Obesity-Conduit Selection and Effect on Outcomes of Coronary Artery Bypass Grafting

To evaluate how obesity affects outcomes in CABG patients, focusing on conduit selection.

Between 1993 and 2019, 13,120 patients undergoing isolated CABG were categorized as obese (body mass index [BMI], ≥30; n=5525, 42.1%) and nonobese (BMI, <30; n=7595, 57.9%). Demographics, operative data, and outcomes were compared, and BMI was analyzed as both a dichotomous and a continuous variable.

Obese patients were younger (median age, 66.6 years vs 70.0 years) but more likely to have diabetes, hypertension, and previous percutaneous coronary interventions (P<.001). The proportion of obese CABG patients rose from 30.5% in 1993 to 50.9% in 2010 and plateaued thereafter. Although obese patients received slightly more arterial grafts, bilateral internal mammary artery (BIMA) use was no different. In multivariable analyses, obesity was associated with higher risk of sternal wound infection (odds ratio, 1.94), extended hospital stay (hazard ratio, 1.11), and lower risk of reexploration for bleeding (odds ratio, 0.49); analyses based on continuous BMI were similar. Operative mortality risk (n=243, 1.9%) did not differ between groups (P=.67) but was associated with a nonlinear BMI effect (P=.005), with extremes of BMI having a higher risk. Obese patients had increased long-term mortality (P<.001), with the hazard increasing with higher BMI values (P<.001). Having more arterial grafts was associated with improved long-term survival (P<.001), and use of BIMA did notaffect infection risk by obesity status (P=.96 for interaction).

Obesity rates increased over time, affecting long-term CABG survival negatively, especially in patients with extreme BMI. The use of arterial conduits, such as BIMA, provided long-term protection without altering the risk for sternal wound infections between either group.