Obesity is associated with an increased risk of cardiovascular disease and may be associated with more severe coronary artery disease (CAD); however, the relationship between body mass index (BMI) and CAD severity remains controversial. The aim of this study was to investigate the relationship between BMI and severity of CAD according to syntax score (SS) and syntax score II (SSII).

From January 1st to June 30th 2017, we prospectively enrolled consecutive CAD patients who underwent percutaneous intervention (PCI). BMI was classified into 3 groups: normal (18.5≤BMI<25), overweight (25≤BMI<30) and obesity (BMI≥30). SS and SSII were calculated in all patients by the consensus of two experienced interventional cardiologists.

A total of 305 patients who underwent 327 PCI were enrolled into the study. Overall, obesity was prevalent in 9.2% of patients (n=28). Cardiac risk factors (hypertension, dyslipidemia, CKD) were similar between the different BMI groups, except diabetes which was significantly higher in the obese group compared with overweight and normal weight groups (78.6% vs. 58.9% and vs. 43.3%; P=0.046 and P=0.001, respectively). Obese patients had a tendency towards more single-vessel involvement (60.7%), required shorter stents in comparison with overweight and normal BMI groups (4.8mm and 4.7mm shorter, respectively). Obese patients were less often completely revascularized (53.6% vs. 63.3% vs. 59.8%; in the obese, overweight and normal BMI groups, respectively). SS was lower in the obese group, no significant correlation between SS and BMI was observed (r=−0.050, P=0.388). SS II was inversely proportional to BMI (r=−0.124, P=0.031).

Despite higher prevalence of diabetes, obese patients might have less severe and less complex CAD than normal BMI and overweight patients, in terms of number of involved vessels, length of stents and SSII.