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ESC Congress 2024, Paris – A landmark study presented at the ESC Congress 2024 has raised critical questions about the necessity of continuing long-term beta-blocker therapy after a myocardial infarction (MI). The ABYSS trial, conducted by the ACTION Group, investigated the effects of interrupting beta-blocker therapy versus continuing it in patients with a history of MI, revealing that discontinuing beta-blockers did not offer cardiovascular safety or quality-of-life benefits.
Study Overview and Methodology
The open-label, non-inferiority ABYSS trial involved 3,698 patients from 49 sites across France. All participants had a prior MI, were on long-term beta-blocker treatment, had a left ventricular ejection fraction of at least 40%, and had no cardiovascular events in the previous six months. They were randomly assigned to either continue or interrupt their beta-blocker therapy.
The primary endpoint of the study was a composite of death, non-fatal MI, non-fatal stroke, or hospitalization for cardiovascular reasons, measured over a median follow-up of three years. Secondary endpoints included changes in quality of life, assessed via the European Quality of Life-5 Dimensions questionnaire.
Key Findings
The trial found no significant benefit to discontinuing beta-blockers. The primary outcome event occurred in 23.8% of patients 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) and a hazard ratio of 1.16 (95% CI 1.01-1.33; p=0.44 for non-inferiority).
Notably, interruptions were associated with higher rates of hospitalizations for cardiovascular reasons (18.9% vs. 16.6%) and increases in systolic and diastolic blood pressure and heart rate (all p<0.001 vs. continuation). Additionally, there was no improvement in the quality of life for those who interrupted their medication.
Expert Opinions
Professor Johanne Silvain from Sorbonne University, Paris, the principal investigator of the study, emphasized, “The ABYSS trial did not demonstrate any cardiovascular safety advantage or improvement in quality of life with beta-blocker interruption. Instead, we observed adverse effects on blood pressure and increased hospitalization rates.”
Context and Implications
These findings challenge current practices and align with recent discussions from the REDUCE-MI trial and ongoing studies. The results highlight the need for continued vigilance in the management of post-MI patients and suggest that the benefits of long-term beta-blocker therapy may outweigh the risks, at least in the context of this study.
Conclusion
In summary, the ABYSS trial provides substantial evidence against interrupting beta-blocker therapy in patients with a history of MI. The lack of safety benefits and the adverse effects observed support the continued use of beta-blockers to manage cardiovascular risk and maintain patient quality of life post-MI. Further research and ongoing trials will continue to refine our understanding of optimal post-MI treatment strategies.
