Vascular filter with improved strength and flexibilty

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.