Are we inhibited? Renal insufficiency should not preclude the use of ACE inhibitors for patients with myocardial infarction and depressed left ventricular function

Context: Angiotensin-converting enzyme (ACE) inhibitors have been shown to decrease mortality in patients with myocardial infarction and depressed left ventricular function, but physicians may be reluctant to prescribe ACE inhibitors to patients with concomitant renal insufficiency. Objective: To evaluate whether patients with depressed left, ventricular ejection fraction following acute myocardial infarction have a similar reduction in mortality from ACE inhibitors regardless of their renal function. Design: Retrospective cohort study using medical record data. Setting: All nonfederal acute care hospitals. Patients: A cohort of 20902 Medicare beneficiaries aged 65 years and older directly admitted to the hospital from February 1, 1994, through July 30, 1995, and with a documented left ventricular ejection fraction of less than 40% measured by echocardiography, radionuclide scintigraphy, or angiography following a confirmed acute myocardial infarction. Main Outcome Measures: One-year survival for patients who received or who did not receive an ACE inhibitor at hospital discharge, stratified by the patient's level of renal function. Results: For the entire cohort, the receipt of an ACE inhibitor on hospital discharge was associated with greater 1-year survival (hazards ratio, 0.84; 95% confidence interval, 0.77-0.91) after adjusting for patient demographic characteristics, comorbidity, severity of illness (including left ventricular ejection fraction), and the receipt of other therapies. In stratified models, the receipt of an ACE inhibitor was associated with a 37% (16%-52%) lower mortality for patients who had poor renal function (serum creatinine level,<265 mu mol/L [<3 mg/dL]) and a 16% (8%-23%) lower mortality for patients who had better renal function. Use of aspirin therapy attenuated the benefit of ACE inhibitors in patients with poor renal function. Conclusions: Moderate renal insufficiency should not be considered a contraindication to the use of ACE inhibitors in patients with depressed left ventricular ejection fraction following myocardial infarction. Use of aspirin therapy may attenuate the benefit of ACE inhibitors in patients with high serum creatinine levels; therefore, further studies are needed to determine whether treatment with aspirin, alternative antiplatelet agents, or anticoagulation is indicated for these patients.