Impact of Body Composition Indices on Ten-year Mortality After Revascularization of Complex Coronary Artery Disease (From the Syntax Extended Survival Trial)

Numerous studies have demonstrated a paradoxical association between higher baseline body mass index (BMI) and lower long-term mortality risk after coronary revascularization, known as the “obesity paradox”, possibly relying on the single use of BMI. The current study is a post-hoc analysis of the SYNTAX Extended Survival (SYNTAXES) trial, which is the extended follow-up of the SYNTAX trial comparing percutaneous coronary intervention (PCI) versus coronary artery bypass graft (CABG) in patients with left-main coronary artery disease (LMCAD) or three-vessel disease (3VD). Patients were stratified according to baseline BMI and/or waist circumference (WC). Out of 1,800 patients, 1,799 (99.9%) and 1,587 (88.2%) had available baseline BMI and WC data, respectively. Of those, 1,327 (73.8%) patients had High BMI (≥25 kg/m2), whereas 705 (44.4%) patients had High WC (>102 cm for men or >88 cm for women). When stratified by both BMI and WC, 10-year mortality risk was significantly higher in patients with Low BMI/Low WC (adjusted hazard ratio [HR]: 1.65; 95% confidence interval [CI]: 1.09 to 2.51), Low BMI/ High WC (adjusted HR: 2.74; 95% CI: 1.12 to 6.69), or High BMI/High WC (adjusted HR: 1.59; 95% CI: 1.11 to 2.27) compared to those with High BMI/Low WC. In conclusion, the “obesity paradox” following coronary revascularization would be driven by low long-term mortality risk of the High BMI/Low WC group. Body composition should be assessed by the combination of BMI and WC in the appropriate evaluation of the long-term risk of obesity in patients with LMCAD or 3VD.