Scanning electron microscopy of crush/avulsion arterial trauma:effect of heparin and aspirin administration

A model of vascular trauma and subsequent reanastomosis with poor postoperative likelihood of patency was developed in the rat femoral artery. Patency rates were significantly improved with intravenous heparin, intragastric aspirin, and both agents together. Heparin yielded higher patency than aspirin. Intimal surfaces of the vessels at various postoperative intervals were observed with the scanning electron microscope. More fibrin accumulation was seen in the aspirin-treated animals, while more platelet aggregation was found in the heparin-treated group. Both platelet aggregation and fibrin strand development appeared retarded with both agents administered. All groups demonstrated good healing of the ruptured intimal surfaces, beginning at 2 days postoperatively. It is concluded that fibrin strand development is a more significant factor in microvascular occlusion than platelet aggregation.