Multi-material abrading head for atherectomy devices having laterally displaced center of mass

摘要

An abrading head for a high-speed rotation atherectomy device is disclosed. The head has its center of mass laterally displaced from the rotational axis of the drive shaft. As the drive shaft spins, centrifugal force forces the abrading head radially outward. At high speeds, and the abrasive portion of the head may subtend an abrading cylinder larger than at low speeds or at rest. The abrading head has two components, each having a different density. The connection portion may be an incomplete cylinder, which fastens onto the drive shaft, and may be a relatively low density metal, such as stainless steel. The eccentric portion may be a relatively high density metal, such as tungsten or tantalum, and is attached to the connection portion. The eccentric portion has all or most of its mass on one side of the rotation axis of the drive shaft, providing a larger separation between the center of mass of the abrading head and the rotational axis of the drive shaft than if the abrading head were made from only one material.

主权项

1. A high-speed rotational atherectomy device for opening a stenosis in an artery having a given diameter, comprising: a guide wire having a maximum diameter less than the diameter of the artery; a flexible, elongated, rotatable drive shaft advanceable over the guide wire, the drive shaft having a rotational axis and having a controllable drive shaft rotation speed; at least one eccentric abrading head comprising a geometric eccentricity and a center of mass radially offset from the rotational axis of the drive shaft, wherein the at least one eccentric abrading head is attached to the drive shaft, and comprising:
a connecting portion fixedly attached to and at least partially surrounding the drive shaft, the connecting portion attached to the drive shaft and being formed from a connecting portion material, wherein the connecting portion is an incomplete cylinder having a center of mass that is concentric with the rotational axis of the drive shaft; an eccentric portion fixedly attached to and at least partially surrounding the connecting portion and formed from an eccentric portion material different from the connecting portion material, the eccentric portion including a proximal portion, a central portion adjacent to the proximal portion, and a distal portion adjacent to the central portion opposite the proximal portion; and an abrasive portion disposed on an exterior surface of the central portion; wherein the eccentric portion material is more dense than the connecting portion material, and wherein the center of mass of the at least one eccentric abrading head is radially offset from the rotational axis of the drive shaft as a result of a combination of the geometric eccentricity of the at least one eccentric abrading head and the more dense material of the eccentric portion.