Photo Credit: Nuttiwut Rodbangpong

Beta-blocker interruption after a myocardial infarction (MI) failed to meet non-inferiority criteria in the ABYSS trial. Discontinuation resulted in higher hospitalization rates among patients with MI and a preserved left ventricular ejection fraction (LVEF) as compared with continued treatment with a beta-blocker, particularly in patients with hypertension. Furthermore, no quality-of-life improvements were reported in the beta-blocker interruption arm.

The phase 3, non-inferiority ABYSS trial (NCT03498066) randomized 3,700 stabilized patients with a history of MI and a preserved LVEF (≥40%) 1:1 to beta-blocker interruption or continued treatment with a beta-blocker to assess the safety and effect on quality-of-life of the interruption strategy. The primary endpoint was a composite of death, MI, stroke, or hospitalization for cardiovascular reasons, with a minimal follow-up of 1 year.

After a median follow-up of 3.0 years, participants in the interruption arm had a slightly increased risk for experiencing one of the primary outcome events than participants in the continuation arm (23.8% vs 21.1%; HR 1.16; 95% CI 1.01–1.33; P non-inferiority =0.44). “This effect was driven by an increase in hospitalizations for cardiovascular reasons (18.9% vs 16.6%),” explained Prof. Johanne Silvain, MD, PhD, from Pitié-Salpêtrière University Hospital, in France.

Next, the authors observed no difference in quality-of-life scores between the two treatment arms, as was measured by the EQ5D-5L score. However, they researchers did note that participants in the interruption arm had a significantly higher systolic BP (+3.7%) and diastolic BP (+3.9%) at 6 months than those in the continuation arm. Similarly, the interruption strategy significantly increased the heart rate of these participants with a mean of 9.8 beats per minute (P<0.001) compared with baseline.

“We analyzed the primary endpoint as stratified by hypertension and saw that hypertensive patients in the interruption arm were more likely to have a primary outcome event than hypertensive patients in the continuation arm [adjusted HR 1.18; 95% CI 1.01–1.36; P=0.03], whereas this effect was not observed for non-hypertensive patients [adjusted HR 1.05; 95% CI 0.86–1.28; P=0.64],” Prof. Silvain concluded his talk.

In short, the ABYSS trial showed that beta-blocker interruption was not as safe as beta-blocker continuation, leading to a higher rate of hospitalizations among patients with MI and a preserved LVEF.

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