Reperfusion therapy of acute myocardial infarction

Abstract

I N 1979, DUCKERT reviewed the completed trials of intravenous (IV) thrombolytic therapy in acute myocardial infarction (MI) for this journal.’ Duckert stated in his review, “It is fair to conclude that today the value of thrombolytic treatment of acute MI has not been established.” Since this review, dramatic advances have been made in the understanding of pathogenesis of MI, knowledge of thrombolysis, advances in technology, and stratification of risk groups. With these advances in understanding and the completion of several large, prospective randomization clinical trials, a much clearer picture of the clinical use of reperfusion therapy of MI has evolved. In 1979, only prolonged IV infusion of thrombolytic agents had been studied; since then, numerous other reperfusion strategies, including coronary bypass, intracoronary streptokinase infusion, short-term high-dose IV infusion of thrombolytic agents, and coronary angioplasty (PTCA), have been used. For these reasons, a review of the current status of reperfusion therapy is timely. The rationale and experimental basis for using reperfusion therapy has been extensively reviewed elsewhere.2-‘4 In an analysis of the clinical benefit of reperfusion therapy, three fundamental questions must be addressed. First, how does therapy alter the pathogenesis of acute MI? Second, does therapy salvage myocardium or, indirectly, does therapy preserve ventricular function? Finally, and most importantly, does therapy alter mortality? This review will examine these fundamental questions for each of the currently used reperfusion strategies. Before these questions can be addressed, an understanding of the natural history of thrombotic coronary occlusion, changes in ventricular function, and mortality must be examined. NATURAL HISTORY OF CORONARY