BackgroundThis study evaluated the association between bypass grafting with multiarterial grafts (MAG) and single arterial grafts (SAG) and all-cause mortality and major adverse cardiovascular and cerebrovascular events (MACCE), overall and across different patient subgroups from a Middle Eastern nation. MethodsThis single-center retrospective cohort study included 23,798 patients. MAG and SAG groups were balanced using inverse probability weighting (IPW). Associations between MAG and outcomes were assessed using Cox regression. A series of covariate-adjusted Cox models were conducted to evaluate the effect of MAG on outcomes at different levels of independent variables, including age, sex, and cardiovascular risk factors. ResultsIn the study population (73.9% were men, 65.11 ± 9.94 years), 986 patients (4.1%) underwent MAG. Compared with the SAG group, MAG had lower crude mortality (14.1% vs 21.6%) and MACCE (28.8% vs 34.7%) rates during a median follow-up of 9.23 years (quartile 1-quartile 3, 9.13-9.33 years). Although MAG was significantly associated with reduced risk of study outcomes at the univariate level, these associations disappeared after matching (all-cause mortality (IPW hazard ratio, 0.90; 95% CI, 0.67-1.22) and MACCEs (IPW hazard ratio, 0.94; 95% CI, 0.76-1.15). However, covariate-adjusted models indicated that MAG was associated with a significantly reduced risk of adverse events, particularly MACCEs, in men, younger patients, and those without risk factors. ConclusionsMAG was not associated with improved postsurgery outcomes among the total coronary artery bypass graft population. Our findings, however, should be interpreted in the context of a relatively low total institutional MAG burden. Choosing a second arterial conduit over saphenous vein grafts in specific patient subgroups might be reasonable. This hypothesis-generating finding should be investigated in future clinical trials in these patients.