Patent Description:
<CIT> discloses ultrasound catheter devices and methods to provide enhanced disruption of blood vessel obstructions.

A catheter assembly according to the invention is defined in claim <NUM>. The dependent claims define preferred embodiments.

Provided herein is a catheter assembly including, in some embodiments, a sonic connector at a proximal end of a core wire, a damping mechanism around a proximal end portion of the core wire, and a heat sink connected to the damping mechanism. The sonic connector is configured to couple to an ultrasound-producing mechanism and transmit vibrational energy to the proximal end of the core wire, which core wire includes a distal end portion configured to modify intravascular lesions. The damping mechanism includes a gasket system around the proximal end portion of the core wire in a damping-mechanism bore of the catheter assembly. The damping mechanism is configured to damp the vibrational energy.

In some embodiments, the heat sink includes a first sleeve around the gasket system and a second sleeve around the first sleeve. The first sleeve is of a first material having a first thermal conductivity, and the second sleeve is of a second material having a second thermal conductivity greater than the first thermal conductivity.

In some embodiments, the second sleeve is configured as a passive heat exchanger. The heat exchanger includes a number of circumferential fins arranged along a length of the second sleeve configured to dissipate the heat from the damping mechanism. Alternatively, the heat exchanger includes a number of longitudinal fins arranged around a circumference of the second sleeve configured to dissipate the heat from the damping mechanism.

In some embodiments, the first sleeve includes a cavity formed by a circumferential groove around the first sleeve. The cavity is filled with a coolant, and the second sleeve is disposed over the cavity.

In some embodiments, the coolant is water, a glycol, a water-glycol mixture, a mineral oil, a silicone oil, or a heat-storage material.

In some embodiments, the heat sink includes a first annulus at a first end of the gasket system, a second annulus at a second, opposing end of the gasket system, and a number of longitudinal members arranged around a circumference of the gasket system.

In some embodiments, a center of the gasket system is positioned over a vibrational node of the core wire where the core wire experiences less transverse-wave-producing vibrational energy than an anti-node of the core wire, thereby reducing frictional heating.

In some embodiments, the gasket system includes a number of axially and radially compressed O-rings in the damping-mechanism bore.

In some embodiments, a polymeric sleeve is around an exposed portion of the proximal end portion of the core wire between the sonic connector and a retainer configured to retain the O-rings in the damping-mechanism bore.

In some embodiments, the polymeric sleeve is around the exposed portion of the proximal end portion of the core wire and further around the proximal end portion of the core wire in the damping mechanism.

In some embodiments, the catheter assembly further includes at least a portion of an ultrasound-producing mechanism including an ultrasound transducer.

Also provided herein is a system including, in some embodiments, a catheter assembly and an ultrasound-producing mechanism. The catheter assembly includes a sonic connector at a proximal end of a core wire, a damping mechanism around a proximal end portion of the core wire, and a heat sink connected to the damping mechanism. The sonic connector is configured to transmit vibrational energy to the proximal end of the core wire, which core wire includes a distal end portion configured to modify intravascular lesions. The damping mechanism includes a gasket system around the proximal end portion of the core wire in a damping-mechanism bore of the catheter assembly. The damping mechanism is configured to damp the vibrational energy. The ultrasound-producing mechanism includes an ultrasound generator and an ultrasound transducer.

In some embodiments, the first sleeve includes a cavity formed by a circumferential groove around the first sleeve. The cavity is filled with a coolant selected from water, a glycol, a water-glycol mixture, a mineral oil, a silicone oil, and a heat-storage material. The second sleeve is disposed over the cavity sealing the coolant in the cavity.

In some embodiments, the system further includes a console including a foot switch and the ultrasound-producing mechanism including both the ultrasound generator and the ultrasound transducer. The foot switch is configured to activate and deactivate the ultrasound-producing mechanism.

In some embodiments, the system further includes a console including a foot switch and only the ultrasound generator of the ultrasound-producing mechanism. The catheter assembly further includes the ultrasound transducer of the ultrasound-producing mechanism. The foot switch is configured to activate and deactivate the ultrasound-producing mechanism.

Also provided herein is a method for making a catheter assembly including, in some embodiments, molding a cartridge including a damping-mechanism bore in a first sleeve; disposing a second sleeve over the first sleeve to form a heat sink including the first and second sleeves; disposing a core wire through a center of the damping-mechanism bore coincident with a rotational axis of the cartridge; disposing a number of O-rings in the damping-mechanism bore around the core wire; and fixing a retainer in a proximal end of the damping-mechanism bore to form a damping mechanism around the core wire. Fixing the retainer in the proximal end of the damping-mechanism bore generates a compressive force on the core wire. The compressive force is sufficient for damping vibrational energy in a proximal end portion of the core wire.

In some embodiments, the method further includes disposing the core wire in a polymeric sleeve; and uniformly heating the polymeric sleeve to shrink the polymeric sleeve around the core wire before disposing the core wire through the center of the damping-mechanism bore.

In some embodiments, the method further includes molding a housing of a catheter assembly; disposing the cartridge with the damping mechanism and the heat sink in the housing of the catheter assembly; and connecting a proximal end of the core wire to an ultrasound-producing mechanism.

Before some particular embodiments are provided in greater detail, it should be understood that the particular embodiments provided herein do not limit the scope of the concepts provided herein. It should also be understood that a particular embodiment provided herein can have features that can be readily separated from the particular embodiment and optionally combined with or substituted for features of any of a number of other embodiments provided herein.

Labels such as "left," "right," "front," "back," "top," "bottom," "forward," "reverse," "clockwise," "counter clockwise," "up," "down," or other similar terms such as "upper," "lower," "aft," "fore," "vertical," "horizontal," "proximal," "distal," and the like are used for convenience and are not intended to imply, for example, any particular fixed location, orientation, or direction.

With respect to "proximal," a "proximal portion" or a "proximal end portion" of, for example, a catheter provided herein includes a portion of the catheter intended to be near a clinician when the catheter is used on a patient. Likewise, a "proximal length" of, for example, the catheter includes a length of the catheter intended to be near the clinician when the catheter is used on the patient. A "proximal end" of, for example, the catheter includes an end of the catheter intended to be near the clinician when the catheter is used on the patient. The proximal portion, the proximal end portion, or the proximal length of the catheter can include the proximal end of the catheter; however, the proximal portion, the proximal end portion, or the proximal length of the catheter need not include the proximal end of the catheter. That is, unless context suggests otherwise, the proximal portion, the proximal end portion, or the proximal length of the catheter is not a terminal portion or terminal length of the catheter.

With respect to "distal," a "distal portion" or a "distal end portion" of, for example, a catheter provided herein includes a portion of the catheter intended to be near or in a patient when the catheter is used on the patient. Likewise, a "distal length" of, for example, the catheter includes a length of the catheter intended to be near or in the patient when the catheter is used on the patient. A "distal end" of, for example, the catheter includes an end of the catheter intended to be near or in the patient when the catheter is used on the patient. The distal portion, the distal end portion, or the distal length of the catheter can include the distal end of the catheter; however, the distal portion, the distal end portion, or the distal length of the catheter need not include the distal end of the catheter. That is, unless context suggests otherwise, the distal portion, the distal end portion, or the distal length of the catheter is not a terminal portion or terminal length of the catheter.

The term "heat capacity" is used in association with a feature (e.g., the second sleeve <NUM>) or a combination of features (e.g., the first heat sink <NUM>) and its ability or resistance to change temperature from applied heat, which is an extrinsic physical property depending upon at least a size of the feature or the combination of features.

The term "specific heat capacity" is used in association with a material (e.g., the second material of the second sleeve <NUM>) and its ability or resistance to change temperature from applied heat, which is an intrinsic physical property when the amount of the material is taken into consideration.

Atherosclerosis is characterized by one or more intravascular lesions formed, in part, of plaque including blood-borne substances such as fat, cholesterol, or calcium. An intravascular lesion such as an arterial lesion can form on a wall of an arterial lumen and build out across the lumen to an opposite arterial wall. A last point of patency often occurs at a boundary between the arterial lesion and the opposite arterial wall. Surgical procedures for atherosclerosis such as atherectomy can be used to restore patency and blood flow impeded by such lesions. However, prolonged running times required of endoluminal devices such as catheters for modification of intravascular lesions can lead to heat-related complications for the endoluminal devices, which, in turn, can lead to complications in the surgical procedures and the patients undergoing the surgical procedures. Provided herein in some embodiments are heat sinks for catheters, as well as systems and methods thereof that address at least the foregoing.

<FIG> provides a schematic illustrating a system <NUM> in accordance with some embodiments. The system <NUM> includes a console <NUM> coupled to a catheter assembly <NUM>, which system <NUM> is configured for modifying intravascular lesions including crossing the intravascular lesions, ablating the intravascular lesions, or a combination of crossing and ablating the intravascular lesions.

As shown in <FIG>, the system <NUM> includes the console <NUM>. The console <NUM> provides to the system operator an instrument for monitoring and controlling the system <NUM> and various sub-systems and functions of the system <NUM>. The console <NUM> includes an ultrasound-producing mechanism including an ultrasound generator <NUM> and an ultrasound transducer <NUM>. Alternatively, the console <NUM> includes the ultrasound generator <NUM>, the catheter assembly <NUM> includes the ultrasound transducer <NUM>, and the ultrasound-producing mechanism is divided between the console <NUM> and the catheter assembly <NUM>. The ultrasound-producing mechanism is configured to convert an electric current into vibrational energy. For example, the ultrasound generator <NUM> is configured to convert an alternating electric current (e.g., a current associated with mains electricity) into a high-frequency current (e.g., a current with a frequency commensurate with the operating frequency of the ultrasound transducer <NUM>), and the ultrasound transducer <NUM>, in turn, is configured to convert the high-frequency current into the vibrational energy (e.g., > <NUM> such as <NUM> ± <NUM>).

The console <NUM> optionally further includes a foot switch <NUM> configured to activate and deactivate the system <NUM> such as activate and deactivate at least the ultrasound-producing mechanism and any components thereof or any components coupled thereto. When the system <NUM> is powered, the foot switch <NUM> is used to activate or deactivate the system <NUM>, thereby activating or deactivating components of the ultrasound-producing mechanism such as the ultrasound transducer <NUM>; components coupled to the ultrasound-producing mechanism, such as a core wire <NUM> and a tip or tip member <NUM> of the core wire <NUM> (see <FIG> and <FIG>); or combinations thereof.

The console <NUM> optionally further includes an injector <NUM> configured to inject an irrigant into an irrigation port <NUM> of the catheter assembly <NUM>. The irrigant includes, for example, a sterile liquid (e.g., water, saline, heparinized saline, etc.) for irrigating an anatomical area undergoing an intravascular-lesion-modifying procedure (e.g., crossing an intravascular lesion, ablating an intravascular lesion, etc.), for cooling the core wire <NUM> of the catheter assembly <NUM>, or a combination thereof.

The console <NUM> optionally further includes both the foot switch <NUM> and the injector <NUM>. In such embodiments, the foot switch <NUM> can be further configured to activate and deactivate the injector <NUM> when the system <NUM> is respectively activated and deactivated with the foot switch <NUM>.

<FIG> provides a schematic illustrating the catheter assembly <NUM> in accordance with some embodiments. The catheter assembly <NUM> includes a housing <NUM> coupled to a catheter body <NUM> (see <FIG>) including a sheath <NUM>, the core wire <NUM> (see <FIG> and <FIG>) disposed in a lumen of the sheath <NUM>, and the tip or tip member <NUM>, which catheter assembly <NUM> is configured for modifying intravascular lesions including crossing the intravascular lesions, ablating the intravascular lesions, or a combination of crossing and ablating the intravascular lesions.

As shown in <FIG>, the housing <NUM> includes a hub <NUM> and a lock collar <NUM> for locking the housing <NUM> onto the ultrasound transducer <NUM>. (The irrigation port <NUM> is not shown in <FIG>, as the irrigation port <NUM> is optional in some embodiments. ) Locking the housing <NUM> onto the ultrasound transducer <NUM> ensures a proximal end of the core wire <NUM> is sufficiently vibrationally coupled to the ultrasound transducer <NUM> for modifying intravascular lesions. The proximal end of the core wire <NUM> is vibrationally coupled to the ultrasound transducer <NUM> by a sonic connector <NUM> (see <FIG> and <FIG>), optionally through an intervening ultrasound horn, and a distal end of the core wire <NUM> is vibrationally coupled to a lesion-modifying tip <NUM> fashioned from the distal end of the core wire <NUM> or a lesion-modifying tip member <NUM> coupled to the distal end of the core wire <NUM>. As such, the sonic connector <NUM> is configured to impart or otherwise transfer the vibrational energy from the ultrasound transducer <NUM> to the core wire <NUM>. And the core wire <NUM> is configured to impart or otherwise transfer the vibrational energy to the tip or tip member <NUM> of the core wire <NUM> for modifying intravascular lesions. Again, the catheter assembly <NUM> alternatively includes the ultrasound transducer <NUM>, which divides the ultrasound-producing mechanism between the console <NUM> and the catheter assembly <NUM>. In such embodiments, the housing <NUM> further includes the ultrasound transducer <NUM> disposed therein at the proximal end of the core wire <NUM>, thereby obviating the lock collar <NUM> shown in <FIG>.

A working length of a distal end portion of the core wire <NUM> beyond the sheath <NUM> or the lumen of the sheath <NUM> is configured to displace for intravascular lesion modification. The displacement includes at least longitudinal, transverse, or longitudinal and transverse displacement in accordance with a profile of the core wire <NUM> and the vibrational energy (e.g., > <NUM> such as <NUM> ± <NUM>). Longitudinal displacement of the working length of the core wire <NUM> results in micromotion such as cavitation, and transverse displacement of the working length of the core wire <NUM> results in macromotion. The micromotion is used to cross intravascular lesions. The macromotion coupled with the micromotion is used to ablate intravascular lesions, thereby breaking the lesions into minute fragments and restoring patency and blood flow.

<FIG> provides a schematic illustrating an oblique view of a cartridge <NUM> including a damping mechanism <NUM> in accordance with some embodiments. <FIG> provides a schematic illustrating a cross-sectional view of the cartridge <NUM> including the damping mechanism <NUM> of <FIG>. The damping mechanism <NUM> includes a gasket system <NUM> configured to exert a compressive force around a proximal end portion of the core wire <NUM> and a retainer <NUM> configured to retain the gasket system <NUM> within a damping-mechanism bore <NUM> of the cartridge <NUM> of the catheter assembly <NUM>.

As shown in <FIG> and <FIG>, the gasket system <NUM> includes a number of O-rings, which range from <NUM> O-ring to <NUM> O-rings, including <NUM> to <NUM> O-rings, such as <NUM> to <NUM> O-rings, for example, <NUM> to <NUM> O-rings. In some embodiments, for example, the number of O-rings is <NUM>, <NUM>, <NUM>, or <NUM> O-rings. The O-rings are axially compressed and retained in the damping-mechanism bore <NUM> by the retainer <NUM> (e.g., a washer such as a retaining washer, for example, an external star washer). Axial compression of the O-rings by the retainer <NUM> generates a radial compression by an inner wall of the damping-mechanism bore <NUM> on the core wire <NUM> sufficient to damp a number of degrees of freedom of vibrational energy provided by the ultrasound-producing mechanism not needed for modifying intravascular lesions. For example, transverse-wave-producing vibrational energy about the proximal end portion of the core wire <NUM> can be damped in favor of the longitudinal-wave-producing vibrational energy.

In embodiments of the system <NUM> including the injector <NUM>, the gasket system <NUM> prevents irrigation backflow of the irrigant through the catheter assembly <NUM> such as through the damping mechanism <NUM> and into the ultrasound transducer <NUM> of the ultrasound-producing mechanism.

The damping mechanism <NUM> further includes a sleeve <NUM> around the core wire <NUM>. The sleeve <NUM> is around at least the proximal end portion of the core wire <NUM> between the sonic connector <NUM> and the retainer <NUM>. If not encased by the sleeve <NUM>, the core wire <NUM> would include an exposed portion of the proximal end portion of the core wire <NUM> between the sonic connector <NUM> and the retainer <NUM>. The sleeve <NUM> around the proximal end portion of the core wire <NUM> between the sonic connector <NUM> and the retainer <NUM> prevents fatigue of the core wire <NUM>. The sleeve <NUM> can be further around at least the proximal end portion of the core wire <NUM> within the damping mechanism <NUM>, as well as around the core wire <NUM> distal to the damping mechanism <NUM> up to at least a length of the core wire <NUM> at which the working length of the core wire <NUM> begins.

The sleeve <NUM> around the core wire <NUM> encases the core wire <NUM> with an engineering fit selected from a clearance fit, a transition fit, and an interference fit. The clearance fit is a fairly loose fit that enables the core wire <NUM> to freely rotate or slide within the sleeve <NUM>; the transition fit firmly holds the core wire <NUM> in place within the sleeve <NUM>, but not so firmly that the core wire <NUM> cannot be removed from the sleeve <NUM>; and the interference fit securely holds the core wire <NUM> in place within the sleeve <NUM> such that the core wire <NUM> cannot be removed from the sleeve <NUM> without damaging the core wire <NUM>, the sleeve <NUM>, or both. In some embodiments, the sleeve <NUM> encases the core wire <NUM> with a transition fit or an interference fit. The transition fit and the interference fit are created by, for example, heat-shrinking a suitably sized sleeve for the desired fit about the core wire <NUM> during assembly of the catheter assembly <NUM>. The sleeve <NUM> around the core wire <NUM> is a polymeric sleeve such as a polytetrafluoroethylene ("PTFE") sleeve.

Heat in the damping mechanism <NUM> of an activated catheter assembly can build up quickly, particularly in disposable or single-use disposable catheter assemblies such as the catheter assembly <NUM> in some embodiments. Such disposable catheter assemblies cannot use typical heat exchange systems such as pipes, pumps, fans, or combinations thereof. In addition, temperature-measuring devices for the damping mechanism <NUM> such as thermocouples, on-board microprocessors, or printed circuit boards are cost prohibitive. The damping mechanism <NUM> can be centered over a vibrational node of the core wire <NUM>, or the core wire <NUM> can be adjusted such that the damping mechanism <NUM> is over a vibrational node of the core wire <NUM>. This reduces some heat caused by damping the vibrational energy because the core wire experiences less transverse-wave-producing vibrational energy at the vibrational node of the core wire than at an anti-node of the core wire. However, heat sinks for catheter assemblies such as the heat sinks provided herein are more effective than centering alone at reducing the heat, reducing the temperature in activated catheter assemblies by at least about <NUM> degrees Celsius (<NUM> degrees Fahrenheit).

<FIG> provides a schematic illustrating a cross-sectional view of the damping mechanism <NUM> and a first heat sink <NUM> in accordance with some embodiments. The heat sink <NUM> includes a first sleeve <NUM> around the gasket system <NUM> and a second sleeve <NUM> around the first sleeve <NUM>.

The first sleeve <NUM> is of a first material having a first thermal conductivity, and the second sleeve <NUM> is of a second material having a second thermal conductivity greater than the first thermal conductivity. The first material of the first sleeve <NUM> can be a polymer such as polycarbonate, and the second material of the second sleeve <NUM> can be a different polymer (e.g., polyetherimide ["PEI"]), a metal (e.g., stainless steel), or an alloy. A radially oriented thermal gradient, or a thermal gradient vector field, is thereby established from the gasket system <NUM>, through the first sleeve <NUM>, through the second sleeve <NUM>, and into a fluid medium (e.g., air within the housing <NUM>) for conducting heat away from the damping mechanism <NUM>. The thermal conductivity and thermal capacity of the heat sink <NUM> is such that the catheter assembly <NUM> can be operated for at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> minutes for modifying intravascular lesions.

<FIG> provides a schematic illustrating a cross-sectional view of the damping mechanism <NUM> and a second heat sink 510A in accordance with some embodiments. <FIG> provides a schematic illustrating a cross-sectional view of the damping mechanism <NUM> and a third heat sink 510B in accordance with some embodiments. The heat sink 510A includes a first sleeve <NUM> around the gasket system <NUM> and a second sleeve 514A around the first sleeve <NUM>. Likewise, the heat sink 510B includes the first sleeve <NUM> around 2the gasket system <NUM> and a second sleeve 514B around the first sleeve <NUM>.

As shown in <FIG> and <FIG>, the second sleeve 514A of the heat sink 510A and the second sleeve 514B of the heat sink 510B are configured as passive heat exchangers. The second sleeve 514A is configured as a passive heat exchanger with a number of circumferential fins arranged along a length of the second sleeve 514A configured to dissipate heat from the damping mechanism <NUM>. The second sleeve 514B is configured as a passive heat exchanger with a number of longitudinal fins arranged around a circumference of the second sleeve 514B configured to dissipate heat from the damping mechanism <NUM>. The second sleeve 514A and the second sleeve 514B represent just two passive heat exchangers with a number of fins configured to dissipate heat from the damping mechanism <NUM>. Instead of the circumferential fins of the second sleeve 514A or the longitudinal fins of the second sleeve 514B, the fins can be, for example, diagonal or helical, crosshatched, or segmented to form pins or more substantial protrusions.

The first sleeve <NUM> is of a first material having a first thermal conductivity, and the second sleeve 514A or the second sleeve 514B is of a second material having a second thermal conductivity greater than the first thermal conductivity. The first material also has a first specific heat capacity, and the second material also has a second specific heat capacity, which can be greater or less than the first specific heat capacity. The first material of the first sleeve <NUM> can be a polymer such as polycarbonate, and the second material of the second sleeve 514A or the second sleeve 514B can be a different polymer (e.g., PEI), a metal (e.g., stainless steel, aluminum), or an alloy (e.g., aluminum alloy). A radially oriented thermal gradient, or a thermal gradient vector field, is thereby established from the gasket system <NUM>, through the first sleeve <NUM>, through the second sleeve 514A or the second sleeve 514B, and into a fluid medium (e.g., air within the housing <NUM>) for conducting heat away from the damping mechanism <NUM>.

The thermal conductivity and heat capacity of the heat sink 510A or 510B along with a number of fins, dimensions of the fins, pitch of the fins, or the like of the heat exchanger is sufficient for operating the catheter assembly <NUM> for at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> minutes for modifying intravascular lesions. Because there can be little convection inside the housing <NUM> of the catheter assembly <NUM>, the fins of the heat sink 510A or 510B are sized as large as needed to achieve a desired operation time for the catheter assembly <NUM> while maintaining ease of use for an operator of the catheter assembly <NUM>.

<FIG> provides a schematic illustrating a cross-sectional view of the damping mechanism <NUM> and a fourth heat sink <NUM> in accordance with some embodiments and in accordance with the present claimed invention. The heat sink <NUM> includes a first annulus <NUM> at a first end (e.g., proximal end) of the gasket system <NUM>, a second annulus <NUM> at a second, opposing end (e.g., distal end) of the gasket system <NUM>. The heat sink <NUM> further includes a number of longitudinal members <NUM> set in the annuli <NUM> and <NUM> around a circumference of the gasket system <NUM> configured to conduct and dissipate heat from the damping mechanism <NUM>. Optionally, the heat sink <NUM> further includes a number of struts <NUM> set in the annuli <NUM> and <NUM> radially outward from the number of longitudinal members <NUM> for additional structural integrity.

The annuli <NUM> and <NUM> are of a first material having a first thermal conductivity, and the longitudinal members <NUM> are of a second material having a second thermal conductivity greater than the first thermal conductivity. The first material also has a first specific heat capacity, and the second material also has a second specific heat capacity, which can be greater or less than the first specific heat capacity. The first material of the annuli <NUM> and <NUM> can be a polymer such as polycarbonate, and the second material of the longitudinal members <NUM> can be a different polymer (e.g., PEI), a metal (e.g., stainless steel, aluminum), or an alloy (e.g., aluminum alloy). The thermal conductivity and heat capacity of the heat sink <NUM> is such that the catheter assembly <NUM> can be operated for at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> minutes for modifying intravascular lesions.

The number of struts <NUM> such as <NUM>, <NUM>, or <NUM> struts, when present, is sufficient to provide structural integrity without interfering with the efficiency of the longitudinal members <NUM> in dissipating heat from the damping mechanism <NUM>.

<FIG> provides a schematic illustrating a cross-sectional view of the damping mechanism <NUM> and a fifth heat sink <NUM> in accordance with some embodiments. The heat sink <NUM> includes a first sleeve <NUM> around the gasket system <NUM> and a second sleeve <NUM> around the first sleeve <NUM>. The first sleeve <NUM> includes a fillable cavity <NUM> formed by a circumferential groove around the first sleeve <NUM>.

The cavity <NUM> can simply be filled with air. Alternatively, the cavity <NUM> can be filled, in whole or in part, with a coolant of one or more materials featuring a different specific heat capacity, a different thermal conductivity, or a different specific heat capacity and a different thermal conductivity than air. For example, the coolant can be selected from water, a glycol (e.g., ethylene glycol, diethylene glycol, propylene glycol, etc.), a water-glycol mixture, a mineral oil, a silicone oil, a heat-storage material, and combinations thereof. The heat-storage material can be PX-<NUM> by Rubitherm Technologies GmbH of Berlin, Germany, which includes a phase change material on a solid support (e.g., silica). Heat from the damping mechanism <NUM> is conducted to the cavity <NUM> in accordance with a radially oriented thermal gradient and absorbed by the coolant in accordance with its specific heat capacity. With respect to the phase change material, heat from the damping mechanism <NUM> is absorbed by the phase change material to melt the phase change material instead of increasing the temperature of the heat-storage material. A benefit of the heat-storage material is that it does not melt but rather congeals as a result of the phase change material's attachment to the solid support. This makes the heat-storage material easier to contain in the cavity <NUM>. The second sleeve <NUM> around the first sleeve <NUM> provides a seal for the cavity <NUM> and any contents disposed in the cavity <NUM>.

The first sleeve <NUM> is of a first material having a first thermal conductivity, and the second sleeve <NUM> is of a second material optionally having a second thermal conductivity greater than the first thermal conductivity. The first material also has a first specific heat capacity, and the second material also has a second specific heat capacity, which can be greater or less than the first specific heat capacity. The first material of the first sleeve <NUM> can be a polymer such as polycarbonate, and the second material of the second sleeve <NUM> can be a same polymer or a different polymer (e.g., PEI), a metal (e.g., stainless steel, aluminum), or an alloy (e.g., aluminum alloy). A radially oriented thermal gradient, or a thermal gradient vector field, can be established from the gasket system <NUM>, through the first sleeve <NUM>, through the cavity <NUM> including any coolants, through the second sleeve <NUM>, and into a fluid medium (e.g., air within the housing <NUM>) for conducting heat away from the damping mechanism <NUM>. The thermal conductivity and heat capacity of the heat sink <NUM> is such that the catheter assembly <NUM> can be operated for at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> minutes for modifying intravascular lesions.

<FIG> provides a schematic illustrating a cross-sectional view of the damping mechanism <NUM> and a sixth heat sink <NUM> in accordance with some embodiments. The heat sink <NUM> is an example of a heat sink incorporating a number of features of the heat sinks 510A, <NUM>, and <NUM>. As such, the heat sink <NUM> includes a first sleeve <NUM> around the gasket system <NUM> and a second sleeve <NUM> fashioned as a passive heat exchanger around the first sleeve <NUM>. The first sleeve <NUM> includes a fillable cavity <NUM> formed by a circumferential groove around the first sleeve <NUM>, which can be filled with any coolant set forth herein, and for which the second sleeve <NUM> provides a seal. In addition, the heat sink <NUM> includes a number of longitudinal members <NUM> set in ends of the first sleeve <NUM> around a circumference of the gasket system <NUM>. The longitudinal members <NUM> are configured to extend from the heat sink <NUM> toward the proximal end of the core wire <NUM> to draw heat away from the heat sink <NUM>. The longitudinal members <NUM> are also configured to embed in any coolant in the cavity <NUM>. When the coolant is a heat-storage material, the longitudinal members are configured to draw heat away from the heat-storage material such as latent heat when the heat-storage material is in its congealed state, thereby providing stable responses for heat spikes and drawing even more heat away from the damping mechanism <NUM> when the catheter assembly <NUM> is deactivated during intermittent breaks in an intravascular-lesion-modifying procedure. Such features, as set forth herein, configure the heat sink <NUM> to conduct and dissipate heat from the damping mechanism <NUM>. The thermal conductivity and heat capacity of the heat sink <NUM> is such that the catheter assembly <NUM> can be operated for at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> minutes for modifying intravascular lesions.

Any heat sink of the heat sinks <NUM>, 510A, 510B, <NUM>, <NUM>, and <NUM> can be modified in any of a number of ways to increase or decrease operation times for the catheter assembly <NUM> including the heat sink. This is to balance manufacturing costs with expected procedure times for the catheter assembly <NUM>, which catheter assembly <NUM> is also a disposable or single-use disposable catheter assembly <NUM> in some embodiments. Not only can a heat sink of the heat sinks <NUM>, 510A, 510B, <NUM>, <NUM>, and <NUM> be modified with features of any other heat sink of the heat sinks <NUM>, 510A, 510B, <NUM>, <NUM>, and <NUM>, but materials and dimensions (e.g., relative dimensions) of the heat sink can be modified as well. For example, while the second sleeve <NUM> of the first heat sink <NUM> is shown in <FIG> as having a same thickness as the first sleeve <NUM>, the second sleeve <NUM> can be at least <NUM>, <NUM>, <NUM>, or <NUM> times thicker in some embodiments to increase the heat capacity of the second sleeve <NUM> and the heat sink <NUM>. An increase in the heat capacity of the second sleeve <NUM> can alternatively or additionally be accomplished by using a material with a higher specific heat capacity than the example materials given for the second material of the second sleeve <NUM>. For another example, while the cavity <NUM> is shown as having about half a cross-sectional area, or thickness, of the damping-mechanism bore <NUM>, the cavity <NUM> can be at least as thick as the damping-mechanism bore <NUM> or <NUM>, <NUM>, <NUM>, or <NUM> times thicker than the damping-mechanism bore <NUM> in some embodiments to increase the heat capacity of the cavity <NUM> and the heat sink <NUM>. An increase in the heat capacity of the cavity <NUM> can alternatively or additionally be accomplished by using a coolant with a higher specific heat capacity than the example coolants given for the cavity <NUM>. In general for all heat sinks provided herein, it is desired to keep a temperature below about <NUM> degrees Celsius (<NUM> degrees Fahrenheit) in the housing <NUM> of the catheter assembly <NUM> such as between the damping mechanism <NUM> and the housing <NUM>.

Making the catheter assembly <NUM> including the sonic connector <NUM> at the proximal end of the core wire <NUM>, the damping mechanism <NUM> around the proximal end portion of the core wire <NUM>, and any heat sink of the heat sinks <NUM>, 510A, 510B, <NUM>, and <NUM> includes molding a cartridge <NUM> including a damping-mechanism bore <NUM> in a first sleeve such as the first sleeve <NUM>, <NUM>, <NUM>, or <NUM>; disposing a second sleeve such as the second sleeve <NUM>, 512A, 512B, <NUM>, or <NUM> over the first sleeve to form the heat sink including the first and second sleeves; disposing the core wire <NUM> through a center of the damping-mechanism bore <NUM> coincident with a rotational axis of the cartridge <NUM>; disposing the number of O-rings in the damping-mechanism bore <NUM> around the core wire <NUM>; and fixing the retainer <NUM> in a proximal end of the damping-mechanism bore <NUM> to form the damping mechanism <NUM> around the core wire <NUM>. For the heat sink <NUM>, the steps of molding the cartridge <NUM> with the first sleeve and disposing the second sleeve over the first sleeve are modified such that molding the cartridge <NUM> includes molding the cartridge <NUM> including the second annulus <NUM>; molding the first annulus <NUM>; and disposing or otherwise setting at least the number of longitudinal members <NUM> in the annuli <NUM> and <NUM> to form the damping-mechanism bore <NUM>, or an analog thereof, and the heat sink <NUM>.

Molding the cartridge <NUM> includes molding the cartridge <NUM> by way of compression molding, injection molding, thermoforming, or a combination thereof.

Prior to disposing the core wire <NUM> through the center of the damping-mechanism bore <NUM>, the core wire <NUM> is optionally disposed in a heat-shrinkable polymeric sleeve (e.g., polytetrafluoroethylene ["PTFE"]) and uniformly heated to shrink the heat-shrinkable polymeric sleeve around the core wire <NUM> to form the polymeric sleeve <NUM> around the core wire <NUM>.

Fixing the retainer <NUM> in the proximal end of the damping-mechanism bore <NUM> generates a radial compressive force on the core wire <NUM>. The radial compressive force occurs from an axial compressive force on the O-rings resulting from axially pressing the O-rings against a distal end of the damping-mechanism bore <NUM> with the retainer <NUM> in the proximal end of the damping-mechanism bore <NUM>. The axial compressive force, in turn, generates the radial compressive force on the core wire <NUM> via radial expansion of the O-rings, thereby, radially pressing the O-rings against an inner wall of the damping-mechanism bore <NUM> opposing the core wire <NUM> and the core wire <NUM> itself. The compressive force is sufficient for damping a number of degrees of freedom of vibrational energy in the proximal end portion of the core wire <NUM>. Heat from the damping dissipates through the heat sink.

Making the catheter assembly <NUM> includes molding a housing of the catheter assembly <NUM>, and subsequently disposing the cartridge <NUM> including the damping mechanism <NUM> around the core wire <NUM> in the housing to form the catheter assembly <NUM>. Disposing the cartridge <NUM> in the housing includes connecting the sonic connector <NUM> of the core wire <NUM> to the ultrasound-producing mechanism configured to impart the vibrational energy to the proximal end of the core wire <NUM>.

Advantages of some embodiments of the catheter assembly <NUM> include, but are not limited to, passive control of heat caused by damping vibrational energy; running times sufficient for modifying intravascular lesions either by crossing, ablating, or a combination of crossing and ablating the intravascular lesions; use of polymers (e.g., polycarbonate) suitable for use in molding such as injection molding; or a combination thereof. Such advantages make possible single-use disposable catheter assemblies such as some embodiments of the catheter assembly <NUM>.

Claim 1:
A catheter assembly (<NUM>), comprising:
a sonic connector (<NUM>) at a proximal end of a core wire (<NUM>), the sonic connector configured to couple to an ultrasound-producing mechanism (<NUM>, <NUM>) and transmit vibrational energy from the proximal end of the core wire (<NUM>) to a distal end portion of the core wire (<NUM>) for modifying intravascular lesions;
a damping mechanism (<NUM>) including a gasket system (<NUM>) around a proximal end portion of the core wire (<NUM>) in a damping-mechanism bore (<NUM>) of the catheter assembly, the damping mechanism (<NUM>) configured to damp a number of degrees of freedom of the vibrational energy not needed for modifying the intravascular lesions; and
a heat sink (<NUM>), characterised in that the heat sink includes a first annulus (<NUM>) at a first end of the gasket system (<NUM>), a second annulus (<NUM>) at a second, opposing end of the gasket system (<NUM>), and a plurality of longitudinal members (<NUM>) arranged around a circumference of the gasket system (<NUM>) configured to conduct and dissipate heat from the damping mechanism (<NUM>).