Intravascular lithotripsy catheter

Abstract

An intravascular lithotripsy (IVL) catheter for treating vessel occlusions comprises a catheter shaft with a longitudinal axis, a balloon capable of inflation and deflation with fluid, and one or more emitters within the balloon's interior. These emitters can emit acoustic waves when the balloon is inflated. The catheter also includes an inner member partially internal to the balloon and wires embedded in the inner member, which are coupled to the emitters and configured to transmit signals to them.

Description

INTRAVASCULAR LITHOTRIPSY CATHETERBACKGROUNDFIELD

[0001] The present disclosure relates to lithotripsy systems for treating calcifications. More specifically, the present disclosure relates to intravascular lithotripsy catheters useful for disturbing calcified lesions of body vessels.BACKGROUND INFORMATION

[0002] Cardiovascular diseases are a leading cause of morbidity and mortality worldwide. A significant number of these conditions involve the formation of calcified lesions within the blood vessels, which can lead to restricted blood flow and increased risk of heart attacks and strokes. Calcified lesions are particularly challenging to treat due to their hard and brittle nature.

[0003] Traditional methods for addressing calcified lesions include balloon angioplasty, which involves inflation of a balloon within the vessel to compress the plaque. Also, atherectomy, which involves mechanically removing the plaque, is used to treat calcified lesions. Both of these methods, however, have limitations. For example, balloon angioplasty may not adequately open heavily calcified plaques and can lead to vessel dissection or perforation. Furthermore, atherectomy, while effective in removing plaque, carries risks such as embolization and damage to the vessel wall.

[0004] An emerging technique for treating calcified lesions is intravascular lithotripsy (IVL). IVL uses acoustic pressure waves to fracture a calcified plaque. For example, IVL can use shock waves or ultrasonic energy to break up kidney stones in a urinary system. In the context of vascular interventions, IVL may be used to fracture calcified plaque in a blood vessel to make the plaque more pliable and easier to open with subsequent balloon angioplasty. An IVL catheter can include lithotripsy emitters to generate wave energy at a vessel location, and a balloon that can be expanded into the disrupted lesion to prepare the vessel location for stenting. Accordingly, the method has the potential to improve the safety and efficacy of percutaneous coronary interventions (PCI) in patients with heavily calcified lesions.

[0005] A chronic total occlusion (CTO) is a complete or near-complete blockage in one or more coronary arteries. CTOs typically persist for three months or longer. CTOs are particularly difficult to safely address with interventional methods, as a medical device such as one having a balloon must first pass into the blockage. Often multiple expensive1 Docket No.: 23812.31.2Amedical devices are required to treat a CTO or near CTO, such as specialized guidewires, cutting balloons, atherectomy devices, IVL catheters or other devices for vessel preparation.

[0006] IVL catheter systems may have crossing profiles that make traversing lesions difficult. In particular, electrodes and wiring are typically disposed externally to certain members and between the balloon and the certain internal members.SUMMARY

[0007] An intravascular lithotripsy (IVL) catheter for treating vessel occlusions comprises a catheter shaft with a longitudinal axis, a balloon capable of inflation and deflation with fluid, and one or more emitters within the balloon's interior. These emitters can emit acoustic waves when the balloon is inflated. The catheter also includes an inner member partially internal to the balloon and wires embedded in the inner member, which are coupled to the emitters and configured to transmit signals to them.

[0008] An intravascular lithotripsy (IVL) catheter is described. In an embodiment, the IVL catheter includes a catheter shaft having a longitudinal axis. The IVL catheter includes a balloon having an interior and an exterior. The balloon is capable of being inflated and deflated with a fluid. The IVL catheter includes one or more emitters within the interior of the balloon. The one or more emitters are capable of emitting an acoustic wave within the balloon when the balloon is inflated. The IVL catheter includes an axial- firing emitter located distal to the interior to emit acoustic waves in an axial direction along the longitudinal axis.

[0009] An IVL system is described. In an embodiment, the IVL system includes an IVL control system including a pulse generator. The IVL system includes an IVL catheter including a control handle coupled to the pulse generator, a catheter having a longitudinal axis, a balloon having an interior and an exterior, the balloon being inflatable by a fluid, and one or more emitters within the interior of the balloon capable of emitting an acoustic wave within the balloon when the balloon is inflated. The IVL catheter includes an axial- firing emitter located distal to the interior. The axial-firing emitter is to emit, based on a signal received from the pulse generator through the control handle, acoustic waves with a substantial component traveling in a distal, axial direction along the longitudinal axis.

[0010] A method is described. In an embodiment, the method includes delivering an IVL catheter over a guidewire to a calcified lesion in a body lumen. The IVL catheter includes a catheter shaft having a longitudinal axis, an inflatable balloon mounted on the catheter shaft and having an interior and an exterior, and an axial-firing emitter located2 Docket No.: 23812.31.2Adistal to the interior. The method includes activating the axial-firing emitter to emit acoustic waves having a substantial component traveling in a distal, axial direction along the longitudinal axis into the calcified lesion while the balloon is deflated. The method includes advancing the IVL catheter through the calcified lesion while the balloon is deflated.

[0011] The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings.

[0013] FIG. 1 is a diagrammatic cross section of a vessel illustrating an example activation of an intravascular lithotripsy (IVL) catheter adjacent to a calcified lesion, in accordance with an embodiment.

[0014] FIG. 2 is a perspective view of an IVL system, in accordance with an embodiment.

[0015] FIG. 3 is a side view of an over-the-wire IVL catheter, in accordance with an embodiment.

[0016] FIG. 4 is a side view of a rapid exchange IVL catheter, in accordance with an embodiment.

[0017] FIG. 5 is a side view of a control handle of an IVL catheter, in accordance with an embodiment.

[0018] FIG. 6A is a cutaway perspective view of a distal portion of an IVL catheter, in accordance with an embodiment.

[0019] FIG. 6B is a cutaway perspective view of a distal portion of an IVL catheter, in accordance with an embodiment having wires embedded in an inner member.

[0020] FIG 6C is a cutaway perspective view of a distal portion of an IVL catheter, in accordance with an embodiment having wires embedded in an inner member with exposed3 Docket No.: 23812.31.2Apoints forming electrodes.

[0021] FIG 6D is a cutaway perspective view of a distal portion of an IVL catheter, in accordance with an embodiment having wires embedded in an inner member in a spiraled fashion.

[0022] FIG 6E is a cutaway perspective view of a distal portion of an IVL catheter, in accordance with an embodiment having wires embedded in an inner member including axially overlapping wires.

[0023] FIG. 7A is a sectional view, taken about line A-A of FIG. 6A, of a catheter shaft of an IVL catheter, in accordance with an embodiment.

[0024] FIG. 7B is a sectional view, taken about line A-A of FIG. 6B, of a catheter shaft of an IVL catheter, in accordance with an embodiment having wires embedded in an inner member.

[0025] FIG. 7C is a sectional view, taken about line A-A of FIG. 6C, of a catheter shaft of an IVL catheter, in accordance with an embodiment having wires embedded in an inner member.

[0026] FIG. 8A is a side view of a distal portion of an IVL catheter, in accordance with an embodiment.

[0027] FIG. 8B is a side view of a distal portion of an IVL catheter, in accordance with an embodiment having wires embedded in an inner member.

[0028] FIG. 9A is a sectional view of a distal tip portion of an IVL catheter, in accordance with an embodiment.

[0029] FIG. 9B is a perspective view of a distal tip portion of an IVL catheter, in accordance with an embodiment.

[0030] FIG. 9C is a front facing view oof a distal tip portion of an IVL catheter, in accordance with an embodiment.

[0031] FIG 9D is a front facing view of a distal tip portion of an IVL catheter, in accordance with an embodiment.

[0032] FIG. 10 is a sectional view of a catheter tip of an IVL catheter, in accordance with an embodiment.

[0033] FIG. 11 is a sectional view of a catheter tip of an IVL catheter, in accordance with an embodiment.

[0034] FIG. 12 is a schematic view of a catheter tip of an IVL catheter having a refractive focusing element, in accordance with an embodiment.

[0035] FIG. 13 is a schematic view of a catheter tip of an IVL catheter having a4 Docket No.: 23812.31.2Areflective focusing element, in accordance with an embodiment.

[0036] FIG. 14 is a cross-sectional view of a pressure pulse directing balloon of an IVL catheter, in accordance with an embodiment.

[0037] FIG. 15 is a cross-sectional view of a pressure pulse directing balloon of an IVL catheter, in accordance with an embodiment.

[0038] FIG. 16 is a cross-sectional view of a pressure pulse directing balloon of an IVL catheter, in accordance with an embodiment.

[0039] FIG. 17 is a cross-sectional view of a pressure pulse directing balloon of an IVL catheter, in accordance with an embodiment.

[0040] FIG. 18 is a cross-sectional view of a pressure pulse directing balloon of an IVL catheter, in accordance with an embodiment.

[0041] FIG. 19 is a flowchart of a method of treating a calcified lesion using an IVL catheter, in accordance with an embodiment.

[0042] FIGS. 20-23 are schematic views of operations of a method of treating a calcified lesion using an IVL catheter, in accordance with an embodiment.

[0043] FIG. 24 is a schematic of a control circuit of an electrode controller, in accordance with an embodiment.

[0044] FIG. 25 is a schematic of a control circuit of an electrode controller, in accordance with an embodiment.

[0045] FIG. 26 is a truth table of the control circuit of FIG. 25, in accordance with an embodiment.

[0046] FIG. 27 is a schematic of a control circuit of an electrode controller, in accordance with an embodiment.

[0047] FIG. 28 is a truth table of the control circuit of FIG. 27, in accordance with an embodiment.

[0048] FIG. 29 is a pictorial view of a graphical user interface of an IVL system, in accordance with an embodiment.

[0049] FIG. 30A is a perspective view of a distal tip portion of an IVL catheter with a flex tip, in accordance with an embodiment.

[0050] FIG. 30B is a perspective view of a distal tip portion of an IVL catheter with a flex tip, in accordance with an embodiment.

[0051] FIG. 30C is a perspective view of a distal tip portion of an IVL catheter with a flex tip, in accordance with an embodiment.

[0052] FIG. 30D is a perspective view of a distal tip portion of an IVL catheter with a5 Docket No.: 23812.31.2Aflex tip, in accordance with an embodiment.

[0053] FIG. 30E is a perspective view of a distal tip portion of an IVL catheter with a flex tip, in accordance with an embodiment.

[0054] FIG. 30F is a perspective view of a distal tip portion of an IVL catheter with a flex tip, in accordance with an embodiment.

[0055] FIG. 31 is a pictorial view of a computing system of an IVL system, in accordance with an embodiment.DETAILED DESCRIPTION

[0056] Embodiments describe an intravascular lithotripsy (IVL) catheter having directional energy delivery. As described below, the intravascular lithotripsy catheter can be used to disturb calcified lesions of a blood vessel, such as a calcified chronic total occlusion in a coronary artery or a peripheral artery. The intravascular lithotripsy catheter may, however, be used in other applications, such as disrupting calcifications in a urinary system. Thus, reference to use of the intravascular lithotripsy catheter in a particular anatomy is not limiting.

[0057] In various embodiments, description is made with reference to the figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions, and processes, in order to provide a thorough understanding of the embodiments. In other instances, well-known processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure the description. Reference throughout this specification to “one embodiment,” “an embodiment,” or the like, means that a particular feature, structure, configuration, or characteristic described is included in at least one embodiment. Thus, the appearance of the phrase “one embodiment,” “an embodiment,” or the like, in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments.

[0058] The use of relative terms throughout the description may denote a relative position or direction. For example, “distal” may indicate a first direction along a longitudinal axis of an intravascular lithotripsy catheter. Similarly, “proximal” may indicate a second direction opposite to the first direction. Such terms are provided to establish relative frames of reference, however, and are not intended to limit the use or6 Docket No.: 23812.31.2Aorientation of an IVL catheter to a specific configuration described in the various embodiments below.

[0059] Existing IVL catheters incorporate lithotripsy emitters within a balloon to direct wave energy radially and uniformly outward toward a surrounding calcified lesion. Some lesions, such as chronic total occlusions, however, may not be initially crossable by the IVL catheter and therefore the radially directed energy cannot penetrate the calcifications of the lesion. Furthermore, existing IVL catheter balloons may not adequately direct the wave energy, either axially into a chronic total occlusion or radially into a surrounding lesion. For example, some existing IVL catheters are only indicated for use in lesions having calcifications surrounding a minimum angle of a vessel wall because generated wave energy is lost through healthy tissue and cannot adequately break up the calcifications. Finally, when existing IVL catheters are wedged into tight lesions to try to bring the emitters within the balloon against the lesion, the emitters can wedge against the balloon and the energy emitted by the emitters can damage the balloon. Accordingly, IVL treatments could benefit from an IVL catheter that can direct wave energy in predetermined directions, such as forward into chronic total occlusions or laterally toward an eccentric calcification, without damaging a balloon.

[0060] In an aspect, an IVL catheter has directional energy delivery. The directionality of the IVL catheter may be based on an IVL emitter design or an IVL balloon design. For example, the IVL catheter can incorporate an axial-firing emitter to emit acoustic waves substantially in an axial direction, e.g., into a chronic total occlusion. The waves can break up the chronic total occlusion to permit passage of the IVL catheter. Furthermore, the axial-firing emitter may be distal to a balloon to avoid damaging the balloon with the emitted energy. The IVL catheter may also incorporate radial-firing emitters and, optionally, a pressure pulse directing balloon to direct acoustic waves emitted by the radial-firing emitters in a particular radial direction. The waves can break up surrounding calcifications to allow the lesion to be remodeled by the balloon. Accordingly, the IVL catheter can combine two modes of IVL operation: axial firing for substantially forward directed energy waves into a calcified lesion without subjecting the balloon to wear from energy traveling from inside the balloon to outside the balloon, and radial firing after crossing the calcified lesion to break up the calcified blockage for subsequent expansion by the balloon.

[0061] Referring to FIG. 1, a diagrammatic cross section of a vessel illustrating an example activation of an intravascular lithotripsy catheter adjacent to a calcified lesion is7 Docket No.: 23812.31.2Ashown in accordance with an embodiment. An IVL catheter 100 can be introduced into a bodily vessel 102, such as a blood vessel, of a patient over a guidewire 103. The IVL catheter 100 includes a balloon 104 mounted on a catheter shaft 106. The balloon 104 is capable of being inflated and deflated with a fluid, as described below. The blood vessel 102, which serves as the target anatomy, contains a lesion 108 within a vessel wall 110. More particularly, the lesion 108 can include a calcified lesion restricting the flow of a medium, such as blood, through the vessel 102.

[0062] As the IVL catheter 100 is advanced through the vessel 102, the balloon 104 is positioned adjacent to the calcified lesion 108. Once in place, the balloon 104 can be expanded against the vessel wall 110. One or more emitters (FIG. 6A) can be contained within the balloon 104 and, optionally, one or more emitters can be located outside of the balloon 104 (FIG. 8 A). The emitters can include elements for generating short pressure pulses. Examples include electrodes providing electrical spark gaps, optical focusing elements or optical targets with optical fibers, or lumens and outlets for pressurized gas. Other mechanisms for generating the short pressure pulses may be used. In an embodiment, the emitters may be activated to generate an electrical arc 112. This electrical arc 112 produces a pressure wave 114 that propagates outward toward the lesion 108.

[0063] When the emitters fire, high-pressure acoustic pulses, e.g., intraluminal short pressure pulses or shock waves, expand and travel spherically outward from the emitters. For example, the pressure waves 114 generated by the electrical arc 112 can travel away from the emitters to cause one or more cracks 116 to form in the calcified lesion 108. More particularly, when the waves encounter calcification in the vessel wall 110, stresses are created and the calcification fractures. These cracks 116 disrupt the lesion 108, making it more pliable and easier to treat with subsequent interventions, such as balloon angioplasty. For example, the fractured calcification can allow the balloon 104 to expand more completely, opening the vessel 102, and allowing for stent placement and stent expansion.

[0064] The illustration of FIG. 1 demonstrates the mechanism by which the IVL catheter 100 effectively targets and disrupts calcified lesions 108 within the blood vessel 102, thereby improving the safety and efficacy of percutaneous coronary interventions (PCI) in patients with heavily calcified lesions. The above description is a general description of an IVL procedure, and it will be appreciated that special clinical situations may have difficult to cross lesions 108. For example, the lesion 108 may create a total or near total blockage of the vessel 102, e.g., a chronic total occlusion, and the guidewire 103 or balloon 104 may not be able to cross the lesion 108 initially to allow for the subsequent8 Docket No.: 23812.31.2Aexpansion and activation of the emitters. In such a case, an IVL catheter 100 as described below can be advantageous. More particularly, an IVL catheter 100 that delivers energy axially, e.g., forward from a distal end, can be useful to break through the calcified blockage and allow guidewire advancement and radial -fire emitter positioning. The radialfiring emitters can be placed without the need to exchange the device, and can deliver unfocused radial shockwaves to break up the lesion 108 more fully. Advantageously, separating the axially fired shockwave from the unfocused radially fired shockwaves, e.g., by generating the axial shockwave outside of the balloon 104, may save wear and tear on the balloon 104.

[0065] Referring to FIG. 2, a perspective view of an intravascular lithotripsy system is shown in accordance with an embodiment. An IVL system 200 includes an IVL catheter 100 designed to disrupt calcified lesions 108 within a blood vessel 102, as described above. The IVL catheter 100 comprises the balloon 104 mounted on the catheter shaft 106, which can be positioned adjacent to and expanded against a calcified lesion 108 to facilitate the treatment of the lesion. As described below with respect to FIGS. 3-4, the IVL catheter 100 may have an over-the-wire (OTW) or rapid exchange (RX) configuration.

[0066] The IVL system 200 also includes a fluid pump 202 that is fluidically coupled to the balloon 104. The fluid pump 202 can be used to inflate and deflate the balloon 104 as needed during the procedure. For example, the fluid pump 202 can convey a saline solution or mixture of saline and contrast fluid to the balloon 104 to expand the balloon against the vessel wall 110. By controlling the fluid pressure within the balloon 104, the fluid pump 202 ensures that the balloon can be precisely positioned and expanded to effectively target the calcified lesion 108. This controlled inflation and deflation facilitate accurate delivery of lithotripsy energy to the lesion 108.

[0067] In an embodiment, an IVL control system 204 includes a fluid supply subsystem (not shown). For example, the fluid supply subsystem can include a fluid network of tubing, storage tanks, bags, etc. to hold an inflation or emitter bathing fluid, and a pump to convey the fluid through the fluid network to the IVL catheter 100. By way of example, the fluid supply subsystem can be fluidically coupled to a fluid connector of the IVL catheter 100 (FIGS. 3 and 4) to pump the inflation or emitter bathing fluid toward a distal portion of the catheter shaft 106 or balloon 104. The inflation or emitter bathing fluid may, for example, include saline to support balloon inflation and / or spark generation.

[0068] The IVL catheter 100 may be electrically connected to the IVL control system 204 via a control handle 206. The IVL control system 204 can include a pulse generator9 Docket No.: 23812.31.2Athat generates the signals required to activate the emitters. For example, the pulse generator can generate an electrical signal to activate electrodes within the balloon 104 or a distal tip of the IVL catheter 100. Alternatively, the pulse generator can deliver a pulse of high-intensity light, e.g., a laser pulse, to activate an optical emitter, or a high-pressure fluid pulse, e.g., a gas pulse, to activate a pneumatic emitter. The signal can be delivered through the control handle 206, which is coupled to the pulse generator and to the emitters. Accordingly, the emitters can emit, based on the signal received from the pulse generator, acoustic waves either axially or radially, as described below, into an adjacent lesion 108.

[0069] The IVL control system 204 can include a memory storing system settings and / or other instructions which, when executed by a processing device of the IVL system 200, cause the IVL system 200 to transmit the signals to the control handle 206. These signals are transmitted through the control handle 206 to the emitters, which then activate the emitters, e.g., by causing electrodes to generate an electrical arc 112. The emitted energy produces the pressure wave 114 that propagates outward toward the calcified lesion 108. Accordingly, the IVL control system 204 can provide the energy to power the lithotripsy procedure.

[0070] The control handle 206 serves as a user interface for the IVL system 200. The control handle 206 can allow the user to manage the operation of the IVL catheter 100, including the activation of the emitters. Optionally, the control handle 206 can control inflation and deflation of the balloon 104 when the fluid supply subsystem is integral to the IVL control system 204 (not shown). The control handle 206 typically features buttons or other input mechanisms that the user can press to generate the electrical arc 112 and produce the pressure wave 114. The control handle interface ensures that the clinician can easily and effectively control the IVL system 200 during the procedure.

[0071] The IVL system 200 can include an electrode controller configured to deliver one or more energy pulses to the emitters. As described below, each emitter can include one or more electrode pairs to generate the electrical arc 112. More particularly, when electrical energy is supplied to an electrode pair with a sufficient voltage, the electrical arc 112 will form and cause the pressure wave 114. The electrode controller, which may be incorporated in a console of the IVL control system 204 or contained within the control handle 206 can deliver one or more energy pulses to a first set of electrode pairs from among the several electrode pairs while preventing energy pulses from being delivered to the one or more other electrode pairs from the among the several electrode pairs. The selectively applied energy pulse(s) may cause an energy wave to deliver energy to an10 Docket No.: 23812.31.2Aocclusion.

[0072] Referring to FIG. 3, a side view of an over-the-wire intravascular lithotripsy catheter is shown in accordance with an embodiment. The IVL catheter 100 can have an OTW guidewire configuration. In the OTW configuration, the guidewire 103 can enter the IVL catheter 100 through a distal catheter tip and exit the catheter through a hub 302. The OTW configuration allows for precise navigation and positioning of the IVL catheter 100 within the vessel 102. The guidewire 103 provides a stable pathway for the catheter, enabling the clinician to accurately target the calcified lesion 108. Once the catheter is in position, the balloon 104 can be expanded, and the emitters can be activated to generate the pressure waves 114 that disrupt the lesion 108.

[0073] The IVL catheter 100 includes the balloon 104 mounted on the catheter shaft 106, as described below. The catheter shaft 106 can provide structural support and serves as a conduit for the guidewire 103, fluid, and electrical connections necessary for the operation of the IVL system 200. For example, the catheter shaft 106 can connect to the hub 302, which conveys fluid and electrical signals between a distal portion of the IVL catheter 100 and external components. The hub 302 can pass signals between the control handle 206 and the emitters to produce the pressure waves 114. For example, the signals can travel along wires in a cable 304 of the control handle 206, which connects to the hub 302. The wires can extend through the hub 302 and into the catheter shaft 106, and extend distally to the emitters.

[0074] In addition to the electrical connection, the hub 302 can also include a fluid connector 306 to pass fluid from the fluid pump 202 to the balloon 104. This fluid connector 306 can convey fluid between the fluid pump 202 and an inflation lumen in the catheter shaft 106, through the hub 302. The inflation fluid can travel along the catheter shaft 106 into the balloon 104 to inflate and deflate the balloon 104 during a procedure.

[0075] Referring to FIG. 4, a side view of a rapid exchange intravascular lithotripsy catheter is shown in accordance with an embodiment. The IVL catheter 100 can have a RX guidewire configuration. As in the OTW guidewire configuration, the RX version of the IVL catheter 100 can include the catheter shaft 106, the balloon 104, and the hub 302. The hub 302 configuration and guidewire routing of the RX configuration may, however, differ from the OTW configuration.

[0076] In an embodiment, the hub 302 is located at a proximal end of the catheter shaft 106. The hub 302 can include the electrical connector, to allow for the transmission of electrical signals from the IVL control system 204 to the emitters, and the fluid connector11 Docket No.: 23812.31.2A306, to enable the passage of the inflation fluid from the fluid pump 202 to the balloon 104. The hub 302 may not, however, have an exit port for the guidewire 103. The exit port may be a rapid exchange (RX) port 402 positioned distal to the hub 302 along the catheter shaft 106.

[0077] The RX port 402 can be positioned between the distal tip and the hub 302 of the IVL catheter 100. The RX port 402 can include a hole in an outer surface of the catheter shaft 106 that allows the guidewire 103 to transition from a location internal to the catheter shaft 106 to a location external to the catheter shaft 106, e.g., supporting the balloon 104. In an embodiment, the guidewire 103 can enter the IVL catheter 100 through the distal catheter tip and exit through the RX port 402. The RX configuration allows for quick and efficient exchange of the guidewire 103, facilitating precise navigation and positioning of the IVL catheter 100 within the vessel 102. The RX port 402 provides a stable pathway for the catheter, enabling the clinician to accurately target the calcified lesion 108.

[0078] Referring to FIG. 5, a side view of a control handle of an intravascular lithotripsy catheter is shown in accordance with an embodiment. The control handle 206 of the IVL catheter 100 includes a cable 304, a grip 502, a connector 504, and a control element 506. The control handle 206 serves as a user interface for the IVL system 200. More particularly, the grip 502 provides a surface for a user to hold and manipulate the control handle 206 during the procedure. The grip 502 can be ergonomically designed to ensure comfort and ease of use for the user.

[0079] The cable 304 can connect the control handle 206 to the hub 302 of the intravascular lithotripsy catheter. The cable 304 transmits signals, e.g., electrical, optical, or pneumatic signals, from the IVL control system 204 to the emitters within and outside of the balloon 104 of the catheter. The connector 504 can be positioned at the proximal end of the control handle 206. The connector 504 can connect to the IVL control system 204. The connector 504 can receive the signals generated by the IVL control system 204, which then transmit through the cable 304 to the hub 302 and subsequently to the emitters.

[0080] The control element 506 can be integrated into the grip 502 of the control handle 206. The control element 506 can include one or more buttons, switches, or other input mechanisms. The user can press the button(s) to activate the emitters. This activation generates the intraluminal short pressure pulses needed for the lithotripsy procedure. The control element 506 allows the clinician to precisely control the timing and intensity of the pulses, ensuring effective treatment of the calcified lesions 108. The control handle 206, with the integrated grip 502, cable 304, connector 504, and control12 Docket No.: 23812.31.2Aelement 506, provides the interface for the clinician to manage the operation of the intravascular lithotripsy catheter. This design ensures that the clinician can easily and effectively control the lithotripsy procedure, enhancing the safety and efficacy of the treatment.

[0081] Referring to FIG. 6A, a cutaway perspective view of a distal portion of an intravascular lithotripsy catheter is shown in accordance with an embodiment. A catheter tip 602 can be positioned at a distal end of the IVL catheter 100. As described above, the catheter tip 602 facilitates the navigation of the catheter over the guidewire 103 through the blood vessel 102 to the target lesion 108. The catheter tip 602 can be designed to be atraumatic to minimize damage to the vessel walls 110 during the procedure, ensuring safe and effective advancement of the catheter to the site of the calcified lesion 108. More particularly, the catheter tip 602 can receive and track over the guidewire 103 to the target anatomy within the vessel 102. The catheter tip 602 may, as described below, house an axial-firing emitter to deliver energy axially from the distal end of the IVL catheter 100.

[0082] The balloon 104 can be mounted on the catheter shaft 106 and may be positioned adjacent to the catheter tip 602. More particularly, a distal end (e.g., a distal neck) of the balloon 104 can be coupled, e.g., sealed, to the catheter tip 602 and a proximal end (e.g., a proximal neck) of the balloon 104 can be coupled, e.g., sealed, to the catheter shaft 106. The balloon 104 may therefore provide a hermetically sealed interior longitudinally between the catheter tip 602 and the catheter shaft 106. The balloon 104 and a fluid used to inflate the balloon therein can serve as a medium for the transmission of pressure waves 114 generated by emitter pairs 604 within the interior of the balloon 104. More particularly, the emitter pairs 604 can cause the pressure wave 114 used to disrupt the calcified lesion 108. In the example illustrated, each emitter pair 604 includes two emitters, each emitter comprising a cathode and an anode.

[0083] The emitters in a given emitter pair 604 have an orientation that is approximately 180 degrees relative to each other. In the example illustrated, the two emitter pairs 604 are rotated approximately 90 degrees relative to each other. This results in an emitter being disposed at four angles: 0 degrees, 90 degrees, 180 degrees, and 270 degrees. Note that this example simply illustrates one embodiment, and other emitter configurations may be used alternatively or additionally. For example, while emitter pairs are illustrated herein, in other embodiments, a single emitter may be implemented, or multiple emitters could be collocated.

[0084] The IVL catheter 100 can include an inner member 606, which can be integral13 Docket No.: 23812.31.2Ato the catheter shaft 106. More particularly, the catheter shaft 106 can include the inner member 606 located within an outer member 608. The outer member 608 can support the proximal end of the balloon 104. The inner member 606 can extend through the balloon 104 to the distal tip of the catheter. The inner member 606 supports the emitter pairs 604 and may also provide a pathway for the guidewire 103. The inner member 606 can ensure the proper alignment and positioning of the emitter pairs 604 within the balloon 104, which facilitates the effective generation and transmission of pressure waves 114 to the calcified lesion 108.

[0085] Each emitter in the emitter pairs 604 can be an electrode pair contained within the balloon 104 and may be responsible for generating an electrical arc 112 that produces the pressure wave 114. For example, the electrode can include several electrode portions separated by a gap across which the spark is generated. When voltage pulses from the IVL control system 204 are transmitted to the electrode, the electrical spark forms across the gap between the electrode portions. For example, the balloon 104 can be filled with the emitter bathing fluid, which may include a known fluid such as saline, water, or air. For example, the bathing fluid can include saline or another electrolytic solution that supports formation of the electrical spark. The spark creates an electrical arc 112, which in turn produces the pressure wave 114 that propagates outward through the inflation fluid and the balloon wall toward the calcified lesion 108.

[0086] Referring to FIG. 7A, a sectional view of a catheter shaft of an intravascular lithotripsy catheter is shown in accordance with an embodiment. The catheter shaft 106 serves as the main structural component of the intravascular lithotripsy catheter. The catheter shaft 106 provides support and houses various internal components of the IVL catheter 100. For example, the catheter shaft 106 includes the outer member 608 and the inner member 606.

[0087] The outer member 608 can be the outermost layer of the catheter shaft 106. The outer member 608 provides structural support and protection for the internal components of the catheter. The outer member 608 is designed to be biocompatible and bendable, allowing the catheter to navigate through the vascular system without causing damage to the vessel walls 110. The outer member 608 can include a tubular wall extending along a longitudinal axis from the hub 302 to the balloon 104.

[0088] The inner member 606 can be located within the outer member 608 and can provide additional structural support. The inner member 606 may include a tubular wall extending along the longitudinal axis, e.g., coaxial with the outer member 608. The inner14 Docket No.: 23812.31.2Amember 606 can house a guidewire lumen, through which the guidewire 103 may pass. Accordingly, the inner member 606 may extend from the hub 302 to the catheter tip 602, in the OTW version of the IVL catheter 100, or from the RX port 402 to the catheter tip 602, in the RX version of the IVL catheter 100. It will be appreciated that, in the RX version, a hypotube (not shown in cross-section, but proximal to the RX port 402 in FIG. 4) can connect the hub 302 to the distal portion of the IVL catheter 100. More particularly, the hypotube can be a tubular member having a lumen to provide a fluid channel and convey inflation fluid from the fluid connector 306 into an inflation lumen 704 that extends into the balloon 104.

[0089] The inflation lumen 704 can be an internal channel within the catheter shaft 106 between the inner member 606 and the outer member 608. The inflation lumen 704 can allow fluid to be delivered to the balloon 104. The inflation lumen 704 may be an annular space, as shown, or may be a circular space, e.g., within the hypotube of the RX version of the IVL catheter 100. In any case, the inflation lumen 704 permits the passage of the inflation fluid, e.g., a saline solution or mixture, into the balloon 104 to support balloon inflation and spark generation.

[0090] In an embodiment, one or more wires 706 are positioned within the catheter shaft 106 and used to transmit electrical signals from the control handle 206 to the electrodes within the balloon 104. For example, each electrode can be connected to one or more wires 706 to electrify the electrode portions and generate the electrical arc 112. Each wire 706 may be insulated to prevent electrical interference with other components of the IVL catheter 100. The electrical wires 706 can be independently energized by the IVL control system 204 to selectively activate and fire one or more of the emitters 604. For example, as described below, the IVL catheter 100 can include an axial-firing emitter outside of the balloon 104, which may be fired independent of one or more radial -firing emitters in the balloon 104.

[0091] Insulation of the wire(s) 706 may also be provided by a wire sheath 708 that surrounds the wires 706, providing additional insulation and protection. The wire sheath 708 may, for example, be a tubular member or heat shrink that encases the wires 706 between the wire sheath 708 and the inner member 606. The wires 706 may therefore be separated from inflation fluid within the inflation lumen 704. Accordingly, the wires 706 may remain securely in place within the catheter shaft 106 and prevent any potential damage or electrical leakage during navigation of the IVL catheter 100 through the vessel 102.15 Docket No.: 23812.31.2A

[0092] Referring now to FIG 6B and 7B, an alternative example is illustrated. In this example, wires 706 are formed in the inner member 606. In the example shown, four wires are embedded in the inner member 606. These wires may be coextruded into the inner member when fabricating the inner member 606 or otherwise embedded into the inner member. Two wires can be used to provide electrical energy to a first emitter pair 604-1 while two other wires can be used to provide electrical energy to a second emitter pair 604- 2. In this example, the inner member may be insulating with a dielectric strength sufficient for the voltages used. For example, the wires 706, at points in the inner member 606, may have no additional insulation other than the portions of the inner member 606 between the wires.

[0093] In the illustrated example, the emitter pairs 604-1 and 604-2 are embodied as partial cylindrical electrode members.. The partial cylindrical electrode member electrodes have a diameter that is similar or nearly identical to that of the inner member 606 (e.g., within 2% of the size of the inner member). This allows for a lower crossing profile for the IVL catheter 100. To allow the partial cylindrical electrode member electrodes of the emitter pairs 604-1 and 604-2 to have a similar diameter to the inner member 606, the partial cylindrical electrode member electrodes may be joined to portions of the inner member 606 using butt-joints. Alternatively, swaging techniques may be used. The partial cylindrical electrode member electrodes and portions of the inner member may be joined together using a heat bond, over-molded nylon, or other methods.

[0094] For example, a partial cylindrical electrode member electrode / emitter may be implemented in conjunction with coextruded / embedded wiring in the inner member 606, which can mitigate the effect of the partial cylindrical electrode member electrode on the crossing profile of the IVL catheter 100. For instance, the partial cylindrical electrode member electrode (or alternatively in other embodiments, a bridging electrode) may be connected to proximal and adjacent segments of the inner member 606 in a butt-joint fashion. The partial cylindrical electrode member electrode can include one or more grooves (e.g., groove 610) to allow one or more wires (e.g., a ground wire or wires for a distal emitter pair 604-2) to pass between the proximal and distal segments of the inner member 606 to which the partial cylindrical electrode member electrode is connected to maintain the similar diameter and crossing profile. Other wires (e.g., a hot wire, bridging wires, etc) may be conductively connected to the partial cylindrical electrode member electrode from within the adjacent segments of the inner member. If hot wires are included in the groove 610 and / or if multiple wires are included in the groove 610, the wires may16 Docket No.: 23812.31.2Abe insulated to as to prevent short circuiting.

[0095] In some embodiments, the partial cylindrical electrode member electrode can be constructed from a material that is more flexible than stainless steel, such as tungsten- embedded block copolymer (such as Pebax available from Arkema S.A. of La Defense, France), or other metal-embedded polymers. The partial cylindrical electrode member electrode can include platinum-iridium and / or other radiopaque agents to facilitate both conductivity and radiopacity. The partial cylindrical electrode member electrode (or bridging electrode) can comprise a stent-like construction, with a lattice-like structure to improve flexibility.

[0096] Note that while the examples above have illustrated embodiments where wires are coextruded with the inner member, it should be appreciated that in other embodiment other methods of embedding wires in the inner member can be used. For example, in some embodiments, ribbon wires may be used to achieve a flatter profile of the wire within the inner member. As another alternative to coextrusion, a groove may be formed in an inner member, and the groove may be subsequently filled (e.g., via printing conductor material in the groove) with a conductive material and overlaid with an insulating material. Also, while the wires 706 are shown in close proximity, alternative embodiments may include greater spacing between the wires 706. In one embodiment the wires are spaced symmetrically about the device axis (e.g. 90 degrees apart).

[0097] The wires 706 may be embedded in a linear parallel path along the axis of the inner member 606. Alternatively, the wires 706 may include bends to strategically form an electrode pair or optimal wire management path.

[0098] Referring to FIG. 8A, a side view of a distal portion of an IVL catheter is shown in accordance with an embodiment. The IVL catheter 100 can provide a universal treatment that combines axial- and radial-firing emitters in a same device. More particularly, the axial-firing emitters can be used to cross a tight lesion 108, such as a chronic total occlusion, and the radial-firing emitters can be used to break up the lesion 108 to facilitate subsequent angioplasty. Furthermore, the IVL catheter 100 can optionally enhance or focus energy delivery in a particular radial direction, which can enhance treatment of a lesion 108 on one side of a vessel wall 110 and prevent loss of energy through healthy tissue on another side of the vessel wall.

[0099] In an embodiment, the IVL catheter 100 includes the catheter shaft 106 having a longitudinal axis 802. More particularly, the catheter shaft 106 can extend along the longitudinal axis 802 between a proximal end (not shown) and a distal end 804.17 Docket No.: 23812.31.2A

[0100] The balloon 104 can be mounted on the catheter shaft 106. For example, a proximal neck of the balloon 104 can be mounted on the outer member 608 of the catheter shaft 106, and a distal neck of the balloon 104 can be mounted on the inner member 606 of the catheter shaft 106. The balloon 104 can have an interior 806 contained within a balloon wall. The balloon may also have an exterior outside of the balloon wall. More particularly, the interior 806 can include a space contained between the catheter shaft 106 and the balloon wall between the proximal balloon end and the distal balloon end, and the exterior can include a space external to the balloon wall radially outward of the balloon wall relative to the catheter shaft 106.

[0101] The IVL catheter 100 can include one or more emitters 604. In an embodiment, at least one of the emitters 604 is outside of the balloon 104. For example, the IVL catheter 100 can include an axial-firing emitter 808 located distal to the interior 806. The axial- firing emitter 808 may be placed at various locations outside of the balloon 104, e.g., in the exterior of the balloon. The location may allow for the emitter 808 to be spaced apart from tissue to avoid direct contact and excessive heating of the tissue, however, the emitter could have various positions relative to the catheter tip 602. In an embodiment, the axial- firing emitter 808 is at a distalmost location on the catheter. For example, the emitter 808 may be located in the catheter tip 602 at the distal end 804 of the catheter shaft 106. The emitter 808 can be recessed in the tip, a hollow cap may house the emitter, etc. Various non-limiting placements and structures of the axial-firing emitter 808 are described below. Pressure waves 114 generated by the emitter 808 may therefore be used to help cross a tight lesion 108 against which the catheter tip 602 is placed. The emitter 808 may be located along a taper of the tip, e.g., in the tip or mounted on an outer surface of the tapered tip. As described below, integrating the emitter 808 into the tip can shield the generated spark from the surrounding anatomy while producing waves pulses that can propagate forward to disrupt lesion calcifications and promote lesion crossing.

[0102] The axial-firing emitter 808 can include one or more electrodes, as described below, to generate an electrical spark. Alternatively, the axial-firing emitter 808 can include an optical fiber to deliver an optical beam. For example, the optical fiber can deliver a laser to generate shockwaves. In either case, the emitter 808 can generate acoustic waves in the exterior of the balloon 104. The acoustic waves can carry energy that originates in the exterior and remains in the exterior. For example, the energy can remain substantially outside of the balloon wall without any appreciable energy or acoustic waves traveling into the balloon 104. More particularly, the acoustic waves can travel in18 Docket No.: 23812.31.2Aa substantially distal axis direction without any appreciable acoustic wave traveling from the interior of the balloon to the exterior of the balloon. The acoustic waves can propagate forward from the catheter tip 602. More particularly, the axial-firing emitter 808 can be positioned to emit acoustic waves substantially in an axial direction 812, e.g., along the longitudinal axis 802, without impinging on the balloon wall.

[0103] In an embodiment, the IVL catheter 100 includes one or more emitters 604 in the balloon 104. For example, the IVL catheter 100 can include one or more radial-firing emitters 814 mounted on the inner member 606 of the catheter shaft 106 in the interior 806 of the balloon 104. As described above, the radial-firing emitters 814 can include an electrode 816 to generate an electrical spark. For example, the radial-firing emitters 814 can include electrical spark gaps with wire pairs to generate the electrical spark. Alternatively, like the forward-firing electrode, the radial-firing electrodes may include optical focusing elements or optical targets with optical fibers. Accordingly, the radialfiring emitters 814 can be activated to emit acoustic waves substantially in a radial direction 821, e.g., perpendicular to the axial direction 812 of the axially fired acoustic waves, when the balloon is inflated.

[0104] As described above, each emitter, e.g., the axial-firing emitter 808 or the radialfiring emitter 814, can include electrode pairs to generate an electrical spark that induces a pressure wave. For example, the axial-firing emitter 808 can include a first electrode pair 820, and the one or more radial-firing emitters 814 can include a second electrode pair 822 and / or a third electrode pair 824 (which may include the electrode 816). Embodiments of electrode pairs are disclosed in U.S. Patent Application No. 63 / 735,842, filed December 18, 2024, and entitled “Intravascular Lithotripsy Catheter Having Directional Energy Delivery,” and PCT Publication No. WO 2024 / 081361 Al, internationally filed October 12, 2023, and entitled “Intravascular Lithotripsy Devices And Systems With Forward Facing Electrodes And Flex Circuit Arrangements,” which applications are incorporated herein by reference in their entireties.

[0105] The electrode pairs, e.g., electrode pairs 820, 822, and / or 824, can be controlled by an electrode controller, as described below, to supply electrical (or other) energy pulses. The electrode controller is typically implemented apart from an enclosure of the IVL control system 204, such as in the control handle 206 or a console of the IVL control system 204 accessible by the health care provider. As described below, the electrode controller can independently control each of the electrode pairs in the IVL system 200. For example, the first electrode pair 820 could be actuated without actuating electrode19 Docket No.: 23812.31.2Apairs 822, 824. Actuating an electrode pair comprises delivering an energy pulse to the electrode pair causing an electrical arc and concomitant emission of a pressure wave. Accordingly, actuation of the first electrode pair 820 can emit a pressure wave in the axial direction without emitting pressure waves from the second and third electrode pairs 822, 824 in the radial direction. Details of various examples of how independent control of different electrode pairs can be controlled will be illustrated below, e.g., with respect to FIGS. 24-28.

[0106] As described above, the emitters 604 of the IVL catheter 100 can generate sparks or manipulate optical beams. The delivered energy can produce shockwaves that propagate outward, e.g., forward or laterally, toward a target lesion. It will be appreciated that such pressure pulses may be generated by alternative mechanisms. For example, pressurized gas may be delivered in bursts internal or external to the balloon 104 to generate short pressure pulses. The pressure pulses may also be focused, e.g., through refractive or reflective elements such as those described below, or unfocused. In an embodiment, the acoustic waves emitted in the axial direction 812 are focused to target a narrow profile in the forward direction, and the acoustic waves emitted in the radial direction 821 are unfocused to target a broader circumferential arc or profile in the lateral direction.

[0107] Referring to FIG. 8B, an alternative example is illustrated. In this example, similar to the example illustrated in FIG. 7B, wires 706 may be molded or otherwise embedded into the inner member 606. In this example, wires may be routed to the axial firing emitter 808 through the inner member 606, a groove in a partial cylindrical electrode member electrode of the electrode pairs 824, through additional portions of the inner member 606, through a groove in a partial cylindrical electrode member electrode of the electrode pairs 822, through additional portions of the inner member 606 and finally to the axial firing emitter 808. Note that wires in the inner member may be insulated using material forming the inner member, while wires in the groove may have additional insulation applied.

[0108] Directing attention now to FIG 6C, an alternative example is illustrated. The example illustrated in FIG 6C shows that the wires are molded into the inner member 606. In this example, embodiments coextrude or otherwise embed the wires 706 used to facilitate arcing for IVL procedures into the inner member 606 at the distal region of the IVL catheter 100. By embedding the wires 706, the inner member 606 itself can serve to insulate the wiring, allowing arcing regions to be defined / exposed, to form electrodes, by20 Docket No.: 23812.31.2Aetching (or other material removal procedures) performed on the inner member 606 at exposed points 612. Such construction may allow a partial cylindrical electrode member, which is a larger electrode structure, to be omitted, which can reduce crossing profile relative to certain embodiments (such as those in FIGs 6A, 7A, and 8A) and provide preferred deliverability and pushability characteristics for the catheter. The inner member 606 itself can perform the function of holding / retaining the wires 706, which is performed by the partial cylindrical electrode member in the other designs.

[0109] Directing attention now to FIG 6D, an alternative example is illustrated. In this example, the wires 706 are coextruded in a spiraled manner in the inner member 606. In the example illustrated openings at exposed points 604 are made to expose the wires 706. In some embodiments, the exposed points 604 are at different rotational positions with respect to each other. This allows for arcing at different rotational positions about the catheter IVL 100.

[0110] In the examples illustrated in FIGs 6C and 6D, the exposed points 612 of the inner member 606 are shown at different longitudinal locations. If the wires 706 remained intact, arcing would likely only occur at one of these longitudinal locations, the location with the least resistance. To achieve arcs at different longitudinal locations, cuts in the wire at the exposed points 612 (to define in-series arcing regions) may be introduced after the coextrusion process. Where cuts are implemented, the wire can comprise a material resistant to degradation during arcing, such as gold, platinum iridium, and / or other materials. In some embodiments, the wires 706 may be electroplated or otherwise have degradation resistant materials applied at the exposed points and wire cut locations.

[0111] Alternatively, as illustrated in FIG 6E the wires 706 may be bridging wires that are adjacently arranged within the inner member 606 so as to define arcing regions at exposed points. This arrangement is particularly novel inasmuch as the wires are embedded into the inner member 606 as opposed to embodiments that dispose the wires directly on an inner member or embodiments that place the wires on flex circuits which are then wrapped around an inner member. Some embodiments implement a longitudinal overlap region between adjacent wires to accommodate wire degradation.

[0112] While not shown in FIGs 6B, 6C, 6D, and 6E, embedding the wires and electrodes in the inner member 606 creates space to add additional wires such as those shown in FIGs 8B, 9B, 9C, and 9D to implement the axial firing emitter 808. Thus, the embodiments shown in FIGs 6B, 6C, 6D, and 6E have novelty over other embedded and coextruded wiring system in that they further facilitate and may include additional wiring21 Docket No.: 23812.31.2Anot shown for an axial emitter at the distal tip of the IVL catheter.

[0113] Referring to FIG. 9A, a sectional view of a distal tip portion of an IVL catheter is shown in accordance with an embodiment. The axial-firing emitter 808 at the distal end 804 of the catheter shaft 106 may be outside of the balloon interior 806 and, in an embodiment, exposed to blood flow within the vessel 102. In an embodiment, however, the axial-firing emitter 808 may be at least partially contained within the catheter tip 602 to provide control over the ambient conditions within which the acoustic waves are generated. For example, the catheter tip 602 can include a enclosure member 902 distal to the axial-firing emitter 808, and the axial-firing emitter 808 can emit short pulses into the enclosure member 902. The catheter tip 602 may be shaped and sized to facilitate delivery and shockwave generation. For example, the catheter tip 602 can have an outer dimension equal to or less than, e.g., 75% of, an outer dimension of the folded balloon. The tip shape may enhance shockwave delivery. For example, the tip shape may be conical, elliptical, or parabolic, as described herein, to direct the generated energy distally.

[0114] The enclosure member 902 can, during operation of the axial-firing emitter 808, be filled with the emitter bathing fluid to support acoustic wave generation. For example, the enclosure member 902 may be filled with an electrolyte during electrode activation. In an embodiment, the fluid is delivered by the fluid supply subsystem of the IVL control system 204 and can include saline. By way of example, the fluid may include a mixture of 50 / 50 saline and contrast to create a conductive fluid for the electrical spark to form within. The fluid supply subsystem (or the fluid pump 202) can deliver a bolus of the fluid into the enclosure member 902 through a fluid supply lumen 904 in fluid communication with the enclosure member 902.

[0115] The fluid supply lumen 904 can include channels, cavities, and spaces within which the electrolytic fluid is delivered. In an embodiment, the fluid supply lumen 904 includes a guidewire lumen 702 of the catheter shaft 106. The guidewire lumen 702 can be a channel within the inner member 606 of the catheter shaft 106 through which the guidewire 103 is passed during device tracking. In an embodiment, the fluid can be introduced through the guidewire lumen 702 around the guidewire 103. More particularly, the fluid can be introduced through the guidewire lumen 702 connector 504 on the hub 302, or through a rotating hemostatic valve attached to such a connector. Fluid can convey longitudinally through the guidewire lumen 702 into the enclosure member 902.

[0116] In an embodiment, the enclosure member 902 is in fluid communication with the interior 806 of the balloon 104. For example, a fluid supply hole 908 may be formed22 Docket No.: 23812.31.2Ain a section of the inner member 606 contained within the interior 806 to allow fluid to pass from the interior 806 into the guidewire lumen 702. The fluid supply hole 908 can convey inflation fluid, which is delivered into the balloon 104 to perform balloon inflation, toward the enclosure member 902. Accordingly, the enclosure member 902 can be filled with the electrolytic fluid during balloon inflation. By placing the axial-firing emitter 808 in fluid communication with the balloon 104, the electrolytic fluid can be used to inflate the balloon 104 and wet the axial -firing emitter 808 at the same time. The dual function can eliminate the need for dedicated lumens, e.g., two lumens, to independently inflate the balloon 104 and wet the emitter 808 during spark generation.

[0117] The fluid supply lumen 904 may include a flush tube 910 that is dedicated to conveying fluid toward the enclosure member 902. The flush tube 910 can extend longitudinally along the inner member 606 of the catheter shaft 106. The flush tube 910 can have a proximal tube end fluidically coupled to the fluid supply subsystem, and a distal tube end terminating within the catheter tip 602. Accordingly, electrolytic fluid can be carried through the flush tube 910 to fill the enclosure member 902 in the catheter tip 602.

[0118] The fluid supply lumen 904 can convey fluid into the enclosure member 902, however, passage of the fluid downstream into the vessel 102 may be blocked or restricted by an end cap 912 of the catheter tip 602. The catheter tip 602 can include the end cap 912 distal to the axial-firing emitter 808. For example, the end cap 912 can include a wall extending transverse to the longitudinal axis 802 of the catheter shaft 106, spanning laterally between sidewalls of the catheter tip 602. More particularly, the annular sidewalls of the catheter tip 602 and the end cap 912 can contain and define the enclosure member 902 distal to the inner member 606 and / or the axial-firing emitter 808.

[0119] In an embodiment, the end cap 912 includes a guidewire port 914. The guidewire port 914 can include a hole extending axially through the end cap 912. The hole can be axially aligned with the guidewire lumen 702 of the inner member 606. Accordingly, the guidewire 103 may pass longitudinally through the guidewire port 914 and the guidewire lumen 702 to allow the IVL catheter 100 to be tracked distally over the guidewire to a target anatomy.

[0120] The end cap 912 can be acoustically transparent, e.g., nominally acoustically transparent, and durable. The acoustic transparency of the end cap 912 can allow shockwaves to pass forward from the enclosure member 902 toward an adjacent lesion 108. A durable material can be used for the end cap 912 to avoid degradation from propagating wave energy. For example, the catheter tip 602 can be placed adjacent to a23 Docket No.: 23812.31.2Achronic total occlusion and, by activating the axial-firing emitter 808, short pressure pulses can be delivered through the end cap 912 into the occlusion to break up calcifications. The pressure pulses can transmit through the end cap 912 without damaging the end cap material. As described below, the forward-fired waves may be focused by focusing elements, to direct the acoustic waves through the end cap 912 and enhance treatment of the lesion 108.

[0121] Referring now to FIG. 9B, a perspective view of another example of a distal tip portion of an IVL catheter is shown. In this example, the axial firing emitter 808 near the distal end 804 of the catheter shaft is formed by two wires 906 spaced such that an arc can occur between the two wires 906. In some embodiments, the wires 906 may be embedded in the inner member 606.

[0122] FIG. 9B further illustrates a guidewire lumen 702.

[0123] FIG. 9B further illustrates a fluid supply lumen 904 that can covey fluid from the fluid supply subsystem of the IVL control system 204 to the axial firing emitter 808 and the enclosure member 902 to facilitate administration of IVL lithotripsy in an axial firing direction. The enclosure member may be a semiflexible material that holds fluid to facilitate the electrical arc. The enclosure member 902 may slightly expand, or not expand, but does not expand to the same degree that the ballon 104 expands. The enclosure member 902 may be made of a relatively thin but strong material, such as nylon or a nylon similar material. In some embodiments, the guidewire lumen 702 passes through the enclosure member 902 and is sealed from fluid with respect to the enclosure member 902.

[0124] In this example, the fluid supply lumen 904 is external to the guidewire lumen 702 such that fluid supplied to the enclosure member 902 does not need to be supplied in the same channel that contains the guidewire. FIG. 9B further illustrates a fluid return lumen 905 that removes fluid from the enclosure member 902 and returns it to the fluid supply subsystem of the IVL control system 204.

[0125] The various lumens shown could be formed as separate distinct parts that are later assembled. Alternatively, one or more of the various lumens could be formed as part of a multi lumen extrusion.

[0126] Referring now to FIG. 9C, an alternative embodiment of a distal tip portion of an IVL catheter is shown. This example shows a view looking at the front of the distal tip. This example shows how wires 906, guidewire lumen 702, fluid supply lumen 904 and fluid return lumen 905 could be coextruded in the inner member 606.

[0127] FIG. 9D illustrates an alternate geometry of a distal tip portion of an IVL24 Docket No.: 23812.31.2Acatheter. In this example, while the wires 906 are coextruded into the inner member 606, the guidewire lumen 702, fluid supply lumen 905, and fluid return lumen are formed separate from the inner member and assembled together as illustrated.

[0128] Referring to FIG. 10, a sectional view of a catheter tip of an IVL catheter is shown in accordance with an embodiment. The catheter tip 602 may restrict, but allow, fluid flow from the enclosure member 902 into the distal anatomy beyond the end cap 912. More particularly, the fluid may flow through the guidewire lumen 702 (e.g., from the balloon interior 806) into enclosure member 902 within the catheter tip 602 and out through the guidewire port 914 of the end cap 912. The flowing fluid can provide the ambient conditions within which spark generation can occur, as described below.

[0129] The fluid pathway through the guidewire lumen 702, the enclosure member 902, and the guidewire port 914 can be in fluid communication with the axial-firing emitter 808. The axial-firing emitter 808 may, for example, include an electrode pair, such as a wire pair, a plate pair, etc., to form a spark gap across which an electrical spark 1002 can form.

[0130] In an embodiment, the axial-firing emitter 808 includes several electrodes 1004 separated by the spark gap. For example, the electrodes 1004 can be arranged concentrically about the longitudinal axis 802 of the catheter shaft 106. Each electrode 1004 can include an annular structure, e.g., a tubular wall, extending about the longitudinal axis 802. The electrodes 1004 can have radial dimensions relative to the longitudinal axis 802. One of the electrodes 1004, e.g., a first electrode 1006, can have a radial dimension that is less than another one of the electrodes 1004, e.g., a second electrode 1008. Accordingly, the first electrode 1006 can be radially inward from the second electrode 1008.

[0131] The first electrode 1006 may be nested concentrically within the second electrode 1008. One or more dielectric layers or partial cylindrical electrode members can separate the electrodes from each other and / or from surrounding structures. For example, an insulating layer 1010 may be positioned between the first electrode 1006 and the second electrode 1008. Accordingly, the axial-firing emitter 808 can include a laminated partial cylindrical electrode member structure to generate the electrical spark 1002 that produces forward propagating shockwaves.

[0132] Directionality of the generated acoustic wave may be controlled in part by relative positioning of the electrodes. The first electrode 1006 can include a first distal edge 1012, e.g., a distalmost point on the electrode. Similarly, the second electrode 100825 Docket No.: 23812.31.2Acan include a second distal edge 1014, e.g., a respective distalmost point. A relative alignment of the edges may affect a path of the electrical spark 1002 when it forms and a containment of the resulting acoustic wave. For example, in an embodiment, the first distal edge 1012 of the first electrode 1006 is proximal to the second distal edge 1014 of the second electrode 1008 to cause the electrical spark 1002 to form between the distalmost point on the first electrode 1006 and an inward facing wall of the second electrode 1008. The electrical spark 1002 can therefore form inside the second electrode 1008 because the first electrode 1006 is recessed. The nominally rigid and metallic second electrode 1008 can be acoustically reflective and may tend to contain the expanding acoustic wave. More particularly, the expanding acoustic wave can be contained and directed forward within the enclosure member 902.

[0133] In an embodiment, the electrodes can connect to the wires 706 extending along the catheter shaft 106. The wires 706 can deliver electrical signals, e.g., voltage, to activate the axial-firing emitter 808 and cause the electrical spark 1002 to form. For example, a first wire can connect to the first electrode 1006 and a second wire can connect to the second electrode 1008. An electrical potential between the wires can be varied by the control handle 206 in communication with the IVL control system 204 to cause discharge between the electrodes through the electrolytic fluid within the enclosure member 902. Accordingly, the electrical spark 1002 can form and produce shockwaves that propagate forward through the end cap 912 to the lesion 108, e.g., into a calcified occlusion in the vessel 102 against which the end cap 912 is placed.

[0134] Referring to FIG. 11, a sectional view of a catheter tip of an IVL catheter is shown in accordance with an embodiment. The catheter tip 602 may entirely block fluid flow from the enclosure member 902 into the distal anatomy beyond the end cap 912, and may instead contain the fluid within the enclosure member 902. More particularly, the fluid may flow through the flush tube 910 into the enclosure member 902 within the catheter tip 602. The enclosure member 902 can be contained between the tip sidewall, the inner member 606, and the end cap 912. For example, the enclosure member 902 can include an annular space between the inner member 606 and the annular sidewall of the catheter tip 602. The annular space can be filled by the fluid, and the end cap 912 can prevent loss of the fluid into the distal anatomy. Accordingly, the contained fluid within the enclosure member 902 can provide the ambient conditions within which spark generation can occur, as described below.

[0135] The axial-firing emitter structure may be similar to the structure described26 Docket No.: 23812.31.2Aabove with respect to FIG. 10. More particularly, the axial -firing emitter 808 can include the first electrode 1006 separated from the second electrode 1008 by an insulating layer 1010. In an embodiment, however, the electrodes may have arc section or broken partial cylindrical electrode member structures such that a portion of the cross-section taken through the electrodes includes a gap. The gap in FIG. 11 is located at a bottom region of the annular space formed by the enclosure member 902. In an embodiment, the flush tube 910 can extend through the catheter tip 602 into the gap and can deliver fluid distally into the annular space.

[0136] The electrodes can discharge within the encapsulated fluid in the catheter tip 602. More particularly, the electrodes can be energized by the wires 706 to cause the axial- firing electrode 808 to generate the electrical spark 1002 that produces the forward propagating waves. The waves can propagate through the annular space that extends along an outer surface of the inner member 606. The waves may pass forward through the acoustically transparent end cap 912 into the adjacent anatomy. Given that the enclosure member 902 is contained outside of the guidewire lumen 702, the guidewire 103 may optionally remain in place during activation of the axial-firing emitter 808.

[0137] Referring to FIG. 12, a schematic view of a catheter tip of an IVL catheter having a refractive focusing element is shown in accordance with an embodiment. The catheter tip 602 can act as an acoustic lens to direct energy forward toward an adjacent lesion 108. More particularly, in an embodiment, the catheter tip 602 includes a refractive focusing element 1202 to direct acoustic waves through the end cap 912.

[0138] The energy directed by the refractive focusing element 1202 may be shockwaves generated by the electrical discharge emitter pairs 604 described above. Alternatively, the axial-firing emitter 808 can include an optical emitter, and the refractive focusing element 1202 can include an optical focusing element either separate or effected as an end treatment on an optical fiber.

[0139] In the case of acoustic wave generation by the axial-firing emitter 808, the focusing element can shape the acoustic waves. The pressure pulse waves generated by the axial-firing emitter 808 can expand nominally spherically from the emitter. The pressure of the wave front may decrease as the square of the distance from the emitter. If the emitter 808 is separated from lesion 108 by the more-distal elements of the catheter, therefore, the energy directed into the lesion 108 may have minimal therapeutic effect. The focusing element, e.g., the refractive focusing element 1202, however, can collimate or focus the wave to direct the wave forward into the lesion 108 with higher intensity.27 Docket No.: 23812.31.2A

[0140] In an embodiment, the refractive focusing element 1202 can include an acoustic lens located distal to the enclosure member 902. Furthermore, the refractive focusing element 1202 may be proximal to the end cap 912, or may be integrally formed as the end cap 912. In either case, the refractive focusing element 1202 can provide a converging acoustic lens, which is illustrated as a bi-concave lens but it will be appreciated that the shape is material dependent, to focus the diverging spherical waves into forward-directed waves. The refractive focusing element 1202 can have a different, e.g., lower or higher, acoustic impedance than the fluid in the enclosure member 902, and may be shaped to cause the waves to propagate forward in a predetermined manner. The combination of material and shape can perform the refractive action to focus the acoustic waves. The forward propagation may be as a collimated wave 1204, or as a focused wave 1206. The collimated wave 1204 (depicted by solid arrows) can propagate substantially forward to remain within a cross-sectional area equal to that of the end cap 912 over a length, e.g., 5 to 20 mm. The focused wave 1206 (depicted by dotted arrows) can propagate to a focal point at a distance along the longitudinal axis, e.g., 5 to 20 mm in front of the end cap 912.

[0141] The collimation and / or focusing of the wavefront can depend on a longitudinal distance between the axial-firing emitter 808, e.g., the discharging electrodes generating the electrical spark or the optical fiber emitting the optical beam. In an embodiment, the longitudinal distance can be controlled to adjust the focal point of the wavefront distal to the end cap 912. More particularly, the refractive focusing element 1202 may be movable, e.g., translatable, along the longitudinal axis 802 relative to the axial -firing emitter 808. The distance may, for example, be changed during a procedure by actuating a lever of the control handle 206 to cause a pull / push wire to slide the refractive focusing element 1202 longitudinally relative to the emitter that is fixed relative to the catheter shaft 106. Alternatively, the emitter may be moved by such an operation. In any case, the movement can cause the wavefront energy to be directed to a varying location distal to the end cap 912. As a result, the catheter shaft 106 may be fixed within the vessel 102 while moving the wavefront energy focal point longitudinally in the forward-facing direction. The energy may therefore be controlled to allow a progressive drilling operation that moves the focal point through a calcified lesion 108 and breaks up the lesion along a longitudinal path that the IVL catheter 100 can subsequently be tracked through.

[0142] Referring to FIG. 13, a schematic view of a catheter tip of an IVL catheter having a reflective focusing element is shown in accordance with an embodiment. Wave energy may be focused by reflection. In an embodiment, the catheter tip 602 includes a28 Docket No.: 23812.31.2Areflective focusing element 1302 to direct the acoustic waves through the end cap 912. The reflective focusing element 1302 can include an acoustically reflective reflector positioned adjacent to the axial -firing emitter 808, e.g., the electrode, such that shockwaves generated by the electrode reflect from the reflector in the distal direction.

[0143] In an embodiment, the reflective focusing element 1302 can include an acoustic mirror located proximal to the enclosure member 902. The reflective focusing element 1302 can be shaped to cause the spherically expanding wavefront from the emitter pairs 604 to be reflected in a forward direction through the end cap 912. The direction of propagation of the forward-focused wavefront can depend on a shape of the reflective focusing element 1302. For example, the reflective focusing element 1302 can include a rigid, acoustically reflective material shaped to have a parabolic or an elliptical profile. The parabolic profile can collimate the energy into the collimated wave 1204 that propagates in the substantially parallel manner described above. Alternatively, the elliptical profile can focus the energy into the focused wave 1206 that impinges on a focal point distal to but near the end cap 912. The forward-propagating wavefront may therefore be used to break up calcifications against which the catheter tip 602 is placed.

[0144] Referring to FIG. 14, a cross-sectional view of a pressure pulse directing balloon of an IVL catheter is shown in accordance with an embodiment. Directional energy delivery of the IVL catheter 100 may be achieved by a balloon design that directs wave energy to a target location in the radial direction 821 relative to the longitudinal axis 802. More particularly, the balloon 104 can direct wave energy in a predetermined direction. For example, the wave energy of the radial-firing emitters 814 can be directed toward an eccentric calcified lesion 108 that is not uniformly distributed about the circumference of the vessel wall 110. The wave energy may propagate at a particular angle, or within a particular angle range, relative to the longitudinal axis 802 of the IVL catheter 100 toward the lesion 108. The focused radially-directed energy can disrupt the non-uniform lesion 108 without losing energy through healthy tissue circumferentially offset from the lesion 108. More particularly, rather than wave energy being dispersed in directions that do not contribute to calcification disruption, in certain anatomical situations, the IVL catheter 100 can be used to target predetermined vascular regions for disruption with focused energy.

[0145] In an embodiment, the balloon 104 includes a balloon wall 1402 circumferentially surrounding the one or more radial-firing emitters 814. The balloon wall 1402 may have several wall sections with varying degrees of acoustic transparency. For29 Docket No.: 23812.31.2Aexample, a first wall section 1404 can be circumferentially offset from a second wall section 1406, and the first wall section 1404 may be more transmissive of acoustic waves than the second wall section 1406. Accordingly, as illustrated by arrows, the acoustic waves generated by the radial-firing emitter 814 can tend to propagate through the first wall section 1404 rather than the second wall section 1406. An energy density adjacent to the first wall section 1404 may therefore be higher than an energy density adjacent to the second wall section 1406. The first wall section 1404 may therefore be expanded against an eccentric calcified lesion 108 to target the lesion by activation of the radial-firing emitter 814.

[0146] The difference in transmissivity of the balloon wall sections can be achieved in various manners. For example, the first wall section 1404 may have a different density than the second wall section 1406. In an embodiment, the material of the second wall section 1406 is denser than the material of the first wall section 1404. Such density difference can be caused by material selection in a balloon tubing extrusion process, e.g., a balloon tubing have a striped structure of various material densities. Longitudinal stripes of the tubing may include materials of different characteristics, such as differing elastic modulus. Alternatively, the density may be caused by post-processing, such as a heat treating or curing process during balloon manufacturing that cause the second wall section 1406 to densify at a different rate or to a different degree than the first wall section 1404. In any case, the difference in density can cause the generated waves to reflect from the second wall section 1406 and travel through the first wall section 1404 to the targeted lesion 108.

[0147] Other material characteristics of the wall section can correspond to acoustic transmissivity. In an embodiment, the balloon compliance of the wall sections correlates to transmissivity. For example, the first wall section 1404 may be more or less compliant than the second wall section 1406. Such differences in compliance can be provided through the balloon forming process. The wall sections having different compliances can interact with acoustic waves differently. Accordingly, acoustic waves can propagate non- uniformly through the variable compliance balloon wall 1402, e.g., preferentially through one of the wall sections.

[0148] Referring to FIG. 15, a cross-sectional view of a pressure pulse directing balloon of an IVL catheter is shown in accordance with an embodiment. In an embodiment, a reflective layer 1504 can be placed over the second wall section 1406 to reflect energy toward the first wall section 1404. The first wall section 1404 and the30 Docket No.: 23812.31.2Asecond wall section 1406 may include a base layer 1502, e.g., a standard balloon wall formed by balloon blowing. The reflective layer 1504 can be disposed on the base layer 1502 over a portion of the balloon wall 1402. For example, the second wall section 1406 can include the reflective layer 1504 on the base layer 1502, and the first wall section 1404 may have an uncovered base layer 1502.

[0149] The reflective layer 1504 can be acoustically opaque, and the base layer 1502 can be acoustically transparent. Accordingly, when wave energy from the radial-firing emitter 814 propagates radially outward from the longitudinal axis 802, the wavefront can reflect from the reflective layer 1504 covering the second wall section 1406 and through the base layer 1502 of the first wall section 1404. A lesion adjacent to the first wall section 1404 may therefore be targeted.

[0150] The reflective layer 1504 may be disposed on the base layer 1502 during the extrusion of the balloon tubing. For example, the balloon tubing may include a dual -wall extrusion in which an outer wall is reflective. The outer wall may then be removed during, before, or after balloon blowing to expose the base layer 1502 under the reflective outer wall. For example, an excimer laser may ablate the reflective layer 1504 to remove it from the base layer 1502. Accordingly, the reflective layer 1504 may be integral to the balloon tubing used to form the balloon 104.

[0151] The reflective layer 1504 may be added to the base layer 1502 during the balloon forming process. For example, a reflective coating can be deposited, e.g., in a vacuum deposition process, on the base layer 1502. Alternatively, the reflective layer 1504 can include a thin film that is adhered to the base layer 1502 by a bond. Accordingly, the reflective layer 1504 can be a separate material that is added to the base layer 1502 after balloon blowing.

[0152] Referring to FIG. 16, a cross-sectional view of a pressure pulse directing balloon of an IVL catheter is shown in accordance with an embodiment. A difference in transmissivity may derive from a thickness of the respective balloon wall sections. In an embodiment, the first wall section 1404 has a different thickness than the second wall section 1406. For example, the first wall section 1404 can be thinner than the second wall section 1406. The difference in thickness may be caused by extruding the balloon tubing to have an eccentric lumen and, therefore, a varying wall thickness. When the balloon tubing is expanded in a balloon blowing process, the thickness variation may persist. The difference in thickness can create a distributed reflection coefficient within the balloon wall 1402 that can cause energy to reflect in a predetermined manner. More particularly,31 Docket No.: 23812.31.2Athe wave energy can preferentially pass through the first wall section 1404 into an adjacent lesion.

[0153] Referring to FIG. 17, a cross-sectional view of a pressure pulse directing balloon of an IVL catheter is shown in accordance with an embodiment. Variation in wave energy propagation may result from fluid distribution within the balloon 104. In an embodiment, the balloon 104 includes one or more balloon septa 1702 to divide a balloon volume 1704 into several balloon chambers 1706. The balloon volume 1704 can, for example, be an entire volume of space contained by a circular outer profile of the balloon 104. By contrast, the balloon chambers 1706 can have profiles that segment the balloon volume space. For example, the balloon 104 may include four balloon septa 1702 equally spaced about the longitudinal axis 802 and, therefore, the balloon volume 1704 may be partitioned into four balloon chambers 1706 that have quarter-circle segment profiles. It will be appreciated that any number of balloon septa 1702 may be used to segment the balloon profile. For example, eight balloon septa 1702 around the longitudinal axis 802 can segment the profile into eight balloon chambers 1706.

[0154] The balloon septa 1702 may be individually formed. In an embodiment, the balloon 104 profile is an accumulation of balloon bladders that are distributed about the catheter shaft 106 and constrained by an outer balloon wall 1402. More particularly, the balloon bladders can be inner balloons inside of an outer balloon. The outer balloon can constrain the inner balloon bladders and maintain them in a uniform distribution about the longitudinal axis 802. Adjacent sidewalls of the inner balloons can provide the balloon septa 1702.

[0155] The balloon septa 1702 may be integrally formed. In an embodiment, the balloon tubing can include a multi-lumen extrusion. For example, several lumens may be distributed about a central axis of the tubing during extrusion. The tubing may be expanded in a balloon blowing process to form the balloon 104 having balloon septa 1702 between the balloon chambers 1706. More particularly, the balloon chambers 1706 can be formed from the expanded tubing lumens during the blowing process.

[0156] Preferential propagation of wave energy through the multi-chambered balloon 104 can depend on an inflation fluid used to expand the balloon 104. For example, one or more balloon chambers 1706 may be contained radially within the first wall section 1404 of the balloon 104. Similarly, one or more balloon chambers 1706 may be contained radially within the second wall section 1406. The balloon chambers 1706 contained by the first wall section 1404 can be filled with a first inflation fluid, and the balloon chambers32 Docket No.: 23812.31.2A1706 contained by the second wall section 1406 can be filled with a second inflation fluid. In an embodiment, the first inflation fluid is more transmissive to acoustic waves than the second inflation fluid. For example, the first inflation fluid may be more acoustically transparent than the second inflation fluid. The acoustic transparency can correspond to a density of the inflation fluid. For example, the first inflation fluid may be less dense than the second inflation fluid. When the radial-firing emitter 814 generates acoustic waves, the waves may reflect from the balloon chambers 1706 filled with the second inflation fluid and preferentially travel outward through the first inflation fluid and the first wall section 1404. Accordingly, the wave energy can be directed in a particular radial direction 821, e.g., toward a target lesion 108.

[0157] The balloon chambers 1706, which can be circumferentially separated about the longitudinal axis 802, may be independently expanded. For example, a first chamber may be in fluid communication with a first lumen to receive the first inflation fluid, and a second chamber may be in fluid communication with a second lumen to receive the second inflation fluid. Alternatively, several balloon chambers 1706 may be collectively coupled to a same inflation lumen to receive a same inflation fluid, e.g., several balloon chambers 1706 can receive the second inflation fluid. Accordingly, the balloon chambers 1706 can be filled with an appropriate inflation fluid to control energy propagation through the balloon interior 806 toward the target tissue.

[0158] Referring to FIG. 18, a cross-sectional view of a pressure pulse directing balloon of an IVL catheter is shown in accordance with an embodiment. The balloon wall 1402 circumferentially surrounding the one or more radial-firing emitters 814 may have a non-round profile to cause wave energy to transmit non-uniformly out of the balloon interior 806. For example, a wall profile 1802 of the balloon wall 1402 may be elliptical. The wall profile 1802 shape can be formed in the balloon blowing process, e.g., by using an elliptical mold shape. Similar to the elliptical (or parabolic) reflective focusing element 1302 described above, the elliptical shape of the balloon wall 1402 can cause wave energy to collimate or focus in a particular direction. Optionally, the reflective layer 1504 may be placed over a portion of the elliptically shaped balloon wall 1402 to cause energy to be reflected in a collimated manner. More particularly, the radially fired wavefront can propagate in a collimated or focused path outward toward a particular point in the target lesion 108.

[0159] Radial directionality of emitted energy may also be influenced by electrode design. For example, coating the electrodes with platinum can enhance the efficiency of wave33 Docket No.: 23812.31.2Areflection directionally. This can be accomplished by designing electrodes with a greater acoustic impedance mismatch between the electrode material and the coating, such as platinum. A higher impedance mismatch will result in more wave reflection. Additionally, shaping the electrode into a conical form, a hollow form, or a porous form, and applying platinum coating only to the inner diameter can facilitate more localized wave transfer.

[0160] Other methods to achieve directionality based on electrode design can include the use of commercially available Drawn Filled Tubing (DFT) materials. The shape of the electrodes, such as using a D-shaped electrode or an electrode that is thicker on one side versus another side, or a hexagonal shape instead of round shape, and alternating electrodes with varying thickness, may be used. In any case, the emitted wave energy may preferentially propagate in a particular radial direction, which can be oriented toward a target lesion 108 during balloon inflation to selectively treat the lesion as compared to other regions of the vessel wall 110.

[0161] Referring to FIG. 19, a flowchart of a method of treating a calcified lesion using an IVL catheter is shown in accordance with an embodiment. FIGS. 20-23 are pictorial views of operations of the method. Accordingly, FIGS. 19-23 will be alternately referred to in the following description.

[0162] Referring to FIG. 20, the guidewire 103 can be delivered through a body lumen 2002 to a calcified lesion 2004. The calcified lesion 2004 may, for example, include a chronic total occlusion of a coronary or peripheral artery. The guidewire 103 may cross the calcified lesion 2004. However, in some instances, the chronic total occlusion may not have a channel that supports guidewire crossing, and progression of a distal tip of the guidewire 103 may be blocked by the occlusion.

[0163] Referring to FIG. 21, at operation 1902, the IVL catheter 100 can be delivered over the guidewire 103 to the calcified lesion 2004. The pathway traversed by the guidewire 103 may be too narrow for the IVL catheter 100 to cross. For example, the guidewire 103 through the occlusion may extend through a microchannel in the chronic total occlusion that cannot be crossed by the IVL catheter 100 without risk of damage to the uninflated balloon 104.

[0164] Referring to FIG. 22, at operation 1904, the axial-firing emitter 808 of the IVL catheter 100 is activated to emit acoustic waves in the axial direction 812 into the calcified lesion 2004. More particularly, the acoustic waves can travel along the longitudinal axis 802 in the direction of the guidewire 103 into the lesion 108. The axial-firing emitter 80834 Docket No.: 23812.31.2Ais outside of the balloon 104, e.g., distal to the balloon 104, and can therefore be positioned closer to (or partially within) the occlusive lesion 108. By contrast, emitters 814 within the balloon 104 may be restricted from passing into the lesion 108 and would be unable to deliver adequate energy to break up the lesion 108, or could heat and damage the unexpanded balloon 104 that would be squeezed against the lesion 108. The axial-firing emitter 808, however, can generate a forward propagating wave, e.g., via discharging electrodes, which disrupts the calcified lesion 2004 without impinging on or harming the balloon 104.

[0165] Optionally, the guidewire 103 can be retracted during emitter activation. For example, the guidewire 103 can be retracted proximal to the axial-firing emitter 808 before activating the axial-firing emitter 808. Guidewire retraction can prevent sparking to the guidewire 103 itself, e.g., in the embodiment illustrated in FIG. 10, and may be unnecessary when the emitter pairs 604 is insulated from the guidewire lumen 702, e.g., in the embodiment in FIG. 11. In any case, the wavefront can propagate forward through the end cap 912 into the calcified lesion 2004 to treat the lesion. In alternative embodiments, the guidewire 103 may be non-conductive or insulated.

[0166] At operation 1906, the IVL catheter 100 and / or guidewire 103 may be advanced through the calcified lesion 2004. More particularly, the calcified lesion 2004 can be disrupted to properly position the balloon 104 within the lesion 108 for continued treatment. The IVL catheter 100 can be advanced through the lesion while the balloon 104 is deflated. For example, the catheter tip 602 and balloon 104 can wedge through the chronic total occlusion to place the radial -firing emitters 814 radially inward from the calcified lesion 2004.

[0167] Referring to FIG. 23, at operation 1908, one or more of the radial-firing emitters 814 can emit acoustic waves in the radial direction 821 into the calcified lesion 2004. The balloon 104 may be inflated to press the balloon wall 1402 against the occlusive tissue. The emitters 814 may then be activated to disrupt the tissue. Balloon inflation and emitter activation can occur sequentially or in a stepwise manner, e.g., sending pulsed waves to disrupt the lesion 108 before and after inflating the balloon 104 to expand the lesion 108.

[0168] The radially emitted wave energy may be unfocused. For example, the acoustic waves can travel uniformly outward from the longitudinal axis 802 to disrupt the calcified lesion 2004. Alternatively, wave energy may be radially directed or focused according to the embodiments described with respect to FIGS. 14-18 above. For example, several35 Docket No.: 23812.31.2Aballoon chambers 1706 of the balloon 104 can be filled with respective fluids having different densities, and the wave energy can propagate preferentially through one or more of the balloon chambers 1706 into adjacent tissue having the target lesion 108. Accordingly, the radial action of the IVL catheter 100 may continue treatment of the lesion 108, without exchanging the IVL catheter 100 having the forward-firing emitter 808 with a second IVL catheter 100 having the radial-firing emitter 814, because the emitters are combined into a universal device.

[0169] Referring to FIG. 24, a schematic of a control circuit of an electrode controller is shown in accordance with an embodiment. An electrode controller 2400 having an electrical circuit 2402 for use in selective firing of the emitters, e.g., the electrode pairs 820, 822, and 824, can include relays KI, K2, K3, K4, K5, and K6. The relays can activate the electrode pairs, some of which may be contained in the enclosure 104’ or balloon, e.g., radial-firing emitters, and at least one of which may be distal to the enclosure 104’, e.g., the axial-firing emitter. Each electrode pair can have two contacts with corresponding supply conductors in the IVL catheter 100. The electrode controller 2400 can have a capacitor bank 2403 that can be charged to a desired high voltage (HV), a trigger circuit 2404, and the several relays K1-K6 that connect the conductors (A-F) to either a high voltage rail 2405 or a return switched ground 2406 (the trigger circuit 2404 going to GND 2407).

[0170] The trigger circuit 2404 can comprise a transistor 2409 provided along a conductor running to GND 2407 from the switched ground 2406 for selective firing of the electrode pairs, and the transistor 2409 can be operatively coupled with a trigger (electrical, mechanical, and / or otherwise) that is operable by a user of the high energy acoustic lithotripsy catheter system. Conductors A, B, C, D, E, and F are schematically noted as coupled with the electrode pairs as basically three circuits in parallel. The electrode pairs provide gaps for a spark to be generated, as described above. A selectively controllable high voltage circuit includes: a conductor coupled to the HV side of the capacitor bank 2403, a high voltage rail 2405 coupled to the HV side of the capacitor bank 2403, an input terminal of each of the relays KI, K3, and K5 (as in the illustrated embodiment of FIG. 24) coupled to the HV side of the capacitor bank 2403, conductors A, C, and E each coupled to a corresponding output terminal of a relay KI, K3, and K5 respectively, a first electrode of each of the electrode pairs 820, 822, 824 coupled to the conductors A, C, and E respectively, conductors B, D, and F coupled to a second electrode of each of the electrode pairs 820, 822, 824 respectively, an input terminal of each of the relays K2, K4,36 Docket No.: 23812.31.2Aand K6, coupled to conductors B, D, and F respectively, an output terminal of each of the relays K2, K4, and K6, coupled to the switched ground 2406, and the trigger circuit 2404 configured to selectively, electrically couple the switched ground 2406 and GND 2407. As above, the capacitor bank 2403 is charged and then can discharge a high voltage pulse under control of the trigger circuit 2404 when the trigger circuit 2404 closes the high voltage circuit and certain of the relays illustrated are actuated.

[0171] As an example of selective connecting of electrode pairs to fire, if prior to triggering a high voltage pulse, relays KI and K2 are closed connecting conductors A and B through the proximal electrode pair 824 shown in FIG. 24, the proximal electrode pair 824 alone would fire. This same single electrode pair firing could occur similarly through the middle electrode pair 822 as coupled by conductors C and D and by closing relays K3 and K4. Likewise, the distal, axial-firing electrode pair 820 can connect conductors E and F by closing relays K5 and K6. It is also contemplated that any of the plurality of electrode pairs could be fired at the same time by controlling the appropriate relays between select conductor pairs and the electrode pairs, as in the present example, each electrode pair is fired as a separate parallel electrical circuit. This can be done with any number of electrode pairs coupled in parallel, although potentially with more than one high voltage pulse generator, as described below.

[0172] It is also contemplated that one or more additional relays, and conductors can be added to the circuit 2402 in addition to the relays K1-K6. For example, a relay K7 can be coupled between conductors B and C in the electrode controller 2400, and when the relay K7 is closed along with relays KI and K4, but with relay K3 open, the proximal and middle electrode pairs 824 and 822 respectively would be coupled in series. Both the proximal and middle electrode pairs 824 and 822 would fire at the same time.

[0173] In another example, connecting distal ends of conductors B and C can be done to arrange the proximal and middle electrode pair in series. Like the parallel circuits described above, closing relays KI and K2 is performed to fire electrode pair 824 only. Likewise, closing relays K3 and K4 will fire the middle electrode pair 822 alone. However, closing just relays KI and K4 would fire both the proximal electrode pair and middle electrode pair 824 and 822 in series.

[0174] It is also contemplated that connecting conductor ends B to C and B to E and C to E, etc. could be done, for example, in the electrode controller 2400, and then select relays can be closed to fire each electrode pair by itself, all three together, or certain pairs.

[0175] Other combinations can also be created by adding relays to the electrode controller37 Docket No.: 23812.31.2A2400, whereby the high voltage current will travel to an electrode pair and back and then back out to another electrode pair, etc. to fire them simultaneously. Other permutations, including the making of additional cross-connections at the distal end, would also be possible.

[0176] With the schematic shown in FIG. 24, based on the use of two-position relays for relays K1-K7, all combinations of contiguous electrode pairs could be activated. As shown, non-contiguous electrode pair combinations (e.g., the proximal electrode pair 824 and the distal electrode pair 820) would not both fire because the electrode pairs would be in parallel. In one example, HV and GND can be coupled across the proximal electrode pair 824 using the first two relays KI and K2, and HV and GND can be coupled across distal electrode pair 820 using the last two relays K5 and K6. A breakdown of the fluid around a given electrode pair is a stochastic and non-repeatable process. Each time it takes a slightly different amount of time and the dynamics are slightly different. However, once a plasma channel forms, the voltage across the electrode pair drops close to zero. This means that once one electrode pair (such as the proximal electrode pair 824) breaks down, the voltage across a parallel coupled electrode pair (such as the distal electrode pair 820) will drop very low, and the parallel coupled distal electrode pair 820 will now fail to break down and cause an arc. In such an example, it would be somewhat random whether the proximal electrode pair 824 or the distal electrode pair 820 will fire, depending on other conditions, such as which electrode pair has a slightly narrower gap, or the like.

[0177] Referring to FIG. 25, a schematic of a control circuit of an electrode controller is shown in accordance with an embodiment. In order to fire non-contiguous electrode pairs, the schematics shown in FIGS. 25 and 27 provide circuit arrangement options to do so. In FIG. 25, adding plural "shorting relays" (abbreviated as SI and S2) are also provided that can be open or closed. The other relays KI, K2, K3, K4, and K5 can be set to various combinations of +HV, GND, or open. According to the schematic of FIG. 25, any of the 15 combinations of four electrode pairs (abbreviated as El, E2, E3, and / or E4) can be set to fire, and they will fire while being coupled in series. It will appreciated that four electrode pairs is provided by way of example, and the IVL catheter 100 may have fewer than four electrode pairs, e.g., three electrode pairs as shown in FIG. 24) or more than four electrode pairs. In any case, such a circuit arrangement uses 3 -position relays (HV, GND, or open) in all or most of the relays K1-K5 along with single pole, single throw (i.e., open / closed) shorting relays SI and S2.

[0178] Referring to FIG. 26, a truth table of the control circuit of FIG. 25 is shown in38 Docket No.: 23812.31.2Aaccordance with an embodiment. The truth table illustrates a 1 for an electrode pair set to fire and a 0 for an electrode pair not set to fire as well as the connections of the relays KI, K2, K3, K4, K5 to HV, GND, or open (no entry in the table), and the shorting relays SI and S2, where 1 is closed and no entry in the table is open.

[0179] Referring to FIG. 27, a schematic of a control circuit of an electrode controller is shown in accordance with an embodiment. In this circuit, two independent high-voltage sources HV1 and HV2 are provided, typically using two different isolated HV capacitor banks. This circuit uses three-position relays for K2 and K4 and two-position relays for KI and K5. The K3 relay is eliminated in favor of a permanent GND connection and / or the K3 relay is always set to GND. Having two separate HV sources has the disadvantages of greater cost and complexity and size, but has the advantage of not needing to be adjustable over as wide range of a range of voltages as the circuit in FIG. 25. To fire four electrode pairs in series would require higher voltage than to fire two. But according to this example circuit, only one or two (or zero) electrode pairs are fired from a given high volage capacitor bank (or other high voltage power supply). This arrangement also has an advantage over the "shorting relay" arrangement of FIG. 25 because the spark current only flows from the proximal console distally to the electrode pair(s) and proximally back to the console. In the shorting arrangement of FIG. 25, with a shorting relay closed, current potentially flows in two round trips from the proximal console distally to the electrode pair(s), proximally back to the console, from the console distally to the electrode pair(s) and proximally back to the console.

[0180] Referring to FIG. 28, a truth table of the control circuit of FIG. 27 is shown in accordance with an embodiment. Like FIG. 26, FIG. 28 shows how any combination of electrode pairs E1-E4 can be fired by controlling the position of the relays K1-K5, respectively, along with the plural high voltage circuits HV1 and HV2, which are isolated power supplies isolated from each other, for the plural high voltage supply circuit.

[0181] Referring to FIG. 29, a pictorial view of a graphical user interface of an IVL system is shown in accordance with an embodiment. A graphical user interface (GUI) 2900 can be used to control the IVL system 200. For example, the GUI 2900 may be displayed to a user by a display of the IVL control system 204 to allow the user to select GUI elements that control operation of the system. In an embodiment, the GUI 2900 includes an indicator light, such as an LED, for each electrode pair of the high energy acoustic lithotripsy system. For example, the GUI 2900 can include an activation element 2902 or indicator light corresponding to the axial-firing emitter 808, e.g., electrode pair39 Docket No.: 23812.31.2A820. Similarly, the GUI 2900 can include an activation element 2904, 2906 or indicator light corresponding to respective radial-firing emitter(s) 814, e.g., electrode pairs 822, 824. Each indicator light can include a designation identifier for one of the electrode pairs. A cardiologist or other physician can select specifically each electrode pair that is desired to be fired as such GUI 2900 is operatively electrically coupled with a control circuit, such as those described above and shown in Figs. 24, 25, and 27. For example, the user can select activation element 2902 at operation 1904 to activate the axial-firing emitter to emit acoustic waves in an axial direction into the calcified lesion. Similarly, the user can select activation element 2904 and / or 2906 at operation 1908 to activate one or more radial firing emitters to emit acoustic waves in a radial direction into the calcified lesion. As above, the selection of which electrode pairs are to be fired can be based on the position of the high energy acoustic lithotripsy balloon within a location within a vessel, which specific location can be determined by various imaging techniques. The GUI can comprise a touchscreen, or independent buttons, switches, or the like. Different colors may be included to indicate whether a particular electrode pair is “on” so as to be fired at a next high voltage pulse or “off.”

[0182] Referring now to FIGS. 30A-30D, additional examples of a catheter tip including both one or more axial-firing emitters and one or more radial or distally firing emitters are illustrated. In this example, an intravascular lithotripsy (IVL) device 3000 is shown. The IVL device 3000 is disposed at a distal end of a catheter shaft and includes a flex tip 3002, one or more lithotripsy emitters 3004 and 3008, and a balloon 104. In closed- balloon embodiments (see FIG. 30 A), the balloon 104 surrounds the lithotripsy emitters 3004, 3008 and is configured to retain a dielectric or conductive fluid during operation. In open-balloon embodiments (see FIGS. 30C-30D), the balloon defines an open flow path that permits continuous fluid exchange across the emitters.

[0183] The flex tip 3002 is configured to flex or steer selectively in one or more directions. In some embodiments, the flex tip 3002 includes one or more slots, notches, or grooves (collectively “slots”) formed therein — e.g., by laser cutting a solid tubular member — to form a flexible segment.

[0184] In some embodiments, four steering wires (although other numbers may be used) are disposed circumferentially around the elongate flexible member, each wire being anchored near or distal to the slotted region. Selective tensioning or compression of individual wires from a proximal handle produces bidirectional or omnidirectional deflection of the flex tip 3002. In alternative embodiments, a proximal control handle40 Docket No.: 23812.31.2Aincludes a rotatable deflection collar coupled to an internal deflection element extending along the shaft; rotation of the collar about its axis translates the control element axially, inducing curvature of the distal segment. Counter-rotation returns the segment toward neutral. A locking assembly may be provided to maintain a selected curvature during catheter manipulation or device exchange. Suitable steering mechanisms may be of the type used in commercially available steerable introducers or other equivalent deflection systems.

[0185] Steering or bending of the flex tip 3002 repositions the lithotripsy emitters 3004 and / or 3008 toward a target region such as a calcified lesion. By positioning an emitter within several millimeters of the target, the resulting acoustic shockwaves can deliver increased localized pressure — e.g., increases of 10-50 percent at 1-5 mm standoff — enhancing disruption of calcific deposits.

[0186] In the embodiment of FIG. 30 A, two different types of emitters are shown. A distal emitter 3008 is implemented as an axial-firing spark-gap disposed at the distal face of the flex tip 3002. Conductors extend from the IVL control system through the catheter shaft to the distal emitter. The distal emitter 3008 may include opposed or coaxially aligned electrode tips forming a spark gap of approximately 0.05-0.5 mm, energized at 0.5-5 kV to produce an axial acoustic shockwave.

[0187] Distal electrode materials may include one or more of platinum, palladium, tungsten, gold, or stainless steel to provide durability for extended discharge cycling. The electrodes may be insulated by dielectric sleeves of polyimide or PEEK, and the balloon fluid can serve as a thermal sink to dissipate heat. Such materials and configurations are particularly advantageous when the distal emitter 3008 is used for a large number of discharge cycles during treatment.

[0188] In other embodiments, the distal emitter 3008 may be designed for limited-use applications, for example when a small number of chronic total occlusions (CTOs) are encountered. In such cases, lower-cost or less durable electrode materials may be employed without significant performance loss.

[0189] While the distal emitter 3008 is depicted as a spark-gap formed by wire ends, other emitter geometries — for example ring-tip, coaxial, or recessed-tip configurations — may be employed to achieve the desired axial shockwave pattern.

[0190] Also shown in FIG. 30A, an emitter pair 3004 provides radial emission. Each pair may be implemented in the manner of other emitter pairs described herein (e.g., 604- 1, 604-2, etc.). Although one emitter is visible in the figure, a second, diametrically41 Docket No.: 23812.31.2Aopposed emitter is provided on the opposite side of the balloon. The number and arrangement of emitters can be varied; in some embodiments a single radial emitter or multiple circumferentially spaced emitters are provided.

[0191] The distal emitter 3008 and the emitter pair 3004 are independently controllable, allowing selective operation of axial-firing and radial-firing modes. Each emitter or emitter group may be connected to a dedicated high-voltage capacitor, charging circuit, and switching device. A control module may be configured to activate the emitters individually, simultaneously, or in interleaved sequences according to a selected treatment mode.

[0192] An alternative configuration is illustrated in FIG. 30B, in which all or a portion of the flex tip 3002 itself serves as an electrode of the emitter pair 3004. A first hole is formed through the flex-tip wall, and a first conductor disposed in the hole forms a first electrode. A conductive portion of the flex-tip wall acts as a counter-electrode. A second hole and conductor may define a second emitter spaced axially or circumferentially from the first. Conductors extend through an internal lumen or along an inner member to the proximal IVL control system.

[0193] While the embodiments of FIGS. 30A and 30B illustrate closed-balloon configurations, open-balloon embodiments are shown in FIGS. 30C and 30D. In these embodiments, the balloon may include one or more fluid inlet and outlet openings that allow continuous supply and evacuation of liquid during operation to remove gas bubbles generated by emitter discharges. The balloon or flow shroud may be secured to the catheter assembly by adhesive bonding or thermal welding at proximal and distal attachment regions.

[0194] Figures 30E and 30F illustrate embodiments of an intravascular lithotripsy (IVL) catheter 3000 incorporating a guidewire 103 extending through a flex tip 3002 that supports both radial and axial lithotripsy emitters. The guidewire provides a central lumen along which the catheter may be advanced to a target lesion within a vessel. The distal region of the catheter includes the flex tip 3002, which is configured to bend or steer to facilitate accurate positioning of the emitters relative to a calcified lesion. A radial emitter pair 3004 is disposed along or within the wall of the flex tip to emit acoustic energy radially toward surrounding calcified tissue, while a distal axial-firing emitter 3008 is located near the distal end of the tip to generate forward-directed acoustic shockwaves along the guidewire path. As shown in Figure 30E, the balloon 104 may be a closed-balloon configuration configured to contain a dielectric or conductive fluid that supports spark42 Docket No.: 23812.31.2Ageneration and acoustic wave propagation. In this embodiment, while a single emitter is visible, the distal emitter 3008 may be implemented as part of an emitter pair with a corresponding emitter on an opposing side of the flex tip 3002. Note that electrical isolation may be needed between certain segments of the flex tip 3002.

[0195] In contrast, Figure 30F illustrates an open-balloon embodiment, in which the balloon defines an open flow path that allows continuous exchange of fluid across the emitters during operation to remove gas bubbles produced by discharge events and to maintain consistent acoustic coupling. In both embodiments, the guidewire lumen provides trackability and alignment during advancement, while the combined radial and axial emitters permit both forward and circumferential lithotripsy energy delivery to efficiently cross and remodel calcified occlusions.

[0196] While certain examples are shown here, it should be appreciated that other emitter configurations, such as those previously disclosed, could be used with the guidewire configurations illustrated.

[0197] FIG. 31 is a block diagram of an example computing device that may perform one or more of the operations described herein, in accordance with some embodiments. More particularly, computing device 3100 may be integrated in the IVL system 200, e.g., within the IVL control system 204 or the control handle 206, to perform any of the described operations. Computing device 3100 may be connected to other computing devices in a LAN, an intranet, an extranet, and / or the Internet. The computing device may operate in the capacity of a server machine in a client-server network environment or in the capacity of a client in a peer-to-peer network environment. The computing device may be provided by a personal computer (PC), a set-top box (STB), a server, a network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while only a single computing device is illustrated, the term “computing device” shall also be taken to include any collection of computing devices that individually or jointly execute a set (or multiple sets) of instructions to perform the methods discussed herein.

[0198] The example computing device 3100 may include one or more processing devices (e.g., a processor, a general purpose processing device, a PLD, etc.) 3102, a main memory 3104 (e.g., synchronous dynamic random access memory (DRAM), read-only memory (ROM)), a static memory 3105 (e.g., flash memory and a data storage device 3118), which may communicate with each other via a bus 3130.

[0199] The one or more processing devices 3102 may be provided by one or more general-43 Docket No.: 23812.31.2Apurpose processing devices such as a microprocessor, central processing unit, or the like. In an illustrative example, processing device(s) 3102 may comprise a complex instruction set computing (CISC) microprocessor, reduced instruction set computing (RISC) microprocessor, very long instruction word (VLIW) microprocessor, or a processing device implementing other instruction sets or processing devices implementing a combination of instruction sets. Processing device(s) 3102 may also comprise one or more special-purpose processing devices such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), network processor, or the like. The processing device(s) 3102 may be configured to execute the operations described herein, in accordance with one or more aspects of the present disclosure, for performing the operations and steps discussed herein.

[0200] Computing device 3100 may further include a network interface device 3108 which may communicate with a network 105. The computing device 3100 also may include a video display unit 3110 (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)), an alphanumeric input device 3112 (e.g., a keyboard), a cursor control device 3114 (e.g., a mouse) and an acoustic signal generation device 3115 (e.g., a speaker). In one embodiment, video display unit 3110, alphanumeric input device 3112, and cursor control device 3114 may be combined into a single component or device (e.g., an LCD touch screen to display GUI 2900).

[0201] Data storage device 3118 may include a computer-readable storage medium 3128 on which may be stored one or more sets of instructions 3125 that may include instructions for carrying out the operations described herein, in accordance with one or more aspects of the present disclosure. Instructions 3125 may also reside, completely or at least partially, within main memory 3104 and / or within processing device(s) 3102 during execution thereof by computing device 3100, main memory 3104 and processing device(s) 3102 also constituting computer-readable media. The instructions 3125 may further be transmitted or received over a network 3120 via network interface device 3108.

[0202] While computer-readable storage medium 3128 is shown in an illustrative example to be a single medium, the term “computer-readable storage medium” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database and / or associated caches and servers) that store the one or more sets of instructions. The term “computer-readable storage medium” shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by the machine and that cause the machine to perform the methods described herein, such as44 Docket No.: 23812.31.2Aactivating the emitter(s) of the IVL system 200. The term “computer-readable storage medium” shall accordingly be taken to include, but not be limited to, solid-state memories, optical media and magnetic media.

[0203] The following illustrates a number of various embodiments.

[0204] Clause 1. An intravascular lithotripsy (IVL) catheter for treating an occlusion in a vessel, comprising: a catheter shaft having a longitudinal axis; a balloon having an interior and an exterior, the balloon being capable of being inflated and deflated with a fluid; one or more emitters within the interior of the balloon, wherein the one or more emitters are capable of emitting an acoustic wave within the balloon when the balloon is inflated; and an axial-firing emitter located distal to the interior to emit acoustic waves in an axial direction along the longitudinal axis.

[0205] Clause 2. The IVL catheter of clause 1, wherein the axial -firing emitter includes one or more electrodes to generate an electrical spark or an optical fiber to deliver an optical beam to emit the acoustic waves in the exterior of the balloon, and wherein energy carried by the acoustic waves remains substantially in the exterior of the balloon without traveling into the interior of the balloon.

[0206] Clause 3. The IVL catheter of clause 2, wherein the axial-firing emitter includes a plurality of electrodes arranged concentrically about the longitudinal axis.

[0207] Clause 4. The IVL catheter of clause 3, wherein the plurality of electrodes includes a first electrode radially inward from a second electrode, and wherein a first distal edge of the first electrode is proximal to a second distal edge of the second electrode.

[0208] Clause 5. The IVL catheter of any one of clauses 1 to 4, further comprising: a catheter tip at a distal end of the catheter shaft, wherein the axial-firing emitter is located in the catheter tip.

[0209] Clause 6. The IVL catheter of clause 5, wherein the catheter tip includes: a tip interior distal to the axial-firing emitter; and the tip interior is in fluid communication with a fluid supply lumen.

[0210] Clause 7. The IVL catheter of clause 5 or 6, wherein the catheter tip comprises: a flex tip comprising a slotted tubular segment configured to flex in one or more directions when subjected to bending forces.

[0211] Clause 8. The IVL catheter of any one of clauses 5 to 7, wherein: a fluid supply lumen includes a guidewire lumen of the catheter shaft.

[0212] Clause 9. The IVL catheter of any one of clauses 5 to 7, wherein: the tip interior is in fluid communication with the interior of the balloon.45 Docket No.: 23812.31.2A

[0213] Clause 10. The IVL catheter of any one of clauses 5 to 9, wherein: the catheter tip includes an end cap distal to the axial-firing emitter; and the end cap is substantially acoustically transparent.

[0214] Clause 11. The IVL catheter of clause 10, wherein: the catheter tip includes a refractive focusing element to direct the acoustic waves through the end cap in a substantially axial direction.

[0215] Clause 12. The IVL catheter of clause 10, wherein: the catheter tip includes a reflective focusing element to direct the acoustic waves in a substantially axial direction through the end cap.

[0216] Clause 13. The IVL catheter of any one of clauses 1 to 12, wherein: the one or more emitters within the interior of the balloon are mounted on an inner member of the catheter shaft; and the acoustic wave is unfocused and at least in a substantially radial direction relative to the longitudinal axis of the catheter.

[0217] Clause 14. The IVL catheter of clause 13, wherein: the balloon includes a balloon wall circumferentially surrounding the one or more emitters; the balloon wall has a first wall section circumferentially offset from a second wall section when inflated; and the first wall section is more transmissive of the acoustic waves than the second wall section.

[0218] Clause 15. The IVL catheter of clause 14, wherein: the first wall section and the second wall section each include a base layer; and the second wall section further includes an acoustically reflective layer disposed on the base layer.

[0219] Clause 16. The IVL catheter of clause 14 or 15, wherein: the first wall section has a different density than the second wall section.

[0220] Clause 17. The IVL catheter of any one of clauses 14 to 16, wherein: the first wall section has a different thickness than the second wall section.

[0221] Clause 18. The IVL catheter of any one of clauses 13 to 17, wherein: the balloon includes one or more balloon septa dividing a balloon volume into a plurality of balloon chambers.

[0222] Clause 19. The IVL catheter of any one of clauses 13 to 18, wherein: the balloon includes a balloon wall circumferentially surrounding the one or more radial-firing emitters; and a wall profile of the balloon wall is elliptical.

[0223] Clause 20. An intravascular lithotripsy (IVL) system, comprising: an IVL control system including a pulse generator; and an IVL catheter according to any one of clauses 1 to 19, wherein the IVL catheter includes a control handle coupled to the pulse generator, and wherein the axial-firing emitter is configured to emit, based on a signal received from46 Docket No.: 23812.31.2Athe pulse generator through the control handle, acoustic waves with a substantial component traveling in a distal, axial direction along the longitudinal axis.

[0224] Clause 21. The IVL system of clause 20, wherein: the axial-firing emitter emits the acoustic waves in the exterior of the balloon; and energy carried by the acoustic waves remains substantially in the exterior of the balloon without traveling into the interior of the balloon.

[0225] Clause 22. The IVL system of clause 20 or 21, wherein: the IVL control system includes a fluid supply subsystem fluidically coupled to a fluid connector of the IVL catheter.

[0226] Clause 23. A method of treating a calcified lesion in a body lumen, comprising: delivering an IVL catheter according to any one of clauses 1 to 19 over a guidewire to a calcified lesion; activating an axial-firing emitter to emit acoustic waves having a substantial component traveling in a distal, axial direction along the longitudinal axis into the calcified lesion while the balloon is deflated; and advancing the IVL catheter through the calcified lesion while the balloon is deflated.

[0227] Clause 24. The method of clause 23, wherein: the axial-firing emitter emits the acoustic waves in the exterior of the balloon; and energy carried by the acoustic waves remains substantially in the exterior of the balloon without traveling into the interior of the balloon.

[0228] Clause 25. The method of clause 23 or 24, further comprising: retracting the guidewire proximal to the axial-firing emitter before activating the axial-firing emitter.

[0229] Clause 26. The method of any one of clauses 23 to 25, wherein: the IVL catheter includes one or more radial-firing emitters mounted on an inner member of the catheter shaft within the interior of the balloon; and further comprising activating the one or more radial-firing emitters to emit acoustic waves in a radial direction into the calcified lesion.

[0230] Clause 27. The method of clause 26, wherein: the acoustic waves emitted in the radial direction are substantially unfocused.

[0231] Clause 28. The method of any one of clauses 23 to 27, wherein: the balloon includes a plurality of balloon chambers; and further comprising filling the plurality of balloon chambers with respective fluids having different densities.

[0232] Clause 29. The IVL catheter of any one of clauses 1 to 19, further comprising: an inner member of the catheter shaft disposed at least partially within the balloon; and one or more wires embedded in the inner member coupled to the one or more emitters and configured to transmit signals to the one or more emitters.47 Docket No.: 23812.31.2A

[0233] Clause 30. The IVL catheter of clause 29, wherein: the one or more emitters comprise a partial cylindrical electrode member.

[0234] Clause 31. The IVL catheter of clause 30, wherein: the partial cylindrical electrode member has a diameter similar to a diameter of the inner member.

[0235] Clause 32. The IVL catheter of clause 30 or 31, wherein: the partial cylindrical electrode member includes a groove configured to pass a wire embedded in a first portion of the inner member to a second portion of the inner member.

[0236] Clause 33. The IVL catheter of any one of clauses 30 to 32, wherein: the partial cylindrical electrode member comprises a metal-embedded polymer.

[0237] Clause 34. The IVL catheter of any one of clauses 30 to 33, wherein: the partial cylindrical electrode member comprises a radiopaque agent.

[0238] Clause 35. The IVL catheter of clause 29, wherein: the one or more wires are coextruded into the inner member.

[0239] Clause 36. The IVL catheter of clause 29 or 35, wherein: the one or more wires are formed by filling a groove of the inner member with conductive material and overlaying an insulating material.

[0240] Clause 37. The IVL catheter of clause 29, wherein: the one or more wires are included in a ribbon cable.

[0241] Clause 38. The IVL catheter of clause 29, wherein: the one or more wires embedded in the inner member comprise two wires forming an emitter at a distal end of the IVL catheter configured to cause an axial pressure pulse.

[0242] Clause 39. The IVL catheter of clause 38, wherein: a fluid supply lumen, a fluid return lumen, and a guidewire lumen are coextruded into the inner member.

[0243] Clause 40. The IVL catheter of clause 38 or 39, wherein: a fluid supply lumen, a fluid return lumen, and a guidewire lumen are assembled into the inner member.

[0244] In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.48 Docket No.: 23812.31.2A

Claims

1. CLAIMSWhat is claimed is:

1. An intravascular lithotripsy (IVL) catheter for treating an occlusion in a vessel, comprising: a catheter shaft having a longitudinal axis; a balloon having an interior and an exterior, the balloon being capable of being inflated and deflated with a fluid; one or more emitters within the interior of the balloon, wherein the one or more emitters are capable of emitting an acoustic wave within the balloon when the balloon is inflated; and an axial-firing emitter located distal to the interior to emit acoustic waves in an axial direction along the longitudinal axis.

2. The IVL catheter of claim 1, wherein the axial -firing emitter includes one or more electrodes to generate an electrical spark or an optical fiber to deliver an optical beam to emit the acoustic waves in the exterior of the balloon, and wherein energy carried by the acoustic waves remains substantially in the exterior of the balloon without traveling into the interior of the balloon.

3. The IVL catheter of claim 2, wherein the axial-firing emitter includes a plurality of electrodes arranged concentrically about the longitudinal axis.

4. The IVL catheter of claim 3, wherein the plurality of electrodes includes a first electrode radially inward from a second electrode, and wherein a first distal edge of the first electrode is proximal to a second distal edge of the second electrode.

5. The IVL catheter of any one of claims 1 to 4, further comprising: a catheter tip at a distal end of the catheter shaft, wherein the axial-firing emitter is located in the catheter tip.

6. The IVL catheter of claim 5, wherein the catheter tip includes: a tip interior distal to the axial-firing emitter; and the tip interior is in fluid communication with a fluid supply lumen.

7. The IVL catheter of claim 5 or 6, wherein the catheter tip comprises: a flex tip comprising a slotted tubular segment configured to flex in one or more directions when subjected to bending forces.

8. The IVL catheter of any one of claims 5 to 7, wherein: a fluid supply lumen includes a guidewire lumen of the catheter shaft.49 Docket No.: 23812.31.2A9. The IVL catheter of any one of claims 5 to 7, wherein: the tip interior is in fluid communication with the interior of the balloon.

10. The IVL catheter of any one of claims 5 to 9, wherein: the catheter tip includes an end cap distal to the axial-firing emitter; and the end cap is substantially acoustically transparent.

11. The IVL catheter of claim 10, wherein: the catheter tip includes a refractive focusing element to direct the acoustic waves through the end cap in a substantially axial direction.

12. The IVL catheter of claim 10, wherein: the catheter tip includes a reflective focusing element to direct the acoustic waves in a substantially axial direction through the end cap.

13. The IVL catheter of any one of claims 1 to 12, wherein: the one or more emitters within the interior of the balloon are mounted on an inner member of the catheter shaft; and the acoustic wave is unfocused and at least in a substantially radial direction relative to the longitudinal axis of the catheter.

14. The IVL catheter of claim 13, wherein: the balloon includes a balloon wall circumferentially surrounding the one or more emitters; the balloon wall has a first wall section circumferentially offset from a second wall section when inflated; and the first wall section is more transmissive of the acoustic waves than the second wall section.

15. The IVL catheter of claim 14, wherein: the first wall section and the second wall section each include a base layer; and the second wall section further includes an acoustically reflective layer disposed on the base layer.

16. The IVL catheter of claim 14 or 15, wherein: the first wall section has a different density than the second wall section.

17. The IVL catheter of any one of claims 14 to 16, wherein: the first wall section has a different thickness than the second wall section.

18. The IVL catheter of any one of claims 13 to 17, wherein: the balloon includes one or more balloon septa dividing a balloon volume into a50 Docket No.: 23812.31.2Aplurality of balloon chambers.

19. The IVL catheter of any one of claims 13 to 18, wherein: the balloon includes a balloon wall circumferentially surrounding the one or more radial-firing emitters; and a wall profile of the balloon wall is elliptical.

20. An intravascular lithotripsy (IVL) system, comprising: an IVL control system including a pulse generator; and an IVL catheter according to any one of claims 1 to 19, wherein the IVL catheter includes a control handle coupled to the pulse generator, and wherein the axial-firing emitter is configured to emit, based on a signal received from the pulse generator through the control handle, acoustic waves with a substantial component traveling in a distal, axial direction along the longitudinal axis.

21. The IVL system of claim 20, wherein: the axial-firing emitter emits the acoustic waves in the exterior of the balloon; and energy carried by the acoustic waves remains substantially in the exterior of the balloon without traveling into the interior of the balloon.

22. The IVL system of claim 20 or 21, wherein: the IVL control system includes a fluid supply subsystem fluidically coupled to a fluid connector of the IVL catheter.

23. A method of treating a calcified lesion in a body lumen, comprising: delivering an IVL catheter according to any one of claims 1 to 19 over a guidewire to a calcified lesion; activating an axial-firing emitter to emit acoustic waves having a substantial component traveling in a distal, axial direction along the longitudinal axis into the calcified lesion while the balloon is deflated; and advancing the IVL catheter through the calcified lesion while the balloon is deflated.

24. The method of claim 23, wherein: the axial-firing emitter emits the acoustic waves in the exterior of the balloon; and energy carried by the acoustic waves remains substantially in the exterior of the balloon without traveling into the interior of the balloon.

25. The method of claim 23 or 24, further comprising: retracting the guidewire proximal to the axial-firing emitter before activating the axial-firing emitter.51 Docket No.: 23812.31.2A26. The method of any one of claims 23 to 25, wherein: the IVL catheter includes one or more radial-firing emitters mounted on an inner member of the catheter shaft within the interior of the balloon; and further comprising activating the one or more radial-firing emitters to emit acoustic waves in a radial direction into the calcified lesion.

27. The method of claim 26, wherein: the acoustic waves emitted in the radial direction are substantially unfocused.

28. The method of any one of claims 23 to 27, wherein: the balloon includes a plurality of balloon chambers; and further comprising filling the plurality of balloon chambers with respective fluids having different densities.

29. The IVL catheter of any one of claims 1 to 19, further comprising: an inner member of the catheter shaft disposed at least partially within the balloon; and one or more wires embedded in the inner member coupled to the one or more emitters and configured to transmit signals to the one or more emitters.

30. The IVL catheter of claim 29, wherein: the one or more emitters comprise a partial cylindrical electrode member.

31. The IVL catheter of claim 30, wherein: the partial cylindrical electrode member has a diameter similar to a diameter of the inner member.

32. The IVL catheter of claim 30 or 31, wherein: the partial cylindrical electrode member includes a groove configured to pass a wire embedded in a first portion of the inner member to a second portion of the inner member.

33. The IVL catheter of any one of claims 30 to 32, wherein: the partial cylindrical electrode member comprises a metal-embedded polymer.

34. The IVL catheter of any one of claims 30 to 33, wherein: the partial cylindrical electrode member comprises a radiopaque agent.

35. The IVL catheter of claim 29, wherein: the one or more wires are coextruded into the inner member.

36. The IVL catheter of claim 29 or 35, wherein: the one or more wires are formed by filling a groove of the inner member52 Docket No.: 23812.31.2Awith conductive material and overlaying an insulating material.

37. The IVL catheter of claim 29, wherein: the one or more wires are included in a ribbon cable.

38. The IVL catheter of claim 29, wherein: the one or more wires embedded in the inner member comprise two wires forming an emitter at a distal end of the IVL catheter configured to cause an axial pressure pulse.

39. The IVL catheter of claim 38, wherein: a fluid supply lumen, a fluid return lumen, and a guidewire lumen are coextruded into the inner member.

40. The IVL catheter of claim 38 or 39, wherein: a fluid supply lumen, a fluid return lumen, and a guidewire lumen are assembled into the inner member.53 Docket No.: 23812.31.2A

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