Differing effects of beta-blockers on long-term clinical outcomes following percutaneous coronary intervention between patients with mid-range and reduced left ventricular ejection fraction

BACKGROUND: The aim of this study was to determine the difference in effects of beta-blockers on long-term clinical outcomes between ischemic heart disease (IHD) patients with mid-range ejection fraction (mrEF) and those with reduced ejection fraction (rEF). METHODS: Data were assessed of 3508 consecutive IHD patients who underwent percutaneous coronary intervention (PCI) between 1997 and 2011. Among them, 316 patients with mrEF (EF = 40-49%) and 201 patients with rEF (EF < 40%) were identified. They were assigned to groups according to users and non-users of beta-blockers and effects of beta-blockers were assessed between mrEF and rEF patients, separately. The primary outcome was a composite of all-cause death and non-fatal acute coronary syndrome. RESULTS: The median follow-up period was 5.5 years in mrEF patients and 4.3 years in rEF patients. Cumulative event-free survival was significantly lower in the group with beta-blockers than in the group without beta-blockers in rEF (p = 0.003), whereas no difference was observed in mrEF (p = 0.137) between those with and without beta-blockers. In the multivariate analysis, use of beta-blockers was associated with reduction in clinical outcomes in patients with rEF (hazard ratio (HR), 0.59; 95% confidence interval (CI), 0.36-0.97; p = 0.036), whereas no association was observed among those with mrEF (HR 0.74; 95% CI 0.49-1.10; p = 0.137). CONCLUSIONS: Our observational study showed that use of beta-blockers was not associated with long-term clinical outcomes in IHD patients with mrEF, whereas a significant association was observed in those with rEF.