Bleeding during thrombolytic therapy for acute myocardial infarction: mechanisms and management.

Hemorrhage is the major adverse effect of thrombolytic therapy, but its incidence can be reduced by careful selection of patients and avoidance of unnecessary invasive procedures. More than 70% of bleeding episodes occur at vascular puncture sites. Hypofibrinogenemia and elevation of fibrinogen degradation products have been weakly correlated with the risk of hemorrhage. Although depletion of factors V and VIII may occur, the role of such depletion in bleeding is unknown. Several in-vitro studies have shown plasmin-induced platelet dysfunction, but clinical data are limited. Nevertheless, the role of platelet inhibition should be considered because many patients are treated with antiplatelet agents. Most patients who have bleeding can be managed by interruption of thrombolytic and anticoagulant therapy, volume replacement, and manual pressure applied to an incompetent vessel. Protamine should be considered if heparin has been administered within 4 hours of the onset of bleeding. In the few patients who fail to respond to these conservative measures, judicious use of transfusion products may be indicated. Transfusion of cryoprecipitate, fresh frozen plasma, and platelets should be considered with clinical and laboratory reassessment after each administration. A target fibrinogen level of 1 g/L is desirable with cryoprecipitate infusion. Antifibrinolytic agents are available as a last alternative. We have developed an algorithm for using these products.