Effect of age on use of thrombolytic therapy and mortality in acute myocardial infarction

Abstract

The findings in 3,256 consecutive patients hospitalized for acute myocardial infarction were tabulated to assess the history, treatments and outcome in the elderly; 1,848 patients (56%) were >65 years of age, including 28% who were aged ≥75 years. The incidence of prior angina, hypertension and heart failure (only 3% of patients <55 years of age had a history of heart failure compared with 24% ≥75 years old) was found to increase with age. Twenty-nine percent of patients <75 years of age were treated with a systemic thrombolytic drug compared with only 5% of patients older than 75 years.Mortality rates increased strikingly with advanced age (< 2% in patients ≤55, 4.6% in those 55 to 64, 12.3% in those 65 to 74 and 17.8% in those ≥75 years). Both the incidence of complicating illness and a nondiagnostic electrocardiogram (ECG) increased with age. In a multivariate analysis of outcome in older patients (≥ 65 years), adverse events were related to both prior history of heart failure (odds ratio 3.9) and increasing age (odds ratio 1.4 per each decade of age). Outcome was not improved by treatment with thrombolytic drugs, but these agents were prescribed to only 12% of patients >65 years of age, thereby reducing the power for detecting such an effect.These findings show that the elderly frequently develop acute infarction in the setting of prior complications from ischemic heart disease and have an extremely high hospital mortality rate: the decision to treat these patients is hampered by their higher incidence of complicating illness, absence of chest pain on admission and nonspecific ECG abnormalities.