Beta-blocker use after MI and preserved ejection fraction offers no benefit: REDUCE-AMI trial

The study revealed that long-term beta-blocker treatment did not result in a lower risk of the composite primary end point of death from any cause or new MI than no beta-blocker use among patients with acute MI who underwent early coronary angiography and had a preserved left ventricular EF (≥50%).

"By a median follow-up of 3.5 years, the primary composite endpoint — all-cause death or recurrent acute MI — did not differ significantly between participants randomized to a beta-blocker versus no beta-blocker (7.9% vs. 8.3%, respectively)," the researchers reported.

The two groups also did not differ significantly in secondary endpoints (cardiovascular death, all-cause death, new MI, heart failure, or hospitalization for atrial fibrillation) or safety outcomes.

Most trials that have shown that beta-blocker treatment is beneficial after myocardial infarction included patients with large myocardial infarctions and were conducted in an era before the modern biomarker-based diagnosis of MI, and treatment with percutaneous coronary intervention, high-intensity statins, antithrombotic agents, and renin-angiotensin-aldosterone system antagonists. Troels Yndigegn, Department of Clinical Sciences, Lund University, Skane University Hospital, Lund, Sweden, and colleagues conducted a parallel-group, open-label trial performed at 45 centers in Sweden, New Zealand, and Estonia to update the evidence.

The study included patients with an acute myocardial infarction who had undergone coronary angiography and had a left ventricular ejection fraction of at least 50%. They were randomly assigned to receive either long-term treatment with a beta-blocker (metoprolol or bisoprolol) or no beta-blocker treatment. The primary endpoint was a composite of death from any cause or new myocardial infarction.

5020 patients were enrolled (95.4% of whom were from Sweden) were enrolled from 2017 to 2023. The median follow-up was 3.5 years. Based on the study, the researchers reported the following findings:

• A primary end-point event occurred in 7.9% of patients in the beta-blocker group and 8.3% of patients in the no–beta-blocker group (hazard ratio, 0.96).
• Beta-blocker treatment did not appear to lead to a lower cumulative incidence of the secondary endpoints (death from any cause, 3.9% in the beta-blocker group and 4.1% in the no–beta-blocker group; death from cardiovascular causes, 1.5% and 1.3%, respectively; hospitalization for atrial fibrillation, 1.1% and 1.4%; myocardial infarction, 4.5%, and 4.7%; and hospitalization for heart failure, 0.8%, and 0.9%).
• Concerning safety endpoints, hospitalization for bradycardia, second- or third-degree atrioventricular block, hypotension, syncope, or implantation of a pacemaker occurred in 3.4% of the patients in the beta-blocker group, and 3.2% of those in the no–beta-blocker group; hospitalization for asthma or chronic obstructive pulmonary disease in 0.6% and 0.6%, respectively; and hospitalization for stroke in 1.4% and 1.8%.

The findings suggest that beta-blocker therapy does not provide benefits in a relatively low-risk population with AMI who have a normal LVEF after revascularization and who receive other evidence-based therapies.

The trial's limitations were open-label design and relatively frequent crossover.

Reference:

Yndigegn T, Lindahl B, Mars K, Alfredsson J, Benatar J, Brandin L, Erlinge D, Hallen O, Held C, Hjalmarsson P, Johansson P, Karlström P, Kellerth T, Marandi T, Ravn-Fischer A, Sundström J, Östlund O, Hofmann R, Jernberg T; REDUCE-AMI Investigators. Beta-Blockers after Myocardial Infarction and Preserved Ejection Fraction. N Engl J Med. 2024 Apr 7. doi: 10.1056/NEJMoa2401479. Epub ahead of print. PMID: 38587241.