Problems in the construction of a small diameter graft.

Hyperplasia at the graft host artery anastomosis is probably the commonest cause of intermediate and late failure and is seen most frequently and most severely in small diameter grafts. An arterial substitute with an internal diameter of less than 4 mm which can maintain patency in a flow rate not in excess of 50 cc per minute is the sought after graft. Contributing to the formation of this hyperplastic lesion are activated platelets, activated monocytes, dedifferentiated endothelial cells, and probably other elements which under these circumstances of activation produce smooth muscle cell and other mitogens. A multidisciplinary approach utilizing the information from polymer chemistry, fluid engineering, cell biology, and the essentials of thrombosis is required.