Importance

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Abstract

A conically helically shaped embolization coil (10) for occluding a blood vessel, aneurysm, and the like. The embolization coil includes a continuous platinum-tungsten alloy wire strand (11) wound into a longitudinally extending coil (12) having a plurality of tightly spaced turns (13). The longitudinally extending coil is wound into a conically helically shaped coil (15) with a plurality of radially expanding turns (16). Distal turn (17) of the radially expanding turns has a minor diameter (18) less than a minimum diameter (34) of a vessel (32) of which the embolization is to be positioned therein. Uncompressed proximal turn (19) of the radially expanding turns has a major diameter (20) greater than a maximum diameter (33) of the vessel in which the coil to be positioned. The coil is stress relieved and, in particular, heat treated by heating the coil to a stress relief temperature of the continuous wire strand and cooled to relieve residual stresses formed during the winding of the coil and to minimize the formation of new residual stresses formed during the cool down period of the heat treatment. Thrombogenic fibers (26) are positioned in the tightly spaced turns of the coil to attract thrombus and build up a mass that occludes the vessel lumen. The embolization coil (10) can also include first and second conically helically shaped coils (15, 45) that expand radially in generally opposite directions. The multiple helically shaped coils (15, 45) of the embolization coil accurately and centrally position the embolization coil in the vessel. Each coil acts as an anchor for the other to cause the turns of the coil to make longitudinal contact with each other regardless of the direction of blood flow thereagainst. The longitudinally extending coil (12) of the embolization coil (10) can also be formed to include distal and proximal end turns extending longitudinally from the conically helically shaped coil (15) to better affix and centrally position the embolization coil at the occlusion site.

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First Claim