitter assembly.

[0060] FIG. 7 shows another example of an acoustic emitter assembly with possible dimensions, although other sizes are possible.

[0061] FIG. 8 shows another view of a hub assembly.

[0062] FIG. 9 shows an example catheter handle assembly.

[0063] FIG. 10 shows an example cable assembly.

[0064] FIG. 11 A shows another view of the catheter handle of FIG. 9.

[0065] FIG. 1 IB shows the catheter handle of FIG. 9 and a view of the balloon assembly of FIG. 3.

[0066] FIG. 12 shows example packaging for shipment of the cable assembly of FIG. 10.

[0067] FIG. 13 shows other example views of the IVL system of FIG. 1.

[0068] FIG. 14 shows an example view of a generator for use with the IVL system ofFIG. 13.

[0069] FIG. 15 shows an example circular emitter.

[0070] FIG. 16 shows an example spark plug gap emitter.

[0071] FIG. 17 shows an example circular emitter.

[0072] FIG. 18 shows an example ring mount.

[0073] FIG. 19 shows a view of the example ring mount of FIG. 18 disposed on a catheter.

[0074] FIG. 20 shows another view of the ring mount disposed on a catheter.

[0075] FIG. 21 shows a ring mount. FIG. 22. shows another ring mount.

[0076] FIGS. 22-23 show another example ring mount.

[0077] FIG. 24 shows a ring mount.

[0078] FIG. 25 shows an assembly with example ring mounts.

[0079] FIG. 26 shows a view of a center ring assembly.

[0080] FIG. 27 shows a center ring assembly without a ring mount.

[0081] FIG. 28 shows an example of an open spark gap with no surrounding reflective surfaces.

[0082] FIG. 29 shows an example of a spark gap with reflective surfaces.

[0083] FIG. 30 shows an example of a spark gap with shallow waveguide aperture.

[0084] FIG. 31 shows an example of a spark gap with a deep waveguide aperture.

[0085] FIG. 32 shows an aperture design with no floor.

[0086] FIG. 33 shows an aperture design.

[0087] FIG. 34A shows an example aperture with a shallow aperture.

[0088] FIG. 34B shows an example aperture with a deep aperture.

[0089] FIG. 35 A shows a ring mount with a thicker floor thickness.

[0090] FIG. 35B shows a ring mount with a wider hole.

[0091] FIG. 36 shows a side view of a ring mount with a feature to control a spark gap between emitter elements.

[0092] FIG. 37 shows a table of ring mount characteristics and associated profiles.

[0093] FIG. 38A shows a view of a ring mount disposed on a catheter.

[0094] FIG. 38B shows a side view of the ring mount.

[0095] FIG. 39A shows a skeleton view of a ring mount assembly.

[0096] FIG. 39B shows a voltage jumping from the first emitter to a second emitter.

[0097] FIG. 39C shows a voltage passing from the second emitter through an “S” jumper wire to a third emitter.

[0098] FIG. 39D shows a voltage passing from the third emitter to the fourth emitter and creating another spark.

[0099] FIG 39E shows a voltage passing through the fourth emitter and to the generator.

[0100] FIG. 39F shows acoustic waves emanating from apertures in the ring mount.

[0101] FIG. 40 shows an example assembly that includes three ring emitters disposed on a catheter.

[0102] FIG. 41 is a schematic diagram of a ring mount assembly.

[0103] FIG. 42A shows an example catheter assembly with three ring mount assemblies.

[0104] FIG. 42B shows the catheter assembly configured for three channel control.

[0105] FIG. 43 shows a view of the ring mount assemblies of FIG. 42B.

[0106] FIG. 44 shows example wiring implementations of various ring mount configurations.

[0107] FIG. 45 shows a wiring diagram that may be used to implement a three-ring mount assembly.

[0108] FIG. 46A shows a first view of a wiring implementation of the wiring diagram of FIG. 45.

[0109] FIG. 46B shows a second view of the wiring implementation of the wiring diagram of FIG. 45.

[0110] FIG. 47 shows example C and S cable interconnections.[OHl] FIG. 48 shows an example C cable interconnection.

[0112] FIG. 49 shows an example ring mount with internal electrical interconnections.

[0113] FIG. 50 shows a view of the balloon assembly.

[0114] FIG. 51 shows a view of a ring mount disposed on a catheter.

[0115] FIG. 52 shows a view of multiple ring mount assemblies disposed on a catheter.

[0116] FIG. 53 shows a balloon assembly of an IVL system.

[0117] FIG. 54 shows the ring mounts repositioned with respect to the blood vessel.

[0118] FIG. 55 shows a proximal ring mount assembly delivering sonic pulses toward the nodal calcium deposit.

[0119] FIG. 56 shows how the catheter may be rotated thereby directing apertures of any ring mount assemblies toward a particular location of the blood vessel.

[0120] FIG. 57 shows sonic or acoustic waves radiating from a ring mount toward a nodal calcium deposit.

[0121] FIG. 58 A shows an example ring mount that includes a radiopaque marker.

[0122] FIG. 58B shows the ring mount in a first position.

[0123] FIG. 58C shows the ring mount in a second position.

[0124] FIG. 58D shows the ring mount is rotated so that the radiopaque marker faces into the page.

[0125] FIG. 58E shows the ring mount is rotated such that the radiopaque marker faces upward while the apertures face into and out of the page.

[0126] FIG. 59 is a block diagram of an example high voltage power supply.

[0127] FIG. 60 shows example screens.

[0128] FIG. 61 shows different views of the high voltage generator.

[0129] FIG. 62 shows a block diagram of an example high voltage generator.

[0130] FIG. 63 shows a block diagram of another example high voltage generator.

[0131] FIG. 64 shows a block diagram of another example high voltage generator.

[0132] FIG. 65 shows a block diagram of another example high voltages generator.

[0133] FIG. 66 shows a table comparing different power supply designs.

[0134] FIG. 67 shows an example implementation of rings and an associated array.

[0135] FIG. 68 A shows a possible user interface based on the array of FIG. 67.

[0136] FIG. 68B shows the user interface after the user has turned on rings 1, 3, and 4 (by touching either oval 1 or oval 4, and touching oval 3.

[0137] FIGS. 69 A and 69B show current flow for each of the halves of the drive signal for the worst-case scenario (device started with a short at the output, all capacitors discharged).

[0138] FIG. 69C shows a schematic of a high voltage divider and a short protection resistor.

[0139] FIG. 69D shows the start time of the device (4kV output voltage, all capacitors discharged, worst case scenario).

[0140] FIG. 70 shows a schematic of an example output stage with bleeder resistors.

[0141] FIG. 71 A shows a breadboard implementation of a high voltage generator.

[0142] FIG. 71B shows an enclosure surrounding the power supply of FIG. 71 A.DETAILED DESCRIPTION

[0143] In general, intravascular lithotripsy apparatuses and methods can be used to treat calcified arteries or other lumens. Traditional lithotripsy balloons have numerous limitations and challenges that limit their ability to deliver shockwaves, to disrupt calcified lesions, and / or to permit insertion and placement through clogged or twisting arteries.

[0144] The apparatuses (e.g., devices and / or systems) and methods described herein for producing and directing high energy intravascular pressure waves for fracturing and cracking calcified lesions in the vasculature may address many of the limitations with currently described and available systems. In general, the apparatuses described herein may include an energy source and an intravascular lithotripsy (IVL) catheter having a distal IVL mechanism including an interventional balloon and a plurality of pressure wave emitter arrays. The IVL mechanism may include one or more ring mount assemblies supporting and controlling the formation of the spark and directing / focusing the released acoustic energy.

[0145] During a calcified lesion modification / fracturing procedure using the apparatuses described herein, a clinician may advance the interventional balloon to a target treatment site in the vasculature and inflate the balloon with a fluid such as saline or contrast / saline combination, until the balloon outer surface contacts the target lesion inner wall. The clinician then activates the energy source, causing the emitter arrays to generate cavitation bubbles within the balloon, propagating a high energy pressure wave through the inflated balloon, and into the calcified lesions. A secondary pressure wave can also result from the collapse of the fluid cavitation and propagates towards the calcified lesions.

[0146] The apparatuses described herein may have an enhanced lateral flexibility along the long axis of the catheter, in contrast to existing IVL technologies. For example, a typical IVL system is laterally stiff or stiff along the catheter axis, as they typically embed the sparkgenerating features (e.g., electrodes) along the axis in a rigid configuration, which limits the device’s ability to navigate through tortuous anatomy that is commonly experienced when treating patients who suffer from vascular calcification. The apparatuses described herein may be more flexible and may be capable of navigating tighter bends, imparting less patient trauma and may have a more flexible shaft because of the configuration of the ring mount (also referred to herein as a ring mount assembly) that may be part of an acoustic emitter attached to the elongate catheter body. The ring mounts described herein are typically relatively short cylindrical bodies and may not need to use a shrink tubing and / or excessively long glue laminations. The ring mounts may be formed as annular structures that contact the central shaft of the catheter at discrete regions or points, e.g., suspending the emitters (e.g., electrodes) in discrete regions outside of the shaft. This trackability improvement may manifest in faster procedure times for the clinician and more efficacy and safety for the patient due to less time under general anesthesia and less chance for vessel dissection due to device flexibility.

[0147] The apparatus and devices described herein may also include a modified monorail configuration that may provide enhanced “pushability” (e.g., for inserting / positioning theapparatus) as. Traditional rapid exchange (“RX”) designs limit the trackability and pushability, especially through tortuous anatomy due to the fact that they don’t have a full length “rail” provided by the guidewire in which the catheter advances over. In an RX design only the distal section tracks over the guidewire which causes less smooth / reduced pushability and tracking of the catheter. The apparatus described herein may be configured a “coronary” apparatus having better pushability and navigation control due to an over-the-wire (OTW) design which provides more column strength and torque strength, ability to navigate through more tortuous vasculature, and tracks further distally than typical RX devices allowing it to reach more distal lesions in the vasculature.

[0148] Typical IVL systems are also limited in their ability to provide a suitable number of acoustic pressure “shocks” (i.e., have a limited number of acoustic “shots” for a single catheter). This limitation is primarily due to the short lifespan of the emitter. This may require the use of multiple catheters to effectively treat the patient. The apparatuses and methods described herein may include a ring mount and emitter configuration that allows for improved ‘wear’ resistance of the IVL system. This may provide for a more electrically robust / reliable emitter life over multiple ‘shock pulses’ with less emitter ‘erosion’ due to the multiple activations. The ring mounts as described herein may increase the number of acoustic pressure “shock pulses” and / or activations which can be delivered using a single catheter by approximately 2x-5x. These ring mounts may also be configured to position the emitter and to focus / guide the emitted shock by configurating the ‘spark gap’ spacing between the emitter poles in a precisely controlled manner to ensure consistent and reliable acoustic output. These improvements each help to decrease the overall procedure time, improve the overall catheter reliability, improve the safety due to fewer catheter exchanges, improve ease of use for the clinician and significantly decrease the procedure cost requiring only a single catheter per patient.

[0149] Typical IVL systems also have fixed, unidirectional emitters making it difficult to target specific lesions for example in the case of nodal, eccentric and / or focal calcified lesions in the vasculature. In contrast, the apparatuses and methods described herein may include an adjustable ring mount emitter array which can be moved axially and radially within the balloon allowing the user to target specific lesions without deflating or repositioning the balloon catheter. This advantageously provides for a faster procedure time, ease of use and the ability to focally treat difficult nodal / eccentric calcium or even just areas of more heavily calcified diffuse calcium in the anatomy. In addition, multiple different emitters may be positioned at different known circumferential regions and / or different axial(longitudinal) regions (e.g., on different ring mounts). To allow the user to rotate and / or adjust axial position of the emitters to target focal lesions.

[0150] In general, typical IVL systems employ balloons that have a limited, relatively short, length, forcing clinicians to deflate / reposition / inflate the device multiple times to treat long lesions leading to long procedure times. As illustrated below, the apparatuses (and methods of using them) described herein may provide a longer interventional balloon (i.e., longer treatment length) without requiring multiple deflation / reposition / inflation steps to effectively treat the lesion which provides the advantage of a faster procedure time, ease of use and improved safety for the patient.

[0151] Typical IVL systems may have inefficient emitter arrays requiring increased drive energy and more acoustic “shocks” to effectively modify (crack / fracture) the calcium in the lesion. The methods and apparatuses described herein may provide for improved higher efficiency acoustic amplification using a waveguide / funnel / aperture design (e.g., an “Acoustic Waveguide Design” or AWDTM) which allows for higher acoustic pressure using less drive energy and requiring fewer acoustic shocks to effectively modify calcium. Additionally, design features of the ring mount and emitter may help to rigidly set the ‘spark gap’ spacing between the emitter poles to ensure consistent and reliable acoustic output. This ring mount emitter may have a high efficiency design ultimately lead to a smaller energy system design, faster procedure times and improved ease of use.

[0152] Unlike typical IVL systems, the apparatuses and methods described herein may be configured to provide a variety of, including custom, firing patterns. Typical IVL systems have a preset emitter firing sequence which does not allow the clinician to select or use individual emitters or sets of emitters during the treatment (i.e., not user selectable). This limits the ability of the user to target difficult vascular lesions for example in the case of nodal, eccentric and / or focal calcified lesions in the vasculature. In contrast, the methods and apparatuses described herein are adapted to allow independent user selectable emitters / channels (i.e., location / directional control) which enables custom treatment and ‘aiming’ of the acoustic output for treating difficult nodal, eccentric, and / or focal lesions as well as heavily calcified locations within a diffuse lesion. This provides for the ability to target specific areas without requiring the balloon deflation / inflation and repositioning of the IVL balloon within the lesion providing for faster procedure times and improved clinical safety.

[0153] Typical IVL system designs may also require complex / intricate components and assembly processes which are expensive and result in high reject rates during production. These designs often use stiff shrink tubing processes for mounting the emitters and creating large crossing profiles for the catheter. In contrast the apparatuses described herein includeconcentric ring mounts (CRM) and emitter designs that may be significantly easier to assemble, and may provide for a more electrically robust / reliable emitter life over multiple ‘shock pulses’ (i.e., improved ‘wear’ resistance with less emitter ‘erosion’), improved production yield, faster assembly time and associated decreased production costs as well as facilitates a smaller device crossing profile which is more flexible and deliverable due to the shorter axial length of the CRM. Additionally, the CRM feature helps to rigidly set the ‘spark gap’ spacing between the emitter poles to ensure consistent and reliable acoustic output.

[0154] Typical IVL systems may require users to rely on the inflation device (i.e., catheter indeflator) to monitor balloon pressure which is often used to indicate completeness of treatment (i.e. successful modification of the calcium). This may require the user to visually judge when treatment is complete and leaves room for variation in patient outcomes. The methods and apparatuses described herein may provide for simultaneous, automatic and catheter-integrated balloon pressure monitoring using a pressure sensor within the catheter and a generator monitoring algorithm to help the user determine when a procedure is complete (i.e., successful calcium modification was achieved). A pressure drop along with a visual improvement of the balloon "waist" may indicate successful calcium modification. Additionally, large / significant pressure drops can be used to indicate a ‘pin-holed’ balloon and provide for automatic cessation of therapy for safety control. These advantages all improve the efficacy and safety of the treatment for the patient and the ease of use for the user.

[0155] Typical IVL systems may prevent acoustic activation after small number (e.g., 10) of “shock pulses” applied in succession (e.g., as a series), and may require the user to wait for some predetermined time period (e.g., 10s) before reactivating acoustic “shocks” and may also require the user to deflate / re-inflate the balloon multiple times to cool the fluid in the balloon to prevent thermal buildup, which could thermally damage the vascular tissue. The methods and apparatuses described herein may include a temperature sensor (e.g., a thermocouple, thermistor or RTD temperature sensor) that measures and monitors the temperature of the acoustic coupling fluid medium (i.e., saline and / or contrast) in the balloon in order to automatically prevent acoustic activation when the thermal build up in the balloon reaches too high a value. This advantageously allows the system or user to determine if it is necessary to wait for thermal cooling and / or deflate the balloon to prevent thermal heat buildup; if there is only a slight rise in temperature during treatment, the system may not automatically require a wait time after a pre-defined sequence of pulses. This may also provide for a much faster procedure time and improved safety for the patient by preventing any unnecessary thermal damage to the vascular tissue.

[0156] Similarly, typical IVL systems may have a pre-determined or ‘set’ acoustic output energy which is delivered to the lesion. This may limit the calcium modification capabilities of the system, for example in difficult anatomies or heavily calcified lesions the current systems offer only one level of acoustic pressure output. The apparatuses and methods described herein may include a continuously selectable or modally selectable acoustic output that may allow for adjustment of acoustic pressure output across a continuous range from low level pressures (for example, 2MPa up to 5MPa and greater), or alternatively a multi-modal selection which allows the use to switch between standard output (boost) mode and high output mode perhaps based on a scaler for example 25% greater output than the standard output. This may advantageously allow for improved therapeutic control of the acoustic energy delivered to the vascular calcium which provides for faster procedure times, the ability to treat heavily calcified lesions with more energy improving the efficacy of the calcium modification and may improve the results of the overall angioplasty procedure. In general, these methods and apparatuses may be configured to activate the acoustic pressure wave at a scaled / increased level from the standard level. For example, if the standard treatment level uses 3kV of voltage to achieve desired acoustic pressure output, then a scaler of 25% would boost the output to 3kV x 1.25% = 3.75kV. This could be selectable by the user or hard coded into appropriate catheters so that the generator would sense and automatically set the system to high-output mode.

[0157] Typical IVL technologies also suffer from logistical and sterility challenges when the catheter-to-generator power cable is a separate non-sterile system component. These designs may require the non-sterile cable to be either autoclaved prior to the procedure or sterile “socked” during the procedure where a sleeve is required to protect the non-sterile components from the patient. Additionally, this separate cable component may be burdened by the need to continually located the cable within the medical facility before each procedure which can cause significant delays in a clinician’s practice.

[0158] The methods and apparatuses described herein may instead be configured to include an integrated (or attached) power cable with the therapeutic IVL catheter. The catheter may include a short ‘pigtail’ section from the tri-arm catheter hub to the start / stop activation hub to ensure a very flexible and non-pulling design which enables the OTW catheter to track smoothly during the procedure. The power cable may then transition from the catheter hub to an integrated / attached power cable which are all pre-sterilized by the manufacturer and which are disposable along with the catheter after the procedure. The advantages of this design may include not requiring a pre-autoclave of a separate cable, not requiring the user to “sterile sock” the cable to ensure sterility during the procedure, andprevents significant time delays due to problems locating the separate power cable prior to procedures.

[0159] The figures described below may include all or some of these features, and any of the variations described herein may include one or more of them, in any reasonable combination.

[0160] FIG. l is a simplified diagram of an example intravascular lithotripsy (IVL) system 100. The IVL system 100 may include a high voltage generator, a cable, a catheter hub, a cable assembly, and a balloon assembly. The high voltage generator may include systems and devices to control one or more aspects of the IVL system 100, including operations of the balloon assembly. For example, the high voltage generator may provide energy (voltage and / or current) to the balloon assembly 140. The energy may be used to induce one or more arcs between electrodes enclosed in the balloon assembly. The arcs may deliver shockwaves (pressure waves) to a treatment area or region. The energy may be provided to the balloon assembly from the high voltage generator through a removably coupled cable. The cable may be coupled to the catheter hub which may be coupled through one or more catheters (included in the catheter assembly) to the balloon assembly.

[0161] Any fluids for inflating the balloon assembly can be administered through the catheter hub. In addition, the catheter hub may enable a clinician (physician or other trained personnel) to control and introduce the balloon assembly and a catheter assembly percutaneously into a patient.

[0162] The IVL system 100 may include a low profile and flexible catheter and / or catheter assembly. The catheter and / or catheter assembly may be advanced into a lumen to modify calcified lesion in the most distal coronary and peripheral vasculature that other (conventional) technologies cannot reach. In some examples, the IVL system 100 may provide support, deliverability, and intubation depth advantages over conventional monorail technologies.

[0163] In some examples, the balloon and / or balloon assembly may be thirty millimeters long (which may be twice as long as conventional IVL balloons). This length may allow for treatment of longer lesion segments with less repositioning. Some balloon assemblies may include three acoustic emitters to provide improved lesion coverage compared to conventional IVL solutions.

[0164] In some examples, the IVL system 100 may have a minimum two hundred pulse activation limit. This pulse limit may enable acoustic shock treatment with a single catheter thereby enabling a single catheter to be used for complex treatments. The IVL system 100may provide integrated treatment activation and a pre-sterile cable thereby obviating the need for locating a separate cable, handle, and sterile sleeve for performing procedures.

[0165] The IVL system 100 may include a high voltage generator with a touchscreen. The high voltage generator may use AC mains to provide power to generate acoustic shockwaves without a need for repeated system charging. In some examples, the IVL system 1100 may include multiple coronary monorails and peripheral OTW balloon sizes.

[0166] In some examples, the balloon assembly of the IVL system 100 may have a diameter between 2.5-4 millimeters, although other diameters are possible. In some examples, the balloon assembly may be between 24-30 millimeters long, although other lengths are possible. The balloon may be semi -compliant and able to withstand pressures of 4 ATM to 10 ATM, but other pressures are possible. The balloon assembly may include three acoustic emitter assemblies. Each emitter assembly may include at least two emitters. In some examples, the three acoustic emitter assemblies may be controlled by three (logical) channels.

[0167] In some examples, the crossing profile may be between 0.044 and 0.047 inches. In addition, the IVL system 100 may support a 0.014 inch guidewire. In some cases, the IVL system 100 may be compatible with a 6 French guide catheter. In some examples, the IVL system 100 may be optimized for a 6 French guide extension system. The IVL system 100 may support a 200-pulse minimum activation limit. In some examples, the integrated handle and cable may remove a need for a sterile sleeve.

[0168] FIG. 2 is a details illustration of a catheter assembly 200. The catheter assembly 200 may include a generator cable, a handle assembly, a pigtail cable, a hub assembly and a ballon assembly. The generator cable may be connected to the high voltage generator (not shown here). A catheter may couple the balloon assembly to the hub assembly. In some examples, a liquid, such as a saline solution, can be introduced at the hub assembly to inflate the balloon assembly.

[0169] FIG. 3 is an example view of a distal end of the balloon assembly 300. A catheter, employing a coaxial design, includes an inner shaft (A) and an outer shaft (B), which may be coaxially apposed. The balloon assembly 300 may include a full length through-hole, or guidewire lumen (C), which is compatible with a guidewire. The balloon assembly 300 may have a working length of at least 40 cm, but can be 130 cm or longer. The balloon assembly 300 has a distal end and a proximal end, where the distal end includes a flexible, radiopaque tracking tip (D) to enable atraumatic tracking through a blood vessel or hollow organ over a guidewire which ensures that the distal end of the device does not cause injury during tracking. The balloon assembly 300 may have an outer diameter which enables tracking ofthe device through a compatible guide catheter, or through an inner diameter of a blood vessel or hollow organ. The balloon assembly may include a PTCA balloon (E) attached at the distal section, coaxially opposed to the inner and outer shafts. A plurality of radiopaque marker bands (F) indicates the usable length of the balloon. The coaxial annulus between the inner shaft and outer shaft allows for a gas or fluid media to inflate and deflate the balloon. The distal end of the outer shaft terminates coaxially to the proximal balloon leg, while the distal inner shaft continues coaxially through the center of the balloon, where the distal balloon leg is bonded to the outer surface of the inner shaft.

[0170] Located coaxially over the inner shaft, and axially within the working length of the balloon, are a plurality of acoustic emitters (G) including insulating ring mounts. These acoustic emitters (also referred to herein as emitter assemblies) provide one or more sparkgap features using emitters (H) and wire (I) that enable high energy pulses to create a short pulse width spark, when the energy is delivered to the emitter. A plurality of wire rings (J) is used to hold the wires onto the catheter shaft. A plurality of radiopaque marker bands (K) is used to hold the wires onto the catheter shaft. Typically, this high energy spark occurs at every gap feature on the emitter assembly, with each short pulse width spark creating a high frequency acoustic shockwave. A plurality of thin, small gauge insulated wires are used to deliver the energy from an external energy source, such as but not limited to outside the patient into each emitter in the catheter.

[0171] FIG. 4A shows details of the balloon assembly 400 of FIG. 1. The balloon assembly of FIG. 4 A includes three acoustic emitter assemblies, although other examples may include more or fewer acoustic emitter assemblies. In this example, the balloon assembly includes a distal, middle, and proximal acoustic emitter assembly. The balloon assembly may also include a distal tip, a distal marker, and a proximal marker. The distal and proximal markers may enable the clinician to locate the balloon assembly using fluoroscopy or the like. FIG. 4B shows a perspective view of the balloon assembly 405 of FIG. 1. FIG. 4C shows the balloon assembly of FIG. 1 inserted into a blood vessel with the balloon inflated. Additionally, one or more of the acoustic emitter assemblies may be generating pressure waves that are delivered through the balloon assembly to the blood vessel. FIG. 4D shows the balloon assembly of FIG. 1 with the balloon inflated. FIG. 5 shows an example view of the distal tip 500 of the balloon assembly of FIG. 1.

[0172] FIG. 6 shows an example acoustic emitter assembly 600. The acoustic emitter assembly 600 includes the inner shaft (A), and axially within the working length of the balloon, and acoustic emitters (G) including ring mounts. These acoustic emitter assemblies 600 can provide one or more spark-gap features using emitters (H) and a wire (I) that enablehigh energy pulses to create a short pulse width spark, when the energy is delivered to the emitters (H). FIG. 7 shows another example of an acoustic emitter assembly 700 with possible dimensions, although other sizes are possible.

[0173] FIG. 8 shows another view of a hub assembly 800. The hub assembly 800 may be an example of the hub assemblies of FIG. 1 and FIG. 2. The hub assembly 800 can include four ports, although other numbers of ports are possible. One port receives the catheter shaft assembly. Another port is employed as a balloon inflation port (M). Another port is employed as a guidewire port (N) which communicates with the guidewire lumen in the catheter assembly. Another port is employed as an electrical cable port (O). The balloon inflation port (M) communicates with the catheter annulus, to provide a means of inflating and deflating a balloon (in the balloon assembly described herein) using an inflation device such as but not limited to an inflator or a syringe. In some examples, a saline solution is used to inflate the balloon. The guidewire port (N) enables the user (clinician) to backload an interventional guidewire, such as but not limited to a .014 coronary guidewire, into the catheter guidewire lumen.

[0174] The electrical cable port (O) allows the electrical conductors coming from the catheter assembly to connect to a pigtail cable (P). The pigtail cable (P) houses the catheter conductor wires in a tubular pigtail cable housing. The cable housing is attached to the hub assembly 800.

[0175] FIG. 9 shows an example catheter handle assembly 900. The catheter handle assembly 900 can include a catheter handle (Q). The pigtail cable (P) may be coupled to the catheter handle (Q). The catheter handle (Q) acts as a housing for an internal PCB (R). The PCB (R) provides a user pushbutton (S) to initiate electronic treatments (deliver of acoustic pulses). The PCB (R) may include a programmable EEPROM which contains device information such as but not limited to device serial number, device lot number, and number of device shots. The PCB (R) also provides attachment points to connect the thin catheter conductors to thicker wires from a larger generator cable (T). This larger generator cable (T) is typically a shielded cable housing high voltage conductors, and low voltage control wires.

[0176] FIG. 10 shows an example cable assembly 1000. The cable assembly 1000 may include the catheter handle assembly 900 of FIG. 9. As shown, a generator cable (T) terminates into a multipin circular cable connector (U). This cable connector (U) mates with a panel mount jack located on the front bezel of the high voltage generator. FIG. 11 A shows another view of the catheter handle of FIG. 9. FIG. 1 IB shows the catheter handle of FIG. 9 and a view of the balloon assembly of FIG. 3. FIG. 12 shows example packaging for shipment of the cable assembly of FIG. 10.

[0177] Notably, any of the catheters or balloon assemblies described herein are capable of traversing hollow anatomy such as but not limited to blood vessels. The catheters or the balloon assemblies may include a distal and proximal end, and a typically tubular main body. Any of the systems or devices described herein can include a central guidewire lumen, to enable the catheter to traverse over a guidewire. Any of the systems or devices described herein can include a distally located coaxial PTCA balloon element, to enable balloon dilatation of a hollow body organ. The working length of the balloon is indicated using a plurality of fluoroscopic markers located on the catheter inner shaft. Any of the systems or devices described herein can include a full-length inflation lumen, in the form of an annulus that runs from the balloon to an inflation port. In addition, the systems or device may include a plurality of coaxial ring mounts, radiopaque marker bands, and wire rings, located within the balloon or balloon assembly and attached to the catheter inner shaft. The ring mounts and wire rings may include a short axial length to enhance catheter lateral flexibility and trackability. In some examples, the ring mounts can provide mounting locations for a plurality of paired emitter elements (acoustic emitters). Individually interconnected acoustic emitters may be connected via “S” or “C” patterned conductors to facilitate ease of assembly and lower profile. The ring mounts may provide separated channels to enable separation of catheter conductors as they pass through each ring element. Separate channels enable the user to select which emitters to fire, and in which selectable sequence, as well as single channel only. In addition, the ring mounts described herein may provide a means of holding down the wires onto the catheter shaft. In some examples, the wire rings may provide a means of holding down the wires onto the catheter shaft.

[0178] In some examples, the radiopaque marker bands which are attached coaxially to the catheter shaft, providing a means of fluoroscopically indicating the working length of the balloon. The radiopaque marker bands may be made of a hard metal such as but not limited to 304ss. This hard metal advantageously enables robustness to the design and longer emitter life.

[0179] In some examples, emitter elements may be attached to thin electrical conductors. These are typically but not limited to solid core copper insulated with polyimide. The emitter elements may be spaced typically 0.007” apart to form a spark gap feature. This gap distance may be controlled by the ring mount aperture. Some ring mounts may provide a typically parabolic aperture opening over each spark gap which is typically aligned vertically above the spark gap feature. The aperture may provide an acoustic amplification of the shock (acoustic) wave.

[0180] Any of the parabolic apertures described herein may provide a means of shaping and directing the acoustic shock created by the spark to emanate outwards away from the spark gap. The directionality of the parabolic apertures may enable the user to focus and aim the shock wave in any particular direction.

[0181] Any of the catheters or balloon assemblies described herein may include a hub assembly. In some examples, the hub assembly may include four ports. The hub assembly may include a catheter port, a guidewire port, an electrical cable port, a balloon inflation port, and a pressure sensor. The catheter port may couple to any feasible catheter. The guidewire port may allow a guidewire to pass through the hub assembly and into the catheter guidewire lumen. The electrical cable port may enable the attaching of a pigtail cable to the hub assembly, allowing electrical conductors to pass from the catheter to the pigtail cable. The balloon inflation port can provide a means of inflating and deflating of the balloon (of the balloon assembly) via an inflation lumen. The pressure sensor may enable the monitoring of balloon pressure during treatment and using balloon pressure as a means of determining treatment progress. In some examples, the pigtail cable enables conductors from the catheter and the hub assembly to attach and / or couple to a handle. The handle may house or include a printed circuit board and / or a push button. The printed circuit board may provide a means of connecting pigtail electrical conductors into conductors in a generator cable. Both the pigtail cable and generator cable may be coupled or attached to the handle. The push button can enable the user to initiate the treatment from the generator to the catheter. The push button may also provide additional functionality, based on the number of consecutive presses, such as but not limited to treatment stop, treatment length, or treatment sequence. In some examples, the pigtail cable and the generator cable may be designed for single use and are disposable after use. The benefit of any attached cables includes, but is not limited to ease of use, pre-sterilized ready for use, no need to locate prior to procedure, no need for a sterile sleeve or sock, and reliable electrical connection.

[0182] FIG. 13 shows other example views of the IVL system of FIG. 1. FIG. 14 shows an example view of packaging of one or more parts of the IVL system of FIG. 1.Operation

[0183] During typical use, the distal end of the device may be positioned coaxially inside of a calcified lesion, such as but not limited to a calcified blood vessel. The balloon may be sized such that it is slightly larger than the target vessel natural lumen. The balloon may be inflated inside of the calcified lesion to a low pressure, such as but not limited to 4.0 ATM. This pressure may help provide intimate contact between the device and the calcified lesion. The balloon may be inflated with, but not limited to, saline. Once inflated, a short pulse(typically but not limited to 1.0 us) of high voltage energy (typically but not limited to 3,000 volts DC) is applied to the emitter spark-gap. The energy then creates a spark across the gap, along with a powerful (typically but not limited to 5.0 MPa) shock wave. This pressure wave propagates outwards through the saline in the balloon, and through the wall of the balloon. The pressure wave continues into the surrounding vessel tissue. Because of the frequency of the pulse width of the wave (typically but not limited to l.OMhz), the pressure energy resonates with any hard materials in the surrounding vessel wall. Since calcium is a hard, rigid material, the pressure wave impacts the hard calcium, causing the hard calcium to fracture after one or more shocks. Once the calcium is sufficiently fractured, such that the vessel can be dilated, energy delivery is discontinued, and the balloon may be inflated to a higher pressure until the vessel reaches its native inner diameter.Catheter

[0184] In any of these examples the catheter may consist of a plurality of tubular members, including an inner member shaft having a lumen suitable for a guidewire, a radiopaque atraumatic tip, and an outer diameter which would fit coaxially inside of an outer member shaft. An example of an inner member would have a 0.017” inner diameter, and a 0.021” outer diameter, with a length of about 145 cm, and a distal tip loaded with a tungsten additive for radiopacity.

[0185] The inner member may be coaxially apposed inside of an outer member shaft. The inner diameter of the outer member shaft may have an inner diameter which may fit the inner member shaft, along with a plurality of electrically conductive, insulated wires. An example of an outer member would have a 0.042” inner diameter to fit the inner member shaft and (4) conductors, and an outer diameter of 0.048”, with a length of 100cm.

[0186] The balloon may be located distally. The balloon may be coaxial to both the inner member shaft and the outer member shaft. An example of the balloon would have an outer diameter of 4.0mm, a working length of 30mm, and a nominal pressure of 10.0 ATM with a rated burst pressure of 18.0 ATM, and is made of PET. The distal end of the balloon is bonded to the outer diameter of the inner member shaft. The proximal end of the balloon is bonded to the outer diameter of the outer member shaft. The annular space between the inner member and the outer member is used as an inflation / deflation passageway to inflate and deflate the balloon. Additionally, this annular space is used to house the electrical wires which connect the emitter assemblies to the generator.

[0187] A plurality of acoustic emitters (e.g., emitter assemblies) may be located coaxially on the outside of the distal inner member shaft, within the working length of the balloon. The assemblies are axially spaced along the length of the balloon. Conductive wires are connectedto the emitter assemblies and run along the catheter shafts inside of the outer member shaft, and back through a Y-arm hub and into a handle.

[0188] The handle may house a PC board, e.g., forming the control circuit. The board has a plurality of traces, which allow the electrical connection between the emitter conductors and the catheter generator cable conductors. The handle also houses a button which enables the user to initiate electrical treatments. The handle is connected to a catheter cable and a generator cable.

[0189] The catheter cable houses the electrically conductive, insulated wires that connect the emitter assemblies to the generator. An example of the catheter cable would be a 0.063” x 0.100” PVC tube that is 24” long.

[0190] The generator cable may also house the electrically conductive, insulated wires that connect the emitter assemblies to the generator. It also houses a plurality of wires that connect a momentary button and a thermocouple sensor to the generator. An example of the catheter cable would be a .150” OD, shielded PVC jacket that houses (4) shielded high voltage wires and (4) shielded low voltage wires, which is 8.0 feet long. This cable terminates into a multipin circular cable connector. This cable connector mates with a panel mount jack on the generator.High Voltage Generator

[0191] The generator has a chassis, which houses various electronic circuit boards and power supplies, a display, and connectors. The various electronic circuit boards enable the generator to generate and control high voltage, which is used to power the emitters, and also control the voltage settings and control the therapy used to treat the patient.

[0192] A typical embodiment of the generator consists of a chassis that houses various electronic components. This would include but is not limited to power supplies, high voltage boards, main control boards, switching boards and voltage regulator boards. Externally, the chassis would include but are not limited to an AC power input module, a main power button, a multipin connector for the catheter, and a touchscreen control LCD display screen.

[0193] The generator can be powered from AC voltage using a power cord, or DC with internal batteries.

[0194] The generator also uses embedded control software, used to control the generator outputs to the catheter. The software would include but is not limited to functions to control voltage level, pulse width, emitter selection, treatment sequence type, and start / stop controls.Emitter function

[0195] The design of the emitter assembly provides a plurality of spark-gap features, from which high energy can flow across, creating a short pulse spark. The electric spark is an abrupt electrical discharge that occurs when a sufficiently high electric field creates an ionized, electrically conductive channel through a normally insulating medium, often air or other gases or gas mixtures. As the spark dissipates, the rapid transition from a nonconducting to a conductive state produces a brief emission of light and a sharp crack or snapping sound. The spark is an electrical current flowing through a small amount of ionized air or water (plasma). The very hot plasma expands rapidly, producing a pressure wave similar to a very small explosion.

[0196] A spark is created when the applied electric field energy exceeds the dielectric breakdown strength of the intervening medium. For air, the breakdown strength is about 30 kV / cm at sea level. At the beginning stages, free electrons in the gap by the electrical field. As they collide with air molecules, they create additional ions and newly freed electrons which are also accelerated. At some point, thermal energy will provide a much greater source of ions.

[0197] The exponentially increasing electrons and ions rapidly cause regions of the air in the gap to become electrically conductive in a process called dielectric breakdown. Once the gap breaks down, current flow is limited by the available charge of high energy. If the power supply continues to supply current, the spark will evolve into a continuous discharge called an electric arc. An electric spark can also occur within insulating liquids or solids, but with different breakdown mechanisms from sparks in gases.

[0198] As the spark dissipates, the rapid transition from a non-conducting to a conductive state produces a brief emission of light and a sharp crack or snapping sound. This snapping sound creates a high-velocity sound wave, which propagates away from the spark-gap, through whatever surrounding gas or fluid media is around the emitter.

[0199] The emitters are housed in a novel ring mount. This ring mount provides several benefits to the invention, including but not limited to controlling the emitter alignment, controlling the emitter gap, controlling the path of the conductors, providing a parabolic funnel aperture to amplify and guide the shock wave, providing ease of assembly in a small profile, and reducing production costs associated with labor and inspection hours.Emitter / Acoustic pressure function

[0200] First, it may be expected to see an expansion pulse (the first shockwave, as the bubble reaches max radius of expansion). The electrode gap may be broken down at T=0, the voltage across the electrode gap drops violently due to extremely low resistance of a plasmachannel created between the electrodes which is full of high -temperature and high-pressure plasma. The plasma channel may expand rapidly and compress the surrounding water to create the first shockwave (expansion pulse). After reaching its peak, the shockwave may decrease somewhat, according to an exponential law (thus resulting in the observed decay shape of the pulse).

[0201] The signal may then potentially include a negative reflection signal from the tank. For example, a second bubble pulse (representing the bubble collapse), e.g., at the moment the bubble stops collapsing the pressure goes to its peak again. In some cases a negative reflection signal may result in this bubble collapsing. Then, this procedure may be repeated for a third, fourth or more bubble expansion / collapses until complete energy depletion. From this data, the second pulse (the collapse pulse) actually had a larger peak pressure than the initial expansion pulse (the first pulse may be chosen as the be most reliable and the user or apparatus could shut off the electrical pulse quickly to try to prevent subsequent pulses / bubble collapses in order to be most reliable and preserve electrode material).Emitter Design Details

[0202] The device emitter assembly is the primary feature that enables the device to generate spark-induced shock waves. The design generally provides one or more spark-gaps, across which high energy creates the spark.

[0203] There are several characteristics of emitter design that can positively or negatively affect the effectiveness and durability of the emitter. These include but are not limited to emitter material, emitter gap size, and emitter gap aperture shape.

[0204] Emitter material directly affects the durability of the emitter spark gap. Because the spark exposes the emitter material to high temperature, soft metals tend to melt and deform after several sparks. These can include, but are not limited to copper, aluminum, and platinum / Iridium. The ideal emitter materials are typically very hard, and include but are not limited to stainless steel, tool steel, and tungsten carbide.

[0205] Emitter gap size affects the size and shape of the spark being created. Depending on the dielectric breakdown strength of the saline in the balloon and the voltage level of the energy being delivered, the gap size must be small enough to enable the spark to form across the gap. Generally speaking, for a given voltage energy level and saline dielectric breakdown strength, there will be a minimum gap required to allow a spark to form.

[0206] Emitter gap shape affects how the spark forms and forms across the gap. Typically, the spark will focus on and favor sharp edges and corners. Smooth surfaces and rounded edges prevent “focal spark patterns” which tend to focus spark energy in a small area, accelerating emitter degradation in that area. The gap shape is typically aligned with anaperture which focuses the shock energy and directs this energy towards the calcium. By optimizing the shape of the aperture, the energy can be amplified and directed to provide the optimal treatment.Emitter EmbodimentsCircular Emitter

[0207] One embodiment for a catheter emitter consists of a plurality of flat emitters. Each emitter consists of components which create a spark gap, from which an electrical spark is enabled to form.

[0208] FIG. 15 shows an example circular emitter 1500. In this embodiment, there is a catheter shaft (A) onto which there are two crimped emitter conductors (B). Crimped to each emitter conductor is a positive wire (C), and a negative wire (D) one wire for each conductor. Over each of the conductors is a nonconductive polyimide sleeve (E), which fits over all the conductors and is coaxial to the catheter shaft. The sleeve has a hole (F) which is aligned over each conductor. Over the sleeve is a stainless-steel ring (G). The ring has holes over each hole in the sleeve. The holes in the ring are typically larger than the holes in the sleeve. In this embodiment, the spark jumps radially from the inner emitter, through the hole in the polyimide sleeve, and outwards to the exposed metal ring.Flat Spark Plug Gap Emitter

[0209] Another embodiment consists of a plurality of flat emitters. Each emitter consists of components which create a spark gap, from which an electrical spark is enabled to form. FIG. 16 shows an example spark plug gap emitter 1600. In this embodiment, there is a catheter shaft (A) onto which there are four crimped emitter conductors (B). Crimped to two of the emitter conductors is a wire, one positive wire (C) and one negative wire (D) for each conductor. Two other conductors (E) have a wire (F) connecting them together. Over each of the conductors is a nonconductive polyimide sleeve (G), which fits over all the conductors and is coaxial to the catheter shaft. The sleeve has a slot (H) which is aligned over each pair of conductors. In this embodiment, the spark jumps from one emitter, across the gap axially to the next closest emitter, through the jumper to the next emitter, then across the next gap. Circular Emitter

[0210] Another embodiment consists of a plurality of coaxially located stainless steel rings. Each emitter consists of components which create a spark gap, from which an electrical spark is enabled to form. FIG. 17 shows an example circular emitter 1700. In this embodiment, there is a catheter shaft (A) onto which there are two cylindrical emitter conductors (B). Attached to each emitter conductor is a positive wire (C), and a negative wire(D) one wire for each conductor. In this embodiment, the spark jumps axially from the edge of one ring, across the gap to the next closest ring edge.Ring Mount

[0211] The invention typically requires a plurality of emitters and wires to be attached to the outer diameter of a catheter shaft, which is typically tubular in shape. The location and positioning of said emitters is critical to the function of the design, which requires a spark gap in order to create a spark.

[0212] To facilitate assembly and positioning of said emitters and wires, a concept for a positioning ring is described here.

[0213] A tubular structure, having an inner diameter with features, and an outer diameter with features, is designed to fit coaxially over an inner member catheter shaft.

[0214] The inner diameter features include typically rectangular slots or pockets, which can accommodate emitter conductor components. The shape and size of the rectangular features provides a means of automatically positioning the emitter conductors in the correct orientation and location, to ensure that the gap between the emitter conductors is correct and repeatable.

[0215] The outer diameter features include a plurality of slots or holes, which are aligned with the gap formed between the emitter conductors. These slots or holes allow the spark created at each gap to emanate outwards, allowing the acoustic energy from the spark to diverge away from the gap. The ring ensures that the slots or holes are always aligned with the emitter conductor gaps.

[0216] Use of the ring in emitter assembly facilitates ease of assembly, due to the features provided by the ring, which aligns the various components in an optimal setting for best performance. The ring also enables the assembler to build the emitter assembly separate from the catheter, such that pre-assembled emitter rings can be built ahead of time and stored in inventory, ready for use in a full catheter once needed.

[0217] FIG. 18 shows an example of a ring mount 1800. FIG. 19 shows a view 1900 of the example ring mount of FIG. 18 disposed on a catheter. In this embodiment, the ring mount (A) is mounted coaxially on a catheter shaft (B). A plurality of emitters (C) are mounted into slots in the ring mount. The ring mount enables consistent, even alignment of the emitters. Note the slotted aperture (D) that enables shock waves to emanate from the spark. The ring mount also provides channels (E) to allow wires to pass axially through the ring mount from adjacent rings. FIG. 20 shows another view 2000 of the ring mount disposed on a catheter.

[0218] FIG. 21 shows a ring mount 2100. The design allows for round cylindrical emitters instead of flat emitters. This can enable smaller profile catheters to be made. Slotted aperture shown here.

[0219] FIG. 22. shows another ring mount 2200. The design allows for the emitters to be mounted side by side, perpendicular to the shaft axis. This can enable smaller profile catheters to be made. Also note the oval shaped aperture with angled walls which can focus and enhance the shock wave. Individual separators keep conductors from touching and isolate the emitters from the conductors.

[0220] FIG. 23 shows another example ring mount 2300. The design allows for the emitters to be mounted side by side, perpendicular to the shaft axis. This can enable smaller profile catheters to be made. Also note the oval shaped aperture which can focus and enhance the shock wave. Individual separators keep conductors from touching and isolating the emitters from the conductors. This embodiment also employs a floor feature under the aperture, to guide the shock wave energy outwards away from the catheter shaft.

[0221] FIG. 24 shows a ring mount 2400. The design allows for the emitters to be mounted side by side, perpendicular to the shaft axis. This can enable smaller profile catheters to be made. Also note the round shaped aperture which can focus and enhance the shock wave. Individual separators keep conductors from touching and isolating the emitters from the conductors. This embodiment also employs a floor feature under the aperture, to guide the shock wave energy outwards away from the catheter shaft.

[0222] FIG. 25 shows an assembly 2500 with example ring mounts. FIG. 26 shows a view of a center ring assembly 2600. FIG. 27 shows a center ring assembly 2700 without a ring mount.Ring mount / Emitter Aperture / Acoustic Amplifier

[0223] The spark gap provides a feature that enables a high voltage to jump across, causing a high frequency spark to occur. This spark creates an acoustic shock wave which can fracture calcification on blood vessels.

[0224] The nature of the wave shape and intensity can be affected by the shape of the surrounding geometry near the spark. The wave energy typically reflects off surrounding surfaces as it emanates away from the gap in all directions. This acts as an acoustic amplifier.

[0225] FIG. 28 shows an example open spark gap with no surrounding reflective surfaces 2800. Due to the rapid divergence, the wave energy dissipates rapidly for a given distance from the source gap. Ideally, the wave energy should reach the target calcification with minimal loss.

[0226] FIG. 29 shows an example spark gap with reflective surfaces. Due to circular surround, the wave energy dissipates less rapidly for a given distance from the source gap. Ideally, the wave energy should reach the target calcification with minimal loss.

[0227] FIG. 30 shows an example spark gap 3000 with shallow waveguide aperture. Due to circular surround combined with a deeper, narrower opening, the wave energy is much more focused with minimal dissipation for a given distance from the source gap. This reduces the amount of energy loss as the wave reaches the target calcification.

[0228] FIG. 31 shows an example spark gap 3100 with a deep waveguide aperture. Due to circular surround combined with a deeper, narrower opening, the wave energy is much more focused with minimal dissipation for a given distance from the source gap. This reduces the amount of energy loss as the wave reaches the target calcification.

[0229] An aperture design includes three characteristics: aperture hole diameter, spark gap, and floor thickness / aperture depth. The aperture is meant to form and guide the acoustic wave created by the spark and bubble to attain the most efficient wave output, in MPa.

[0230] FIG. 32 shows an aperture design 3200 with no floor. FIG. 33 shows an aperture design 3300. The aperture design 3300 includes a floor to facilitate 3D printing. By adding a floor, the aperture now had a "depth" element to control the volume of the aperture. In audio acoustics, the shape and depth of an aperture can significantly shape the direction and strength of a sound wave. Typically, the deeper and narrower the aperture, the more powerful the acoustic wave. This also makes the wave more directional, and travel farther. The effective output generally mirrors the shape of the aperture.

[0231] FIG. 34A shows an example aperture 3400 with a shallow aperture. FIG. 34B shows an example aperture 3410 with a deep aperture. FIG. 35 A shows a ring mount 3500 with a thicker floor thickness. FIG. 35B shows a ring mount 3510 with a wider hole. FIG. 36 shows a side view of a ring mount 3600 with a feature to control a spark gap between emitter elements. FIG. 37 shows a table 3700 of ring mount characteristics and associated profiles 3710.

[0232] FIG. 38A shows a view 3800 of a ring mount disposed on a catheter. FIG. 38B shows a side view of the ring mount 3810. As shown, a feature of the ring mount may control the spark gap, or distance between emitter elements.

[0233] FIG. 39A shows a skeleton view of a ring mount assembly 3900. A voltage can come into the ring mount assembly 3900 to a first emitter. In FIG 39B, a voltage jumps from the first emitter to a second emitter. The spark causes a bubble to form and collapse and generate an acoustic wave or shock. In FIG. 39C, voltage may pass from the second emitter through an “S” jumper wire to a third emitter. In FIG. 39D, the voltage may pass from thethird emitter to the fourth emitter and create another spark. This spark may also generate an acoustic wave or shock. In FIG 39E, voltage passes through the fourth emitter and to the generator. In some cases, the voltage goes to ground. FIG. 39F shows acoustic waves emanating from apertures in the ring mount.

[0234] FIG. 40 shows an example assembly 4000 that includes three ring emitters disposed on a catheter. The apertures of the ring emitters may be disposed to directionally distribute shock waves around the catheter.

[0235] FIG. 41 is a schematic diagram of a ring mount assembly 4100. The example ring mount assembly 4100 may include four emitters (shown as four squares). In some implementation, a single ring mount assembly 4100 may be associated with a single, independent channel.

[0236] FIG. 42A shows an example catheter assembly 4200 with three ring mount assemblies. The ring mount assemblies may include distal, middle (or center), and proximal ring mount assemblies. Each ring mount assembly may be associated with a separate channel. FIG. 42B shows the catheter assembly 4200 configured for three channel control.

[0237] For example, in FIGS. 42A (and shown in at least two of the examples of FIG. 44, e.g., 2R2Ch and 3R2Ch) the apparatus may be configured to provide individual connections to each acoustic emitter. For example, the apparatus may include a plurality of acoustic emitters attached to the elongate catheter body within the inflatable balloon, wherein acoustic emitter comprises an electrically insulating ring mount, each coupled to an individual channel (e.g., Chi, Ch2, Ch3). Each ring mount may include a first emitter pair 4201 comprising a first pair of electrodes 4203, 4205, a second emitter pair comprising a second pair of electrodes 4207, 4209, and a first spark aperture (not shown) that may be formed through a surface of the ring mount that is radially outward of and between the first pair of electrodes. A second spark aperture may be formed through the surface of the ring mount and may be radially outward of and between the second pair of electrodes. The spark gap region is formed between the two electrodes, e.g., each spark aperture may form a spark gap region. The apparatus may also include a control circuit 4215 configured to control the application of electrical energy to each of the acoustic emitters. As shown in FIG. 42B, the apparatus may also include an independently addressable electrical line 4213, 4217, 4219 extending proximally to the control circuit from a first electrode of the first pair of electrodes of each of the acoustic emitters. The second electrode 4205 of the first pair of electrodes is electrically coupled to a first electrode 4207 of the second pair of electrodes of each of the acoustic emitters. A second electrode 4209, 4209’, 4209” of the second pair of electrodes of each ofthe acoustic emitters is shown electrically coupled to a common electrical return line 4211 extending proximally to the control circuit.

[0238] FIG. 43 shows a view 4300 of the ring mount assemblies of FIG. 42B. In particular the view 4300 shows possible cable or conductor wiring routing. FIG. 44 shows example wiring implementations 4400 of various ring mount configurations.

[0239] FIG. 45 shows a wiring diagram 4500 that may be used to implement a three-ring mount assembly. FIG. 46A shows a first view of a wiring implementation of the wiring diagram of FIG. 45. FIG. 46B shows a second view of the wiring implementation of the wiring diagram of FIG. 45. In FIG. 46B, the catheter is rotated with respect to FIG. 46A. FIG. 47 shows example “C” and “S” cable interconnections. These cable interconnections can be external to the ring mount. FIG. 48 shows an example C cable interconnection.

[0240] FIG. 49 shows an example ring mount 4900 with internal electrical interconnections. The ring mount 4900 may include a solid metallic and / or conductive element that replaces any feasible external wires.

[0241] FIG. 50 shows a view of the balloon assembly 5000. Notably, elements of the ring mount assemblies should fit within an inner diameter of the catheter.

[0242] FIG. 51 shows a view of a ring mount disposed on a catheter. FIG. 52 shows a view of multiple ring mount assemblies disposed of a catheter. Notably, in some examples, the catheter may move independently of the balloon, providing another degree of positioning of the ring mount assemblies with respect to the patient.

[0243] For example, FIG. 53 shows a balloon assembly 5300 of an IVL system. The balloon assembly 5300 may be expanded and disposed in a blood vessel that includes calcium deposits. For example, a large nodal calcium deposit may be located proximally with respect to the balloon assembly. However, as shown in FIG. 53, the ring mounts may not be close to the nodal calcium deposit.

[0244] In FIG. 54, shows the ring mounts repositioned with respect to the blood vessel. For example, the catheter may move (in this example, proximally) with respect to the balloon. The clinician may move the catheter to align at least one of the ring mounts (and the associated emitters) with the nodal calcium. FIG. 55 shows a proximal ring mount assembly delivering sonic pulses toward the nodal calcium deposit.

[0245] As discussed herein, a ring mount may include an aperture that can direct, focus, and / or amplify sonic or acoustic energy from emitters toward a portion of the blood vessel. Similar to as described with respect to FIGS. 53-55, the ring mount may be rotated to further direct energy toward a particular portion of the blood vessel.

[0246] For example, FIG. 56 shows how the catheter may be rotated thereby directing apertures of any ring mount assemblies toward a particular location of the blood vessel. In some cases, any of the apertures may be directed toward nodal calcium deposits. FIG. 57 shows sonic or acoustic waves radiating from a ring mount toward a nodal calcium deposit.

[0247] To assist in locating, positioning, and / or aligning a ring mount assembly within a patient, a radiopaque marker may be included on the ring mount. FIG. 58 A shows an example ring mount 5800 that includes a radiopaque marker. In the example of FIG. 58 A, the radiopaque marker may be an “L” shaped marker formed from radiopaque ink. There may be a predetermined relationship between the radiopaque marker and any aperture included in the ring mount. FIG. 58B shows the ring mount 5800 in a first position. In this first position, the apertures are pointed upward and downward, particularly with respect to the radiopaque marker.

[0248] FIG. 58C shows the ring mount 5800 in a second position. In this second position the radiopaque marker may face downward while the apertures face into and out of the page. FIG. 58D shows the ring mount 5800 rotated so that the radiopaque marker faces into the page. The apertures may face upward and downward. In FIG. 58E, the ring mount is rotated such that the radiopaque marker faces upward while the apertures face into and out of the page.High voltage generator design

[0249] The design of the high voltage generator may provide a means of controlling the electrical high energy pulses, which enable high energy pulses to create a short pulse width spark, when the energy is delivered to the emitter. Typically, this high energy spark occurs at every gap feature on the emitter assembly, with each short pulse width spark creating a high frequency acoustic shockwave.

[0250] The high voltage generator is typically a self-contained chassis, which houses electronic hardware used to generate and control the electrical energy used to provide power to the catheter. The chassis design employs a novel removeable insert assembly, which allows access to the various electrical boards. The insert can be separated into two or more sections, with each section acting as mounting locations for the internal boards and components. The design employs a rear shell, into which the insert assembly slides into. An angled front bezel captures the insert assembly and attaches it to the shell to lock the assembly together. The front bezel houses a touch screen for user interface, and a panel mount multipinjack to connect the catheter cable to the generator. The shell houses an AC input module and a main on / off switch as well as an SD card slot.

[0251] A high voltage generator may include a main board, a high voltage switchboard, and a high voltage board.

[0252] The main board may include a 32-bit processor. In some examples, the 32-bit processor may include a PIC32MZ2048EMF144 running at 200MHz. In some examples, the processor may control:

[0253] A TFT 2.8” display 320x240px communicates with the processor via fast (50MHz) SPI channel. The display is equipped with a resistive touch screen also communicating with the main processor. The brightness of the display is controlled by the PWM signal generated by one of the Output Compare (OC) modules in the main processor.

[0254] One or more flash memory chips (each 16MB) allow for storage internal data of the system. The flash chips communicate with the main processor via fast (50 MHz) SQI channel.

[0255] An SD card interface to communicate via an SPI channel.

[0256] A real time clock and calendar (RTC) that may be implemented as a separate, battery backed-up chip communicating with the main processor via I2C channel. The RTC may support the SD card file system.

[0257] A sound system that supports simple, square wave-based sound of adjustable volume. The sound is generated by the OC module. The volume is adjusted by the electronic potentiometer configured as a divider of the signal generated by the main processor. The sound signal is subsequently amplified by the Iwatt audio amplifier which drives a speaker.

[0258] An interface with an adjustable high voltage power supply. The high voltage power supply provides high voltage to the catheter emitters. The interface consists of two signals: a high voltage enable / disable signal and a high voltage amplitude adjustment signal. The enable / disable signal may be implemented as analog signal 0V-3 V in magnitude corresponding to 1.5kV-4kV high voltage range. The analog signal is generated in an external DAC communicating with the main processor via the SPI channel.

[0259] An interface with high voltage switches may support a high voltage channel selection (demultiplexer). The pulse generating the spark is generated in the dedicated OC peripheral of the main processor. This signal is routed to the high voltage switches. The demultiplexer reroutes the pulse signal to the selected high voltage switches. In addition, the interface may support a high voltage configuration detection. There may be up to four high voltage switches installed in the system. The interface enables identification of high voltage channels that may be equipped with the switches (i.e., which are functional).

[0260] A 1-wire and Pushbutton interface. The information necessary for identifying the parameters of the catheter connected to the system is stored in the 1-wire eeprom located inthe catheter. The interface provides means of communication with the eeprom and detection of the press of the pushbutton located in the catheter.

[0261] Power supply: The main board is powered by 12V medical grade switching power module. 12V is used directly to power High Voltage Switches and High Voltage Board. The 3.3 V used for powering electronics of the Main Board is generated in a two-stage voltage regulator. The first stage consists of the switching regulator regulating 12V down to 4V; the switching configuration provides high efficiency at the cost of an increased noise level. The second stage, an LDO, regulates 4V down to 3.3V; linear configuration provides good noise level, while the power dissipated in the chip is small because of low voltage drop-out.

[0262] The high voltage switch can operate with voltages up to 4.7kV. It is galvanically isolated from the power and drives voltages with a 5kV isolation barrier. The switch is designed to work in either low side or high side configuration (for flexibility). The switch is powered from 12V which is converted into galvanically isolated 12V interval voltage in a DC / DC converter. The internal voltage is regulated down to 10V (to lower the noise level of the voltage generated by the DC / DC converter) and used for powering the MOSFET driver. The switch is driven by the signal from the main processor separated by the optocoupler. The secondary side of the optocoupler is powered from the 5 V voltage derived from internal 10V voltage. The secondary side of the optocoupler drives the MOSFET driver.

[0263] The MOSFET driver output signal drives the gate of the high voltage MOSFET. Since the high voltage MOSFET is “floating”, it is possible to configure it either as a low side switch or as a high side switch. The high voltage switch can respond to pulses as short as approximately 600ns.

[0264] The high voltage board may be designed to generate adjustable high voltage DC varying from 1.5kV to 4kV. It is galvanically isolated from the power and drives voltages. The voltage is generated by a programmable PWM controller driving five galvanically isolated custom-made transformers, each capable of generating 800V max. The primary side signal is used as a feedback voltage which simplifies the design at cost of poorer controlling the impact of the load on the high voltage side.

[0265] The high voltage is adjusted by changing the analog signal 0V-3 V. The signal is injected into the PWM controller feedback loop causing the change of the amplitude of the signal driving the primary winding of the transformers. The voltage on the secondary winding can vary from 300Vpeak to 800Vpeak.

[0266] The secondary windings of the transformers are connected to the rectifiers in series, so the total voltage at the output can be adjusted from 1.5kV to 4kV. The PWM signal can be disabled so the output voltage is 0V.Generator software

[0267] The software is written in C++ and compiled with Microchip XC-32 compiler, although other languages and compilers are feasible. The software consists of several objects (classes), each servicing subsystems or processes of the device. The set of classes in the code may be divided into two sections: A generic set of classes based on libraries servicing typical set of peripherals of the microcontroller, such as: display, touch screen, internal flash memory, sound system, SD card, real time clock and calendar, etc. A set of classes dedicated to supporting IVL related processes.

[0268] One process may be related to high voltage pulse generation. The pulse is generated in the Output Compare processor peripheral working in the dual compare mode generating single pulse. The clock speed (200MHz) allows for achieving 10ns pulse length resolution. The minimum pulse time length is 20ns, the maximum pulse time length was limited to 65.5ps for practical reasons. The generated pulse is routed to one (or more) of the high voltage switches by the demultiplexer. The high voltage is set by adjusting the voltage controlling the high voltage board. The adjustment range is 1.5kV-4kV.

[0269] The system described above allows for generating a high voltage pulse (or a series of high voltage pulses) of various amplitudes and lengths, thus optimizing the IVL process. The system allows the generation of a sequence of pulses sent to different emitters (if the IVL catheter consists of more than one set of emitters) to improve the results of the procedure.

[0270] Another process may be related to catheter identification. The information necessary for identifying the parameters of the catheter connected to the system is stored in the 1-wire eeprom memory located in the catheter. While the libraries supporting communication with the eeprom are standard, the structure of the data set stored in the eeprom memory is unique to the IVL process and proprietary.

[0271] FIG. 59 is a block diagram of an example high voltage power supply 5900. The high voltage generator can generate high voltage in the range 1.5kV-4kV. The high voltage side of the module is galvanically separated from the low voltage side (for safety reasons), and the blue line in the picture of the galvanic isolation indicates galvanic isolation.

[0272] The current limiting resistor (Rl) can protect the high voltage generator’s output against short circuits by reducing short circuit current.

[0273] The capacitor tank circuit (Cl) may be charged by the high voltage generator thus storing the energy. The energy stored in the capacitor depends on the capacitance C and voltage V, and is equal to A • C • V2'

[0274] The electronic switch is a low resistance high voltage switch fast floating switch. It is controlled by a microcontroller. The high voltage side of the module is galvanicallyseparated from the low voltage side (for safety reasons), The blue line in the picture of the galvanic isolation indicates galvanic isolation.

[0275] The spark gap is located in the balloon assembly of the IVL system.

[0276] In some examples, after the capacitor Cl is charged, the switch SI is shorted causing a rapid discharge through the spark gap. Since the switch may be shorted for a period of time ranging from a fraction of a microsecond to (theoretically) infinity, it is possible to control the amount of energy dissipated in the spark gap into the calcified wall of the vessel by adjusting the time during which the switch is closed.

[0277] It is important to note that many electronic switches can be connected to the same high voltage generator. They are driven independently, allowing for generating many sparks in many spark gaps. This way a sequence of sparks can be generated along the balloon allowing for more efficient treatment.

[0278] In some examples, the high voltage generator provides high-energy, short pulses to a catheter. The high voltage generator includes the ability to vary the voltage level of the energy pulses from 1.5kV to 4kV or more. Furthermore, the high voltage generator may have the ability to vary the pulse width of the energy pulses from 600ns to 65.6us or longer.

[0279] The high voltage generator may control four or more independent channels (emitter pairs). In some cases, the high voltage generator may control independent channels with a variety of sequence patterns. In some examples, a specific channel may be selected to output particular sequence patterns. In some cases, the high voltage generator can have a standard output and a high output.

[0280] In some examples, the high voltage generator may include a touch screen that can be a user interface with which the user can control the IVL system. FIG. 60 shows example screens. A first screen can be a home screen. A finger touch may transition to the ready screen.

[0281] The ready screen can become active once a catheter is plugged in. The user can touch P, M, or D and the background oval and turn it on or off if that emitter is selected. By default, all three positions may be initially selected. Click tones may inform the user when a touch has been made.

[0282] In an R&D mode, we can touch the power text to change the settings and the 10s delay text. In the commercial mode, the power text is fixed / static, or we can decide not to display at all. In the commercial mode, the 10s delay text is white and not selectable or changeable.

[0283] The top total count text 300 is default white and never changes. The bottom remaining count is colored (e.g., green) for the first 150 counts, yellow for the next 100 counts, and red for the last 50 counts.

[0284] Anything that is white on this screen is not selectable, anything that is colored can be selected except for the bottom remining counts which are not selectable, only displayed. However, in R&D mode, the power text and the 10s delay text will change color (e.g., to green) and can be selected / changed and the top total count number as well.

[0285] In the IVL treatment screen, the previously selected emitters from the IVL ready screen are highlighted in sequence from proximal to distal with each pulse repeating or actually probably needs to be asynchronous from the actual pulses since they are so short, just to indicate treatment being performed.

[0286] Treatment tones play during treatment again asynchronous from the actual pulses (Ding / Dong / Ding / Dong) .

[0287] The counter counts down again could probably be asynchronous with the pulses since they will be happening so fast, but when treatment stops the correct remaining pulses are displayed when transitioned back to the IVL ready screen. The text color is colored (e.g., green) for the first 150 pulses, yellow for the next 100 pulses, and red for the last 50 pulses.

[0288] The delay screen may be transitioned after every 10 pulses. A ten second countdown timer is displayed with text below and once done transition back to the IVL ready screen prior to being allowed to start another treatment cycle. A countdown tone may be played.

[0289] In some variations, a high-output mode selector button may be available on a handle or hub. FIG. 61 shows different views of the high voltage generator.

[0290] The design variants of the high voltage generator pertain to the way in which the high voltage multiplier is driven. The variants have an impact on the safety and complexity (cost) of design. The differences between variants come down to the way in which the high voltage multiplier is connected to the high voltage dual half-bridge driver.

[0291] The high voltage multiplier must be powered with the AC signal. The general rule is that the N-stage multiplier delivers at the output high voltage of the value (’A * N * Vpp), where Vpp is a peak-to-peak voltage of the input signal driving the multiplier.

[0292] The high voltage dual half-bridge driver can deliver either a signal being a square wave of max. amplitude 400V coming from one of the half bridge outputs and ground, or a square wave of square wave of max. amplitude 800V coming from the two half bridge outputs. It is important to note that in the latter case neither of the two signal lines is ground,and the potential between ground and any signal line changes periodically between OV and 400V.

[0293] In the design the electronics components should be enclosed and not accessible to the user, but the potentiometer and on / off switch pose danger of breaking the isolation barrier.

[0294] FIG. 62 shows a block diagram of an example high voltage generator 6200. FIG. 63 shows a block diagram of another example high voltage generator 6300. In this example, the high voltage divider is driven with the signal between the outputs of the high voltage dual half-bridge driver. Since the peak-to-peak voltage between the outputs is 400V (max value), the 10-stage high voltage multipliers connected in series must be used to generate 4KV voltage at the output.

[0295] FIG. 64 shows a block diagram of another example high voltage generator 6400. In this example, the high voltage multiplier is driven with the signal between the outputs of the high voltage dual half-bridge driver. Since the peak-to-peak voltage between the outputs is 800V (max value), a 10-stage high voltage multiplier allows for generation of the 4KV at the output. Note, in this configuration, neither of the output high voltage lines is on a ground level. The potential between ground and any signal line changes periodically between 0V and 400V.

[0296] FIG. 65 shows a block diagram of another example high voltage generator 6500. In this example, the output of the high voltage multiplier is separated from the input of the high voltages multiplier with a transformer having a 1 : 1 winding ratio. The primary winding of the transformer is driven with the signal between the outputs of the high voltage dual halfbridge driver. Since the peak-to-peak voltage between the outputs is 800V (max value), a 10- stage high voltage multiplier allows for generation of 4KV at the output. FIG. 66 shows a table 6600 comparing different power supply designs.Catheter ring / channel / data scheme for storing UI layout

[0297] The IVL catheter is built of modules consisting of one or more emitters (spark gaps). Because of their shapes, they are called rings. If there is more than one emitter in the ring, they are connected in series. The catheter may have up to five rings.

[0298] One or more rings form channels. If the channel consists of multiple rings, they are connected in series. There may be up to four channels in the catheter.

[0299] If a channel is energized, all rings in this channel generate spark at the same time. Different physical patterns of rings in the catheter allow to create different spark patterns for better efficiency of the IVL procedure.

[0300] The data describing catheter is stored in the non-volatile memory (1-wire eeprom) located in the catheter. The information stored in the eeprom can be divided into three groups: General information (such as catheter type, serial number and lot number), parameters pertaining to the IVL procedure (such as pulse voltage and duration, output scaler, number of allowed uses, etc.), and parameters describing catheter configuration, i.e., number of rings, number of channels, and their layout.

[0301] The latter group can be implemented as two data structures: a variable defining number of channels in the catheter and an array defining the layout of the rings within each channel. The array consists of several bytes each corresponding to rings in the catheter. The bits in each byte signify the ring layout in a particular channel.

[0302] FIG. 67 shows an example implementation of rings and an associated array. Notably, the rows of the array can correspond to channels and columns can correspond to rings. From this array the generator code can build the configuration of the UI screen. In this case, the layout may consist of four objects.

[0303] FIG. 68 A shows a possible user interface based on the array of FIG. 67. The ovals 1.4 represent rings on the catheter shaft. They correspond to touch areas on the screen (soft buttons). By touching those areas which the user can select / deselect the channels that are active are a part of the firing sequence (they act as toggle buttons). In this case, touching either oval 1 or oval 4 will cause both of them to change their state. Ovals 2 and 3 will act as independent buttons.

[0304] FIG. 68B shows the user interface after the user has turned on rings 1, 3, and 4 (by touching either oval 1 or oval 4, and touching oval 3. After initiating the sequence, the order of firing of the rings may be: rings 1 and 4 will fire simultaneously (since both of them are on the same channel 1). ring 3 will fire (since it is the only ring on channel 3).

[0305] After selecting the active rings, the user will be able to tell which ones will fire but will not be able to tell the exact sequence of firing. Also, when making a selection, the user will have no idea which rings are individual, and which are shared with the channel. One of the solutions would be to assign different colors to the eggs-rings such that all rings on the same channel are the same color. The user would immediately see which rings will fire in groups. Another solution would be to draw lines symbolizing connections between rings / eggs, but the layout has to be created on the fly, thus, less ideal.Power supply high voltage output short protection.

[0306] During normal operation the load to the high voltage multiplier is very small. Even during a discharge, after the sparkler is connected to the output capacitor and the arc is pulled, the arcing period lasts a few microseconds after which either the voltage drops down,and then the arc is broken, or the capacitor is disconnected from the sparkler. The energy flow caused by this event is too short to cause any damage.

[0307] The principle of multiplying the voltage in the Villard cascade multiplier is to change N111capacitor in the ladder with the voltage being a sum of voltages of capacitors from 1 to N-1.

[0308] The disadvantage of this solution is that the charge transferred to the next capacitor is smaller (since the current charging it is equal to Yi of the current charging previous capacitor) which increases output impedance of each stage.

[0309] After a short period of time all capacitors are fully charged and the current stops flowing.

[0310] In the case of a short, most of the power is dissipated in the input cap which in the design has capacitance IpF. Since the frequency of the driver was set to 1kHz, the power dissipated in the cap for 200VRMS input voltage will be 250W. The ceramic cap forced to dissipate such power will explode within milliseconds.

[0311] FIGS. 69 A and 69B show current flow for each of the halves of the drive signal for the worst-case scenario (device started with a short at the output, all capacitors discharged). Because of the short the capacitor luF / 630V is periodically charged in both directions, which corresponds to the current flowing through it. During operation without the load, the capacitors get charged and the current flowing through this capacitor during positive half of the driving signal is very small — it only covers leakage currents of the capacitors in the multiplier.

[0312] A proposed short protection may include a resistor between the last stage of the output of the high voltage divider and the output capacitor.

[0313] FIG. 69C shows a schematic of a high voltage divider and a short protection resistor. In some examples, a resistor of 20kQ output the capacitor 20.4 nF the time constant RC will be 408 ps, so its impact on charging the output capacitor will be adding about 2 ms to the charging time (i.e., the repetition time will get longer by 2ms), which is negligible.

[0314] In case of a short, most of the power will be dissipated in the resistor. In the worst-case scenario (VRMS = 200V) this power will be equal to 2W. A 5W resistor will easily dissipate this power without getting too hot.Short protection and bleeders

[0315] The short protection consists of the resistor 30kQ / 2W (50% higher than projected before) connected between the last stage of the high voltage multiplier and the bank of output capacitors. In case of an electrical short, the resistor limits the output current to 6.6mARMs (13.3mApEAK). The power dissipated in the resistor during the short is 1.3W.

[0316] Despite the higher resistor value, the impact of the resistor on the repetition time is negligible (T = RC = 30kQ * 4 * 6.8nF = 816ms, TDELAY = 4ms). FIG. 69D shows the start time of the device (4kV output voltage, all capacitors discharged, worst case scenario).Repetition time remains at the 250 ms level.

[0317] The bleeder resistors discharge the output voltage if the device is not powered.The total value of the bleeder resistors is 100MQ. With this value the bank of output capacitors is discharged from 4kV (worst case scenario) to safe 24V within 50 seconds (under “no other load” at the output conditions).

[0318] The bleeder resistors are also used for indicating the voltage at the output (with a DVM connected to the terminals). A voltmeter of 10MQ input resistance should be used to achieve required accuracy of measurement.

[0319] FIG. 70 shows a schematic of an example output stage with bleeder resistors. The short circuit protection is marked, e.g., in green, and the bleeder resistors are marked in blue.

[0320] FIG. 71 A shows a breadboard implementation of a high voltage generator. The high voltage generator may include:• A) Power entry module DC21 equipped with the on / off switch.• B) Medical grade switching power supply MINT 1275 A2414K01. The module delivers voltages 24V and 5V (only 24V is used in the breadboard.) The module is equipped with input (mains) fuses, so no additional fuses are used. The module provides 4kV galvanic separation from mains.• C) Adjustable switching voltage regulator YH11068 A. The module is powered with 24V coming from the switching power supply B. The voltage at the output of the module can be adjusted within 45V-405V range with 10-tum potentiometer [1],• D) Logic board. The board was assembled on the protype board. It consists of three submodules: o 12V voltage regulator supplying voltage to the driver D. The regulator is powered from the 24V generated by B. o 5 V voltage regulator supplying voltage to the on-board microcontroller PIC24FV32KA302. The regulator is powered from the 24V generated by B. o The microcontroller PIC24FV32KA302 generating dive signals for the driver D. The microcontroller is connected to the switch [2] which turns drive signal generation on and off thus turning on or off the high voltage. The drive signal generation is signaled by the blinking LED on the board. The code alsoimplements rudimentary safety functions: if the breadboard is turned on when the switch [2] is in on position, the drive signal is not generated, but the LED blinks fast. Only after switch [2] is switched to the off position does the LED stop blinking, and then switching it back on turns drive signal generation on.• E) High voltage dual half-bridge driver EVALPWD13F60. (For simplicity an evaluation board of PWD13F60 driver was used.) The driver chip is powered with 12V generated by the regulator [a] on the logic board D, and it is driven by the signals generated by the microcontroller [c] on the logic board D. The power MOSFETS of the driver chip are powered with the adjustable high voltage coming from Adjustable switching voltage regulator C.• F) Voltage multiplier. A classic Villard cascade voltage multiplier is driven with the high voltage output signal coming from the driver E. The module was divided into three parts: two high voltage ladders lOx [I] and [II], and the output capacitor bank [III],

[0321] FIG. 71B shows an enclosure surrounding the power supply of FIG. 71 A.

[0322] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the benefits described herein.

[0323] The process parameters and sequence of steps described and / or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and / or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed. The various example methods described and / or illustrated herein may also omit one or more of the steps described or illustrated herein or include additional steps in addition to those disclosed.

[0324] When a feature or element is herein referred to as being "on" another feature or element, it can be directly on the other feature or element or intervening features and / or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being "connected", "attached" or "coupled" to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected", "directly attached" or "directly coupled" to another feature or element, there are no intervening featuresor elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.

[0325] Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ".

[0326] Spatially relative terms, such as "under", "below", "lower", "over", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly", "downwardly", "vertical", "horizontal" and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

[0327] Although the terms “first” and “second” may be used herein to describe various features / elements (including steps), these features / elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature / element from another feature / element. Thus, a first feature / element discussed below could be termed a second feature / element, and similarly, a second feature / element discussed below could be termed a first feature / element without departing from the teachings of the present invention.

[0328] Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising” means various components can be co-jointly employed in the methods andarticles (e.g., compositions and apparatuses including device and methods). For example, the term “comprising” will be understood to imply the inclusion of any stated elements or steps but not the exclusion of any other elements or steps.

[0329] In general, any of the apparatuses and methods described herein should be understood to be inclusive, but all or a sub-set of the components and / or steps may alternatively be exclusive, and may be expressed as “consisting of’ or alternatively “consisting essentially of’ the various components, steps, sub-components or sub-steps.

[0330] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word "about" or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and / or position to indicate that the value and / or position described is within a reasonable expected range of values and / or positions. For example, a numeric value may have a value that is + / - 0.1% of the stated value (or range of values), + / - 1% of the stated value (or range of values), + / - 2% of the stated value (or range of values), + / - 5% of the stated value (or range of values), + / - 10% of the stated value (or range of values), etc. Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value " 10" is disclosed, then "about 10" is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also understood that when a value is disclosed that "less than or equal to" the value, "greater than or equal to the value" and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value "X" is disclosed the "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a numerical value) is also disclosed. It is also understood that the throughout the application, data is provided in a number of different formats, and that this data represents endpoints and starting points, and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0331] Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. For example, the order in which various described method steps are performed may often be changed in alternative embodiments, and in otheralternative embodiments one or more method steps may be skipped altogether. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.

[0332] The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

Claims

CLAIMSWhat is claimed is:

1. An apparatus comprising: an elongate catheter body; an inflatable balloon at a distal end region of the elongate catheter body; a plurality of acoustic emitters attached to the elongate catheter body within the inflatable balloon, wherein acoustic emitter comprises: an electrically insulating ring mount, a first emitter pair comprising a first pair of electrodes, a second emitter pair comprising a second pair of electrodes, and a first spark aperture formed through a surface of the ring mount that is radially outward of and between the first pair of electrodes; a second spark aperture formed through the surface of the ring mount that is radially outward of and between the second pair of electrodes, wherein each spark aperture forms a spark gap region; a control circuit configured to control the application of electrical energy to each of the acoustic emitters; an independently addressable electrical line extending proximally to the control circuit from a first electrode of the first pair of electrodes of each of the acoustic emitters; wherein a second electrode of the first pair of electrodes is electrically coupled to a first electrode of the second pair of electrodes of each of the acoustic emitters; and wherein a second electrode of the second pair of electrodes of each of the acoustic emitters is electrically coupled to a common electrical return line extending proximally to the control circuit.

2. The apparatus of claim 1, wherein the control circuit is integrated into the catheter body.

3. The apparatus of claim 1, wherein the control circuit is configured to independently control the application of energy to each acoustic emitter.

4. The apparatus of claim 1, wherein the plurality of acoustic emitters comprises three or more acoustic emitters.

5. The apparatus of claim 1, wherein each spark aperture forms a spark gap region having a concave surface that is configured to focus released acoustic energy.

6. The apparatus of claim 5, wherein the concave surface of each of the spark apertures comprises an acoustically reflective material.

7. The apparatus of claim 1, wherein each acoustic emitter of the plurality of acoustic emitters is attached to the elongate catheter body at a discrete contact point.

8. The apparatus of claim 1, wherein each emitter pair is held between an outer surface of the ring mount and an outer surface of the elongate catheter body.

9. The apparatus of claim 1, wherein a radially outer surface of each emitter pair is covered by the ring mount.

10. The apparatus of claim 1, wherein at least one of the plurality of acoustic emitters is axially movable relative to the balloon.

11. The apparatus of claim 1, wherein at least one of the plurality of acoustic emitters is radially movable relative to the balloon.

12. The apparatus of claim 1, wherein the first and second spark apertures of each acoustic emitter is oriented in a radially offset position relative to an adjacent acoustic emitter.

13. The apparatus of claim 1, further comprising an arc generator configured to generate a high voltage pulse sufficient to create a plasma arc between the emitters or the emitter pair resulting in a mechanical shock wave within the balloon.

14. The apparatus of claim 1, wherein the ring mount comprises a plurality of ribs extending longitudinally from an outer region of the ring mount to the elongate catheter body, wherein the first spark aperture is formed, in part, by a gap in a rib between the first pair of electrodes.

15. The apparatus of claim 14, wherein the electrodes of the first emitter pair are separated by one or more ribs of the plurality of ribs.

16. An apparatus comprising: an elongate catheter body; an inflatable balloon at a distal end region of the elongate catheter body; a plurality of acoustic emitters attached to the elongate catheter body within the inflatable balloon, wherein acoustic emitter comprises: an electrically insulating ring mount; a first emitter pair comprising a first pair of electrodes; a second emitter pair comprising a second pair of electrodes; and a first spark aperture formed through a surface of the ring mount that is radially outward of and between the first pair of electrodes;a second spark aperture formed through the surface of the ring mount that is radially outward of and between the second pair of electrodes; wherein each spark aperture forms a spark gap region having a concave surface that is configured to focus released acoustic energy.

17. The apparatus of claim 16, wherein the plurality of acoustic emitters are attached to the elongate catheter body at a plurality of discrete contact points.

18. The apparatus of claim 16, wherein each emitter pair is held between an outer surface of the ring mount and an outer surface of the elongate catheter body.

19. The apparatus of claim 16, wherein a radially outer surface of each emitter pair is covered by the ring mount.

20. The apparatus of claim 16, wherein the concave surface of each of the spark apertures comprises an acoustically reflective material.

21. The apparatus of claim 16, wherein at least one of the plurality of acoustic emitters is axially movable relative to the balloon.

22. The apparatus of claim 16, wherein at least one of the plurality of acoustic emitters is radially movable relative to the balloon.

23. The apparatus of claim 16, wherein the first and second spark apertures of each acoustic emitter is oriented in a radially offset position relative to an adjacent acoustic emitter.

24. The apparatus of claim 16, further comprising an arc generator configured to generate a high voltage pulse sufficient to create a plasma arc between the emitters or the emitter pair resulting in a mechanical shock wave within the balloon.

25. The apparatus of claim 16, wherein the ring mount comprises a plurality of ribs extending longitudinally from an outer region of the ring mount to the elongate catheter body, wherein the first spark aperture is formed, in part, by a gap in a rib between the first pair of electrodes.

26. The apparatus of claim 25, wherein the electrodes of the first emitter pair are separated by one or more ribs of the plurality of ribs.

27. The apparatus of claim 16, wherein the first emitter pair and the second emitter pair share an electrode.

28. The apparatus of claim 16, further comprising a control circuit that is configured to control the application of electrical energy to each of the acoustic emitters.

29. The apparatus of claim 28, wherein the control circuit is integrated into the catheter body.

30. The apparatus of claim 16, wherein the emitter pair on each ring mount of the plurality of acoustic emitters are independently addressable by a controller configured to control the application of energy to each emitter pair.

31. An apparatus comprising: an elongate catheter body; an inflatable balloon at a distal end region of the elongate catheter body; a plurality of acoustic emitters attached to the elongate catheter body at a plurality of discrete contact points and within the inflatable balloon, wherein each acoustic emitter comprises: an electrically insulating ring mount; an emitter pair, wherein each emitter of the emitter pair is held between an outer surface of the ring mount and an outer surface of the elongate catheter body; and a spark aperture formed through a radially outward surface of the ring mount between the emitters of the emitter pair that is configured to focus released acoustic energy.

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