Helical embolization coil

TLDR: A conically helically shaped embolization coil as mentioned in this paper is used for occluding a blood vessel, aneurysm, and the like, and is wound into a longitudinally extending coil with a plurality of tightly spaced turns.

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) that has spacing that increases proximally from the distal end (29) of the coil. 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 conically helically shaped coil and particular diameter ensure that the coil is precisely positioned in a vessel lumen without longitudinal displacement of the delivery catheter. 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.