The ABYSS trial has cast further doubt on the necessity of continuing beta-blocker treatment in patients with a history of myocardial infarction (MI) and preserved ejection fraction. Presented at the European Society of Cardiology (ESC) Congress 2024, the trial, while not demonstrating safety preservation with beta-blocker interruption, also failed to show any significant benefit in quality of life.
Study Design and Patient Population
The open-label, non-inferiority, randomized trial enrolled 3,698 patients from 49 sites in France. Participants had a history of prior MI, were taking long-term beta-blockers, had a left ventricular ejection fraction of at least 40%, and had no cardiovascular events in the preceding 6 months. The mean age of the cohort was 63.5 years, with 17.2% being women. The median time between MI and randomization was 2.9 years, and the median follow-up was 3.0 years.
Key Findings
The primary outcome, a composite of death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for cardiovascular reasons, occurred in 23.8% of the interruption group and 21.1% of the continuation group (risk difference, 2.8 percentage points; 95% CI, <0.1 to 5.5; HR, 1.16; 95% CI, 1.01 to 1.33; P = .44 for noninferiority). The mean change in quality of life, as measured by the European Quality of Life–5 Dimensions (EQ-5D) questionnaire, was similar in both groups.
Individual components of the primary outcome revealed similar rates of death (4.1% vs 4.0%), myocardial infarction (2.5% vs 2.4%), and stroke (1.0% vs 1.0%) in the interruption and continuation groups, respectively. However, hospitalization for cardiovascular causes was more frequent in the interruption group (18.9%) compared to the continuation group (16.6%).
Expert Commentary
Principal investigator Johanne Silvain, MD, PhD, head of Department of Cardiology at the Pitié-Salpêtrière University Hospital, stated that the increased hospitalization for cardiovascular reasons and the lack of quality-of-life improvement do not support the interruption of chronic beta-blocker treatment in post-MI patients. She emphasized the need to consider these results in the context of other trials, such as the REDUCE-MI trial, to gain a more comprehensive understanding of optimal beta-blocker use after MI.
Tomas Jernberg, MD, PhD, professor of Cardiology at the Karolinska Institute, cautioned against overinterpreting the ABYSS and REDUCE-AMI trials, advocating for waiting for results from additional ongoing trials before definitively updating guidelines. He anticipates that these trials will provide more conclusive evidence regarding beta-blocker treatment in this patient population.
