Replacement of the superior vena cava has been the object of intensive and immaginative work in both the experimental and clinical fields. The results reported in the literature, however, are, in the great majority of instances, discouraging. Homologous and heterologous aortic grafts,1,13,16,20 arterial homografts,14,15 caval homografts,6 and pericardial tubes21 were used with variable success. Better results were obtained with simple12 or special2,19 atriocaval anastomoses, but these techniques are not suitable for the replacement of long segments of the superior vena cava, as in the case of invasion of the vessel by tumor. With the advent of plastic vessel substitutes, new enthusiasm arose, but it soon was clear that the answer to the problem had not yet been obtained. Nylon, Ivalon, Orlon, Dacron, Teflon, silicone rubber, and Lucite were the materials used in various studies, but the results were almost uniformly poor.7-10,15,17 Only occasional