Tissue removal catheter with coupling liner

Abstract

A tissue removal catheter for removing tissue in a body lumen. The tissue removal catheter may include an elongate body having an axis and proximal and distal portions spaced apart from each other along the axis, the elongate body sized and shaped to be received in a body cavity; a handle mounted to the proximal end portion of the elongated body, the handle including a housing enclosing a component operable to cause rotation of the elongated body; a tissue removal element mounted on the distal end portion of the elongated body configured to remove tissue when the tissue removal element is rotated within the body cavity through the elongated body; a liner received within the elongate body and defining a guidewire lumen; and a pusher mounted on the handle and movable relative to the housing, the liner coupled at a proximal end portion thereof to the pusher such that movement of the pusher causes the liner to move accordingly to apply a pushing force to the tissue removal element to propel the tissue removal element and apply a pulling force to the tissue removal element to retract the tissue removal element, to move the tissue removal element relative to the handle.

Description

[0001] This application is a divisional application of the invention patent application with the application date of 2021-08-12, Chinese application number 202110924050.9, and titled "Tissue Removal Catheter with Coupled Liner". Technical Field

[0002] The present disclosure relates generally to a tissue removal catheter, and more particularly, to a coupling liner for a tissue removal catheter. Background Art

[0003] Tissue removal catheters are used to remove unwanted tissue from a body cavity. For example, atherectomy catheters are used to remove material from a blood vessel to open the vessel and improve blood flow in the vessel. This process can be used to prepare lesions within a patient's coronary artery to facilitate percutaneous transluminal coronary angioplasty (PTCA) or stent delivery in patients with severely calcified coronary artery lesions. Atherectomy catheters typically employ a rotating element that is used to abrade or otherwise destroy the unwanted tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figure 1 is a schematic illustration of a catheter of the present disclosure;

[0005] Figure 2 is an enlarged front view of the distal portion of the catheter;

[0006] Figure 3 It passes through Figure 2 A section taken along line 3-3 in FIG.

[0007] Figure 4 is a top perspective view of a handle of a catheter;

[0008] Figure 5 is a top perspective view of the handle with the top housing section removed;

[0009] Figure 6 is a perspective view of a gear of a gear assembly in a handle;

[0010] Fig. 7A is an exploded view of the internal components in the handle;

[0011] Figure 7B is a perspective view of a coupling sleeve in a shank;

[0012] Figure 8 is a fragmentary perspective view of a liner assembly of a catheter;

[0013] Fig. 9 is the cross section of the lining key of the lining assembly;

[0014] Fig.10is a fragmentary elevational view of an insulating liner of a catheter with portions cut away to show internal details;

[0015] Fig.11 yes Figure 2 An enlarged fragmentary longitudinal cross section of the distal portion of the catheter in;

[0016] Fig.12 is an enlarged longitudinal section of a tissue removal element of a catheter;

[0017] Fig.13 is a perspective view of a bushing of a catheter;

[0018] Fig.14 is a perspective view of a first bearing of the catheter;

[0019] Fig.15 is a perspective view of a second bearing of the catheter;

[0020] Fig.16A is a diagram of a coupling assembly of another embodiment;

[0021] Fig. 16B is a diagram of a coupling assembly of another embodiment;

[0022] Fig.17 is a schematic illustration of a coupling assembly of another embodiment;

[0023] Fig.18 is a diagram of a coupling assembly of another embodiment; and

[0024] Fig.19A -C is a diagram of a coupling assembly of another embodiment.

[0025] Corresponding reference numerals indicate corresponding parts throughout the drawings. DETAILED DESCRIPTION

[0026] With reference to the accompanying drawings, in particular Figure 1 , generally indicated by reference numeral 10, is a rotary tissue removal catheter for removing tissue in a body cavity. The catheter 10 shown is a rotary atherectomy device, which is suitable for removing (e.g., abrading, cutting, resecting, ablating, etc.) occluded tissue (e.g., embolic tissue, plaque tissue, atheromatous plaque, thrombolytic tissue, stenotic tissue, hyperplastic tissue, neoplastic tissue, etc.) from a blood vessel wall (e.g., a coronary artery wall, etc.). The catheter 10 can be used to facilitate percutaneous transluminal coronary angioplasty (PTCA) or subsequent stent delivery. The features of the disclosed embodiments can also be suitable for treating chronic total occlusion (CTO) of blood vessels and stenosis of other body cavities and other hyperplastic and neoplastic conditions in other body cavities such as ureters, bile ducts, respiratory tracts, pancreatic ducts, lymphatic vessels, etc. Neoplastic cell growth usually occurs due to tumors surrounding and invading the body cavity. Therefore, removing such substances can be beneficial to maintaining the patency of the body cavity.

[0027] The catheter 10 is sized to be received in a blood vessel of a subject. Thus, depending on the body lumen, the catheter 10 may have a maximum size of 3, 4, 5, 6, 7, 8, 9, 10, or 12 French (1, 1.3, 1.7, 2, 2.3, 2.7, 3, 3.3, or 4 mm), and may have a working length of 20, 30, 40, 60, 80, 100, 120, 150, 180, or 210 cm. Although the following discussion is directed to a catheter for removing tissue in a blood vessel, it should be understood that the teachings of the present disclosure are equally applicable to other types of tissue removal catheters, including but not limited to catheters for penetrating and / or removing tissue in various obstructive, stenotic, or hyperplastic materials in various body cavities.

[0028] refer to Figures 1 to 3 , the catheter 10 includes an elongated drive coil 12 (generally referred to as an elongated body) disposed around an elongated liner 14. The drive coil 12 and the liner 14 extend from a proximal portion 16 of the catheter to a distal portion 18 along the longitudinal axis LA of the catheter. A tissue removal element 20 is disposed on the distal end of the drive coil 12 and is configured to rotate to remove tissue from a body cavity, as will be explained in more detail below. An isolation sheath 22 is disposed around the drive coil 12. The drive coil 12 and the liner 14 are both configured to translate relative to the isolation sheath 22. The catheter 10 is sized and shaped to be inserted into a body cavity of a subject. The isolation sheath 22 isolates the body cavity from at least a portion of the drive coil 12 and the liner 14. The liner 14 defines a guidewire lumen 24 ( Figure 3 ) for receiving a guide wire 26 therein in a slidable manner so that the catheter 10 can be advanced in the body cavity by traveling along the guide wire. The guide wire can be a standard 0.014 inch outer diameter, 300 cm long guide wire. In certain embodiments, the liner 14 may have a lubricated inner surface for sliding on the guide wire 26 (for example, a lubricated surface can be provided by a lubricating polymer layer or a lubricating coating). In the illustrated embodiment, the guide wire lumen 24 extends along the entire working length of the catheter 10. In one embodiment, the total working length of the catheter 10 can be between about 135 cm (53 inches) and about 142 cm (56 inches). When in use, the guide wire 26 can extend about 40 mm (1.6 inches) beyond the distal end of the liner 14.

[0029] refer to Figure 1 and 47, the catheter 10 also includes a handle 40 fixed at the proximal end of the isolation sheath 22. The handle 40 includes a housing 41 that supports the components of the handle. The housing 41 has a generally elongated egg shape and includes a plurality of housing sections that are fixed together to enclose the internal components of the handle 40. In the illustrated embodiment, the housing 41 includes a bottom housing section 41A, an intermediate housing section 41B fixed to the top of the bottom housing section, and a top housing section 41C fixed to the top of the intermediate housing section. In one embodiment, the bottom housing section 41A can be removed from the intermediate housing section 41B to enable a user to access the components of the handle 40 that are inside the housing 41. It should be understood that the housing 41 can have other shapes and configurations without departing from the scope of the present disclosure.

[0030] The housing 41 supports an actuator 42 (e.g., a lever, button, dial, switch or other device) that is configured to selectively actuate a motor 43 disposed in the handle to drive the rotation of the drive coil 12 and the tissue removal element 20 mounted at the distal end of the drive coil. The motor 43 is configured to rotate the drive coil 12 and the tissue removal element 20 at a speed greater than about 80,000 RPM. In one embodiment, the motor 43 rotates the drive coil 12 and the tissue removal element 20 at a speed between about 10,000 and about 110,000 RPM. The motor 43 is coupled to the drive coil 12 by a gear assembly 44 and a drive assembly 48 supported in the housing 41. The gear assembly 44 includes a gearbox housing 55 that mounts and at least partially encloses a pair of gears for transmitting the rotation of the shaft of the motor 43 to the drive coil 12.

[0031] The motor 43 is coupled to the drive coil 12 via a gear assembly 44 and a drive assembly 48 supported within the housing 41. The gear assembly 44 includes a gearbox housing 55 that mounts and at least partially encloses a pair of gears for transmitting the rotation of the shaft of the motor 43 to the drive coil 12. The gearbox housing 55 includes a rear housing segment 61 and a front housing segment 63 integrally formed with the rear housing segment, so that the gearbox housing includes a single housing structure (Figure 7). The rear housing segment 61 includes a tube sleeve portion 69 on the proximal side of the rear housing segment, which receives the distal portion of the guide tube 223. The rear housing segment 61 is also attached to a bracket or pusher frame 73 for moving the motor 43 and the gear assembly 44 within the housing 41. In addition, attaching the gearbox housing 55 to the distal end of the pusher frame 73 fixes the motor 43 in the pusher frame so that the motor moves together with the pusher frame. The front housing section 63 has a distal sleeve portion that receives a portion of the drive assembly 48. The drive gear 81 is attached to the motor 43 so that when the motor 43 is activated, the drive gear rotates with the motor shaft ( Figure 6). The driven gear 83 meshes with the transmission gear 81 so that rotation of the transmission gear causes the driven gear to rotate in the opposite direction. The drive assembly 48 attaches the driven gear 83 to the drive coil 12 so that rotation of the driven gear causes the drive coil to rotate. A controller 50 may be provided in the handle 40. The controller 50 may be programmed to control the operation of the catheter.

[0032] It should be understood that in other embodiments, other suitable actuators, including but not limited to touch screen actuators, wireless control actuators, automatic actuators guided by a controller, etc., may be suitable for selectively actuating the motor. In some embodiments, the power supply may come from a battery (not shown) contained in the handle 40. The battery may provide a current source for the guidewire detection circuit. In other embodiments, the power supply may come from an external source.

[0033] refer to Figure 1 , 4 and 5, a slide or pusher 45 is positioned on the handle 40 and operatively coupled to the liner 14 to move the liner relative to the handle, thereby advancing and retracting the liner, drive coil 12, and tissue removal element 20. The housing 41 of the handle 40 may define a slot 186 that limits the movement of the slide 45 relative to the handle. Thus, the length of the slot 186 determines the amount of relative movement between the liner 14 and the handle 40. In one embodiment, the slot has a length of approximately 70 mm (2.8 inches). The slide 45 is operatively attached to the pusher frame 73 so that movement of the slide causes movement of the pusher frame. The pusher frame 73 includes an arched body that is configured to receive the cylindrical motor 43 in a sliding manner. The bearing 149 ( Figure 5 ) is mounted on the frame 73. The bearing 149 is engaged with the housing 41 so that the bearing can slide along the housing to facilitate the movement of the frame 73 in the housing.

[0034] refer to Fig. 7A , the guidewire port 47 is mounted on the proximal end of a buckle tube 71. In one embodiment, the guidewire port 47 is overmolded onto the buckle tube 71. Alternatively, the guidewire port 47 may be press-fit onto the buckle tube 71. The guidewire port 47 provides structure in the handle 40 to support a guidewire at the proximal end of the handle. The guidewire port 47 defines an axial passage 152 through which the guidewire 26 extends. In addition, a guidewire lock may be provided in the guidewire port 47 to lock the guidewire 26 in place relative to the handle. The guidewire port 47 may also facilitate flushing of the liner 14 by passing a cannula through the guidewire port and into the liner wedge to allow flushing.

[0035] The guide tube 223 extends from the gearbox housing 55 at the distal end of the guide tube to the coupling sleeve 122 at the proximal end of the guide tube. The guide tube 223 is fixedly attached to the gearbox housing 55, and the coupling sleeve 122 is fixedly attached to the guide tube 223. In one embodiment, the coupling sleeve 122 is press-fitted onto the outer surface of the proximal end of the guide tube 223. However, the coupling sleeve 122 can be attached to the guide tube 223 by any suitable means. The coupling sleeve 122 is received in the locking tube 71 in a movably manner. The engagement between the coupling sleeve 122 and the locking tube 71 allows the coupling sleeve and the guide tube 223 to translate relative to the locking tube but prevents the coupling sleeve and the guide tube 223 from rotating relative to the locking tube. Specifically, the internal channel in the locking tube 71 provides enough clearance to receive the coupling sleeve 122 for axial movement, but does not allow the coupling sleeve to rotate in the locking tube. In one embodiment, an axial translation of at least about 70 mm is allowed.

[0036] refer to Figures 7A to 9 , a liner wedge 221 is attached to the proximal end of the liner 14 and received in the coupling sleeve 122, thereby securing the liner wedge to the coupling sleeve. The liner wedge 221 may be secured to the coupling sleeve by any suitable means, including but not limited to rotational locking, snap fit, friction fit, or press / glue / heat engagement. Thus, movement of the coupling sleeve 122 in the locker tube 71 causes corresponding movement of the liner wedge 221. The liner wedge 221 may also facilitate flushing of the liner 14. The liner 14 extends distally from the liner wedge 221 through the guide tube 223. The liner 14 and the liner wedge 221 may be generally referred to as a liner assembly 224. In the illustrated embodiment, the liner wedge 221 includes a locking member 225 and an elongated extension member 227 extending distally from the distal end of the locking member. A passage 229 extends through the liner wedge 221. The proximal end of the liner 14 is attached to the extension member 227 to secure the liner to the liner wedge 221. Thus, the liner wedge 221 and the liner 14 move together as a single unit. In one embodiment, the liner 14 is received in a portion of the passage 229 extending through the extension member 227. The liner 14 can be retained in the liner wedge 221 by any suitable means, including but not limited to glue, thermal bonding, and mechanical bonding. In the illustrated embodiment, the locking member 225 includes a cubic structure that includes four flat surfaces 241. However, the locking member 225 may have other shapes without departing from the scope of the present disclosure. In one embodiment, the locking member 225 has a non-circular or non-rounded outer shape. It is contemplated that the liner wedge 221, the guide tube 223, and the locking tube 71 may have other configurations to permit relative translation and prevent relative rotation. In addition, any suitable material may be used for the liner wedge 221, the guide tube 223, and the locking tube 71. For example, the liner wedge 221 may be formed of polyetheretherketone (PEEK), polyoxymethylene (POM), or polycarbonate (PC).

[0037] To assemble the liner assembly 224 in the catheter 10, the liner assembly is inserted into the proximal end 231 of the coupling sleeve 122 to secure the liner assembly to the coupling sleeve. Specifically, the liner 14 is first inserted into the proximal opening 233 of the coupling sleeve 122 and pulled through the distal opening of the coupling sleeve until the liner wedge 221 is positioned adjacent to the proximal opening. As will be explained in more detail below, the coupling sleeve 122 receives the liner wedge 221 within the coupling sleeve by a snap-fit ​​engagement to limit the movement of the liner wedge relative to the coupling sleeve. In addition, the coupling sleeve 122 is configured to allow the liner wedge 221 to enter the coupling sleeve at any entry angle and to center the guide tube 223 within the locking tube 71, which in turn centers and aligns the liner 14 within the drive coil 12. Therefore, the liner 14 is prevented from being damaged by the drive coil 12 rotating around the liner.

[0038] In the illustrated embodiment, the coupling sleeve 122 includes an elongated member of a generally rectangular shape having side surfaces 174 defining four planes. The corners of the elongated member are truncated, thereby defining four angled corner surfaces 176 connecting adjacent side surfaces 174. The coupling sleeve 122 includes a proximal portion 178 and a distal portion 180 extending distally from the proximal portion. In the illustrated embodiment, a lock segment 182 defines the distal portion 180 of the coupling sleeve 122. The lock segment 182 defines a wedge opening 183 at the proximal end of the lock segment and a wedge channel 185 extending through the lock segment from the proximal end of the lock segment to the distal end of the lock segment. The wedge opening 183 is configured to receive the wedge 221 into the wedge channel 185 when the liner assembly 224 is inserted into the coupling sleeve 122. The arm 184 extends radially and axially from the proximal base segment 187, together defining a proximal stop surface within the coupling sleeve 122. When the liner wedge 221 is inserted into the proximal opening 233 of the coupling sleeve 122, the liner wedge engages the arm 184, causing the arm to deflect outward to provide clearance for the liner wedge and thereby permit the wedge to move past the arm. After the liner wedge 221 is fully inserted into the coupling sleeve 122 such that the entire liner wedge is positioned distally of the arm 184, the arm moves back to its natural state, thereby preventing the liner wedge from being pulled back out of the proximal end of the sleeve. The length of the locking member 225 of the liner wedge 221 is such that the distal end of the locking member engages the proximal end of the guide tube 223, thereby locking the wedge in place within the sleeve 122. The angled entry surface 194 is located at the proximal end of the coupling sleeve 122 and tapers radially inward from the side surface 174. The angled surface 194 provides an entry guide at the proximal end of the coupling sleeve 122 so that during assembly, the liner wedge 221 can be inserted into the proximal end of the coupling sleeve at any angle to secure the liner assembly 224 to the coupling sleeve.

[0039] The first external rib 196A extends longitudinally along the top and bottom of the coupling sleeve 122, and the second external rib 196B extends longitudinally along the side of the sleeve. Each external rib 196A, 196B extends generally from the proximal end 231 of the coupling sleeve 122. In the illustrated embodiment, the external ribs 196A, 196B have a rounded outer surface. The external ribs 196A, 196B provide an effective circular profile for the coupling sleeve 122 having an effective diameter that provides a close tolerance to the inner diameter of the locking tube 71 to center the sleeve within the locking tube and thereby center the liner wedge 221 and the liner 14 within the locking tube. As a result, the liner 14 will be centered within the drive coil 12, thereby preventing the liner from being damaged by the drive coil rotating around the liner. It should be understood that the coupling sleeve 122 may have other shapes without departing from the scope of the present disclosure. For example, in general terms, the coupling sleeve may have a non-circular or non-rounded outer shape. Furthermore, the coupling sleeve 122 , the guide tube 223 , the gearbox housing 55 , and the thruster frame 73 may be generally referred to as a coupling assembly for coupling the liner assembly 224 including the liner 14 to the thruster 45 .

[0040] refer to Fig.16A and 16B , an alternative embodiment of a coupling assembly is shown. In this embodiment, the coupling sleeve 222, 222' is directly attached to the gearbox housing 155, 155'. In the illustrated embodiment, the coupling sleeve 222, 222' is formed integrally with the gearbox housing 155, 155'. However, the coupling sleeve 222, 222' may be formed separately from the gearbox housing 155, 155' and appropriately attached to the gearbox housing. For example, the coupling sleeve 222, 222' may include an adapter portion for attaching the coupling sleeve to the gearbox housing 155, 155'. Therefore, the coupling sleeve 222, 222' extends directly from the gearbox housing 155, 155', and the guide tube 323, 323' extends proximally from the coupling sleeve. In addition, the coupling sleeve 222, 222' does not contain external ribs. In practice, the outer dimensions of the coupling sleeves 222, 222' are sized for the tight tolerances of the interior of the locking tubes 171, 171'. In addition, the sleeves 222, 222' may define proximal and distal stop surfaces to prevent axial movement of a liner wedge received in the sleeve. The coupling assembly otherwise functions substantially the same as the coupling assembly of the previous embodiment.

[0041] refer to Fig.17, another alternative embodiment of a coupling assembly is shown. In this embodiment, the liner wedge 421 includes arms 384 that extend transversely across the wedge and are configured for snap-fit ​​engagement with the coupling sleeve 322. Thus, when the liner wedge 421 is inserted into the coupling sleeve 322, the arms 384 bend inwardly to provide clearance for the insertion of the wedge. After the arms are placed into alignment with the side openings 385 in the coupling sleeve 322, the arms 384 bend back to their natural state and remain in the side openings, thereby limiting movement of the wedge 421 relative to the coupling sleeve. The coupling assembly otherwise functions substantially the same as the coupling assembly of the previous embodiment.

[0042] refer to Fig.18 , another alternative embodiment of a coupling assembly is shown. In this embodiment, one or more magnets 435 are mounted on the coupling sleeve 422 and are configured to be attached to the liner wedge 521 for securing the liner wedge and the liner 314 to the coupling sleeve 422. In one embodiment, the liner wedge 521 is formed of a metal structure so that the liner wedge is attracted to the magnets 435 on the coupling sleeve 422. The coupling assembly otherwise functions substantially the same as the coupling assembly of the previous embodiment.

[0043] refer to Fig.19A -C, shows another alternative embodiment of the coupling assembly. In this embodiment, the coupling sleeve 522 is integrally formed with the guide tube 623. In one embodiment, the coupling sleeve 522 and the guide tube 623 are injection molded together as a unitary structure. However, the components may be formed in other ways without departing from the scope of the present disclosure. In addition, the coupling sleeve 522 includes an arm 584, which is configured to snap-fit ​​with the liner wedge 621. Therefore, when the liner wedge 621 is inserted into the coupling sleeve 522, the arm 584 bends outward to provide clearance for the insertion of the wedge. After the arm 584 is placed in alignment with the recess 585 in the coupling sleeve 522, the arm 584 bends back to its natural state and remains in the recess, thereby limiting the movement of the wedge 621 relative to the coupling sleeve. The coupling assembly otherwise functions substantially the same as the coupling assembly of the previous embodiment.

[0044] Additionally or alternatively, the arms of the coupling sleeve may engage the liner wedge by a friction fit.Other configurations for locking the liner wedge to the coupling sleeve / guide tube are also contemplated without departing from the scope of the present disclosure.

[0045] refer to Figure 1 and 3, the isolation sheath 22 includes a tubular sleeve configured to isolate and protect the arterial tissue in the body cavity of the subject from being damaged by the rotating drive coil 12. The isolation sheath 22 is fixed to the handle 40 at the proximal end of the sheath and does not rotate. The isolation sheath 22 provides a partial closure for the drive coil 12 and the liner 14 to move within the sheath. The inner diameter size of the isolation sheath 22 is set to provide a gap for the drive coil 12. The space between the isolation sheath 22 and the drive coil 12 allows the drive coil to rotate within the sheath and provides an area for saline perfusion between the sheath and the drive coil. The outer diameter size of the isolation sheath 22 is set to provide a gap in combination with the inner diameter of the guide catheter (not shown) used to deliver the catheter 10 to the desired position in the body cavity. In one embodiment, the isolation sheath 22 has an inner diameter of about 0.050 inches (1.27 mm), an outer diameter of about 0.055 inches (1.4 mm), and a length of about 1500 mm (59 inches). Without departing from the scope of the present disclosure, the isolation sheath 22 may have other dimensions. In one embodiment, the isolation sheath 22 is made of polytetrafluoroethylene (PTFE). Alternatively, the isolation sheath 22 may include a multi-layer construction. For example, the isolation sheath 22 may include an inner layer of perfluoroalkox (PFA), an intermediate braided wire layer, and an outer layer of Pebax.

[0046] refer to Figures 1 to 3 , the drive coil 12 may include a tubular stainless steel coil that is configured to transfer rotation and torque from the motor 43 to the tissue removal element 20. Configuring the drive coil 12 as a wound structure allows rotation and torque of the drive coil 12 to be applied to the tissue removal element 20 when the catheter 10 passes through a curved path. The coil configuration of the drive coil 12 is also configured to expand its inner diameter when the coil rotates, so that the drive coil remains spaced apart from the liner 14 during operation of the catheter 10. In one embodiment, the drive coil 12 has an inner diameter of approximately 0.023 inches (0.6 mm) and an outer diameter of approximately 0.035 inches (0.9 mm). The drive coil 12 may have a single-layer construction. For example, the drive coil may include a 7-filament (i.e., wire) coil having a twist angle of approximately 30 degrees. Alternatively, without departing from the scope of the present disclosure, the drive coil 12 may be configured of multiple layers. For example, the drive coil 12 may include a base coil layer and a sheath (e.g., Tecothane) disposed on the base layer. TM In one embodiment, the drive coil comprises a 15-filament coil having a lay angle of approximately 45 degrees. TMThe sheath may be disposed over the coil. Alternatively, the drive coil 12 may include a dual coil layer configuration that also includes an additional sheath layer over the two coil layers. For example, the drive coil may include an inner coil layer including a 15-filament coil with a lay angle of approximately 45 degrees and an outer coil layer including a 19-filament coil with a lay angle of approximately 10 degrees. Drive coils having other configurations are also contemplated.

[0047] refer to Figures 1 to 3 and 10, the liner 14 includes a multi-layer tubular body configured to isolate the guide wire 26 from the drive coil 12 and the tissue removal element 20. The liner 14 can extend from a position within the handle through the handle 40 to a position distal to the handle. In one embodiment, the liner 14 is coupled to a component within the handle 40 but is not fixedly attached to the housing 41 to allow the liner to translate relative to the housing. The liner 14 has an inner diameter sized to allow the guide wire 26 to pass through. The liner 14 protects the guide wire from damage due to the rotation of the drive coil 12 by isolating the guide wire from the rotatable drive coil. The liner 14 can also extend through the tissue removal element 20 to protect the guide wire 26 from the rotating tissue removal element. Therefore, the liner 14 is configured to prevent any contact between the guide wire 26 and the rotating components of the catheter 10. Therefore, the liner 14 eliminates any metal-to-metal bonding. This isolation of the drive coil 12 and tissue removal element 20 from the guide wire 26 also ensures that rotation of the drive coil and tissue removal element is not transferred or transmitted to the guide wire. Therefore, a standard guide wire 26 can be used with the catheter 10 because the guide wire does not have to be configured to withstand the torsional effects of the rotating components. In addition, by extending the liner 14 through the tissue removal element 20 and past the distal end of the tissue removal element, the liner stabilizes the tissue removal element by providing a centering axis for the rotation of the tissue removal element about the liner.

[0048] In the illustrated embodiment, the liner 14 includes an inner PTFE layer 60, a middle braided layer 62 composed of stainless steel, and a polyimide outer layer 64 ( Fig.10). The PTFE inner layer 60 provides a lubricated interior for the liner 14, which helps the guide wire 26 pass through the liner. The braided stainless steel middle layer 62 provides rigidity and strength to the liner 14 so that the liner can withstand the torsional forces applied to the liner by the drive coil 12. In one embodiment, the middle layer 62 is formed of 304 stainless steel. The polyimide outer layer 64 provides wear resistance and has lubricating properties that reduce friction between the liner 14 and the drive coil 12. In addition, a lubricating film, such as silicone, may be added to the liner 14 to reduce friction between the liner and the drive coil 12. In one embodiment, the liner 14 has an inner diameter ID of approximately 0.016 inches (0.4 mm), an outer diameter OD of approximately 0.019 inches (0.5 mm), and a length of approximately 59 inches (1500 mm). The inner diameter ID of the liner 14 provides clearance for a standard 0.014 inch guide wire 26. The outer diameter OD of the liner 14 provides clearance for the drive coil 12 and the tissue removal element 20. Having a space between the liner 14 and the drive coil 12 reduces friction between the two components and allows for perfusion of saline between the components.

[0049] refer to Figure 1 , 2 and 11, the tissue removal element 20 extends from the proximal end of the distal portion adjacent to the drive coil 12 to the opposite distal end along the longitudinal axis LA. The tissue removal element 20 is operably connected to the motor 43 to be rotated by the motor. When the catheter 10 is inserted into the body cavity and the motor 43 rotates the tissue removal element 20, the tissue removal element is configured to remove the occluded tissue in the body cavity to separate the tissue from the body cavity wall. In one or more embodiments, any suitable tissue removal element can be used to remove tissue in the body cavity when it rotates. In the illustrated embodiment, the tissue removal element 20 includes an abrasive file, which is configured to wear the tissue in the body cavity when the motor 43 rotates the abrasive file. The abrasive file 20 has an abrasive outer surface formed, for example, by diamond grit coating, surface etching, etc. In other embodiments, the tissue removal element may include one or more cutting elements, impregnators, thrombectomy wires, etc., having smooth or serrated cutting edges.

[0050] refer to Fig.12, the cavity 72 extends longitudinally through the tissue removal element 20 so that the tissue removal element defines openings at its proximal and distal ends. The cavity 72 includes a first diameter portion 74 extending distally from the proximal end of the tissue removal element 20 and a second diameter portion 78 extending distally from the first diameter portion, thereby forming a first shoulder 80 disposed between the first diameter portion and the second diameter portion. The third diameter portion 82 extends distally from the second diameter portion 78 and forms a second shoulder 84 between the second diameter portion and the third diameter portion. The fourth diameter portion 86 extends distally from the third diameter portion to the distal end of the tissue removal element and forms a third shoulder 88 between the third diameter portion and the fourth diameter portion. The diameters of the first diameter portion 74, the second diameter portion 78, the third diameter portion 82, and the fourth diameter portion 86 are constant along their lengths. In the illustrated embodiment, the diameter D1 of the first diameter portion 74 is greater than the diameter D2 of the second diameter portion 78, the diameter D2 is greater than the diameter D3 of the third diameter portion 82, and the diameter D3 is greater than the diameter D4 of the fourth diameter portion 86. In one embodiment, the diameter D1 of the first diameter portion 74 is approximately 0.037 inches (0.95 mm), the diameter D2 of the second diameter portion 78 is approximately 0.035 inches (0.9 mm), the diameter D3 of the third diameter portion 82 is approximately 0.033 inches (0.85 mm), and the diameter D4 of the fourth diameter portion 86 is approximately 0.031 inches (0.8 mm). Other cross-sectional dimensions are also contemplated without departing from the scope of the present disclosure.

[0051] The liner 14 extends through the drive coil 12 and past the distal end of the tissue removal element 20. The fourth diameter portion 86 of the lumen 72 is sized to allow the liner 14 to pass through with a small gap. The inner diameter D4 provides a gap between the tissue removal element 20 and the liner 14 to reduce friction between the components. Thus, the tissue removal element 20 is shaped and arranged to extend around at least a portion of the drive coil 12 and the liner 14 and thus provide a relatively compact assembly for abrading tissue at the distal portion of the catheter 10.

[0052] refer to Figures 11 to 13, the sleeve 90 is received in the cavity 72 of the tissue removal element 20 and surrounds the liner 14. The sleeve 90 includes a central ring portion 92, a proximal ring portion 94 extending proximally from the central ring portion, and a distal ring portion 96 extending distally from the central ring portion. The ring portion of the sleeve 90 defines a passage 99 extending through the sleeve, which receives a portion of the liner 14. In the illustrated embodiment, the central ring portion 92 has a larger outer diameter than the proximal ring portion 94 and the distal ring portion 96. The central ring portion 92 is disposed in the second diameter portion 78 of the cavity 72, the proximal ring portion 94 is disposed in the first diameter portion 74, and the distal ring portion 96 is disposed in the second diameter portion 78 and the third diameter portion 82. In one embodiment, the sleeve 90 is made of polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE). However, the sleeve 90 may be formed of other materials without departing from the scope of the present disclosure.

[0053] refer to Fig.11 , 14 15, a first bearing 98 is disposed around the proximal ring portion 94 of the bearing 90, and a second bearing 100 is disposed around the distal ring portion 96 of the bearing. The outer diameter D5 of the first bearing 98 is greater than the outer diameter D6 of the second bearing 100. In one embodiment, the bearings 98, 100 are made of zirconium oxide. The first bearing 98 is disposed to align with the first diameter portion 74 of the cavity 72 in the tissue removal element 20, and is located between the distal end of the drive coil 12 at the proximal end of the first bearing and the central ring portion 92 and the first shoulder 80 of the bushing 90 at the distal end of the first bearing. The second bearing 100 is disposed to align with the second diameter portion 78 of the cavity 72, and is located between the second shoulder 84 at the distal end of the second bearing and the central ring portion 92 of the bushing 90 at the proximal end of the second bearing. Thus, the bushing 90 and the bearings 98, 100 are retained within the cavity 72 of the tissue removal element 20. In summary, the bushing 90 and the bearings 98, 100 can be regarded as a coupling assembly 57 for coupling the liner 14 to the tissue removal element 20.

[0054] refer to Fig.11, the inner surface of the sleeve 90 is fixedly attached to the liner 14 so that the liner is coupled to the tissue removal element 20 through the sleeve. In one embodiment, an adhesive such as epoxy glue bonds the sleeve 90 to the liner 14. Therefore, the sleeve 90 does not rotate around the liner 14. The drive coil 12 is directly and fixedly attached to the tissue removal element 20. The tissue removal element 20 can be fixedly attached to the distal end of the drive coil 12 by any suitable means. In one embodiment, an adhesive bonds the drive coil 12 to the tissue removal element 20. The drive coil 12 is received in the first diameter portion 74 of the cavity 72, and the distal end of the drive coil abuts the first bearing 98. However, the liner 14 is not directly attached to the tissue removal element 20, and the drive coil 12 is not directly attached to the sleeve 90, the bearings 98, 100 or the liner. Therefore, the rotation of the drive coil 12 and the tissue removal element 20 is not transmitted to the liner 14 to also rotate the liner. In fact, the tissue removal element 20 rotates around the sleeve 90 and the bearings 98, 100. And, because the liner is fixedly attached to the hub 90, which is retained within the lumen 72 of the tissue removal element 20 by the drive coil 12, the liner 14 is coupled to the drive coil and tissue removal element through the hub and bearing arrangement.

[0055] In addition, refer to Figure 5 and 7A Attaching the guide tube 223 to the gearbox housing 55 in a fixed manner and attaching the gearbox housing to the distal end of the pusher frame 73 couples the liner assembly 224 to the pusher frame so that the liner assembly moves together with the pusher frame. Therefore, when the pusher 45 moves relative to the handle 40, the liner 14, rather than the drive coil 12, provides the main thrust and pull to the tissue removal element 20. Therefore, the movement of the pusher 45 causes direct translational movement of the liner 14, which is then transmitted to the drive coil 12 and the tissue removal element 20. This configuration utilizes the structure of the liner 14 to transmit the thrust and pull to the distal end of the catheter 10. The stiffness of the liner 14 is particularly suitable for effectively transmitting the push and pull forces to the tissue removal element 20 without experiencing the force transmission and friction losses that may occur when using the rotating drive coil 12 to provide thrust and pull. Therefore, a direct 1:1 coupling of the pusher 45 to the tissue removal element 20 is achieved. This also allows for the use of a more flexible drive coil 12 , as the drive coil is not used to transmit movement of the pusher 45 to the distal end of the catheter 10 .

[0056] refer to Figure 1 and 2In order to remove tissue in the object's body cavity, the practitioner inserts the guide wire 26 into the object's body cavity to reach the distal position of the tissue to be removed. Subsequently, the practitioner inserts the proximal portion of the guide wire 26 through the guide wire lumen 24 of the liner 14 and through the handle 40, so that the guide wire extends through the proximal port 47 in the handle. As the catheter 10 is loaded onto the guide wire 26, the practitioner advances the catheter along the guide wire until the tissue removal element 20 is positioned proximal to the tissue and adjacent to the tissue. When the tissue removal element 20 is positioned proximal to the tissue and adjacent to the tissue, the practitioner uses the actuator 42 to actuate the motor 43 to rotate the drive coil 12 and the tissue removal element mounted on the drive coil. The tissue removal element 20 wears (or otherwise removes) tissue in the body cavity when it rotates. When the tissue removal element 20 rotates, the practitioner can selectively move the drive coil 12 and the liner 14 distally along the guide wire 26 to wear the tissue and, for example, increase the size of the passage through the body cavity. The practitioner can also move the drive coil 12 and the liner 14 proximally along the guide wire 26, and can repeatedly move the components in the distal and proximal directions to achieve the forward and backward movement of the tissue removal element 20 across the tissue by sliding the pusher 45 back and forth in the slot 186 in the handle 40. Because the coupling between the pusher 45 and the tissue removal element 20 for transmitting the force from the pusher to the tissue removal element is performed by the relatively hard liner 14, the practitioner is able to have a greater degree of control over the movement of the tissue removal element 20. Therefore, there is no lost motion between the movement of the pusher 45 and the corresponding movement of the tissue removal element 20. During the grinding process, the bushing 90 and the bearings 98, 100 couple the liner 14 to the tissue removal element 20 and allow the drive coil 12 and the tissue removal element to rotate around the liner. The liner 14 also isolates the guide wire 26 from the rotating drive coil 12 and the tissue removal element 20 to protect the guide wire from being damaged by the rotating components. Thus, the liner 14 is configured to withstand the torsional and frictional effects of the rotating drive coil 12 and tissue removal element 20 without transmitting these effects to the guidewire 26. In addition, the coupling of the liner 14 and the tissue removal element 20 allows movement of the liner, such as translational movement within the body cavity, to be transmitted to the drive coil 12 and the tissue removal element so that the drive coil and the tissue removal element move with the liner through the body cavity. When the practitioner has completed using the catheter 10, the catheter can be withdrawn from the body cavity and unloaded from the guidewire 26 by sliding the catheter proximally along the guidewire. The guidewire 26 used for the abrasion process can remain in the body cavity for subsequent procedures.

[0057] When introducing elements of the present invention or one or more embodiments thereof, the articles "a," "an," and "the" are intended to indicate that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0058] As various changes could be made in the above-described apparatus, systems and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted in an illustrative and not in a limiting sense.

Claims

1. A tissue removal catheter for removing tissue in a body cavity, the tissue removal catheter comprising: an elongated body having an axis and proximal and distal portions spaced from one another along the axis, wherein the elongated body is sized and shaped to be received in the body cavity; a handle mounted to the proximal portion of the elongated body, the handle comprising a housing enclosing components operable to cause rotation of the elongated body; a tissue removal element mounted on the distal portion of the elongated body, the tissue removal element being configured to remove the tissue when the tissue removal element is rotated within the body cavity by the elongated body; a liner received within the elongated body and defining a guidewire lumen; as well as A pusher is mounted on the handle and is movable relative to the housing, and the liner is coupled to the pusher at a proximal portion of the liner so that movement of the pusher causes corresponding movement of the liner, thereby applying a pushing force on the tissue removal element to advance the tissue removal element and applying a pulling force on the tissue removal element to retract the tissue removal element to move the tissue removal element relative to the handle.

2. The tissue removal catheter of claim 1 further comprising a coupling assembly in the handle that couples the liner to the pusher.

3. The tissue removal catheter of claim 2, wherein the liner is coupled to the tissue removal element at a distal portion of the liner.

4. The tissue removal catheter of claim 3, further comprising a liner assembly comprising the liner and a wedge fixedly attached to a proximal end of the liner, wherein the coupling assembly is directly attached to the wedge.

5. The tissue removal catheter of claim 4, wherein the coupling assembly comprises a coupling sleeve fixedly attached to the wedge.

6. The tissue removal catheter of claim 5, wherein the coupling assembly comprises a guide tube attached to a distal portion of the coupling sleeve.

7. The tissue removal catheter of claim 6 further comprising a motor in the handle and operatively engaged with the elongated body for driving rotation of the elongated body and a tissue removal element mounted thereon.

8. The tissue removal catheter of claim 7, further comprising a gearbox housing at least partially enclosing a gear assembly operably connected to the motor.

9. The tissue removal catheter of claim 8, wherein a proximal end of the guide tube is attached to the coupling sleeve and a distal end of the guide tube is attached to the gearbox housing.

10. The tissue removal catheter of claim 9, wherein the guide tube is fixedly attached to the gearbox housing.

Images