Stopping Beta Blockers After Myocardial Infarction

Key Takeaways

• Discontinuation was noninferior to continuation for the composite outcome studied.
• Stable post-MI patients with a left ventricular ejection fraction of at least 40% and no heart failure were randomized after at least 1 year of therapy to stop or continue beta blockers.
• Median follow-up was 3.1 years, and serious adverse events were similar between groups.

In stable patients after myocardial infarction who had a left ventricular ejection fraction of at least 40% and no heart failure, stopping chronic beta blocker therapy after the first year was noninferior to continuing it for the composite outcome studied. In the SMART-DECISION trial in NEJM, the hazard ratio was 0.80, with a 95% CI of 0.57 to 1.13. This randomized noninferiority trial enrolled adults who remained stable after MI after at least 1 year of prior beta blocker therapy. Eligible patients had a left ventricular ejection fraction of at least 40% and no heart failure. The comparison addressed whether beta blocker therapy needed to extend beyond the first post-MI year.

The role of long-term beta blocker therapy after MI remains unclear in the era of contemporary reperfusion and secondary prevention, which prompted the trial. SMART-DECISION was an open-label randomized noninferiority trial conducted at 25 centers in South Korea. Patients were randomly assigned in a 1:1 ratio to discontinue or continue beta blocker therapy after chronic use. A total of 2540 patients were randomized, with 1246 assigned to discontinuation and 1294 to continuation. The cohort had a mean age of 63.2 years, 12.8% were women, and the protocol prespecified the primary endpoint and the statistical framework for noninferiority.

The primary endpoint was a composite of death from any cause, recurrent myocardial infarction, or hospitalization for heart failure. Noninferiority was prespecified as an upper 95% confidence limit for the hazard ratio of 1.4. The primary endpoint occurred in 58 patients in the discontinuation group and 74 in the continuation group. The 4-year Kaplan-Meier estimates were 7.2% with discontinuation and 9.0% with continuation, and the noninferiority analysis yielded P=0.001. Discontinuation met the prespecified noninferiority criterion for the composite outcome beyond the first year.

Median follow-up was 3.1 years, with an interquartile range of 2.5 to 3.5 years. Serious adverse events were similar in the two groups. In this stable post-MI cohort with a left ventricular ejection fraction of at least 40% and no heart failure at centers in South Korea, discontinuation beyond the first year was noninferior to continuation for the composite outcome studied.