Comparative Effectiveness of Long‐Term Maintenance Beta‐Blocker Therapy after Acute Myocardial Infarction in Stable, Optimally Treated Patients Undergoing Percutaneous Coronary Intervention

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.