A 2-PLY ARTIFICIAL BLOOD-VESSEL OF POLYURETHANE AND POLY(L-LACTIDE)

A biodegradable microporous small-caliber vascular prosthesis has been developed that consists of two layers. The inner layer has been made highly antithrombogenic by cross-linking of a mixture of linoleic acid and an aliphatic polyetherurethane with dicumylperoxide. Microporosity was introduced by adding sodiumfluoride crystals of about 5 μm in diameter prior to cross-linking and leaching them out afterwards. The outer ply has been constructed by precipitating a (95/5) physical mixture of polyesterurethane and poly(L-lactide) from solution in the presence of sugar crystals with dimensions in the range 30-90 μm which were removed by exposing the graft to water. The two-ply grafts were tested in vivo by replacing 1 cm of the abdominal aorta of rats. All the grafts remained patent at least up to 1 year and did not exhibit any aneurismal formation. The inner layer was covered with endothelial cells and several layers of smooth muscle cells. © 1990 Steinkopff.