Background The benefits of long-term maintenance beta-blocker (BB) therapy in patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) have not been well established. Methods and Results Using the Korean nationwide registry, a total of 7159 patients with AMI treated with PCI who received BBs at discharge and were free from death or cardiovascular events for 3 months after PCI were included in the analysis. Patients were divided into 4 groups according to BB maintenance duration: <12 months, 12 to <24 months, 24 to <36 months, and ≥36 months. The primary outcome was the composite of all-cause death, recurrent MI, heart failure, or hospitalization for unstable angina. During a mean 5.0±2.8 years of follow-up, over half of patients with AMI (52.5%) continued BB therapy beyond 3 years following PCI. After propensity score matching and propensity score marginal mean weighting through stratification, a stepwise inverse correlation was noted between BB duration and risk of the primary outcome (<12 months: hazard ratio [HR], 2.19 [95% CI, 1.95-2.46]; 12 to <24 months: HR, 2.10 [95% CI, 1.81-2.43];, and 24 to <36 months: HR, 1.68 [95%CI, 1.45-1.94]; reference: ≥36 months). In a 3-year landmark analysis, BB use for <36 months was associated with an increased risk of the primary outcome (adjusted HR, 1.59 [95% CI, 1.37-1.85]) compared with BB use for ≥36 months. Conclusions Among stabilized patients with AMI following PCI, longer maintenance BB therapy, especially for >36 months, was associated with better clinical outcomes. These findings might imply that a better prognosis can be expected if patients with AMI maintain BB therapy for ≥36 months after PCI. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02806102.
Keywords: acute myocardial infarction; beta‐blocker; clinical outcome; percutaneous coronary intervention.