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. A method of performing an atherectomy to remove tissue from within a vessel lumen using an atherectomy catheter, the method comprising:
advancing the atherectomy catheter within a vessel lumen, the atherectomy catheter including an elongate catheter body with a longitudinal axis, a driveshaft extending along a length of the elongate catheter body and a displaceable distal tip assembly having an imaging window therein;
imaging the vessel lumen using an Optical Coherence Tomography (OCT) sensor comprising a fiber extending along the length of the elongate catheter body, a distal end of the fiber attached to the catheter in a position proximal to a distal cutting edge of an annular cutting ring of the atherectomy catheter;
simultaneously rotating the OCT sensor and rotating the annular cutting ring with the driveshaft, the rotations performed relative to the longitudinal axis of the catheter body, to obtain angular survey images of the vessel lumen through the imaging window;
axially moving the driveshaft to expose the cutting edge of the annular cutting ring of the atherectomy catheter by displacing the distal tip assembly off-axis from the longitudinal axis of the catheter body, wherein the annular cutting ring remains in-line with the distal end of the catheter body when the distal tip assembly is displaced to expose the cutting edge; and
driving the cutting edge against a wall of the vessel lumen to remove tissue.
2. The method of claim 1 , further comprising rotating the annular cutting ring while driving it against the wall of the vessel lumen.
3. The method of claim 1 , wherein the driving step comprises pushing the catheter distally.
4. The method of claim 1 , wherein the driving step comprises pulling the catheter proximally.
5. The method of claim 1 , further comprising collecting cut tissue within an opening of the atherectomy catheter.