A new study has challenged the efficacy of long-term beta-blocker treatment following an acute myocardial infarction in patients with a preserved left ventricular ejection fraction.
The research, part of the Randomized Evaluation of Decreased Usage of Beta-Blockers after Acute Myocardial Infarction (REDUCE-AMI) trial, aimed to evaluate whether beta-blockers could decrease the risk of death from any cause or a new myocardial infarction in this patient demographic.
Historically, beta-blockers have been shown to reduce mortality in patients with heart failure and reduced ejection fraction, particularly those with significant myocardial infarctions and left ventricular systolic dysfunction, according to the study published in The New England Journal of Medicine. However, these findings predominantly stem from studies conducted in the 1980s before the advent of modern reperfusion techniques and other advanced treatments like high-intensity statins and renin–angiotensin–aldosterone system antagonists.
The study enrolled 5,020 patients from 45 centers who had recently undergone coronary angiography. Participants were randomly assigned to either continue with long-term beta-blocker therapy (using metoprolol or bisoprolol) or discontinue the use of beta-blockers. The primary focus was to observe the occurrence of death from any cause or new myocardial infarction over a median follow-up of 3.5 years.
The results, however, indicated no significant difference in the primary endpoint between the two groups. In the beta-blocker group, 7.9% of the patients experienced a primary endpoint event, compared to 8.3% in the no–beta-blocker group. Secondary endpoints, including death from cardiovascular causes, myocardial infarction, and hospitalization due to heart complications like atrial fibrillation and heart failure, also showed no significant difference between the groups.
These findings suggest that in the context of contemporary clinical practices, which include early revascularization and other advanced pharmacologic treatments, the benefit of beta-blockers may not be as pronounced as previously thought. "Our trial results suggest that beta-blockers do not offer a significant advantage in preventing death or myocardial infarction in patients who have a preserved ejection fraction post-myocardial infarction," stated the lead researcher from the Swedish Research Council.
Safety endpoints were similarly distributed between the groups, indicating no increased risk of hospitalization for conditions like bradycardia, hypotension, or stroke associated with beta-blocker use.
This study's implications are significant as they may influence current guidelines that generally recommend beta-blocker use post-myocardial infarction, noted the investigators. As the science of cardiology evolves, so too may the protocols for post-infarction patient care, especially concerning the use of beta-blockers in specific patient populations, they added. Further research is needed to explore the potential benefits of beta-blockers in subgroups and in different settings to ensure optimized patient outcomes.
The study was funded by the Swedish Research Council.
