Patent ID: 8852219

Claim:
A medical device for removal of obstructive material from a target site in a body lumen or cavity comprising an operating head operably connected to a rotatable drive shaft and positioned in proximity to a distal end of an elongated catheter, the operating head including a support and a plurality of cutting blades extending from the support and arranged radially around a central axis of the operating head, wherein a cross-section of at least one of the blades has a stepped blade cutter configuration having a leading edge cutting surface adjacent or in proximity to a shoulder region which is adjacent to a leading surface, the shoulder region being positioned between the leading edge cutting surface and the leading surface, wherein the shoulder region has a width that is greater than a height of the leading edge cutting surface along substantially its entire interface and forms an angle with the plane of the leading edge cutting surface of from about 60° to about 120°, and wherein the leading surface and the shoulder region are generally atraumatic to tissue, while the leading edge cutting surface exerts a material removal action.