Beta-blockers post-MI no longer needed
Key Takeaways
The REDUCE-AMI trial found that long-term beta-blocker treatment did not lead to a lower risk of death or recurrent MI compared to no beta-blocker use in patients with acute MI and preserved ejection fraction (≥50%).
Advances in modern diagnosis and treatment of MI and coronary artery disease may have diminished the benefits of beta-blocker therapy post-MI in patients with preserved ejection fraction.
The use of beta-blockers in patients with reduced ejection fraction or other cardiomyopathies has not been challenged by this study.
For at least a quarter of a century, the initiation of beta-blockers for secondary prevention of cardiovascular disease (CVD) in patients after myocardial infarction (MI) or acute coronary syndrome (ACS) has been the unquestioned standard of care.
Until now.
At the American College of Cardiology meeting this April 2024, surprising results were presented from a large trial of beta-blockers after MI with preserved ejection fraction, calling into question the long-held practice of prescribing beta-blockers post-MI.
Surprising findings
The REDUCE-AMI trial was a parallel-group, open-label trial of 5,020 patients, performed at centers in New Zealand, Sweden, and Estonia.[] Patients with acute MI who had undergone coronary angiography and maintained a left ventricular ejection fraction (LVEF) of at least 50% were randomized to receive either long-term treatment with metoprolol or bisoprolol, or no beta-blocker treatment.
The primary endpoint was a composite of all-cause death or recurrent MI over a median follow-up of 3.5 years.
Treatment with beta-blockers did not lead to a lower risk of the composite primary endpoint, nor did it lead to a lower cumulative incidence of the secondary endpoints.
Death from any cause occurred in 3.9% of patients receiving beta-blockers and 4.1% of patients in the no-beta-blocker group; respective results for other endpoints were death from cardiovascular causes, 1.5% and 1.3%; hospitalization for heart failure, 0.8% and 0.9%; myocardial infarction, 4.5% and 4.7%; and hospitalization for atrial fibrillation, 1.1% and 1.4%.
Hospitalization for safety endpoints of bradycardia, atrioventricular block, syncope, hypotension, or pacemaker implantation occurred in 3.4% of patients in the beta-blocker group and in 3.2% of those in the no-beta-blocker group.
From these findings, the study authors concluded: “Among patients with acute myocardial infarction who underwent early coronary angiography and had a preserved [LVEF] (≥50%), long-term beta-blocker treatment did not lead to a lower risk of the composite primary end point of death from any cause or new myocardial infarction than no beta-blocker use.”
Why the change?
As the researchers note, the majority of clinical trials that have shown benefit from beta-blocker treatment post-MI included patients with large infarct territories and were conducted years ago—that is, in an era “before modern biomarker-based diagnosis of myocardial infarction and treatment with percutaneous coronary intervention, antithrombotic agents, high-intensity statins, and renin-angiotensin-aldosterone system antagonists.”
Simply put, as treatment of coronary artery disease (CAD) and ACS has advanced over the past two decades, the benefits of beta-blocker therapy have been eclipsed by new and more effective standards of care. It may no longer be necessary to expose patients to the well-known side effects of beta-blockers, including fatigue, weight gain, and sexual dysfunction.
It is also important to note that this study was limited to patients with preserved ejection fraction, and the use of beta-blockers such as carvedilol in patients with reduced ejection fraction or other cardiomyopathies has not yet been challenged.
Reflections from an expert
As a preventive cardiologist whose entire career has been focused on primary, secondary, and tertiary prevention of CVD, I have embraced the use of beta-blockers as a mainstay of therapy in my patients with established CAD, regardless of ejection fraction. However, this new trial provides compelling evidence for a reconsideration.
Against our current backdrop of more-effective therapies and a change in general patient presentation (particularly from larger to smaller MIs at presentation), beta-blockers may no longer be necessary or even beneficial for secondary prevention and beyond in patients with preserved LVEF.
The impact of these new findings is likely to be quite similar to what we have seen—and continue to see—regarding the diminishing benefit of aspirin for CVD prevention,[] and for similar reasons: Advances in CVD treatment and prevention are making the old ways obsolete.
What this means for you
The findings of the REDUCE-AMI trial have important implications for cardiologists when managing patients with acute MI and preserved ejection fraction. While beta-blockers have long been a standard of care for secondary prevention of CVD, this study suggests that they may no longer provide significant benefits in the context of modern diagnosis and treatment methods. However, this study did not address the use of beta-blockers in patients with reduced ejection fraction or other cardiomyopathies, so beta-blocker use in these populations should continue per current guidelines.