Patent Description:
Tissue-removing catheters are used to remove unwanted tissue in body lumens. As an example, atherectomy catheters are used to remove material from a blood vessel to open the blood vessel and improve blood flow through the vessel. This process can be used to prepare lesions within a patient's coronary artery to facilitate percutaneous coronary angioplasty (PTCA) or stent delivery in patients with severely calcified coronary artery lesions. Atherectomy catheters typically employ a rotating element which is used to abrade or otherwise break up the unwanted tissue.

<CIT> describes a tissue-removing catheter with a guidewire isolation liner. <CIT> describes a clinically practical rotational angoplasty system.

The invention provides a tissue-removing catheter according to claim <NUM>. Further embodiments of the invention are provided in the dependent claims.

Referring to the drawings, and in particular <FIG>, a rotational tissue-removing catheter for removing tissue in a body lumen is generally indicated at reference number <NUM>. The illustrated catheter <NUM> is a rotational atherectomy device suitable for removing (e.g., abrading, cutting, excising, ablating, etc.) occlusive tissue (e.g., embolic tissue, plaque tissue, atheroma, thrombolytic tissue, stenotic tissue, hyperplastic tissue, neoplastic tissue, etc.) from a vessel wall (e.g., coronary arterial wall, etc.). The catheter <NUM> may be used to facilitate percutaneous coronary angioplasty (PTCA) or the subsequent delivery of a stent. Features of the disclosed embodiments may also be suitable for treating chronic total occlusion (CTO) of blood vessels, and stenoses of other body lumens and other hyperplastic and neoplastic conditions in other body lumens, such as the ureter, the biliary duct, respiratory passages, the pancreatic duct, the lymphatic duct, and the like. Neoplastic cell growth will often occur as a result of a tumor surrounding and intruding into a body lumen. Removal of such material can thus be beneficial to maintain patency of the body lumen.

The catheter <NUM> is sized for being received in a blood vessel of a subject. Thus, the catheter <NUM> may have a maximum size of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> French (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>) and may have a working length of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM> depending of the body lumen. While the remaining discussion is directed toward a catheter for removing tissue in blood vessels, it will be appreciated that the teachings of the present disclosure also apply to other types of tissue-removing catheters, including, but not limited to, catheters for penetrating and/or removing tissue from a variety of occlusive, stenotic, or hyperplastic material in a variety of body lumens.

Referring to <FIG> and <FIG>, the catheter <NUM> comprises an elongate drive coil <NUM> (broadly, an elongate body) disposed around an elongate inner liner <NUM>. The drive coil <NUM> and inner liner <NUM> extend along a longitudinal axis LA of the catheter from a proximal end portion <NUM> to a distal end portion <NUM> of the catheter. A tissue-removing element <NUM> is disposed on a distal end of the drive coil <NUM> and is configured for rotation to remove tissue from a body lumen as will be explained in greater detail below. An isolation sheath <NUM> (<FIG>) is disposed around the drive coil <NUM>. The drive coil <NUM> and the inner liner <NUM> are both configured to translate relative to the isolation sheath <NUM>. The catheter <NUM> is sized and shaped for insertion into a body lumen of a subject. The isolation sheath <NUM> isolates the body lumen from at least a portion of the drive coil <NUM> and inner liner <NUM>. The inner liner <NUM> defines a guidewire lumen <NUM> (<FIG>) for slidably receiving a guidewire <NUM> therein so that the catheter <NUM> can be advanced through the body lumen by traveling along the guidewire. The guidewire can be a standard <NUM>-inch outer diameter, <NUM> length guidewire. In certain embodiments, the inner liner <NUM> may have a lubricious inner surface for sliding over the guidewire <NUM> (e.g., a lubricious surface may be provided by a lubricious polymer layer or a lubricious coating). In the illustrated embodiment, the guidewire lumen <NUM> extends all the way through the length of the inner liner <NUM> such that the guidewire <NUM> is extendable along an entire working length of the catheter <NUM>. In one embodiment, the overall working length of the catheter <NUM> may be between about <NUM> (<NUM> inches) and about <NUM> (<NUM> inches). In use, the guidewire <NUM> may extend about <NUM> (<NUM> inches) past a distal end of the inner liner <NUM>.

Referring to <FIG> and <FIG>, the catheter <NUM> further comprises a handle <NUM> secured at a proximal end of the isolation sheath <NUM>. The handle <NUM> comprises a housing <NUM> that supports the components of the handle. The housing <NUM> has a generally elongate egg shape and includes as plurality of housing sections secured together to enclose the internal components of the handle <NUM>. In the illustrated embodiment, the housing <NUM> includes a bottom housing section 41A, a middle housing section 41B secured to the top of the bottom housing section, and a top housing section 41C secured to the top of the middle housing section. The middle housing section 41B has a generally racetrack shape, and the bottom and top housing sections 41A, 41C are generally dome shaped. The bottom housing section 41A has a flat bottom surface for resting the housing <NUM> on a support surface. A mode selector <NUM> is mounted generally between the middle housing section 41B and the top housing section 41C and defines a portion of the housing <NUM>. As will be explained in greater detail below, the mode selector <NUM> is configured to selectively place the catheter <NUM> in a plurality of modes and to lock the guide wire in place in at least one of the modes. The middle housing section 41B has recessed areas <NUM> on each side to provide a gripping area for the housing <NUM>. In one embodiment, the bottom housing section 41A is removable from the middle housing section 41B to provide access to the components of the handle <NUM> in the interior of the housing <NUM> by a user. It will be understood that the housing <NUM> can have other shapes and configurations without departing from the scope of the disclosure.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, the housing <NUM> supports an actuator <NUM> (e.g., a lever, a button, a dial, a switch, or other device) configured for selectively actuating a motor <NUM> disposed in the handle to drive rotation of the drive coil <NUM>, and a tissue-removing element <NUM> mounted at the distal end of the drive coil. The motor <NUM> is configured to rotate the drive coil <NUM> and tissue-removing element <NUM> at speeds of greater than about <NUM>,<NUM> RPM. The motor <NUM> is coupled to the drive coil <NUM> by a gear assembly <NUM> and drive assembly <NUM> supported within the housing <NUM>. The gear assembly <NUM> comprises a gearbox housing <NUM> that mounts and at least partially encloses a pair of gears for transferring the rotation of a shaft of the motor <NUM> to the drive coil <NUM>. The gearbox housing <NUM> includes a main housing section <NUM> and a front housing section <NUM>. The front housing section <NUM> is secured to the main housing section <NUM> by a plurality of fasteners <NUM>. Clips <NUM> further secures the front housing section <NUM> to the main housing section <NUM>. In one embodiment, the main housing section <NUM> and front housing section <NUM> may have a keyed engagement that locates the housing sections with respect to each other and prevents angular rotation of the housing sections relative to each other. For example, the keyed engagement may comprise a plurality of projections and recessed surfaces on each of the housing sections <NUM>, <NUM> whereby a projection on the main housing section is received at a recessed surface on the front housing section, and a projection of the front housing section is received at a recessed surface on the main housing section. To this effect, the projections on one of the housing sections <NUM>, <NUM> would be located adjacent to a projection on the other of the housing sections generally preventing one housing section from being rotated relative to the other housing section. The main housing section <NUM> incudes a sleeve portion <NUM> on a proximal side of the main housing section that receives an end of a buckle tube <NUM>. The main housing section <NUM> also attaches to a carriage or advancer frame <NUM> via fasteners <NUM> for moving the motor <NUM> and gear assembly <NUM> within the housing <NUM>. Further, attaching the gearbox housing <NUM> to the distal end of the advancer frame <NUM> secures the motor <NUM> in the advancer frame so that the motor moves along with the advancer frame. The front hosing section <NUM> has a sleeve portion <NUM> on a distal side of the front housing section that receives washers (not shown) for disposal around the drive assembly <NUM>. A driver gear <NUM> is attached to the motor shaft (not shown) such that the driver gear rotates with the motor shaft when the motor <NUM> is activated. A driven gear <NUM> (<FIG>) is in mesh with the driver gear <NUM> so that rotation of the driver gear causes the driven gear to rotate in the opposite direction. The drive assembly <NUM> attaches the driven gear <NUM> to the drive coil <NUM> so that the rotation of the driven gear causes the drive coil to rotate. A controller <NUM> may be provided in the handle <NUM>. The controller <NUM> may be programmed to control operation of the catheter.

It is understood that other suitable actuators, including but not limited to touchscreen actuators, wireless control actuators, automated actuators directed by a controller, etc., may be suitable to selectively actuate the motor in other embodiments. In some embodiments, a power supply may come from a battery (not shown) contained within the handle <NUM>. The battery can provide the current source for the guidewire detection circuit. In other embodiments, the power supply may come from an external source.

Referring to <FIG>, the drive assembly <NUM> comprises a gear insert <NUM> received in the driven gear <NUM>, a tube insert <NUM> received in the gear insert, and a lock <NUM> attached to a distal end of the tube insert. In one embodiment, the gear insert <NUM> is press fit into the driven gear <NUM>. The gear insert <NUM> comprises a cylindrical member having a uniform outer diameter extending along a length of the cylindrical member and circumferentially around the cylindrical member. An inner surface of the cylindrical member includes a plurality of circumferentially spaced channels <NUM> that extend along the length of the cylindrical member and thereby define an inner diameter of the cylindrical member that is non-uniform. The channels <NUM> extend from the distal end of the cylindrical member to an intermediate location between the distal and proximal ends of the cylindrical member. At the end of the channels <NUM> is an annular recess <NUM>. The inner surface of the cylindrical member tapers at the proximal end forming an annular shoulder <NUM> and a reduced inner diameter at the proximal end. The gear insert <NUM> may be formed from any suitable material including without limitation, stainless steel and Peek. In the illustrated embodiment, the gear insert <NUM> is formed separately from the driven gear <NUM>. However, the gear insert <NUM> could be formed integrally with the driven gear <NUM>.

The tube insert <NUM> comprises a tubular member having a reduced outer diameter proximal end margin forming a shoulder <NUM> near the proximal end of the tube insert. A plurality of circumferentially spaced projections <NUM> extend along a distal end margin of tube insert <NUM>. In the illustrated embodiment, there are four projections <NUM> each having a triangular cross-section. Another number of projections <NUM> could be used without departing from the scope of the disclosure. The projections <NUM> define circumferentially spaced gaps <NUM> between the projections. The outer diameter of the tube insert <NUM> is sized so that it can be received in the gear insert <NUM>. When the tube insert <NUM> is inserted into the gear insert <NUM> the shoulder <NUM> on the tube insert engages the shoulder <NUM> in the gear insert to provide a stop for locating the tube insert in the gear insert. This hard stop holds the tube insert <NUM> in place in the gear insert <NUM> when the drive coil <NUM> and drive assembly <NUM> are placed in compression. The tube insert <NUM> also defines a passage extending longitudinally through the tube insert and which is sized to receive the drive coil <NUM>. The drive coil <NUM> is fixedly attached to the tube insert <NUM> such as by welding. The tube insert <NUM> may be formed from any suitable material including without limitation, stainless steel. The gear insert <NUM> and tube insert <NUM> may together be broadly considered a gear extension. The gear extension may include both or only one of the gear insert <NUM> and tube insert <NUM>.

The lock <NUM> comprises a tubular portion <NUM> and a plurality of fingers <NUM> projecting from a proximal end of the tubular portion. In the illustrated embodiment, there are four fingers <NUM>. However, another number of fingers <NUM> could be used without departing from the scope of the disclosure. Each of the finger <NUM> has an elongate portion <NUM> and a hook portion <NUM> projecting laterally from the elongate portion away from a central axis of the lock <NUM>. Prior to inserting the tube insert <NUM> into the gear insert <NUM>, the lock <NUM> is engaged with the tube insert by inserting the fingers <NUM> in the gaps <NUM> in the tube insert (<FIG>). Therefore, when the tube insert <NUM> is inserted into the gear insert <NUM>, the fingers <NUM> will flex inward and ride along the channels <NUM> in the gear insert until they reach the annular recess <NUM> at the end of the channels where the fingers are then permitted to flex outward such that the hook portions <NUM> snap into the recess to secure the lock <NUM> in the gear insert. Thus, the lock <NUM> couples the drive coil <NUM> to the gear assembly <NUM> in the handle <NUM>. This configuration provides overlap of the lock <NUM> with the gear insert <NUM> and the tube insert <NUM> which facilitates a better transfer of rotation to the drive coil <NUM> and allows the drive assembly <NUM> to better withstand the torque applied to the drive assembly. The connection between the lock <NUM> and the gear insert <NUM> also holds the drive assembly <NUM> together when the drive coil <NUM> and drive assembly are placed in tension. The tubular portion <NUM> of the lock <NUM> also defines a passage sized to receive the drive coil <NUM>. The lock <NUM> may be formed from any suitable material including without limitation, stainless steel and Peek. The construction of the drive assembly <NUM> also allows the drive assembly to be connected to the gear assembly <NUM> by inserting the drive assembly through the distal end of the gear assembly. This prevents the need for access to the proximal end of the handle <NUM> or for additional parts required in the assembly of a conventional auto chuck mechanism. In the illustrated embodiment, an annular recess <NUM> is shown in the gear insert <NUM>. However, the gear insert <NUM> could include a plurality of discrete receptacles at the ends of the channels <NUM> for receiving the hook portions <NUM> of the lock <NUM>.

In one embodiment (<FIG>), the hook portion <NUM> projects from the elongate portion <NUM> such that a gear insert engagement surface <NUM> of the hook portion extends at an obtuse angle from the elongate portion. In this embodiment, the lock <NUM> may be detached from the gear insert <NUM> by applying a sufficient pulling force on the tubular portion <NUM> to withdraw the fingers <NUM> from the gear insert. During use, however, the angled face utilizes the pull force transmitted from the drive coil <NUM> through the tube insert <NUM> to the lock <NUM> to provide extra strength to the lock's snap feature to achieve the pull force requirement. In another embodiment (<FIG>), a gear insert engagement surface 115A extends orthogonally from the elongate portion 109A of finger 107A. In this embodiment, recesses 93A in the gear insert 85A may be open at the outer surface of the gear insert to allow a tool to be inserted into the receptacle to release the hook portion 111A from the receptacle. A wall 117A of the recess 93A in the gear inert 85A is configured to match the gear insert engagement surface 115A of the fingers 107A so that a sound locking connection is made between the lock 89A and the gear insert 85A. In <FIG>, a hook portion 111B has a first section <NUM> that is configured to be received in a recess 93B in the gear insert 85B, and a second section 121B configured to engage the channel 91B in the gear insert when the first section is received in the receptacle.

Further, the drive assembly <NUM> reduces the number of components for interfacing with the drive coil <NUM> to couple the handle <NUM> to the catheter body. The drive assembly <NUM> also enables assembly and disassembly of the drive assembly by only requiring access to the distal end of the gear shaft through the gearbox <NUM>. This means the handle <NUM> can be closed to protect the internal components, such as the internal electronics. Additionally, the design of the drive assembly <NUM> facilitates decoupling of the catheter body components from the handle <NUM>. Thus, the handle <NUM> can be recouple with another catheter body and/or any reworking tasks can be performed on the handle. Therefore, the handle <NUM> does not have to be discarded with the catheter body after use.

Referring to <FIG>, a sensor <NUM> may be mounted to the gearbox housing <NUM> and configured to detect rotation of the driver gear <NUM>. For example, the sensor <NUM> may emit a signal toward a surface of the driver gear <NUM> to detect the rotation of the driver gear. Gear rotation can be used to determine the operability of the motor <NUM>.

Referring to <FIG>, <FIG>, <FIG>, <FIG>, a travel sheath interface assembly <NUM> is mounted on the distal side of the front housing section <NUM> of the gearbox housing <NUM> and secures a travel sheath <NUM> in the handle <NUM>. The travel sheath interface assembly <NUM> comprises a travel sheath connector <NUM> attached to a distal end of the sleeve portion <NUM> of the front housing section <NUM> of the gearbox housing <NUM>, and a seal (e.g., o-ring) <NUM> received between the sleeve portion and the travel sheath connector. The travel sheath connector <NUM> is snap fit onto the sleeve portion <NUM> of the front housing section <NUM> of the gearbox housing <NUM>. The travel sheath connector <NUM> includes a plate portion <NUM>, an insert portion <NUM> extending proximally from a center of the plate portion, and a pair of arms <NUM> at the periphery of the plate portion that also extend proximally from the plate portion. The insert portion <NUM> defines an annular groove <NUM> that receives the seal <NUM>. Each arm <NUM> has a hook <NUM> at its free end. The arms <NUM> extends along sides of the sleeve portion <NUM>, and the hooks <NUM> clip around the side of the sleeve portion to attach the travel sheath connector <NUM> to the sleeve portion by a snap fit engagement. The hooks <NUM> project laterally inward from a longitudinal extension of the arms <NUM> such that a gearbox retention surface <NUM> of the hooks extends at about a <NUM>-degree angle to a longitudinal axis of the arm. This facilitates removal of the travel sheath connector <NUM> from the sleeve portion <NUM> with a sufficient distal puling force. A ramp surface <NUM> on each arm <NUM> extends at about a <NUM>-degree angle to the longitudinal axis of the arm to facilitate attachment of the travel sheath connector <NUM> to the sleeve portion <NUM>. The ramp surfaces <NUM> are configured ride up a first sloped surface <NUM> on the sleeve portion <NUM>. The gearbox retention surfaces <NUM> slide down a second sloped surface <NUM> on the sleeve portion to clip the travel sheath connector <NUM> onto the sleeve portion. With the travel sheath connector <NUM> attached to the sleeve portion <NUM>, the o-ring <NUM> provides a seal to the gearbox. A passage <NUM> extends through the travel sheath interface assembly <NUM> and is defined by aligned axial holes in the sleeve portion <NUM> of the front housing section <NUM> of the gearbox housing <NUM> and travel sheath connector <NUM>. The travel sheath <NUM> is fixedly received in the axial hole in the travel sheath connector <NUM> to attach the travel sheath to the travel sheath interface assembly <NUM>. The travel sheath <NUM> is sized to receive the drive coil <NUM> within an interior of the travel sheath and extends from the travel sheath interface assembly <NUM> to isolation sheath interface assembly <NUM>. The travel sheath assembly <NUM>, including the travel sheath <NUM>, aligns and stabilizes the drive coil <NUM> such that the extension of the drive coil is maintained along an axis during operation of the catheter <NUM>. The travel sheath <NUM> may be considered part of the travel sheath assembly <NUM>.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, a slide or advancer <NUM> is positioned on the handle <NUM> and is operatively coupled to the drive coil <NUM> for movement of the drive coil relative to the handle to advance and retract the drive coil and tissue-removing element <NUM>. The housing <NUM> of the handle <NUM> may define a slot <NUM> which limits the movement of the slide <NUM> relative to the handle. Thus, the length of the slot determines the amount of relative movement between the drive coil <NUM> and the handle <NUM>. In one embodiment, the slot has a length of about <NUM> (<NUM> inches). The slide <NUM> is operatively attached to the advancer frame <NUM> so that movement of the slide causes movement of the advancer frame. The advancer frame <NUM> comprises an arch shaped body including a rear section <NUM>, a middle section <NUM>, and a front section <NUM>. The rear section <NUM> include an arcuate portion <NUM> that extends from a first side of the frame <NUM> generally to an opposite second side of the frame and plate portion <NUM> having an opening <NUM> formed therein. In the illustrated embodiment, the opening <NUM> is round for receiving an end of the motor <NUM>. The middle section <NUM> includes a plurality of circumferentially spaced body portions <NUM> defining open spaces between the body portions. The front section <NUM> includes an arcuate portion <NUM> that extends from the first side of the frame <NUM> to the second side. The arch shape body of the frame <NUM> is configured to slidingly receive the cylindrically shaped motor <NUM> such that the motor extends from the front section <NUM> to the rear section <NUM> with the end of the motor held inside the opening <NUM> in the rear section. A first pair of bearings <NUM> (<FIG>) are mounted at the bottom of the rear and front sections <NUM>, <NUM>, respectively, on the first side of the frame <NUM>. The bearings <NUM> are seated on a ledge <NUM> (<FIG>) on the middle housing section 41B so that the bearings can slide along the ledge to facilitate movement of the frame <NUM> in the housing <NUM>. A second pair of bearings <NUM> (<FIG>) are mounted at the top of the second side of the frame <NUM> on the middle section <NUM> and the front section <NUM>, respectively. Arms <NUM> extend from the rear section <NUM> and middle section <NUM> and have bearings <NUM> mounted thereon. The bearings <NUM> (<FIG>) on the arms <NUM> engage an underside of the top housing section 41C to facilitate movement of the frame <NUM> in the housing <NUM>.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, the mode selector <NUM> comprises a guide portion <NUM> that is supported by the housing <NUM>, a lever <NUM> attached to the guide portion and actuatable to move the guide portion relative to the housing, and a motor switching portion <NUM> operatively connected to the guide portion for causing the motor <NUM> to change its operational state based on the position of the guide portion. In the illustrated embodiment, the guide portion <NUM> sits on a floor <NUM> of the middle housing section 41B and pivots relative to the middle housing section. Other engagements between the mode selector <NUM> and the housing <NUM> that facilitate the same or other forms of movement of the mode selector are also envisioned. In one embodiment, the lever <NUM> is actuatable to place the motor <NUM> in a "standby mode" where the motor is deactivated and the guide wire <NUM> is unlocked so that the guidewire can be moved relative to the catheter <NUM>. In one embodiment, the "standby mode" is initiated by pivoting the lever <NUM> to engage one of the stops <NUM> on the housing <NUM>. The lever <NUM> is further actuatable to place the motor <NUM> in a "track mode" where the motor is activated to produce a first output and the guide wide <NUM> is kept unlocked. The first motor output may be a reduced output which generates a pulsed output and/or a relatively slow rotation of the drive coil <NUM>. The "track mode" may be initiated when the catheter <NUM> is navigating through a particularly tortuous passage. In the illustrated embodiment, the "track mode" is initiated by pivoting the lever <NUM> to an intermediate position between the stops <NUM>. The lever <NUM> is also actuatable to place the motor <NUM> in an "abrade mode" where the motor activated to produce a second output and the guide wire <NUM> is locked relative to the catheter <NUM>. The second motor output may be an operational output which is increased over the first output so that a relatively high-speed rotation of the drive coil <NUM> is achieved. In one embodiment, the motor <NUM> produces a rotation of about <NUM>,<NUM> RPMs. The "abrade mode" may be initiated when the catheter <NUM> is operating to remove occlusive tissue from a vessel wall. In one embodiment, the "abrade mode" is initiated by pivoting the lever <NUM> to engage the other of the stops <NUM> on the housing <NUM>. Movement of the lever <NUM> to this position will also cause a locking pin <NUM> to press against the guide wire <NUM> locking the guide wire in place.

A guidewire lock <NUM> (<FIG>) may be provided in the handle <NUM> to lock the guidewire <NUM> in place relative to the handle. The guidewire lock <NUM> comprises the locking pin <NUM> retained in the middle housing section 41B and a spring <NUM> received around the locking pin. A head of the locking pin <NUM> engages an underside of the guide portion <NUM> of the mode selector <NUM>. The spring <NUM> biases the locking pin away from the guidewire <NUM>. The underside of the guide portion <NUM> includes a first section <NUM>, a ramp section <NUM> extending from the first section, and a second section <NUM> extending from the ramp section such that the second section is recessed below the first section. In the illustrated embodiment, the head of the locking pin <NUM> is positioned to be engaged by the sections <NUM>, <NUM>, <NUM> on the underside of the guide portion <NUM> as the mode selector is moved between the different positions. For example, movement of the mode selector <NUM> to a first position causes the head of the locking pin <NUM> to oppose the elevated first section <NUM> allowing the spring <NUM> to freely press against the head of the locking pin to space the shaft of the locking pin from engaging the guidewire <NUM>, thus permitting the guidewire to move relative to the catheter <NUM>. Movement of the mode selector <NUM> to a second position causes the head of the locking pin <NUM> to oppose the recessed second section <NUM> causing the guide portion <NUM> to press down on the locking pin <NUM> against the bias of the spring <NUM> moving the locking pin downward to frictionally engage the shaft with the guidewire <NUM> to lock the guidewire <NUM> in place. In one embodiment, the guidewire lock <NUM> is engages the guidewire <NUM> to lock the guidewire in place when the mode selector <NUM> is moved to place the catheter <NUM> in the abrade mode.

Referring to <FIG>, an isolation sheath interface assembly <NUM> is disposed at the distal end of the handle <NUM>. The assembly <NUM> comprises an interface housing <NUM>, a seal (e.g., o-ring) <NUM> received in a proximal end portion <NUM> of the interface housing, and a retainer <NUM> attached to the proximal end of the interface housing to retain the seal to the interface housing. The retainer <NUM> includes a plate portion <NUM> and a pair of arms <NUM> that extend distally from the plate portion. Each arm <NUM> has a hook <NUM> at its free end. The arms <NUM> extends along sides of the proximal end portion <NUM> of the interface housing <NUM> and the hooks <NUM> clip around a distal end of the proximal end portion to attach the retainer <NUM> to the interface housing by a snap fit engagement. With the retainer <NUM> attached to the interface housing <NUM>, the plate portion <NUM> engages the seal <NUM> to hold the seal in place. The interface housing <NUM> further includes a first tab <NUM> on a top of the housing that is received in a slot <NUM> in the middle section 41B of the housing <NUM>, a second tab <NUM> on a bottom of the housing and received in a slot <NUM> in the bottom section 41A of the housing, the proximal end portion <NUM>, and a distal end portion <NUM> that is disposed between the middle and bottom housing sections 41A, 41B. The engagement of the tabs <NUM>, <NUM> and the distal end portion <NUM> of the interface housing <NUM> with the housing <NUM> mounts the isolation sheath interface assembly <NUM> to the housing. The distal end portion <NUM> also extends into a passage in a hub <NUM> mounted on the proximal end of the isolation sheath <NUM> to attach the hub to the handle <NUM>. The hub <NUM> provides a strain relief function at the junction between the distal end of the housing <NUM> and the catheter components extending from the housing.

The interface housing <NUM> also defines a longitudinal passage <NUM> extending from the proximal end of the interface housing to a distal end of the interface housing. The longitudinal passage <NUM> receives the travel sheath <NUM> and drive coil <NUM> at the proximal end of the interface housing, and the drive coil extends entirely through the housing to the distal end of the housing. The seal <NUM> is also received in the longitudinal passage <NUM> and extends around the travel sheath <NUM> to provide a fluid seal against fluid traveling proximally past the seal. The longitudinal passage <NUM> also receives the isolation sheath <NUM> at the distal end of the interface housing <NUM>, and the isolation sheath extends to an intermediate location between the proximal and distal ends of the interface housing. A transverse passage <NUM> extends from the longitudinal passage <NUM> to a transverse opening <NUM> in the interface housing <NUM>. The interface housing <NUM> also defines a perfusion port <NUM> for delivering fluid (e.g. saline) between the drive coil <NUM> and the isolation sheath <NUM>. The transverse passage <NUM> extends through the perfusion port <NUM> and thus communicates the perfusion fluid to the longitudinal passage <NUM>. Therefore, the transverse passage <NUM> through port <NUM> communicates with a space between the isolation sheath <NUM> and the drive coil <NUM> for delivering the fluid to the rotating drive coil. In one embodiment, a micro pump <NUM> (<FIG> an 9A) may be connected to a fluid (e.g., saline) bag for pumping the fluid through tubing to the perfusion port. A proximal port <NUM> (<FIG>, <FIG>, and <FIG>) in the housing <NUM> allows for passage of the guidewire <NUM> through the proximal end of the handle <NUM>.

Referring to <FIG>, and <FIG>, the isolation sheath <NUM> comprises a tubular sleeve configured to isolate and protect a subject's arterial tissue within a body lumen from the rotating drive coil <NUM>. The isolation sheath <NUM> is fixed to the handle <NUM> at a proximal end of the sheath and does not rotate. The isolation sheath interface assembly <NUM> attaches the sheath to the handle <NUM>. The sheath <NUM> is received in the distal end portion <NUM> of the interface housing <NUM> to attach the sheath to the handle. The isolation sheath <NUM> provides a partial enclosure for the drive coil <NUM> and inner liner <NUM> to move within the sheath. The inner diameter of the isolation sheath <NUM> is sized to provide clearance for the drive coil <NUM>. The space between the isolation sheath <NUM> and the drive coil <NUM> allows for the drive coil to rotate within the sheath and provides an area for saline perfusion between the sheath and drive coil. The outer diameter of the isolation sheath <NUM> is sized to provide clearance with an inner diameter of a guide catheter (not shown) for delivering the catheter <NUM> to the desired location in the body lumen. In one embodiment, the isolation sheath <NUM> has an inner diameter of about <NUM> inches (<NUM>), an outer diameter of about <NUM> inches (<NUM>), and a length of about <NUM> (<NUM> inches). The isolation sheath <NUM> can have other dimensions without departing from the scope of the disclosure. In one embodiment, the isolation sheath <NUM> is made from Polytetrafluorethylene (PTFE). Alternatively, the isolation sheath <NUM> may comprise a multi-layer construction. For example, the isolation sheath <NUM> may comprise an inner layer of perfluoroalkox (PFA), a middle braided wire layer, and an outer layer of Pebax.

Referring to <FIG>, <FIG>, and <FIG>, the drive coil <NUM> may comprise a tubular stainless steel coil configured to transfer rotation and torque from the motor <NUM> to the tissue-removing element <NUM>. Configuring the drive coil <NUM> as a coiled structure provides the drive coil with a flexibility that facilitates delivery of the catheter <NUM> through the body lumen. In addition, the coil configuration allows for the rotation and torque of the drive coil <NUM> to be applied to the tissue-removing element <NUM> when the catheter <NUM> is traversed across a curved path. The stiffness of the drive coil <NUM> also impacts the ease at which the coil is traversed through the body lumen as well as the coil's ability to effectively transfer torque to the tissue-removing element <NUM>. In one embodiment, the drive coil <NUM> is relatively stiff such that axial compression and extension of the coil is minimized during movement of the catheter <NUM> through a body lumen. The coil configuration of the drive coil <NUM> is also configured to expand its inner diameter when the coil is rotated so that the drive coil remains spaced from the inner liner <NUM> during operation of the catheter <NUM>. In one embodiment, the drive coil <NUM> has an inner diameter of about <NUM> inches (<NUM>) and an outer diameter of about <NUM> inches (<NUM>). The drive coil <NUM> may have a single layer construction. For example, the drive coil may comprise a <NUM> filar (i.e., wire) coil with a lay angle of about <NUM> degrees. Alternatively, the drive coil <NUM> could be configured from multiple layers without departing from the scope of the disclosure. For example, the drive coil <NUM> may comprise a base coil layer and a jacket (e.g., Tecothane™) disposed over the base layer. In one embodiment, the drive coil comprises a <NUM> filar coil with a lay angle of about <NUM> degrees. The Tecothane™ jacket may be disposed over the coil. Alternatively, the drive coil <NUM> may comprise a dual coil layer configuration which also includes an additional jacket layer over the two coil layers. For example, the drive coil may comprise an inner coil layer comprising a <NUM> filar coil with a lay angle of about <NUM> degrees, and an outer coil layer comprising a <NUM> filar coil with a lay angle of about <NUM> degrees. Drive coils having other configurations are also envisioned.

Referring to <FIG> and <FIG>, the inner liner <NUM> comprises a multiple layer tubular body configured to isolate the guidewire <NUM> from the drive coil <NUM> and tissue-removing element <NUM>. The inner liner <NUM> is extendable through the handle <NUM> from a position within the handle to a position distal of the handle. In one embodiment, the inner liner <NUM> is coupled to the components within the handle <NUM> but is not fixedly attached to the housing <NUM> to allow translation of the inner liner relative to the housing. The inner liner <NUM> has an inner diameter that is sized to pass the guidewire <NUM>. The inner liner <NUM> protects the guide wire from being damaged by the rotation of the drive coil <NUM> by isolating the guidewire from the rotatable drive coil. The inner liner <NUM> may also extend past the tissue-removing element <NUM> to protect the guidewire <NUM> from the rotating tissue-removing element. Thus, the inner liner <NUM> is configured to prevent any contact between the guidewire <NUM> and the rotating components of the catheter <NUM>. Therefore, any metal-to-metal engagement is eliminated by the inner liner <NUM>. This isolation of the drive coil <NUM> and tissue-removing element <NUM> from the guidewire <NUM> also ensures that the rotation of the drive coil and tissue-removing element is not transferred or transmitted to the guidewire. As a result, a standard guidewire <NUM> can be used with the catheter <NUM> because the guidewire does not have to be configured to withstand the torsional effects of the rotating components. Additionally, by extending through the tissue-removing element <NUM> and past the distal end of the tissue-removing element, the inner liner <NUM> stabilizes the tissue-removing element by providing a centering axis for rotation of the tissue-removing element about the inner liner.

In the illustrated embodiment, the inner liner <NUM> comprises an inner PTFE layer <NUM> an intermediate braided layer <NUM> comprised of stainless steel, and an outer layer <NUM> of polyimide. The PTFE inner layer <NUM> provides the inner liner <NUM> with a lubricous interior which aids in the passing of the guidewire <NUM> though the inner liner. The braided stainless steel intermediate layer <NUM> provides rigidity and strength to the inner liner <NUM> so that the liner can withstand the torsional forces exerted on the inner liner by the drive coil <NUM>. In one embodiment, the intermediate layer <NUM> is formed from <NUM> stainless steel. The outer polyimide layer <NUM> provides wear resistance as well as having a lubricous quality which reduces friction between the inner liner <NUM> and the drive coil <NUM>. Additionally, a lubricious film, such as silicone, can be added to the inner liner <NUM> to reduce friction between the inner liner and the drive coil <NUM>. In one embodiment, the inner liner <NUM> has an inner diameter ID of about <NUM> inches (<NUM>), an outer diameter OD of about <NUM> inches (<NUM>), and a length of about <NUM> inches (<NUM>). The inner diameter ID of the inner liner <NUM> provides clearance for the standard <NUM>-inch guidewire <NUM>. The outer diameter OD of the inner liner <NUM> provides clearance for the drive coil <NUM> and tissue-removing element <NUM>. Having a space between the inner liner <NUM> and the drive coil <NUM> reduces friction between the two components as well as allows for saline perfusion between the components.

Referring to <FIG>, a liner key <NUM> is attached to a proximal end of the liner <NUM> and is received in a guide tube <NUM> fixedly mounted in the handle <NUM>. The liner <NUM> and liner key <NUM> may be broadly a liner assembly <NUM>. The engagement between the liner key <NUM> and the guide tube <NUM> permits the liner key and liner <NUM> to translate relative to the guide tube but prevents rotation of the liner key and liner relative to the guide tube. The liner key <NUM> comprises a semi-cylindrical member <NUM> and an elongate tubular member <NUM> extending distally from a distal end of the semi-cylindrical member. A channel <NUM> extends through the liner key <NUM>. The channel <NUM> forms an inner diameter D<NUM> in the semi-cylindrical member of about <NUM> and an inner diameter D<NUM> in the tubular member of about <NUM>. In one embodiment, the semi-cylindrical member <NUM> has a length L of between about <NUM> and about <NUM>. In one embodiment, the semi-cylindrical member <NUM> has a length L of about <NUM>. The proximal end of the liner <NUM> is received and retained in the section of the channel <NUM> in the elongate tubular member <NUM>. The liner <NUM> can be retained in the liner key <NUM> by any suitable means, including without limitation, glue, thermal bond, and mechanical bond. The proximal end of the liner <NUM> seats against a floor <NUM> in the liner key <NUM> to locate the liner in the liner key. Thus, the liner key <NUM> and the liner <NUM> co-translate with each other. In the illustrated embodiment, the guide tube <NUM> has a circular passage <NUM>. Alternatively, the guide tube <NUM> may have a non-circular interior passage defined by top and bottom curved wall sections and a pair of side planar wall sections extending between the top and bottom wall sections.

The semi-cylindrical member <NUM> comprises a pair of top and bottom curved surfaces <NUM> and a pair of opposing flat surfaces <NUM> so that the dimensions of the guide tube and liner key <NUM> prevent relative rotation. In one embodiment, a width W<NUM> extending between the flat surfaces <NUM> of the semi-cylindrical member <NUM> is about <NUM>, and height Hi extending between the top and bottom curved surfaces <NUM> is about <NUM>. In one embodiment, a dimeter D<NUM> of the interior passage of the guide tube <NUM> is about <NUM>. Alternatively, in the embodiment where the guide tube includes side planar wall sections, a width of the interior passage <NUM> of the guide tube <NUM> may be about <NUM>, and a height may be about <NUM>. Thus, the interior passage <NUM> provides sufficient clearance to receive the liner key <NUM> for axial movement but does not allow rotational movement of the liner key in the guide tube. The configuration of the liner key <NUM> and guide tube <NUM> also reduces the friction on the liner <NUM> during advancement and retraction of the liner. In one embodiment, axial translation of at least about <NUM> is permitted. The liner key <NUM> configuration also facilitates assembly of the handle <NUM> by allowing the key to be inserted though the gearbox housing <NUM>.

It is envisioned that the liner key <NUM> and guide tube <NUM> can have over configurations for permitting relative translation and preventing relative rotation. For instance, the liner key <NUM> can be generally rectangular and the guide tube <NUM> may have a mating rectangular interior passage. Still other configurations are envisioned within the scope of the disclosure. Further, any suitable materials may be used for the liner key <NUM> and guide tube <NUM>. For example, the liner key <NUM>, can be formed from Peek, Polyoxymethylene (POM), or polycarbonate (PC). The inner liner <NUM> and liner key <NUM> may be broadly considered a liner key assembly.

Referring to <FIG>, <FIG>, and <FIG>, the handle <NUM> provides four locations of contact or interface between the internal components of the handle and the longitudinally extending catheter components (broadly, catheter body assembly) that extend through the handle. A first interface <NUM> occurs between the liner assembly <NUM> and the guide tube <NUM>. A second interface <NUM> occurs between the drive coil <NUM> and the drive assembly <NUM>. A third interface <NUM> occurs between the drive coil and the travel sheath interface assembly <NUM>. A fourth interface <NUM> occurs between the isolation sheath <NUM> and the isolation sheath interface assembly <NUM>. It will be understood that the internal components of the handle <NUM> may interface with the catheter body assembly at other location.

The interfaces <NUM>, <NUM>, <NUM>, <NUM> are axially aligned along the longitudinal extension of the catheter components. The interfaces <NUM>, <NUM>, <NUM>, <NUM> provide alignment and stability to the catheter body assembly as it passes through the handle <NUM>. In particular, the first interface <NUM> between the liner key assembly <NUM> and the guide tube <NUM> aligns and stabilizes the liner <NUM>. This helps to prevent buckling of the liner <NUM> during movement of the liner <NUM> in the handle <NUM>. As a result, the extension of the liner <NUM> is maintained along a linear axis. Further, the second interface <NUM> stabilizes the drive coil <NUM> within the housing <NUM>. Thus, the extension of the drive coil <NUM> during rotation of the drive coil is maintained about a linear axis that is generally parallel to and coincident with the axis of extension of the liner <NUM>. Therefore, the spacing between the drive coil <NUM> and liner <NUM> are maintained throughout operation of the catheter <NUM> so that the liner appropriately shields the guidewire <NUM> from the rotating drive coil <NUM>. The third interface <NUM> stabilizes and holds the drive coil <NUM> in alignment throughout the extension of the drive coil through the travel sheath interface assembly <NUM>. Therefore, the linear extension of the drive coil is maintained along the distal portion of the handle <NUM>. The fourth interface <NUM> functions to stabilize the drive coil <NUM> as well as the isolation sheath <NUM> to maintain alignment of the drive coil with the inner liner <NUM> during rotation.

Referring to <FIG>, <FIG>, and <FIG>, the tissue-removing element <NUM> extends along the longitudinal axis LA from a proximal end adjacent the distal end portion of the drive coil <NUM> to an opposite distal end. The tissue-removing element <NUM> is operatively connected to the motor <NUM> for being rotated by the motor. When the catheter <NUM> is inserted into the body lumen and the motor <NUM> is rotating the tissue-removing element <NUM>, for example in the abrade mode, the tissue-removing element is configured to remove occlusive tissue in the body lumen to separate the tissue from the wall of the body lumen. Any suitable tissue-removing element for removing tissue in the body lumen as it is rotated may be used in one or more embodiments. In one embodiment, the tissue-removing element <NUM> comprises an abrasive burr configured to abrade tissue in the body lumen when the motor <NUM> rotates the abrasive burr. The abrasive burr <NUM> may have an abrasive outer surface formed, for example, by a diamond grit coating, surface etching, or the like. In one embodiment, the tissue-removing element comprises a stainless steel spheroid body with an exterior surface including <NUM> of exposed diamond crystals. The tissue-removing element <NUM> may also be radiopaque to allow the tissue-removing element to be visible under fluoroscopy. In other embodiments, the tissue-removing element can comprise one or more cutting elements having smooth or serrated cutting edges, a macerator, a thrombectomy wire, etc..

Referring to <FIG> and <FIG>, to remove tissue in the body lumen of a subject, a practitioner inserts the guidewire <NUM> into the body lumen of the subject, to a location distal of the tissue that is to be removed. Subsequently, the practitioner inserts the proximal end portion of the guidewire <NUM> through the guidewire lumen <NUM> of the inner liner <NUM> and through the handle <NUM> so that the guidewire extends through the proximal port <NUM> in the handle. With the catheter <NUM> loaded onto the guidewire <NUM>, the practitioner advances the catheter along the guidewire until the tissue-removing element <NUM> is positioned proximal and adjacent the tissue. Initially, the catheter <NUM> may be placed in the "standby" mode through actuation of the mode selector <NUM>. In this mode, the motor <NUM> is deactivated and the guide wire <NUM> is unlocked so that the catheter <NUM> can be moved relative to the guidewire. As the catheter <NUM> is being traversed through the body, the mode selector <NUM> can be moved to the "track mode" where the motor <NUM> is activated to produce the first output and the guidewire <NUM> is kept unlocked. The slow rotation of the tissue-removing element <NUM> at the first output of the motor <NUM> may be advantage in navigating the catheter <NUM> through tortuous pathways. When the tissue-removing element <NUM> is positioned proximal and adjacent the tissue, the mode selector <NUM> can be operated to place the catheter <NUM> in the "abrade mode" to operate the motor <NUM> at the second output to rotate the drive coil <NUM> and the tissue-removing element mounted on the drive coil at a higher rate for use in abrading (or otherwise removing) the tissue in the body lumen. This will also lock the guidewire <NUM> in place. While the tissue-removing element <NUM> is rotating, the practitioner may selectively move the drive coil <NUM> distally along the guidewire <NUM> to abrade the tissue and, for example, increase the size of the passage through the body lumen. The practitioner may also move the drive coil <NUM> proximally along the guidewire <NUM>, and may repetitively move the component in distal and proximal directions to obtain a back-and-forth motion of the tissue-removing element <NUM> across the tissue. During the abrading process, the inner liner <NUM> isolates the guidewire <NUM> from the rotating drive coil <NUM> and tissue-removing element <NUM> to protect the guidewire from being damaged by the rotating components. As such, the inner liner <NUM> is configured to withstand the torsional and frictional effects of the rotating drive coil <NUM> and tissue-removing element <NUM> without transferring those effects to the guidewire <NUM>. When the practitioner is finished using the catheter <NUM>, the catheter can be withdrawn from the body lumen and unloaded from the guidewire <NUM> by sliding the catheter proximally along the guidewire. The guidewire <NUM> used for the abrading process may remain in the body lumen for use in a subsequent procedure.

Referring to <FIG>, a handle of another embodiment is generally indicated at <NUM>'. The handle <NUM>' is similar to the handle <NUM> of the previous embodiment and operates generally in the same manner as handle <NUM>. For example, the handle <NUM>' also provides four points of contact or interface between the internal components of the handle and the longitudinally extending catheter body assembly <NUM> that extends through the handle. Thus, the handle <NUM>' provides alignment and stability to the catheter body assembly <NUM> as it passes through the handle <NUM>. However, the specific configuration of the internal components of the housing <NUM>'differ from the internal components of housing in some respects. The details of the internal components of the housing <NUM>' are discussed below.

Referring to <FIG>, the handle <NUM>' comprises a housing <NUM>' that supports the components of the handle and includes as plurality of housing sections secured together to enclose the internal components of the handle. A mode selector <NUM>' is mounted in the housing <NUM>' and defines a portion of the housing. As in the earlier embodiment, the mode selector <NUM>' is configured to selectively place the catheter <NUM> in a plurality of modes and lock the guide wire in place.

Referring to <FIG> and <FIG>, motor <NUM>' is coupled to the drive coil <NUM> by a gear assembly <NUM>' and drive assembly <NUM>' supported within the housing <NUM>'. The gear assembly <NUM> comprises a gearbox housing <NUM>' that mounts and at least partially encloses a pair of gears for transferring the rotation of a shaft <NUM>' of the motor <NUM>' to the drive coil <NUM>. The gearbox housing <NUM>' includes a rear housing section <NUM>' and front housing section <NUM>' formed integrally with the rear housing section such that the gearbox housing comprises a single housing structure. The rear housing section <NUM>' incudes a motor sleeve <NUM>' on a proximal side of the rear housing section that receives a distal end portion of the motor <NUM>', and a tube sleeve portion <NUM>' on the proximal side of the rear housing section that receives a distal end portion of a buckle tube <NUM>' and a distal end stop <NUM>' on guide tube <NUM>' (<FIG>). The rear housing section <NUM> also attaches to a carriage or advancer frame <NUM>' via fasteners <NUM> for moving the motor <NUM>' and gear assembly <NUM>' within the housing <NUM>'. The front housing section <NUM>' has a distal sleeve portion <NUM>' (<FIG>) that receives a portion of drive assembly <NUM>'. A driver gear <NUM>' is attached to motor shaft <NUM>' (<FIG>) such that the driver gear rotates with the motor shaft when the motor <NUM>' is activated. In one embodiment, the driver gear <NUM>' is press fit on to the motor shaft <NUM>'. A driven gear <NUM> (<FIG>) is in mesh with the driver gear <NUM> so that rotation of the driver gear causes the driven gear to rotate in the opposite direction. The drive assembly <NUM>' attaches the driven gear <NUM>' to the drive coil <NUM> so that the rotation of the driven gear causes the drive coil to rotate.

Referring to <FIG>, the drive assembly <NUM>' comprises a gear insert <NUM>' (broadly, a gear extension) extending through the driven gear <NUM>', and a lock <NUM>' received in a distal end of the gear insert. In one embodiment, the gear insert <NUM>' is press fit into the driven gear <NUM>'. Alternatively, the gear insert <NUM>' may be formed integrally with the driven gear <NUM>'. The gear insert <NUM>' has a proximal portion <NUM>' extending through the driven gear <NUM>' and proximally from the driven gear, and a distal potion <NUM>' extending distally from the driven gear. The proximal portion <NUM> comprise a cylindrical member having a uniform outer diameter extending along its length. An inner space <NUM>' (<FIG>) of the proximal portion <NUM> has a generally rectangular cross section. The distal portion <NUM>' comprise a hollow rectangular projection defining four planar sides. Openings <NUM>' in each of the sides communicate with an interior of the distal portion <NUM>'. Ramp surfaces <NUM>' on an interior side of the four sides extend from a distal end of the distal portion <NUM>' to respective axial surfaces <NUM>' in the distal portion. The openings <NUM>' extend through the axial surfaces <NUM>'. The gear insert <NUM>' may be formed from any suitable material including without limitation, stainless steel and Peek.

The lock <NUM>' comprises a base portion <NUM>', a pair of arms <NUM>' projecting from a distal end of the base portion, and fingers <NUM>' projecting laterally from a distal end of the arms. The base portion <NUM>' has a generally rectangular cross section. In the illustrated embodiment, there are two arms <NUM>' with each arm having two fingers <NUM>' extending therefrom. However, another number of arms <NUM>' and fingers <NUM>' could be used without departing from the scope of the disclosure. Each of the fingers <NUM>' has an elongate portion <NUM>' and a hook portion <NUM>' projecting laterally from the elongate portion away from a central axis of the lock <NUM>'. In the illustrated embodiment, the hook portions <NUM>' projection orthogonally from the elongate portions <NUM>'. The hook portions <NUM>' on each arm <NUM>' extend in opposite directions. Ramps <NUM>' (broadly, catches) extend laterally outward from the arms <NUM>' between the fingers <NUM>'. The lock <NUM>' may be formed from any suitable material including without limitation, stainless steel.

The base portion <NUM>' of the lock <NUM>' is inserted into the distal portion <NUM>' of the gear insert <NUM>' and into the interior space <NUM>' to secure the lock to the gear insert. As the lock <NUM>' is inserted into the gear insert <NUM>', the ramps <NUM>' on the lock will engage the ramp surfaces <NUM>' in the gear insert causing the arms <NUM>' to flex inward allowing the lock to be further inserted into the gear insert until the ramps are received in respective openings <NUM>' in the gear insert. Distal end surfaces of the ramps <NUM>' oppose edges of the openings <NUM>' preventing the lock from being pulled back out of the gear insert <NUM>'. With the lock <NUM>' fully inserted, the hook portions <NUM>' of the fingers <NUM> oppose the distal end of the gear insert <NUM>'. The engagement between the hook portions <NUM>' and the distal end of the gear insert <NUM>' holds the lock <NUM>' in place in the gear insert <NUM>' when the drive coil <NUM> and drive assembly <NUM>' are placed in compression. The connection between the ramps <NUM>' on the lock <NUM>' and the gear insert <NUM>' holds the drive assembly <NUM>' together when the drive coil <NUM> and drive assembly are placed in tension. While ramps <NUM>' are shown in the illustrated embodiment, it is envisioned that catches having other configurations could be used. For example, projections without a sloped ramp surface such as rectangular projections could be used. Still other catch configurations are envisioned within the scope of the disclosure. Bearings <NUM>' (<FIG> and <FIG>) are disposed around the proximal portion <NUM>' of the gear insert <NUM>'. The bearings <NUM>' provide additional stabilization of the rotating gear assembly <NUM>'. A projection <NUM>' (broadly, a weld feature) on a proximal end of base portion <NUM>' provides a surface for welding the lock <NUM>' to the drive coil <NUM>.

Similar to the previous embodiment, this configuration provides overlap of the lock <NUM>' with the gear insert <NUM>' which facilitates a better transfer of rotation to the drive coil <NUM> and allows the drive assembly <NUM>' to better withstand the torque applied to the drive assembly. The connection between the lock <NUM>' and the gear insert <NUM>' also holds the drive assembly <NUM>' together when the drive coil <NUM> and drive assembly are placed in tension. Further, the rectangular cross section of the interior space <NUM>' of the gear insert <NUM>' receives the rectangular base portion <NUM>' of the lock <NUM>' which is welded to the drive coil <NUM>. Thus, the engagement between the lock <NUM>' and the gear insert <NUM>' prevents relative rotation of the components which provides for a better transfer of torque from the driven gear <NUM>' to the drive coil <NUM>. In one embodiment, the lock <NUM>' is formed from stainless steel. However, other suitable materials may be used without departing from the scope of the disclosure.

Additionally, the drive assembly <NUM>' even further reduces the number of components for interfacing with the drive coil <NUM> to couple the handle <NUM>' to the catheter body. The drive assembly <NUM>' also enables assembly and disassembly of the drive assembly by only requiring access to the distal end of the gear shaft through the gearbox housing <NUM>'.

Referring to <FIG>, a liner key <NUM>' is attached to a proximal end of the liner <NUM> and is received in guide tube <NUM>' fixedly mounted in the handle <NUM>. Just as in the previous embodiment, the engagement between the liner key <NUM>' and the guide tube <NUM>' permits the liner key and liner <NUM> to translate relative to the guide tube but prevents rotation of the liner key and liner relative to the guide tube. The liner key <NUM>' comprises a rectangular member <NUM>' and an elongate tubular member <NUM>' extending distally from a distal end of the rectangular member. The proximal end of the liner <NUM> is received and retained in the elongate tubular member <NUM>'. The liner <NUM> can be retained in the liner key <NUM> by any suitable means, including without limitation, glue, thermal bond, and mechanical bond. Thus, the liner key <NUM>' and the liner <NUM> co-translate with each other. In the illustrated embodiment, the guide tube <NUM>' has a rectangular passage <NUM>' so that the dimensions of the guide tube and liner key <NUM>' prevent relative rotation. The configuration of the liner key <NUM>' and guide tube <NUM>' also reduces the friction on the liner <NUM> during advancement and retraction of the liner. Alternatively, the guide tube <NUM>' may have a generally circular interior passage. The liner key <NUM>' configuration also facilitates assembly of the handle <NUM>' by allowing the key to be inserted though the gearbox housing <NUM>'. It is envisioned that the liner key <NUM>' and guide tube <NUM>' can have other configurations for permitting relative translation and preventing relative rotation. Further, any suitable materials may be used for the liner key <NUM>' and guide tube <NUM>'. For example, the liner key <NUM>, can be formed from Peek, Polyoxymethylene (POM), or polycarbonate (PC). The inner liner <NUM> and liner key <NUM>' may be broadly considered a liner assembly <NUM>'.

Referring to <FIG>, <FIG>, and <FIG>, a guidewire port <NUM>' is mounted on a proximal end of the guide tube <NUM>'. The guidewire port <NUM>' provides structure in the handle <NUM>' to support the guidewire at the proximal end of the handle. The guidewire port <NUM>' defines an axial passage <NUM>' through which the guidewire <NUM> extends. The guidewire port <NUM>' also defines an opening <NUM>' that passes a locking pin <NUM>' of locking the guidewire in place. A flange <NUM>' on a distal end of the guidewire port <NUM>' abuts the proximal end of the guide tube <NUM>' covering at least a portion of a proximal opening of the guide tube. Thus, the flange <NUM>' prevents the liner key <NUM>' from being withdrawn from the proximal end of the guide tube <NUM>'. The passage <NUM>' through the guidewire port <NUM>' communicates an exterior of the handle <NUM>' with the interior of the guide tube <NUM>'. Thus, the guidewire port <NUM>' facilitates flushing of the liner <NUM> from the proximal end of the handle <NUM>'. In addition, the closer tolerances between the guide tube <NUM>' and the liner key <NUM>'facilitates directing flushing fluid to the liner <NUM>.

Referring to <FIG>, <FIG>, and <FIG>, the distal end stop <NUM>' is attached to a distal end of the guide tube <NUM>'. In one embodiment, the distal end stop <NUM>' is press fit onto an outer surface of the distal end of the guide tube <NUM>'. However, the distal end stop <NUM>' can be attached to the guide tube <NUM>' by any suitable means. The distal end stop <NUM>' limits the movement of the liner key <NUM>' out of the distal end of the guide tube <NUM>', and is configured to allow the liner key to enter the distal end stop at any entry angle. The distal end stop <NUM>' also centers the guide tube <NUM>' within the buckle tube <NUM>'which in turn centers and aligns the liner <NUM> within the drive coil <NUM>. Thus, the liner <NUM> is prevented from being damaged by the drive coil <NUM> rotating around the liner.

The distal end stop <NUM>' comprises an elongate member having a generally rectangular shape defining four planar side surfaces <NUM>'. The corners of the elongate member are truncated defining four angled corner surfaces <NUM>' connecting adjacent side surfaces <NUM>'. The distal end stop <NUM>' includes a proximal portion <NUM>' and a distal portion <NUM>' extending distally from the proximal portion. In the illustrated embodiment, internal ribs <NUM>' extend along an interior of the proximal portion <NUM>'. The internal ribs <NUM>' provide an engagement surface for press fitting the guide tube <NUM>' in the distal end stop <NUM>'. The proximal portion <NUM>' defines a base of the distal end stop <NUM>' and the distal portion <NUM>' comprises a plurality of extension arms extending from the base. A pair of top and bottom arms 184A' are centered at about mid-width of the distal potion <NUM>' and extend laterally along only a portion of the width of distal portion. Support extensions <NUM>' extend laterally from sides of the top and bottom arms 184A' in opposite directions to opposite sides of the distal portion <NUM>'. The support extensions <NUM>' provide structural rigidity to the top and bottom arms. A pair of side arms 184B' are centered at about mid-height of the distal portion <NUM>' and extend laterally along only a portion of the height of the distal portion. Thus, longitudinal gaps extend between the side arms 184B' and the top and bottom arms 184A'. Free ends of the arms 184A', 184B' project radially inward and together define an interior end surface <NUM>' within the distal end stop <NUM>'. The liner key <NUM>' is configured to engage the interior end surface <NUM>' when the liner <NUM> is moved distally in the handle <NUM>' preventing the liner key from moving out of the guide tube <NUM>'. Each arm 184A', 184B' also includes angled inlet surfaces <NUM>' that taper radially outward from the interior end surface <NUM>'. The angled surfaces <NUM>' provide inlet guidance at the distal end of the distal end stop <NUM>' so that during assembly the liner key <NUM>' can be inserted into the distal end of the distal end stop at any angle to secure the liner assembly <NUM>' to the guide tube <NUM>' and distal end stop. The side arms 184B' are configured to flex outwardly to provide clearance for inserting the liner key <NUM>'. Once the rectangular member <NUM>' of the liner key <NUM>' is inserted past the free ends of the side arms 184B, the arms will flex back to their natural state capturing the liner key within the distal end stop <NUM>' and preventing the liner key from being pulled back out of the distal end of the distal end stop.

External ribs <NUM>' extend longitudinally along the top and bottom of the distal end stop <NUM>'. Each external rib <NUM>' extends from the proximal portion <NUM>' to the distal portion <NUM>' along the top and bottom arms 184A, respectively. In the illustrated embodiment, the external ribs <NUM>' have a rounded outer surface. Knobs <NUM>' are disposed on the corner surfaces <NUM>' generally between the proximal and distal portions <NUM>', <NUM>'. In the illustrated embodiment, the knobs <NUM>' are domed shaped such that they also have a rounded outer surface. The knobs <NUM>' and external ribs <NUM>' provide an effective circular profile having an effective diameter that provides a close tolerance with the inner diameter of the buckle tube <NUM>' to center the distal end stop <NUM>' within the buckle tube and thereby center the liner key <NUM>' and liner <NUM> within the buckle tube. Thus, the liner <NUM> will be centered within the drive coil <NUM> preventing the liner from being damaged by the drive coil rotating around the liner. It will be understood that the distal end stop <NUM>' could have over shapes without departing from the scope of the disclosure. Additionally or alternatively, the length of the guide tube <NUM>' may be such that the movement of the liner <NUM> and liner key <NUM>' in the handle <NUM> is prevented from taking he liner key outside of the guide tube <NUM>' and/or engaging the guidewire port <NUM>' and the distal end stop <NUM>'.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, a travel sheath interface assembly <NUM>' is mounted on the distal side of the front housing section <NUM>' of the gearbox housing <NUM>' and secures a travel sheath <NUM>' in the handle <NUM>. Thus, the travel sheath interface assembly <NUM>' joins the travel sheath <NUM>' to the gearbox housing <NUM>' so that the travel sheath moves with the gearbox housing. The travel sheath interface assembly <NUM>' also provides a perfusion seal during advancement and retraction of the catheter components.

The travel sheath interface assembly <NUM>' comprises a travel sheath connector <NUM>' attached to a distal end of the distal sleeve portion <NUM>' of the front housing section <NUM>' of the gearbox housing <NUM>'. The travel sheath connector <NUM>' includes a plate portion <NUM>' and a pair of arms <NUM>' at the periphery of the plate portion that extend proximally from the plate portion. The travel sheath connector <NUM>' is snap fit onto the distal sleeve portion <NUM>' of the front housing section <NUM>' of the gearbox housing <NUM>'. This facilitates removal of the travel sheath connector <NUM>' from the distal sleeve portion <NUM>' with a sufficient distal puling force. A passage <NUM>' extends through the travel sheath interface assembly <NUM> and receives the travel sheath <NUM>'. The travel sheath <NUM>' is sized to receive the drive coil <NUM> within an interior of the travel sheath and extends from the travel sheath interface assembly <NUM>' to isolation sheath interface assembly <NUM>'. The travel sheath <NUM>' protects the drive coil <NUM> and keeps the coil axially aligned during rotation. In one embodiment, the travel sheath connector <NUM>' is overmolded on the travel sheath <NUM>.

Referring to <FIG>, <FIG>, <FIG>, <FIG>, <FIG> an isolation sheath interface assembly <NUM>' is disposed at the distal end of the handle <NUM>'. The assembly <NUM>' comprises an interface housing <NUM>', a lip seal <NUM>' received in a proximal end portion <NUM>' of the interface housing, and a retainer <NUM>' attached to the proximal end of the interface housing to retain the seal to the interface housing. The retainer <NUM>' includes a plate portion <NUM>' and a pair of arms <NUM>' that extend distally from the plate portion. Each arm <NUM>' has a hook <NUM>' at its free end. The arms <NUM>' extend along sides of the proximal end portion <NUM>' of the interface housing <NUM>' and the hooks <NUM>' clip around a distal end of the proximal end portion to attach the retainer <NUM>' to the interface housing by a snap fit engagement. The interface housing <NUM>' further includes a tab <NUM>' on a top of the housing that is received in a slot <NUM>' in the housing <NUM>'. The interface housing <NUM>' further includes a distal end portion <NUM>' that extends through the distal end of the housing <NUM>'. The engagement of the tab <NUM>' and the distal end portion <NUM>' of the interface housing <NUM>' with the housing <NUM>' of the handle <NUM>' mounts the isolation sheath interface assembly <NUM>' to the handle. The distal end portion <NUM>' also extends into a passage in a hub <NUM> mounted on the proximal end of the isolation sheath <NUM> to attach the hub to the handle <NUM>'. The engagement between the housing <NUM>' and the interface housing <NUM>' requires the interface housing to be properly seated within the housing <NUM>' of the handle <NUM>' before the housing components of the handle can be joined together.

The interface housing <NUM>' also defines a longitudinal passage <NUM>' extending from the proximal end of the interface housing to a distal end of the interface housing. The longitudinal passage <NUM>' receives the travel sheath <NUM>' and drive coil <NUM> at the proximal end of the interface housing, and the drive coil extends entirely through the housing to the distal end of the housing. The longitudinal passage <NUM>' receives the isolation sheath <NUM> at the distal end of the interface housing <NUM>', and the isolation sheath extends to an intermediate location between the proximal and distal ends of the interface housing. A transverse passage <NUM>' extends from the longitudinal passage <NUM> to a transverse opening <NUM>' in the interface housing <NUM>'. The interface housing <NUM>' also defines a perfusion port <NUM>' for delivering fluid (e.g. saline) between the drive coil <NUM> and the isolation sheath <NUM>. The transverse passage <NUM>' extends through the perfusion port <NUM> and thus communicates the perfusion fluid to the longitudinal passage <NUM>'. Therefore, the transverse passage <NUM>' through port <NUM>' communicates with a space between the isolation sheath <NUM> and the drive coil <NUM> for delivering the fluid to the rotating drive coil. In one embodiment, a micro pump <NUM>' (<FIG> and <FIG>) may be connected to a fluid (e.g., saline) bag for pumping the fluid through tubing <NUM>' to the perfusion port. In the illustrated embodiment, the sheath <NUM>, hub <NUM>, and interface housing <NUM>' are formed separately. In one embodiment, the isolation sheath <NUM>, hub <NUM>, and interface housing <NUM>' are formed as one integral unit, such as by overmolding.

When introducing elements of the present invention or the one or more embodiment(s) thereof, the articles "a", "an", "the" and "said" are intended to mean that there are one or more of the elements.

Claim 1:
A tissue-removing catheter for removing tissue in a body lumen, the tissue-removing catheter comprising:
a catheter body assembly (<NUM>) having an axis (LA) and proximal and distal end portions spaced apart from one another along the axis, at least a portion of the catheter body assembly being sized and shaped to be received in the body lumen;
a handle (<NUM>) mounted to the proximal end portion of the catheter body assembly and operable to cause rotation of the catheter body assembly, the handle including internal handle components that interface with the catheter body assembly, the internal handle components providing at least four interface locations (<NUM>, <NUM>, <NUM>, <NUM>) spaced axially along the catheter body assembly; and
a tissue-removing element (<NUM>) mounted on the distal end portion of the catheter body assembly, the tissue-removing element being configured to remove the tissue as the tissue-removing element is rotated by the catheter body assembly within the body lumen;
wherein the catheter body assembly includes an elongate body (<NUM>) sized and shaped to be received within the body lumen, an inner liner assembly (<NUM>, <NUM>') having a portion of which received within the elongate body and defining a guidewire lumen (<NUM>), and an isolation sheath (<NUM>) disposed around a section of the elongate body, the internal handle components interfacing with the inner liner assembly, elongate body, and isolation sheath of the catheter body assembly;
wherein the internal handle components interface with the liner assembly (<NUM>, <NUM>') to permit sliding movement of the liner assembly (<NUM>, <NUM>') and prevent rotational movement of the liner assembly (<NUM>, <NUM>').