Evaluation of the effect of pharmacologic agents on crush-avulsion arterial injuries: a scanning electron microscopy study

This study was designed to investigate the short-term formation and composition of thrombus occurring at sites of arterial intimal injury in rabbits. Anti-coagulants, platelet anti-aggregation agents, and fibrinolytic agents were evaluated for their influence upon the developing thrombus, utilizing scanning electron microscopy to determine thrombus surface composition. These agents included: heparin, aspirin, dextran 40, streptokinase, and prostacyclin. The results are consistent with the known nature of each of these agents. When two agents were given simultaneously, each acting on different aspects of thrombogenesis (platelets vs. fibrin), the outcome appeared synergistic, with substantial reduction in thrombus accumulation; clear inhibition of both platelet aggregation and fibrin polymerization was noted. These findings support the clinical use of two agents used simultaneously, one inhibiting fibrin strand formation and the other inhibiting platelet adherence aggregation, for the prevention of micro-arterial thrombosis.

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.