Venous prostheses: improved patency with external stents.

A uniformly successful prosthesis for replacement in the venous system has not been developed. This study assesses the effect of external stents on the patency of polytetrafluoroethylene (PTFE) grafts in the infrarenal vena cava. Under general anesthesia, 21 mongrel dogs underwent midline laparotomy. The infrarenal vena cava was resected and replaced by a standard segment (8 cm X 10 mm) of stented PTFE (12 dogs) and nonstented PTFE (9 dogs). Patency was assessed by contrast venography and the results compared between the two groups. The 7-, 30-, and 90-day patency was 12/12, 10/12, and 9/12, respectively, for stented PTFE and 6/9, 2/9, and 2/9, respectively, for nonstented PTFE. The patency of externally stented PTFE at 30 and 90 days was significantly better than grafts fashioned from PTFE alone (P less than 0.05 by chi-square analysis). These data demonstrate that external stenting improves the early patency of PTFE prostheses in the infrarenal vena cava. Consideration should be given to the clinical use of externally stented PTFE when prosthetic replacement in the venous system is required.