Patent ID: 6843797

Claim:
A method for opening a lumen in an occluded blood vessel portion of a living being's vascular system located downstream of a first blood vessel portion from which blood will flow to the occluded blood vessel portion, the occluded blood vessel portion being occluded by an occlusive material and being located downstream of a patent blood vessel portion, said method comprising: (a) providing a catheter, an instrument and debris extraction means, said catheter having a distal end portion, said instrument having a working head, (b) locating said catheter so that a portion of it extends into the being's vascular system, extending said instrument through said catheter to form a passageway therebetween, and with said working head being located adjacent said distal end of said catheter, (c) operating said working head on the occlusive material in the interior of the occluded blood vessel portion to open a lumen for the flow of blood therethrough to said second blood vessel portion, whereupon some debris may be produced from the occlusive material by the operation of said working head, (d) causing said debris extraction means to introduce an infusate liquid at a first flow rate adjacent said working head, and (e) causing said debris extraction means to withdraw said liquid at a second and higher flow rate to create a differential flow adjacent said working head, whereupon debris produced by the operation of said working head is withdrawn through said passageway for collection remote from the occluded blood vessel portion.