US Patent 7241305 Apparatus for trapping emboli

A filter for filtering micro-emboli from a patient's blood during an angioplasty procedure is disclosed which comprises a plurality of curved wires connected to a rod between a first connector fixed with respect to the rod and a second connector slidingly mounted on the rod. Two layers of filter material are connected to opposite sides of the wires, and each layer includes perforations which are offset from the perforations in the other layer. When the rod and the wires are disposed within a catheter, the inner wall of the catheter compresses the wires toward the rod and when the rod is extended from the catheter, the wires resume their curved shape and pull the sliding connector along the rod toward the fixed connector.