Prospective evaluation comparing the effects of enalapril and losartan in left ventricular remodeling after acute myocardial infarction

Background Previous studies have compared angiotensin receptor blockers and angiotensin-converting enzyme inhibitors in patients with heart failure, but there are few data about the effect of these drugs regarding left ventricular remodeling after myocardial infarction. Methods Fifty-two consecutive patients with first anterior wall myocardial infarction within 24 hours of evolution were randomized to receive enalapril (as much as 20 mg; mean, 14.6 mg), or losartan (as much as 50 mg; mean, 48 mg). Left ventricular ejection fraction and ventricular volumes were analyzed in 2 serial radionuclide ventriculograpies, carried out within 4 days after the infarction (mean, 97.4 ± 114.2 hours) and after 6 months (mean, 177.7 ± 16.7 days). Ventriculographies were analyzed by a single blinded observer. Mainly because of the unexpected large SD values obtained, the power of the study to demonstrate equivalence between the groups was only 15.7%. Results The differences obtained between the first and the second ventriculographies, for the enalapril and losartan groups, were: for left ventricular ejection fraction, −0.4% ± 6.6% versus −1.1% ± 5.9% (P = . 67; 95% CI, 2.77-4.23); for final systolic volume, 0.07 ± 7.7 mL/m2 versus −0.2 ± 6.1mL/m2 (P = . 85; 95% CI, −3.57-4.26); for final diastolic volume −0.7 ± 12.1 mL/m2 versus −3.6 - 9.9 mL/m2 (P = . 34; 95% CI, −3.22-9.17). Conclusion This study, although underpowered, suggests that neither enalapril nor losartan was superior as compared with each other for left ventricular remodeling after myocardial infarction; however, powerful evidence of equivalence was not provided.