Atherectomy catheter with laterally-displaceable tip
Described herein are atherectomy catheters, systems and methods that include a distal tip region that may be moved laterally so that its long axis is parallel with the long axis of the main catheter body axis. Displacing the distal tip region laterally out of the main catheter body axis exposes an annular blade and opens a passageway for cut tissue to enter a storage region within the catheter. The annular blade may be internally coupled to a drive shaft that rotates the blade, and thus the exposed blade edge may have the same crossing profile (OD) as the rest of the distal end region of the catheter. Also described herein are gear-driven atherectomy devices that may use a cable drive shaft to actuate the annular blade. Both push-to-cut and pull-to-cut variations are described, as are methods for cutting tissue and systems including these atherectomy catheters.
1. An atherectomy catheter device for cutting tissue in a vessel, the device comprising:
an elongate, flexible catheter body having a proximal end and a distal end and a longitudinal axis;
an elongate displaceable distal tip assembly;
a rotatable annular cutting ring between the distal end of the catheter body and the distal tip assembly;
a handle attached to the proximal end of the catheter, the handle including a control that is configured to expose a cutting edge of the annular cutting ring by displacing the distal tip assembly from a closed configuration in which the distal tip assembly is in-line with the catheter body to an open configuration in which the distal tip assembly is off-axis from the catheter body, wherein the rotatable annular cutting ring remains in-line with the distal end of the catheter body when the distal tip assembly is displaced and forms a distal cutting edge at the distal end of the catheter body;
a balloon mounted on a circumference of the catheter body approximately 180 degrees from an exposed portion of the distal cutting edge, the balloon configured to inflate to urge the exposed portion of the distal cutting edge into the tissue; and
an Optical Coherence Tomography (OCT) imaging subassembly comprising a fiber extending the length of the catheter body, a distal end of the fiber fixed in a position that is proximal to the distal cutting edge,
wherein the OCT imaging subassembly is configured to be rotated to obtain angular survey images of the vessel.
2. The device of claim 1 , further comprising a drive shaft extending along the length of the catheter body, wherein axial movement of the driveshaft moves the distal tip assembly between the open and closed configurations.
3. The device of claim 2 , wherein the drive shaft comprises a cable drive shaft having a distal gear configured to drive rotation of the cutting ring.
4. The device of claim 2 , wherein the drive shaft is directly connected to the annular cutting ring.
5. The device of claim 2 , wherein the drive shaft comprises a hollow tubular drive shaft having a hollow lumen, the optical fiber extending within the hollow lumen.
6. The device of claim 1 , wherein the annular cutting ring comprises internal gear teeth configured to mate with a drive shaft to rotate the cutting ring.
7. The device of claim 1 , further comprising a guidewire lumen extending the length of the catheter.
8. The device of claim 1 , wherein the annular cutting ring forms an outer surface of the catheter in both the closed and open configurations.
9. The device of claim 1 , further comprising an internal tissue collection region configured to receive tissue cut by the annular cutting ring.
10. The device of claim 9 , wherein the tissue collection region is located within the distal tip assembly.
11. The device of claim 9 , wherein the tissue collection region is located within the catheter body.
12. An atherectomy catheter device for cutting tissue having a displaceable tip, the device comprising:
an elongate catheter body having a longitudinal axis;
a displaceable distal tip assembly attached to a distal end of the catheter body;
an annular cutting ring between the catheter body and the distal tip assembly;
an inflatable element near the distal end of the catheter body configured to displace the distal tip assembly relative to the elongate catheter body when inflated; and
a handle attached to the elongate catheter body, the handle including a control that is configured to switch the distal tip assembly between a closed configuration, in which the distal tip assembly is in-line with the catheter body and the cutter is protected by the distal tip assembly, and an open configuration, in which the distal tip assembly is displaced from the catheter body, by inflating the inflatable element to move the distal tip assembly away from the distal end of the catheter body to expose a cutting edge of the annular cutting ring, wherein the annular cutting ring remains in-line with the distal end of the catheter body when the distal tip is displaced and forms an exposed distal cutting edge at the distal end of the catheter body, further wherein the inflatable element is positioned approximately 180 degrees from the exposed distal cutting edge when the distal tip is displaced.
13. The device of claim 12 , further comprising a drive shaft extending along the length of the catheter body.
14. The device of claim 13 , wherein the drive shaft comprises a cable drive shaft having a distal gear configured to drive rotation of the cutting ring.
15. The device of claim 13 , wherein the drive shaft is directly connected to the annular cutting ring.
16. The device of claim 13 , wherein the drive shaft comprises a hollow tubular drive shaft.
17. The device of claim 12 , wherein the annular cutting ring comprises internal gear teeth configured to mate with a drive shaft to rotate the cutting ring.
18. The device of claim 12 , further comprising a guidewire lumen extending the length of the catheter.
19. The device of claim 12 , wherein the annular cutting ring forms an outer surface of the catheter in both the closed and open configurations.
20. The device of claim 12 , further comprising an internal tissue collection region configured to receive tissue cut by the annular cutting ring.
21. The device of claim 20 , wherein the tissue collection region is located within the distal tip assembly.
22. The device of claim 20 , wherein the tissue collection region is located within the catheter body.
23. The device of claim 12 , further comprising an OCT imaging subassembly.
24. The device of claim 23 , wherein the OCT imaging subassembly comprises a fiber optic extending the length of the catheter body.
25. The device of claim 23 , wherein the OCT imaging assembly comprises a side-facing OCT emitting element fixed proximal to the annular cutting ring.
26. The device of claim 23 , wherein the OCT imaging assembly comprises a side-facing OCT emitting element fixed distally to the annular cutting ring.