Tables 36-1 through 36-5 list 54 agents that have been investigated for some aspect of their effects on vascular patency and tissue survival. The first four tables divide agents according to their principal reported mechanism, and the fifth table lists agents investigated for effects detrimental to microsurgical procedures. The entry for each agent includes a brief description of its action, its reported experimental and clinical effects, and the doses and courses within which it has been administered.

Like previous efforts,46,60,61 this attempt to classify microsurgical pharmacology acknowledges that the drugs themselves have multiple effects, that they act within a complicated biologic situation, and that conclusive experimental and clinical studies have not been reported. The results of this classification are therefore not themselves conclusive. They are descriptive of the current theory and use of these agents in experimental and clinical microsurgery.

ANTIPLATELET AND ANTICOAGULATING AGENTS (TABLE 36-1)

Aspirin is used clinically in all aspects of microsurgery as a supressor of platelet aggregation. l,32,36,40,62 Although the evidence for aspirin's specific efficacy in microsurgery is circumstantial, published animal and human studies document aspirin's inhibition of platelet function 63,64 and its utility in protecting vascular anastomoses.39,65

Dextran is used in microsurgery as an antiplatelet agent,34 although this action of the drug is disputed.35 Its effects may include volume expansion, 34 decreased blood viscosity,7 an enhanced fibrinolysis.35 Dextran's presumed utility in microsurgery is based on numerous experimental and clinical reports indicating that its use helps ensure patency following vessel repair.7,66-68 Low molecular weight dextran-40 is the most commonly used dextran in microsurgery.

Although used routinely by some groups early in the development of microsurgical techniques,69 systemic heparin is now used primarily as an anticoagulant adjunct in the management of traumatized replanted tissue1,33,40 and anastomotic revisions. 31,36 Heparin is also used as a vessel irrigant before anastomosis36 and topically to promote bleeding from the nail beds of replanted digits with known or suspected venous impairment.1,20,70

Fibrinolytics are used routinely in replantation surgery reported by Tamai,37,71 but otherwise are used as adjuncts to salvage procedures.4 Experimental studies report that human plasiminogen activator can promote patency in a microvascular thrombosis model. 50, 72.

next page...