The effect of obesity on survival in patients undergoing coronary artery bypass graft surgery who receive a radial artery

OBJECTIVES: The radial artery (RA) is often used as a second arterial conduit in preference to the right internal thoracic artery in obese patients undergoing coronary artery bypass grafting (CABG) to minimise the risk of sternal wound complication. However, obesity has been found to promote RA vasoreactivity and early atherosclerotic degeneration, which may compromise graft patency when used in patients having CABG. Therefore, we investigated the effect of the RA as a second conduit compared with the saphenous vein (SV) on long-term survival in obese and non-obese patients undergoing first-time CABG.METHODS: Propensity score matching was used to adjust for imbalance, and the effect of the RA in obese (body mass index, BMI ≥ 30) and non-obese (BMI < 30) participants was tested by means of time-segmented Cox regression.RESULTS: The study population comprised 12 244 patients undergoing first-time CABG. Of those, 8740 patients were non-obese and 3504 were obese. The RA was used as a second arterial conduit in 1322 (15%) non-obese patients and in 685 (20%) obese patients. The use of the RA compared to the SV reduced the risk of late death in patients with BMI < 30 (HR 0.78; 95% CI 0.65-0.94; P = 0.008) but not in those with BMI ≥ 30 (HR 1.05; 95% CI 0.80-1.38; P = 0.72), regardless of their diabetes status (non-diabetic HR 0.87 [0.63-1.20] vs diabetic HR 0.83 [0.54-1.26]; interaction P = 0.8).CONCLUSIONS: The use of the RA in preference to the SV as a second conduit was associated with improved long-term survival in non-obese patients undergoing CABG. This benefit was no longer present in obese patients regardless of their diabetes status.