Relationship Between β-blocker Therapy At Discharge And Clinical Outcomes In Patients With Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention

Objective: We sought to evaluate the impact of β-blocker therapy on clinical outcomes in patients with ACS after PCI and specified subgroups in a “real-world” clinical setting.Method: A total of 3180 eligible patients with acute coronary syndrome undergoing percutaneous coronary intervention were consecutively enrolled from March 1,2009 to December 31,2014.All participants were prospectively contacted at 1,6,and 12 months.We defined the primary end point as cardiogenic death and the secondary end point as a composite of cardiogenic death,nonfatal myocardial infarction,heart failure readmission,and cardiogenic hospitalization.We divided patients into two groups with regard to whether β-blocker therapy was received at discharge,and compared the relative risks between groups.We also calculated the proportion of β-blocker dose administered(daily dosage of β-blockers/target dose,and the target dose was in line with β-blocker doses used in large randomized trials),and participants were further compared with respect to the following: no β-blocker use,<50% of target dose,and ≥50% of target dose.Results: Compared with the no β-blocker group,the risk of cardiogenic death was significantly lower in the β-blocker group(hazard ratio [HR],0.33;95% CI,0.17–0.65 [P=0.001]).A consistent result was obtained in multiple adjusted model and propensity score–matched analysis.The use of β-blockers was also associated with decreased risk of composite of adverse cardiovascular events(HR,0.47;95% CI,0.28–0.81 [P=0.006]),although statistical significance disappeared after multivariable adjustment and propensity score matching.Furthermore,the post hoc analysis for the subsets of patients revealed that patients with non–ST segment elevation myocardial infarction benefited the most from β-blocker therapy at discharge(HR,0.04;95% CI,0.00–0.27 [P=0.001]),and the use of <50% of target dose was significantly associated with better outcome compared with no β-blocker use,rather than ≥50% of target dose.Conclusions: The administration of relatively low β-blocker dose is associated with improved clinical outcomes among patients with acute coronary syndrome after successful percutaneous coronary intervention,especially for patients with non-ST-segment elevation myocardial infarction.