Expanded microporous polytetrafluoroethylene as canine arterial bypass or replacement graft.

Expanded microporous polytetrafluoroethylene (PTFE) has been used experimentally and clinically for small-vessel bypass or replacement grafting; the results vary widely. This study assessed short (4--cm) femoral and carotid artery replacement PTFE grafts and longer (12--cm) femoral artery bypass PTFE grafts that crossed a flexion crease. Pore size at the blood-graft interface ranged from 10 to 30 mu. At the end of three months, overall patency rate was 22%. No long bypass grafts remained patent. The pore size and type of anastomosis did not affect patency. The occlusion was always thrombotic, associated with fibrin at the suture line. Nine of the 20 short carotid grafts (45%) and five of 22 short femoral grafts (22%) remained patent. These poor results indicate that further experimental studies are needed before PTFE is used clinically when an alternative exists.