Tissue removal catheter with guidewire isolation bushing

Abstract

A tissue removal catheter (10) for removing tissue in a body lumen includes an elongated body (12) and a handle (40) mounted to a proximal end portion of the elongated body (12). The handle (40) is operable to cause rotation of the elongated body (12). A tissue removal element (20) is mounted on a distal end portion of the elongated body (12). The tissue removal element (20) is configured to remove tissue as the tissue removal element (20) is rotated within the body lumen by the elongated body (12). An inner sleeve (14) is received within the elongated body (12) and is coupled to the handle (40) at a proximal end portion of the inner sleeve (14). The inner sleeve (14) defines a guidewire (26) lumen. The inner sleeve (14) is coupled to the tissue removal element (20) at a distal end portion of the inner sleeve (14) such that translational movement of the inner sleeve (14) in the body lumen causes corresponding translational movement of the tissue removal element (20).

Description

[0001] This patent application is a continuation of patent application number 202110467434.2, which is a continuation of international application number PCT / US2018 / 030965, international filing date May 3, 2018, entered into the National Stage in China as application number 201880029543.2, entitled “Tissue Removal Catheter with Guide Wire Isolation Bushing,” which claims priority to U.S. provisional application number 62 / 650, 1 1 1, filed March 30, 2018. TECHNICAL FIELD

[0002] The present disclosure relates generally to a tissue removal catheter, and more particularly, to an isolation bushing and a tissue removal element for a tissue removal catheter. BACKGROUND

[0003] Tissue removal catheters are used to remove unwanted tissue in a body lumen. 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 blood vessel. The procedure can be used to prepare a patient for percutaneous transluminal coronary angioplasty (PTCA) or stent delivery in patients with severe calcified coronary lesions. Atherectomy catheters typically employ a rotating element that is used to abrade or otherwise disrupt unwanted tissue. SUMMARY

[0004] In one aspect, a tissue removal catheter for removing tissue in a body lumen generally includes an elongated body having an axis and a proximal portion and a distal portion spaced apart from one another along the axis. The elongated body is sized and shaped to be received in the body lumen. A handle is mounted to the proximal portion of the elongated body and is operable to cause rotation of the elongated body. A tissue removal element is mounted on the distal portion of the elongated body. The tissue removal element is configured to remove tissue as the tissue removal element is rotated within the body lumen by the elongated body. An inner bushing is received within the elongated body and is coupled to the handle at a proximal portion of the inner bushing. The inner bushing defines a guide wire lumen. The inner bushing is coupled to the tissue removal element at a distal portion of the inner bushing such that translational movement of the inner bushing in the body lumen causes corresponding translational movement of the tissue removal element.

[0005] In another aspect, a tissue removal catheter for removing tissue in a body lumen generally includes an elongated body having an axis and a proximal portion and a distal portion spaced apart from one another along the axis, wherein the elongated body is sized and shaped to be received in the body lumen. A tissue removal element is mounted on the distal portion of the elongated body. The tissue removal element is configured to remove tissue as the tissue removal element is rotated within the body lumen by the elongated body. An inner liner is received within the elongated body. The inner liner defines a guidewire lumen. The inner liner is coupled to the tissue removal element at a distal portion of the inner liner such that translational movement of the inner liner in the body lumen causes corresponding translational movement of the tissue removal element.

[0006] In yet another aspect, a method of removing tissue in a body lumen generally includes advancing an elongated body and a tissue removal element mounted on a distal portion of the elongated body through the body lumen to position the tissue removal element adjacent to the tissue and to position a proximal portion of the elongated body outside of the body lumen. Advancing an inner liner disposed within the elongated body through the body lumen to position a distal portion of the inner liner adjacent to the tissue and to position a proximal portion of the inner liner outside of the body lumen. The inner liner defines a guidewire lumen. Coupling the inner liner to the tissue removal element at the distal portion of the inner liner such that translational movement of the inner liner in the body lumen causes corresponding translational movement of the tissue removal element. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 is an elevational view of the catheter of the present disclosure;

[0008] Figure 2 is an enlarged elevational view of a distal portion of the catheter;

[0009] Figure 3 is an enlarged elevational view of a proximal portion of the catheter;

[0010] Figure 4 is an enlarged partial longitudinal sectional view of the distal portion of the catheter of Figure 2

[0011] Figure 5 is a sectional view taken through line 5-5 of Figure 2

[0012] Figure 6 is a partial elevational view of the isolation liner of the catheter, with portions broken away to show internal details;

[0013] Figure 7 is an enlarged longitudinal sectional view of the tissue removal element of the catheter;

[0014] Figure 8 is a perspective view of the shaft liner of the catheter;

[0015] Figure 9 ​​is a perspective view of a first bearing of the conduit; and

[0016] Figure 10 is a perspective view of the second bearing of the catheter.

[0017] Corresponding reference characters indicate corresponding parts throughout the drawings. DETAILED DESCRIPTION

[0018] With reference to the accompanying drawings, and in particular Figure 1 A rotary tissue removal catheter for removing tissue from a body cavity is generally indicated by the reference numeral 10. The illustrated catheter 10 is an atherectomy device suitable for removing (e.g., grinding, cutting, resecting, ablating, etc.) occlusive tissue (e.g., embolic tissue, plaque tissue, atherosclerotic tissue, thrombolytic tissue, stenotic tissue, hyperplastic tissue, neoplastic tissue, etc.) from a blood vessel wall. The catheter 10 can be used to facilitate percutaneous transluminal coronary angioplasty (PTCA) or subsequent stent delivery. Features of the disclosed embodiments may also be suitable for treating chronic total occlusions (CTOs) of blood vessels, as well as stenoses of other body lumens and other hyperplastic and neoplastic diseases in other body lumens, such as the ureters, biliary tract, respiratory tract, pancreatic duct, lymphatic vessels, etc. Tumors surrounding and invading body cavities often lead to the growth of neoplastic cells. Therefore, removing such material can be beneficial in maintaining the patency of the body cavity.

[0019] The catheter 10 is sized to be received in a subject's blood vessel. Thus, the maximum dimension of the catheter 10 can be 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 the working length can be 20, 30, 40, 60, 80, 100, 120, 150, 180, or 210 centimeters, depending on the body cavity. While the remainder of the discussion is directed to catheters for removing tissue from a blood vessel, it should be understood that the teachings of the present disclosure are also applicable to other types of tissue removal catheters, including but not limited to catheters for penetrating and / or removing tissue from various occluded, stenotic, or proliferative materials in various body cavities.

[0020] Reference Figure 1 and 2The catheter 10 includes an elongated outer layer 12 disposed about an elongated inner liner 14. The outer layer 12 and the inner liner 14 extend along a longitudinal axis LA of the catheter from a proximal end portion 16 to a distal end portion 18 of the catheter. A tissue removal element 20 is disposed on the distal end of the outer layer 12 and is configured to rotate to remove tissue from a body lumen as will be described in greater detail below. A sleeve 22 is disposed about the outer layer 12. Both the outer layer 12 and the inner liner 14 are configured to translate relative to the sleeve 22. The catheter 10 is sized and shaped to be insertable into a body lumen of a subject. The sleeve 22 isolates the body lumen from at least a portion of the outer layer 12 and the inner liner 14. The inner liner 14 defines a guidewire lumen 24 Figure 5 for slidably receiving a guidewire 26 therein such that the catheter 10 can be advanced through the body lumen by tracking along the guidewire. The guidewire can be a standard 0.014 inch outer diameter, 300 cm long guidewire. In certain embodiments, the inner liner 14 can have a lubricious inner surface for sliding over the guidewire 26 (e.g., the lubricious surface can be provided by a lubricious polymer layer or a lubricious coating). In the illustrated embodiment, the guidewire lumen 24 extends from the proximal end portion 16 through the distal end portion 18 of the catheter 10 such that the guidewire 26 can extend along the entire working length of the catheter 10. In one embodiment, the overall working length of the catheter 10 can be between about 135 cm (53 inches) and about 142 cm (56 inches).

[0021] The catheter 10 also includes a handle 40 secured at the proximal end portion 16 of the catheter. The handle 40 supports an actuator 42 (e.g., a lever, a button, a dial, a switch, or other device) configured for selectively actuating a motor 43 disposed in the handle for driving the outer layer 12 and the tissue removal element 20 mounted at the distal end of the outer layer to rotate. The motor 43 is coupled to the outer layer 12 by a gear assembly 44 and a driver 48 supported by the handle 40. A slide or advancement member 45 is positioned on the handle 40 and is operably coupled to the outer layer 12 to move the outer layer relative to the handle to advance and retract the outer layer and the tissue removal element 20. The handle 40 defines a slot (not shown) that limits the movement of the slide 45 relative to the handle. Thus, the length of the slot determines the amount of relative movement between the outer layer 12 and the handle 40. An irrigation port 46 can be disposed at the proximal end 16 of the catheter 10. The port 46 communicates with the space between the sleeve 22 and the outer layer 12 for delivering fluid (e.g., saline) to cool the rotating outer layer during use. A proximal port 47 allows the guidewire 26 and the inner liner 14 to pass through the proximal end of the handle 40. A guidewire lock (not shown) can be provided on the handle 40 to lock the guidewire 26 in place relative to the handle.

[0022] It should be appreciated that in other embodiments, other suitable actuators, including but not limited to touch screen actuators, wireless control actuators, automated actuators directed by a controller, and the like, can be suitable for selectively actuating the motor. In some embodiments, the power supply can be from a battery (not shown) housed within the handle 40. In other embodiments, the power supply can be from an external source.

[0023] Referring to Figure 1 and Figure 3 The outer sleeve 22 includes a tubular sleeve configured to isolate and protect the arterial tissue within the body lumen from the rotating outer layer 12. The sleeve 22 is fixed to the handle 40 at a proximal end of the sleeve and does not rotate. An interface 52 mounted on the proximal end of the sleeve 22 attaches the sleeve to the handle 40. The interface 52 includes a locking feature 54 (e.g., a threaded luer lock) for mating with the handle 40 to attach the sleeve 22 to the handle. The sleeve 22 provides partial containment for the movement of the outer layer 12 and the inner liner 14 within the sleeve. The inner diameter of the sleeve 22 is sized to provide clearance for the outer layer 12. The space between the sleeve 22 and the outer layer 12 allows the outer layer to rotate within the sleeve and provides an area for saline irrigation between the sleeve and the outer layer. The outer diameter of the sleeve 22 is sized to provide clearance with the inner diameter of a guide catheter (not shown) used to deliver the catheter 10 to a desired location in the body lumen. A strain relief 56 is provided at the proximal end of the sleeve 22 to relieve tension applied to the proximal end of the sleeve 22 when the sleeve is bent during use of the catheter 10. In one embodiment, the sleeve 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). The sleeve 22 can have other dimensions without departing from the scope of the present disclosure. In one embodiment, the outer sleeve 22 is made of polytetrafluoroethylene (PTFE). Alternatively, the outer sleeve 22 can include a multi-layer construction. For example, the outer sleeve 22 can include an inner layer of perfluoroalkoxy (PFA), a middle layer of braided wire, and an outer layer of Pebax.

[0024] Referring to Figure 1 , 2, 4, and 5, the outer layer 12 can include a tubular stainless steel coil configured to transmit rotation and torque from the motor 43 to the tissue removal element 20. Configuring the outer layer 12 as a coiled structure provides the outer layer with flexibility that facilitates delivery of the catheter 10 through a body lumen. In addition, the coiled configuration allows rotation and torque of the outer layer 12 to be imparted to the tissue removal element 20 as the catheter 10 traverses a tortuous path. The stiffness of the outer layer 12 also affects the ease with which the coil traverses a body lumen and the ability of the coil to effectively transmit torque to the tissue removal element 20. In one embodiment, the outer layer 12 is relatively stiff such that axial compression and extension of the coil is minimized during movement of the catheter 10 through a body lumen. The coiled configuration of the outer layer 12 is also configured to expand its inner diameter as the coil rotates such that the outer layer remains spaced apart from the inner liner 14 during operation of the catheter 10. In one embodiment, the outer layer 12 has an inner diameter of about 0.023 inches (0.6 mm) and an outer diameter of 0.035 inches (0.9 mm). The outer layer 12 can have a single layer configuration. For example, the outer layer can include a 7 filament (i.e., wire) coil having a lay angle of about 30 degrees. Alternatively, the outer layer 12 can be configured from multiple layers without departing from the scope of the present disclosure. For example, the outer layer 12 can include a base coil layer and a sheath (e.g., Tecothane TM ) disposed over the base layer. In one embodiment, the outer layer includes a 15 filament coil having a lay angle of about 45 degrees. A Tecothane TM sheath can be disposed over the coil. Alternatively, the outer layer 12 can include a double coil layer configuration that also includes an additional sheath layer over the two coil layers. For example, the outer layer can include an inner coil layer including a 15 filament coil having a lay angle of about 45 degrees and an outer coil layer including a 19 filament coil having a lay angle of about 10 degrees. Outer layers having other configurations are also contemplated.

[0025] Referring to Figure 1 , 2 and 4-6, the inner liner 14 includes a multi-layer tubular body configured to isolate at least a portion of the guide wire 26 from the outer layer 12 and the tissue removal element 20. The inner liner 14 can extend from a position proximal of the handle to a position distal of the handle 40. In one embodiment, the inner liner 14 is coupled to the handle 40 but is not fixedly attached to the handle 40 to allow the inner liner to translate relative to the handle. In this embodiment, rotation of the inner liner 14 is not prohibited. However, the gap between the inner liner 14 and the outer layer 12 and the attachment of the inner liner to the coupling assembly 57 in the tissue removal element 20 prevent any rotation of the inner liner caused by rotation of the outer layer and the tissue removal element. In this embodiment, both the inner liner 14 and the outer layer 12 are allowed to translate relative to the handle 40.

[0026] The inner liner 14 has an inner diameter sized to pass the guidewire 26. The inner liner 14 protects the guidewire from damage caused by rotation of the outer layer 12 by isolating the guidewire from the rotatable outer layer. The inner liner 14 also extends past the tissue removal element 20 to protect the guidewire 26 from the rotating tissue removal element. Thus, the inner liner 14 is configured to prevent any contact between the guidewire 26 and the rotating components of the catheter 10. As a result, the inner liner 14 eliminates any metal-to-metal engagement. This isolation of the outer layer 12 and the tissue removal element 20 from the guidewire 26 also ensures that rotation of the outer layer and the tissue removal element is not transmitted or transferred to the guidewire. As a result, a standard guidewire 26 can be used with the catheter 10 because the guidewire does not have to be configured to withstand the torsional effects of the rotating components. Furthermore, by extending through the tissue removal element 20 and past the distal end of the tissue removal element, the inner liner 14 stabilizes the tissue removal element by providing a centering axis for the tissue removal element to rotate around the inner liner.

[0027] In the illustrated embodiment, the inner liner 14 includes an inner PTFE layer 60, a middle braided layer 62 comprised of stainless steel, and an outer layer 64 of polyimide. The PTFE inner layer 60 provides a lubricated interior for the inner liner 14 that facilitates the passage of the guidewire 26 through the inner liner. The braided stainless steel middle layer 62 provides rigidity and strength to the inner liner 14 so that the liner can withstand the torsional forces exerted on the inner liner by the outer layer 12. In one embodiment, the middle layer 62 is formed of 304 stainless steel. The outer polyimide layer 64 provides wear resistance and has lubricity that reduces friction between the inner liner 14 and the outer layer 12. In one embodiment, the inner liner 14 has an inner diameter ID of about 0.016 inches (0.4 millimeters), an outer diameter OD of about 0.019 inches (0.5 millimeters), and a length of about 59 inches (1500 millimeters). The inner diameter ID of the inner liner 14 provides clearance for a standard 0.014 inch guidewire 26. The outer diameter OD of the inner liner 14 provides clearance for the outer layer 12 and the tissue removal element 20. The space between the inner liner 14 and the outer layer 12 reduces friction between the two components and allows for saline irrigation between the components.

[0028] Referring to Figure 1 , 2The tissue removal element 20 extends along the longitudinal axis LA from a proximal end adjacent the distal end portion of the outer layer 12 to an opposite distal end. The tissue removal element 20 is operably connected to the motor 43 for rotation by the motor. When the catheter 10 is inserted into the body lumen and the motor 43 rotates the tissue removal element 20, the tissue removal element is configured to remove occlusive tissue in the body lumen to separate the tissue from the body lumen wall. In one or more embodiments, any suitable tissue removal element for removing tissue in a body lumen when rotated in the body lumen can be used. In the illustrated embodiment, the tissue removal element 20 comprises an abrasive burr configured to abrade tissue in the body lumen when the motor 43 rotates the abrasive burr. The abrasive burr 20 has an abrasive outer surface formed, for example, by diamond grit coating, surface etching, or the like. In other embodiments, the tissue removal element can comprise one or more cutting elements having a smooth or serrated cutting edge, an irrigator, a thrombectomy wire, or the like.

[0029] Referring to Figure 7 The cavity 72 extends longitudinally through the tissue removal element 20 such 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, forming a first shoulder 80 disposed between the first and second diameter portions. A third diameter portion 82 extends distally from the second diameter portion 78 and forms a second shoulder 84 between the second and third diameter portions. A 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 and fourth diameter portions. The diameters of the first, second, third, and fourth diameter portions 74, 78, 82, and 86 are constant along their lengths. In the illustrated embodiment, the diameter Dl 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 Dl of the first diameter portion 74 is about 0.037 inches (0.95 millimeters), the diameter D2 of the second diameter portion 78 is about 0.035 inches (0.9 millimeters), the diameter D3 of the third diameter portion 82 is about 0.033 inches (0.85 millimeters), and the diameter D4 of the fourth diameter portion 86 is about 0.031 inches (0.8 millimeters). Other cross-sectional dimensions are also contemplated without departing from the scope of the present disclosure.

[0030] Referring to Figure 4 and 7-10, the bushing 90 is received within the cavity 72 of the tissue removal element 20 and surrounds the inner sleeve 14. The bushing 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 portions of the bushing 90 define a passage 99 extending through the bushing that receives a portion of the inner sleeve 14. In the illustrated embodiment, the outer diameter of the central ring portion 92 is greater than the outer diameter of the proximal and distal ring portions 94, 96. The central ring portion 92 is configured in the second diameter portion 78 of the cavity 72, the proximal ring portion 94 is configured in the first diameter portion 74, and the distal ring portion 96 is configured in the second diameter portion 78 and the third diameter portion 82. In one embodiment, the bushing 90 is made of polyether ether ketone (PEEK) and polytetrafluoroethylene (PTFE). However, the bushing 90 can be formed of other materials without departing from the scope of the present disclosure.

[0031] A first bearing 98 is configured about the proximal ring portion 94 of the bushing 90, and a second bearing 100 is configured about the distal ring portion 96 of the bushing. 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 zirconia. The first bearing 98 is configured to align with the first diameter portion 74 of the cavity 72 in the tissue removal element 20, and is seated between the distal end of the outer layer 12 at the proximal end of the first bearing and the central ring portion 92 of the bushing 90 at the distal end of the first bearing. The second bearing 100 is configured to align with the second diameter portion 78 of the cavity 72, and is seated 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. In this manner, the bushing 90 and the bearings 98, 100 are retained within the cavity 72 of the tissue removal element 20. Generally, the bushing 90 and the bearings 98, 100 can be considered a coupling assembly 57 for coupling the inner sleeve 14 to the tissue removal element 20.

[0032] Referring to Figure 4The inner surface of the bushing 90 is fixedly attached to the inner sleeve 14 such that the inner sleeve is coupled to the tissue removal element 20 through the bushing. In one embodiment, an adhesive such as an epoxy glue bonds the bushing 90 to the inner sleeve 14. As such, the bushing 90 does not rotate about the inner sleeve 14. The outer layer 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 outer layer 12 by any suitable means. In one embodiment, an adhesive bonds the outer layer 12 to the tissue removal element 20. The outer layer 12 is received in the first diameter portion 74 of the cavity 72 and the distal end of the outer layer abuts the first bearing 98. However, the outer layer 12 is not directly attached to the bushing 90, the bearings 98 and 100, or the inner sleeve 12. Thus, rotation of the outer layer 12 and the tissue removal element 20 is not transmitted to the inner sleeve 14 to cause the inner sleeve to also rotate. Rather, the tissue removal element 20 rotates about the bushing 90 and the bearings 98, 100. And since the inner sleeve is fixedly attached to the bushing 90 that is held within the cavity 72 of the tissue removal element 20 by the outer layer 12, the inner sleeve 14 is coupled to the outer layer through the bushing and bearing arrangement. Thus, translational movement of the outer layer 12 is transmitted to the inner sleeve 14 such that the inner sleeve and the outer layer will translate together when one of the inner and outer layers is advanced or retracted within the body lumen. This construction prevents the outer layer 12 and the tissue removal element 20 from being advanced past the distal end of the inner sleeve 14 and contacting the guidewire 26. As a result, a configuration is prevented in which the inner sleeve 14 is not positioned to isolate the guidewire 26 from the outer layer 12 and the tissue removal element 20.

[0033] The inner sleeve 14 extends through the outer layer 12 and past the distal end of the tissue removal element 20. The fourth diameter portion 86 of the cavity 72 is sized to allow the inner sleeve 14 to pass with a small clearance. The inner diameter D4 provides clearance between the tissue removal element 20 and the inner sleeve 14 to reduce friction between the components. Thus, the tissue removal element 20 is shaped and arranged to extend about the inner sleeve 14 and at least a portion of the outer layer 12 and thus provides a relatively compact assembly for abrading tissue at the distal end portion of the catheter 10.

[0034] Referring to Figure 7The outer surface of the body of the tissue removal element 20 includes a proximal section 102, an intermediate section 104, and a distal section 106. The proximal section 102 increases in diameter from the proximal end of the tissue removal element 20 to the intermediate section 104. The intermediate section has a constant diameter and extends from the proximal section 102 to the distal section 106. The distal section 106 tapers in diameter from the intermediate section 104 to the distal end of the tissue removal element 20. The transition between the proximal section 102 and the intermediate section 104 forms a first angle a between the proximal section and the intermediate section. In one embodiment, the angle a is less than about 170 degrees. In one embodiment, the angle a is about 165 degrees. Similarly, the transition between the intermediate section 104 and the distal section 106 forms a second angle β between the intermediate section and the distal section. In one embodiment, the angle β is less than about 170 degrees. In one embodiment, the angle β is about 165 degrees. The tapered proximal section 102 and distal section 106 provide a generally forward and rearward wedge configuration to the tissue removal element 20 to wedge open the constricted tissue passageway as it simultaneously removes tissue through the abrasive action of the tissue removal element.

[0035] Referring to Figure 1 and Figure 2To remove tissue in a body lumen of a subject, a physician inserts the guidewire 26 into the body lumen of the subject to a location distal of the tissue to be removed. Subsequently, the physician inserts the proximal end portion of the guidewire 26 through the guidewire lumen 24 of the inner liner 14 and through the handle 40 so that the guidewire extends through the proximal port 47 in the handle. The inner liner 14 can also extend through the handle 40 and out the proximal port 47. With the catheter 10 loaded onto the guidewire 26, the physician advances the catheter along the guidewire until the tissue removal element 20 is positioned proximal of and adjacent to the tissue. When the tissue removal element 20 is positioned proximal of and adjacent to the tissue, the physician uses the actuator 42 to actuate the motor 43 to cause the outer layer 12 and the tissue removal element mounted on the outer layer to rotate. As the tissue removal element rotates, the tissue removal element 20 abrades (or otherwise removes) the tissue in the body lumen. While the tissue removal element 20 is rotating, the physician can selectively move the outer layer 12 and the inner liner 14 distally along the guidewire 26 to abrade the tissue and, for example, increase the size of the passage through the body lumen. The physician can also move the outer layer 12 and the inner liner 14 proximally along the guidewire 26 and can repeatedly move the components in the distal and proximal directions to obtain back-and-forth movement of the tissue removal element 20 over the tissue. During the abrading process, the bushing 90 and bearings 98, 100 couple the inner liner 14 to the outer layer 12 and allow the outer layer and tissue removal element to rotate about the inner liner. The inner liner 14 isolates the guidewire 26 from the rotating outer layer 12 and tissue removal element 20 to protect the guidewire from damage by the rotating components. In this manner, the inner liner 14 is configured to withstand the torsional and frictional effects of the rotating outer layer 12 and tissue removal element 20 without transmitting those effects to the guidewire 26. In addition, the coupling of the inner liner 14 and tissue removal element 20 allows movement of the inner liner, such as translational movement within the body lumen, to be transmitted to the outer layer 12 and tissue removal element so that the outer layer and tissue removal element move with the inner liner through the body lumen. When the physician has completed the procedure using the catheter 10, the catheter can be withdrawn from the body lumen and off the guidewire 26 by sliding the catheter proximally along the guidewire. The guidewire 26 used for the abrading process can remain in the body lumen for subsequent procedures.

[0036] When introducing elements of the present application or the various embodiments thereof, the articles "a", "an", "the" and "said" are intended to mean that there are one or more of the elements. The terms "comprising", "including" and "having" are intended to be inclusive and mean that there can be additional elements other than the listed elements.

[0037] As various changes could be made in the above devices, systems and methods without departing from the scope of the application, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not limiting.

Claims

1. A tissue removal catheter for removing tissue from a body cavity, the tissue removal catheter comprising: an elongated body having an axis and proximal and distal portions spaced apart from one another along the axis, wherein the elongated body is sized and shaped to be received in the body cavity; a tissue removal element mounted on the distal portion of the elongated body, the tissue removal element configured to remove the tissue when the elongated body rotates the tissue removal element within the body cavity; an inner liner received within the elongated body, the inner liner defining a guidewire lumen, the inner liner coupled to the tissue removal element at a distal end portion of the inner liner such that translational movement of the inner liner within the body cavity causes corresponding translational movement of the tissue removal element; a cavity extending through the tissue removal element from a proximal end to a distal end of the tissue removal element, wherein the cavity includes a first segment extending distally from the proximal end of the tissue removal element and a second segment extending distally from the first segment, the first segment having a cross-sectional dimension greater than a cross-sectional dimension of the second segment; It also includes a bushing, which is configured in the cavity. The bushing includes a central ring portion, a proximal ring portion extending proximally from the central ring portion, and a distal ring portion extending distally from the central ring portion. The central ring portion is configured in the second section of the cavity.

2. The tissue removal catheter according to claim 1, wherein Also included is a first bearing configured around the proximal ring portion of the bushing and a second bearing configured around the distal ring portion of the bushing, the first bearing being configured in the first section of the cavity and the second bearing being configured in the second section of the cavity.

3. The tissue removal catheter according to claim 2, wherein: The cavity includes a third section extending distally from the second section and a fourth section extending distally from the third section to the distal end of the tissue removal element, the third section having a cross-sectional dimension greater than a cross-sectional dimension of the fourth section.

4. The tissue removal catheter according to claim 3, wherein The proximal ring portion of the bushing is disposed in the first section of the cavity, and the distal ring portion of the bushing is disposed in the second and third sections of the cavity.

5. The tissue removal catheter of claim 1, wherein: The distal end of the inner sleeve extends distally of the tissue removal element.

6. The tissue removal catheter of claim 1, wherein: The inner sleeve extends distally of the bushing.

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