Atherectomy devices and methods
This document describes rotational atherectomy devices and systems for removing or reducing stenotic lesions in blood vessels by rotating an abrasive element within the vessel to partially or completely remove the stenotic lesion material.
1. A rotational atherectomy device, comprising:
an elongate flexible drive shaft comprising helically wound metallic coil having a constant outer diameter of about 0.020 inches to about 0.100 inches;
a distal metallic concentric element having a center of mass aligned with a longitudinal axis of the drive shaft and being fixedly mounted to the drive shaft such that a distal tail of the helically wound metallic coil extends distally of the distal metallic concentric element; and
an array of at least three eccentric abrasive burrs having a spherical or ellipsoid shape with an abrasive outer surface and being fixedly mounted to the drive shaft at a position spaced proximal from the distal metallic concentric element such that a center of mass of each of the at least three eccentric abrasive burrs is offset from the longitudinal axis while contemporaneously the center of mass of the distal metallic concentric element is aligned with the longitudinal axis,
wherein the array of at least three spherical or ellipsoid eccentric abrasive burrs comprises at least: a middle abrasive burr having the spherical or ellipsoid shape, a proximal-most abrasive burr having the spherical or ellipsoid shape, and a distal-most abrasive burr having the spherical or ellipsoid shape, wherein the middle abrasive burr in the array has a maximum outer diameter that is greater than both a maximum outer diameter of the proximal-most abrasive burr in the array and a maximum outer diameter of the distal-most abrasive burr in the array.
2. The device of claim 1 , wherein the distal metallic concentric element has a cylindrical shape that defines an inner diameter and the distal metallic concentric element is fixed along the inner diameter to the helically wound metallic coil of the drive shaft.
3. The device of claim 1 , wherein the coil of the drive shaft defines a central lumen extending along the longitudinal axis that is configured to receive a guidewire fully withdrawable into the central lumen.
4. The device of claim 1 , wherein the drive shaft comprises a fluid-impermeable material along at least a portion of the coil.
5. The device of claim 1 , wherein the distal metallic concentric element comprises a coating along its outer surface.
6. The device of claim 1 , wherein the at least three eccentric abrasive burrs in the array are spaced apart from one another by an element spacing distance, and the distal metallic concentric element is distally spaced apart from the distal-most abrasive burr in the array by a distal separation distance that is greater than the element spacing distance.
7. The device of claim 1 , wherein the eccentric abrasive burrs of the array of at least three eccentric abrasive burrs are positioned adjacent to one another along the drive shaft.
8. The device of claim 1 , wherein the helically wound metallic coil is configured to transmit torque and wherein the distal metallic concentric element comprises a hollow metallic cylinder with an inner diameter that is fixed along the inner diameter of the hollow metallic cylinder to the outer diameter of the helically wound metallic coil.
9. The device of claim 1 , wherein the drive shaft comprises a coating on the outer diameter of the drive shaft.
10. The device of claim 1 , further comprising a proximal metallic concentric element fixed to the drive shaft.
11. The device of claim 1 , wherein the center of mass of each of the at least three eccentric abrasive burrs is offset from the longitudinal axis such that, in response to rotation of the drive shaft about an axis of rotation at 20,000 rpm to 160,000 rpm, the array of at least three eccentric abrasive burrs moves in an orbital path that is larger than a maximum diameter of a rotational path of the distal metallic concentric element.
12. The device of claim 11 , wherein in response to the rotation of the drive shaft about the axis of rotation, the array of at least three eccentric abrasive burrs, the distal metallic concentric element, and the distal tail of the helically wound metallic coil rotate together such that the array of at least three eccentric abrasive burrs moves in the orbital path while the distal tail of the helically wound metallic coil rotates in substantially stable axial alignment with the axis of rotation.
13. The device of claim 1 , wherein the proximal-most spherical abrasive burr in the array has a maximum outer diameter smaller than the middle spherical abrasive burr in the array.
14. The device of claim 13 , wherein the distal-most spherical abrasive burr in the array has a maximum outer diameter smaller than the middle spherical abrasive burr in the array.
15. The device of claim 1 , wherein the array of at least three eccentric abrasive burrs comprises five eccentric abrasive burrs having the spherical or ellipsoid shape positioned along the drive shaft.
16. The device of claim 15 , wherein the five eccentric abrasive burrs are positioned adjacent to one another along the coil.