Experimental arteriovenous fistulas: treatment with silicone-covered metallic stents.

PURPOSE To determine the efficacy of silicone-covered metallic stents in the treatment of experimentally created carotid-jugular fistulas. METHODS Carotid-jugular fistulas were surgically constructed in six mongrel dogs. Silicone-coated, self-expanding metallic stents were placed across the fistula holes within the carotid artery, and carotid angiography was performed before, immediately after, and 4 and 8 weeks after stent placement. Fistula specimens were resected 2 months after stent placement and analyzed by means of gross and light microscopy. RESULTS Angiography revealed complete closure of all fistulas immediately after stent deployment. The fistulas remained closed and all carotid arteries remained patent. Marked stenosis within the carotid lumen was seen along the proximal and distal ends of the stents. Gross and micropathologic specimens of the carotid-jugular fistulas revealed fibrous connective tissue and collagen across the fistula holes. Proliferative fibrous connective tissue, collagen, and fibromyoblasts were located at either end of the stents. The wires of the stents indented the intraluminal surface of the carotid arteries. CONCLUSIONS Silicone-covered stents were effective in closing all experimentally created carotid-jugular fistulas. With further refinements and variations in technique, covered stents may prove a viable alternative to current endovascular devices.