The ideal length of beta-blocker treatment following a heart attack, or myocardial infarction (MI), remains uncertain for patients not requiring these medications for other health issues. The ABYSS trial found that stopping beta-blockers did not show any cardiovascular safety when compared to continuing the medication, nor did it enhance patients’ quality of life. Thus, the ABYSS trial indicates that long-term use of beta-blockers is advisable after an MI, even if the patient does not have heart failure, arrhythmia, or uncontrolled high blood pressure.
Research presented on August 30 at ESC Congress 2024 highlighted that there was no evident cardiovascular safety when beta-blockers were interrupted compared to their continuation in patients with a history of myocardial infarction (MI). Furthermore, the interruption did not lead to improvements in patients’ quality of life.1
The management methods for MI have advanced, leading healthcare providers to question the necessity of continuing beta-blockers after the first year post-MI, especially since ongoing treatment could result in side effects. To address this, we carried out the ABYSS trial to obtain clear randomized data on the impacts of stopping versus continuing beta-blocker therapy on cardiovascular events and quality of life. However, we did not find any preserved safety concerning clinical outcomes, nor any positive impact on quality of life from interrupting beta-blockers,” stated Principal Investigator, Professor Johanne Silvain from Sorbonne University, Paris, France.
The ABYSS trial was an open-label, non-inferiority randomized study executed by the ACTION Group. It involved patients who had experienced a previous MI and were on long-term beta-blockers, possessing a left ventricular ejection fraction of 40% or more and no cardiovascular incidents in the last six months. Participants were randomly assigned (1:1) to either stop or continue taking beta-blockers.
The main outcome of interest was a combination of mortality, non-fatal MI, non-fatal stroke, or hospitalization due to cardiovascular issues over the longest follow-up period (at least 1 year). This was assessed for non-inferiority (defined as an absolute difference of <3 percentage points for the upper limit of the two-sided 95% confidence interval [CI]). The principal secondary outcome was the change in quality of life assessed through the European Quality of Life-5 Dimensions questionnaire.
A total of 3,698 patients were randomized from 49 sites across France. The average age of participants was 64 years, with 17% being female. The median duration from the last MI to randomization was 2.9 years (interquartile range 1.2-6.4 years).
During a median follow-up of 3 years, stopping long-term beta-blocker treatment was not proven to be non-inferior to continuing it. Primary outcome events occurred in 23.8% of those in the interruption group compared to 21.1% in the continuation group (with a risk difference of 2.8 percentage points; 95% CI <0.1-5.5), resulting in a hazard ratio of 1.16 (95% CI 1.01-1.33; p=0.44 for non-inferiority).
Mortality rates were 4.1% in the interruption group and 4.0% in the continuation group, while MI rates were 2.5% and 2.4%, respectively. Notably, cardiovascular-related hospitalizations were seen in 18.9% of the interruption group compared to 16.6% of the continuation group. Additionally, interrupting beta-blockers was associated with increases in both systolic and diastolic blood pressure and heart rate at the 6-month mark (all p<0.001 compared to the continuation group) and throughout the study duration. The quality of life did not improve for patients who stopped taking the beta-blockers.
In summary, Professor Silvain stated, “The differences in hospitalization rates for cardiovascular reasons, negative impacts on blood pressure, and lack of improvement in quality of life do not support the interruption of long-term beta-blocker therapy in patients post-MI. These findings should be considered alongside recent results from the open-label REDUCE-MI6 trial and ongoing studies aimed at establishing the best practices for using beta-blockers after MI.”
1 ‘Beta blocker interruption in patients with prior myocardial infarction: results of the ABYSS trial and effect on blood pressure and heart rate control’ is set to be presented during Hot Line 1 on Friday, August 30, in room London.
2 Holt A, Blanche P, Zareini B, et al. Impact of long-term beta-blocker treatment in stable patients post-myocardial infarction without heart failure: a national cohort study from Denmark. Eur Heart J. 2021;42:907-914.
3 Park CS, Yang H-M, Ki Y-J, et al. Identifying the long-term advantages of beta-blockers based on left ventricular ejection fraction at 1 year following acute myocardial infarction: insights from the KAMIR-NIH Registry. Circ Cardiovasc Interv. 2021;14:e010159.
4 Puymirat E, Riant E, Aissaoui N, et al. The role of β Blockers and mortality outcomes after myocardial infarction in non-heart failure patients: a multicenter prospective cohort study. BMJ. 2016;354:i4801.
5 Kim J, Kang D, Park H, et al. Long-term effects of β-blocker therapy on clinical outcomes after acute myocardial infarction in the absence of heart failure: a nation-wide cohort study. Eur Heart J. 2020;41:3521-3529.
6 Yndigegn T, Lindahl B, Mars K, et al. The use of beta-blockers post-myocardial infarction in patients with preserved ejection fraction. N Engl J Med. 2024;390:1372-1381.
