Impact of beta-blockers on cardiovascular outcomes in myocardial infarction patients with preserved or mildly reduced ejection fraction: Systematic review and meta-analysis of randomized trials.
Abstract
Objective
To evaluate the association between beta-blocker therapy and major cardiovascular outcomes in patients with acute myocardial infarction (AMI) and preserved or mildly reduced left ventricular ejection fraction (LVEF).
Design
Systematic review and meta-analysis of randomized clinical trials.
Setting
A comprehensive search of five electronic databases was conducted using a predefined PICO strategy to identify published studies. Seven studies were selected and included in the meta-analysis.
Participants
Patients with AMI and preserved or mildly reduced LVEF who received beta-blocker therapy.
Intervention
Use of beta-blockers. MAIN OUTCOME MEASURES Primary composite outcome including mortality, reinfarction, cardiovascular-related hospitalization, and other cardiovascular events.
Results
This meta-analysis included four studies comprising a total of 18,504 patients with a history of AMI and an LVEF ≥ 40%. Among them, 2223 patients had mildly reduced LVEF, while 15,908 belonged to the preserved LVEF group. Beta-blocker therapy did not reduce the primary composite outcome (death, reinfarction, and hospitalization) in patients with LVEF ≥ 40% (hazard ratio [HR]: 0.90; 95% confidence interval [95% CI]: 0.81-1.01). Subsequent subgroup analyses showed that beta-blocker therapy did not reduce the primary composite outcome in patients with preserved LVEF (HR: 0.94; 95% CI: 0.87-1.03); however, in patients with mildly reduced LVEF, it was associated with a reduction in the same primary composite outcome (HR: 0.82; 95% CI: 0.70-0.97).
Conclusions
In this meta-analysis, beta-blocker use was not associated with a significant reduction in the primary composite outcome or in mortality or reinfarction. The association observed in patients with mildly reduced ejection fraction derives from a subgroup and should be interpreted with caution in the context of an overall neutral result.