Vascular filter with improved strength and flexibility

1. A method for treating a patient having an obstruction on a wall of a first blood vessel through which blood normally flows in a given direction, at a location downstream of a branch point where the first blood vessel and a second blood vessel branch off from a main blood vessel, said method comprising:

blocking blood flow in the main blood vessel at a point upstream of the branch point, with respect to the antegrade direction of blood flow;

inserting into the second blood vessel a first filter adapted to pass blood while trapping debris resulting from removal of the obstruction;

inserting an obstruction removal assembly into the first blood vessel and operating the assembly to at least partially break up the obstruction and produce debris;

after operating the obstruction removal assembly, withdrawing the obstruction removal assembly from the patient's body and then inserting into the first blood vessel a second filter adapted to pass blood while trapping debris that results from removal of the obstruction;

after inserting the first and second filters, restoring blood flow in the main blood vessel; and

withdrawing the first and second filters from the patient's body together with trapped debris.

2. The method of claim 1 , wherein the first blood vessel is an internal carotid artery and the second blood vessel is an external carotid artery.

3. The method of claim 2 wherein the main blood vessel is a common carotid artery and said step of blocking blood flow is performed in the common carotid artery.

4. The method of claim 2 wherein said step of inserting a removal device obstruction comprises:

introducing a guide wire through a guide catheter into the first blood vessel; and

then introducing the removal assembly over the guide wire to the site of the obstruction.

5. The method of claim 1 , further comprising, during a time when blood flow in the main blood vessel is blocked, applying suction to a region that contains debris produced from the obstruction.

6. The method of claim 5 , wherein said step of applying suction is carried by operating a suction device located outside of the patient's body and placing the suction device in communication, through a tube, with the region that contains debris produced from the obstruction.