Beta-blockers may not help after acute heart attack if ejection fraction preserved
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Key takeaways:
- Beta-blocker use did not reduce risk for death or new MI in patients with acute MI and preserved ejection fraction.
- The results conflict with guidance recommending beta-blockers for all patients with MI.
ATLANTA — In patients who underwent early angiography for acute MI and had ejection fraction of 50% or more, long-term beta-blocker use did not reduce risk for death or new MI compared with no use, researchers reported.
For the open-label REDUCE-AMI trial, presented at the American College of Cardiology Scientific Session and simultaneously published in The New England Journal of Medicine, Troels Yndigegn, MD, an interventional cardiologist currently serving as the chief of the department of cardiology at Skåne University Hospital, Lund, Sweden, and colleagues randomly assigned 5,020 patients with acute MI who underwent early angiography and had EF of at least 50% to a beta-blocker (metoprolol or bisoprolol) or no beta-blocker treatment.
“Current guidelines widely recommend the routine use beta-blockers after myocardial infarction,” Yndigegn said during a presentation. “However, prior studies involved patients with large myocardial infarctions, often with left ventricular systolic dysfunction, and this was in an era predating reperfusion treatment and secondary prevention. A meta-analysis conducted of trials from the reperfusion eras did not show an effect on mortality in patients with myocardial infarction.. ... Recently, Cochrane Review has addressed a need for clinical trials on beta-blocker therapy in current clinical practice. There is a need for adequately powered clinical trials of beta-blocker therapy in acute MI patients with preserved ejection fraction. We therefore designed the REDUCE-AMI trial with the aim to determine whether long-term oral beta-blocker treatment in patients with acute MI and preserved ejection fraction improves the outcome of death or new MI.”
All patients (median age, 65 years; 22% women) underwent randomization 1 to 7 days after their type 1 MI (STEMI or non-STEMI), had coronary angiography performed during their hospitalization, had obstructive coronary disease diagnosed before randomization and had echocardiography confirming EF of at least 50% after the MI, he said. Median follow-up was 3.5 years.
No effect from beta-blockers
The primary endpoint of death or new MI occurred in 7.9% of the beta-blocker group and 8.3% of the control group (HR = 0.96; 95% CI, 0.79-1.16; P = .64), Yndigegn said during the presentation.
The researchers also found no difference between the groups in the following outcomes:
- all-cause death (HR = 0.94; 95% CI, 0.71-1.24);
- new MI (HR = 0.96; 95% CI, 0.74-1.24);
- CV death (HR = 1.15; 95% CI, 0.72-1.84);
- hospitalization for atrial fibrillation (HR = 0.79; 95% CI, 0.48-1.31);
- hospitalization for HF (HR = 0.91; 95% CI, 0.5-1.66);
- hospitalization for bradycardia, second- or third-degree atrioventricular block, hypotension, syncope or implantation of a pacemaker (HR = 1.08; 95% CI, 0.79-1.46);
- hospitalization for chronic obstructive pulmonary disease or asthma (HR = 0.94; 95% CI, 0.46-1.89); and
- hospitalization for stroke (difference in the restricted mean survival time in days within the largest follow-up time = 6.8 days; 95% CI, –7.11 to 20.72; HR = 0.78; 95% CI, 0.51-1.21).
There were also no differences between the groups in dyspnea or angina at 6 to 10 weeks and at 11 to 13 months, Yndigegn said.
“In light of these findings, REDUCE-AMI challenges the routine prescription of beta-blockers in acute MI patients with preserved ejection fraction,” Yndigegn said at a press conference. “They provide an opportunity to tailor treatments to individual patient profiles.”
Making beta-blockers less routine
In a related editorial published in NEJM, P. Gabriel Steg, MD, chief of the cardiology department at Hôpital Bichat, Paris, and professor of cardiology at the Université de Paris, wrote: “Given the difficulty of unambiguously showing an absence of benefit with beta-blocker therapy and the limitations of a single, somewhat underpowered, open-label trial, it may be too early to cut beta-blockers from the ‘secondary prevention team’ definitively. While we await the results of the multiple upcoming trials reevaluating the role of beta-blockers in contemporary care, it may be prudent to place routine beta-blocker therapy after myocardial infarction on ‘injured reserve.’”
References:
- Steg PG. N Engl J Med. 2024;doi:10.1056/NEJMe2402731.
- Yndigegn T, et al. N Engl J Med. 2024;doi:10.1056/NEJMoa2401479.
Perspective
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The investigators should be congratulated for being willing to question old dogma. The post-MI setting is a vulnerable period. Conventional dogma that came from studies from 1981 and 1982 stated ‘let’s let the heart rest.’ But that was before thrombolytics, antiplatelet drugs, PCI or any of the guideline-directed medical therapy we have now. Perhaps that notion does not necessarily hold water when you have already revascularized patients.
These findings may serve as an interesting extension from the HF world, where we know guideline-directed medical therapy apply without question to reduced EF, but in HF with preserved EF, we actually tend to avoid beta-blocker unless for a specific indication. As a heart failure doctor, these data do not necessarily surprise me; however, we have to recognize the study’s limitations.
I think these findings will take some time to translate into clinical practice and require further evidence before doing so. The cohort came predominantly from Sweden and were men. So I would hesitate before saying I will not use beta-blockers post-MI in patients with preserved EF. We have to recognize that this is a selected population that had no other indication for beta-blockers such as atrial fibrillation or ventricular ectopy. They were all revascularized.
That being said, what the study may offer is a feeling of relative safety in not putting similar patients on beta-blockers, especially in those who may be negatively impacted by a beta-blocker by virtue of having any degree of heart block or hypotension or reactive airway disease. With time and if similar results are demonstrated across a broader patient population, we may indeed change our practice.
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Yndigegn T, et al. Joint American College of Cardiology/New England Journal of Medicine Late-breaking clinical trials III. Presented at: American College of Cardiology Scientific Session; April 6-8, 2024; Atlanta.
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