Atherectomy apparatus, systems and methods
Described here are devices and methods for performing atherectomies. Generally, the atherectomy devices include a handle, a cutter assembly, and a catheter or catheter assembly therebetween. The cutter assembly includes a cutter housing and a cutter having a first cutting element and a second cutting element, each of which can be rotated relative to the atherectomy device to cut occlusive material.
1. A method for performing an atherectomy comprising:
introducing an atherectomy device into a blood vessel, wherein the atherectomy device comprises a handle, a catheter, and a cutter assembly, wherein the cutter assembly comprises a cutter housing and a cutter configured to rotate within the housing, wherein the cutter comprises at least one helical flute forming a cutting blade having a positive rake angle, wherein the positive rake angle is between 60 degrees and 80 degrees, and wherein the cutter comprises a first cutting element and a second cutting element, wherein the first cutting element has at least a first portion having an outside diameter greater than or equal to an outside diameter of the cutter housing;
advancing the cutter assembly to a targeted region having occlusive material; and
rotating the cutter to cut the occlusive material.
2. The method of claim 1 wherein the positive rake angle is about 70 degrees.
3. The method of claim 1 wherein the first cutting element comprises at least two helical flutes.
4. The method of claim 3 wherein the second cutting element comprises at least two helical flutes.
5. The method of claim 1 wherein at least a portion of the first cutter element extends from an opening in the cutter housing.
6. The method of claim 5 wherein the portion of the first cutter element extending from the opening in the cutter housing has a hemispherical profile.
7. The method of claim 1 wherein the cutting blade has a relief angle less than or equal to about 10 degrees.
8. The method of claim 7 wherein the relief angle is about 0 degrees.
9. The method of claim 1 wherein the cutting blade has a flute angle less than or equal to about 30 degrees.
10. The method of claim 1 wherein the cutting blade has a helix angle between 30 degrees and 60 degrees.