Intravascular lithotripsy catheter having balloon features

Abstract

Embodiments are disclosed of an intravascular lithotripsy (IVL) catheter. The IVL catheter includes a catheter shaft having a proximal end and a distal end. A balloon is positioned at or near the distal end of the catheter shaft. The balloon has a distal end and a proximal end and includes a distal shoulder at the distal end of the balloon and a proximal shoulder at the proximal end of the balloon. The distal shoulder has a lower shoulder angle than the proximal shoulder. A plurality of spaced-apart emitters are positioned inside the balloon.

Description

INTRAVASCULAR LITHOTRIPSY CATHETER HAVING BALLOON FEATURESCROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of U.S. Patent Application No.63 / 738,333, filed December 23, 2024, and entitled INTRAVASCULAR LITHOTRIPSY CATHETER HAVING BALLOON FEATURES, the entire content of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The disclosed embodiments relate to lithotripsy systems for treating calcifications. More specifically, the disclosed embodiments relate to intravascular lithotripsy catheters useful for disturbing calcified lesions of body vessels.BACKGROUND

[0003] Cardiovascular diseases are a leading cause of morbidity and mortality worldwide. A significant number of these conditions involve the formation of calcified lesions within 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.

[0004] Traditional methods for addressing calcified lesions include balloon angioplasty, which involves inflation of a balloon within the vessel to compress the plaque, and atherectomy, which involves mechanically removing the plaque. 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. And atherectomy, while effective in removing plaque, carries risks such as embolization and damage to the vessel wall.

[0005] An emerging technique for treating calcified lesions is intravascular lithotripsy (IVL). IVL uses acoustic pressure waves to fracture a calcified plaque. The fractured plaque can become more pliable and easier to open with subsequent balloon angioplasty. Accordingly, the method has the potential to improve the safety and efficacy of percutaneous coronary interventions (PCI) in patients with heavily calcified lesions. SUMMARY

[0006] In one example embodiment, an intravascular lithotripsy (IVL) catheter including: a catheter shaft having a proximal end and a distal end; a balloon positioned at or near the distal end of the catheter shaft, the balloon having a distal end and a proximal end, whereinDocket No. 23812.52a 1the balloon includes a distal shoulder at the distal end of the balloon and a proximal shoulder at the proximal end of the balloon, the distal shoulder and the catheter shaft forming a shoulder angle that opens proximally and is lower than a shoulder angle formed between the proximal shoulder and the catheter shaft and that opens distally; and a plurality of spaced-apart emitters positioned inside the balloon.

[0007] In one example embodiment, an intravascular lithotripsy (IVL) catheter including: a catheter shaft having a proximal end and a distal end; a balloon positioned at or near the distal end of the catheter shaft, the balloon having a distal end and a proximal end, wherein the balloon includes a plurality of chambers; and a plurality of spaced-apart emitters positioned inside the balloon with each chamber of the balloon substantially surrounding at least a corresponding one of the plurality of emitters.

[0008] In one example embodiment, an intravascular lithotripsy (IVL) catheter including: a catheter shaft having a proximal end and a distal end; a balloon positioned at or near the distal end of the catheter shaft, wherein, when deflated, the balloon is circumferentially wrapped around the catheter shaft so that a cross-sectional profile at any longitudinal location along the balloon is eccentric or non-axisymmetric relative to a central axis of the catheter shaft, such that the balloon extends laterally further to one side of the catheter shaft than another at any longitudinal location along the balloon; and a plurality of spaced-apart emitters positioned inside the balloon.

[0009] In one example embodiment, an intravascular lithotripsy (IVL) catheter including: a catheter shaft having a proximal end and a distal end, the catheter shaft including an outer member and an inner member, the inner member defining a guidewire lumen; and a balloon mounted at or near the distal end of the catheter shaft, the balloon including: a proximal end attached to the distal end of the outer member; a distal end attached to the inner member; and a plurality of chambers and passageways formed in the balloon and helically arranged around the inner member.

[0010] In one example embodiment, an intravascular lithotripsy (IVL) catheter including: a catheter shaft having a proximal end and a distal end, the catheter shaft including an outer member and an inner member, the inner member defining a guidewire lumen; and a balloon positioned at or near the distal end of the catheter shaft, the balloon having a proximal end attached to the outer member and a plurality of eccentric lobes formed in the balloon, each eccentric lobe extending circumferentially around only a portion of the inner member.Docket No. 23812.52a 2

[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] Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0013] Fig. 1 is a diagrammatic cross section of an embodiment of a vessel illustrating an example activation of an intravascular lithotripsy catheter adjacent to a calcified lesion.

[0014] Fig. 2 is a perspective view of an embodiment of an intravascular lithotripsy system.

[0015] Fig. 3 is a side view of an embodiment of an over-the-wire intravascular lithotripsy catheter.

[0016] Fig. 4 is a side view of an embodiment of a rapid exchange intravascular lithotripsy catheter.

[0017] Fig. 5 is a side view of an embodiment of a control handle of an intravascular lithotripsy catheter.

[0018] Fig. 6 is a cutaway perspective view of an embodiment of a distal portion of an intravascular lithotripsy catheter.

[0019] Fig. 7 is a sectional view of an embodiment of a catheter shaft of an intravascular lithotripsy catheter.

[0020] Figs. 8A-8B are side views of an embodiment of a distal portion of an IVL catheter.

[0021] Fig. 9 is a side view of another embodiment of a distal portion of an IVL catheter.

[0022] Fig. 10 is a side view of another embodiment of a distal portion of an IVL catheter.

[0023] Fig. 11 is a side view of another embodiment of a distal portion of an IVL catheter.

[0024] Figs. 12A-12D are side views of embodiments of balloons with features for compact folding.

[0025] Fig. 12E shows multiple longitudinally-looking views of various embodiments of balloon pleating.

[0026] Figs. 13 A and 13B perspective and cross-sectional views of another embodiment of a distal portion of an IVL catheter.Docket No. 23812.52a 3

[0027] Figs. 14A and 14B perspective and cross-sectional views of another embodiment of a distal portion of an IVL catheter.

[0028] Fig. 15 is a flowchart of another embodiment of a method for using an IVL catheter.

[0029] Fig. 16 is a flowchart of another embodiment of a method for using an IVL catheter.DETAILED DESCRIPTION

[0030] Embodiments are described of IVL catheters for modification of lesions (i.e., blockages or occlusions) in a blood vessel. Specific details are described to provide an understanding of the embodiments, but one skilled in the relevant art will recognize that the invention can be practiced without one or more of the described details or with other methods, components, materials, etc. In some instances, well-known structures, materials, or operations are not shown or described in detail but are nonetheless encompassed within the scope of the invention.

[0031] Reference throughout this specification to “one embodiment” or “an embodiment” means that a described feature, structure, or characteristic can be included in at least one described embodiment, so that appearances of “in one embodiment” or “in an embodiment” do not necessarily all refer to the same embodiment. Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0032] As used in this application, directional terms such as “left,” “right,” “front,” “rear,” “upper,” lower,” “top,” “bottom,” “side,” “lateral,” “longitudinal,” etc., refer to the orientations of embodiments as they are presented in the drawings, but any directional term should not be interpreted to imply or require a particular orientation of the described embodiments when in actual use. The use of relative terms throughout the description can denote a relative position or direction. For example, “distal” can indicate a first direction along a longitudinal axis of a biostimulator transport system and “proximal” can indicate a second direction opposite to the first direction. Such terms are provided to establish relative frames of reference, but are not intended to limit the use or orientation of the disclosed devices to a specific configuration described in the various embodiments below.

[0033] Lithotripsy is a procedure that uses acoustic energy (e.g., pressure waves, shock waves, or ultrasonic energy) to break up calcifications such as kidney stones in a urinary system. Intravascular lithotripsy (IVL) is a related procedure that similarly uses acoustic energy to disrupt or modify a calcified lesion at a vessel location in a vascular system. An IVL catheter can include lithotripsy emitters to generate the acoustic energy, and a balloon that can be expanded into the disrupted lesion to prepare the vessel location for furtherDocket No. 23812.52a 4procedures such as stenting. The balloons can be required to cross tight lesions, or conform to irregularly shaped calcifications, but existing IVL catheters use balloon designs that are not uniquely suited to these challenging anatomies. For instance, current balloon designs can have poor “crossability,” which is a measure of the balloon’s ability to cross (i.e., penetrate and go through) a lesion so that the lesion can then be disrupted or modified. Accordingly, IVL may be difficult to perform, or to perform successfully, using existing platforms. Embodiments are described below of IVL catheters with balloon features that can promote device delivery, or enhance device function, within the context of IVL.

[0034] Fig. 1 illustrates a diagrammatic cross section of a vessel illustrating an embodiment of activation of an intravascular lithotripsy catheter adjacent to a calcified lesion. An intravascular lithotripsy (IVL) catheter 100 can be introduced into a bodily vessel, such as a blood vessel, of a patient over a guidewire 103. The IVL catheter includes a balloon 104 mounted on a catheter shaft 106. The blood vessel, which serves as the target anatomy, contains a lesion 108 within a vessel wall 110. More particularly, the lesion can include a calcified lesion restricting the flow of a medium, such as blood, through the vessel.

[0035] As the IVL catheter is advanced through vessel 102, the balloon 104 is positioned adjacent to the calcified lesion 108. Once in place, the balloon can be expanded against the vessel wall 110. One or more emitters (Fig. 6) can be contained within the balloon. The emitters are elements used to generate short pressure pulses or pressure waves (i.e., acoustic energy) that propagate outward toward the lesion. Examples of emitters that can be used in different embodiments 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. Each emitter produces a pressure wave 114 that propagates outward toward the lesion.

[0036] The pressure waves 114 generated by the emitters can cause one or more cracks 116 to form in the calcified lesion. These cracks disrupt the lesion, making it more pliable and easier to treat with subsequent interventions like balloon angioplasty. The illustration demonstrates the mechanism by which the IVL catheter effectively targets and disrupts calcified lesions within the blood vessel, thereby improving the safety and efficacy of percutaneous coronary interventions (PCI) in patients with heavily calcified lesions.

[0037] Fig. 2 illustrates a perspective view of an embodiment of an intravascular lithotripsy system 200. An IVL system includes an IVL catheter 100 designed to disrupt calcified lesions within a blood vessel, as described above. The IVL catheter comprisesDocket No. 23812.52a 5the balloon 104 mounted on the catheter shaft, which can be positioned adjacent to and expanded against a calcified lesion to facilitate the treatment of the lesion.

[0038] The IVL system also includes a fluid pump 202 that is fluidically coupled to the balloon. The fluid pump can be used to inflate and deflate the balloon as needed during the procedure. For example, the fluid pump can convey a saline solution or mixture to the balloon to expand the balloon against the vessel wall. By controlling the fluid pressure within the balloon, the fluid pump ensures that the balloon can be precisely positioned and expanded to effectively target the calcified lesion. This controlled inflation and deflation facilitate accurate delivery of lithotripsy energy to the lesion.

[0039] The IVL catheter may be electrically connected to an IVL control system 204 via a control handle 206. The IVL control system can include an electric pulse generator that generates the electrical signals required to activate the emitters within the balloon. For example, the IVL control system 204 can include a memory that stores system settings and / or other instructions which, when executed by a processing device of the IVL system, cause the IVL system to transmit the electrical signals to control handle 206. These electrical signals are transmitted through the control handle to the emitters, which then generate an electrical arc. The electrical arc produces the pressure wave that propagates outward toward the calcified lesion. Accordingly, the IVL control system can provide the electrical energy to power the lithotripsy procedure.

[0040] The control handle 206 serves as a user interface for the IVL system. The control handle can allow the user to manage the operation of the IVL catheter, including the activation of the emitters. Optionally, the control handle can control inflation and deflation of the balloon when a fluid delivery system is integral to the IVL control system (not shown). The control handle typically features buttons or other input mechanisms that the user can press to generate the electrical arc and produce the pressure wave. The control handle interface ensures that the clinician can easily and effectively control the IVL system during the procedure.

[0041] Fig. 3 illustrates a side view of an embodiment of an over-the-wire intravascular lithotripsy catheter 100. The IVL catheter can have an over-the-wire (OTW) guidewire configuration. In the OTW configuration, the guidewire 103 can enter the IVL catheter 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 within the vessel. Guidewire 103 provides a stable pathway for the catheter, enabling the clinician to accurately target the calcified lesion. Once the catheter is in position, the balloon can beDocket No. 23812.52a 6expanded, and the emitters can be activated to generate the pressure waves that disrupt the lesion.

[0042] The IVL catheter includes the balloon 104 mounted on the catheter shaft 106, as described below. The catheter shaft can provide structural support and serves as a conduit for the guidewire, fluid, and electrical connections necessary for operation of the IVL system. For example, the catheter shaft can connect to the hub 302, which conveys fluid and electrical signals between a distal portion of the IVL catheter and external components. The hub can pass electrical signals between the control handle and the emitters within the balloon to produce the pressure wave, as described above. For example, the electrical signals can travel along wires in an electrical cable 304 of the control handle, which connects to the hub. The wires can extend through the hub and into the catheter shaft, and extend distally to the emitters in the balloon.

[0043] In addition to the electrical connection, hub 302 can also include a fluid connector 306 to pass fluid from the fluid pump to the balloon. This fluid connector can convey fluid between the fluid pump and an inflation lumen in the catheter shaft (see Fig. 7), through the hub. The inflation fluid can travel along the catheter shaft into the balloon to inflate and deflate the balloon during a procedure.

[0044] Fig. 4 illustrates a side view of an embodiment of a rapid exchange IVL catheter 100. The IVL catheter can have a rapid exchange (RX) guidewire configuration. As in the OTW guidewire configuration, the RX version of the IVL catheter can include the catheter shaft 106, the balloon 104, and the hub 302. The hub configuration and guidewire routing of the RX configuration may, however, differ from the OTW configuration.

[0045] In an embodiment, a hub 302 is located at a proximal end of the catheter shaft 106. The hub can include the electrical connector, to allow for the transmission of electrical signals from the IVL control system to the emitters within the balloon, and the fluid connector, to enable the passage of the inflation fluid from the fluid pump to the balloon. The hub may not, however, have an exit port for guidewire 103. The exit port may be an RX port 402 positioned distal to the hub along the catheter shaft.

[0046] The RX port 402 can be positioned between the distal tip and the hub of the IVL catheter. The RX port can include a hole in an outer surface of the catheter shaft that allows the guidewire 103 to transition from a location external to the catheter shaft to a location internal to the catheter shaft, e.g., supporting the balloon. In an embodiment, the guidewire can enter the IVL catheter through the distal catheter tip and exit through the RX port. The RX configuration allows for quick and efficient exchange of the guidewire, facilitatingDocket No. 23812.52a 7precise navigation and positioning of the IVL catheter within the vessel. The RX port 402 provides a stable pathway for the catheter, enabling the clinician to accurately target the calcified lesion.

[0047] Fig. 5 illustrates a side view of an embodiment of a control handle 206 of an intravascular lithotripsy catheter. The control handle of the IVL catheter includes the electrical cable 304, a grip 502, an electrical connector 504, and a control element 506. The control handle serves as a user interface for the IVL system. More particularly, the grip 502 provides a surface for a user to hold and manipulate the control handle during the procedure. The grip can be ergonomically designed to ensure comfort and ease of use for the user.

[0048] The electrical cable 304 can connect the control handle 206 to the hub of the intravascular lithotripsy catheter. The electrical cable transmits electrical signals from the IVL control system to the emitters within the balloon of the catheter. The electrical connector 504 can be positioned at the proximal end of the control handle. The electrical connector can connect to the IVL control system. The electrical connector can receive the electrical signals generated by the IVL control system, which then transmit through the electrical cable to the hub and subsequently to the emitters within the balloon.

[0049] The control element 506 can be integrated into the grip of the control handle 206. The control element can include one or more buttons, switches, or other input mechanisms. The user can press the button to activate the emitters within the balloon. This activation generates the electrical arc, which produces the pressure waves necessary for the lithotripsy procedure. The control element allows the clinician to precisely control the timing and intensity of the electrical signals, ensuring effective treatment of the calcified lesions. The control handle 206, with the integrated grip 502, electrical cable 304, electrical connector 504, and control element 506, provides the interface for the clinician to manage 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.

[0050] Fig. 6 illustrates a cutaway perspective view of an embodiment of a distal portion of an intravascular lithotripsy catheter. A catheter tip 602 can be positioned at a distal end of the IVL catheter. As described above, the catheter tip facilitates navigation of the catheter over the guidewire through the blood vessel to the target lesion. The catheter tip can be designed to be atraumatic to minimize damage to the vessel walls during the procedure, ensuring safe and effective advancement of the catheter to the site of theDocket No. 23812.52a 8calcified lesion. More particularly, catheter tip 602 can receive and track over the guidewire to the target anatomy within the vessel.

[0051] The balloon 104 can be mounted on the catheter shaft 106 and may be positioned adjacent to the catheter tip. More particularly, a distal end of the balloon can be coupled, e.g., sealed, to the catheter tip 602 and a proximal end of the balloon can be coupled, e.g., sealed, to the catheter shaft 106. The balloon may therefore provide a hermetically sealed interior longitudinally between the catheter tip and the catheter shaft so that the balloon can be inflated and pressurized with fluid such as saline. The inflation fluid for the balloon can then serve as a medium for the transmission of pressure waves generated by an emitter within the interior of the balloon. More particularly, the emitter can generate the electrical spark that produces the pressure waves used to disrupt the calcified lesion.

[0052] The IVL catheter can include an inner member 606, which can be integral to the catheter shaft. More particularly, the catheter shaft can include the inner member located within an outer member 608. The outer member can support the proximal end of the balloon. The inner member can extend through the balloon to the distal tip 602 of the catheter. The inner member supports the emitters 604 and may also provide a pathway for the guidewire. The inner member can ensure the proper alignment and positioning of the emitters within the balloon, which facilitates the effective generation and transmission of pressure waves to the calcified lesion.

[0053] Emitters 604 can be contained within the balloon 104 and may be responsible for generating the electrical arc that produces the pressure wave. The emitters can include several emitter portions separated by a gap across which the spark is generated. When electrical signals from the IVL control system are transmitted to the emitter, the electrical spark forms across the gap between the emitter portions. For example, the balloon can be filled with saline or another electrolytic solution that supports formation of the electrical spark. The spark creates the electrical arc, which in turn produces the pressure wave that propagates outward through the inflation fluid and the balloon wall toward the calcified lesion.

[0054] Fig. 7 illustrates a sectional view of an embodiment of a catheter shaft 106 of an intravascular lithotripsy catheter. The catheter shaft 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. For example, the catheter shaft includes the outer member 608 and the inner member 606.Docket No. 23812.52a 9

[0055] The outer member 608 can be the outermost layer of the catheter shaft. The outer member provides structural support and protection for the internal components of the catheter. The outer member is designed to be biocompatible and flexible, allowing the catheter to navigate through the vascular system without causing damage to the vessel walls. The outer member can include a tubular wall extending along a longitudinal axis from the hub to the balloon.

[0056] The inner member 606 can be located within the outer member and can provide additional structural support. The inner member may include a tubular wall extending along the longitudinal axis, e.g., coaxial with the outer member. The inner member can house a guidewire lumen 702, through which the guidewire may pass. Accordingly, the inner member may extend from the hub to the catheter tip in the OTW version of the IVL catheter, or from the RX port to the catheter tip in the RX version of the IVL catheter. It will be appreciated that, in the RX version, a hypotube (not shown in cross-section, but proximal to the RX port in Fig. 4) can connect the hub to the distal portion of the IVL catheter. 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 into an inflation lumen that extends into the balloon.

[0057] The inflation lumen 704 can be an internal channel within the catheter shaft between the inner member 606 and the outer member 608. The inflation lumen can allow fluid to be delivered to the balloon. The inflation lumen 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. In any case, the inflation lumen permits the passage of the inflation fluid, e.g., a saline solution or mixture, into the balloon to support balloon inflation and spark generation.

[0058] In an embodiment, one or more wires 706 are positioned within the catheter shaft and used to transmit electrical signals from the control handle to the emitters within the balloon. For example, each emitter 604 can be connected to one or more wires 706 to electrify the emitter portions and generate the electrical arc. Each wire 706 may be insulated to prevent electrical interference with other components of the IVL catheter. Insulation of the wire(s) can also be provided by a wire sheath that surrounds the wires, providing additional insulation and protection. The wire sheath may, for example, be a tubular member or heat shrink that encases the wires between the wire sheath and the inner member. The wires may therefore be separated from inflation fluid within the inflation lumen. Accordingly, the wires may remain securely in place within the catheter shaft andDocket No. 23812.52a 10prevent any potential damage or electrical leakage during navigation of the IVL catheter through the vessel.

[0059] Figs. 8A-8B illustrate embodiments of the distal end of an IVL catheter having balloons with tapered shoulders. Fig. 8A illustrates the distal end of an IVL catheter 800. The catheter includes a catheter shaft having an outer member 802 with a distal end 804 and a proximal end (not shown in this drawing, but see, e.g., Figs. 3-4). The outer member has within it a lumen 806. An inner member 808 is positioned within lumen 806 and has a distal end 809 and a proximal end that is not shown in this drawing. In some embodiments, inner member 808 can include a guidewire lumen (not shown) to accommodate a guidewire.

[0060] One or more emitters 810 are positioned on inner member 808 between the distal end 809 of the inner member and where the inner member exits lumen 806. In the illustrated embodiment the emitters are positioned directly on the inner member, but in other embodiments there can be intervening elements between the emitters and the inner member, and in still other embodiments the emitters can be positioned somewhere other than the inner member. Emitters 810 receive electrical pulses from circuitry connected to and running within the catheter (see, e.g., Figs. 2 and 6-7) and convert the received electrical pulses into acoustic pulses (i.e., acoustic energy in the form of acoustic waves such as pressure waves or shock waves). The illustrated embodiment includes four emitters 810, but other embodiments can include more or less emitters than shown. And in the illustrated embodiment emitters 810 are uniformly spaced (i.e., inter-emitter distance d is constant), but in other embodiments they need not be uniformly spaced.

[0061] A balloon 812 is positioned at the distal end of the catheter. The proximal end 814 of balloon 812 is attached to distal end 804 of outer member 802, and a distal end 816 of the balloon is attached to inner member 808 at or near distal end 809. In different embodiments balloon 812 can have a longitudinal dimension L between 12 and 60mm, but in other embodiments the longitudinal dimension need not be in this range. In the illustrated configuration, balloon 812 substantially surrounds emitters 810 so that, when balloon 812 is inflated, acoustic energy from emitters 810 travels through the fluid that fills the balloon, and through the balloon itself, to the lesion being disrupted or modified.

[0062] Balloon 812 has three parts: a distal shoulder 818, an intermediate section 820, and a proximal shoulder 822. Distal shoulder 818 tapers distally, meaning that its radial dimension decreases in the distal direction so that the distal shoulder has a distal shoulder angle A relative to inner member 808. In one embodiment angle A can have a value equalDocket No. 23812.52a 11to or less than 45 degrees, but other embodiments need not be limited to this range. Proximal shoulder 822 tapers proximally, meaning that its radial dimension decreases in the proximal direction or, put differently, its radial dimension increases in the distal direction. The proximal shoulder has a proximal shoulder angle B relative to inner member 808. In embodiments of balloon 812, proximal shoulder angle B is greater than distal shoulder angle A — i.e., the distal shoulder is sharper or narrower than the proximal shoulder, or the proximal shoulder is blunter than the distal shoulder. Intermediate section 820 connects the distal and proximal shoulders. In the illustrated embodiment intermediate section 820 has a substantially constant radial dimension, but in other embodiments its radial dimension need not be constant. The tapered distal and proximal shoulders can help reduce distal crossing profile and maximize calcium contact, especially on the proximal end. Among other things, the tapered shoulders reduce the amount of material needed to form the balloon, thus creating less bulk that must cross a lesion.

[0063] In one embodiment balloon 812 can be a high-pressure non-compliant balloon formed of a harder (i.e., higher durometer) material such as nylon. The non-compliant balloon can be inflated against the lesion to put calcium under stress and shock waves (i.e., pressure waves or acoustic waves) can then be delivered by the emitters through the inflated balloon to disrupt or break up the lesion. In other embodiments the balloon can be formed of softer materials to allow it to conform to the lesion; in particular, the balloon material can be selected to allow the balloon to conform to irregularly-shaped lesions. In an embodiment, the balloon is formed from a low-durometer polyurethane balloon to increase compliance / contact, but other embodiments can use other materials. In still other embodiments, the balloon can be a multi-layer balloon with two or more layers of material. The balloon can also be enhanced to improve crossability by forming the balloon in a low profile. In one embodiment, for instance, the balloon can be heat-set to have a small diameter when folded, which can allow the balloon to navigate and cross tighter lesions.

[0064] Fig. 8B illustrates the distal end of an IVL catheter 850. Catheter 850 is in most respect similar to catheter 800 and can have all the same variations in different embodiments. Catheter 850 includes a catheter shaft having an outer member 802 with a distal end 804 and a proximal end (not shown in this drawing, but see, e.g., Figs. 3-4). The outer member has within it a lumen 806. An inner member 808 is positioned within lumen 806 and has a distal end 809 and a proximal end (also not shown in this drawing, but see, e.g., Figs. 3-4). In some embodiments, inner member 808 can include a guidewire lumen (not shown) to accommodate a guidewire. Emitters 810 are positioned on inner memberDocket No. 23812.52a 12808 and a balloon 852 is positioned at the distal end of the catheter. Balloon 852 has a proximal end 814 attached to distal and 804 of outer member 802, and distal end 816 is attached to inner member 808 at or near the distal end 809.

[0065] The primary difference between catheter 800 and catheter 850 is the shape of the balloon 852. Balloon 852 has two principal parts: a distal shoulder 818 and a proximal shoulder 822. Distal shoulder 818 tapers distally, meaning that its radial dimension decreases in the distal direction so that the distal shoulder has an angle A relative to inner member 808. In one embodiment angle A can have a value equal to or less than 45 degrees, but other embodiments need not be limited to this range. Proximal shoulder 822 tapers proximally, meaning that its radial dimension decreases in the proximal direction or, put differently, its radial dimension increases in the distal direction. The proximal shoulder has a proximal shoulder angle B relative to inner member 808. In embodiments of balloon 852, proximal shoulder angle B is greater than distal shoulder angle A; that is, the distal shoulder is sharper or narrower than the proximal shoulder, or the proximal shoulder is blunter than the distal shoulder. Balloon 852 differs from balloon 812 mostly in that it omits intermediate section 820. In balloon 852, then, distal shoulder 818 connects directly to proximal shoulder 822 at an apex 854, so that the apex is the part of the balloon with maximum radial dimension. As in balloon 812, in balloon 852 the tapered distal and proximal shoulders can help reduce distal crossing profile and maximize calcium contact, especially on the proximal end. Among other things, the tapered shoulders reduce the amount of material needed to form the balloon, thus creating less bulk that must cross a lesion.

[0066] Fig. 9 illustrates an embodiment of the distal end of an IVL catheter 900. Catheter 900 includes a balloon at or near its distal end with features that enhance crossability. The catheter includes a catheter shaft having an outer member 902 with a distal end 904 and a proximal end that is not shown in this drawing (but see, e.g., Figs. 3-4). The outer member has within it a lumen 906. An inner member 908 is positioned within outer lumen 906 and has a distal end 909 and a proximal end that is not shown in this drawing. In some embodiments, inner member 908 can include a guidewire lumen (not shown) to accommodate a guidewire.

[0067] As in IVL catheters 800 and 850, one or more emitters 910 are positioned on inner member 808 between the distal end 909 of the inner member and where the inner member exits from lumen 906. In the illustrated embodiment the emitters are positioned directly on the inner member, but in other embodiments there can be intervening elements betweenDocket No. 23812.52a 13the emitters and the inner member, and in still other embodiments the emitters can be positioned somewhere other than the inner member. The illustrated embodiment includes four emitters 910, but other embodiments can include more or less emitters than shown. And, as in IVL catheters 800 and 850, in the illustrated embodiment of catheter 900 the emitters are uniformly spaced (i.e., the inter-emitter distance is constant) but in other embodiments they need not be uniformly spaced.

[0068] A balloon 912 is positioned at the distal end of the catheter. The proximal end 914 of balloon 912 is attached to distal end 904 of outer member 902 and the distal end 916 of the balloon is at a position more distal than distal end 909 of inner member 908. In the illustrated configuration, balloon 912 substantially surrounds emitters 910 so that, when the balloon is inflated, acoustic energy (e.g., pressure waves) from emitters 910 travels through the fluid that fills the balloon, and through the balloon itself, to the lesion being disrupted or modified.

[0069] Balloon 912 has four principal parts: a proximal shoulder 918, an intermediate section 920, a distal shoulder 922, and an elongated tip 924. Proximal shoulder 918 tapers proximally, meaning that its radial dimension decreases in the proximal direction or, put differently, its radial dimension increases in the distal direction Distal shoulder 922 tapers distally, meaning that its radial dimension decreases in the distal direction. Intermediate section 820 connects the distal and proximal shoulders. In the illustrated embodiment intermediate section 820 has a substantially constant radial dimension, but in other embodiments its radial dimension need not be constant. The tapered distal and proximal shoulders can help reduce distal crossing profile and maximize calcium contact, especially on the proximal end. Among other things, the tapered shoulders reduce the amount of material needed to form the balloon, thus creating less bulk that must cross a lesion.

[0070] Elongated tip 924 is connected to distal shoulder 922 and projects distally from the distal shoulder 922 to a distal tip end 916 that is ahead of (i.e., more distal than) distal end 909 of inner member 908. In various embodiments, the longitudinal dimension Lt of the tip can be between 10 percent and 50 percent of the overall longitudinal dimension L of balloon 912, but in other embodiments dimension Lt need not be within this range. Similarly, in various embodiments, the radial dimension dt of tip 924 can be between 10 percent and 50 percent of the radial dimension D of balloon 912, but in other embodiments dimension Lt need not be within this range. In the illustrated embodiment, tip 924 is torpedo-shaped, with a substantially constant radial dimension dt and a blunt tip end 916, but in other embodiments the tip 924 can be tapered (i.e., radial dimension dt need not beDocket No. 23812.52a 14constant and can, for instance, decrease in the distal direction) and the tip need not be blunt. In embodiments of IVL catheter 900 that use a guidewire, distal tip end 916 can include a hole (not shown) to allow the guidewire to be pushed through and ahead of distal tip 916. The elongated tip can guide the balloon through a lumen and calcium deposits., and the torpedo-shaped tip may be more deliverable than a rounded, blunt tip that can snag or be resisted by lesion.

[0071] In various embodiments, balloon 912 can have the same constructions described above for balloons 812 and 852: in one embodiment it can be a high-pressure non-compliant balloon formed of a harder (i.e., higher durometer) material such as nylon, but in other embodiments the balloon can be formed of softer materials to allow it to conform to the lesion and in particular, the balloon material can be selected to allow the balloon to conform to irregularly-shaped lesions. In still other embodiments, the balloon can be a multi-layer balloon with two or more layers of material. The balloon can also be enhanced to improve crossability by forming the balloon in a low profile. In one embodiment, for instance, the balloon can be heat-set to have a small diameter when folded, which can allow the balloon to navigate and cross tighter lesions.

[0072] Fig. 10 illustrates another embodiment of the distal end of an IVL catheter 1000. Catheter 1000 includes a balloon at or near its distal end with features that enhance crossability. The catheter includes a catheter shaft having an outer member 1002 with a distal end 1004 and a proximal end that is not shown in this drawing (but see, e.g., Figs.3-4). The outer member has within it a lumen 1006. An inner member 1008 is positioned within outer lumen 1006 and has a distal end 1009 and a proximal end that is also not shown in this drawing. In some embodiments, inner member 1008 can include a guidewire lumen (not shown) to accommodate a guidewire.

[0073] As in IVL catheters 800 and 850, one or more emitters 1010 are positioned on inner member 1008 between the distal end 1009 of the inner member and where the inner member exits distal end 1004 of the outer member. In the illustrated embodiment the emitters are positioned directly on the inner member, but in other embodiments there can be intervening elements between the emitters and the inner member, and in still other embodiments the emitters can be positioned somewhere other than the inner member. The illustrated embodiment includes four emitters 1010, but other embodiments can include more or less emitters than shown. And, as in IVL catheters 800, 850, and 900, in the illustrated embodiment of catheter 1000 the emitters are uniformly spaced (i.e., the interemitter distance is constant) but in other embodiments they need not be uniformly spaced.Docket No. 23812.52a 15

[0074] A balloon 1012 is positioned at the distal end of the catheter. The proximal end 1014 of balloon 1012 is attached to distal and 1004 of outer member 1002, and distal end 1016 is attached to inner member 1008 at or near the distal end 1009. In the illustrated configuration, balloon 1012 substantially surrounds emitters 1010 so that, when the balloon is inflated, acoustic energy from emitters 1010 travels through the fluid that fills the balloon and through the balloon itself to the lesion being disrupted or modified.

[0075] Balloon 1012 has multiple chambers 1018. The illustrated embodiment includes four chambers 1018, but other embodiments can include more or less chambers than shown. In one embodiment, chambers 1018 are separate and independent, so that each chamber can be inflated, deflated, and otherwise controlled independently of the other chambers. In other embodiments chambers 1018 can instead all be fluidly connected chambers of a single balloon, so that all chambers inflate when fluid is pumped into the balloon through the inflation (see, e.g., Fig. 7) lumen. When chambers 1018 are all part of the same balloon, they need not inflate simultaneously. For instance, the balloon 1012 can be structured so that when fluid is pumped in the chambers inflate in a sequence, starting for instance with the most proximal chamber and ending with the most distal chamber. But other sequences are possible in other embodiments.

[0076] In the illustrated embodiment, each chamber 1018 is positioned around a single corresponding emitter 1010. The result is a one-to-one correspondence between emitters and chambers, so that when pulsed each emitter transmits acoustic energy through its corresponding balloon. But other embodiments can instead have a many-to-one correspondence between emitters and chambers; that is, more than one emitter in each chamber or more than one chamber per emitter. Each chamber 2018 has a radial dimension D and a longitudinal dimension L. In the illustrated embodiment chambers 2018 are substantially spherical, so that D ~ L. But in other embodiments the chambers need not be spherical (i.e., DL) and not all chambers need have the same radial dimension or longitudinal dimensions. Similarly, in the illustrated embodiment there is a uniform (i.e., constant) non-zero distance 5 between chambers, but in other embodiment the interchamber distance 5 need not be uniform. Advantageously, the non-zero inter-chamber separation 6 can allow the IVL catheter 1000 to be more flexible in bending, allowing it to track better through a target vessel. The separation (inter-chamber distance 5 ) allows for a smaller diameter flex region between the crimped chambers. The flex region in turnDocket No. 23812.52a 16allows reduced bending stiffness overall and thus improved deliverability into tortuous anatomy, especially in the distal regions of the balloon.

[0077] In various embodiments, balloon 1012 can have the same constructions described above for balloons 812, 852, and 912: in one embodiment it can be a high-pressure non-compliant balloon formed of a harder (i.e., higher durometer) material such as nylon, but in other embodiments the balloon can be formed of softer materials to allow it to conform to the lesion and in particular, the balloon material can be selected to allow the balloon to conform to irregularly-shaped lesions. In still other embodiments, the balloon can be a multi-layer balloon with two or more layers of material. The balloon can also be enhanced to improve crossability by forming the balloon in a low profile. In one embodiment, for instance, the balloon can be heat-set to have a small diameter when folded, which can allow the balloon to navigate and cross tighter lesions.

[0078] Fig. 11 illustrates an embodiment of a distal end of an IVL catheter 1100. Catheter 1100 includes a catheter shaft having an outer member 1102 with a distal end 1104 and a proximal end that is not shown in this drawing (but see, e.g., Figs. 3-4) and an interior lumen (not shown). An inner member 1108 is positioned within the outer member’s lumen and has a distal end 1109 and a proximal end that is also not shown in this drawing. In some embodiments, inner member 1108 can include a guidewire lumen (not shown) to accommodate a guidewire. As in other embodiments, emitters (not shown) are positioned inside the balloon. In an embodiment the emitters can be positioned directly on the inner member, as shown in the embodiment above, but in other embodiments there can be intervening elements between the emitters and the inner member, and in still other embodiments the emitters can be positioned somewhere other than the inner member.

[0079] Catheter 1100 includes a balloon 1112 positioned at or near its distal end that, when deflated or partially inflated, can be folded or wrapped around an axis of the catheter in a way that enhances column strength, thus improving pushability (i.e., the catheter and / or the balloon’s ability to carry a compression load without buckling) and crossability. The balloon can be wrapped in a circumferential direction or in a direction with both circumferential and longitudinal components. In the illustrated embodiment the balloon is twisted about the longitudinal direction so that it wraps both circumferentially and longitudinally, resulting in a wrap or fold that is spiral or helical. As a result of wrapping or folding, a cross-sectional profile at any longitudinal location along the balloon is eccentric or non-axisymmetric relative to the inner member.Docket No. 23812.52a 17

[0080] Maintaining the balloon folds in a wrapped configuration, spiral or otherwise, can be important to promoting pushability (i.e., column strength) when the balloon is deflated or partially inflated, so that the balloon can more easily be pushed into a through a lesion. In an embodiment, an adhesive may be applied between the folds to maintain wrap integrity during delivery. Energy, such as ultraviolet (UV) energy, can be applied during wrapping to activate the adhesive or otherwise activate the balloon surfaces to promote adhesion. In various embodiments, balloon 1112 can have any of the constructions discussed above for balloons 812, 852, 912, and 1012.

[0081] Figs. 12A-12E illustrate embodiments of balloon pleat configurations that can be wrapped, for instance as shown in Fig. 11, for improved pushability and crossability.

[0082] Fig. 12A illustrates a balloon configuration 1200 including embodiments of pleats to improve its folding or wrapping, as shown for example in Fig. 11. In balloon configuration 1200, the balloon is positioned around inner member 1202 and includes a first pleat 1204 with first radial dimension R1 and an opposite pleat 1206 with a second radial dimension R2 than an opposite pleat 1206. In the illustrated embodiment R1 and R2 are unequal, meaning that the balloon is asymmetric. Balloon 1200 can include other features, such as a making the material of the second pleat thicker than the material of the first pleat, so that second pleat 1206 expands less when inflated and can better withstand the acoustic energy (e.g., pressure waves or shocks) generated when the emitters (not shown in this drawing, but positioned on inner member 1202 as described above for other embodiments) are pulsed. As in the embodiment of Fig. 11, an adhesive can be applied between pleats to maintain wrap integrity.

[0083] Fig. 12B illustrates a balloon configuration 1220 including embodiments of pleats to improve its folding or wrapping. In balloon configuration 1220, the balloon is positioned around inner member 1222 and includes a first set of pleats that form a square-wave pattern with wings or peaks 1224 and troughs 1226. The balloon also includes a second set of pleats that form a square-wave pattern with wings or peaks 1228 and troughs 1230. The first and second sets of pleats are longitudinally offset from each other, so that the peaks of one set of pleats are substantially at the same longitudinal locations as the troughs of the other set of pleats. By positioning the peaks and troughs this way, when wrapped circumferentially the peaks from one set fold neatly into the troughs of the other set. Thus, peak 1224 folds into trough 1230, peak 1228 folds into trough 1226, and so on, as illustrated by the arrows in the figure. The result is a decreased cross-sectional profile ofDocket No. 23812.52a 18the balloon when wrapped. As in the embodiment of Fig. 11, an adhesive can be applied between pleats to maintain wrap integrity.

[0084] Fig. 12C illustrates a balloon configuration 1240 including embodiments of pleats to improve its folding or wrapping. Balloon configuration 1240 is substantially similar to balloon configuration 1220. The principal difference is that in configuration 1240 the pleats are shaped into a curved-wave pattern instead of a square-wave pattern. The balloon is positioned around inner member 1242 and includes a first set of pleats that form a curved-wave pattern with wings or peaks 1244 and troughs 1246. The balloon also includes a second set of pleats that form a curved-wave pattern with wings or peaks 1248 and troughs 1250. The first and second sets of pleats are longitudinally offset from each other, so that the peaks of one set of pleats are substantially at the same longitudinal locations as the troughs of the other set of pleats. By positioning the peaks and troughs this way, when wrapped circumferentially the peaks from one set fold neatly into the troughs of the other set. Thus, peak 1244 folds into trough 1250, peak 1248 folds into trough 1246, and so on, as illustrated by the arrows in the figure. The result is a decreased cross-sectional area of the balloon when wrapped. As in the embodiment of Fig. 11, an adhesive can be applied between pleats to maintain wrap integrity.

[0085] Fig. 12D illustrates a balloon configuration 1260 including embodiments of pleats to improve its folding or wrapping. In balloon configuration 1260, the balloon is positioned around inner member 1262 and includes at least a first pleat 1204 and a second pleat 1206. To reduce the amount of material in the balloon, and thus decrease the profile of the balloon when wrapped or folded, the distal edges 1268 and 1270 of the pleats, which form the distal shoulder of the balloon, are made concave. Similarly, the proximal edges 1272 and 1274 of the pleats, which will form the proximal shoulder of the balloon, can be made concave. As in the embodiment of Fig. 11, an adhesive can be applied between pleats to maintain wrap integrity.

[0086] Fig. 12E illustrates various embodiments of pleat cross-sections. The crosssections show how the pleats look when viewed from the proximal or distal ends of the balloon. In pleat cross-sections 1280, 1282, and 1284, all the pleats have substantially the same radial dimension and the pleats have substantially uniform angular spacing around the circumference. Thus, pleat cross-section 1280 has three pleats uniformly spaced substantially 120 degrees apart; pleat cross-section 1282 has four pleats uniformly spaced substantially 90 degrees apart, and pleat cross-section 1280 has five pleats uniformly spaced substantially 72 degrees apart. Other embodiments can, of course, have more orDocket No. 23812.52a 19less pleats than shown. When folding or wrapping the balloon, each pleat is circumferentially folded or wrapped into an adjacent pleat, as illustrated by the arrows in the figure. Any of the illustrated cross-sections can be used with any of the balloon configurations described above.

[0087] Pleat cross-section 1286 has three pleats, each of different radial dimension, and they are irregularly angularly spaced. When folding or wrapping pleat-cross 1286, to minimize the cross-section of the balloon when folded or wrapped, it can be desirable to wrap or fold the pleats in order of radial dimension, so that the shortest pleat is folded into the next longest pleat, which is then wrapped into the next-longest pleat, and so on, as illustrated by the arrows in the figure. Other embodiments can, of course, have more or less pleats than shown, and these cross-sections can be used with any of the balloon configurations described above.

[0088] Figs. 13 A and 13B illustrate another embodiment of a distal portion of an intravascular lithotripsy (IVL) catheter 1300. In this embodiment, the IVL catheter includes a catheter shaft having an outer member 1302 and an inner member 1304. As in other embodiments described herein, the inner member 1304 can define or include a guidewire lumen through which a guidewire may be advanced to facilitate tracking and positioning of the catheter within a patient’s vasculature.

[0089] A balloon 1308 is mounted on the catheter shaft such that a proximal end of the balloon is attached to the distal end of the outer member 1302 and a distal end of the balloon is attached to the inner member 1304. The balloon 1308 surrounds at least a distal portion of inner member 1304 and defines an interior space for receiving inflation fluid and housing one or more emitters. When inflated, balloon 1308 can be expanded against a lesion in a manner similar to the other balloon embodiments described above.

[0090] The balloon 1308 includes a plurality of chambers and passageways 1310, 1312 that helically spiral around the longitudinal axis of inner member 1304. The chambers and passageways 1310, 1312 extend both longitudinally and circumferentially, generating a helical geometry that wraps the balloon 1308 around the inner member 1304. In the illustrated embodiment, the plurality of chambers and passageways includes two inflation chambers 1310 and two perfusion passageways 1312. The chambers and passageways 1310, 1312 alternate around the circumference of the balloon, with each inflation chamber 1310 being separated from the next inflation chamber 1310 by a perfusion passageway 1312, and vice versa. The alternating pattern produces a balanced arrangement of fluid-inflatable and blood-perfusion pathways around the inner member.Docket No. 23812.52a 20

[0091] The helical configuration can promote several advantages. For example, the alternating and spiraled chambers and passageways may distribute radial expansion forces more uniformly when the balloon 1308 is inflated. Additionally, the helical geometry may improve the deliverability of the catheter through tortuous anatomy, because the spiral pattern can allow localized regions of the balloon 1308 to flex more readily when the catheter bends.

[0092] Each inflation chamber 1310 is configured to receive inflation fluid from an inflation lumen formed in the catheter shaft, such as the inflation lumen described above with respect to Fig. 7. As shown in Fig. 13B, one or more IVL emitters 1306 are positioned within each inflation chamber 1310. Each emitter 1306 may be mounted on, or positioned adjacent to, the outer surface of inner member 1304. In various embodiments, the emitters receive electrical pulses from the IVL control system, via electrical conductors extending through the catheter shaft, and generate pressure waves (e.g., shock waves) when pulsed.

[0093] Locating an emitter 1306 within each inflation chamber 1310 allows the emitter to be surrounded by fluid during activation, enhancing propagation of the pressure wave through the balloon wall and into adjacent vascular tissue. The spiral placement of the inflation chambers can also influence how the emitted pressure waves interact with the lesion, enabling circumferential distribution of acoustic energy around the vessel lumen.

[0094] Each perfusion passageway 1312 is configured to allow blood to perfuse through the balloon 1308 when the inflation chambers 1310 are inflated. In the embodiment of Fig.13 A, each perfusion passageway 1312 includes a proximal opening and a distal opening 1314. These openings permit blood flow into the proximal end of the perfusion passageway and out through the distal end, thereby maintaining at least partial antegrade perfusion even when the balloon 1308 is fully expanded within a vessel. Maintaining blood flow during balloon inflation may be particularly beneficial during prolonged IVL procedures, reducing ischemic risk while the lesion is being modified.

[0095] In some embodiments, perfusion passageways 1312 may remain substantially uninflated or only partially inflated during inflation of the balloon 1308, so that they maintain an open lumen for blood flow while the inflation chambers 1310 generate apposition against the lesion.

[0096] As further shown in Figs. 13 A and 13B, the exterior of balloon 1308 can include one or more channels 1316. These channels may correspond to the valleys formed at interfaces between adjacent chambers and passageways 1310, 1312. The channels may extend helically or longitudinally along the balloon surface, and can provide additionalDocket No. 23812.52a 21flow paths for blood to move past the balloon 1308 when it is inflated. In some embodiments, the channels 1316 enhance perfusion by maintaining low-profile external grooves that permit blood to pass between the chamber and passageway structures.

[0097] During use, the balloon 1308 can be positioned across a lesion on a guidewire extending through inner member 1304. When the inflation chambers 1310 are inflated, the emitters 1306 can be pulsed to generate pressure waves that transmit radially outward from the inflation chambers toward calcified lesion material. At the same time, perfusion passageways 1312 and external channels 1316 permit blood to flow through or around the balloon 1308. Thus, unlike conventional balloons that occlude flow completely, this embodiment allows therapeutic IVL energy delivery while maintaining perfusion, which may reduce ischemic complications and enable longer or staged lithotripsy cycles.

[0098] In addition, the helical arrangement of chambers and passageways 1310, 1312 may provide improved flexibility and bending compliance along the balloon length, which can facilitate navigation through tortuous or highly stenotic anatomy. The alternating inflation chamber and perfusion passageway design also provides circumferential mechanical stability during expansion, while reducing the overall balloon mass and potentially improving crossability.

[0099] Figs. 14A and 14B illustrate another embodiment of a distal portion of an intravascular lithotripsy (IVL) catheter 1400. As in other embodiments described herein, the IVL catheter includes a catheter shaft having an outer member 1402 and an inner member 1404. The inner member 1404 can include a guidewire lumen extending therethrough, allowing the catheter to be tracked to a target lesion within a blood vessel.

[0100] A balloon 1406 is positioned at or near the distal end of the catheter shaft. A proximal end of the balloon 1406 is attached to the distal end of outer member 1402, while the balloon at least partially surrounds a distal region of inner member 1404. In this embodiment, balloon 1406 is not formed as a uniform cylindrical structure, but instead includes a plurality of eccentric lobes 1406a, 1406b, and 1406c disposed along the length of the inner member 1404.

[0101] Each lobe 1406a, 1406b, 1406c extends radially outward from the inner member 1404 in an eccentric manner. That is, each lobe extends circumferentially around only a portion of the inner member rather than fully surrounding it or extends further to one side of the inner member 1404 than another side. In various embodiments, each lobe extends around approximately 25%, 33%, 50%, or another partial circumferential extent of the inner member. As a result, each lobe protrudes radially more in one circumferentialDocket No. 23812.52a 22direction than in another, giving each lobe section of the balloon 1406 a non-axisymmetric, eccentric profile.

[0102] The eccentric lobes 1406a, 1406b, 1406c can be separated both circumferentially and longitudinally. For example, as illustrated, the lobes 1406a, 1406b, and 1406c are circumferentially offset from one another around inner member 1404. In an embodiment including three lobes, the lobes may be circumferentially offset by about 120 degrees from each other, so that the overall balloon structure 1406 spans the full circumference of the inner member when considered collectively, even though each individual lobe spans only a portion.

[0103] In some embodiments, at least portions of the lobes 1406a, 1406b, 1406c are longitudinally spaced apart from one another along the length of inner member 1404, as shown in Fig. 14A. The lobes may therefore be arranged so that no two lobes occupy the same circumferential position at the same longitudinal location. This spacing can create open longitudinal flow paths around the inflated balloon, enabling partial perfusion during lithotripsy, as shown in Fig. 14A.

[0104] The combination of (i) the eccentric radial extension of each lobe, (ii) the circumferential offset of adjacent lobes, and (iii) the longitudinal spacing between lobes, produces a balloon configuration that maintains a reduced obstruction profile even when inflated. Fluid pathways around and between lobes can permit blood to flow around the balloon during inflation, which may reduce ischemic burden during extended lithotripsy cycles.

[0105] One or more IVL emitters 1408 may be positioned within each eccentric lobe. Each emitter can be mounted on or adjacent to the outer surface of inner member 1404 at locations that correspond to the interior of the lobes. When pulsed, the emitters generate acoustic pressure waves that propagate through the inflation fluid within each lobe and through the balloon wall to disrupt calcified lesions.

[0106] The eccentric geometry of the lobes can influence the directionality of the emitted acoustic energy. Because each lobe extends circumferentially over only part of the inner member, the pressure waves generated within a given lobe may be directed preferentially toward the tissue adjacent to that lobe. The circumferentially-offset arrangement of the lobes can therefore provide multi-directional acoustic coverage of the lesion while still allowing perfusion pathways to remain open.

[0107] In various embodiments, balloon 1406 can be formed of compliant, semi-compliant, or non-compliant materials, including polyurethane, nylon, or multi-layerDocket No. 23812.52a 23constructions as described above for other balloons. The balloon may be heat-set or otherwise formed so that the eccentric lobes maintain their geometry when folded, partially inflated, and fully inflated.

[0108] Fig. 15 illustrates an embodiment of a process 1500 for using a IVL catheter. The process is applicable to any catheter embodiment described herein. The process starts at block 1502. At block 1504, the IVL catheter is inserted into a blood vessel and navigated through the blood vessel until it reaches a lesion. Upon reaching the lesion, at block 1506 a guidewire, if present, is pushed through the lesion until the lesion is penetrated. At block 1508, the IVL catheter is then pushed through the lesion, following the guidewire, until the balloon has penetrated through the lesion. Once through the lesion, at block 1510 the balloon is inflated and at block 1512 the emitters are pulsed to generate pressure waves to modify the lesion. The balloon may be enhanced to target eccentric calcifications. For example, a balloon may be deliverable subintimally to allow shock waves to disrupt eccentric lesions. A guidewire may be tracked through the target vessel and inserted subintimally below the eccentric lesion, and the balloon may then be tracked into place to deliver the disruptive shock waves.

[0109] At block 1514, the modification of the lesion is checked to see if it was sufficiently modified by the balloon and the pressure waves. If at block 1514 the lesion is sufficiently modified, the process advances to block 1516, where the surgeon can perform any needed follow-up procedures, such as inserting a stent. When the follow-on procedure, if any, is complete, the process moves to block 1518, where the IVL catheter is withdrawn from the patient, and then advances to block 1520, where the process stops. But if at block 1514 the lesion was not sufficiently modified by the IVL catheter, then at block 1522 the emitters are pulsed again. From block 1522, the process returns to block 1514 to check the modification of the lesion. This sequence of blocks 1514 and 1522 can be repeated until the lesion is satisfactorily modified.

[0110] Fig. 16 illustrates an embodiment of a process 1600 for using an IVL catheter. The process is applicable to any catheter embodiment described herein. The process starts at block 1602. At block 1604, the IVL catheter is inserted into a blood vessel and navigated through the blood vessel until it reaches a lesion. Upon reaching a lesion, at block 1606 a guidewire, if present, is pushed through the lesion until the lesion is penetrated. At block 1608, the distal end of the balloon is inserted into the lesion, at block 1610 the balloon is at least partially inflated, and at block 1612 selected emitters inside the balloon can be pulsed. In one embodiment only a single emitter can be pulsed, for instanceDocket No. 23812.52a 24the most distal emitter, but in other embodiments other combinations of emitters, such as the two or three most distal emitters, can be pulsed simultaneously or in a sequence.

[0111] At block 1614, the modification of the lesion is checked to see if it was sufficiently modified by pulsed emitters at block 1612. If at block 1614 the lesion was not sufficiently modified, then the process returns to block 1612 to pulse the selected emitters to further modify the lesion. The emitters selected for pulsing need not be the same set of emitters every time the process returns to block 1612. But if at block 1614 the lesion is sufficiently modified, the process advances to block 1616, where the balloon is further advanced into the lesion.

[0112] At block 1618 the process checks whether the balloon is fully through the lesion. If at block 1618 the ballon is not fully through the lesion, the process returns to block 1612 and pulses the emitters. But if at block 1618 the ballon is fully through the lesion, then the process advances to block 1620, where it fully inflates the balloon (if not already fully inflated) and pulses the full set of emitters inside the balloon to fully modify the lesion in preparation for any follow-on procedures. The balloon may be enhanced to target eccentric calcifications. For example, a balloon may be deliverable subintimally to allow shock waves to disrupt eccentric lesions. A guidewire may be tracked through the target vessel and inserted subintimally below the eccentric lesion, and the balloon may then be tracked into place to deliver the disruptive shock waves.

[0113] At block 1622 the process checks whether the lesion is sufficiently modified for the follow-on procedure. If at block 1622 the lesion is not sufficiently modified, the process returns to block 1620, where the balloon’s inflation can be changed (i.e., it can be deflated or can be inflated further if not already fully inflated) and the emitters pulsed again. But if at block 1622 the lesion is sufficiently modified for the follow-on procedure, the process advances to block 1624 and performs the follow-on procedure. When the procedure at block 1624 is complete, the process advances to block 1626, where the IVL catheter is withdrawn from the patient, and then on to block 1628, where the process stops.

[0114] According to the present disclosure, where the one or more lithotripsy emitters are configured as electrodes, the applied voltage during an exemplary lithotripsy procedure may be from about 2000 V to 5000 V, or from about 2500 V to about 3500 V (e.g., about 3000 V). Laser or other optical lithotripsy emitters may alternatively be used to generate the desired acoustic shock wave. The inflation medium can be a saline solution, e.g., mixed with contrast media. An electrode generated plasma arc (or an intermediate targetDocket No. 23812.52a 25heated by the laser energy) may result in vaporization and cavitation within the inflation medium used to inflate the lithotripsy balloon and such cavitation may contribute at least in part to generation of the shock wave. The generated shock wave may exert a pressure of at least 30 atm, at least 35 atm, at least 40 atm, at least 45 atm, such as from 45 atm to 55 atm on the vessel wall, so as to break up the calcified tissue. The generated shock wave may exert at least one of compressive, shearing, spallation, squeezing or cavitation forces on the vessel wall, which aids in disrupting and breaking up the calcified tissue. The generated shock wave propagates through the inflation medium used to inflate the inflatable balloon, through the balloon, and into the wall defining the vessel lumen, so as to break up the calcified tissue that is associated with the vessel wall.

[0115] It is contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments disclosed above may be made and still fall within one or more of the embodiments. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with an embodiment can be used in all other embodiments set forth herein. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed embodiments. Thus, it is intended that the scope of the present disclosure herein disclosed should not be limited by the particular disclosed embodiments described above. Moreover, while the present disclosure is susceptible to various modifications, and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the present disclosure is not to be limited to the particular forms or methods disclosed, but to the contrary, the present disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the various embodiments described and the appended claims. Any methods disclosed herein need not be performed in the order recited. The methods disclosed herein include certain actions taken by a practitioner; however, they can also include any third-party instruction of those actions, either expressly or by implication.

[0116] Any ranges disclosed herein also encompass any and all overlap, subranges, and combinations thereof. Language such as “up to,” “at least,” “greater than,” “less than,” “between,” and the like includes the number recited. Numbers preceded by a term such as “approximately”, “about”, or “substantially” as used herein include the recited numbers (e.g., about 10% includes 10%), and also represent an amount close to the stated amount that still performs a desired function or achieves a desired result. ForDocket No. 23812.52a 26example, the terms “approximately”, “about”, and “substantially” may refer to an amount that is within 10% of, within 5% of, within 1% of the stated amount.

[0117] For purposes of the present disclosure and appended claims, the conjunction “or” is to be construed inclusively (e.g., “an apple or an orange” would be interpreted as “an apple, or an orange, or both”; e.g., “an apple, an orange, or an avocado” would be interpreted as “an apple, or an orange, or an avocado, or any two, or all three”), unless: (i) it is explicitly stated otherwise, e.g., by use of “either...or,” “only one of,” or similar language; or (ii) two or more of the listed alternatives are mutually exclusive within the particular context, in which case “or” would encompass only those combinations involving non-mutually-exclusive alternatives. For purposes of the present disclosure and appended claims, the words “comprising,” “including,” “having,” and variants thereof, wherever they appear, shall be construed as open-ended terminology, with the same meaning as if the phrase “at least” were appended after each instance thereof.

[0118] Following are some further example embodiments of the invention. These are presented only by way of example and are not intended to limit the scope of the invention in any way. Further, any example embodiment can be combined with one or more of the example embodiments.

[0119] Embodiment 1. An intravascular lithotripsy (IVL) catheter comprising: a catheter shaft having a proximal end and a distal end; a balloon positioned at or near the distal end of the catheter shaft, the balloon having a distal end and a proximal end, wherein the balloon includes a distal shoulder at the distal end of the balloon and a proximal shoulder at the proximal end of the balloon, the distal shoulder and the catheter shaft forming a shoulder angle that opens proximally and is lower than a shoulder angle formed between the proximal shoulder and the catheter shaft and that opens distally; and a plurality of spaced-apart emitters positioned inside the balloon.

[0120] Embodiment 2. The IVL catheter of embodiment 1 wherein the distal shoulder is directly connected to the proximal shoulder at an apex.

[0121] Embodiment 3. The IVL catheter of embodiment 1 wherein the balloon further comprises an intermediate section connecting the distal shoulder to the proximal shoulder.

[0122] Embodiment 4. The IVL catheter of embodiment 1 wherein the balloon further comprises an elongated tip that projects distally from the distal shoulder.Docket No. 23812.52a 27

[0123] Embodiment 5. The IVL catheter of embodiment 4 wherein the elongated tip has a longitudinal dimension between 10 percent and 50 percent of an overall longitudinal dimension of the balloon.

[0124] Embodiment 6. The IVL catheter of embodiment 4 wherein the elongated tip has a radial dimension between 10 percent and 50 percent of an overall radial dimension of the balloon.

[0125] Embodiment 7. The IVL catheter of embodiment 1 wherein the distal shoulder angle is less than or equal to 45 degrees.

[0126] Embodiment 8. The IVL catheter of embodiment 1 wherein the balloon is fluidly coupled to an inflation lumen formed in the catheter shaft.

[0127] Embodiment 9. An intravascular lithotripsy (IVL) catheter comprising: a catheter shaft having a proximal end and a distal end; a balloon positioned at or near the distal end of the catheter shaft, the balloon having a distal end and a proximal end, wherein the balloon includes a plurality of chambers; and a plurality of spaced-apart emitters positioned inside the balloon with each chamber of the balloon substantially surrounding at least a corresponding one of the plurality of emitters.

[0128] Embodiment 10. The IVL catheter of embodiment 9 wherein each chamber of the plurality of chambers is separately and independently inflatable.

[0129] Embodiment 11. The IVL catheter of embodiment 9 wherein each chamber of the plurality of chambers is in fluid communication with one or more adjacent chambers.

[0130] Embodiment 12. The IVL catheter of embodiment 11 wherein the balloon is fluidly coupled to an inflation lumen formed in the catheter shaft.

[0131] Embodiment 13. The IVL catheter of embodiment 9 wherein there is a nonzero longitudinal separation between each chamber and an adjacent chamber.

[0132] Embodiment 14. The IVL catheter of embodiment 9 wherein the plurality of chambers are all substantially spherical.

[0133] Embodiment 15. An intravascular lithotripsy (IVL) catheter comprising: a catheter shaft having a proximal end and a distal end; a balloon positioned at or near the distal end of the catheter shaft, wherein, when deflated, the balloon is circumferentially wrapped around the catheter shaft so that a cross-sectional profile at any longitudinal location along the balloon is eccentric or non-axisymmetric relative to a central axis of the catheter shaft, such that the balloon extends laterally further to one side of the catheter shaft than another at any longitudinal location along the balloon; and a plurality of spaced-apart emitters positioned inside the balloon.Docket No. 23812.52a 28

[0134] Embodiment 16. The IVL catheter of embodiment 15 wherein the balloon is wrapped both circumferentially and longitudinally, so that the balloon appears helical when wrapped.

[0135] Embodiment 17. The IVL catheter of embodiment 15 wherein the balloon comprises a plurality of pleats.

[0136] Embodiment 18. The IVL catheter of embodiment 17 wherein, when wrapped, each pleat in the plurality of pleats is wrapped against an adjacent pleat.

[0137] Embodiment 19. The IVL catheter of embodiment 18 wherein each pleat is secured to the adjacent pleat with an adhesive.

[0138] Embodiment 20. The IVL catheter of embodiment 17 wherein each pleat comprises a wave pattern with peaks and troughs and wherein adjacent pleats are longitudinally offset so that the peaks in one pleat are longitudinally aligned with the troughs in an adjacent pleat.

[0139] Embodiment 21. The IVL catheter of embodiment 20 wherein the wave pattern is a square-wave pattern or a curved-wave pattern.

[0140] Embodiment 22. The IVL catheter of embodiment 17 wherein each pleat in the plurality of pleats has a different radial dimension.

[0141] Embodiment 23. The IVL catheter of embodiment 17 wherein the balloon has a distal shoulder and wherein a part of each pleat that forms a distal shoulder of the balloon is concave.

[0142] Embodiment 24. The IVL catheter of embodiment 15 wherein the balloon is fluidly coupled to an inflation lumen formed in the catheter shaft.

[0143] Embodiment 25. An intravascular lithotripsy (IVL) catheter comprising: a catheter shaft having a proximal end and a distal end, the catheter shaft including an outer member and an inner member, the inner member defining a guidewire lumen; and a balloon mounted at or near the distal end of the catheter shaft, the balloon comprising: a proximal end attached to the distal end of the outer member; a distal end attached to the inner member; and a plurality of chambers and passageways formed in the balloon and helically arranged around the inner member.

[0144] Embodiment 26. The IVL catheter of embodiment 25, wherein the plurality of chambers and passageways comprise a plurality of inflation chambers and a plurality of perfusion passageways.

[0145] Embodiment 27. The IVL catheter of embodiment 26, wherein the inflation chambers and the perfusion passageways alternate around a circumference of the balloon.Docket No. 23812.52a 29

[0146] Embodiment 28. The IVL catheter of embodiment 26, wherein each inflation chamber surrounds at least one lithotripsy emitter positioned on or adjacent to the inner member.

[0147] Embodiment 29. The IVL catheter of embodiment 25, wherein each inflation chamber is in fluid communication with an inflation lumen formed in the catheter shaft.

[0148] Embodiment 30. The IVL catheter of embodiment 25, wherein each perfusion passageway comprises a proximal opening and a distal opening that allow blood to perfuse through the perfusion passageway during balloon inflation.

[0149] Embodiment 31. The IVL catheter of embodiment 25, wherein the balloon includes one or more exterior channels located between adjacent chambers.

[0150] Embodiment 32. The IVL catheter of embodiment 31, wherein the one or more exterior channels are configured to facilitate blood flow around the balloon when the balloon is inflated.

[0151] Embodiment 33. The IVL catheter of embodiment 25, wherein the plurality of chambers and passageways helically spiral along a longitudinal axis of the inner member.

[0152] Embodiment 34. The IVL catheter of embodiment 33, wherein the helical arrangement of the plurality of chambers and passageways extend along substantially an entire longitudinal length of the balloon.

[0153] Embodiment 35. The IVL catheter of embodiment 25, wherein the plurality of chambers and passageways comprises two inflation chambers and two perfusion passageways.

[0154] Embodiment 36. The IVL catheter of embodiment 25, wherein the balloon is shaped so that interfaces between adjacent chambers and passageways form exterior channels.

[0155] Embodiment 37. The IVL catheter of embodiment 26, wherein the perfusion passageway are configured to provide continuous antegrade blood perfusion during intravascular lithotripsy.

[0156] Embodiment 38. The IVL catheter of embodiment 25, wherein the balloon is configured such that activation of one or more emitters therein produces circumferentially distributed acoustic energy around a target lesion.Docket No. 23812.52a 30

[0157] Embodiment 39. The IVL catheter of embodiment 25, wherein the helical chamber and passageway arrangement increases bending flexibility of the balloon relative to a balloon having longitudinally aligned chambers.

[0158] Embodiment 40. The IVL catheter of embodiment 25, further comprising a plurality of lithotripsy emitters positioned inside the balloon, each emitter located within a corresponding inflation chamber.

[0159] Embodiment 41. The IVL catheter of embodiment 25, wherein at least one perfusion passageway and at least one inflation chamber extend helically with a common pitch around the inner member.

[0160] Embodiment 42. An intravascular lithotripsy (IVL) catheter comprising: a catheter shaft having a proximal end and a distal end, the catheter shaft including an outer member and an inner member, the inner member defining a guidewire lumen; and a balloon positioned at or near the distal end of the catheter shaft, the balloon having a proximal end attached to the outer member and a plurality of eccentric lobes formed in the balloon, each eccentric lobe extending circumferentially around only a portion of the inner member.

[0161] Embodiment 43. The IVL catheter of embodiment 42, wherein each eccentric lobe extends around between approximately 20 percent and 60 percent of a circumferential extent of the inner member.

[0162] Embodiment 44. The IVL catheter of embodiment 42, wherein adjacent eccentric lobes are circumferentially offset from one another.

[0163] Embodiment 45. The IVL catheter of embodiment 44, wherein the eccentric lobes are circumferentially offset by approximately 120 degrees relative to one another.

[0164] Embodiment 46. The IVL catheter of embodiment 42, wherein at least two of the eccentric lobes are longitudinally spaced apart along the inner member.

[0165] Embodiment 47. The IVL catheter of embodiment 42, wherein the plurality of eccentric lobes collectively extend circumferentially around the entire inner member.

[0166] Embodiment 48. The IVL catheter of embodiment 42, further comprising a plurality of lithotripsy emitters positioned inside the balloon, wherein at least one lithotripsy emitter is located within each eccentric lobe.

[0167] Embodiment 49. The IVL catheter of embodiment 48, wherein each lithotripsy emitter is mounted on or adjacent to an outer surface of the inner member.Docket No. 23812.52a 31

[0168] Embodiment 50. The IVL catheter of embodiment 42, wherein the eccentric lobes define flow paths between adjacent lobes that permit blood perfusion around the balloon when the balloon is inflated.

[0169] Embodiment 51. The IVL catheter of embodiment 42, wherein circumferential offset of the eccentric lobes provides open longitudinal channels for blood perfusion during intravascular lithotripsy.

[0170] Embodiment 52. The IVL catheter of embodiment 42, wherein at least one eccentric lobe is positioned to direct acoustic energy preferentially toward an eccentric lesion.

[0171] Embodiment 53. The IVL catheter of embodiment 42, wherein the balloon comprises a compliant or semi-compliant polymer configured to expand the eccentric lobes during inflation.

[0172] Embodiment 54. The IVL catheter of embodiment 42, wherein each eccentric lobe is a chamber that inflates independently from an adjacent eccentric lobe.

[0173] Embodiment 55. The IVL catheter of embodiment 42, wherein the eccentric lobes collectively define a non-axisymmetric balloon profile when the balloon is inflated.

[0174] Embodiment 56. The IVL catheter of embodiment 42, wherein longitudinal spacing and circumferential offset of the eccentric lobes increase bending flexibility of the balloon.

[0175] Embodiment 57. The IVL catheter of embodiment 42, wherein each eccentric lobe comprises a region of greater radial extension and a region of lesser radial extension relative to the inner member.

[0176] Embodiment 58. The IVL catheter of embodiment 42, wherein the eccentric lobes are arranged to produce multi-directional acoustic coverage of a target lesion.

[0177] The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.Docket No. 23812.52a 32

Claims

CLAIMSWhat is claimed is:

1. An intravascular lithotripsy (IVL) catheter comprising:a catheter shaft having a proximal end and a distal end;a balloon positioned at or near the distal end of the catheter shaft, the balloon having a distal end and a proximal end, wherein the balloon includes a distal shoulder at the distal end of the balloon and a proximal shoulder at the proximal end of the balloon, the distal shoulder and the catheter shaft forming a shoulder angle that opens proximally and is lower than a shoulder angle formed between the proximal shoulder and the catheter shaft and that opens distally; anda plurality of spaced-apart emitters positioned inside the balloon.

2. The IVL catheter of claim 1 wherein the distal shoulder is directly connected to the proximal shoulder at an apex.

3. The IVL catheter of claim 1 wherein the balloon further comprises an intermediate section connecting the distal shoulder to the proximal shoulder.

4. The IVL catheter of claim 1 wherein the balloon further comprises an elongated tip that projects distally from the distal shoulder.

5. The IVL catheter of claim 4 wherein the elongated tip has a longitudinal dimension between 10 percent and 50 percent of an overall longitudinal dimension of the balloon.

6. The IVL catheter of claim 4 wherein the elongated tip has a radial dimension between 10 percent and 50 percent of an overall radial dimension of the balloon.

7. The IVL catheter of claim 1 wherein the distal shoulder angle is less than or equal to 45 degrees.

8. The IVL catheter of claim 1 wherein the balloon is fluidly coupled to an inflation lumen formed in the catheter shaft.

9. An intravascular lithotripsy (IVL) catheter comprising:a catheter shaft having a proximal end and a distal end;a balloon positioned at or near the distal end of the catheter shaft, the balloon having a distal end and a proximal end, wherein the balloon includes a plurality of chambers; anda plurality of spaced-apart emitters positioned inside the balloon with each chamber of the balloon substantially surrounding at least a corresponding one of the plurality of emitters.Docket No. 23812.52a 3310. The IVL catheter of claim 9 wherein each chamber of the plurality of chambers is separately and independently inflatable.

11. The IVL catheter of claim 9 wherein each chamber of the plurality of chambers is in fluid communication with one or more adjacent chambers.

12. The IVL catheter of claim 11 wherein the balloon is fluidly coupled to an inflation lumen formed in the catheter shaft.

13. The IVL catheter of claim 9 wherein there is a non-zero longitudinal separation between each chamber and an adjacent chamber.

14. The IVL catheter of claim 9 wherein the plurality of chambers are all substantially spherical.

15. An intravascular lithotripsy (IVL) catheter comprising:a catheter shaft having a proximal end and a distal end;a balloon positioned at or near the distal end of the catheter shaft, wherein, when deflated, the balloon is wrapped around the catheter shaft so that a cross-sectional profile at any longitudinal location along the balloon is eccentric or non-axisymmetric relative to a central axis of the catheter shaft, such that the balloon extends laterally further to one side of the catheter shaft than another at any longitudinal location along the balloon, wherein the balloon is wrapped both circumferentially and longitudinally, so that the balloon appears helical when wrapped; anda plurality of spaced-apart emitters positioned inside the balloon.

16. The IVL catheter of claim 15, wherein the balloon comprises a plurality of pleats.

17. The IVL catheter of claim 16, wherein, when wrapped, each pleat in the plurality of pleats is wrapped against an adjacent pleat.

18. The IVL catheter of claim 17, wherein each pleat is secured to the adjacent pleat with an adhesive.

19. The IVL catheter of claim 16, wherein each pleat comprises a wave pattern with peaks and troughs and wherein adjacent pleats are longitudinally offset so that the peaks in one pleat are longitudinally aligned with the troughs in an adjacent pleat.

20. The IVL catheter of claim 19, wherein the wave pattern is a square-wave pattern or a curved-wave pattern.

21. The IVL catheter of claim 16, wherein each pleat in the plurality of pleats has a different radial dimension.

22. The IVL catheter of claim 16, wherein the balloon has a distal shoulder and wherein a part of each pleat that forms a distal shoulder of the balloon is concave.Docket No. 23812.52a 3423. The IVL catheter of claim 15, wherein the balloon is fluidly coupled to an inflation lumen formed in the catheter shaft.

24. An intravascular lithotripsy (IVL) catheter comprising:a catheter shaft having a proximal end and a distal end, the catheter shaft including an outer member and an inner member, the inner member defining a guidewire lumen; and a balloon mounted at or near the distal end of the catheter shaft, the balloon comprising:a proximal end attached to the distal end of the outer member;a distal end attached to the inner member; anda plurality of chambers and passageways formed in the balloon and helically arranged around the inner member.

25. The IVL catheter of claim 24, wherein the plurality of chambers and passageways comprise a plurality of inflation chambers and a plurality of perfusion passageways.

26. The IVL catheter of claim 25, wherein the inflation chambers and the perfusion passageways alternate around a circumference of the balloon.

27. The IVL catheter of claim 25, wherein each inflation chamber surrounds at least one lithotripsy emitter positioned on or adjacent to the inner member.

28. The IVL catheter of claim 24, wherein each inflation chamber is in fluid communication with an inflation lumen formed in the catheter shaft.

29. The IVL catheter of claim 24, wherein each perfusion passageway comprises a proximal opening and a distal opening that allow blood to perfuse through the perfusion passageway during balloon inflation.

30. The IVL catheter of claim 24, wherein the balloon includes one or more exterior channels located between adjacent chambers.

31. The IVL catheter of claim 30, wherein the one or more exterior channels are configured to facilitate blood flow around the balloon when the balloon is inflated.

32. The IVL catheter of claim 24, wherein the plurality of chambers and passageways helically spiral along a longitudinal axis of the inner member.

33. The IVL catheter of claim 32, wherein the helical arrangement of the plurality of chambers and passageways extend along substantially an entire longitudinal length of the balloon.

34. The IVL catheter of claim 24, wherein the plurality of chambers and passageways comprises two inflation chambers and two perfusion passageways.Docket No. 23812.52a 3535. The IVL catheter of claim 24, wherein the balloon is shaped so that interfaces between adjacent chambers and passageways form exterior channels.

36. The IVL catheter of claim 25, wherein the perfusion passageway are configured to provide continuous antegrade blood perfusion during intravascular lithotripsy.

37. The IVL catheter of claim 24, wherein the balloon is configured such that activation of one or more emitters therein produces circumferentially distributed acoustic energy around a target lesion.

38. The IVL catheter of claim 24, wherein the helical chamber and passageway arrangement increases bending flexibility of the balloon relative to a balloon having longitudinally aligned chambers.

39. The IVL catheter of claim 24, further comprising a plurality of lithotripsy emitters positioned inside the balloon, each emitter located within a corresponding inflation chamber.

40. The IVL catheter of claim 24, wherein at least one perfusion passageway and at least one inflation chamber extend helically with a common pitch around the inner member.

41. An intravascular lithotripsy (IVL) catheter comprising:a catheter shaft having a proximal end and a distal end, the catheter shaft including an outer member and an inner member, the inner member defining a guidewire lumen; and a balloon positioned at or near the distal end of the catheter shaft, the balloon having a proximal end attached to the outer member and a plurality of eccentric lobes formed in the balloon, each eccentric lobe extending circumferentially around only a portion of the inner member.

42. The IVL catheter of claim 41, wherein each eccentric lobe extends around between approximately 20 percent and 60 percent of a circumferential extent of the inner member.

43. The IVL catheter of claim 41, wherein adjacent eccentric lobes are circumferentially offset from one another.

44. The IVL catheter of claim 43, wherein the eccentric lobes are circumferentially offset by approximately 120 degrees relative to one another.

45. The IVL catheter of claim 41, wherein at least two of the eccentric lobes are longitudinally spaced apart along the inner member.

46. The IVL catheter of claim 41, wherein the plurality of eccentric lobes collectively extend circumferentially around the entire inner member.Docket No. 23812.52a 3647. The IVL catheter of claim 41, further comprising a plurality of lithotripsy emitters positioned inside the balloon, wherein at least one lithotripsy emitter is located within each eccentric lobe.

48. The IVL catheter of claim 47, wherein each lithotripsy emitter is mounted on or adjacent to an outer surface of the inner member.

49. The IVL catheter of claim 41, wherein the eccentric lobes define flow paths between adjacent lobes that permit blood perfusion around the balloon when the balloon is inflated.

50. The IVL catheter of claim 41, wherein circumferential offset of the eccentric lobes provides open longitudinal channels for blood perfusion during intravascular lithotripsy.

51. The IVL catheter of claim 41, wherein at least one eccentric lobe is positioned to direct acoustic energy preferentially toward an eccentric lesion.

52. The IVL catheter of claim 41, wherein the balloon comprises a compliant or semi-compliant polymer configured to expand the eccentric lobes during inflation.

53. The IVL catheter of claim 41 , wherein each eccentric lobe is a chamber that inflates independently from an adjacent eccentric lobe.

54. The IVL catheter of claim 41, wherein the eccentric lobes collectively define a non-axisymmetric balloon profile when the balloon is inflated.

55. The IVL catheter of claim 41, wherein longitudinal spacing and circumferential offset of the eccentric lobes increase bending flexibility of the balloon.

56. The IVL catheter of claim 41, wherein each eccentric lobe comprises a region of greater radial extension and a region of lesser radial extension relative to the inner member.

57. The IVL catheter of claim 41, wherein the eccentric lobes are arranged to produce multi-directional acoustic coverage of a target lesion.Docket No. 23812.52a 37

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