The answer to whether or not long-term beta-blocker therapy is needed after a heart attack (myocardial infarction) is an unknown among those who don’t take beta-blockers for other reasons. However, the ABYSS Trail suggests that long-term therapy with beta-blockers is recommended after an MI, even in the absence of heart failure, arrhythmia, or uncontrolled hypertension.
The ABYSS Trial
During the open-label, non-inferiority, randomized ABYSS Trial, the cardiovascular safety of discontinuing beta-blockers could not be shown in comparison with continuation, and discontinuing beta-blocker therapy did not improve the quality of life in patients with a history of myocardial infarction (MI), according to research published in The New England Journal of Medicine that was presented at the ESC Congress 2024.
“Improvements in MI management and data from observational studies have led physicians to question whether continuing beta-blockers after 1-year post-MI is needed since unnecessary treatment may result in side effects. 2-5 We conducted the ABYSS trial to provide conclusive randomised data on the effects of beta-blocker interruption vs. continuation on cardiovascular events and quality of life, but we were unable to show safety preservation in terms of clinical events nor any benefit on quality of life with beta-blocker interruption,” said Principal Investigator, Professor Johanne Silvain of the Sorbonne University, Paris, France.
The Study
“The ABYSS trial, conducted by the ACTION Group, included patients with a prior MI taking long-term beta-blockers, with a left ventricular ejection fraction of at least 40% and no cardiovascular events in the previous 6 months. Participants were randomized (1:1) to interrupting or continuing their β-blocker medication”
“The primary endpoint was a composite of death, non-fatal MI, non-fatal stroke, or hospitalization for cardiovascular reasons at the longest follow-up (minimum, 1 year), according to an analysis of non-inferiorit. The main secondary endpoint was the change in quality of life as measured by the European Quality of Life–5 Dimensions questionnaire.”
“In total 3,698 patients were randomised from 49 sites in France. The mean age was 64 years and 17% were female. The median time between last MI and randomisation was 2.9 years (interquartile range 1.2–6.4 years).”
“Over median follow-up of 3 years, interruption of long-term beta-blocker treatment was not shown to be non-inferior to beta-blocker continuation. A primary-outcome event occurred in 23.8% of patients in the interruption group and in 21.1% in the continuation group (risk difference 2.8 percentage points; 95% CI <0.1–5.5), with a hazard ratio of 1.16 (95% CI 1.01–1.33; p=0.44 for non-inferiority).”
“Death occurred in 4.1% in the interruption group and 4.0% in the continuation group, while MI occurred in 2.5% and 2.4%, respectively. Of note, hospitalisation for cardiovascular causes occurred in 18.9% in the interruption group and 16.6% in the continuation group. Beta-blocker interruption 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 the study follow up. Beta-blocker interruption did not improve the patients’ quality of life.”
Conclusions
Given the overall findings and limitations of this study, Silvain cautions that these findings “do not support interruption of a chronic beta-blocker treatment in post-MI patients” and “must be put into context with recent findings from the open-label REDUCE-MI trial and ongoing trials to provide additional evidence on the optimal use of beta-blockers after MI.”
Professor Silvain concluded that: “Differences between the groups with respect to hospitalisation for cardiovascular reasons and the negative effect on blood pressure levels, together with the absence of quality-of-life improvement do not support interruption of a chronic beta-blocker treatment in post-MI patients. These results must be put into context with recent findings from the open-label REDUCE-MI6 trial and ongoing trials to provide additional evidence on the optimal use of beta-blockers after MI.”
Editorial
In an editorial comment published in NEJM Tomas Jernberg, MD, PhD, agrees, that: “it is prudent to wait for the results of additional ongoing trials of beta-blockers involving patients with [MI] and a preserved left ventricular ejection fraction before definitively updating guidelines. He adds: “Taken together, the results of the ABYSS, REDUCE-AMI, and ongoing trials will most likely provide firm evidence regarding beta-blocker treatment in this patient population.”
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References/Sources/Materials provided by:
http://www.nejm.org/doi/full/10.1056/NEJMoa2404204
http://www.nejm.org/doi/full/10.1056/NEJMe2409646
https://www.acc.org/Latest-in-Cardiology/Clinical-Trials/2024/08/29/03/43/abyss
https://www.acc.org/Latest-in-Cardiology/Features/Meeting-Coverage/2024/ESC-2024-Meeting-Coverage
