What does this research mean for the field?

Beta-blocker therapy at discharge reduces 1-year major adverse cardiac events by 37% in patients with left ventricular ejection fraction (LVEF) ≤40% and by 31% in patients with 40% < LVEF < 50% after acute myocardial infarction. Novelty: ClaimNovelty.CONFIRMATORY. Consensus alignment: ConsensusAlignment.SUPPORTS_CONSENSUS.

April 8, 2020

Effect of beta-blocker therapy in patients with or without left ventricular systolic dysfunction after acute myocardial infarction

Q: What are the key findings of this study?

Beta-blocker therapy at discharge reduced 1-year major adverse cardiac events by 37% in patients with LVEF ≤40% (HR 0.63) and 31% with 40% < LVEF < 50% (HR 0.69).

Key Result

Beta-blocker therapy at discharge reduced 1-year major adverse cardiac events by 37% in patients with LVEF ≤40% (HR 0.63) and 31% with 40% < LVEF < 50% (HR 0.69).

Structured PICO

Does beta-blocker therapy at discharge reduce 1-year major adverse cardiac events in patients surviving acute myocardial infarction across different LVEF categories?

Population

12,200 in-hospital survivors of acute myocardial infarction (AMI) enrolled in the Korea Acute Myocardial Infarction Registry-National Institute of Health (KAMIR-NIH)

Intervention

Beta-blocker therapy at discharge

Comparator

No beta-blocker therapy at discharge

Outcome

1-year major adverse cardiac events (MACE), defined as a composite of cardiac death, myocardial infarction, revascularization, and readmission due to heart failurecomposite

Beta-blocker therapy at discharge after acute myocardial infarction is associated with improved 1-year clinical outcomes in patients with reduced or mid-range LVEF, but provides no significant benefit in those with preserved LVEF.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Abstract Aims This observational study aimed to investigate the association between beta-blocker therapy and clinical outcomes in patients with acute myocardial infarction (AMI), especially with mid-range or preserved left ventricular systolic function. Methods and results Among 13 624 patients enrolled in the Korea Acute Myocardial Infarction Registry-National Institute of Health (KAMIR-NIH), 12 200 in-hospital survivors were selected. Patients with beta-blockers showed significantly lower 1-year major adverse cardiac events (MACE), which was a composite of cardiac death, MI, revascularization, and readmission due to heart failure [9.7 vs. 14.3/100 patient-year; hazard ratio (HR) 0.84, 95% confidence interval (CI) 0.72–0.97; P = 0.022). However, this association had a significant interaction with left ventricular ejection fraction (LVEF). Beta-blocker therapy at discharge was associated with lower 1-year MACE in patients with LVEF ≤40% (HR 0.63, 95% CI 0.48–0.81; P 0.001), and 40% LVEF 50% (HR 0.69, 95% CI 0.51–0.94; P = 0.020), but not in patients with LVEF ≥50% (HR 1.16, 95% CI 0.91–1.48; P = 0.234). Conclusions Beta-blocker therapy at discharge was associated with better 1-year clinical outcomes in patients with reduced or mid-range LVEF after AMI, but not in patients with preserved LVEF. These data suggested that the long-term beta-blocker therapy may be guided by LVEF.

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