Atherectomy apparatus, systems and methods
Described here are devices and methods for performing atherectomies. Generally, the atherectomy devices may include a handle, a cutter assembly, and a catheter or catheter assembly therebetween. The cutter assembly may include a cutter housing and a cutter having a first cutting element and a second cutting element, each of which may be rotated relative to the atherectomy device to cut occlusive material.
1. A device for removing occlusive material from a vessel comprising:
a handle;
a catheter; and
a cutter assembly comprising a cutter housing and a cutter having a rotational axis, the cutter configured to rotate within the housing, the cutter comprising at least one helical flute forming a cutting blade having a most radially distant edge and an inner face;
wherein the cutting blade has a positive rake angle of at least 20 degrees;
wherein the rake angle is defined as an angle measured between (i) a radius drawn from the rotational axis to the most radially distant edge of the cutting blade and (ii) a tangent drawn from the inner face of the cutting blade.
2. The device of claim 1 wherein the positive rake angle is between 60 degrees and 80 degrees.
3. The device of claim 2 wherein the positive rake angle is 70 degrees.
4. The device of claim 1 wherein the cutter comprises a first cutting element and a second cutting element.
5. The device of claim 4 wherein the first cutting element comprises at least two helical flutes.
6. The device of claim 5 wherein the cutter further comprises a second cutting element, and wherein the second cutting element comprises at least two helical flutes.
7. The device of claim 5 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.
8. The device of claim 5 wherein at least a portion of the first cutter element extends from an opening in the cutter housing.
9. The device of claim 8 wherein the portion of the first cutter element extending from the opening in the cutter housing has a hemispherical profile.
10. The device of claim 1 wherein the cutting blade has a relief angle less than or equal to 10 degrees.
11. The device of claim 10 wherein the relief angle is about 0 degrees.
12. The device of claim 1 wherein the cutting blade has a flute angle less than or equal to 30 degrees.
13. The device of claim 1 wherein the cutting blade has a helix angle between 30 degrees and 60 degrees.