Hierarchy of risk based on history and location of prior myocardial infarction in the thrombolytic era

Background Among patients receiving thrombolytic therapy for myocardial infarction, the outcome for those with a history of infarction is dramatically worse than for those with their first event. Methods and Results We performed a post hoc analysis of patients with a history of myocardial infarction enrolled in the Global Utilization of Streptokinase and TPA for Occluded arteries (GUSTO)-I trial, focusing on the impact of the location of their current and prior events on mortality rates. Within the first 24 hours, mortality rate was greatest among patients with a current infarction in a territory remote from their previous event. By 48 hours after examination, mortality rates among patients with a second anterior infarct had overtaken that among patients with a current inferior/prior anterior infarct. This hierarchy of risk persisted at both 30 days and 1 year (mortality rate at 1 year: current anterior/prior inferior 23.2% ± 1.4%, current anterior/prior anterior 20% ± 1.5%, current inferior/prior anterior 17% ± 1.2%, current inferior/prior inferior 10.8% ± 0.9%). Conclusions In patients with ST-elevation myocardial infarction on a background of prior infarction, the location of current and prior events predicts a hierarchy of short- and long-term risk of death. (Am Heart J 2000;140:29-33.)