Comparison of fluoropolymer passivated Dacron and polytetrafluoroethylene grafts in a sheep model.

The search for an optimal prosthetic vascular graft suitable for small vessels continues. The aim of this study was to compare a fluoropolymer passivated Dacron graft with a standard polytetrafluoroethylene graft. A sheep animal model was used. Under general anaesthesia a 5-cm length of 5-mm diameter graft was interposed into the left carotid artery. After an interval of 1, 2 or 3 months the sheep were reanaesthetized and a carotid angiogram performed before harvesting the graft. Graft patency was assessed by macroscopic inspection, angiography and histological examination. Overall, four of eight polytetrafluoroethylene grafts and three of ten fluoropolymer passivated Dacron grafts remained patent with similar patency rates at 1, 2 and 3 months. Histological examination of all available grafts showed evidence of fibrointimal hyperplasia. All but one of the occluded grafts had fibrointimal hyperplasia.