Patent Description:
Atherosclerosis is characterized by one or more intravascular lesions formed, in part, of plaque including blood-borne substances such as fat, cholesterol, and 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 wall thereof. A last point of patency often occurs at a boundary between the arterial lesion and the opposite wall of the arterial lumen. Surgical procedures for atherosclerosis such as angioplasty or atherectomy can be used to restore patency and blood flow lost to the one or more intravascular lesions.

An atherosclerotic surgical procedure can involve advancing one or more endoluminal devices to an intravascular lesion to modify the intravascular lesion. For example, angioplasty or atherectomy can involve advancing an endoluminal device over a guidewire to an intravascular lesion for modification thereof. However, advancing the endoluminal device over the guidewire to the intravascular lesion can lead to surgical complications from device complications, especially in tortuous anatomy where a tip of the endoluminal device can hang up and become derailed from the guidewire. Provided herein in some embodiments are linearly actuatable catheters, systems, and methods that address the foregoing. <CIT> discloses an ultrasound system having an ultrasound transducer having a transducer housing and a horn provided at the distal end of the transducer housing, an ultrasound transmission member, a sonic connector that is connected to the horn and the proximal end of the ultrasound transmission member and a catheter knob having a proximal end that is coupled to the distal end of the transducer housing.

The present invention is directed to the catheter assembly of claim <NUM>, the system of claim <NUM> and the method of claim <NUM>.

Provided herein is a catheter assembly including a core wire configured for linear actuation and a damping mechanism around the core wire configured to dampen vibrational energy. The core wire includes a proximal end with a sonic connector configured to couple to an ultrasound-producing mechanism for imparting vibrational energy to the core wire. The core wire includes a distal end configured to modify intravascular lesions with vibrational energy. The damping mechanism includes a gasket system and a retainer to retain the gasket system in a damping-mechanism bore of the catheter assembly. The damping mechanism is around a proximal-end portion of the core wire, where the damping mechanism is configured to dampen transverse wave-producing vibrational energy in the proximal-end portion of the core wire. The gasket system provides a compressive force sufficient to dampen transverse wave-producing vibrational energy in the proximal-end portion of the core wire without restricting the linear actuation of the core wire through the damping mechanism including extension and retraction of the core wire through the damping mechanism.

The catheter assembly further includes a linear actuation mechanism configured to extend the core wire from a fully retracted state of the core wire and retract the core wire from a fully extended state of the core wire. In the fully extended state, the distal end of the core wire and a working length of the core wire up to about <NUM> from a distal end of a sheath around the core wire is exposed. In the fully retracted state, the working length of the core wire up to at least the distal end of the core wire is concealed in the sheath.

In such embodiments, a center of the gasket system may be positioned over the core wire where the core wire experiences minimal transverse wave-producing vibrational energy, thereby reducing frictional heating and obviating a heat sink.

In such embodiments, the gasket system may include a number of axially and radially compressed O-rings in the damping-mechanism bore providing the compressive force around the core wire. The number of O-rings are axially compressed in the damping-mechanism bore by a distal end of the damping-mechanism bore and the retainer fixed in a proximal end of the damping-mechanism bore. The number of O-rings are radially compressed by an inner wall of the damping-mechanism bore.

In such embodiments, the catheter assembly may further include an injector configured to inject an irrigant into an irrigation port of the catheter assembly. The compressive force around the core wire is further sufficient to prevent irrigation backflow of the irrigant without restricting the extension or retraction of the core wire through the damping mechanism.

In such embodiments, the catheter assembly may further include a polymeric sleeve around an exposed portion of the proximal-end portion of the core wire between the sonic connector and the retainer. The polymeric sleeve is further around the proximal-end portion of the core wire in the damping mechanism, and the polymeric sleeve includes a lubricious surface to facilitate the extension and retraction of the core wire through the damping mechanism.

In such embodiments, the catheter assembly may further include an ultrasound transducer at the proximal end of the core wire forming a portion of an ultrasound-producing mechanism for imparting vibrational energy to the core wire.

Also provided herein is a catheter assembly including, a linear actuation mechanism, a core wire configured for linear actuation by the linear actuation mechanism, and a damping mechanism around the core wire configured to dampen vibrational energy. The core wire includes a proximal end with a sonic connector configured to accept vibrational energy imparted thereto. The core wire also includes a distal end with a tip member configured to modify intravascular lesions with vibrational energy. The damping mechanism includes a gasket system and a retaining washer to retain the gasket system in a damping-mechanism bore of the catheter assembly. The damping mechanism is around a proximal-end portion of the core wire, where the damping mechanism is configured to dampen transverse wave-producing vibrational energy in the proximal-end portion of the core wire. The gasket system provides a compressive force sufficient to dampen transverse wave-producing vibrational energy in the proximal-end portion of the core wire without restricting the linear actuation of the core wire through the damping mechanism including extension and retraction of the core wire through the damping mechanism.

The linear actuation mechanism is configured to extend the core wire from a fully retracted state of the core wire and retract the core wire from a fully extended state of the core wire. In the fully extended state, the tip member and a working length of the core wire up to about <NUM> from a distal end of a sheath around the core wire is exposed. In the fully retracted state, the working length of the core wire up to at least the tip member is concealed in the sheath.

In such embodiments, the gasket system may include a number of axially and radially compressed O-rings in the damping-mechanism bore providing the compressive force around the core wire. The compressive force is further sufficient to prevent irrigation backflow of an irrigant without restricting the extension or retraction of the core wire through the damping mechanism. The number of O-rings are axially compressed in the damping-mechanism bore by a distal end of the damping-mechanism bore and the retaining washer fixed in a proximal end of the damping-mechanism bore. The number of O-rings are radially compressed by an inner wall of the damping-mechanism bore.

In such embodiments, the catheter assembly may further include a polymeric sleeve around the proximal-end portion of the core wire in the damping mechanism. The polymeric sleeve includes a lubricious surface to facilitate a full extent of the linear actuation of the core wire through the damping mechanism.

In such embodiments, the ultrasound transducer is configured for linear actuation by the linear actuation mechanism. The linear actuation of the ultrasound transducer is in sync with the linear actuation of the core wire to maintain a sonic connection between the ultrasound transducer and the core wire through the sonic connector.

Also provided herein is a system including, a catheter assembly and an ultrasonic energy-producing mechanism. The catheter assembly includes a linear actuation mechanism, a core wire configured for linear actuation by the linear actuation mechanism, and a damping mechanism around the core wire configured to dampen vibrational energy. The core wire includes a proximal end with a sonic connector configured to accept vibrational energy imparted thereto. The core wire also includes a distal end with a tip member configured to modify intravascular lesions with vibrational energy. The damping mechanism includes a gasket system and a retaining washer to retain the gasket system in a damping-mechanism bore of the catheter assembly. The damping mechanism is around a proximal-end portion of the core wire, where the damping mechanism is configured to dampen transverse wave-producing vibrational energy in the proximal-end portion of the core wire. The gasket system provides a compressive force sufficient to dampen transverse wave-producing vibrational energy in the proximal-end portion of the core wire without restricting the linear actuation of the core wire through the damping mechanism including extension and retraction of the core wire through the damping mechanism. The ultrasonic energy-producing mechanism includes an ultrasound generator and an ultrasound transducer. The ultrasound transducer is configured to impart vibrational energy to the sonic connector at the proximal end of the core wire.

In such embodiments, the linear actuation mechanism is configured to extend the core wire from a fully retracted state of the core wire and retract the core wire from a fully extended state of the core wire. In the fully extended state, the tip member and a working length of the core wire up to about <NUM> from a distal end of a sheath around the core wire is exposed. In the fully retracted state, the working length of the core wire up to at least the tip member is concealed in the sheath.

In such embodiments, the system may further include a polymeric sleeve around the proximal-end portion of the core wire in the damping mechanism. The polymeric sleeve includes a lubricious surface to facilitate a full extent of the linear actuation of the core wire through the damping mechanism.

In such embodiments, the system further may further include a console including a foot switch and the ultrasonic energy-producing mechanism including the ultrasound generator and the ultrasound transducer. The foot switch is configured to activate and deactivate the ultrasonic energy-producing mechanism.

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

Also provided herein is a method including, molding a cartridge of a catheter assembly and assembling a damping mechanism around a core wire in the cartridge. Molding the cartridge includes molding the cartridge with a damping-mechanism bore. Assembling the damping mechanism around the core wire in the cartridge includes disposing the core wire through a center of the damping-mechanism bore coincident with a rotational axis of the cartridge. A number of O-rings are disposed in the damping-mechanism bore around the core wire, and a washer is fixed in a proximal end of the damping-mechanism bore to form the damping mechanism around the core wire. Fixing the washer in the proximal end of the damping-mechanism bore generates a radial compressive force on the core wire from axially compressing the number of O-rings against a distal end of the damping-mechanism bore. Axially compressing the number of O-rings against the distal end of the damping-mechanism bore, in turn, generates the radial compressive force on the core wire from radially compressing the number of O-rings against an inner wall of the damping-mechanism bore opposing the core wire. The radial compressive force is sufficient to dampen transverse wave-producing vibrational energy imparted to a proximal-end portion of the core wire without restricting linear actuation of the core wire through the damping mechanism.

In such embodiments, the method may further include 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. The polymeric sleeve is formed of a lubricious polymer to facilitate a full extent of the linear actuation of the core wire through the damping mechanism.

In such embodiments, the method may further include molding a housing of a catheter assembly; disposing the cartridge with the damping mechanism around the core wire in the housing of the catheter assembly; and connecting the core wire to an linear actuation mechanism of the catheter assembly. Thereby, the core wire of the catheter assembly is configured for the linear actuation through the damping mechanism.

These and other features of the concepts provided herein may be better understood with reference to the drawings, description, and appended claims.

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.

Regarding terminology used herein, it should also be understood the terminology is for the purpose of describing some particular embodiments, and the terminology does not limit the scope of the concepts provided herein. Unless indicated otherwise, ordinal numbers (e.g., first, second, third, etc.) are used to distinguish or identify different features or steps in a group of features or steps, and do not supply a serial or numerical limitation. It should also be understood that, unless indicated otherwise, any 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. It should also be understood that the singular forms of "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

With respect to "proximal," a "proximal portion" or a "proximal-end portion" of, for example, a sheath or core wire respectively includes a portion of the sheath or core wire near a system operator when the system is used as intended. Likewise, a "proximal length" of, for example, the sheath or core wire respectively includes a length of the sheath or core wire near the system operator when the system is used as intended. A "proximal end" of, for example, the sheath or core wire respectively includes an end of the sheath or core wire near the system operator when the system is used as intended. The proximal portion, the proximal-end portion, or the proximal length of the sheath or core wire can include the proximal end of the sheath or core wire; however, the proximal portion, the proximal-end portion, or the proximal length of the sheath or core wire need not include the proximal end of the sheath or core wire. That is, unless context suggests otherwise, the proximal portion, the proximal-end portion, or the proximal length of the sheath or core wire is not a terminal portion or terminal length of the sheath or core wire.

With respect to "distal," a "distal portion" or a "distal-end portion" of, for example, a sheath or core wire respectively includes a portion of the sheath or core wire away from a system operator when the system is used as intended. Likewise, a "distal length" of, for example, the sheath or core wire respectively includes a length of the sheath or core wire away from the system operator when the system is used as intended. A "distal end" of, for example, the sheath or core wire respectively includes an end of the sheath or core wire away from the system operator when the system is used as intended. The distal portion, the distal-end portion, or the distal length of the sheath or core wire can include the distal end of the sheath or core wire; however, the distal portion, the distal-end portion, or the distal length of the sheath or core wire need not include the distal end of the sheath or core wire. That is, unless context suggests otherwise, the distal portion, the distal-end portion, or the distal length of the sheath or core wire is not a terminal portion or terminal length of the sheath or core wire.

An atherosclerotic surgical procedure can involve advancing one or more endoluminal devices to an intravascular lesion to modify the intravascular lesion. For example, angioplasty or atherectomy can involve advancing an endoluminal device over a guidewire to an intravascular lesion for modification thereof. However, advancing the endoluminal device over the guidewire to the intravascular lesion can lead to surgical complications from device complications, especially in tortuous anatomy where a tip of the endoluminal device can hang up and become derailed from the guidewire. Provided herein in some embodiments are linearly actuatable catheters, systems, and methods that address 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> 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 a system operator an instrument for monitoring and controlling the system <NUM> and various sub-systems and functions thereof. The console <NUM> includes an ultrasonic energy-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 ultrasonic energy-producing mechanism is divided between the console <NUM> and the catheter assembly <NUM>. The ultrasonic energy-producing mechanism is configured to convert an electric current into a 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 include a foot switch <NUM> configured to activate and deactivate the system <NUM> such as activate and deactivate a core wire <NUM> (e.g., a nitinol core wire) of the catheter assembly <NUM>. The core wire <NUM> is disposed in a core-wire lumen <NUM> of a sheath <NUM> of the catheter assembly <NUM>. A proximal end of the core wire <NUM> is vibrationally coupled to the ultrasound transducer <NUM>, and a distal end of the core wire <NUM> is vibrationally coupled to a lesion-modifying tip member <NUM> or a lesion-modifying tip <NUM> is fashioned from the distal end of the core wire <NUM>. As such, the core wire <NUM> is configured to transfer the vibrational energy from the ultrasound transducer <NUM> to the tip member or tip <NUM> for modifying intravascular lesions. When the system <NUM> is powered on but not activated, the foot switch <NUM> is used to activate the system <NUM>, thereby activating the ultrasound transducer <NUM>, the core wire <NUM>, and the tip member or tip <NUM> of the catheter assembly <NUM>. When the system <NUM> is powered on and activated, the foot switch <NUM> is used to deactivate the system <NUM>, thereby deactivating the ultrasound transducer <NUM>, the core wire <NUM>, and the tip member or tip <NUM> of the catheter assembly <NUM>.

The console <NUM> optionally further include 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-modification procedure (e.g., crossing an intravascular lesion, ablating an intravascular lesion, etc.), cooling the core wire <NUM> of the catheter assembly <NUM>, or a combination thereof.

The console <NUM> optionally further include both the foot switch <NUM> and the injector <NUM>. In such embodiments, the foot switch <NUM> is 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> with an extension-retraction mechanism or linear actuation mechanism <NUM> configured to extend the core wire <NUM> from a first, fully retracted position or state of the core wire <NUM> in accordance with some embodiments. <FIG> provides a schematic illustrating the catheter assembly <NUM> with the extension-retraction mechanism or linear actuation mechanism <NUM> configured to retract the core wire <NUM> from a second, fully extended position or state of the core wire <NUM> in accordance with some embodiments. The catheter assembly <NUM> includes a housing <NUM> coupled to a catheter body <NUM> (see <FIG>) including the sheath <NUM> and core wire <NUM> 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> and <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> and <FIG>, as the irrigation port <NUM> is optional in some embodiments. ) Locking the housing <NUM> onto the ultrasound transducer <NUM> ensures the proximal end of the core wire <NUM> is sufficiently vibrationally coupled to the ultrasound transducer <NUM> for modifying intravascular lesions. Again, the catheter assembly <NUM> alternatively includes the ultrasound transducer <NUM>, which divides the ultrasonic energy-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, thereby obviating the lock collar <NUM> shown in <FIG> and <FIG>. Further in such embodiments, the ultrasound transducer <NUM> is configured for linear actuation by the linear actuation mechanism <NUM>. The linear actuation of the ultrasound transducer <NUM> is in sync with the linear actuation of the core wire <NUM> to maintain a sonic connection between the ultrasound transducer <NUM> and the core wire <NUM> through sonic connector <NUM>. (See <FIG> and <FIG> for the sonic connector <NUM>.

The linear actuation mechanism <NUM> is configured to extend the core wire <NUM> from the first, fully retracted position or state of the core wire <NUM> as shown in <FIG>. In the fully retracted state of the core wire <NUM>, the distal portion of the core wire <NUM> including the tip member or tip <NUM> is wholly disposed within the sheath lumen <NUM>. Alternatively, in the fully retracted state of the core wire <NUM>, the tip member or tip <NUM> is exposed and a remaining distal portion of the core wire <NUM> is wholly disposed within the sheath lumen <NUM>. The linear actuation mechanism <NUM> is further configured to retract the core wire <NUM> from the second, fully extended position or state of the core wire <NUM> as shown in <FIG>. In the fully extended state of the core wire <NUM>, a maximum working length lw(max) of the core wire <NUM> including the tip member or tip <NUM> is exposed outside the sheath lumen <NUM>.

It should be understood that the linear actuation mechanism <NUM> is configured to extend the core wire <NUM> in a distal direction and retract the core wire <NUM> in a proximal direction. Furthermore, the linear actuation mechanism <NUM> is configured to linearly actuate the core wire <NUM> itself as opposed to any other wire for any other motion of the core wire <NUM> (e.g., a pulling wire for articulation such as deflection of the core wire <NUM> through an angle).

As shown in <FIG> and <FIG>, the housing <NUM> is configured to accommodate a proximal length of the core wire <NUM>, and the linear actuation mechanism <NUM> is configured to extend the proximal length of the core wire <NUM> from the housing <NUM> and expose a working length lw of the distal portion of the core wire <NUM> for ultrasound-based modification of one or more intravascular lesions with the working length lw of the core wire <NUM>. A maximum working length lw(max) of the core wire <NUM> is defined by an extension distance over which a point on the core wire <NUM> extends from the first, fully retracted state to the second, fully extended state. The maximum working length lw(max) of the core wire <NUM> is also be defined by a slot length ls in the housing <NUM> configured to accommodate the proximal length of the core wire <NUM> in the first state. The working length lw of the core wire <NUM> ranges between about <NUM> and <NUM>, including between about <NUM> and <NUM> or between about <NUM> and <NUM>; however the working length lw of the core wire <NUM> is not limited thereto. It should be appreciated that shorter working lengths lw, and smaller catheter-body profiles have benefits in certain instances, whereas longer working lengths lw and larger catheter-body profiles have benefits in certain other instances (e.g., larger patients).

The linear actuation mechanism <NUM> is hand actuated as shown in <FIG> and <FIG>, or the linear actuation mechanism <NUM> is motor actuated. Whether hand actuated or motor actuated, the linear actuation mechanism <NUM> is configured to i) extend the core wire <NUM> from the first, fully retracted state of the core wire <NUM>, ii) retract the core wire <NUM> from the second, fully extended state of the core wire <NUM>, iii) extend or retract the core wire <NUM> into intermediate positions or states between the first state and the second state, or iv) any combination thereof. Extension and retraction of the core wire <NUM> into the foregoing intermediate positions provides customizability as needed for different anatomy and intravascular lesions.

The working length lw of the distal portion of the core wire <NUM> beyond the sheath <NUM> or the sheath lumen <NUM> thereof is configured for displacement to effect intravascular lesion modification. The displacement includes 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 lw of the core wire <NUM> results in micromotion such as cavitation, and transverse displacement of the working length lw 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> and <FIG> provide schematics illustrating a damping mechanism <NUM> configured for both damping vibrational energy in the core wire <NUM> and linear actuation of the core wire <NUM> therethrough in accordance with some embodiments.

The core wire <NUM> includes a sonic connector <NUM> at a proximal end of the core wire <NUM> configured to connect to an ultrasound-producing mechanism for imparting vibrational energy to the core wire for ultrasound-based modification of one or more intravascular lesions with the working length lw of the core wire <NUM>. The sonic connector <NUM> is configured to connect to the ultrasound-producing mechanism by the ultrasound transducer <NUM> or an intervening ultrasonic horn (not shown). The distal end of the core wire <NUM> is vibrationally coupled to the lesion-modifying tip member <NUM> or the lesion-modifying tip <NUM> is fashioned from the distal end of the core wire <NUM> for ultrasound-based modification of one or more intravascular lesions.

The catheter assembly <NUM> includes the damping mechanism <NUM> about the proximal-end portion of the core wire <NUM> configured to dampen transverse wave-producing vibrational energy about the proximal-end portion of the core wire <NUM> in favor of longitudinal wave-producing vibrational energy without restricting the extension or retraction of the core wire <NUM> through the damping mechanism <NUM>. The damping mechanism <NUM> includes a gasket system <NUM> configured to exert a compressive force around the core wire <NUM> and a retainer <NUM> configured to retain the gasket system <NUM> within a damping-mechanism bore <NUM> of a cartridge <NUM> of the catheter assembly <NUM>.

The gasket system <NUM> includes a number of O-rings <NUM>. The number of O-rings <NUM> range from <NUM> O-ring to <NUM> O-rings, including <NUM> O-rings, such as <NUM> O-rings, for example, <NUM> O-rings. The number of O-rings <NUM> are axially compressed in the damping-mechanism bore <NUM> of the cartridge <NUM> 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 number of O-rings <NUM> generates a radial compression on the core wire <NUM> sufficient to dampen the transverse wave-producing vibrational energy in favor of the longitudinal wave-producing vibrational energy about the proximal portion of the core wire <NUM>.

The damping mechanism <NUM> further includes a sleeve <NUM> around the core wire <NUM>. (Alternatively, the sleeve <NUM> is considered a part of the linear actuation mechanism <NUM> in that it facilitates the extension and retraction of the core wire <NUM> through the damping mechanism <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> therebetween. The sleeve <NUM> is further around at least the proximal-end portion of the core wire <NUM> in the damping mechanism <NUM>, as well as around the core wire <NUM> distal to the damping mechanism <NUM> up to at least a length commensurate with the working length lw of the core wire <NUM>. Not only does the sleeve <NUM> prevent fatigue of the core wire <NUM>, the sleeve <NUM> also facilitates the extension and retraction of the core wire <NUM> through the damping mechanism <NUM>. The sleeve <NUM> includes or otherwise be formed of a polymer providing a relatively lubricious surface that facilitates the extension and retraction of the core wire <NUM> through the damping mechanism <NUM>.

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 effected 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.

The damping mechanism <NUM> is centered over or a vibrational node of the core wire <NUM>, or the core wire <NUM> can be adjusted such that the damping mechanism <NUM> is over or a vibrational node of the core wire <NUM>. This minimizes frictional heating caused by damping the transverse wave-producing vibrational energy, and, thereby, obviates a need for a heat sink in the damping mechanism <NUM> of the catheter assembly <NUM>. 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 gasket system <NUM> further prevents the irrigation backflow without restricting the extension or retraction of the core wire <NUM> through the damping mechanism <NUM>.

Making the damping mechanism <NUM> configured for both damping vibrational energy in the core wire <NUM> and linear actuation of the core wire <NUM> therethrough includes molding the cartridge <NUM> of the catheter assembly <NUM> and subsequently assembling the damping mechanism <NUM> around the core wire <NUM> in the cartridge <NUM>.

Molding the cartridge <NUM> includes molding the cartridge <NUM> with a damping-mechanism bore <NUM>. Such molding includes, but is not limited to, compression molding, injection molding, thermoforming, or a combination thereof.

Assembling the damping mechanism <NUM> around the core wire <NUM> in the cartridge <NUM> includes disposing the core wire <NUM> through a center of the damping-mechanism bore <NUM> coincident with a rotational axis of the cartridge <NUM>. Prior to disposing the core wire <NUM> through the center of the damping-mechanism bore <NUM>, the core wire <NUM> is disposed in a heat-shrinkable polymeric sleeve 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>. The polymeric sleeve <NUM> is formed of a lubricious polymer (e.g., PTFE) to facilitate a full extent of the linear actuation (i.e., linear actuation from the first, fully retracted state to the second, fully extended state and back again) of the core wire <NUM> through the damping mechanism <NUM>.

Assembling the damping mechanism <NUM> around the core wire <NUM> in the cartridge <NUM> further includes disposing the number of O-rings <NUM> in the damping-mechanism bore <NUM> around the core wire <NUM>, as well as fixing the retainer <NUM> (e.g., an external star washer) in a proximal end of the damping-mechanism bore <NUM> to form the damping mechanism <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 number of O-rings <NUM> resulting from axially pressing the number of O-rings <NUM> 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 number of O-rings <NUM>, thereby, radially pressing the number of O-rings <NUM> against an inner wall of the damping-mechanism bore <NUM> opposing the core wire <NUM> and the core wire <NUM> itself. The radial compressive force is sufficient to dampen transverse wave-producing vibrational energy imparted to the proximal-end portion of the core wire <NUM> without restricting the linear actuation of the core wire <NUM> through the damping mechanism <NUM>.

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 core wire <NUM> to the linear actuation mechanism <NUM> of the catheter assembly <NUM>. Thereby, the core wire <NUM> of the catheter assembly <NUM> is configured for the linear actuation through the damping mechanism <NUM>.

Claim 1:
A catheter assembly (<NUM>), comprising:
a core wire (<NUM>) configured for linear actuation including extension and retraction, wherein:
a proximal end of the core wire includes a sonic connector (<NUM>) configured to couple to an ultrasound-producing mechanism for imparting vibrational energy to the core wire (<NUM>), and
a distal end of the core wire (<NUM>) is configured to modify intravascular lesions with vibrational energy; and
a damping mechanism (<NUM>) around a proximal-end portion of the core wire configured to dampen transverse wave-producing vibrational energy in the proximal-end portion of the core wire (<NUM>), the damping mechanism including:
a gasket system (<NUM>) configured to exert a compressive force around the core wire (<NUM>); and
a retainer (<NUM>) to retain the gasket system (<NUM>) in a damping-mechanism bore (<NUM>) of the catheter assembly, wherein the compressive force is sufficient to dampen transverse wave-producing vibrational energy in the proximal-end portion of the core wire without restricting the extension or retraction of the core wire (<NUM>) through the damping mechanism (<NUM>), and
a linear actuation mechanism (<NUM>) configured to:
extend the core wire (<NUM>) from a fully retracted state of the core wire, and
retract the core wire from a fully extended state of the core wire, wherein:
the distal end of the core wire and a working length of the core wire (<NUM>) up to <NUM> from a distal end of a sheath (<NUM>) around the core wire are exposed in the fully extended state, and
the working length of the core wire up to at least the distal end of the core wire are concealed in the sheath (<NUM>) in the fully retracted state.