THE NATURE OF THROMBOSIS INDUCED BY PLATINUM AND TUNGSTEN COILS IN SACCULAR ANEURYSMS

PURPOSE: To compare the efficacy and biocompatability of electrolytic and mechanically detachable embolization coils of two metal types, MET HODS: Experimental saccular aneurysms in pigs were used to assess embo lization induced by platinum or tungsten coils. Longitudinal angiograp hic and histologic studies were performed on treated and untreated (co ntrol) aneurysms to compare thrombosis and cellular responses after em bolization with electrolytically detachable platinum coils and with me chanically detached tungsten coils. RESULTS: Fewer tungsten than plati num coils were needed to induce thrombosis, The inflammatory response within the aneurysmal lumen was more florid in embolized aneurysms tha n in control aneurysms. No difference was found in the timing or exten t of accumulation of eosinophils, lymphocytes, or polymorphs between t he two coils used. Giant cell responses were more marked in treated an eurysms; tungsten coils more than platinum coils. The amount of collag en and fibrosis present increased over the study period and was simila r in treated and control aneurysms. CONCLUSION: The coil type influenc ed the initial cellular response but had little effect on the rate or degree to which blood clot within the aneurysm was replaced by fibrous tissue.