Microvascular polytetrafluoroethylene (Gore-Tex) grafts in the infrarenal rat aorta

To evaluate the use of microvascular prosthetic grafts, the infrarenal aorta in 33 male Sprague-Dawley rats was replaced by an interposition graft of PTFE (polytetrafluoroethylene, Gore-Tex). Three groups of experimental animals were studied: Group A consisted of rats with 7-mm-long grafts, group B consisted of rats with 20-mm-long grafts, and group C consisted of rats with 20-mm-long grafts and ligatures of one patent after varying observation periods (6-92 days, median value 28 days, mean value 49 days). In group B all grafts but one (13/14) were patent (0-201 days, median value 198 days, mean value 118 days). In group C two grafts occluded immediately postoperatively, whereas the remaining six were patent (0-24 days, median and mean values 9 days). Twelve of 13 grafts observed for 3 months or more remained patent. There were no signs of infection. Angiography did not reveal any stenosis in the anastomoses of patent grafts. Light microscopy demonstrated a good adaptation between the grafts and the aorta in all animals. In the short grafts observed for 3 months and in the long grafts observed for 6 months, the luminal surfaces were completely covered by endothelial-like cells. In the occluded graft in group B, a stenosis was demonstrated in one of the anastomoses. This was not found in any other specimen. The results of this study document the possibility of using PTFE grafts of 1 mm diameter in experimental microvascular position.