β-blocker therapy cannot be safely withdrawn in stable post-MI patients

This summary is based on the presentation of Johanne Silvain, MD, PhD (Paris, France) at the ESC Congress 2024 - Beta blocker interruption in patients with prior myocardial infarction: results of the ABYSS trial and effect on blood pressure and heart rate control.

Introduction and methods

It is unknown whether β-blocker therapy in uncomplicated stable post-MI patients with LVEF >40% can be safely withdrawn.The ABYSS (Assessment of β-blocker interruption 1 Year after an uncomplicated myocardial infarction on Safety and Symptomatic cardiac events requiring hospitalization) trial evaluated the safety of β-blocker interruption in patients with a history of MI.

The ABYSS trial was an academic, multicenter, open label, randomized, non-inferiority trial conducted in France in which 3700 stabilized post-MI patients (>6 months from the acute event) with LVEF >40% and who were chronically treated with β-blockers were randomized to interruption or continuation of beta blocker therapy. Patients were followed for at least 1 year, and a maximum of 5 years. The median follow-up period was 3.0 years (IQR: 2.0-4.0).

The primary outcome was composite of all-cause mortality, stroke, MI and hospitalization for cardiovascular reason.

Main results

• The incidence rate of the primary outcome was higher in the β-blocker interruption group compared with the β-blocker continuation group (23.8% vs. 21.1%; HR: 1.16; 95%CI: 1.01-1.33; P=0.44 for non-inferiority).
• Interruption of β-blocker therapy did not lead to an improvement in quality of life compared continuation of β-blocker therapy (between-group difference in EQ5D-5L score: 0.002; 95%CI: -0.008 to 0.012).
• There was no significant difference in the incidence rate of the secondary composite outcome of all-cause mortality, MI, stroke and hospitalizations for HF in the β-blocker interruption group compared with the β-blocker continuation group (10.0% vs. 8.9%; HR: 1.11; 95%CI: 0.88-1.39).
• Compared with the continuation group, there was an increase in the systolic BP (+3.7 mmHg), diastolic BP (+3.9 mmHg), resting heart rate (+9.8 bpm), and double product (systolic BP x heart rate; +1616 points) in the interruption group (All P<0.001).
• In patients with hypertension at baseline (43% of the study population), the incidence rate of the primary endpoint was 25.4% in the β-blocker interruption group and 21.7% in the β-blocker continuation group (adjusted HR: 1.18; 95%CI: 1.01-1.46; P=0.03).

Conclusion

In the ABYSS trial, interruption of long-term β-blocker therapy was not non-inferior to continuation of β-blocker therapy in post-MI patients with LVEF >40%. The strategy of β-blocker interruption led to a higher rate of the primary composite outcome, especially in patients with hypertension. Interruption of β-blocker therapy did not result in an improvement of quality of life compared with continuation of therapy, and resulted in an increase in blood pressure and resting heart rate. “There is a safety signal for this strategy”, according to Johanne Silvain, MD, PhD.

- Our reporting is based on the information provided at the ESC Congress 2024 -

The findings of this study were simultaneously published in N Engl J Med.