Patent Description:
This application generally relates to systems and methods for modifying intravascular lesions.

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 side of an arterial lumen and build out across the lumen to an opposite side thereof. A last point of patency often occurs at a boundary between the arterial lesion and the opposite side of the arterial lumen.

Surgical procedures for atherosclerosis such as atherectomy and angioplasty can be used to restore patency and blood flow lost to the one or more intravascular lesions; however, a number of different devices are needed to perform any one of the surgical procedures. For example, atherectomy can involve placing a guidewire through an intravascular lesion with a first, lesion-crossing device and subsequently advancing a second, atherectomy device to the lesion for ablation thereof. Each of a number of different devices needs to be inserted into and removed from a patient, thereby increasing a risk of surgical complication. Accordingly, there is a need to reduce the number of different devices used for surgical procedures for atherosclerosis. Provided herein in some embodiments are systems and methods that address the foregoing. <CIT> discloses a method for operating an ultrasound vibration element having proximal and distal ends, the distal end vibrating in a longitudinal direction of the distal end of the ultrasound vibration element and a portion of the ultrasound vibration element vibrating in a direction perpendicular to the longitudinal direction of the distal end of the ultrasound vibration element. <CIT> discloses an ultrasound system having a catheter including an elongate flexible catheter body having at least one lumen extending longitudinally therethrough. The catheter further includes an ultrasound transmission member extending longitudinally through the lumen of the catheter body, the distal end of the catheter body being deflectable.

The present invention is directed to the system of claim <NUM>. The dependent claims refer to preferred embodiments. No methods are claimed.

Provided herein in some embodiments is a system including a console and a catheter assembly. The console includes an ultrasound-producing mechanism configured to convert an electric current into a vibrational energy. The console also includes a driving-parameter modifier configured to modify driving parameters to selectively provide one or more output modes for the vibrational energy. The catheter assembly includes a sheath including a sheath lumen and a core wire at least partially disposed within the sheath lumen. The core wire includes a proximal portion and a distal portion of the core wire, wherein the proximal portion of the core wire is coupled to the ultrasound-producing mechanism. A working length of the distal portion of the core wire beyond the sheath is configured for longitudinal, transverse, or longitudinal and transverse displacement in accordance with the one or more output modes for the vibrational energy to effect different intravascular lesion-modification procedures.

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.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to those of ordinary skill in the art.

Atherosclerosis is characterized by one or more intravascular lesions formed in part of plaque including blood-borne substances such as fat, cholesterol, and calcium. Surgical procedures for atherosclerosis such as atherectomy and angioplasty can be used to restore patency and blood flow lost to the one or more intravascular lesions; however, a number of different devices are needed to perform any one of the surgical procedures. For example, atherectomy can involve placing a guidewire through an intravascular lesion with a first, lesion-crossing device and subsequently advancing a second, atherectomy device to the lesion for ablation thereof. Each of the number of different devices needs to be inserted into and removed from a patient, thereby increasing a risk of surgical complication. Accordingly, there is a need to reduce the number of different devices used for surgical procedures for atherosclerosis. Provided herein in some embodiments are systems and methods that address the foregoing.

For example, provided herein in some embodiments is a system including a console and a catheter assembly. The console includes an ultrasound-producing mechanism configured to convert an electric current into a vibrational energy. The console also includes a driving-parameter modifier configured to modify driving parameters to selectively provide one or more output modes for the vibrational energy. The catheter assembly includes a sheath including a sheath lumen and a core wire at least partially disposed within the sheath lumen. The core wire includes a proximal portion and a distal portion of the core wire, wherein the proximal portion of the core wire is coupled to the ultrasound-producing mechanism. A working length of the distal portion of the core wire beyond the sheath is configured for longitudinal, transverse, or longitudinal and transverse displacement in accordance with the one or more output modes for the vibrational energy to effect different intravascular lesion-modification procedures.

In some embodiments, the one or more output modes include at least an atherectomy mode and a crossing mode to respectively ablate and cross intravascular lesions. Each of the atherectomy mode and the crossing mode, in turn, can include one or more output modes thereof.

<FIG> provides a schematic illustrating a system <NUM> in accordance with some embodiments. As shown, the system <NUM> can include a console <NUM> and a catheter assembly <NUM>.

The console <NUM> provides a system operator an instrument for monitoring and controlling the system and various sub-systems and functions thereof. The console <NUM> can include an ultrasound-producing mechanism including an ultrasound generator <NUM> and an ultrasound transducer <NUM>. The ultrasound-producing mechanism can be configured to convert an electric current into a vibrational energy. For example, the ultrasound generator <NUM> can be 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, can be configured to convert the high-frequency current into the vibrational energy (e.g., > <NUM> such as <NUM> ± <NUM>). The console <NUM> can also include a driving-parameter modifier <NUM> configured to modify driving parameters to selectively provide one or more output modes for the vibrational energy. The one or more output modes for the vibrational energy can effect different intravascular lesion-modification procedures with the core wire of the catheter assembly <NUM>. The core wire can be configured for longitudinal, transverse, or longitudinal and transverse displacement at a distal end of the core wire in accordance with one or more output modes for the vibrational energy.

In some embodiments, the console <NUM> can further include a foot switch <NUM> configured to activate and deactivate the system such as activate and deactivate the core wire of the catheter assembly <NUM>. For example, when the system <NUM> is powered on but not activated, the foot switch <NUM> can be used to activate the system <NUM>, thereby activating the core wire of the catheter assembly <NUM>. When the system <NUM> is powered on and activated, the foot switch <NUM> can be used to deactivate the system <NUM>, thereby deactivating the core wire of the catheter assembly <NUM>. In some embodiments, the console <NUM> can further include an injector <NUM> configured to inject an irrigant into an optional irrigation lumen <NUM> of the catheter assembly <NUM>. The irrigant can be, for example, sterile saline for irrigating an anatomical area undergoing an intravascular lesion-modification procedure, cooling the core wire of the catheter assembly, or a combination thereof. In some embodiments, the console <NUM> can further include 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>.

The driving-parameter modifier <NUM> can be configured to modify any of a number of drive parameters including, but not limited to, at least the driving parameters selected from pulse repetition frequency, duty cycle, and a combination of the pulse repetition frequency and the duty cycle to effect the different intravascular lesion-modification procedures. The driving-parameter modifier <NUM> can include any of a number of controls including, but not limited to, buttons, switches, knobs, wheels, or a combination thereof for a system operator to switch between the atherectomy mode and the crossing mode, modify any of the number of drive parameters, or a combination thereof.

<FIG> provides a graph illustrating pulse repetition frequency and duty cycle driving parameters in accordance with some embodiments.

With respect to pulse repetition frequency, a number of pulses such as ultrasonic pulses from an ultrasound transducer can occur over a particular time interval Δtime as shown in <FIG>. Each pulse of the number of pulses can have a pulse width ("PW") measured in a unit of time such as a fraction of Δtime, and the time between the start of any two consecutive pulses can define a pulse repetition period ("PRP"). The pulse repetition frequency ("PRF") is the inverse of the pulse repetition period; that is, PRF = PRP-<NUM>. When Δtime is one second, for example, the pulse repetition frequency can be expressed in the number of pulses per second or Hz. <FIG> provides an example <NUM>-Hz pulse repetition frequency for a <NUM>-second Δtime.

With respect to duty cycle, the duty cycle is a duty factor expressed as a fraction of <NUM> (i.e., a percentage). The duty factor ("DF"), in turn, is a fraction of the pulse repetition period each pulse of the number of pulses is present during the pulse repetition period. Each pulse is considered present during the pulse repetition period over its pulse width. As such, DF = PW/PRP, and DC = DF x <NUM>. <FIG> provides an example duty factor of about <NUM> and duty cycle of about <NUM>%.

The driving-parameter modifier <NUM> can be configured to modify the pulse repetition frequency to provide, for example, transverse displacement of the core wire at a sufficient amplitude to effect atherectomy procedures. A pulse repetition frequency between about <NUM> and <NUM>, including about <NUM> and <NUM>, such as about <NUM> and <NUM>, can provide the transverse displacement of the core wire at the sufficient amplitude to effect the atherectomy procedures. A duty cycle between about <NUM>% and <NUM>% for the pulse repetition frequency between about <NUM> and <NUM> can further provide the transverse displacement of the core wire at the sufficient amplitude to effect the atherectomy procedures. The duty cycle between about <NUM>% and <NUM>% for the pulse repetition frequency between about <NUM> and <NUM> can even further provide the transverse displacement of the core wire at the sufficient amplitude to effect the atherectomy procedures.

The driving-parameter modifier <NUM> can be configured to modify the duty cycle to provide, for example, longitudinal displacement of the core wire at a sufficient amplitude to effect intravascular lesion-crossing procedures. A duty cycle between about <NUM>% and <NUM>%, including about <NUM>% and <NUM>%, such as about <NUM>% and <NUM>%, can provide the longitudinal displacement of the core wire at the sufficient amplitude to effect the intravascular lesion-crossing procedures. A pulse repetition frequency between about <NUM> and <NUM> for the duty cycle between about <NUM>% and <NUM>% for can further provide the longitudinal displacement of the core wire at the sufficient amplitude to effect the intravascular lesion-crossing procedures. For a duty cycle of about <NUM>%, pulse repetition frequency becomes a smaller component in providing the longitudinal displacement of the core wire at the sufficient amplitude to effect the intravascular lesion-crossing procedures. Any pulse repetition frequency including a pulse repetition frequency between about <NUM> and <NUM> for the duty cycle of about <NUM>% can even further provide the longitudinal displacement of the core wire at the sufficient amplitude to effect the intravascular lesion-crossing procedures.

Dimensional and/or material modifications to the core wire of the catheter assembly <NUM> can affect the pulse repetition frequency and the duty cycle for effecting the different intravascular lesion-modification procedures. As such, it should be understood that the driving-parameter modifier <NUM> is not limited in its configuration to modify the pulse repetition frequency in the foregoing <NUM>-<NUM> range. In some embodiments, the driving-parameter modifier <NUM> can be further configured to modify the pulse repetition frequency to less than about <NUM>, greater than about <NUM>, or less than about <NUM> and greater than about <NUM>. It should also be understood that the driving-parameter modifier <NUM> is not limited in its configuration to modify the duty cycle in the foregoing <NUM>-<NUM>% range. In some embodiments, the driving-parameter modifier <NUM> can be further configured to modify the duty cycle to less than about <NUM>%.

<FIG> provides a schematic illustrating a catheter assembly <NUM> of the system <NUM> in accordance with some embodiments.

The catheter assembly <NUM> can include a sheath <NUM> including a sheath lumen <NUM> and a core wire <NUM> at least partially disposed within the sheath lumen <NUM>. The core wire <NUM> can include a proximal portion <NUM> and a distal portion <NUM> of the core wire, wherein the proximal portion <NUM> of the core wire <NUM> can be coupled to the ultrasound-producing mechanism by a sonic connector <NUM> (see <FIG> and <FIG>) to the ultrasound transducer <NUM> or an intervening ultrasonic horn. A working length <NUM> of the distal portion <NUM> of the core wire <NUM> beyond the sheath <NUM> can be configured for displacement in accordance with the one or more output modes for the vibrational energy to effect different intravascular lesion-modification procedures. The working length <NUM> of the core wire <NUM> can range between about <NUM> and <NUM>, including about <NUM> and <NUM> or <NUM> and <NUM>.

The working length <NUM> of the core wire <NUM> can be configured for longitudinal, transverse, or longitudinal and transverse displacement in accordance with the one or more output modes for the vibrational energy including the crossing mode and the atherectomy mode. Longitudinal displacement of the working length <NUM> of the core wire <NUM> can result in micromotion such as cavitation, and transverse displacement of the working length <NUM> of the core wire <NUM> can result in macromotion. In the crossing mode, the micromotion can be used to cross intravascular lesions. In the atherectomy mode, the macromotion coupled with the micromotion can be used to ablate intravascular lesions, thereby breaking the lesions into minute fragments and restoring patency and blood flow.

The core wire <NUM> can be configured without a tip, thereby eliminating surgical procedure-based complications resulting from tip breakage such as tip separation from the core wire <NUM>. To further eliminate surgical procedure-based complications, the core wire <NUM> can be bulked up in the distal portion <NUM> such as at a distal end of the core wire <NUM> to provide a more durable distal portion <NUM>, thereby mitigating surgical procedure-based wire breakage in the distal portion <NUM> of the core wire <NUM>. A bulked-up distal portion <NUM> of the core wire <NUM> includes an increased mass in the distal portion <NUM> of the core wire compared to tapered core wires. The increased mass can result from an increased size of the distal portion <NUM> of the core wire, an increased density of the distal portion <NUM> of the core wire, or a combination thereof. In addition to mitigating surgical procedure-based wire breakage in the distal portion <NUM> of the core wire <NUM>, the bulked-up distal portion <NUM> of the core wire can provide an anchor and a nodal location for producing longitudinal displacement in the core wire <NUM>.

<FIG> and <FIG> provide schematics illustrating a buckling section of a core wire of a catheter assembly in accordance with some embodiments.

In some embodiments, the core wire <NUM> can include a buckling section <NUM> configured to produce transverse displacement in the working length of the core wire <NUM> by buckling in accordance with the one or more output modes for the vibrational energy. The buckling section <NUM> can be within a medial portion <NUM> of the core wire <NUM> between the proximal portion <NUM> and the distal portion <NUM> of the core wire. The medial portion <NUM> of the core wire <NUM> can include a tapered section <NUM> and an inversely tapered section <NUM> of the core wire <NUM>, and the buckling section <NUM> can be between the tapered section <NUM> and the inversely tapered section <NUM> with a cross-sectional area smaller than either one of the tapered section <NUM> or the inversely tapered section <NUM>. The buckling section <NUM> can be at least about <NUM>" long, including at least about <NUM>" long, such as at least about <NUM>" long, for example, at least about <NUM>" long. In some embodiments, the buckling section can be about <NUM>-<NUM>" long.

<FIG> and <FIG> provide schematics illustrating a damping mechanism of a catheter assembly in accordance with some embodiments.

The catheter assembly <NUM> can include a damping mechanism about the proximal portion <NUM> of the core wire <NUM> configured to dampen transversely oriented vibrational energy in favor of longitudinally oriented vibrational energy about the proximal portion <NUM> of the core wire <NUM>, as well as prevent fatigue of the core wire <NUM>. The damping mechanism can include a sleeve <NUM> encasing the core wire <NUM> with a first radial compressive force; a gasket system <NUM> encasing the sleeve <NUM> with a second radial compressive force; and a retainer <NUM> configured to retain the gasket system <NUM> within a damping-mechanism bore <NUM> of the catheter assembly <NUM>. The sleeve <NUM> encasing the core wire <NUM> can be a polymeric sleeve <NUM> such as a polytetrafluoroethylene ("PTFE") sleeve <NUM>. The first radial compressive force of the sleeve <NUM> on the core wire <NUM> can range from that associated 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 the core wire <NUM> and the sleeve <NUM>. In some embodiments, the first radial compressive force of the sleeve <NUM> on the core wire <NUM> is associated with a transition fit or an interference fit. The transition fit and the interference fit can be effected by, for example, heat-shrinking a suitably sized PTFE for the desired fit about the core wire <NUM> during assembly of the catheter assembly <NUM>.

The gasket system <NUM> can include a number of O-rings <NUM>. The number of O-rings <NUM> can range from <NUM> O-ring to <NUM> O-rings, including <NUM> O-rings, such as <NUM> O-rings, for example, <NUM> O-rings. The O-rings <NUM> can be compressed in the damping-mechanism bore <NUM> of the catheter assembly <NUM> and retained in the damping-mechanism bore <NUM> with a longitudinal compression by the retainer <NUM>, for example, a washer. The longitudinal compression contributes to a radial compression on the core wire <NUM> sufficient to dampen transversely oriented vibrational energy in favor of longitudinally oriented vibrational energy about the proximal portion <NUM> of the core wire <NUM>. The damping mechanism can be centered over a vibrational node of the core wire <NUM> to minimize frictional heating caused by damping the transversely oriented vibrational energy. Minimized frictional heating obviates a need for a heat sink in the damping mechanism of the catheter assembly <NUM>. In embodiments of the system <NUM> including the injector <NUM>, the gasket system <NUM> can prevent irrigation backflow of the irrigant through the catheter assembly <NUM> and into the ultrasound-producing mechanism.

<FIG> provides a schematic illustrating a guidewire rail of a catheter assembly in accordance with some embodiments.

The catheter assembly <NUM> can further include a guidewire rail <NUM> comprising a guidewire-rail lumen <NUM> externally fixed to the sheath <NUM> such as side-by-side with the sheath <NUM>. The guidewire rail <NUM> can terminate about a distal sheath terminus where the working length of the core wire <NUM> is free to transversely displace without interacting with the guidewire rail <NUM>, a guidewire G wholly or partially disposed within the guidewire-rail lumen <NUM>, or a combination of the guidewire rail <NUM> and the guidewire G. Thus, subtleties associated with drive parameter modifications (e.g., modification of the pulse repetition frequency, the duty cycle, etc.) for the one or more output modes of the vibrational energy are not affected.

A system in accordance with some embodiments was used to modify the drive parameters including the pulse repetition frequency and the duty cycle to determine values therefor for effecting at least the atherectomy mode and the crossing mode. The efficacy of the atherectomy mode and the crossing mode to respectively ablate and cross intravascular lesions was also qualitatively determined. With respect to the atherectomy output mode, it was determined that a pulse repetition frequency between about <NUM> and <NUM> and a duty cycle between about <NUM>% and <NUM>% can provide the transverse displacement of the core wire at a sufficient amplitude to effect the atherectomy procedures. Table <NUM> provides some of the drive parameters from which the foregoing was determined.

With respect to the crossing output mode, it was determined that a pulse repetition frequency between about <NUM> and <NUM> for a duty cycle between about <NUM>% and <NUM>% can provide the longitudinal displacement of the core wire at the sufficient amplitude to effect the lesion-crossing procedures. The pulse repetition frequency becomes a smaller component in providing the longitudinal displacement of the core wire at the sufficient amplitude to effect the intravascular lesion-crossing procedures for a duty cycle of about <NUM>%. Any pulse repetition frequency including a pulse repetition frequency between about <NUM> and <NUM> for the duty cycle of about <NUM>% can provide the longitudinal displacement of the core wire at the sufficient amplitude to effect the intravascular lesion-crossing procedures. Table <NUM> provides some of the drive parameters from which the foregoing was determined.

As such, provided herein in some embodiments is a system including a console and a catheter assembly. The console includes an ultrasound-producing mechanism configured to convert an electric current into a vibrational energy. The console also includes a driving-parameter modifier configured to modify driving parameters to selectively provide one or more output modes for the vibrational energy. The catheter assembly includes a sheath including a sheath lumen and a core wire at least partially disposed within the sheath lumen. The core wire includes a proximal portion and a distal portion of the core wire, wherein the proximal portion of the core wire is coupled to the ultrasound-producing mechanism. A working length of the distal portion of the core wire beyond the sheath is configured for longitudinal, transverse, or longitudinal and transverse displacement in accordance with the one or more output modes for the vibrational energy to effect different intravascular lesion-modification procedures. In some embodiments, the driving-parameter modifier is configured to modify at least the driving parameters selected from pulse repetition frequency, duty cycle, and a combination of the pulse repetition frequency and the duty cycle to effect the different intravascular lesion-modification procedures. In some embodiments, the driving-parameter modifier is configured to modify the pulse repetition frequency between about <NUM> and <NUM> to provide transverse displacement of the core wire at a sufficient amplitude to effect atherectomy procedures. In some embodiments, the driving-parameter modifier is configured to modify the duty cycle between about <NUM>% and <NUM>% to provide longitudinal displacement of the core wire at a sufficient amplitude to effect intravascular lesion-crossing procedures.

In some embodiments, the core wire further includes a buckling section between the proximal portion and the distal portion of the core wire configured to produce transverse displacement in the working length of the core wire by buckling in accordance with the one or more output modes for the vibrational energy. In some embodiments, the catheter assembly further includes a damping mechanism about the proximal portion of the core wire configured to dampen transversely oriented vibrational energy in favor of longitudinally oriented vibrational energy about the proximal portion of the core wire. In some embodiments, the damping mechanism includes a sleeve encasing the core wire with a first radial compressive force; a gasket system encasing the sleeve with a second radial compressive force; and a washer configured to contain the gasket system within a damping-mechanism bore of the catheter assembly. In some embodiments, the catheter assembly further includes a guidewire rail including a guidewire-rail lumen externally fixed to the sheath, wherein the guidewire rail terminates about a distal sheath terminus where the guidewire rail, a guidewire disposed within the guidewire-rail lumen, or a combination of the guidewire rail and a guidewire disposed within the guidewire-rail lumen is free from any effects of transverse displacement of the working length of the core wire.

Also provided herein in some embodiments is a system including a console. The console includes an ultrasound generator, an ultrasound transducer, and a driving-parameter modifier. The ultrasound generator is configured to convert an alternating electric current into a high-frequency current. The ultrasound transducer is configured to convert the high-frequency current into a vibrational energy. The driving-parameter modifier is configured to modify driving parameters to selectively provide one or more output modes for the vibrational energy. The one or more output modes for the vibrational energy effect different intravascular lesion-modification procedures with a core wire configured for longitudinal, transverse, or longitudinal and transverse displacement at a distal end of the core wire in accordance with the one or more output modes for the vibrational energy. In some embodiments, the driving-parameter modifier is configured to modify at least the driving parameters selected from pulse repetition frequency, duty cycle, and a combination of the pulse repetition frequency and the duty cycle to effect the different intravascular lesion-modification procedures. In some embodiments, the driving-parameter modifier is configured to modify a pulse repetition frequency between about <NUM> and <NUM> to provide transverse displacement of the core wire at a sufficient amplitude to effect atherectomy procedures. In some embodiments, the driving-parameter modifier is configured to modify a duty cycle between about <NUM>% and <NUM>% to provide longitudinal displacement of the core wire at a sufficient amplitude to effect intravascular lesion-crossing procedures.

Also provided herein in some embodiments is a system including a catheter assembly. The catheter assembly includes a sheath, a core wire, and a damping mechanism. The sheath includes a sheath lumen, and the core wire is at least partially disposed within the sheath lumen. The core wire includes a proximal portion and a distal portion of the core wire, wherein the proximal portion of the core wire is coupled to an ultrasound-producing mechanism configured to selectively provide one or more output modes for a vibrational energy. The damping mechanism about the proximal portion of the core wire is configured to dampen transversely oriented vibrational energy in favor of longitudinally oriented vibration energy about the proximal portion of the core wire. A working length of the distal portion of the core wire beyond the sheath is configured for longitudinal, transverse, or longitudinal and transverse displacement in accordance with the one or more output modes for the vibrational energy to effect different intravascular lesion-modification procedures. In some embodiments, the core wire further includes a buckling section within a medial portion of the core wire between the proximal portion and the distal portion of the core wire, wherein the buckling section is configured to produce transverse displacement in the working length of the core wire by buckling in accordance with the one or more output modes for the vibrational energy. In some embodiments, the core wire further includes a tapered section and an inversely tapered section in the medial portion of the core wire, wherein the buckling section is between the tapered section and the inversely tapered section of the core wire, and wherein the buckling section is at least <NUM>" long with a cross-sectional area smaller than either one of the tapered section or the inversely tapered section. In some embodiments, the damping mechanism includes a polymeric sleeve encasing the core wire; a gasket system encasing the polymeric sleeve; and a washer configured to contain the gasket system within a damping-mechanism bore of the catheter assembly. In some embodiments, the gasket system includes a number of radially and longitudinally compressed O-rings configured to prevent irrigation backflow from the catheter assembly into the ultrasound-producing mechanism. In some embodiments, the damping mechanism is centered over a vibrational node of the core wire to minimize frictional heating caused by damping the transversely oriented vibrational energy. In some embodiments, the catheter assembly further includes a guidewire rail including a guidewire-rail lumen externally fixed to the sheath. In some embodiments, the guidewire rail terminates about a distal sheath terminus where the guidewire rail, a guidewire disposed within the guidewire-rail lumen, or a combination of the guidewire rail and a guidewire disposed within the guidewire-rail lumen is free from any effects of transverse displacement of the working length of the core wire.

While some particular embodiments have been provided herein, and while the particular embodiments have been provided in some detail, it is not the intention for the particular embodiments to limit the scope of the concepts presented herein. Additional adaptations and/or modifications can appear to those of ordinary skill in the art, and, in broader aspects, these adaptations and/or modifications are encompassed as well. Accordingly, departures may be made from the particular embodiments provided herein without departing from the scope of the concepts provided herein.

Claim 1:
A system (<NUM>), comprising:
a console (<NUM>) comprising:
an ultrasound-producing mechanism (<NUM>) configured to convert an electric current into a vibrational energy; and
a driving-parameter modifier (<NUM>) configured to modify driving parameters to selectively provide one or more output modes for the vibrational energy; and
a catheter assembly (<NUM>) comprising:
a sheath (<NUM>) comprising a sheath lumen (<NUM>); and
a core wire (<NUM>) at least partially disposed within the sheath lumen (<NUM>) comprising a proximal portion (<NUM>) and a distal portion (<NUM>) of the core wire, wherein:
the proximal portion (<NUM>) of the core wire (<NUM>) is coupled to the ultrasound-producing mechanism (<NUM>); and
a working length (<NUM>) of the distal portion (<NUM>) of the core wire beyond the sheath (<NUM>) is configured for longitudinal, transverse, or longitudinal and transverse displacement in accordance with the one or more output modes for the vibrational energy to effect different intravascular lesion-modification procedures, wherein the driving-parameter modifier (<NUM>) is configured to modify at least the driving parameters selected from pulse repetition frequency, duty cycle, and a combination of the pulse repetition frequency and the duty cycle to effect the different intravascular lesion-modification procedures.