摘要Objectives:To evaluate the effectiveness and safety of Qishen Yiqi Dripping Pill(QSYQ)in patients with acute coronary syndrome(ACS)after percutaneous coronary intervention(PCI).Methods:This multicentre prospective cohort study was conducted at 40 centers in China.Patients with ACS after PCI entered either the QSYQ or Western medicine(WM)groups naturally based on whether they had received QSYQ before enrollment.QSYQ group received QSYQ(0.52 g,3 times a day for 12 months)in addition to WM.The primary endpoint included cardiac death,non-fatal myocardial infarction,and urgent revascularization.The secondary endpoint included rehospitalization due to ACS,heart failure,stroke,and other thrombotic events.Quality of life was assessed by the Seattle Angina Questionnaire(SAQ).Results:A total of 936 patients completed follow-up of the primary endpoint from February 2012 to December 2018.Overall,487 patients received QSYQ and WM.During a median follow-up of 566 days(inter quartile range,IQR,517-602),the primary endpoint occurred in 46(9.45％)and 65(14.48％)patients in QSYQ and WM groups respectively[adjusted hazard ratio(HR)0.60,95％confidence interval(CI)0.41-0.90;P=0.013].The secondary endpoint occurred in 61(12.53％)and 74(16.48％)patients in QSYQ and WM groups,respectively(adjusted HR 0.76,95％CI 0.53-1.09;P=0.136).In sensitivity analysis,the results still demonstrated that WM combined with QSYQ reduced the risk of the primary endpoint(HR 0.67,95％Cl 0.46-0.98;P=0.039).Moreover,QSYQ improved the disease perception domain of the SAQ(P＜0.05).Conclusions:In patients with ACS after PCI,QSYQ combined with WM reduced the incidence of the primary endpoint.These findings provide a promising option for managing ACS after PCI and suggest the potential treatment for reducing the risk of primary endpoint included cardiac death,non-fatal myocardial infarction,and urgent revascularization through intermittent administration of QSYQ.(Registration No.ChiCTR-OOC-14005552)