Association Between β-Blockers and Outcome of Coronary Artery Bypass Grafting: Before and After 1 Year

Background: We evaluated the long-term outcomes of coronary artery bypass grafting (CABG) according to β-blocker therapy using landmark analysis. Although β-blockers have been shown to improve outcomes for ischemic heart disease, the long-term effects and optimal treatment duration of use after CABG remain unknown. Methods: From January 2001 to December 2014, 5382 CABG patients were stratified into 2 groups according to β-blocker therapy at discharge (β-blocker group: 3677 [68.3%], no β-blocker group: 1705 [31.7%]). Results: The primary outcome was all-cause death during 48 months of follow-up. Using propensity score-matched analysis, β-blocker therapy was associated with all-cause death during the 48-month follow-up (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.41-0.95; P =.03). The landmark analysis demonstrated that the effect of β-blockers on all-cause death was particularly significant within the first 12 months of therapy (HR, 0.37; 95% CI, 0.19-0.80; P =.01) but not after 12 months (HR, 0.92; 95% CI, 0.56-1.53; P =.77). Conclusions: The benefits of postdischarge β-blockers may be limited to 1 year after CABG, but further studies are required to confirm this finding.