Expanding indications for the use of thrombolytic agents in acute myocardial infarction.

A large body of data from randomized clinical trials have definitely established that thrombolytic therapy in acute myocardial infarction reduces the risk of early mortality by approximately one fourth. Unfortunately, most (but not all) trials have been unduly restrictive in selecting patients who have been entered. Consequently, at least half of the patients (many of whom are at high risk of death) who present with signs and symptoms of acute myocardial infarction are not considered for such therapy. A critical analysis of the data from all the available trials indicates that thrombolytic therapy reduces mortality in a much broader group of patients than generally believed. For example, patients who present late (i.e., 6-24 h) after the onset of symptoms, those over the age of 75 years, those with classical symptoms but minor or no abnormalities on the first electrocardiogram, those with low or high blood pressure, and patients in several other subgroups have been shown to benefit. The absolute and relative risk of major adverse effects (such as major bleeding episodes or strokes) have been so low that in each of these subgroups the benefits of treatment far outweigh their potential risks.