Fabrication of Polyurethane-based Artificial Blood Vessel Implants

In patients suffering from peripheral arterial disease; where vessels narrow and/or lose their efficiency and kidney failure; where hemodialysis is performed through an arteriovenous (AV) fistula that connects an artery to a vein, to purify blood, three types of surgical treatment; namely angioplasty, endarterectomy, and bypass grafting are vigorously considered. In cases like acute artery stenosis and multi-focal stenosis, a bypass is generally used. In addition, burns can damage blood vessels and cause fluid loss. This may result in low blood volume (hypovolemia) and in this case a bypass graft surgery is inevitable. However, in some cases, patients lack appropriate vessels for autologous grafting (autologous grafting includes grafting of a tissue from one site to another site of the same body). Furthermore, in autologous transplantation, a patient undergoes two surgeries simultaneously. In this respect, researchers have focused on designing artificial blood vessels as vascular implants. A class of materials that is highly regarded promising is polyurethanes, due to a number of outstanding properties including blood compatibility, biocompatibility, and most importantly, capability to tailor desirable properties. This report focuses on application of polyurethanes as artificial blood vessels while the impact of key parameters such as design of the polyurethane backbone, surface modification, and bulk modification, on the polymer key properties including: toxicity, endothelialization, and platelets adhesion are reviewed