History of Vascular Graft Development

Synthetic vascular grafts developed beginning in the 1950s as a consequence of observations of Voorhees in the late 1940s and early 1950s that a synthetic fabric made from Vinyon “N” became coated with a smooth, relatively nonthrombogenic surface when implanted in the dog's aorta. Earlier efforts to modify human and other mammalian aortas — denaturation, freeze drying, and the like, were unsuccessful because of gradual breakdown and aneurysm formation. Desirable qualities of a graft included that it was bloodtight after interstitial clotting, would have an adequate pore size to permit fibroblast reorganization, be conformable to the tissues around it, and would be biologically inert. Great success was achieved with such grafts in large diameter arteries with high flow rates and low resistance, but satisfactory grafts for smaller vessels have been disappointing because of incomplete healing in the human. All synthetic grafts and modified grafts of biologic origin fail to develop an endothelial lining. Anastomotic hyperplasia, chiefly of smooth muscle cells, gradually reduces flow, leading to retrograde thrombosis and failure. For better grafts to be developed, a greater understanding of the cellular, humoral, and enzymatic aspects involved in graft/host healing mechanisms in the circulating blood/graft interface is necessary.