Use and Effectiveness of Intravenous Heparin Therapy for Treatment of Acute Myocardial Infarction in the Elderly

OBJECTIVES: We sought to determine the use and association with 30-day mortality of intravenous heparin for the treatment of acute myocardial infarction in elderly patients not treated with a reperfusion strategy and without contraindications to anticoagulation. BACKGROUND: The benefit of using full-dose intravenous heparin for the treatment of acute myocardial infarction in the elderly is not known. METHODS: We conducted a retrospective cohort study using hospital medical records of all Medicare beneficiaries admitted to the hospital with an acute myocardial infarction in Alabama, Connecticut, Iowa and Wisconsin from June 1992 through February 1993. RESULTS: Among the 6,935 patients > or = 65 years old who had no absolute chart-documented contraindications to heparin, 3,227 (47%) received early full-dose intravenous heparin therapy. After adjustment for baseline differences in demographic, clinical and treatment factors between patients with and without heparin, the use of heparin (odds ratio 1.02, 95% confidence interval 0.87 to 1.18) was not associated with a significantly better 30-day mortality rate. CONCLUSIONS: Although intravenous heparin was commonly used for treatment of acute myocardial infarction in the elderly, it was not associated with an improved 30-day mortality rate. Although the findings of this observational study must be interpreted with care, they lead us to question whether the prevalent use of intravenous heparin has therapeutic effectiveness in this population.