The experimental replacement of the inferior caval vein extending from thoracic to abdominal with expanded polytetrafluoroethylene tubular grafts of 15 to 20cm in length were performed in fifteen dogs. Of eleven grafts which had an average pore size of one to two microns, there was one occlusion, a 91 percent patency rate. With a follow up period up to nine and a half months, narrowing of its lumen with thickened neointima was not seen in any animal. Of four grafts with an average pore size of two to four microns, two occlusions were observed, a 50 percent patency rate.
A thin and well attached neointima was recognized in the inner surface. The neointima consisted of collagen and fibrous tissue and was partially lined by endothelial cells. There was no cellular infiltration into the pores of the grafts.
