[Experimental canine hepatic artery embolization with polyvinyl alcohol microspheres].

Polyvinyl alcohol microsphere impregnated with barium sulfate was found to be a good embolizing agent in regard to shape, suspension and distribution in the arteries. Different-phase hepatic artery embolization with microspheres (50 approximately 100 microns, 100 approximately 300 microns) was performed in 20 dogs to evaluate the angiographic and histopathologic changes and hepatic function alterations. Permanent occlusion of the peripheral arterioles was observed on follow-up angiograms one week to six months after embolization. Shrinkage of the embolized segment and focal infarct of the liver were noticed in nearly half of the specimens both grossly and microscopically. The shape and structure of the microspheres were seen unchanged on different-phase specimens, and microspheres as small as 50 microns could reach the corresponding small peripheral arterioles. The liver function alterations were comparable with gelfoam embolization. This study suggested that permanent embolization of small arterioles was possible with such microspheres.