Scanning electron microscopy evaluation of porous and nonporous arterial substitutes

The fate of two different kinds of new small arterial substitutes, porous and nonporous, has been compared, particularly with regard to the structure of the luminal surface. Twenty-eight weavenit Dacron pyrolytic carbon coated grafts and 28 glutaraldehyde-tanned human umbilical vein segments were implanted into the carotid arteries of dogs. Grafts were removed at intervals, from ten to 120 days after implantation, and examined by scanning electron microscopy. The cumulative patency rate was 96.4 per cent for Dacron and 85.7 per cent for umbilical vein grafts. Ten days after implantation, the Dacron grafts were uniformly covered by a thin thrombus layer, while the umbilical vein grafts showed a thin network of fibrin on the central portion of the luminal surface of the graft and thrombotic deposits at the anastomoses. Thirty days after implantation, both types of prostheses showed the development of a thin fibrous tissue layer on the inner surface. Finally, at 120 days, an endothelial lining was observed.