The New England Journal of MedicineBeta-Blocker Interruption or Continuation after Myocardial Infarction

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The ABYSS trial, a multicenter, open-label, randomized, noninferiority study, investigated the safety and efficacy of interrupting long-term beta-blocker treatment in patients with a history of uncomplicated myocardial infarction. Conducted at 49 sites in France, the trial enrolled 3,698 patients with a left ventricular ejection fraction of at least 40% and no cardiovascular events in the previous 6 months. The study compared the interruption of beta-blocker therapy to its continuation, with a primary composite endpoint of death, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for cardiovascular reasons.

Key Points:

• The trial did not demonstrate noninferiority of beta-blocker interruption compared to continuation, with a primary outcome event occurring in 23.8% of patients in the interruption group versus 21.1% in the continuation group (hazard ratio 1.16; 95% CI, 1.01 to 1.33).
• Beta-blocker interruption did not improve patients’ quality of life as measured by the European Quality of Life–5 Dimensions questionnaire.
• The median time between the last myocardial infarction and randomization was 2.9 years, with a median follow-up of 3.0 years.
• Hospitalization for cardiovascular causes occurred in 18.9% of patients in the interruption group compared to 16.6% in the continuation group.
• The study population was representative of the French population and similar to other European nations, with 63% having a previous ST-segment elevation myocardial infarction.
• Crossover from one strategy to the other occurred in 5.7% of patients, more frequently in the interruption group (8.6%) than in the continuation group (2.8%).
• The results challenge current beliefs and recommendations suggesting the discontinuation of beta-blockers after one year in certain patient groups with a history of myocardial infarction.

“Our results should be considered within the context of the recent results of the open-label REDUCE-AMI (Randomized Evaluation of Decreased Usage of Beta-Blockers after Acute Myocardial Infarction) registry-based trial, which suggested that oral beta-blockers that were initiated during the acute phase of myocardial infarction did not lead to a lower risk of death or new myocardial infarction, a finding that is consistent with our own results regarding these end points.”

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