In vitro and in vivo biodurability of a compliant microporous vascular graft.

Polyurethanes have unique mechanical and biologic properties that make them ideal for many implantable devices. However, certain polyurethanes are affected by some in vivo degradation mechanisms. For example, poly(ester)urethanes are subject to hydrolytic degradation and are no longer used in long-term implanted devices. Poly(ether)urethanes while hydrolytically stable, are subject to oxidative degradation in several forms, including environmental stress cracking and metal ion oxidation. We have developed a second-generation poly(carbonate)urethane with superior biostability. This material has been fabricated by our patented method into small diameter microporous vascular grafts. We evidenced the biodurability of our vascular graft by in vitro qualification tests which compared the poly(carbonate)urethane with a traditional poly(ether)urethane. This poly(carbonate)urethane graft has also proven to be biodurable in in vivo experimental implants up to twenty months duration with no evidence of hydrolysis or environmental stress cracking (ESC).