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Beta-Blockers After Myocardial Infarction With Preserved and Mildly Reduced Ejection Fraction: A Meta-Analysis With
Michele Maremmani1, Paolo Gianfico2, Christian Templin3,4
1Department of Cardiology, Sant'Andrea Hospital, La Spezia, Italy.
Insights
Beta-blockers show no benefit for myocardial infarction (MI) patients with preserved ejection fraction, with conclusive evidence of futility. However, they reduced major adverse cardiovascular events in those with mildly reduced ejection fraction, requiring further study.
Area of Science:
- Cardiology
- Pharmacology
- Clinical Trials
Background:
- Beta-blockers are standard therapy post-myocardial infarction (MI).
- Their efficacy may vary based on left ventricular ejection fraction (LVEF).
- Evidence on beta-blocker use across LVEF strata needs further evaluation.
Purpose of the Study:
- To assess beta-blocker efficacy in post-MI patients stratified by LVEF.
- To evaluate the conclusiveness of existing evidence using Trial Sequential Analysis (TSA).
Main Methods:
- Systematic search of PubMed, Embase, and ClinicalTrials.gov for relevant RCTs.
- Time-to-event meta-analysis and Mantel-Haenszel method for risk ratios (RR).
- LVEF-stratified analyses and TSA to determine statistical significance and futility.
Main Results:
- Beta-blockers did not reduce the primary endpoint or mortality in post-MI patients (HR 0.92, 95% CI 0.85-1.01).
- No significant reduction in death or MACE observed in patients with preserved LVEF (≥50%), with TSA confirming futility.
- A significant reduction in MACE was noted in patients with mildly reduced LVEF (40%-49%) (RR 0.74, 95% CI 0.58-0.94), though TSA did not confirm conclusiveness.
Conclusions:
- Beta-blockers offer no benefit in post-MI patients with preserved LVEF, with conclusive evidence of futility.
- Therapy showed a potential benefit in reducing MACE for patients with mildly reduced LVEF.
- Further adequately powered randomized trials are needed to confirm findings in the mildly reduced LVEF group.
Aims:
We aimed to evaluate the efficacy of β-blockers after myocardial infarction (MI) across left ventricular ejection fraction (LVEF) strata and to assess the conclusiveness of the available evidence using trial sequential analysis (TSA).
Methods:
PubMed, Embase and ClinicalTrials.gov were searched for randomized controlled trials (RCTs) evaluating β-blockers in post-MI patients with LVEF ≥ 40%. A time-to-event meta-analysis was performed for the primary composite (as defined by each trial) and for individual endpoints. The Mantel-Haenszel method was used to pool risk ratios (RR) for major adverse cardiovascular events (MACE; death, MI or heart failure), including LVEF-stratified analyses. TSA estimated the required information size (RIS) and generated adjusted significance and futility boundaries, assuming a 5% type I error and 90% power.
Results:
Across 19,826 post-MI patients (17,941 with LVEF ≥ 50% and 1885 with LVEF 40%-49%), β-blockers did not reduce time to the primary endpoint (HR 0.92, 95% CI 0.85-1.01; p = 0.08; I2 = 35%) or mortality. In patients with preserved LVEF (≥ 50%), β-blocker therapy did not reduce the risk of death or MACE (RR 0.96, 95% CI 0.87-1.05; I2 = 42%), with TSA confirming futility. Among those with mildly reduced LVEF (40%-49%), β-blockers reduced MACE (RR 0.74, 95% CI 0.58-0.94; I2 = 0%), although TSA failed to establish conclusiveness (RIS of 5717 [14.4%]). A significant interaction by LVEF subgroup was observed for cardiac death (p = 0.03).
Conclusions:
β-blockers conferred no benefit in post-MI patients with preserved LVEF, with conclusive evidence of futility, whereas therapy was associated with reduced MACE in those with mildly reduced LVEF, pending confirmation in further adequately powered randomized trials.
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