Background: This 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.

Methods: This 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.

Results: In 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.

Conclusions: MAG 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.