Expanded polytetrafluoroethylene grafts for small artery replacement

Twenty vascular grafts of expanded polytetrafluoroethylene with a 1.5 mm. internal diameter and a 4.0 cm. length, were placed in the femoral arteries of dogs. The animals, divided into two groups, with and without pluronic F 68, were sacrificed two weeks after surgery. The patency rate was 33.3% (2/6) and 21.5% (3/14), which was not statistically significant. One factor contributing to the occlusion of the grafts were excessive proliferation of granulation tissue due to early formation of the thrombus. Histological findings showed that the pseudointima was almost complete, although it was only about 0.114 mm. thick at the anastomotic line.