Experimental Study of the Antithrombogenic Behaviour of PEtU-PDMS Small Diameter Vascular Grafts

Cardiovascular diseases are increasing as the average age of elderly population continues to grow. For this reason coronary and peripheral vascular bypass grafting is performed more than 600,000 times annually in the United States and Europe. Autogenous saphenous vein is the conduit of choice for use as bypass graft both in peripheral and cardiac procedures, but it is not without significant constraints and complications. Replacement of arteries with purely synthetic prosthesis, as expanded polytetrafluoroethylene (ePTFE) and polyethylene terephtalate (PET), leads to failure when small-diameter (less than 6 mm) or low-flow locations are concerned. This is due to thrombogenicity of the internal graft surface and intimal hyperplasia around anastomosis caused by a compliance mismatch between graft and native blood vessel. In this study a silicone-based elastomeric material was processed to realjse small diameter vascular grafts (5 mm). The innovative idea was to combine the excellent hemocompatibility of a particular reactive polydimethylsiloxanc (PDMS) with the optimal physical-mechanical characteristic of an aromatic poly(ether)urethane (PEtU).