Cardiovascular safety of stopping beta-blocker treatment compared with continuing it in patients with a history of myocardial infarction (MI) could not be demonstrated and there was no benefit to patients’ quality of life, according to late-breaking research presented on 30 August at ESC Congress 2024.1
“Improvements in the treatment of myocardial infarction and data from observational studies have led physicians to question whether it is necessary to continue taking beta-blockers one year after myocardial infarction, since unnecessary treatment can cause side effects.2-5 “We conducted the ABYSS trial to provide conclusive randomised data on the effects of beta-blocker discontinuation versus continuation on cardiovascular events and quality of life, but we were unable to demonstrate preservation of safety in terms of clinical events or any benefit in quality of life with beta-blocker discontinuation,” said lead investigator Professor Johanne Silvain of Sorbonne University, Paris, France.
The ABYSS trial, an open-label, randomized, noninferiority trial conducted by the ACTION Group, included patients with a prior myocardial infarction who were taking long-term beta-blockers, with a left ventricular ejection fraction of at least 40% and without cardiovascular events in the previous 6 months. Participants were randomly assigned (1:1) to discontinue or continue their beta-blocker medication.
The primary endpoint was a composite of death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for cardiovascular reasons at longest follow-up (minimum, 1 year), based on noninferiority analysis (defined as an absolute difference between groups of <3 percentage points for the upper limit of the two-sided 95% confidence interval). [CI]). The primary secondary endpoint was change in quality of life measured using the European 5-Dimensional Quality of Life Questionnaire.
In total, 3698 patients from 49 centres in France were randomised. The mean age was 64 years and 17% were women. The median time elapsed between the last myocardial infarction and randomisation was 2.9 years (interquartile range: 1.2-6.4 years).
During a median follow-up of 3 years, discontinuation of long-term beta-blocker therapy was not shown to be noninferior to continuation of beta-blocker therapy. A primary outcome event occurred in 23.8% of patients in the discontinuation group and 21.1% in the continuation group (risk difference 2.8 percentage points; 95% CI <0.1-5.5), for a hazard ratio of 1.16 (95% CI 1.01-1.33; p=0.44 for noninferiority).
Death occurred in 4.1% of the discontinuation group and 4.0% of the continuation group, whereas myocardial infarction occurred in 2.5% and 2.4%, respectively. Of note, hospitalization for cardiovascular causes occurred in 18.9% of the discontinuation group and 16.6% of the continuation group. Beta-blocker discontinuation was also associated with increases in systolic and diastolic blood pressure and heart rate at 6 months (all p < 0.001 vs. beta-blocker continuation) and during study follow-up. Beta-blocker discontinuation did not improve patients' quality of life.
Summarizing the evidence from the ABYSS trial, Professor Silvain concluded: “The differences between the groups with regard to hospitalization for cardiovascular reasons and the negative effect on blood pressure levels, together with the absence of improvement in quality of life, do not support the discontinuation of chronic beta-blocker treatment in patients who have suffered a myocardial infarction. These results should be put into context with the recent findings from the open-label REDUCE-MI study.”6 “Ongoing clinical trials and trials to provide additional evidence on the optimal use of beta-blockers after myocardial infarction.”
‘Discontinuation of beta-blockers in patients with prior myocardial infarction: results from the ABYSS trial and effect on blood pressure and heart rate control’ will be discussed during Hotline 1 on Friday 30 August in the London Room.
2 Holt A, Blanche P, Zareini B, et al. Effect of long-term beta-blocker therapy after myocardial infarction in stable, optimally treated patients without heart failure in the reperfusion era: a Danish nationwide cohort study. Eur Heart J. 2021;42:907-914.
3 Park CS, Yang HM, Ki YJ, et al. Left ventricular ejection fraction at 1 year after acute myocardial infarction identifies benefits of long-term beta-blocker use: analysis of data from the KAMIR-NIH Registry. Circ Cardiovasc Interv. 2021;14:e010159.
4 Puymirat E, Riant E, Aissaoui N, et al. β-blockers and mortality after myocardial infarction in patients without heart failure: a multicentre prospective cohort study. BMJ. 2016;354:i4801.
5 Kim J, Kang D, Park H, et al. Long-term beta-blocker therapy and clinical outcomes after acute myocardial infarction in patients without heart failure: a nationwide cohort study. Eur Heart J. 2020;41:3521–3529.
6 Yndigegn T, Lindahl B, Mars K, et al. Beta-blockers after myocardial infarction and preserved ejection fraction. N Engl J Med. 2024;390:1372-1381.