Vascular filter for embolic material

摘要

The filter device, which captures embolic material, runs on a guide wire. The guide wire (12), in one embodiment, has a proximal end, a distal end (14) and a stop (16) near its distal end. The filter device includes an expandable frame (20) of frame struts (21, 23, 25, 27) having a closed, radially compact form (FIG. 4A) and an open, radially expanded form (FIG. 1). The frame, in the radially expanded form, has frame struts forming a pair of facing frustoconical frame structures (6, 28). Filter material (32) is attached to one of the pair of frustoconical frame structures (6). In one embodiment, the guide wire extends through the expandable frame and the expandable frame is freely movable over the guide wire (likewise, the guide wire is freely movable within the frame), both rotatably and longitudinally, except distally beyond the stop near the distal end of the guide wire. In another embodiment, the vascular filter also operates as an embolic material retrieval device (FIGS. 21, 22). This filter device includes a discontinuous loop of memory sheath material (224) having an open loop shape (232, 252) when the loop is not radially restrained in a catheter sheath (208). When the loop is disposed beyond the distal end (210) of the catheter sheath (208), the loop is deployed and forms a discontinuous loop due to the memory characteristic of the loop material. The filter-retrieval device includes a lead line (226) having a proximal end (228) attached to the guide wire and a distal end attached to the discontinuous loop. A substantially conical filter (220) adapted to capture embolic material has an open conical end attached to the discontinuous loop and a conical end point (300) attached to the guide wire. When the loop is disposed outboard of the catheter sheath, the filter unfurls and forms a conical filter trap for embolic material. The filter collapses within the sheath when pulled therein and traps embolic material therein.