Anticoagulation with prostaglandins during extracorporeal circulation

This paper reviews pathophysiological processes occurring after contact of blood with artificial surfaces and the predominant role of platelets in the genesis of extracorporeal thrombosis. Bleeding complications are common du ring conventional heparin anticoagulation, and both clinical and experiment al evidence suggests that the efficacy of heparin as an anticoagulant is co mpromised by its relative ineffectiveness towards platelets. Consequently, drugs that inhibit interaction between platelets and artificial membranes h ave been introduced as an alternative anticoagulant strategy. This paper re views studies on the use of short-acting antiplatelet prostaglandins such a s prostacyclin and prostaglandin E-1 alone or in combination with heparin d uring various forms of extracorporeal circulation such as cardiopulmonary b ypass, haemodialysis, continuous haemofiltration, membrane oxygenation, ven tricular assist devices, and haemoperfusion. Temporary paralysis of platele t function with antiplatelet prostaglandins has been effective in controlli ng platelet-surface interaction and reducing bleeding complications and mor bidity during and after extracorporeal circulation. By inhibiting the forma tion of fibrin, leukocyte and platelet-based microaggregates and cytoprotec tive actions, prostaglandins have been shown to prevent renal, neurologic, and pulmonary dysfunction after extracorporeal circulation. Prostaglandins were most effective in increasing the biocompatibility of extracorporeal sy stems when they were administered as a supplement to but not as a substitut e for heparin. The use of prostaglandins alone should be reserved for patie nts who are resistant to heparin or heparin-induced thrombocytopenia.