BACKGROUND Dual antiplatelet therapy (DAPT) improves early post-operative graft patency, but the optimal DAPT strategy for the patients after coronary artery bypass grafting (CABG) has not been confirmed. We sought to evaluate the effect of aspirin plus ticagrelor versus aspirin plus clopidogrel on saphenous vein graft (SVG) patency within 1 year after CABG. METHODS Between October 2017 and December 2018, 147 consecutive patients undergoing elective CABG at Changhai Hospital were randomized into two groups: group AT, receiving aspirin 100 mg/d plus ticagrelor 2×90 mg/d; group AC, receiving aspirin 100 mg/d plus clopidogrel 75 mg/d. Both DAPTs should be administered within 24 h when clinical stability was ensured. 64-multislice computed tomography angiography (MSCTA) was used to assess the graft patency at 12 months after CABG.CYP2C19 gene variants were measured to assess the clopidogrel efficacy on graft patency. RESULTS Among the 147 participants who completed the study, one (0.7%) patient from the AC group died at 5 weeks after surgery due to severe infection. All other patients were treated with DAPT for 12 months and underwent 64-MSCTA according to schedule. There were no significant differences in pre-operative characteristics and intraoperative transit-time flow measurement findings between the two groups. Besides, no significant differences in the incidence of major adverse cardiac events (MACEs) and major bleeding were observed. A 64-MSCTA showed that SVG patency was 91.0% (141 of 155) in the AT group and 89.9% (161 of 179) in the AC group (P=0.751). No significant associations were found between different CYP2C19 genotypes and SVG patency (P>0.05). CONCLUSIONS Either aspirin plus ticagrelor or aspirin plus clopidogrel can maintain a fairly high graft patency rate in the early phase after CABG, regardless of CYP2C19 genotypes.