Patent Description:
This disclosure relates to medical catheters.

Medical catheters have been proposed for use with various medical procedures. For example, medical catheters may be used to access and treat defects in blood vessels, such as, but not limited to, treatment of calcific atherosclerotic plaque buildup within the vasculature wall of vasculature associated with cardiovascular disease. Some techniques for treating such diseases may include balloon angioplasty alone or balloon angioplasty followed by stenting of the vasculature. However, such techniques may fail to address certain types of plaque buildup and/or result in re-stenotic events.

<CIT> describes a renal RF ablation system. <CIT> describes an angioplasty balloon. <CIT> describes a catheter with helical end section for vessel ablation. <CIT> describes a shock wave balloon catheter. <CIT> describes a shockwave nerve therapy system. <CIT> describes a shock wave balloon catheter.

The invention is defined in independent claim <NUM>, with further embodiments disclosed in the dependent claims. In some aspects, the disclosure describes catheters and catheter assemblies such as intravascular catheters, that include a plurality of electrodes mounted to and forming part of the exterior of an elongated tubular body. An energy source may be configured to deliver energy intravascularly to a fluid in contact with the electrodes to induce cavitation within the fluid in the vasculature of a patient. The cavitation may be used to treat a defect in the vasculature of the patient. For example, the cavitation may produce a high-energy pressure pulse wave that, when directed at a vasculature wall, may be used to disrupt and fracture calcific atherosclerotic plaque buildup within the vasculature wall. The disruption and fracture of the plaque may allow the vasculature to be more easily expanded to achieve better blood flow through the vessel. In some examples, the use of such devices may reduce or eliminate the need for subsequent stenting of the vasculature and reduce the chance of restenosis. In some other aspects, the disclosure describes methods of using the catheters described herein, the methods are not forming part of the claimed invention. Other features, objects, and advantages of examples according to this disclosure will be apparent from the description and drawings, and from the claims.

This disclosure describes medical device assemblies, such as intravascular catheters, that include a flexible elongated member configured to be navigated through vasculature of a patient with the assistance of a delivery sheath or guidewire, to a target treatment site within the vasculature. The elongated member includes a distal portion that includes a tubular body and one or more primary electrodes carried along the tubular body that are each connected to an external energy source. The primary electrodes are configured to intravascularly deliver energy (e.g., electrical energy) to a fluid within the vessel that may cause the fluid to rapidly heat and produce a short-lived gaseous steam/plasma bubble that quickly collapses (e.g., cavitates), releasing energy in the form of a pressure pulse wave into the vessel.

The pressure pulse wave may be used to treat a defect in the vasculature of the patient at the target treatment site. In some examples, the target treatment site may be a site within the vasculature that has a defect that may be affecting blood flow through the vasculature. For example, the target treatment site may be a portion of the vasculature wall that includes a calcified lesion, e.g., calcific atherosclerotic plaque buildup. A calcified lesion can cause partial or full blockages of blood bearing vasculatures, which can result in adverse physiological effects to the patient. Such lesions may be very hard and difficult to treat using traditional methods, such as balloon angioplasty, stenting, thrombectomy, atherectomy, or other interventional procedures. The pressure pulse wave resulting from the cavitation procedure using a catheter described herein may impact the calcified lesion (or other defect at the treatment site) to fracture or disrupt at least part of the lesion. This treatment of the calcified lesion may be used in conjunction with a treatment balloon to help open-up the blood vessel of the patient, improving blood flow in the blood vessel. For example, the treatment of the calcified lesion using the catheters described herein may help restore the vasculature to a normal or at least increased flow diameter. The exemplary procedures and methods of using the device are not forming part of the claimed invention.

Various details of the catheter assemblies are discussed below with respect to reference to <FIG>. <FIG> are schematic views of an example catheter assembly <NUM>, which includes a catheter <NUM> comprising an elongated member <NUM> and hub portion <NUM>, a wire <NUM> (e.g., a guide wire), and an energy source <NUM> electrically coupled to catheter <NUM> and wire <NUM>. Elongated member <NUM> of catheter <NUM> extends from a proximal end 15A to a distal end 15B with proximal end 15A connected to hub portion <NUM>. Elongated member <NUM> includes a distal portion <NUM> comprising a tubular body <NUM> that defines an inner lumen <NUM> and includes one or more primary electrodes <NUM> positioned along tubular body <NUM>. Wire <NUM> includes at least one secondary electrode <NUM> and is slidably disposed within inner lumen <NUM>. <FIG> provide greater detail of distal portion <NUM> of catheter <NUM>, illustrating both a side view (<FIG>) and a cross-sectional side view (<FIG>) of distal portion <NUM>.

As described further below, energy source <NUM> is configured to deliver electrical energy between one or more of primary electrodes <NUM> and secondary electrode <NUM> located on wire <NUM>. The electrical energy is passed between one or more of primary electrodes <NUM> and secondary electrode <NUM> using fluid contained within a vessel of the patient as the conductive medium to induce cavitation of the fluid and deliver therapy to a calcified lesion on or within the vessel wall using a pressure pulse wave created by the cavitation of the fluid. To facilitate the electrical connection between primary electrodes <NUM> and secondary electrode <NUM> portions of primary electrodes <NUM> and secondary electrode <NUM> may be in non-direct contact with each other (e.g., separated by an electrically insulative material) but may each be exposed to the fluid contained within the vessel of patient. For example, each of primary electrodes <NUM> may include at least one exposed surface that lies in direct contact with the fluid, such as a bodily fluid (e.g., blood) or introduced fluid (e.g., saline), contained within the vasculature of the patient. The designation of a "primary" or a "secondary" electrode is used to merely differentiate one set of electrodes from another and is not intended to indicate a preference among the electrodes, limit the direction in which an electrical signal (e.g., an electrical pulse) is transmitted from one electrode to another, or designate where the cavitation initiates unless described otherwise in the examples.

In some examples, catheter <NUM> may be used to access relatively distal vasculature locations in a patient or other relatively distal tissue sites (e.g., relative to the vasculature access point). Example vasculature locations may include, for example, locations in a coronary artery, peripheral vasculature (e.g., carotid, iliac, or femoral artery, or a vein), or cerebral vasculature, or a heart valve (e.g., aortic valve, mitral valve, pulmonic valve, tricuspid valve, or the like). In some examples, elongated member <NUM> is structurally configured to be relatively flexible, pushable, and relatively kink- and buckle-resistant, so that it may resist buckling when a pushing force is applied to a relatively proximal portion of catheter <NUM> to advance elongated member <NUM> distally through vasculature, and so that it may resist kinking when traversing around a tight turn in the vasculature. Unwanted kinking and/or buckling of elongated member <NUM> may hinder a clinician's efforts to push the catheter body distally, e.g., past a turn in the vasculature.

Elongated member <NUM> may have any suitable length for accessing a target tissue site within the patient from a vasculature access point. The length may be measured along the longitudinal axis of elongated member <NUM>. The working length of elongated member <NUM> may depend on the location of the calcified lesion within vasculature. For example, if catheter <NUM> is a catheter used to access a coronary, carotid, or abdominal artery, elongated member <NUM> may have a working length of about <NUM> centimeters (cm) to about <NUM>, such as about <NUM>, although other lengths may be used. In other examples, or for other applications, the working length of elongated member <NUM> may have different lengths. In some examples, the length of distal portion <NUM> that includes primary electrodes <NUM> may have a total length of about <NUM> to about <NUM> in order to accommodate the length of calcified lesion <NUM>.

The outer diameter of elongated member <NUM> (e.g., the cross-sectional diameter of tubular body <NUM>) may be of any suitable size or dimension including, for example, between about <NUM> millimeter (mm) and about <NUM>. In some examples, catheter <NUM> may be characterized as a low-profile catheter having an outer diameter along distal portion <NUM> of about <NUM> to about <NUM>. The low-profile nature of catheter <NUM> may allow elongated member <NUM> to be navigated through particularly narrow or occlude vessels within the patient to treat calcified lesions with reduced openings.

In some examples, at least a portion of an outer surface of elongated member <NUM> may include one or more coatings, such as, but not limited to, an anti-thrombogenic coating, which may help reduce the formation of thrombi in vitro, an anti-microbial coating, and/or a lubricating coating. In some examples, the entire working length of elongated member <NUM> may be coated with the hydrophilic coating. In other examples, only a portion of the working length of elongated member <NUM> coated with the hydrophilic coating. This may provide a length of elongated member <NUM> distal to hub portion <NUM> with which the clinician may grip elongated member <NUM>, e.g., to rotate elongated member <NUM> or push elongated member <NUM> through vasculature. In some examples, the entire working length of elongated member <NUM> or portions thereof may include a lubricious outer surface, e.g., a lubricious coating. The lubricating coating may be configured to reduce static friction and/or kinetic friction between elongated member <NUM> and the interior wall of delivery catheter or the tissue of the patient as elongated member <NUM> is advanced through the vasculature.

Elongated member <NUM> may also include one or more radiopaque markers <NUM> which may help a clinician determine the positioning of elongated member <NUM> relative to relative to a target treatment site using ultrasound or other suitable technique. For example, one or more radiopaque markers <NUM> may be positioned along distal portion <NUM> such as near distal end 15B, adjacent to one or more of primary electrodes <NUM> or body apertures <NUM>, or the like. In some examples, one or more of primary electrodes <NUM> may act as radiopaque markers <NUM>.

The proximal portion of elongated member <NUM> may be received within hub portion <NUM> and can be mechanically connected to hub portion <NUM> via an adhesive, welding, or another suitable technique or combination of techniques. Hub portion <NUM> may serve as a handle for catheter <NUM> allowing the clinician to grasp catheter <NUM> at hub portion <NUM> and advance distal portion <NUM> through vasculature of a patient. In some examples, catheter <NUM> can include another structure in addition or instead of hub portion <NUM>. For example, catheter <NUM> or hub portion <NUM> may include one or more luers or other mechanisms (e.g., access ports <NUM>) for establishing connections between catheter <NUM> and other devices. Additionally, or alternatively, catheter <NUM> may include a strain relief body (not shown), which may be a part of hub portion <NUM> or may be separate from hub portion <NUM> to alleviate potential strain of kinking of elongated member <NUM> near its proximal end 15A.

Hub portion <NUM> may also include one or more access ports <NUM>. Access ports <NUM> may be used to pass various components through or around elongated member <NUM>. For example, access port <NUM> may permit the entry and advancement of wire <NUM> through inner lumen <NUM> that extends through elongated member <NUM>. In other examples, one or more of access ports <NUM> may be connected directly to elongated member <NUM> separate of hub portion <NUM>. In such examples, one or more of access ports <NUM> may be positioned distal to hub portion <NUM> but remain within the proximal portion of elongated member <NUM> that remains exterior to the patient during use.

<FIG> provide greater detail of distal portion <NUM> of elongated member <NUM>. Distal portion <NUM> includes tubular body <NUM>. Tubular body <NUM> may define one or more body apertures <NUM> that extend through the sidewall of tubular body <NUM> permitting direct access to inner lumen <NUM>. Body apertures <NUM> may expose secondary electrode <NUM> within inner lumen <NUM> to the fluid within the vessel of the patient. When in contact with a fluid within the vessel of a patient (e.g., blood or saline), body apertures <NUM> may provide an electrical pathway between primary electrodes <NUM> and secondary electrode <NUM> via the fluid. In such examples, both primary electrodes <NUM> and secondary electrode <NUM> will be exposed to the external environment of catheter <NUM> with the electrodes <NUM> and <NUM> being in fluid communication with the vessel wall of the patient. Energy source <NUM> may then be used to deliver an electrical signal (e.g., an electrical pulse) between primary and secondary electrodes <NUM> and <NUM> to induce cavitation of the fluid. The pressure pulse wave resulting from the cavitation procedure may be used to fracture or dislodge the calcified lesion present on or within the vessel wall.

In some examples, tubular body <NUM> may include one or more layers and configured to provide any desired shape and flexibility characteristics to elongated member <NUM>. For example, tubular body <NUM> may include a multi-layer construction that includes an inner liner, one or more support structures (e.g., coils, braids, or the like), a shape member, an outer jacket, or combinations thereof.

Tubular body <NUM> may be constructed using any suitable materials. In some examples, tubular body <NUM> may be composed of one or more polymeric materials such as polyamide, polyimide, polyether block amide copolymer sold under the trademark PEBAX, polyethylene terephthalate (PET), polypropylene, aliphatic, polycarbonate-based thermoplastic polyurethane (e.g., CARBOTHANE), or a polyether ether ketone (PEEK) polymer that provides the desired flexibility. The polymeric materials may be non-electrically conductive and extruded as one or more tubes that are used to form the completed body of tubular body <NUM>. If desired, a support structure or shape member may be included within tubular body <NUM> such as being disposed over or between one or more of the polymeric tubes used to form tubular body <NUM>. The support structure or shape member may be used to impart the desired strength, flexibility, or geometric qualities to tubular body <NUM> and/or elongated member <NUM>. The support structure or shape member may be formed using any suitable materials including, for example, metal or polymer-based wires used to form coils or braids, a hypotube, suitable shape memory materials such as nickel-titanium (nitinol), shape memory polymers, electro-active polymers, or the like. The support structure or shape member may be cut using a laser, electrical discharge machining (EDM), electrochemical grinding (ECG), or other suitable means to achieve a desired finished component length, apertures, and geometry. In some examples, the support structure or shape member may be arranged in a single or dual-layer configuration, and manufactured with a selected tension, compression, torque and pitch direction.

Primary electrodes <NUM> may be carried by tubular body <NUM> and may take on any suitable form. In some examples, primary electrodes <NUM> may define cylindrically shaped bodies that are secured (e.g., crimped) to tubular body <NUM>. For example, primary electrodes <NUM> may be formed using a marker band crimped over tubular body <NUM>. While primary electrodes <NUM> are primarily shown and described as being cylindrical in shape, other structures and shapes such as rings, ring or cylindrical segments, exposed segments of electrical conductors, wires, or support structures, or the like may also be used to form primary electrodes <NUM>.

Primary electrodes <NUM> may be positioned at any appropriate interval and quantity along the length of distal portion <NUM> of elongated member <NUM>. In some examples, primary electrodes <NUM> may be separated by a longitudinal distance of at least about <NUM> to about <NUM> from each other. Maintaining a separation difference of at least about <NUM> may allow primary electrodes <NUM> function independently of one another, where desired, such that the electrical signal does not pass from one primary electrode <NUM> to another.

Each of primary electrodes <NUM> may be positioned adjacent to one or more body apertures <NUM> to provide a pathway between a respective primary electrode <NUM> and wire <NUM> disposed within inner lumen <NUM>. The separation distance between primary electrode <NUM> and a respective body aperture <NUM> along the longitudinal axis may determine whether the electrical pulse is delivered as an arc or corona. In examples in which an arc discharge is desired, a respective primary electrode <NUM> and a respective body aperture <NUM> may be separated by less than about <NUM> to establish an appropriate electrical connection between the respective primary electrode <NUM> and secondary electrode <NUM> through body aperture <NUM>. In examples in which a corona discharge is desired, a respective primary electrode <NUM> and a respective body aperture <NUM> may be separated by the same distance (e.g., less than about <NUM>) or a much greater distance (e.g., separated by a distance of about <NUM> to about <NUM>). Additionally, or alternatively, body apertures <NUM> may aligned with a respective primary electrode <NUM> (e.g., the electrode configuration of <FIG>).

Primary electrodes <NUM> may be connected to energy source <NUM> via one or more electrical conductors <NUM> that extend along the length of elongated member <NUM> and electrically coupled to energy source <NUM> via one or more cables <NUM>. In the example shown in <FIG>, primary electrodes <NUM> are connected in series by conductors <NUM>. For example, conductors <NUM> may be formed using a single wire that is coupled (e.g., soldered) to each primary electrode <NUM> as the respective electrodes are coupled to tubular body <NUM>. In such examples, each of primary electrodes <NUM> may be at the same electrical potential. However, in other examples, primary electrodes <NUM> may be connected to energy source <NUM> by individually activated conductors <NUM> or by using another suitable electrical arrangement.

In some examples, electrical conductors <NUM> and primary electrodes <NUM> may be imbedded or integrally formed with tubular body <NUM> such that electrical conductors <NUM> are secured between polymeric layers that make up part of tubular body <NUM>. For example, as part of the construction of catheter <NUM>, primary electrodes <NUM>, electrical conductors <NUM>, or both may be positioned over and secured to an inner layer of tubular body <NUM> using an outer layer (e.g., an outer jacket) of flexible polymeric material. In some examples, the outer layer may be heat shrunk on to the inner layer to form an exterior of elongated member <NUM> and secure electrical conductors <NUM> and primary electrodes <NUM> in place on elongated member <NUM>. Portions of primary electrodes <NUM>, if covered by the outer layer or material may then be removed by, for example, laser etching or other suitable technique to expose at least a portion each electrode <NUM> to the external environment so the exposed surface of the electrode contacts the surrounding fluid. In some examples, primary electrodes <NUM> may comprise an exposed surface area of less than about <NUM><NUM>.

Primary electrodes <NUM>, wire <NUM>, secondary electrode <NUM>, conductors <NUM>, or any other electrical conduit described herein may be formed using any suitable electrically conductive material including, for example, titanium alloys (e.g., Ti-Mo alloy), platinum or platinum-iridium alloys, stainless steel, copper, copper alloys (e.g., copper and hafnium or tungsten), tungsten, or the like. In some examples, conductors <NUM> or wire <NUM> may be formed using electrically insulated metal wires that extend along elongated member <NUM>. The materials and design of primary electrodes <NUM>, secondary electrode <NUM>, wire <NUM>, and conductors <NUM> may be selected such that the components do not significantly impede or hinder the navigability of catheter <NUM>.

Wire <NUM> of catheter assembly <NUM> is slidably disposed within inner lumen <NUM>. In some examples, wire <NUM> may represent a guide wire such as a <NUM> inch gauge wire (e.g., about <NUM> OD). In some examples, wire <NUM> may include an electrically insulative sheath (e.g., made from paralyene, polyimide, PTFE, or the like) disposed over wire <NUM> such that only a portion of wire <NUM> is exposed to form secondary electrode <NUM>. In the example illustrated in <FIG>, the exposed portion of wire <NUM> forming secondary electrode <NUM> occurs at the distal tip of wire <NUM>, however in other examples, the exposed portion or portions of wire <NUM> may occur along other parts of wire <NUM>. In some examples, wire <NUM> may exclude the presence of an electrically insulative sheath such that the entire body of wire <NUM> functions as secondary electrode <NUM>. As described further below, the selection of the type of construction for wire <NUM> may depend on the type of cavitation procedure intended (e.g., corona-based cavitation or arc-based cavitation).

In some examples, distal portion <NUM> of elongated member <NUM> may also include an atraumatic, flexible tip <NUM> at distal end 15B of the elongated member <NUM>. Flexible tip <NUM> can be affixed to the distal end of tubular body <NUM> via adhesive, crimping, over-molding, or other suitable techniques or may be integrally formed as part of tubular body <NUM>. In some examples, flexible tip <NUM> can be made from a polymeric material (e.g., polyether block amide copolymer sold under the trademark PEBAX), a thermoplastic polyether urethane material (sold under the trademarks ELASTHANE or PELLETHANE), or other suitable materials having the desired properties, including a selected durometer.

<FIG>, and <FIG> are enlarged conceptual cross-sectional views showing example cavitation procedures that may be performed using catheter assembly <NUM> of <FIG>. <FIG> illustrate an example where cavitation is induced by individual primary electrodes <NUM>, while <FIG> illustrates an example where cavitation is induced simultaneously using multiple primary electrodes <NUM>.

<FIG> shows part of distal portion <NUM> of catheter <NUM> introduced to a target treatment site containing a calcified lesion <NUM> on or within a wall of vessel <NUM> of a patient. Wire <NUM> may be positioned within inner lumen <NUM> such that secondary electrode <NUM> is aligned with a first body aperture 30a, which is positioned adjacent to primary electrode 26a. In some examples, wire <NUM> may include visual markers along the proximal side, notches, rumble strips, radiopaque markers, or the like that help indicate the alignment of wire <NUM> relative to inner lumen <NUM>.

Wire <NUM> may be covered with an electrically insulative material (e.g., sheath) so that only the distal tip of wire <NUM> is exposed to form secondary electrode <NUM>. When secondary electrode <NUM> is aligned with first body aperture 30a, the presence of body aperture 30a will provide fluidic communication between primary electrode 26a and secondary electrode <NUM>. Fluid <NUM> contained within or introduced into the vasculature of the patient (e.g., blood, contrast solution, saline, or the like) may fill body aperture 30a such that fluid <NUM> lies in direct contact with both primary electrode 26a and secondary electrode <NUM>.

From the position shown in <FIG>, energy source <NUM> may deliver an electrical pulse in the form of a corona, arc, spark, or the like between primary electrode 26a and secondary electrode <NUM> using fluid <NUM> as the conductive medium. The electrical signal (e.g., arch or corona) causes fluid <NUM> to form gaseous steam/plasma bubbles within fluid <NUM> that form and cavitate near electrodes 26a and/or <NUM>. The steam/plasma bubbles may represent relatively low-pressure pockets of vapor sourced by the surrounding fluid <NUM>. The low-pressure steam/plasma bubbles eventually collapse in on themselves due to the relatively high pressure of the surrounding fluid <NUM> and heat loss of the steam/plasma bubbles to the surrounding fluid <NUM>. As the steam/plasma bubbles collapse, the bubbles release a large amount of energy in the form of a high-energy pressure pulse wave <NUM> within fluid <NUM>.

In some examples, the site for cavitation may be controlled by controlling the surface area and/or materials of exposed surfaces or primary and secondary electrodes <NUM> and <NUM>. For example, when applying corona based cavitation, the electrode with the smaller surface area may have a higher current density and therefore act as the site for cavitation to occur. Additionally, or alternatively, the direction of the resultant pressure pulse waves produced by the cavitation may be controlled based on the circumferential orientation of the electrode where cavitation is to occur.

The formation and subsequent collapse of the steam/plasma bubbles may be short lived or nearly instantaneous, causing the pressure pulse waves <NUM> to originate near primary electrode 26a or secondary electrode <NUM>. In some examples, the location where the steam/plasma bubbles originate may be controlled by reducing the amount of surface area exposed to fluid <NUM> on either primary electrode 26a or secondary electrode <NUM> provided for nucleation. In some examples, the steam/plasma bubbles will originate on the associated electrode 26a or <NUM> having the smallest exposed surface area. In some examples where the origination of the cavitation is desired near secondary electrode <NUM>, the amount of secondary electrode <NUM> exposed may be controlled by controlling the size and/or number of body apertures 30a associated with the respective primary electrode 26a.

Once produced, pressure pulse waves <NUM> propagate through fluid <NUM> where they impact the wall of vessel <NUM> in which distal portion <NUM> is deployed, transmitting the mechanical energy of pressure pulse wave <NUM> into the tissue of vessel <NUM> and calcified lesion <NUM> at the target treatment site. The energy transmitted to calcified lesion <NUM> may cause the calcified lesion to fracture or break apart. In some examples, the relative intensity of pressure pulse waves <NUM> may be adjusted by controlling the intensity of the electrical signal delivered between primary electrodes <NUM> and secondary electrode <NUM>. The intensity of the electrical signal may be a function of one or more of a voltage, a current, a frequency (e.g., a pulse rate in the case of pulses), a pulse width, or one or more other electrical signal parameters.

In some examples, fluid <NUM> may be introduced (e.g., perfused) into the vessel and body apertures <NUM> by the clinician. For example, elongated member <NUM> may be configured such that fluid <NUM>, e.g., saline, contrast solution, or the like, may be introduced through inner lumen <NUM> via one or more supply tubes of catheter <NUM>. In some examples, saline, as opposed to blood, may more readily undergo cavitation thereby requiring less energy to induce cavitation than blood when saline is used as fluid <NUM>, however any suitable fluid <NUM> may be introduced into the vessel and body apertures <NUM> for the cavitation procedure. Example fluids <NUM> may include, but are not limited to, biocompatible fluids such as saline or similar solution with a salt content between about <NUM> weight percent (wt. %) and about <NUM> wt. %; contrast media (e.g., about <NUM> volume percent (vol. %) to about <NUM> vol. % contrast media), blood, or the like. The higher the salt content of the saline fluid, the higher the conductance will be for the fluid, thereby requiring less energy to increase the temperature of the fluid and induce cavitation. Additionally, the higher the concentration of contrast media, the more viscous fluid <NUM> will be leading to a higher dissipation of the cavitation bubbles.

After performing cavitation using primary electrode 26a, wire <NUM> or catheter <NUM> may be retracted proximally relative to calcified lesion <NUM> until secondary electrode <NUM> aligns with a second body aperture 30b adjacent to a second primary electrode 26b (e.g., <FIG>). Energy source <NUM> may then deliver another electrical pulse which travels between primary electrode 26b and secondary electrode <NUM> to cause fluid <NUM> in contact with both primary and secondary electrodes 26b and <NUM> to undergo cavitation and produce a pressure pulse wave <NUM> as described above. Depending on the orientation (e.g., annular position around tubular body <NUM>) and size of body apertures <NUM> or the exposed surface of primary electrodes <NUM>, the resulting pressure pulse wave <NUM> may be directed to the same or different radial positions along a wall of vessel <NUM>.

The above process may be continued for additional primary electrodes <NUM> positioned along elongated member <NUM> until a desired amount of pulse wave energy has been delivered into vessel <NUM> and calcified lesion <NUM> over a desired portion of the vessel wall.

<FIG> illustrates another example cavitation procedure that may be performed using catheter <NUM>. <FIG> shows part of distal portion <NUM> of catheter <NUM> introduced to a target treatment site containing calcified lesion <NUM> on or within a wall of vessel <NUM> of the patient. Wire <NUM> may be positioned within inner lumen <NUM>, however unlike the example of <FIG>, wire <NUM> may exclude the presence of an electrically insulative sheath such that the entire body of wire <NUM> effectively functions as a secondary electrode where wire <NUM> is exposed to fluid <NUM> by body apertures 30a and 30b.

Energy source <NUM> may deliver an electrical pulse which travels between each of primary electrodes 26a and 26b and wire <NUM> (e.g., the secondary electrode) to cause fluid <NUM> in contact with both primary electrodes 26a and 26b and wire <NUM> via body apertures 30a and 30b to undergo cavitation and produce pressure pulse waves <NUM> as described above. In some examples, the electrical signal delivered between primary electrodes 26a and 26b and wire <NUM> may be characterized as a corona. The exposed surfaces of primary electrodes 26a and 26b and/or location of body apertures <NUM> may be oriented in different circumferential directions alone elongated member <NUM> to allow for <NUM>° deployment of the pressure pulse waves within the vessel.

By conducting the above cavitation procedures in vessel <NUM> of a patient within fluid <NUM> in direct and intimate contact with a wall of vessel <NUM>, the transfer of energy from pressure pulse waves <NUM> to the target calcified lesion <NUM> may be more efficient as compared to a cavitation procedure that introduces one or more intermediate devices, such as a balloon, between the source of cavitation (e.g., primary electrodes <NUM>) and calcified lesion <NUM>. Additionally, by including a plurality of primary electrodes <NUM>, a plurality of body apertures <NUM>, or both, the techniques of this disclosure may allow for the pressure pulse wave energy to be delivered over a longer longitudinal distance of vessel <NUM> without needing to reposition distal portion <NUM> within vessel <NUM> mid process.

In some examples, the more efficient transfer of energy from pressure pulse waves <NUM> to calcified lesion <NUM> may reduce the duration of which the cavitation procedure is performed or reduce the energy requirements needed to sufficiently fracture or break apart calcified lesion <NUM> resulting in an overall shorter procedure. Additionally, or alternatively, due to the improved efficiency of the cavitation process, the cross-sectional profile of catheter <NUM> may be reduced. For example, the lower power requirements may mean that the components used in the cavitation process (e.g., primary electrodes <NUM>, wire <NUM>, and the like) may require a lower energy load thereby allowing for smaller gauge of components to be incorporated into catheter <NUM>. In some examples, the lowered power demands may also permit catheter <NUM> and associate energy source <NUM> to be operated as a handheld unit.

Following completion of either of the above described cavitation processes, vessel <NUM> may be subsequently expanded (e.g., via balloon expansion) to a larger flow diameter. For instance, the clinician may position a balloon (e.g., a POBA) adjacent to the location of cavitation and expand the balloon (e.g., to about <NUM>-<NUM> atmospheres of pressure). In some examples, the cavitation process and balloon expansion sequence may be performed once or may be performed multiple times.

<FIG> is a schematic block diagram of an example energy source <NUM> that may be used with catheter assembly <NUM> of <FIG> to induce cavitation of fluid <NUM>. <FIG> shows a schematic block diagram of an example energy source <NUM> that may be used with catheter assembly <NUM> to induce cavitation within fluid <NUM>. Energy source <NUM> includes control mechanism <NUM>, memory <NUM>, processing circuitry <NUM>, electrical signal generator <NUM>, and power source <NUM>.

Processing circuitry <NUM> may include any one or more microprocessors, controllers, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), discrete logic circuitry, or any processing circuitry configured to perform the features attributed to processing circuitry <NUM>. The functions attributed to processors described herein, including processing circuitry <NUM>, may be provided by a hardware device and embodied as software, firmware, hardware, or any combination thereof. In some examples, processing circuity may include instructions to recognize a particular primary and secondary electrode <NUM> and <NUM> configuration or allow a clinician to manually input the specific primary and secondary electrode <NUM> and <NUM> configuration of catheter <NUM>. In some examples, energy source <NUM> may include additional components such as, a display device or user input device that are not expressly shown for displaying information from processing circuitry <NUM> or allowing the clinician to input information.

Memory <NUM> may include any volatile or non-volatile media, such as a random access memory (RAM), read only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, and the like. Memory <NUM> may store computer-readable instructions that, when executed by processing circuitry <NUM>, cause processing circuitry <NUM> to perform various functions described herein. Memory <NUM> may be considered, in some examples, a non-transitory computer-readable storage medium including instructions that cause one or more processors, such as, e.g., processing circuitry <NUM>, to implement one or more of the example techniques described in this disclosure. The term "non-transitory" may indicate that the storage medium is not embodied in a carrier wave or a propagated signal. However, the term "non-transitory" should not be interpreted to mean that memory <NUM> is non-movable. As one example, memory <NUM> may be removed from energy source <NUM>, and moved to another device. In certain examples, a non-transitory storage medium may store data that can, over time, change (e.g., in RAM).

Processing circuitry <NUM> is configured to control energy source <NUM> and electrical signal generator <NUM> to generate and deliver the electrical signal across one or more primary and secondary electrodes <NUM> and <NUM> to induce cavitation of fluid <NUM>. Electrical signal generator <NUM> includes electrical signal generation circuitry and is configured to generate and deliver an electrical signal in the form of and electrical pulse. In the case of electrical pulses, electrical signal generator <NUM> may be configured to generate and deliver pulses having an amplitude of about <NUM> volts (V) to about <NUM> V (e.g., between about 1500V to about <NUM> V), a pulse width of about <NUM> microsecond (µs) to about <NUM> for arc-type cavitation or about <NUM> to about <NUM> for corona-type cavitation, and a frequency of about <NUM> Hertz (Hz) to about <NUM>. In some examples, catheter <NUM> may be configured such that electrical conductors <NUM> are independently coupled to one or more primary electrodes <NUM>. In such examples, processing circuitry <NUM> may control electrical signal generator <NUM> to generate and deliver multiple electrical signals via different combinations of electrical conductors <NUM> and/or primary electrodes <NUM>. In these examples, energy source <NUM> may include a switching circuitry to switch the delivery of the electrical signal using primary electrodes <NUM>, e.g., in response to control by processing circuitry <NUM>.

Power source <NUM> delivers operating power to various components of energy source <NUM>. In some examples, power source <NUM> may represent hard-wired electrical supply of alternating or direct electrical current. In other examples, power source <NUM> may include a small rechargeable or non-rechargeable battery and a power generation circuit to produce the operating power. Recharging may be accomplished through proximal inductive interaction between an external charger and an inductive charging coil within energy source <NUM>.

A control mechanism <NUM>, such as foot pedal, handheld, or remote-control device, may be connected to energy source <NUM> to allow the clinician to initiate, terminate and, optionally, adjust various operational characteristics of energy source <NUM>, including, but not limited to, power delivery. Control mechanism <NUM> can be positioned in a sterile field and operably coupled to the energy source <NUM> and can be configured to allow the clinician to selectively activate and deactivate the energy delivered to one or more of primary and secondary electrodes <NUM> and <NUM>. In other embodiments, control mechanism <NUM> may be built into hub portion <NUM>.

<FIG> illustrate additional schematic side views of example electrode configurations that may be used with catheter assembly <NUM> or the other catheter assemblies described herein. <FIG> are schematic diagrams illustrating both a side view (<FIG>) and a cross-sectional side view (<FIG>) of an example distal portion 22A of an elongated member 14A that may be used with catheter <NUM> or the other catheters described herein. Distal portion 22A includes a tubular body 24A that defines a plurality of body apertures <NUM> that extend through a sidewall of tubular body 24A. Elongated member 14A also includes one or more primary electrodes <NUM> carried along tubular body <NUM> (e.g., carried over an electrically insulative inner layer). Primary electrodes <NUM> may be substantially similar to primary electrodes <NUM> described above, however each of primary electrodes <NUM> may further define an electrode aperture <NUM> extending through the body of the electrode. Each electrode aperture <NUM> may be substantially aligned (e.g., aligned or nearly aligned) with a respective body aperture <NUM> such that the two apertures form a single opening (e.g., the two apertures are concentric or coaxial to with one another). In this configuration, the pathway between primary electrodes <NUM> and secondary electrode <NUM> may be created directly through each of primary electrodes <NUM> with portions of tubular body 24A separating the two electrodes from being in direct contact.

In some examples, both electrode apertures <NUM> and body apertures may be formed at the same time using laser etching or other suitable technique to form the respective apertures after primary electrodes <NUM> have been added to distal portion 22A. Additionally, or alternatively, the formation of electrode apertures <NUM> may produce the exposed surface of primary electrodes <NUM> used in the cavitation procedures. For example, an outer jacket may be formed over primary electrodes <NUM> as part of the formation of tubular body 24A. The ablation process used to create electrode apertures <NUM> may simultaneously remove part of the outer jacket covering primary electrodes <NUM>, thereby exposing the surface of primary electrode <NUM> along the edge of electrode aperture <NUM>. In some examples, electrode apertures <NUM> may define an aperture diameter on between about <NUM> and about <NUM>.

In some examples, by constructing primary electrodes <NUM> with corresponding electrode apertures <NUM>, the location and orientation of the resulting pressure pulse waves <NUM> generated during a cavitation procedure may be controlled by controlling the location and direction of electrode apertures <NUM>. Furthermore, the relatively short distance between a respective primary electrode <NUM> and secondary electrode <NUM> when wire <NUM> is aligned within lumen <NUM> (e.g., less than about <NUM> such as less than about <NUM>) may help ensure that the electrical signal is delivered across only a particular set of primary and secondary electrodes to cause fluid <NUM> to cavitate.

<FIG> are schematic diagrams illustrating both a side view (<FIG>) and a cross-sectional side view (<FIG>) of another example distal portion 22B of an elongated member 14B that may be used with catheter <NUM> or the other catheters described herein. Distal portion 22B includes a tubular body 24A that defines a plurality of body apertures <NUM> that extend through a sidewall of tubular body 24A. Tubular body includes an electrically conductive support structure <NUM> such as a metallic braid, coil, hypotupe, shape member, or the like. Support structure <NUM> may provide structural support, shape memory properties, or the like to elongated member 14B as well as serve as an electrical conductor (e.g., electrical conductor <NUM> of <FIG>) for the primary electrodes. Body apertures <NUM> may pass directly through support structure <NUM> to expose portions of support structure <NUM> to the surrounding fluid <NUM> (e.g., the external environment of catheter <NUM>). The exposed portions of support structure <NUM> may be characterized as primary electrodes <NUM> and may perform substantially the same function as the exposed portions of primary electrodes <NUM> described above.

In some such examples, tubular body 24A may include an inner liner <NUM> of a non-conductive material that may be used to separate primary electrodes <NUM> from wire <NUM> and/or secondary electrode <NUM> contained within inner lumen <NUM> of tubular body 24B.

In some examples, elongated member <NUM> of catheter <NUM> may include a distal portion configured to transform from a collapsed, low-profile (e.g., linear) configuration to a deployed curvilinear configuration (e.g., helical or spiral configuration) when positioned adjacent the target treatment site. <FIG> are schematic views of a catheter assembly <NUM>, according to the claimed invention, which includes a catheter <NUM> comprising an elongated member <NUM> and a hub portion <NUM>, and an energy source <NUM> electrically coupled to catheter <NUM>. Elongated member <NUM> extends from a proximal end 94A to a distal end 94B with proximal end 94A connected to hub portion <NUM>. Elongated member <NUM> includes a distal portion <NUM> comprising a plurality of primary electrodes <NUM> positioned along tubular body <NUM>. Distal portion <NUM> is configured to transform into a curvilinear configuration (e.g., helical or spiral shaped) when deployed within vasculature of a patient. Energy source <NUM> is configured to deliver electrical energy to primary electrodes <NUM> to induce cavitation of a fluid within a vessel of the patient to deliver therapy to a calcified lesion on or within the vessel wall using a pressure pulse wave created by the cavitation of the fluid.

<FIG> provide greater detail of distal portion <NUM> of catheter <NUM>. <FIG> is a schematic perspective view of distal portion <NUM> and FIG. C is a cross-sectional side view of distal portion <NUM>. For ease of illustration and description, <FIG> is shown with distal portion <NUM> having a linear profile where elongated member <NUM> is extended linearly rather than in the curvilinear configuration as shown in <FIG> and <FIG>.

One or more aspects of catheter assembly <NUM> and catheter <NUM> may be substantially similar to the systems described above with respect to <FIG> including, for example, the configuration of the primary electrodes, parts of the tubular body, the hub portion, the body and/or electrode apertures, the cavitation processes preformed, or the like apart from any differences noted below. For simplicity, catheter <NUM> will be primarily described as having primary electrodes <NUM> configuration similar primary electrodes <NUM> described in <FIG>, however other electrode configurations and designs described herein may also be incorporated into the curvilinear construction of catheter <NUM>.

Distal portion <NUM> of elongated member <NUM> includes a tubular body <NUM> defining an inner lumen <NUM> and a plurality of body apertures <NUM> that extend through a sidewall of tubular body <NUM> into the inner lumen <NUM>. Tubular body <NUM> is configured to change from a first collapsed configuration (e.g., low-profile or generally linear configuration) to a second curvilinear configuration. The curvilinear configuration defines a spiral or helically-shaped configuration such that distal portion <NUM> of elongated member <NUM> curls (e.g., helically wraps) about a central longitudinal axis <NUM>.

In some examples, the deployed curvilinear configuration of distal portion <NUM> may be established using a shape member <NUM> comprising a shape memory metal or other material. Shape member <NUM> may be used to provide a spiral/helical-shape to the relatively flexible distal portion <NUM> of catheter <NUM>. In some examples, shape member <NUM> may be formed within or as part of tubular body <NUM>. For example, tubular body <NUM> may be composed of one or more layers of polymeric materials such as polyamide, polyimide, polyether block amide copolymer sold under the trademark PEBAX, polyethylene terephthalate (PET), polypropylene, aliphatic, polycarbonate-based thermoplastic polyurethane (e.g., CARBOTHANE), or a polyether ether ketone (PEEK) polymer that provides the desired flexibility. The polymeric materials may be extruded as one or more tubes that are used to form the completed body of tubular body <NUM>. Shape member <NUM> may be disposed over or between one or more of the polymeric tubes used to form tubular body <NUM> using suitable techniques to impart the desired geometric qualities to tubular body <NUM>.

Shape member <NUM> may be formed from suitable shape memory materials such as nickel-titanium (nitinol), shape memory polymers, electro-active polymers, or the like that are pre-formed or pre-shaped into the desired curvilinear geometry. In some examples, shape member <NUM> may include a tubular structure such as multifilar stranded wire (e.g., Helical Hollow Strand™ sold by Fort Wayne Metals of Fort Wayne, Indiana) comprising nitinol or other shape memory material. Shape member <NUM> may be cut using a laser, electrical discharge machining (EDM), electrochemical grinding (ECG), or other suitable means to achieve a desired finished component length, apertures, and geometry for creating the curvilinear configuration. In some examples, shape member <NUM> may be formed from a variety of different types of materials, arranged in a single or dual-layer configuration, and manufactured with a selected tension, compression, torque and pitch direction.

In some examples, the curvilinear configuration may be characterized by dimensions of the curved shape (e.g., the shape of the helix) that are distinct from the dimensions of tubular body <NUM> or components thereof. In some examples, the curvilinear configuration may define a diameter (e.g., helix diameter) of about <NUM> to about <NUM> and a pitch (e.g., distance along longitudinal axis <NUM> for one full rotation) of about <NUM> to about <NUM>. Additionally, or alternatively, the pitch or diameter of the curvilinear configuration may be expressed as a ratio compared to the diameter of tubular body <NUM>. In some examples, the diameter of the curvilinear configuration to the diameter of tubular body <NUM> may be about <NUM>:<NUM> to about <NUM>:<NUM> but other ratios may also be used.

As shown in <FIG> and <FIG>, in an embodiment of the claimed invention, the tubular body <NUM> is configured to exhibit pre-set spiral/helical configuration that defines the deployed state of the catheter assembly <NUM> such that plurality of primary electrodes <NUM> are offset both angularly and longitudinally from each other when in the deployed curvilinear configuration thereby allowing primary electrodes <NUM> to engage with the vessel wall of a patient at different parts and radial position of even though the relative diameter of tubular body <NUM> may be less than that of the vessel. In some examples, the curvilinear configuration may position tubular body <NUM> and primary electrodes <NUM> in intimate contact or with little or no space between the exterior surfaces of elongated member <NUM> and the interior surface of the vessel wall.

In some examples, primary electrodes <NUM> may define cylindrically shaped bodies that are positioned over and secured (e.g., crimped) to tubular body <NUM>. While primary electrodes <NUM> are primarily shown and described as being cylindrical in shape, other structures and shapes such as rings, ring or cylindrical segments, or the like may be used. Additionally, or alternatively, primary electrodes <NUM> may be formed by exposed segments of an electrical conductor, a support structure, shape member <NUM>, or the like.

Plurality of primary electrodes <NUM> are carried by tubular body <NUM> and may define a surface area exposed to fluid <NUM>. In some examples, each of primary electrodes <NUM> may define a corresponding electrode aperture <NUM> that extends through the respective electrode <NUM> (e.g., similar to electrode apertures <NUM>). Each electrode aperture <NUM> may aligned with a corresponding body aperture <NUM> of tubular body <NUM> to provide direct access (e.g., provide fluid communication) between inner lumen <NUM> and exposed surfaces of primary electrodes <NUM>.

At least a portion of each of primary electrodes <NUM> lies in direct contact with the fluid (e.g., blood or saline) in vasculature of the patient. For example, at least some of the surface of each primary electrode <NUM> adjacent to or at the edge where electrode aperture <NUM> is formed, is expose to the external environment of catheter <NUM>. In some examples, at least a portion of each primary electrode <NUM> forms an exterior surface of elongated member <NUM> and catheter <NUM>.

Primary electrodes <NUM> may be connected to energy source <NUM> via one or more electrical conductors <NUM> that extend along the length of elongated member <NUM> and electrically coupled to energy source <NUM> via one or more cables <NUM>. As described above, in some examples, electrical conductors <NUM> may connect primary electrodes in series using, for example, a single wire coupled (e.g., soldered) to each of primary electrodes <NUM>. In such examples, each of primary electrodes <NUM> may be at the same electrical potential.

In some examples, one or more of electrical conductors <NUM>, primary electrodes <NUM>, and shape member <NUM> may be integrally formed with tubular body <NUM>. For example, as part of the construction of catheter <NUM>, primary electrodes <NUM> and electrical conductors <NUM> may be positioned over and secured to shape member <NUM> using a layer (e.g., outer jacket) of flexible polymeric material. The layer may be heat shrunk onto shape member <NUM> help secure electrical conductors <NUM> and primary electrodes in place relative to the shape member <NUM>. Electrode apertures <NUM> may then be formed or opened via laser etching or other suitable technique to expose at least a portion each electrode <NUM> to the external environment. In some examples, one or more additional layers of polymeric material may be positioned between shape member <NUM> and primary electrodes <NUM> and/or conductors <NUM> or positioned under shape member <NUM> to further electrically isolate shape member <NUM> from other components of catheter assembly <NUM>.

Catheter assembly <NUM> also includes a wire <NUM> that includes a secondary electrode <NUM> that functions as the return pathway to energy source <NUM>. Wire <NUM> may be substantially similar to wire <NUM> described above. In some examples, wire <NUM> is disposed within inner lumen <NUM> and slidably transitioned to align secondary electrode <NUM> with a respective primary electrode <NUM>. As described above, wire <NUM> may include an electrically insulative sheath <NUM> (e.g., made from paralyene, polyimide, PTFE) disposed over wire <NUM> such that only a portion of wire <NUM> is exposed and forms secondary electrode <NUM>. In the example illustrated in <FIG>, the exposed portion of wire <NUM> forming secondary electrode <NUM> is indicated at the distal tip of wire <NUM>, however in other examples, the exposed portion of wire <NUM> may occur along other parts of wire <NUM> or the entire wire <NUM> may be exposed.

During use, wire <NUM> is slidably maneuvered within inner lumen <NUM> to align secondary electrode <NUM> with an electrode aperture <NUM> of a respective primary electrode <NUM>. Due to the presence of electrode aperture <NUM> and body aperture <NUM>, the respective primary electrode <NUM> and secondary electrode <NUM> will be in direct contact with the fluid contained in the vessel of the patient. Upon alignment, a relatively high voltage electrical signal may be transmitted via energy source <NUM>, between secondary electrode <NUM> and the adjacent primary electrode <NUM> to induce cavitation of the fluid in direct contact with both secondary electrode <NUM> and the adjacent primary electrode <NUM>. The cavitation of the fluid may deliver resulting pressure shock wave that propagates through the fluid and impacts the vessel wall of the patient to fracture or dislodge a calcified lesion present on or within the vessel wall.

Catheter <NUM> may also include an atraumatic, flexible tip <NUM> at distal end 94B of the elongated member <NUM>. In some examples, flexible tip <NUM> may be curved and configured to direct wire <NUM> away from the vessel wall when catheter <NUM> is in the pre-set deployed configuration. This feature may help facilitate alignment of the deployed curvilinear (e.g., helical) configuration in the vessel as it expands, while also reducing the risk of injuring the blood vessel wall when the distal tip of wire <NUM> is advanced from distal end 94B. The curvature of the tip <NUM> can be varied depending upon the particular sizing/configuration of the curvilinear configuration. For example, tip <NUM> may be curved such that it is off the pre-set spiral/helical axis (axis <NUM>) defined by shape member <NUM>. Flexible tip <NUM> can be affixed to the distal end of tubular body <NUM> via adhesive, crimping, over-molding, or other suitable techniques or may be integrally formed as part of tubular body <NUM>.

Hub portion <NUM> may be substantially similar to hub portion <NUM> described above and may include one or more luers or other mechanisms (e.g., access ports <NUM>) for establishing connections between catheter <NUM> and other devices. Access ports <NUM> may be used to pass various components through or around elongated member <NUM>. For example, access port <NUM> may permit the entry and advancement of wire <NUM> through inner lumen <NUM> that extends through elongated member <NUM>. In other examples, one or more of access ports <NUM> may be connected directly to elongated member <NUM> separate of hub portion <NUM>.

The curvilinear design of elongated member <NUM> may allow for plurality of primary electrodes <NUM> to be positioned in closer proximity (e.g., direct or near direct contact) to the vessel wall of the patient allowing for a higher concentration of energy from the pressure pulse waves to be delivered into the vessel wall due to the close proximity between the source of cavitation and the vessel wall, as opposed to other catheter designs that may otherwise position the electrodes closer to a central longitudinal axis of vessel as opposed to adjacent to the vessel walls.

Distal portion <NUM> of elongated member <NUM> may be introduced through vasculature of a patient using any suitable technique. <FIG> are an enlarged conceptual side views of distal portion <NUM> illustrating one example technique using a delivery sheath <NUM> to help guide elongated member <NUM> through vasculature of a patient to a target treatment site that contains a calcified lesion <NUM> on or within a wall of vessel <NUM>. As shown in <FIG>, elongated member <NUM> may be positioned within an inner lumen <NUM> of delivery sheath <NUM>. The body of delivery sheath <NUM> may maintain elongated member <NUM> in a collapsed configuration (e.g., low-profile or linearly extended). In some examples, delivery sheath <NUM> may be configured to maintain elongated member <NUM> in the collapsed configuration while also providing sufficiently flexibility to facilitate navigation through tortuous vasculature of a patient.

Once adjacent to the target treatment site, delivery sheath <NUM> may be withdrawn proximally from distal portion <NUM> of elongated member <NUM> to allow distal portion <NUM> to advance past distal end 130B and transition into the curvilinear configuration (e.g., <FIG>). Absent the structural constraints of delivery sheath <NUM>, distal portion <NUM> may freely transition to the deployed, curvilinear configuration such as a helical or spiral shape, where elongated member <NUM> including tubular body <NUM> and primary electrodes <NUM> are positioned in close or direct contact with vessel <NUM>. In order to retrieve catheter <NUM>, delivery sheath <NUM> may be slid distally relative to elongated member <NUM> to allow distal portion <NUM> to transition back into the low profile or collapsed configuration within lumen <NUM>. In some examples, the interior surface delivery sheath <NUM> may include lubricating coating, such as a hydrophilic coating, to help slidably advance distal portion <NUM> within inner lumen <NUM> of delivery sheath <NUM>. Example materials for constructing delivery sheath <NUM> may include, for example, polyethylene (e.g., HDPE or LDPE), polyamide, or the like.

In some examples, delivery sheath <NUM> may be included as part of catheter assembly <NUM>. For example, delivery sheath <NUM> may form part catheter <NUM> disposed over tubular body <NUM> and configured to be retracted proximally by the clinician once both elongated member <NUM> and delivery sheath <NUM> have been advanced towards the target treatment site. In some such examples, both elongated member <NUM> and delivery sheath <NUM> may be simultaneously navigated through the tortuous vasculature of the patient. In other examples, delivery sheath <NUM> may represent a delivery catheter that is initially advanced through vasculature of the patient to the target treatment site followed by introduction and advancement of distal portion <NUM> of elongated member <NUM> through inner lumen <NUM> of delivery sheath <NUM>.

In other examples, distal portion <NUM> may be navigated through vasculature of a patient using wire <NUM>. For example, wire <NUM> may include relatively stiff proximal portion and a relatively flexible distal portion. Wire <NUM> may be initially navigated through vasculature of the patient until the distal end of wire <NUM> is positioned within proximity of the target treatment site. Elongated member <NUM> may then be advanced over wire <NUM>. The relatively stiff configuration of the proximal portion of wire <NUM> may help maintain distal portion <NUM> of elongated member <NUM> in the low-profile or collapsed configuration by exerting a biasing force that overcomes force of shape member <NUM> to transition into the deployed curvilinear configuration. As distal end 94B of elongated member <NUM> approaches the distal portion of wire <NUM>, the increased flexibility of wire <NUM> may be insufficient to maintain distal portion <NUM> of elongated member <NUM> in the low profile or collapsed configuration, thereby allowing distal potion <NUM> to transition into the deployed curvilinear configuration. For example, tubular body <NUM> may comprise a shape-recovery force sufficient to overcome a straightening force provided by the distal portion of wire <NUM> to transform distal portion <NUM> of elongated member <NUM> to the curvilinear configuration when the distal end of wire <NUM> is aligned or proximal to distal end 94B of elongated member <NUM>. In order to retrieve catheter <NUM>, wire <NUM> may be slid distally relative to elongated member <NUM> to allow distal portion <NUM> to transition back into the low profile or collapsed configuration.

In some examples, primary electrodes <NUM> may be separated from one another to ensure a desired distribution or primary electrodes <NUM> along the curvilinear shape of distal portion <NUM>. For example, when the curvilinear configuration is in the shape of a helix, primary electrodes <NUM> may be positioned at set rotational intervals along the helical-shape. <FIG> are example schematic views of distal portion <NUM> viewed down central longitudinal axis <NUM> (e.g., longitudinal axis <NUM> extends into the page) showing primary electrodes <NUM> spaced at different rotational intervals along tubular body <NUM>. In some examples, the spacing of primary electrodes <NUM> may be selected such that primary electrodes <NUM> are dispersed along the helical-shape at various degrees of rotation including, but not limited to, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>° (e.g., about one revolution), or other rotation intervals when distal portion <NUM> is in the fully deployed curvilinear configuration. Such spacings may allow for an even distribution of the pressure pulse waves produced by primary electrodes <NUM> along the entire wall of vessel <NUM>. <FIG>, shows primary electrodes <NUM> spaced at approximately <NUM>° intervals along the helical-shape of elongated member <NUM> and <FIG> shows primary electrodes <NUM> spaced at approximately <NUM>° intervals along the helical-shape as two examples.

Electrode and body apertures <NUM> and <NUM> may be positioned on tubular body <NUM> to obtain a specific or random orientation when distal portion <NUM> is in the fully deployed curvilinear configuration. For example, electrode and body apertures <NUM> and <NUM> may be positioned so that apertures <NUM> and <NUM> face radially outward relative to the curvilinear shape and directed toward the inner wall of vessel <NUM> of the patient (e.g., <FIG>). In such configurations the resulting pressure pulse waves produced by electrodes <NUM> and <NUM> at electrode apertures <NUM> will be directed into the adjacent wall of vessel <NUM> to maximize the amount of energy directed into the target calcified lesion <NUM>. In other examples, electrode and body apertures <NUM> and <NUM> may be positioned such that apertures <NUM> and <NUM> face radially inward relative to the curvilinear shape and are directed towards a central axis of vessel <NUM> (e.g., directed toward central longitudinal axis <NUM> as shown in <FIG>). The configuration may cause the resulting pressure pulse waves produced by electrodes <NUM> and <NUM> to be directed toward central longitudinal axis <NUM> rather than directly into the adjacent wall of vessel <NUM>. The orientation may help distribute the resulting pressure pulse wave more evenly across the wall of vessel <NUM> by allowing the pressure pulse waves to propagate within fluid <NUM> held within vessel <NUM>. The orientation may also help reduce the amount of localized heating that occurs at the wall of vessel <NUM> by directing the point where the electrical signal passes between one of primary electrodes <NUM> and secondary electrode <NUM> away from the interior surface of vessel <NUM>.

In some examples, primary electrodes <NUM> may include one or more protrusions that extend radially outward from the body of the respective electrode <NUM> to assist in the force delivery into the adjacent wall of vessel <NUM>. <FIG> is a schematic view of an example distal portion 96A of an elongated member similar to elongated member <NUM>, viewed down longitudinal axis 106A (e.g., longitudinal axis 106A extends into the page) showing primary electrodes <NUM> spaced along tubular body 100A, with each primary electrode <NUM> including a protrusion <NUM>. Each of primary electrodes <NUM> may define a respective electrode aperture <NUM> and function substantially similar to primary electrodes <NUM> described above to cause cavitation of a fluid <NUM> in contact with primary electrodes <NUM>.

Primary electrodes <NUM> may include a cylindrical body <NUM> coupled to tubular body 100A with at least one protrusion <NUM> extending radially outward and from cylindrical body <NUM> and positioned on a radially opposite side of cylindrical body <NUM> compared to electrode aperture <NUM>. Primary electrodes <NUM> may be oriented so that when elongated member <NUM> is deployed in the curvilinear configuration (e.g., helical or spiral shape), protrusions <NUM> directly contact the interior surface of vessel <NUM> with electrode apertures <NUM> facing toward central longitudinal axis 106A. During the cavitation procedure, the pressure pulse waves produced by primary electrodes <NUM> will be directed toward longitudinal axis 106A causing a recoil effect that forces the respective primary electrode <NUM> radially outward toward the wall of vessel <NUM>. Protrusions <NUM> will increase the localized force applied to the wall of vessel <NUM> and delivered to calcified lesion <NUM> located on or within vessel <NUM>. The described configuration may help maximize the force from the pressure pulse wave delivered into the wall of vessel <NUM> while also minimizing the amount of heat or generated at the point of the electrical signal is transferred between the electrodes <NUM> and <NUM>.

<FIG> are schematic cross-sectional views showing different example types of protrusions <NUM> that may be incorporated with primary electrodes <NUM>. <FIG> illustrates a single protrusion 142A on primary electrode 140A in the form of a single triangular point projecting in a radially opposite direction of electrode aperture 144A. <FIG> each illustrate a plurality of protrusions 142B, 142C on primary electrodes 140B, 140C in the form of triangular points 142B or rod-like points 142C extending in a radially opposite direction of electrode apertures 144B and 144C. While the protrusions <NUM> are generally illustrated as either triangular or rod-like points, other geometric shapes are also envisioned and may be included on primary electrodes <NUM>.

<FIG> and is a flow diagram of an example technique of using catheter assembly <NUM> or <NUM> described above. For simplicity of description, the techniques of <FIG> are described with reference to the various aspects of catheter assembly <NUM> of <FIG>, however, such descriptions are not intended to limit the techniques descried to the particular devices of <FIG>. The techniques of <FIG> may be used with other catheters assemblies or catheters assemblies <NUM> and <NUM> of <FIG> may be used for other cavitation procedures.

The technique of <FIG> includes introducing a distal portion <NUM> of an elongated member <NUM> through vasculature of a patient adjacent to a target treatment site (<NUM>), maneuvering wire <NUM> positioned within inner lumen <NUM> of elongated member <NUM> to align secondary electrode <NUM> of wire <NUM> with a first body aperture <NUM> associated with a first primary electrode 98A of elongated member <NUM> (<NUM>), delivering an electrical signal between the first primary electrode 98A and secondary electrode <NUM> to induce cavitation of fluid <NUM> in direct contact with both electrodes 98A and <NUM> and a wall of vessel <NUM> (<NUM>), maneuvering wire <NUM> to align secondary electrode <NUM> of wire <NUM> with an second body aperture <NUM> associated with of a second primary electrode 98B of elongated member <NUM> (<NUM>), and delivering an electrical signal between the second primary electrode 98B and secondary electrode <NUM> to induce a second cavitation in fluid <NUM> in direct contact with both electrodes 98B, <NUM>, and a wall of vessel <NUM> (<NUM>).

As described above, distal portion <NUM> may include one or more of primary electrodes <NUM> positioned along tubular body <NUM>. Each of primary electrodes <NUM> may be coupled to energy source <NUM> using one or more electrical conductors <NUM> extending along tubular body <NUM> and within cable <NUM> while secondary electrode <NUM> maybe connected to energy source <NUM> using wire <NUM>.

In some examples, each primary electrode <NUM> may include a respective electrode aperture <NUM> aligned with a corresponding body aperture <NUM> of tubular body <NUM> to provide fluid communication between the exposed surfaces of primary electrodes <NUM> and secondary electrode <NUM> contained within inner lumen <NUM>. Additionally, or alternatively, primary electrodes <NUM> may be defined by a support structure <NUM> or shape member <NUM> with the primary electrodes created by portions of the structures have been exposed to form electrode and body apertures <NUM>, <NUM>. In some such examples, the support structure or shape member <NUM> may also act as the electrical conductor to couple primary electrodes <NUM> to energy source <NUM>.

Distal portion <NUM> may be advanced to the target treatment site (<NUM>) using any suitable technique. For example, as described above, distal portion <NUM> may be navigated through tortuous vasculature of a patient using the aid of delivery sheath <NUM> or using wire <NUM> as a guide wire.

In some examples, such as where distal portion <NUM> is configured to transition to a curvilinear (e.g., helical) shape, delivery sheath <NUM> may be used physically restrain/bias distal portion <NUM> in a collapsed configuration (e.g., linearly-extended configuration) until distal portion <NUM> is adjacent the target treatment site. Once adjacent the target treatment site, delivery sheath <NUM> may be withdrawn proximally relative to elongate member <NUM> allowing distal portion <NUM> to transition into the deployed, curvilinear configuration within vessel <NUM> of a patient (e.g., shown in <FIG>). In other examples, distal portion <NUM> of elongated member <NUM> may be navigated through vasculature of a patient over wire <NUM>. In some such examples, the proximal portion of wire <NUM> may be relatively stiff while the distal portion of wire <NUM> may be relatively flexible. The relatively stiff configuration of the proximal portion of wire <NUM> may help maintain distal portion <NUM> of elongated member <NUM> in the low profile or collapsed configuration by exerting a biasing force that overcomes force of tubular body <NUM> to transition to the deployed curvilinear configuration. As distal end 94B of elongated member <NUM> approaches the distal portion of wire <NUM>, the increased flexibility of wire <NUM> may be insufficient to maintain distal portion <NUM> of elongated member <NUM> in the low profile or collapsed configuration, thereby allowing distal potion <NUM> to transition into the deployed curvilinear configuration.

The technique of <FIG> also includes maneuvering wire <NUM> within inner lumen <NUM> of elongated member <NUM> to align secondary electrode <NUM> with a first body aperture <NUM> associated with a first primary electrode 98A (<NUM>) (e.g., the distal most primary electrode <NUM> and body aperture <NUM> shown in <FIG>) and delivering an electrical signal between the respective primary and secondary electrodes 98A and <NUM> to induce cavitation of fluid <NUM> in direct contact with the electrodes (<NUM>). For instance, to deliver the electrical signal, the clinician may activate control mechanism <NUM> (e.g., via a foot petal) to begin delivery of the electrical signal.

As described above, the electrical signal may rapidly heat a portion of fluid <NUM> to produce short-lived gaseous steam/plasma bubbles within fluid <NUM>. The steam/plasma bubbles may represent relatively low-pressure pockets of vapor generated from the surrounding fluid <NUM>. The low-pressure steam/plasma bubbles eventually collapse in on themselves due to the relatively high pressure of the surrounding fluid <NUM>. As steam/plasma bubbles collapse, the bubbles release a large amount of energy in the form of a high-energy pressure pulse wave <NUM> within fluid <NUM> that propagates through fluid <NUM> where they impact the wall of vessel <NUM> transmitting the mechanical energy of pressure pulse wave <NUM> into the tissue of a wall of vessel <NUM> and calcified lesion <NUM>. The energy transmitted to calcified lesion <NUM> may cause the calcified lesion to fracture or beak apart.

As described above, the electrical signal may represent a corona, an electrical arc, a spark, or the like between primary electrode <NUM> and secondary electrode <NUM> in contact with fluid <NUM>. The electrical signal may be a continuous wave signal or in the form of a plurality of pulses and may have any suitable electrical signal parameters for creating the cavitation. For example, the electrical signal may have an amplitude of about <NUM> volts (V) to about <NUM> V, a pulse width of about <NUM> to about <NUM>, and a frequency of about <NUM> Hertz (Hz) to about <NUM>.

The technique of <FIG> also includes repeating cavitation procedure by maneuvering wire <NUM> within inner lumen <NUM> of elongated member <NUM> to align secondary electrode <NUM> with a second body aperture <NUM> associated with a second primary electrode 98B (<NUM>) (e.g., the proximal most primary electrode <NUM> and body aperture <NUM> shown in <FIG>) and delivering an electrical signal between the primary and secondary electrodes 98B and <NUM> to induce cavitation of fluid <NUM> in direct contact with the electrodes (<NUM>). The cavitation procedure may be repeated for all or a select number of primary electrodes <NUM> to provide therapeutic treatment along one or more desired lengths of a wall of vessel <NUM>.

Upon completion of the cavitation procedure, distal portion <NUM> may be removed from the vessel by, for example, advancing delivery sheath <NUM> back over distal portion <NUM>. In some examples, a treatment balloon may be used after the cavitation procedure to dilate the vessel and increase the flow diameter of the vessel. The treatment balloon can be provided by a separate catheter that is introduced into to the target treatment site after the cavitation catheter (e.g., catheter <NUM>) is removed from the patient. In some examples, the treatment balloon may include a therapeutic agent such as one or more of an anti-restenotic agent, an anti-proliferative agent, an anti-inflammatory agent, or other therapeutic agent over an exterior surface of the treatment balloon to help prevent restenosis of the vessel or otherwise treat the vessel or lesion. Example therapeutic agents may include, anti-proliferative agents such as paclitaxel, paclitaxel derivatives, or limus derivatives (e.g., sirolimus, everolimus, and the like), or anti-inflammatory agents such as non-steroid or steroid anti-inflammatory agents such as -COX inhibitors or glucocorticoids.

Claim 1:
A catheter assembly (<NUM>, <NUM>) comprising:
a catheter (<NUM>, <NUM>) including a flexible elongated member (<NUM>, 14A, 14B, <NUM>) including a distal portion (<NUM>, 22A, 22B, <NUM>),
the distal portion (<NUM>, 22A, 22B, <NUM>) winding around a central longitudinal axis (<NUM>) to define a helical-shape,
the distal portion (<NUM>, 22A, 22B, <NUM>) including a tubular body (<NUM>, 24A, 24B, <NUM>, 100A) defining an inner lumen (<NUM>, <NUM>), the tubular body (<NUM>, 24A, 24B, <NUM>, 100A) defining a plurality of body apertures (<NUM>, 30a, 30b, <NUM>) that extend through a sidewall of the tubular body (<NUM>, 24A, 24B, <NUM>, 100A) into the inner lumen (<NUM>, <NUM>) and a plurality of primary electrodes (<NUM>, 26a, 26b, <NUM>, <NUM>, <NUM>, <NUM>) on the tubular body (<NUM>, 24A, 24B, <NUM>, 100A); and
a wire (<NUM>, <NUM>) including a secondary electrode (<NUM>, <NUM>), the wire (<NUM>, <NUM>) being configured to be slidably moved through the inner lumen (<NUM>, <NUM>) of the tubular body (<NUM>, 24A, 24B, <NUM>, 100A).