Tissue removal catheter incorporating a turbine

Abstract

A tissue removal catheter for removing tissue from a body cavity includes an elongate body having an axis and a proximal portion and a distal portion spaced apart from each other along the axis. A turbine is secured to the elongate body and is positioned intermediate the proximal portion and the distal portion of the elongate body. A rotatable tissue removal element is located at the distal portion of the elongate body and is operatively coupled to the turbine such that the turbine rotates the tissue removal element. The tissue removal element removes the tissue from the body cavity as the tissue removal element is rotated by the turbine.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 808,088, filed on February 20, 2019, the entire content of which is hereby incorporated by reference. Field of the Invention

[0003] The present disclosure relates to tissue removal catheters, and more particularly to turbines that rotate tissue removal elements of tissue removal catheters. Background of the Invention

[0004] Tissue removal catheters are used to remove unwanted tissue from body cavities. As an example, atherectomy catheters are used to remove material from blood vessels to open the vessels and improve blood flow through the vessels. Some atherectomy catheters employ a rotating element that is used to abrade or otherwise fragment the unwanted tissue. Summary of the Invention

[0005] In one aspect, a tissue removal catheter for removing tissue from a body cavity includes an elongate body having an axis and a proximal portion and a distal portion spaced apart from each other along the axis. The elongate body is sized and shaped to be received within the body cavity. A turbine is secured to the elongate body and is positioned intermediate the proximal portion and the distal portion of the elongate body. A tissue removal element is mounted on the distal portion of the elongate body and is operatively coupled to the turbine. The tissue removal element is configured to remove the tissue from the body cavity as the tissue removal element rotates about the axis by the turbine.

[0006] In another aspect, a method of removing tissue from a body cavity includes advancing an elongate body through the body cavity to position a distal portion of the elongate body adjacent the tissue and a proximal portion of the elongate body outside the body cavity. An actuator outside the body cavity delivers a propellant flow to a turbine positioned intermediate the proximal portion and the distal portion of the elongate body to rotate a tissue removal element about a longitudinal axis of the elongate body to remove the tissue. The actuator outside the body cavity controls a flow rate of the propellant to the turbine to control a rotational speed and / or torque of the tissue removal element.

[0007] Other objects and features of the present disclosure will be in part apparent and in part pointed out hereinafter. Brief Description of the Drawings

[0008] Figure 1 is a schematic view of a catheter including a cross-section of one embodiment of a turbine of the present disclosure;

[0009] Figure 2 is Figure 1 a perspective view of a turbine, in which portions thereof are transparent to show internal components;

[0010] Figure 3 is a cross - section taken longitudinally through Figure 2 the turbine;

[0011] Figure 3A is a cross - section taken through line 3A - 3A in Figure 3 ;

[0012] Figure 4 is Figure 2 a front elevation view of an impeller of a turbine;

[0013] Figure 5 is a block diagram of an embodiment of a conduit without a vacuum applied to the turbine;

[0014] Figure 6 is a block diagram of another embodiment of a conduit with a vacuum applied to the turbine;

[0015] Figure 7 is a perspective view of another embodiment of the turbine of the present disclosure;

[0016] Figure 8 is Figure 7 a perspective view of a turbine, in which portions thereof are transparent to show internal components;

[0017] Figure 9 is Figure 7 a perspective view of a turbine in which the outer housing is removed to show internal components;

[0018] Figure 10 is Figure 7 a perspective cross - section of a turbine;

[0019] Figure 11 is Figure 7 a cross - section of a turbine;

[0020] Figure 12 is Figure 7 an enlarged perspective view of the proximal end of a turbine;

[0021] Figure 13 is Figure 7 a longitudinal section of a turbine;

[0022] Figure 14 is a front elevation view of an embodiment of the distal portion of a conduit of the present disclosure;

[0023] Figure 15 is Figure 14An enlarged front view of the distal portion of the catheter;

[0024] Figure 16 is Figure 15 An enlarged partial longitudinal cross-section of the distal portion of the catheter;

[0025] Figure 17 is a cross-section taken through line 17-17 in Figure 15 ;

[0026] Figure 18 is Figure 14 A partial front view of the inner lining of the catheter, with a portion cut away to show internal details;

[0027] Figure 19 is Figure 14 An enlarged front view of the distal portion of the catheter, showing a non-damaging tip on the inner lining;

[0028] Figure 20 is Figure 14 An enlarged front view of the distal portion of the catheter, showing a tapered tip on the inner lining; and

[0029] Figure 21 is Figure 14 An enlarged longitudinal cross-section of the tissue removal element of the catheter.

[0030] Corresponding reference numerals indicate corresponding components throughout the figures. DETAILED DESCRIPTION

[0031] Referring to the drawings, and specifically Figure 1 , a rotatable tissue removal catheter for removing tissue from a body cavity is generally designated by the reference numeral 10. The catheter 10 shown is a rotatable atherectomy device adapted to remove (e.g., abrade, cut, excise, ablate, etc.) occlusive tissue (e.g., embolic tissue, plaque tissue, atherosclerosis, thrombolytic tissue, stenotic tissue, hyperplastic tissue, neoplastic tissue, etc.) from a vessel wall (e.g., coronary artery wall, etc.). The catheter 10 can be used to facilitate subsequent delivery of a percutaneous transluminal coronary angioplasty (PTCA) or a stent. The features of the disclosed embodiments can also be suitable for treating chronic total occlusions (CTOs) of blood vessels as well as stenosis of other body cavities and other hyperplastic and neoplastic conditions of other body cavities (such as ureters, bile ducts, respiratory tracts, pancreatic ducts, lymphatic ducts, etc.). Neoplastic cell growth typically occurs as a result of tumors that surround and invade a body cavity. Thus, removal of this material can be beneficial in maintaining the patency of the body cavity.

[0032] The size of the catheter 10 is sized to be received within a blood vessel of a subject. Accordingly, depending on the body cavity, the maximum size 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 cm. Although the remainder of the discussion is directed to a catheter for removing tissue from a blood vessel, it should be understood that the teachings of the present disclosure also apply to other types of tissue removal catheters, including but not limited to catheters for penetrating various obstructive, stenotic or hyperplastic materials in various body cavities and / or removing tissue from said various body cavities.

[0033] Reference Figures 1 - 3 and 14, the catheter 10 includes an elongate body 12 having a longitudinal axis LA and proximal and distal portions 14 and 16 spaced along the axis, respectively. The catheter 10 includes one embodiment of a turbine generally designated 118. In the illustrated embodiment, the turbine is disposed at an intermediate location along the catheter body 12. In this embodiment, the turbine 118 divides the elongate body 12 into a distal portion (e.g., distal body portion) 12a and a proximal portion (e.g., proximal body portion) 12b, the distal portion extending distally from the turbine to the distal portion 16 of the catheter 10, the proximal portion extending proximally from the turbine to the proximal portion of the catheter. The distal body portion 12a is sized and shaped to be inserted into a body cavity of a subject. The turbine 118 can also be sized and shaped to be inserted into a body cavity. The distal body portion 12a defines a guidewire lumen 20 for slidably receiving a guidewire 22 therein such that the catheter 10 can be advanced through the body cavity by advancing along the guidewire. The guidewire lumen 20 extends distally from the turbine 118 to the distal portion 16 of the catheter 10. In some embodiments, the distal body portion 12a can have a lubricious inner surface for sliding on the guidewire 22 (e.g., the lubricious surface can be provided by a lubricious polymer layer or lubricious coating). A tissue removal element 24 is disposed at the distal end of the distal body portion 12a and is configured to rotate to remove tissue from the body cavity. As explained in more detail below, the tissue removal element 24 is operatively connected to the turbine 118, such as by a drive shaft 26, for selective rotation about the longitudinal axis LA of the catheter 10 by the turbine. In one example, the guidewire lumen 20 extends longitudinally through the drive shaft 26. When the distal body portion 12a of the catheter 10 is inserted into a body cavity and the turbine 118 rotates the tissue removal element 24, the tissue removal element removes occlusive tissue in the body cavity by separating the occlusive tissue from the wall of the body cavity.

[0034] Reference Figure 1 and 2, the turbine 118 defines a guidewire port 120, which may also define a portion of the guidewire lumen 20 (e.g., the guidewire port may define the proximal end of the guidewire lumen). The guidewire port 120 provides an exit location for the guidewire 22 at an intermediate location on the catheter 10. The guidewire 22 may be a standard 0.014-inch (0.4 mm) outer diameter guidewire. The illustrated turbine 118 allows a shorter guidewire 22 to be used with the catheter 10 because the guidewire exits the catheter at an intermediate location on the catheter rather than extending along the entire working length of the catheter. In one embodiment, a guidewire 22 having a length less than about 200 cm (about 79 inches) may be used with the catheter 10. In one embodiment, a guidewire 22 having a length between about 150 cm (59 inches) and about 190 cm (75 inches) may be used. In the illustrated embodiment, the guidewire lumen 20 extends from the turbine 118 through the distal portion 16 of the catheter 10 such that the guidewire 22 can only extend along a portion of the working length of the catheter 10. In one embodiment, the total working length of the catheter 10 may be between about 135 cm (53 inches) and about 142 cm (56 inches). In use, the guidewire 22 may extend beyond the guidewire portion 120 by about 40 mm (1.6 inches).

[0035] Reference Figure 14 , the distal body portion 12a of the illustrated catheter 10 includes an elongate liner 28, a drive shaft 26, and a sheath 30. The liner 28 at least partially defines a guidewire lumen 20 that extends through the drive shaft 26. The drive shaft 26 is configured to rotate about the liner 28, although the liner may rotate with the drive shaft. The sheath 30 is disposed about the drive shaft 26 and isolates the body cavity from at least a portion of the drive shaft 26 and the liner 28. The sheath 30, drive shaft 26, and liner 28 extend distally from the turbine 118. As explained in more detail below, rotation of the drive shaft 26 of the turbine 118 causes the tissue removal element 24 to rotate. In the illustrated embodiment, the tissue removal element 24 includes abrasive burrs. In other embodiments, the tissue removal element may include a rotatable cutter (e.g., a cutter having an annular cutting edge) or other types of tissue removal elements.

[0036] Reference Figures 1 - 4, a first embodiment of the turbine 118 includes a housing (e.g., stator), generally designated 122, that encloses a rotor 124 configured to rotate within the housing. The rotor 124 is operatively connected to the tissue removal element 24 such that rotation of the rotor within the housing 122 drives rotation of the tissue removal element. In one embodiment, the turbine 118 is configured to rotate the tissue removal element 24 at a speed greater than about 80,000 RPM while generating a torque of about 1.5 mNm. In one embodiment, the turbine 118 is a microturbine sized and arranged to be received within a body cavity of a subject. In one embodiment, the outer diameter of the turbine 118 is from about 0.5 mm to about 4 mm. The turbine 118 is sized such that it can be received within a guide catheter (not shown). In one embodiment, the turbine 118 is sized such that the catheter 10 can be received within a guide catheter having a diameter of 7F (about 2 mm) or less. In another embodiment, the turbine 118 is sized such that the catheter 10 can be received within a guide catheter having a diameter of 6F (about 1.8 mm) or less. The turbine 118 is cannulated such that the turbine is a through-hole turbine. In this manner, the turbine 118 defines a portion of the guidewire lumen 20 that extends along the drive axis DA of the turbine ( Figure 3 ). The portion of the guidewire lumen 20 defined by the turbine 118 is aligned with the portion of the guidewire lumen defined by the inner liner 28 of the distal body portion 12a (e.g., the drive axis DA is coaxial with the longitudinal axis LA of the catheter 10) such that the guidewire 22 can extend from the distal body portion into the turbine or vice versa without bending, kinking, or changing direction ( Figure 1 ).

[0037] Reference Figure 2 and 3, the housing 122 includes a distal wall 130, an outer cylindrical wall 132 extending proximally from the distal wall, a partition wall 134 at the proximal end of the outer wall, and a conical wall 136 extending proximally from the proximal end of the outer wall to the tip 138 of the conical wall. The outer wall 132 defines a rotor chamber 140 in which the rotor 124 is disposed and rotates. The conical wall 136 defines an outlet chamber 142 into which the propellant (e.g., compressed gas) enters after moving through the rotor chamber 140, as discussed in more detail below. The partition wall 134 separates the rotor chamber 140 from the outlet chamber 142. The conical wall 136 defines a guide wire port 120. A cylindrical lumen wall 144 aligned with the drive axis DA extends proximally from the partition wall 134 through the outlet chamber 142 to the guide wire port 120 on the conical wall 136 and defines a portion of the guide wire lumen 20. The partition wall 134 defines a central opening aligned with the drive axis DA to allow the guide wire 22 to extend through the partition wall between the rotor chamber 140 and the outlet chamber 142. The turbine 118 includes a bearing 146 that is mounted distally of the distal wall 130 and aligned with the drive axis DA. The bearing 146 is preferably sized such that the outer diameter of the bearing is aligned (e.g., the same) with the outer diameter of the outer wall 132. In one embodiment, the bearing 146 is sized 2 mm.

[0038] The housing 122 includes an intermediate cylindrical wall 160 that extends distally from the partition wall 134 into the rotor chamber 140 to reach a distal end that is proximally spaced from the distal wall 130. The intermediate cylindrical wall 160 divides the rotor chamber 140 into generally three segments: an outer passage 162, a transition segment 164, and an inner passage 166. The intermediate wall 160 is adjacent to the outer wall 132 but disposed radially inward of the outer wall. The outer wall 132 and the intermediate wall 160 together define a narrow outer passage 162. As explained in more detail below, the propellant (as Figure 3 shown by the red arrow) enters the rotor chamber 140 through the outer passage 162 and flows distally through the outer passage to the transition segment 164. The transition segment 164 is defined by the distal wall 130 and the distal end of the intermediate wall 160. As explained in more detail below, the transition segment 164 is configured to redirect the propellant flow (as Figure 3 shown by the red arrow) from the outer passage 162 into the inner passage 166. As Figure 3 shown, the distal wall 130 has a generally U-shaped proximal surface in cross-section that redirects the propellant flow from the distal direction to the proximal direction and into the inner passage 166. In other words, the distal wall 130 defines an annular U-shaped groove in the rotor chamber 140 and circumferentially surrounds a portion of the rotor 124. The intermediate wall 160 and the rotor 124 define the inner passage 166. As explained in more detail below, in the propellant (as Figure 3When the propellant flows proximally through the inner passageway 166 (as shown by the blue arrow in FIG. 0) and into the outlet chamber 142, the propellant causes the rotor 124 to rotate. The partition wall 134 defines at least one (preferably, a plurality of) inlet openings 168 and at least one (preferably, a plurality of) outlet openings 170. The at least one inlet opening is configured to allow the propellant to flow into the outer passageway 162, and the at least one outlet opening is configured to allow the propellant to flow out of the inner passageway 166 and into the outlet chamber 142.

[0039] The rotor 124 is disposed within the rotor chamber 140 and is configured to rotate therein. The rotor 124 includes a cylindrical drive shaft 150 that extends distally from the partition wall 134 through the rotor chamber 140 through the distal wall 130 and to the bearing 146. In one embodiment, the drive shaft extends distally through the bearing 146. The drive shaft 150 is aligned with the drive axis DA and defines a portion of the guidewire lumen 20 (e.g., the drive shaft has a bore therethrough). The cylindrical drive shaft 150 has an intermediate portion with a first diameter and proximal and distal portions with a second diameter that is less than the first diameter. The proximal portion of the drive shaft 150 is rotatably disposed within a cylindrical bearing wall 152 that extends distally from the partition wall 134 (e.g., is supported by the cylindrical bearing wall). The inner diameter of the bearing wall 152 is greater than the outer diameter of the proximal portion of the drive shaft 150 such that the drive shaft can rotate therein (e.g., provides a clearance that allows the drive shaft to rotate about the drive axis DA within the bearing wall). Preferably, the outer diameter of the bearing wall 152 is the same as the outer diameter of the intermediate portion of the drive shaft 150. The distal portion of the drive shaft 150 extends distally through an opening (aligned with the drive axis DA) in the distal wall 130 and is fixed to the bearing 146. The bearing 146 supports the drive shaft 150 and allows the drive shaft to rotate within the housing 122. The diameter of the opening in the distal wall 134 is greater than the outer diameter of the distal portion of the drive shaft 150 to provide the necessary clearance to allow the drive shaft to rotate therein.

[0040] The rotor 124 includes at least one impeller 154 that is fixed to the drive shaft 150 and extends radially outward therefrom (e.g., away from the drive axis DA) into the inner passageway 166. The inner diameter of the intermediate wall 160 is greater than the outer diameter of the impeller 154 to provide the necessary clearance to allow the impeller and thus the drive shaft 150 to rotate within the inner passageway. In the illustrated embodiment, the rotor 124 includes two impellers 154 that are longitudinally spaced apart along the drive shaft 150, but the rotor may have more or fewer impellers. The impellers 154 are connected to the intermediate portion of the drive shaft 150. As Figure 4As shown, each impeller 154 has an annular ring 156 that connects the impeller to the drive shaft 150 and a plurality of vanes 158 that extend radially outward from the ring. Each vane 158 is angled relative to the plane of rotation (e.g., a plane orthogonal to the drive axis DA) in which the impeller 154 rotates. In the illustrated embodiment, the impeller 154 has ten vanes 158 that are circumferentially spaced apart on the annular ring 156. It should be understood that the impeller 154 may have more or fewer vanes 158.

[0041] The rotor 124 is operatively connected (e.g., attached) to the drive shaft 26 of the distal body portion 12a to drive the rotation of the tissue removal element 24. As explained in more detail below, the drive shaft 26 of the distal body portion 12a is configured to rotate and is connected to the tissue removal element 24 such that rotation of the drive shaft causes the tissue removal element to rotate. In one embodiment, the proximal portion of the drive shaft 26 extends along the drive shaft 150 and is fixed to the drive shaft by any suitable means, such as but not limited to an adhesive. In other embodiments, the drive shaft 26 may be mechanically fastened to the drive shaft 150. In one embodiment, the distal portion of the drive shaft 150 includes a seat (not shown) that receives the proximal portion of the drive shaft 26. The proximal portion of the drive shaft 26 is fixed within the seat to attach the drive shaft to the drive shaft 150.

[0042] In one embodiment, the turbine 118 includes flexible proximal and distal portions (not shown) that extend proximally and distally from the proximal and distal ends of the housing 122, respectively, to provide a strain relief function for the turbine 118 by reducing the tension applied to the turbine when the catheter 10 is bent (e.g., manipulated) during use. The housing 122 may be formed of polyether ether ketone (PEEK). The impeller 154 may be formed of a metal sheet and bent into shape. For example, the impeller 154 may be laser cut from a stainless steel sheet and bent into shape.

[0043] Reference Figure 1 、 5And 6, the catheter 10 further includes a handle 40 fixed at the proximal portion 14 of the catheter. The handle 40 supports an actuator 42 (e.g., a knob, lever, button, dial, switch, or other device), which is configured to selectively actuate the turbine 118 to selectively drive the tissue removal element 24 to rotate from a position outside the body cavity (e.g., away from the turbine). In one embodiment, the turbine 118 is disposed approximately 100 cm (about 39.4 inches) from the handle 40, but other distances are also within the scope of the present disclosure. The illustrated handle 40 includes a connection fitting 41, a pressure regulator 46, a needle valve 48, and a two-way valve 50. The connection fitting is configured to releasably connect the handle to a pressurized propellant source. The pressure regulator is configured to normalize the pressure of the propellant from the pressurized propellant source. The needle valve is configured to control the flow rate of the pressurized propellant. The two-way valves are all fluidly connected to each other in series. In the illustrated embodiment, the pressurized propellant source is a canister 44, which is releasably connected to the connection fitting 41 of the handle 40 and supported by the handle (broadly, the handle includes the pressurized canister). In this embodiment, the connection fitting 41 can be a quick-change fitting to allow the canister 44 to be quickly and easily attached to and detached from the handle 40. The canister 44 contains the propellant under pressure. In another embodiment, the pressurized propellant source can come from a source outside the handle 40 with a line (not shown) connected to the connection fitting 41. Preferably, the propellant is carbon dioxide (CO2), but any suitable pressurized propellant (e.g., a pressurized gas) can be used with the catheter 10 to power the turbine 118.

[0044] In the illustrated embodiment, actuator 42 is operatively connected to needle valve 48 to selectively control the flow of pressurized propellant. Actuator 42 is disposed on handle 40 for movement relative to the handle to selectively fluidly couple a source of pressurized propellant (e.g., canister 44) to turbine 118. Actuator 42 selectively operates needle valve 48 to selectively control the flow of propellant to turbine 118. Preferably, actuator 42 is movable relative to handle 40 to a non-actuated position and a plurality of actuated positions for variably adjusting the flow of pressurized propellant through needle valve 48 and thus adjusting the speed of turbine 118. In the non-actuated position, actuator 42 operates needle valve 48 such that the needle valve is closed and no propellant can pass therethrough. This prevents turbine 118 from rotating and thereby prevents the tissue removal element from rotating. In each of the actuated positions, actuator 42 controls the degree to which needle valve 48 is open to regulate the flow through the needle valve and thus the speed at which turbine 118 rotates the tissue removal element 24. It should be understood that in other embodiments, other suitable actuators (including but not limited to touchscreen actuators, wireless control actuators, controller-guided automated actuators, etc.) may be suitable for selectively actuating the motor. Additionally, preferably, the pressure setting of pressure regulator 46 is also adjustable, such as by a second actuator (not shown), such that the pressure of the propellant supplied to turbine 118 can be varied. By adjusting the pressure and flow of the pressurized propellant with pressure regulator 46 and needle valve 48, respectively, the torque and speed of turbine 118 can be adjusted to meet the desired rotational speed and torque of tissue removal element 24.

[0045] Reference Figure 1 、 3 and 3A, proximal body portion 12b extends distally from handle 40 to turbine 118 and fluidly connects the handle to the turbine. Proximal body portion 12b includes supply line 52, which defines a supply fluid passage 51 ( Figure 3A ), which provides fluid communication between handle 40, specifically two-way valve 50, to deliver a flow of pressurized propellant from a source of pressurized propellant (e.g., canister 44) to turbine 118. As Figure 2 and 3As shown, the distal portion of supply line 52 extends through a proximal opening defined by the tip 138 of the conical wall 136. The distal portion of supply line 52 extends distally through tip 138 and outlet chamber 142 to the partition wall 134. Specifically, the distal end of supply line 52 is attached to partition wall 134 at inlet opening 168 such that supply fluid passage 51 is fluidly connected to outer passage 162. In the illustrated embodiment, there are three circumferentially and evenly spaced inlet openings 168 in partition wall 134, and the distal portion of supply line 52 branches into three distal supply lines 52a, each distal supply line connected to one of the inlet openings. This provides a more uniform initial distribution of the propellant in rotor chamber 140. In other embodiments, there may be more or fewer than three inlet openings 168 and distal supply lines 52a.

[0046] The proximal body portion 12b also includes a return line 54 that extends along at least a portion of the proximal body portion and defines a return fluid passage 56 ( Figure 3A ), the return fluid passage providing fluid communication between the turbine 118 and the exhaust pipe 58 of the conduit 10 ( Figure 1 ) to convey pressurized propellant from the turbine to the exhaust pipe. As Figure 3 shown, the distal end of the return supply line 54 extends proximally from a proximal opening defined by the tip 138 of the conical wall 136. Specifically, the distal end of the return supply line is attached to the conical wall 136 at tip 138 such that return fluid passage 56 is fluidly connected to outlet chamber 142. In the illustrated embodiment, supply line 52 extends through return line 54 such that the supply line is disposed within return fluid passage 56 (e.g., the return line encloses the supply line). In this manner, proximal body portion 12b is a multi-chamber line for delivering pressurized propellant to and from turbine 118. In other embodiments, supply line 52 and return line 54 may be arranged side by side ( Figure 7 ).

[0047] Refer to Figure 1 、 5 and 6, the exhaust pipe 58 is configured to release the pressurized propellant into the surrounding atmosphere after the propellant has powered (e.g., flowed through) the turbine 118. The exhaust pipe 58 may be part of the handle 40, or the exhaust pipe may be a separate component spaced from the handle. As Figure 5 shown, in one embodiment, the exhaust pipe 58 is connected in series with the pressurized propellant source (e.g., tank 44) and the turbine 118 such that in operation the propellant flows from the pressurized propellant source through the turbine and out through the exhaust pipe. As Figure 1 and 6As shown, in one embodiment, the exhaust pipe 58 is connected in parallel with the turbine 118 such that the exhaust pipe applies a vacuum in the return fluid passage 54 to increase the pressure drop across the turbine, thereby increasing the rotational speed and / or torque of the rotor. In this embodiment, the proximal body portion 12b of the conduit 10 includes an exhaust supply line 53 fluidly connected to a pressurized propellant source and the exhaust pipe 58 such that a portion of the pressurized propellant supplied by the source (e.g., tank 44) is diverted away from the turbine 118 and flows directly into the exhaust pipe and then out of the exhaust pipe. This embodiment still includes a return line 54 to convey the propellant from the turbine 118 to the exhaust pipe 58. The exhaust pipe 58 discharges both the diverted propellant from the exhaust supply line 53 and the propellant from the return line 54. Since the exhaust pipe 58 discharges a portion of the propellant directly from the pressurized propellant source (e.g., tank 44) and is also connected to the return line 54, a vacuum is created in the return line 54 that draws propellant from the turbine 118. Specifically, the exhaust pipe 58 restricts the flow of pressurized propellant from the exhaust supply line 53 to create a Venturi Effect (see Figure 1 ) before the propellant from the return line 54 mixes with the propellant from the exhaust supply line. As a result, the pressure in the return line 54 is reduced (starting from normal atmospheric pressure), which increases the pressure drop across the turbine 118 - improving the efficiency of the turbine.

[0048] Referring Figures 14 - 21 , as described above, the distal body portion 12a of the conduit 10 includes an elongate liner 28, an elongate drive shaft 26, and a sheath 30. The sheath 30 includes a tubular sleeve configured to isolate and protect at least a portion of the subject's arterial tissue within the body cavity from the rotary drive shaft 26 and the liner 28. The inner diameter of the sheath 30 is sized to provide a clearance for the drive shaft 26. The space between the sheath 30 and the drive shaft 26 allows the drive shaft to rotate within the sheath and provides a region for saline perfusion between the sheath and the drive shaft. The outer diameter of the sheath 30 can be sized to provide a clearance with the inner diameter of a guiding catheter (not shown) to deliver the conduit 10 to a desired location within the body cavity. In one embodiment, the inner diameter of the sheath is approximately 0.050 inches (1.27 mm) and the outer diameter is approximately 0.055 inches (1.4 mm). Without departing from the scope of the present disclosure, the sheath can have other dimensions. In one embodiment, the outer sheath is made of polytetrafluoroethylene (PTFE). Alternatively, the sheath can include a multi-layer construction. For example, the outer sheath can include a perfluoroalkoxy (PFA) inner layer, an intermediate braided wire layer, and a Pebax outer layer.

[0049] The drive shaft 26 can include a tubular stainless steel coil configured to transfer rotation and torque from the turbine 118 to the tissue removal element 24. Configuring the drive shaft 26 as a coiled structure provides the drive shaft with flexibility that facilitates delivery of the catheter 10 through a body cavity. Moreover, when the catheter 10 traverses a curved path, the coiled configuration allows rotation and torque of the drive shaft 26 to be applied to the tissue removal element 24. The stiffness of the drive shaft 26 also affects the ease with which the coil traverses the body cavity and the ability of the coil to effectively transfer torque to the tissue removal element 24. In one embodiment, the drive shaft 26 is relatively stiff such that axial compression and extension of the coil are minimized during movement of the catheter 10 through the body cavity. In one embodiment, the drive shaft 26 has an inner diameter of about 0.023 inches (0.6 mm) and an outer diameter of about 0.035 inches (0.9 mm). The drive shaft 26 can have a single layer construction. For example, the drive shaft can include a 7-wire (e.g., strand) coil having a twist angle of about 30 degrees. Alternatively, without departing from the scope of the present disclosure, the drive shaft 26 can be of a multi-layer configuration. For example, the drive shaft 26 can include a base coil layer and a jacket (e.g., Tecothane TM ) disposed over the base layer. In one embodiment, the drive shaft includes a 15-wire coil having a twist angle of about 45 degrees. Tecothane TM The jacket can be disposed over the coil. Alternatively, the drive shaft 26 can include a dual coil layer configuration that also includes an additional jacket layer over the two coil layers. For example, the drive shaft can include an inner coil layer and an outer coil layer, the inner coil layer including a 15-wire coil having a twist angle of about 45 degrees and the outer coil layer including a 19-wire coil having a twist angle of about 10 degrees. Other configurations of the drive shaft 26 are also contemplated.

[0050] The inner liner 28 includes a multi-layer tubular body configured to isolate the guide wire 22 from the drive shaft 26, the tissue removal element 24, and in some embodiments the drive shaft 150. The inner liner 28 is fixedly attached to the turbine 118 to prevent relative movement between the inner liner and the turbine. Thus, the inner liner 28 remains stationary and prevents translation of the inner liner relative to the turbine 118. Additionally, rotation of the inner liner 28 due to rotation of the drive shaft 26 is prevented. The inner liner 28 has an inner diameter ID sized to pass over the guide wire 22( Figure 17) By isolating the guide wire 22 from the rotatable drive shaft 150 and the drive shaft 26, the inner liner 28 protects the guide wire from rotational damage by the drive shaft and the drive shaft. The inner liner 28 also extends past the tissue removal element 24 to protect the guide wire 22 from the rotating tissue removal element. Thus, the inner liner 28 is configured to prevent any contact between the guide wire 22 and the components of the catheter 10 that rotate around the guide wire. Thus, any metal-to-metal engagement is eliminated by the inner liner 28. This isolation of the drive shaft 150, the drive shaft 26, and the tissue removal element 24 from the guide wire 22 also ensures that the rotation of the drive shaft 26 and the tissue removal element 24 is not transmitted or transferred to the guide wire 22. Thus, a standard guide wire 22 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. Additionally, by extending through the tissue removal element 24 and past the distal end of the tissue removal element, the inner liner 28 stabilizes the tissue removal element by providing a central axis for the tissue removal element to rotate around the inner liner.

[0051] Reference Figure 18 , in one embodiment, the inner liner 28 includes an inner PTFE layer 60, an intermediate braided layer 62 made of stainless steel, and a polyimide drive shaft 64. The PTFE inner layer 60 provides a lubricated interior for the inner liner 28, which aids the passage of the guide wire 22 through the inner liner. The braided stainless steel intermediate layer 62 provides rigidity and strength to the inner liner 28 such that the inner liner can withstand the torsional forces applied to the inner liner by the drive shaft 26. In one embodiment, the intermediate layer 62 is formed of 304 stainless steel. The outer polyimide layer 64 provides abrasion resistance as well as having a lubricating quality, which reduces the friction between the inner liner 28 and the drive shaft 26. Additionally, a lubricating film, such as silicone, can be added to the inner liner 28 to reduce the friction between the inner liner and the drive shaft 26. In one embodiment, the inner diameter ID of the inner liner 28 is approximately 0.016 inches (0.4 mm), the outer diameter OD is approximately 0.019 inches (0.5 mm), and the length is approximately 39.4 inches (approximately 100 cm). The inner diameter of the inner liner 28 provides clearance for a standard 0.014-inch guide wire 22. The outer diameter of the inner liner 28 provides clearance for the drive shaft 150, the drive shaft 26, and the tissue removal element 24. Having a space between the inner liner 28 and the drive shaft 26 reduces the friction between the two components and allows for saline perfusion between the components.

[0052] In one embodiment, a marker band 66 ( Figure 15 ) is disposed on the outer surface of the distal end of the inner liner 28. The marker band 66 configures the tip of the inner liner 28 to be fluoroscopically visible, which allows the physician to verify the positioning of the inner liner during a medical procedure. In this embodiment, the distal end of the inner liner 28 can be laser cut to provide a low-profile tip. In one embodiment, the marker band 66 includes a platinum-iridium strip.

[0053] It is further contemplated that, without departing from the scope of the present disclosure, the distal end of the inner liner 28 can have other configurations. For example, an atraumatic tip 68 ( Figure 19 ) can be attached to the distal end of the inner liner 28. The atraumatic tip 68 provides a soft low-profile distal end to facilitate delivery of the inner liner 28 through a body cavity without causing damage. The maximum outer diameter of the atraumatic tip 68 can be about 0.02 inches (0.6 mm). Other sizes of the atraumatic tip 68 are also contemplated. In another embodiment, a tapered tip 70 ( Figure 20 ) can be attached to the distal end of the inner liner 28. The tapered tip 70 can be formed of a layer of material configured to protect the distal end of the inner liner 28.

[0054] Referring Figure 15 , the tissue removal element 24 extends longitudinally along the longitudinal axis LA of the catheter 10 from a proximal end adjacent to the distal portion of the drive shaft 26 to the opposite distal end. The tissue removal element 24 is operatively connected to the turbine 118 through the drive shaft 26 for rotation by the turbine. When the catheter 10 is inserted into a body cavity and the turbine 118 is actuated to rotate the drive shaft 26, thereby rotating the tissue removal element 24. Any suitable tissue removal element 24 can be used for removing tissue in the body cavity when the tissue in the body cavity is rotated. In one embodiment, the tissue removal element 24 includes abrasive burrs configured to abrade tissue in the body cavity when the turbine 118 rotates the abrasive burrs. The abrasive burrs 24 can have an abrasive outer surface formed, for example, by a diamond grit coating, surface etching, etc. In one embodiment, the tissue removal element 24 includes stainless steel spheroids, the outer surface of which contains 5 μm of exposed diamond crystals. The tissue removal element 24 can also be radiopaque to allow the tissue removal element to be visible under fluoroscopy. In other embodiments, the tissue removal element can include one or more cutting elements having smooth or serrated cutting edges (e.g., annular cutting edges), impregnators, thrombectomy wires, etc.

[0055] Referring Figure 21 , in one embodiment, a cavity 72 extends longitudinally through the tissue removal element 24 such that the tissue removal element defines openings at its proximal and distal ends. The cavity 72 receives a portion of the drive shaft 26 for mounting the tissue removal element 24 to the drive shaft ( Figure 16)。The cavity 72 includes a first diameter portion 74 extending from the proximal end of the tissue removal element 24, a tapered diameter portion 76 extending from the first diameter portion toward the distal end of the tissue removal element, and a second diameter portion 78 extending from the tapered diameter portion to the distal end of the tissue removal element. The diameters of the first diameter portion 74 and the second diameter portion 78 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. In one embodiment, the diameter D1 of the first diameter portion 74 is approximately 0.035 inches (0.9 mm), and the diameter D2 of the second diameter portion 78 is approximately 0.022 inches (0.56 mm). The tapered diameter portion 76 provides a transition between the first diameter portion 74 and the second diameter portion 78. The drive shaft 26 is received within the first diameter portion 74, and the distal end of the drive shaft abuts the tapered diameter portion 76( Figure 16 )。The tissue removal element 24 can be fixedly attached to the distal end of the drive shaft 26 in any suitable manner. In one embodiment, an adhesive bonds the tissue removal element 24 to the drive shaft 26. The liner 28 extends through the second diameter portion 78 of the drive shaft 26 and the tissue removal element 24. The second diameter portion 78 is sized to pass over the liner 28 with a small clearance. The inner diameter D2 provides a clearance between the tissue removal element 24 and the liner 28 to reduce friction between the components and allow space for saline perfusion. Thus, the tissue removal element 24 is shaped and arranged to extend around at least a portion of the drive shaft 26 and the liner 28, and thus provides a relatively compact assembly for abrading tissue at the distal portion of the catheter 10.

[0056] The outer surface of the tissue removal element 24 includes a proximal section 80, an intermediate section 82, and a distal section 84. The diameter of the proximal section 80 increases from the proximal end of the tissue removal element 24 to the intermediate section 82. The intermediate section has a constant diameter and extends from the proximal section 80 to the distal section 84. The diameter of the distal section 84 tapers from the intermediate section 82 to the distal end of the tissue removal element 24. The tapered distal section 84 provides a generally wedge-shaped configuration for the tissue removal element 24 to wedge open a constricted tissue passage while removing tissue by the abrading action of the tissue removal element to open the passage at the same time. The distal end of the tissue removal element 24 is also rounded to provide a blunt distal end for the tissue removal element.

[0057] Reference Figure 1 and 14, to remove tissue from a subject's body cavity, a practitioner inserts a guide wire 22 into the subject's body cavity to a distal position of the tissue to be removed. Subsequently, the practitioner inserts the proximal portion of the guide wire 22 through the distal end of the guide wire lumen 20 of the inner liner 28 and through the turbine 118 such that the guide wire extends through the guide wire port 120 in the turbine to exit the catheter 10. With the catheter 10 loaded onto the guide wire 22, the practitioner advances the catheter along the guide wire until the tissue removal element 24 is positioned proximal to and adjacent the tissue. When the tissue removal element 24 is positioned proximal to and adjacent the tissue, the practitioner actuates the turbine 118 using the actuator 42 to open the needle valve 48, thereby allowing pressurized propellant from a pressurized propellant source (e.g., canister 44) that was previously fluidly connected to the handle 40 to flow through the turbine 118 and rotate the rotor 124, drive shaft 26, and the tissue removal element mounted on the drive shaft. The tissue removal element 24 abrades (or otherwise removes) the tissue in the body cavity as it rotates. As the tissue removal element 24 rotates, the practitioner can selectively move the catheter 10 distally along the guide wire 22 to abrade the tissue and, for example, increase the size of the passage through the body cavity. The practitioner can also move the catheter 10 proximally along the guide wire 22 and can repeatedly move the assembly in the distal and proximal directions to obtain a back-and-forth movement of the tissue removal element 24 across the tissue. When the practitioner is finished using the catheter 10, the catheter can be removed from the body cavity. In one embodiment, a 12-gram CO2 canister 44 is the pressurized propellant source fluidly connected to the catheter 10, and the pressurized propellant source can continuously power the turbine 118 at approximately 80,000 RPM with a torque of approximately 1.5 mNm for approximately 8.5 to 20 minutes. CO2 is one of the preferred propellants because during use, if any CO2 leaks or escapes from the catheter 10 (e.g., turbine 118, proximal body portion 12b, etc.) and enters the body cavity, it can be easily absorbed by the subject's blood.

[0058] When the practitioner operates actuator 42 to open and set the position of needle valve 48, pressurized propellant flows from the pressurized propellant source through supply line 52 and into rotor chamber 140 of turbine 118. Specifically, the propellant flows through outer passageway 162, transition section 164, inner passageway and into outlet chamber 162. The propellant flowing distally through outer passageway 162 is redirected (e.g., a 180° change in direction) as the propellant flows through transition section 164 and then flows proximally through inner passageway 166. As the propellant moves through inner passageway 166, the propellant contacts impeller 154 that rotates rotor 124. Rotor 124 may be configured to rotate clockwise or counterclockwise. After the propellant causes rotor 124 to rotate within inner passageway 160, the propellant moves through outlet chamber 162 and into return line 54 toward exhaust pipe 58, in which the propellant is discharged to the surrounding atmosphere. If exhaust pipe 58 is configured to apply a vacuum on return line 54, a portion of the propellant will flow directly to the exhaust pipe through exhaust supply line 53 to create a vacuum when actuator 42 is operated to initiate the flow of propellant in supply line 52, as described above.

[0059] Guidewire port 120 permits the catheter 10 to be used in rapid exchange and single operator exchange procedures. Since turbine 118 is spaced distally from handle 40 and defines guidewire port 120 (e.g., the proximal end of the guidewire lumen), the guidewire lumen is much shorter than the total length of catheter 10. This enables catheter 10 to be removed from the body cavity in a rapid exchange or single operator exchange procedure without pulling guidewire 22 out of the body cavity with the catheter because the length of the guidewire is longer than the length of the guidewire lumen 20 of the catheter. Thus, at least a portion of guidewire 22 is always exposed and can be grasped by the practitioner. Additionally, since turbine 118 is spaced distally from handle 40, the total length of the rotary drive shaft (e.g., drive shaft 26) extending along elongate body 12 is reduced.

[0060] Reference Figures 7 - 13, another embodiment of a turbine for use with the catheter 10 is generally designated by 218. It should be understood that the turbine 218 may be interchangeable with the turbine 118 such that either turbine may be used with the embodiments of the catheter 10 described herein. Thus, the references made above to the turbine 118 as part of the catheter 10 apply equally to the turbine 218. The turbine 218 of the second embodiment includes a housing (e.g., stator) 222 that surrounds a rotor 224, the rotor being configured to rotate within the housing, and the rotor being operatively connected to the tissue removal element 24 such that rotation of the rotor within the housing drives rotation of the tissue removal element. In one embodiment, the turbine 218 is configured to rotate the tissue removal element 24 at a speed greater than about 80,000 RPM while generating a torque of about 1.5 mNm. In one embodiment, the turbine 218 is a micro turbine sized and arranged to be received within a body cavity of a subject. In one embodiment, the outer diameter of the turbine 218 is from about 0.5 mm to about 4 mm. The turbine 218 is sized such that it can be received within a guide catheter (not shown). In one embodiment, the turbine 218 is sized such that the catheter 10 can be received within a guide catheter having a diameter of 7F (about 2 mm) or less. In another embodiment, the turbine 218 is sized such that the catheter 10 can be received within a guide catheter having a diameter of 6F (about 1.8 mm) or less. The turbine 218 is intubated such that the turbine is a through-hole turbine. In this manner, the turbine 218 defines a portion of the guidewire lumen 20 that extends along the drive axis DA of the turbine ( Figure 13 ). The portion of the guidewire lumen 20 defined by the turbine 218 is aligned with the portion of the guidewire lumen defined by the liner 28 of the distal body portion 12a (e.g., the drive axis DA is coaxial with the longitudinal axis LA of the catheter 10) such that the guidewire 22 can extend from the distal body portion into the turbine or vice versa without bending, kinking, or changing direction.

[0061] The housing 222 includes a distal housing 230 and a proximal cap 232. The distal housing 230 has a distal portion 234 and an outer cylindrical wall 236 that extends proximally from the distal portion. The outer wall 236 defines a rotor chamber 240 in which the rotor 224 is disposed and rotates. The proximal cap 232 is fixed to the proximal end of the outer wall 236. In the illustrated embodiment, the proximal cap 232 is sized and shaped to be inserted into the outer wall 236 from its distal end. The cap 232 defines an inlet passage 242 and an outlet passage 244 that are in fluid communication with the rotor chamber 240. As Figure 11As shown, the inlet passage 242 and the outlet passage 244 are located on the same side of the cap 232 but are spaced apart. In other words, the inlet passage 242 and the outlet passage 244 are arranged to be separated by approximately 1.6 radians (90°). The inlet passage 242 is fluidly connected to the supply fluid passage 51 of the supply line 52 and delivers the propellant into the rotor chamber 240. The outlet passage 244 is fluidly connected to the return fluid passage 56 of the return line 54 and transports the propellant from the rotor chamber 240. In one embodiment, the distal portions of the supply line 52 and the return line 54 are respectively disposed in at least a portion of the inlet passage 242 and the outlet passage 244 and are fixed to the cap 232. As Figure 11 shown, the distal portion of the inlet passage 242 is configured to direct the propellant in a direction that at least partially wraps around the drive axis DA. Similarly, the distal portion of the outlet passage 244 is configured to receive the propellant in a direction that at least partially wraps around the drive axis DA. In this way, the inlet passage 242 and the outlet passage 244 contribute to facilitating the rotation of the rotor 124 as the propellant flows through the rotor chamber 240 (such as Figure 11 shown rotating clockwise), as described in more detail below.

[0062] The rotor 224 is disposed in the rotor chamber 240 and is configured to rotate therein. The rotor 224 includes a cylindrical output shaft 250 that extends distally from the proximal cap 232 through the rotor chamber 140 to the distal portion 234 of the housing 230. The output shaft 250 is aligned with the drive axis DA and defines a portion of the guidewire lumen 20 (e.g., the output shaft has a hole therethrough). The proximal portion of the output shaft 250 is rotatably disposed in the proximal cap 232 (e.g., supported by the proximal cap). The proximal cap 232 defines a cylindrical cavity 252 that is aligned with the drive axis DA and extends proximally from the distal end of the cap. The proximal portion of the output shaft 250 is disposed in the cavity 252 such that the output shaft can rotate therein. The distal portion of the output shaft 250 is rotatably disposed in the distal portion 234 of the housing 230 (e.g., supported by the distal portion). The distal portion 234 of the housing 230 defines an opening (aligned with the drive axis DA) through which the distal portion of the output shaft 250 extends distally. A pair of jewel bearings 254 and 256 are respectively fixed to the distal portion 234 of the housing 230 and the cap 232. Specifically, one jewel bearing 254 is disposed in the opening defined by the distal portion 234 of the housing 230 and the other jewel bearing 256 is disposed in the cavity 252 (e.g., the housing and the cap hold the bearings in place). The jewel bearings 254, 256 respectively receive the proximal portion and the distal portion of the output shaft 250 and facilitate the rotation of the output shaft in the housing 222. The jewel bearings 254, 256 can be made of bronze. However, other materials are also conceivable. For example, the bearings can also be made of zirconia.

[0063] The rotor 24 includes a plurality of circumferentially spaced blades 260 fixed to an intermediate portion of the output shaft 250. Each blade 260 extends longitudinally along the output shaft 250 and extends radially outward therefrom (e.g., away from the drive axis DA) into the rotor chamber 240. The inner diameter of the outer wall 236 is greater than the outer diameter of the blade 260 to provide the necessary clearance to allow the blade to rotate within the rotor chamber 240. In the illustrated embodiment, the rotor 224 includes eight blades 260, but the rotor 224 may have more or fewer blades. As Figures 9 - 11 shown, each blade 260 is curved and defines a seat 262 having a generally semi-cylindrical shape with hemispherical ends. Thus, as Figure 11 shown, each blade 260 has a generally semi-circular (e.g., semi-circular) cross-sectional shape. The blades 260 are oriented such that the seat 262 will receive the propellant as the propellant flows into the rotor chamber 240 through the inlet passage 242. In the illustrated embodiment, this results in the seat 262 being located on the counterclockwise side of the blade 260, where the clockwise side is generally curved to reduce friction as the blade rotates in the clockwise direction. Other shaped blades 260 are also within the scope of the present disclosure. In one embodiment, the rotor 224 is integrally formed as a one-piece assembly.

[0064] The rotor 224 is operatively connected (e.g., attached) to the drive shaft 26 of the distal body portion 12a to drive the rotation of the tissue removal element 24. In one embodiment, the proximal portion of the drive shaft 26 extends along the drive shaft 250 and is fixed to the drive shaft by any suitable means, such as but not limited to an adhesive ( Figure 13 ). In other embodiments, the drive shaft 26 may be mechanically fastened to the output shaft 250. In one embodiment, the distal portion of the output shaft 250 includes a seat (not shown) for receiving the distal portion of the drive shaft 26. The distal portion of the drive shaft 26 is fixed within the seat to attach the drive shaft to the output shaft 250.

[0065] In the illustrated embodiment, the housing 222 of the turbine 218 further includes a flexible proximal portion 296 and a flexible distal portion 298 that are respectively fixed to and extend proximally and distally from the distal ends of the proximal portion and the distal portion 234 of the cap 232 to provide strain relief for the turbine 218 by reducing the tension applied to the turbine when the catheter 10 is bent (e.g., manipulated) during use. Additionally, the flexible proximal portion 296 defines a guidewire port 220 and a portion of the guidewire lumen 20. The guidewire port 220 enables the turbine 218 to have the quick-change feature discussed above. The cap 232 also defines a portion of the guidewire lumen 20, specifically the portion that extends between the output shaft 250 and the flexible proximal portion 296. The proximal body portion 12b is connected to the flexible proximal portion 296, and the distal body portion 12a is connected to the flexible distal portion 298. Specifically, the supply line 52 and the return line 54 extend distally through the flexible proximal portion 296 to the proximal cap 232. Similarly, the sheath 30, the drive shaft 26, and the liner 28 extend proximally through the flexible distal portion 298 to the outer housing 230. In other words, both the flexible proximal portion 296 and the flexible distal portion 298 define cavities sized and shaped to receive the proximal portion of the distal body portion 12a and the distal portion of the proximal body portion 12b. As Figure 13 shown, the sheath 30 extends proximally into and is fixed within the flexible distal portion 298 ( Figure 13 ), the drive shaft 26 extends proximally through the flexible distal portion to the output shaft 250, and the liner 28 extends proximally through the flexible distal portion, the output shaft, the cap 232, and into the flexible proximal portion 296 and is fixed to the flexible proximal portion. Preferably, the flexible proximal portion 296 and the flexible distal portion 298 taper inwardly as they extend proximally and distally from the outer housing 230 and the cap 232, respectively. The outer housing 230, the cap 232, and the flexible proximal portion 296 and the flexible distal portion 298 preferably have the same maximum outer diameter such that the turbine 218 has a smooth outer surface. The distal outer housing 230, the proximal cap 232, and the rotor 224 may be formed of polyetheretherketone (PEEK).

[0066] In operation, turbine 218 operates in conduit 10 in the same manner as turbine 118, with the main difference being how the pressurized propellant flows through turbine 218. When the practitioner operates actuator 42 to open and set the position of needle valve 48, the pressurized propellant flows from the pressurized propellant source through supply line 52 and into rotor chamber 240 of turbine 218. Specifically, inlet passage 242 directs the pressurized propellant into rotor chamber 240 in an angled direction (e.g., not parallel to drive axis DA) such that the pressurized propellant will contact blades 260 (specifically, enter seat ring 262) and cause rotor 224 to rotate in a clockwise direction ( Figure 10 ). It should be understood that turbine 218 may be configured such that rotor 224 rotates in a counterclockwise direction. As the propellant moves through rotor chamber 240, the propellant contacts blades 260 that cause rotor 224 to rotate. As rotor 224 rotates, additional blades 260 will pass by inlet passage 242 and contact the pressurized propellant, thereby further rotating the rotor (e.g., continuously). The propellant flows clockwise around output shaft 250 approximately 4.7 radians (270°) until the propellant reaches outlet passage 244 ( Figure 10 and 12 ). The propellant then moves through outlet passage 244 and into return line 54 toward exhaust pipe 58, in which the propellant is discharged into the surrounding atmosphere. It should be understood that turbine 218 may be used with exhaust pipe 58 that applies a vacuum to the turbine.

[0067] Modifications and variations may be made to the disclosed embodiments without departing from the scope of the invention defined in the appended claims. For example, given a particular size, it should be understood that it is merely exemplary and other sizes are possible.

[0068] When introducing elements of the invention or one or more of its embodiments, the articles "a", "an", "the", and "said" are intended to mean that there is 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.

[0069] Since various changes may be made to the above devices, systems, and methods without departing from the scope of the invention, it is intended that all subject matter contained in the above description and shown in the accompanying drawings be interpreted in an illustrative rather than a limiting sense.

Claims

1. A tissue removal catheter for removing tissue in a body cavity, the tissue removal catheter comprising: An elongate body having an axis and a proximal portion and a distal portion spaced apart from each other along the axis, the size and shape of the elongate body being configured to be received in the body cavity; A turbine fixed to the elongate body and positioned at an intermediate location between the proximal portion and the distal portion of the elongate body; A rotatable tissue removal element located at the distal portion of the elongate body and operatively coupled to the turbine such that the turbine rotates the tissue removal element, the turbine being entirely proximal to the rotatable tissue removal element, and a flexible portion of the elongate body being located between the turbine and the rotatable tissue removal element, the tissue removal element being configured to remove the tissue from the body cavity when the tissue removal element is rotated by the turbine; And A guidewire lumen extending from the distal end of the elongate body through the elongate body to the turbine, the guidewire lumen being configured to receive a guidewire such that the elongate body can be moved proximally and distally along the guidewire.

2. The tissue removal catheter according to claim 1, wherein the turbine defines a guidewire port for receiving the guidewire, the guidewire port defining the proximal end of the guidewire lumen.

3. The tissue removal catheter according to claim 1, wherein the turbine includes a rotor and a stator, the rotor being configured to rotate about a drive axis of the turbine, the drive axis being coaxial with the axis of the elongate body.

4. The tissue removal catheter according to claim 3, wherein the rotor defines a portion of the guidewire lumen.

5. The tissue removal catheter according to claim 3, wherein the rotor is disposed in a rotor chamber defined by the stator and is configured to rotate therein.

6. The tissue removal catheter according to claim 5, wherein the rotor includes at least one impeller.

7. The tissue removal catheter according to claim 5, wherein the rotor includes at least one blade extending longitudinally along the rotor.

8. The tissue removal catheter according to claim 5, further comprising a handle mounted to the proximal portion of the elongate body and operable to deliver a propellant flow to the turbine to rotate the rotor.

9. The tissue removal catheter according to claim 8, wherein when the propellant flow is delivered to the turbine, the propellant flows proximally and distally within the rotor chamber.

10. The tissue removal catheter according to claim 8, wherein when the propellant flow is delivered to the turbine, the propellant flows circumferentially around the rotor within the rotor chamber.

11. The tissue removal catheter according to claim 8, wherein the elongated body further comprises a supply line that extends between the handle and the turbine and is configured to deliver the propellant flow from the handle to the turbine.

12. The tissue removal catheter according to claim 11, further comprising an exhaust pipe that is fluidly connected to the turbine and is configured to discharge the propellant into the atmosphere around the exhaust pipe after at least a portion of the propellant has flowed through the turbine.

13. The tissue removal catheter according to claim 12, wherein the elongated body further comprises a return line that extends between the turbine and the exhaust pipe and is configured to convey the propellant to the exhaust pipe after the propellant has flowed through the turbine.

14. The tissue removal catheter according to claim 13, wherein the exhaust pipe applies a vacuum on the turbine to facilitate the movement of the propellant through the turbine.

15. The tissue removal catheter according to claim 14, further comprising an exhaust supply line that extends between the handle and the nozzle and is configured to divert a portion of the propellant from the turbine and directly into the exhaust pipe.

16. The tissue removal catheter according to claim 15, wherein the exhaust pipe restricts the propellant flow from the exhaust supply line before the propellant flows from the return line and the exhaust supply line are mixed to apply a vacuum on the turbine.

17. The tissue removal catheter according to claim 8, wherein the handle further comprises a tank configured to hold the propellant under pressure.

18. The tissue removal catheter according to claim 8, wherein the handle further comprises a selectively operable needle valve for controlling the flow rate of the propellant to the turbine and a selectively operable pressure regulator for controlling the pressure of the propellant.

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