Abstract： Background:The impact of sequential vein bypass grafting on clinical outcomes is less known in off-pump coronary artery bypass grafting (CABG).We aimed to evaluate the effects of sequential vein bypass grafting on clinical outcomes in off-pump CABG.Methods:From October 2009 to September 2013 at the Fuwai Hospital,127 patients with at least one sequential venous graft were matched with 127 patients of individual venous grafts only,using propensity score matching method to obtain risk-adjusted outcome comparison.In-hospital measurement was composite outcome of in-hospital death,myocardial infarction (MI),stroke,requirement for intra-aortic ballon pump (IABP) assistance and prolonged ventilation.Major adverse cardiac events (MACEs:Death,MI or repeat revascularization) and angina recurrence were considered as mid-term endpoints.Results:No significant difference was observed among the groups in baseline characteristics.Intraoperative mean blood flow per vein graft was 40.4 ml in individual venous grafts groups versus 59.5 ml in sequential venous grafts groups (P ＜ 0.001).There were no differences between individual and sequential venous grafts groups with regard to composite outcome of in-hospital mortality,MI,stroke,IABP assistance and prolonged ventilation (11.0％ vs.14.2％,P =0.45).Individual in-hospital measurement also did not differ significantly between the two groups.At about four years follow-up,the survival estimates free from MACEs (92.5％ vs.97.3％,P =0.36) and survival rates free of angina recurrence (80.9％ vs.85.5％,P =0.48) were similar among individual and sequential venous grafts groups with a mean follow-up of 22.5 months.In the Cox regression analysis,sequential vein bypass grafting was not identified as an independent predictor of both MACEs and angina recurrence.Conclusions:Compared to individual vein bypass grafting,sequential vein bypass grafting was not associated with an increase of either in-hospital or mid-term adverse events in patients undergoing off-pump CABG.