Small diameter blood vessel prostheses from blends of polyethylene oxide and polypropylene oxide

Studies on the relationship between blood platelet adhesion and type and amount of polyether segments in copolyetherurethanes report a reduced platelet adhesion with increasing polyether content. We therefore assumed that combinations of polyethylene oxide (PEO) and polypropylene oxide (PPOX) might give materials with a good blood compatibility. Water-soluble PEO was attached to PPOX by u.v.-initiated crosslinking. Films were tested for hydrophilicity, mechanical properties, protein adsorption and blood compatibility. The hydrophilicity was determined by swelling experiments. A compromise between hydrophilicity (PEO) and mechanical strength (PPOX) was met at a swelling of 0.5 (PPOX/PEO ratio: 90/10). In protein adsorption studies only small amounts of adsorbed proteins were found. Three blood material interaction in vitro tests gave good results: a low platelet adhesion and kallikrein generation and a high APTT value. Porous tubings (inner diameter 1.3 mm) were fabricated, by spinning from solution, for implantation in the abdominal aorta of rats. Stress-strain diagrams were comparable to those reported for natural blood vessels.