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

Abstract

OBJECTIVESWe sought to investigate the effect of angiotensin-converting enzyme (ACE) inhibition <9 h after myocardial infarction (MI) on left ventricular (LV) dilation in patients receiving thrombolysis.BACKGROUNDThe ACE inhibitors reduce mortality after MI. Attenuation of LV dilation has been suggested as an important mechanism.METHODSThe data of 845 patients with three-month echocardiographic follow-up after MI were combined from three randomized, double-blind, placebo-controlled studies. The criteria for these studies included: 1) thrombolytic therapy; 2) ACE inhibition within 6 to 9 h; and 3) evaluation of LV dilation as the primary objective.RESULTSThe ACE inhibitor was started 3.2 ± 1.7 h after the patients’ first (mainly, 85%) anterior MI. After three months, LV dilation was not significantly attenuated by very early treatment with an ACE inhibitor. The diastolic volume index was attenuated by 0.5 ml/m2 (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 dilation was significantly attenuated by ACE inhibitor treatment for patients in whom reperfusion failed. In contrast, LV dilation was almost unaffected by ACE inhibitor treatment in successfully reperfused patients.CONCLUSIONSWe could not demonstrate attenuation of LV dilation in patients receiving thrombolysis by ACE inhibitor treatment within 6 to 9 h after MI. We speculate that very early treatment with an ACE inhibitor has a beneficial effect on LV remodeling only in patients in whom reperfusion failed. Other mechanisms may be responsible for the beneficial effects of ACE inhibitors in successfully reperfused patients after MI.