Method and apparatus for increasing rotational amplitude of abrasive element on high-speed rotational atherectomy device

Abstract

A high-speed atherectomy device is disclosed, for abrading a blockage (stenosis) in the interior of a lumen (artery). The device uses a rapidly rotating drive shaft that includes an eccentric abrasive element that has its center of mass laterally offset from the rotational axis of the drive shaft. As the drive shaft rotates, centrifugal force drives the eccentric abrasive element outward, so that it traces an abrading diameter at high rotational speeds that is larger than its rest diameter. The drive shaft includes counterweights on both sides of the abrasive element, which may stabilize operation at high rotational speeds. In some cases, the counterweights are also eccentric, with their centers of mass laterally offset from the rotational axis in the opposite direction as that of the abrasive element. The counterweights are longitudinally separated from the abrasive element, and in some cases, the separations are adjustable and/or controllable. In some cases, the guide wire may be retracted prior to or during the high-speed rotation of the drive shaft, with the retraction being to the distal counterweight, the abrasive element, the proximal counterweight, or beyond the proximal counterweight.