High compliance vascular grafts based on semi-interpenetrating networks.

Current synthetic vascular grafts have poor patency rates in small diameter applications (<6 mm) due to intimal hyperplasia arising from a compliance mismatch between the graft and native vasculature. Enormous efforts have focused on improving biomechanical properties; however, polymeric grafts are often constrained by an inverse relationship between burst pressure and compliance. We have developed a new, semi-interpenetrating network (semi-IPN) approach to improve compliance without sacrificing burst pressure. The effects of heat treatment on graft morphology, fiber architecture, and resultant biomechanical properties are presented. In addition, biomechanical properties after equilibration at physiological temperature were investigated in relation to polyurethane microstructure to better predict