Antiplatelet and anticoagulant therapy during coronary thrombolysis.

Plasminogen activators reduce mortality in patients with acute myocardial infarction primarily by inducing reperfusion at a time when the myocardium is still viable. Consequently, important determinants of the clinical response to thrombolytic therapy include the patency rate, the timing of reperfusion, and the frequency of coronary reocclusion. With present thrombolytic agents, coronary patency is not achieved in 30%-50% of patients and reperfusion is often delayed for more than 60 min after initiating thrombolytic therapy. Even in those that achieve patency, reperfusion flow, an important determinant of myocardial salvage, may be limited by incomplete clot lysis and residual coronary stenosis. Finally, reocclusion has been reported in 15%-25% of patients and has serious clinical consequences. Experimental and clinical evidence suggests that many of these problems reflect ongoing platelet activation and thrombosis. Thus, there is a rational basis to assume that the clinical benefit of thrombolytic therapy will be enhanced by the addition of antiplatelet and anticoagulant agents.