Experimental evaluation of a new transcatheter vascular embolization device in the swine model

To evaluate a new transcatheter device suitable for arterial embolization in an animal model.

A new prototype self-expanding braided embolic device (Embolizor), consisting of nitinol wire strands fixed at either end with platinum-iridium bands and covered with a film of polyethylene, was deployed through 5-F diagnostic catheters into renal artery branches in five swine. Standard stainless-steel spring coils were deployed in other renal branches and served as controls. The animals underwent follow-up selective renal arteriography to determine presence or absence of vessel recanalization or device migration 15-23 days after device deployment. Histopathologic evaluation of target vessels and peripheral renal parenchyma was also performed.

Ten Embolizors and 10 stainless-steel coils were deployed in arteries ranging in size from 1.8 to 3.0 mm in diameter. The Embolizor was easily and precisely deployed. Angiographic evidence of vascular occlusion in the Embolizor group was noted within 30 seconds in eight device deployments and within 5 minutes in two. No early or delayed device migration was noted on follow-up arteriography. In the control group, seven of 10 previously occluded arteries were recanalized. No recanalization was noted in the Embolizor group. Light microscopy revealed evidence of infarction in all specimens examined. Whereas three specimens in the Embolizor group contained occasional giant cells, there were numerous multinucleated giant cells present within the interstices of all control spring coils.

The Embolizor was easily, precisely, and successfully deployed through standard selective diagnostic angiographic catheters. Short-term follow-up demonstrated no recanalization or migration of the device. The Embolizor was shown on histopathologic analysis to have no significant foreign body reaction.