Effect of very early angiotensin-converting enzyme inhibition on left ventricular dilation after myocardial infarction in patients receiving thrombolysis - Results of a meta-analysis of 845 patients

OBJECTIVES: We sought to investigate the effect of angiotensin-converting e nzyme (ACE) inhibition <9 h after myocardial infarction (MI) on left ventri cular (LV) dilation in patients receiving thrombolysis. BACKGROUND: The ACE inhibitors reduce mortality after MI. Attenuation of LV dilation has been suggested as an important mechanism. METHODS: The data of 845 patients with three-month echocardiographic follow -up after MI were combined from three randomized, double-blind, placebo-con trolled studies. The criteria for these studies included: 1) thrombolytic t herapy; 2) ACE inhibition within 6 to 9 h; and 3) evaluation of LV dilation as the primary objective. RESULTS: The ACE inhibitor was started 3.2 +/- 1.7 h after the patients' fi rst (mainly, 85%) anterior MI. After three months, LV dilation was not sign ificantly attenuated by very early treatment with an ACE inhibitor. The dia stolic volume index was attenuated by 0.5 ml/m(2) (95% confidence interval [CI] -1.5 to 2.5, p = 0.61), and the systolic volume index by 0.5 ml/m2 (95 % CI -1.0 to 1.9, p = 0.50). Subgroup analysis demonstrated that LV dilatio n was significantly attenuated by ACE inhibitor treatment for patients in w hom reperfusion failed. In contrast, LV dilation was almost unaffected by A CE inhibitor treatment in successfully reperfused patients. CONCLUSIONS: We could not demonstrate attenuation of LV dilation in patient s receiving thrombolysis by ACE inhibitor treatment within 6 to 9 h after M I. We speculate that very early treatment with an ACE inhibitor has a benef icial effect on LV remodeling only in patients in whom reperfusion failed. Other mechanisms may be responsible for the beneficial effects of ACE inhib itors in successfully reperfused patients after MI. (C) 2000 by the America n College of Cardiology.