Efficacy of Long-Term β-Blocker Therapy for Secondary Prevention of Long-Term Outcomes After Coronary Artery Bypass Grafting Surgery

Abstract

Background— Conflicting results from recent observational studies have raised questions concerning the benefit of β-blockers for patients undergoing coronary artery bypass grafting (CABG). Furthermore, the efficacy of long-term β-blocker therapy in CABG patients after hospital discharge is uncertain. Methods and Results— The study included 5926 consecutive patients who underwent CABG and were discharged alive. The prevalence and consistency of β-blocker use were determined in patients with and without a history of myocardial infarction (MI). β-Blockers were always used in 1280 patients (50.9%) with and 1642 patients (48.1%) without previous MI after CABG. Compared with always users (n=2922, 49.3%), the risk of all-cause death was significantly higher among inconsistent β-blocker users (hazard ratio [HR], 1.96; 95% confidence interval [CI], 1.50–2.57), and never using β-blockers was associated with increased risk of both all-cause death (HR, 1.42; 95% CI, 1.01–2.00) and the composite of adverse cardiovascular events (HR, 1.29; 95% CI, 1.10–1.50). In the cohort without MI, the HR for all-cause death was 1.70 (95% CI, 1.17–2.48) in inconsistent users and 1.23 (95% CI, 0.76–1.99) in never users. In the MI cohort, mortality was higher for inconsistent users (HR, 2.14; 95% CI, 1.43–3.20) and for never users (HR, 1.59; 95% CI, 1.07–2.63). Consistent results were obtained in equivalent sensitivity analyses. Conclusions— In patients with or without previous MI undergoing CABG, the consistent use of β-blockers was associated with a lower risk of long-term mortality and adverse cardiovascular events. Strategies should be developed to understand and improve discharge prescription of β-blockers and long-term patient adherence.