Tissue removal catheter including a tissue removal element having a beveled distal end face

Abstract

A tissue removal catheter for removing tissue in a body lumen includes an elongated catheter body. A tissue removal element is operatively coupled to a distal end portion of the elongated catheter body. The tissue removal element has a central axis. The tissue removal element is configured to rotate about its central axis to remove tissue from the body lumen. A distal end portion of the tissue removal element includes a distal face at a distal-most end of the tissue removal element. The distal face has a perimeter and a diameter extending through the central axis. Diametrically opposed points on the perimeter lie in a plane that is tilted with respect to the central axis of the tissue removal element.

Description

Technical Field

[0001] This disclosure generally relates to a tissue removal catheter, and more particularly to a tissue removal catheter including a rotatable tissue removal element having an inclined distal face. Background Technology

[0002] Tissue removal catheters are used to remove unwanted tissue from body cavities. As an example, atherosclerotic resection catheters are used to remove material from blood vessels to clear them and improve blood flow. This method can be used in patients with severe calcified coronary artery lesions to prepare the lesions within the patient's coronary arteries for percutaneous transluminal coronary angioplasty (PTCA) or stent delivery. Atherosclerotic resection catheters may employ rotating elements that abrade or otherwise reduce the volume of unwanted tissue. Summary of the Invention

[0003] In one aspect, a tissue removal catheter for removing tissue from a body cavity includes an elongated catheter body having a longitudinal axis and proximal and distal portions spaced apart from each other along the longitudinal axis. The elongated catheter body is sized and shaped to be received within a body cavity. A tissue removal element is operatively coupled to the distal portion of the elongated catheter body. The tissue removal element has a central axis and proximal and distal portions spaced apart from each other along the central axis of the tissue removal element. The tissue removal element is configured to rotate about its central axis to remove tissue from the body cavity. The distal portion of the tissue removal element includes a distal facet at the distal end of the tissue removal element. The distal facet has a periphery and a diameter extending through the central axis. Points on the periphery opposite the diameter lie in a plane inclined relative to the central axis of the tissue removal element.

[0004] On the other hand, a tissue removal catheter for removing tissue from a body cavity includes an elongated catheter body having a longitudinal axis and proximal and distal portions spaced apart from each other along the longitudinal axis. The elongated catheter body is sized and shaped to be received within a body cavity. A tissue removal element is operatively coupled to the distal portion of the elongated catheter body. The tissue removal element has a central axis and proximal and distal portions spaced apart from each other along the central axis of the tissue removal element. The tissue removal element is configured to rotate to remove tissue from the body cavity. The distal portion of the tissue removal element includes a distal face at the most distal end of the tissue removal element. The distal face has a periphery extending around an opening and a diameter extending through an axis passing through the distal opening. Points on the periphery opposite the diameter lie in a plane inclined relative to the central axis of the tissue removal element. A distal opening extends through the distal face. The distal opening in the distal face has an axis.

[0005] A method for reducing the volume of a lesion in a blood vessel using a rotary atherosclerotic catheter includes advancing a tissue removal element of the rotary atherosclerotic catheter toward the lesion in the blood vessel. The tissue removal element has a central axis and proximal and distal portions spaced apart from each other along the central axis. The distal portion of the tissue removal element includes a distal facet at its distal end. The distal facet has a periphery and a diameter extending through the central axis. Points on the periphery opposite the diameter lie in a plane inclined relative to the central axis of the tissue removal element. The tissue removal element is rotated about its central axis while the rotary atherosclerotic catheter is advanced through the blood vessel, whereby the rotation of the inclined distal facet of the tissue removal element is configured to facilitate release of the tissue removal element if the distal facet engages with an obstruction in the blood vessel as the rotary atherosclerotic catheter is advanced in the blood vessel.

[0006] Details of one or more aspects of this disclosure are set forth in the accompanying drawings and the following description. Other features, objects, and advantages of the technology described in this disclosure will become clear from the specification, drawings, and claims. Attached Figure Description

[0007] Figure 1 This is an elevation view of the tissue removal catheter of the present invention;

[0008] Figure 2 This is an enlarged elevation view of the distal portion of the catheter;

[0009] Figure 3 yes Figure 2 An enlarged local longitudinal section of the distal portion of the catheter;

[0010] Figure 4 This is a schematic representation of the tissue removal element of a tissue removal catheter engaging with an obstacle within a body cavity;

[0011] Figure 5 Similar to Figure 4 This illustrates a tissue removal element that rotates around an obstacle; and

[0012] Figure 6 Similar to Figure 4 This illustrates a tissue removal element that bypasses obstacles.

[0013] Figure 7 This is another embodiment of tissue removal.

[0014] Figure 8 This is yet another embodiment of tissue removal. Detailed Implementation

[0015] refer to Figure 1The rotary tissue removal catheter for removing tissue from body cavities is generally indicated by reference numeral 10. The illustrated catheter 10 is a rotary atherosclerotic resection device suitable for reducing (e.g., abrasion, cutting, resection, ablation, etc.) the volume of occluded tissue (e.g., embolic tissue, plaque tissue, sebaceous cyst, thrombolytic tissue, stenotic tissue, hyperplastic tissue, tumor tissue, etc.) from the vessel wall (e.g., coronary artery wall, etc.). Catheter 10 can be used to facilitate subsequent delivery of percutaneous coronary angioplasty (PTCA) or stents. Features of the disclosed embodiments can also be adapted to treat chronic total occlusion (CTO) of blood vessels and stenosis of other body cavities (e.g., ureters, bile ducts, airways, pancreatic ducts, lymphatic vessels, etc.). Hyperplastic cell growth often occurs due to tumors surrounding and invading body cavities. Therefore, removing such material can be beneficial in maintaining the patency of body cavities.

[0016] The catheter 10 shown is sized to be received in a blood vessel of the subject. While the remaining discussion relates to catheters for removing tissue from blood vessels, it should be understood that the teachings of this 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 occlusive stenosis or proliferative material in various body cavities.

[0017] refer to Figure 1 and Figure 2 The catheter 10 includes a catheter body generally indicated by 11. The catheter body 11 includes an elongated drive shaft 12 and an elongated liner 14 received in and extending along the drive shaft. The drive shaft 12 and the liner 14 extend from a proximal portion of the catheter body to a distal portion along a longitudinal axis LA of the catheter body. A tissue removal element 20 is operatively coupled to the distal end of the drive shaft 12 and configured to rotate to remove tissue from a body cavity, as will be explained in more detail below. The drive shaft 12 may include a coiled elongated body, which may be formed of stainless steel or other materials. A sheath 22 is disposed around the drive shaft 12. Both the drive shaft 12 and the liner 14 are configured to translate (i.e., move longitudinally) relative to the sheath 22. The size and shape of the catheter body 11 and the sheath 22 are configured for insertion into a body cavity of a subject. The sheath 22 isolates the body cavity from at least a portion of the catheter body 11, and more particularly from at least a portion of the drive shaft 12.

[0018] Liner 14 defines the guidewire lumen 24 ( Figure 3The guidewire lumen 24 is used to slidably receive the guidewire 26 therein, allowing the catheter body 11 to be advanced through the body cavity by traveling along the guidewire. The guidewire 26 may be a standard guidewire with an outer diameter of 0.014 inches (0.356 mm) and a length of 300 cm. In some embodiments, the liner 14 may have a lubricated inner surface for sliding on the guidewire 26 (e.g., the lubricated surface may be provided by a lubricating polymer layer or a lubricating coating). The guidewire lumen 24 extends from the proximal portion to the distal portion of the catheter body 11, allowing the guidewire 26 to extend along the entire working length of the catheter body. In one embodiment, the total working length of the catheter 10 may be between approximately 135 cm (53 inches) and approximately 142 cm (56 inches). The liner 14 protects the guidewire 26 from damage due to rotation of the drive shaft 12 by isolating the guidewire from the rotating drive shaft 12. The liner 14 shown also extends distally through the tissue removal element 20, such that the distal end of the liner is exposed outside the tissue removal element to protect the guidewire 26 from the effects of the rotating tissue removal element.

[0019] refer to Figure 1 The catheter 10 further includes a handle 40 fixed to the proximal portion of the catheter body. The handle 40 supports an actuator 42 (e.g., a lever, button, dial, switch, or other device) configured to selectively actuate a driver (e.g., a motor 43) disposed in the handle to drive the drive shaft 12 and the tissue removal element 20 to rotate. In the illustrated embodiment, the motor 43 is coupled to the drive shaft 12 via a gear assembly 44 supported by the handle 40 and an output shaft 48. A slider or pusher 45 is positioned on the handle 40 and operatively coupled to the driver 43 such that the driver 43, drive shaft 12, and tissue removal element 20 can be selectively advanced and retracted longitudinally relative to the handle 40 and the sheath 22. The handle 40 defines a groove that restricts movement of the slider 45 relative to the handle. Therefore, the length of the groove determines the amount of relative movement between the drive shaft 12 and the handle 40. An infusion port 46 may be disposed at the proximal end of the catheter 10. Port 46 communicates with the space between sheath 22 and drive shaft 12 for delivering fluid (e.g., saline) to cool the rotating drive shaft 12 during use. Proximal port 47 allows guidewire 26 and liner 14 to pass through the proximal end of handle 40. A guidewire lock (not shown) may be provided on handle 40 to lock guidewire 26 in place relative to handle, which may be desirable during rotation of tissue removal element 20 to remove unwanted tissue from body cavities.

[0020] In the illustrated embodiments, such as Figure 2 and Figure 3As shown, drive shaft adapter 88 connects tissue removal element 20 to drive shaft 12 to transmit rotation from drive shaft to tissue removal element. Drive shaft adapter 88 is fixedly (e.g., welded) to the proximal portion of tissue removal element 20 and fixedly (e.g., welded) to the distal portion of drive shaft 12. It should be understood that drive shaft 12 can be directly coupled to tissue removal element 20.

[0021] refer to Figure 3 The catheter 10 includes a coupling assembly, generally indicated by 57, that couples the tissue removal element 20 to the liner 14. The shown coupling assembly 57 includes a bushing 90 and bearing rings (e.g., a first bearing ring 98 and a second bearing ring 99) received around the bushing 90. The inner surface of the bushing 90 is fixedly attached to the liner 14. In one embodiment, an adhesive, such as epoxy resin, bonds the bushing 90 to the liner 14. Thus, the bushing 90 does not rotate about the liner 14. The first bearing ring 98 and the second bearing ring 99 are coupled to the tissue removal element 20 and / or the drive shaft adapter 88. When the tissue removal element 20 rotates, the bearing rings 98, 99 move against the bushing 90. The first bearing ring 98 and the second bearing ring 99 are configured to engage the shoulder 94 of the bushing 90 such that translational movement of the drive shaft 12 is transmitted to the bushing 90 and the liner 14. The coupling assembly 57 isolates the tissue removal element 20 from the liner 14 and is configured to allow the tissue removal element to rotate about the liner. It should be understood that the coupling assembly 57 can be omitted, allowing the tissue removal element to rotate directly on the guidewire or liner.

[0022] Still referencing Figure 3The tissue removal element 20 has a central axis CA1 and proximal and distal portions spaced apart from each other along the central axis. As described above, the tissue removal element 20 is operatively coupled to the distal portion of the catheter body, and more specifically, in the illustrated embodiment, the tissue removal element is operatively coupled to the distal portion of the drive shaft 12. The drive shaft 12, by rotation of the actuator 43, causes the tissue removal element 20 to rotate about the central axis CA1 to remove tissue from the body cavity. In the illustrated embodiment, the central axis CA1 is aligned with the longitudinal axis LA of the catheter body 11. Also in the illustrated embodiment, the central axis CA1 extends coaxially with the longitudinal axis of the liner 14 and / or bushing 90 and / or guidewire 26 (when the guidewire is received in the liner). The illustrated tissue removal element 20 includes an abrasive outer surface configured to abrade tissue in the body cavity when the motor 43 rotates the abrasive drill. Therefore, the illustrated tissue removal element 20 can be considered as an abrasive drill. The outer surface is abraded, for example, by coating with diamond abrasive grains, surface etching, etc. In other embodiments, the tissue removal element 20 may include one or more cutting elements, a shredder, a thrombectomy wire, etc., with smooth or serrated cutting edges. The tissue removal element may have other configurations and designs for properly removing tissue from body cavities during its rotation.

[0023] like Figure 3 As shown, the distal portion of the tissue removal element 20 includes a distal end face 100 at the most distal end of the tissue removal element. The distal portion of the shown tissue removal element 20 is generally tapered (e.g., truncated cone), tapering radially distally toward the distal end face 100. The distal end face has a periphery and a diameter extending through a central axis CA1. At least some points on the periphery that are diametrically opposed lie in a plane P1 that is inclined relative to the central axis CA1 of the tissue removal element 20. In this embodiment and other embodiments, all points on the periphery that are diametrically opposed lie in a plane P1 that is inclined relative to the central axis CA1 of the tissue removal element 20. The plane P1 may intersect a plane OP1 orthogonal to the central axis CA1 at an angle A1, which is measured to be from about 5 degrees to about 45 degrees, or from about 10 degrees to about 30 degrees. For example, plane P1 may intersect orthogonal plane OP1 at an angle A1 of approximately 5, 10, 15, 25, 30, 40, or 45 degrees. In one example, angle A1 may be measured as approximately 10 degrees. In the illustrated embodiment, the proximal portion of tissue removal element 20 is substantially symmetrical about the central axis CA1. Specifically, the entire tissue removal element 20 located proximally to the proximal portion of the distal face 100 is circumferentially symmetrical about the central axis CA1. In other words, except for the slope of the distal face 100, tissue removal element 20 may be substantially circumferentially symmetrical about the central axis CA1.

[0024] exist Figures 1 to 6In the illustrated embodiment, the distal surface 100 is generally planar and inclined (e.g., sloped) and lies in a plane P1 inclined relative to the central axis CA1 of the tissue removal element 20. In the illustrated embodiment, the distal surface 100 does not contain abrasive material, but it may include such material. The plane P1 in which the distal surface 100 lies may intersect a plane OP1 orthogonal to the central axis CA1 at an angle A1, which is measured to be from about 5 degrees to about 45 degrees, or from about 10 degrees to about 30 degrees. For example, plane P1 may intersect the orthogonal plane OP at an angle A of about 5 degrees, or 10 degrees, or 15 degrees, or 25 degrees, or 30 degrees, or 40 degrees, or 45 degrees. In one example, angle A1 may be measured to be about 10 degrees.

[0025] The distal opening 102 of the tissue removal element 20 extends through the distal face 100 such that the distal face extends circumferentially around the distal opening. The central axis CA1 of the tissue removal element 20 extends coaxially with the axis of the distal opening 102, such that the distal face 100 is inclined relative to the axis of the distal opening. In the illustrated embodiment, the distal portion of the liner 14 and / or the distal portion of the bearing 90 extends through the distal opening 102. The guidewire 26 extends through the distal opening 102 as it extends along the liner 14. The tissue removal element 20 is configured to rotate concentrically about the guidewire when it is received in the liner 14. In another embodiment, one or both of the liner 14 and the bushing 90 may not extend through the distal opening 102. In yet another embodiment, one or both of the liner 14 and the bushing 90 may be omitted from the catheter 10, thereby allowing the guidewire 26 to extend directly through the distal opening 102.

[0026] refer to Figures 4 to 6 In an exemplary method, the catheter body 12 is inserted into a body cavity (e.g., a blood vessel, such as an artery) to deliver the tissue removal element 20 to the lesion or other tissue to be removed. For example, as the tissue removal element 20 is delivered across the body cavity on the guidewire 26, it may encounter obstacles or "get stuck" on the cavity wall, such as… Figure 4 As shown. It is desired to move the tissue removal element 20 over an obstacle in an efficient manner. The inclined distal face 100 facilitates this bypass movement. The tissue removal element 20 can rotate as it travels along the body cavity. The tissue removal element 20 can rotate continuously or in discrete increments as it travels along the body cavity. When the inclined distal face 100 of the tissue removal element 20 encounters an obstacle, the tissue removal element 20 rotates away from the obstacle due to the rotating inclined distal face (similar to the action of a cam). As a result, as Figure 5 As shown, the contact instability between the distal surface 100 and the obstacle reduces the potential for snagging. Therefore, as Figure 6As shown, the tissue removal element 20 effectively bypasses obstacles. Additionally, the tilted distal face 100 improves the centering of the tissue removal element 20 for ablation and lesion access, while potentially reducing the risk of drill jumps forward during lesion penetration. The tilted distal face 100 also prevents the drill from entering a "false lumen." Once the tissue removal element 20 is delivered to the lesion, it rotates at an appropriate ablation rate to reduce the lesion volume. When the physician has finished using the catheter, it can be withdrawn from the body cavity and unloaded from the guidewire 26 by sliding the catheter proximally along the guidewire. The guidewire 26 used for the ablation process can be left in the body cavity for subsequent procedures.

[0027] refer to Figure 7 Another tissue removal element 220 has a distal face 200 that is convex, such that the distal face is not generally planar. However, as in the first embodiment, the distal face 200 has a periphery and a diameter extending through the central axis CA2. At least some points on the periphery that are diameter-opposite lie in a plane P2 that is inclined relative to the central axis CA2 of the tissue removal element 220. In this and other embodiments, all points on the periphery that are diameter-opposite lie in a plane P2 that is inclined relative to the central axis CA2 of the tissue removal element 220. The plane P2 may intersect a plane OP2 orthogonal to the central axis CA2 at an angle A2, which is measured to be from about 5 degrees to about 45 degrees, or from about 10 degrees to about 30 degrees. For example, the plane P2 may intersect the orthogonal plane OP2 at an angle A2 of about 5 degrees, or 10 degrees, or 15 degrees, or 25 degrees, or 30 degrees, or 40 degrees, or 45 degrees. In one example, the angle A2 may be measured to be about 10 degrees. In the illustrated embodiment, the proximal portion of the tissue removal element 220 is generally symmetrical about the central axis CA2. Specifically, the entire tissue removal element 220 located proximally to the proximal portion of the distal face 200 is circumferentially symmetrical about the central axis CA2. In other words, except for the bevel of the distal face 200, the tissue removal element 220 can be generally circumferentially symmetrical about the central axis CA2. The tissue removal element 20 can be incorporated into a rotary tissue removal catheter 10. The use and benefits of the tissue removal element 220 can be similar to those of the first tissue removal element 20.

[0028] refer to Figure 8Another tissue removal element 320 has a distal face 300 that is convex, such that the distal face is not generally planar. However, as in the first embodiment, the distal face 300 has a periphery and a diameter extending through the central axis CA3. At least some points on the periphery that are diametrically opposed lie in a plane P3 that is inclined relative to the central axis CA3 of the tissue removal element 320. In this and other embodiments, all points on the periphery that are diametrically opposed lie in a plane P3 that is inclined relative to the central axis CA3 of the tissue removal element. The plane P3 may intersect a plane OP3 orthogonal to the central axis CA3 at an angle A3, which is measured to be from about 5 degrees to about 45 degrees, or from about 10 degrees to about 30 degrees. For example, the plane P3 may intersect the orthogonal plane OP3 at an angle A3 of about 5 degrees, or 10 degrees, or 15 degrees, or 25 degrees, or 30 degrees, or 40 degrees, or 45 degrees. In one example, the angle A3 may be measured to be about 10 degrees. In the illustrated embodiment, the proximal portion of the tissue removal element 320 is generally symmetrical about the central axis CA3. Specifically, the entire tissue removal element 320 located proximally to the proximal portion of the distal face 300 is circumferentially symmetrical about the central axis CA3. In other words, except for the bevel of the distal face 300, the tissue removal element 320 can be generally circumferentially symmetrical about the central axis CA3. The tissue removal element 220 can be incorporated into the rotary tissue removal catheter 10. The use and benefits of the tissue removal element 320 can be similar to those of the first tissue removal element 20.

[0029] It should be understood that the aspects disclosed herein can be combined in ways different from those specifically presented in the specification and drawings. It should also be understood that, by way of example, certain actions or events of any process or method described herein may be performed in a different order, or may be added, combined, or omitted entirely (e.g., not all described actions or events may be necessary for implementing these techniques). Furthermore, although some aspects of this disclosure are described for clarity as being performed by a single module or unit, it should be understood that the techniques of this disclosure can be performed by a combination of units or modules associated with, for example, a medical device.

[0030] In one or more examples, the described techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, these functions may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include non-transitory computer-readable media, which corresponds to tangible media such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer).

[0031] Instructions can be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Accordingly, the term "processor" as used herein can refer to any of the above-described structures or any other physical structures suitable for implementing the described techniques. Furthermore, these techniques can be fully implemented in one or more circuit or logic elements.

Claims

1. A tissue removal catheter for removing tissue from a body cavity, the tissue removal catheter comprising: An elongated catheter body having a longitudinal axis and proximal and distal portions spaced apart from each other along the longitudinal axis, the size and shape of the elongated catheter body being configured to be received in the body cavity; A tissue removal element, operatively coupled to the distal portion of the elongated catheter body, the tissue removal element having a central axis and proximal and distal portions spaced apart from each other along the central axis of the tissue removal element. A liner, which is received in the tissue removal element and configured to receive a guidewire within the liner, and A coupling assembly for attaching the tissue removal element to the liner, the coupling assembly including a bushing and at least one bearing ring, the bushing being fixedly attached to the liner, and the at least one bearing ring being attached to the tissue removal element and configured to rotate on the outer surface of the bushing when the tissue removal element rotates about the central axis of the tissue removal element. The tissue removal element is configured to rotate about its central axis to remove tissue from the body cavity. The distal portion of the tissue removal element includes a distal end face at the most distal end of the tissue removal element, the distal end face extending completely around the opening. The distal surface is planar and lies in a plane inclined relative to the central axis of the tissue removal element; The distal opening extends through the distal end face. The distal portion of the bushing extends distally from the distal opening of the distal face of the tissue removal element.

2. The tissue removal catheter as described in claim 1, wherein, The liner has a distal end disposed on the distal side of the distal face of the tissue removal element.

3. The tissue removal catheter as described in claim 2, wherein, The tissue removal element is configured to rotate concentrically on the guidewire when the guidewire is received in the guidewire lumen.

4. The tissue removal catheter as described in claim 3, wherein, The liner extends further through the elongated drive shaft.

5. The tissue removal catheter as described in any one of claims 4, wherein, The central axis of the tissue removal element extends coaxially with the longitudinal axis of the elongated drive shaft.

6. The tissue removal catheter as described in any one of claims 1 to 5, wherein, The outer surface of the tissue removal element is abrasive and is configured to abrade tissue from the body cavity.

7. The tissue removal catheter of claim 6, wherein, The distal portion of the tissue removal element tapers radially outward toward the distal surface.

8. The tissue removal catheter as described in any one of claims 1 to 5, wherein, The elongated catheter body includes a drive shaft extending along the elongated catheter body, wherein the drive shaft is operatively coupled to the tissue removal element and configured to rotate the tissue removal element about its central axis.

9. The tissue removal catheter of claim 8, further comprising a handle and an actuator received in the handle, wherein, The driver is operatively coupled to the drive shaft to allow the driver to rotate selectively.

10. The tissue removal catheter as claimed in any one of claims 1 to 5, wherein, The distal opening in the distal face has an axis, and the diameter of the distal face extends through the axis of the distal opening.

11. The tissue removal catheter as described in any one of claims 1 to 5, wherein, The plane, which is inclined relative to the central axis of the tissue removal element, intersects the plane orthogonal to the central axis at an angle measured to be between 5 and 45 degrees.

12. The tissue removal catheter of claim 11, wherein, The angle measurement is between 10 and 30 degrees.

13. The tissue removal catheter of claim 11, wherein, The angle measurement is 10 degrees.

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