Experimental models for evaluating antithrombotic therapies in replantation microsurgery.

A variety of anticoagulation and antiplatelet aggregation agents are in use clinically, and in applications to microvascular surgery, a clear choice for the most effective therapy has not been determined. Models of vascular trauma combined with microvascular anastomosis have been developed for comparing the efficacy of these agents in maintaining vascular patency. In a rat model of microvascular thrombosis, heparin effectively prevents occlusion in both arteries and veins, at clinical levels of administration. Aspirin helps prevent thrombosis, but not as well as heparin. These results support the beneficial effect of antithrombotic drug therapies, and suggest a more potent role of the heparin-inhibited fibrin clot over platelet aggregation in creating thrombotic occlusion of small vessels.