Background:Percutaneous coronary intervention (PCI) through transradial approach (TRA) has shown to be safe and effective as transfemoral approach (TFA) among unselected patients.However,very few studies have compared the outcomes between TRA and TFA specifically in patients with a history of coronary artery bypass grafting surgery (CABG).Methods:A total of 404 post-CABG patients who had undergone angiography or PCI were included in the study.The primary endpoint was defined as angiographic success and procedure success.The secondary endpoint was defined as in-hospital net adverse clinical events (NACEs),which included all cause of death,myocardial infarction (MI),stroke,repeat revascularization,and major bleeding.Patients were followed-up for 1-year.Major adverse cardiovascular events (MACEs),which included death,MI,and repeat revascularization,at 1-year follow-up were also compared.Results:The angiographic success was reached by 97.4％ in the TRA group compared with 100％ in the TFA group (P =0.02).The procedure success was achieved in 99.1％ in the TRA group and 97.9％ in the TFA group (P =0.68).The incidence rates of in-hospital NACE (2.7％ vs.2.7％,P =1.00) and 1-year MACE (11.5％ vs.12.0％,P =0.88) were similar between TRA and TFA.Meanwhile,TRA was associated with a lower rate of Bleeding Academic Research Consortium ≥2 bleeding (P =0.02).In patients undergoing graft PCI,the procedure success was similar between TRA and TFA (100.0％ vs.98.7％,P =1.00).The procedure time (25.0 min vs.27.5 min,P =0.53) was also similar.No significant difference was detected between TRA and TFA in terms of in-hospital NACE (0 vs.0,P =1.00)and 1-year MACE (21.4％ vs.10.3％,P =0.19).Conclusions:Compared with TFA,TRA had lower angiographic success but had a similar procedure success in post-CABG patients.TRA was also associated with decreased bleeding and shortened hospital stay.