Quantitative angiography in South Asians reveals differences in vessel size and coronary artery disease severity compared to Caucasians.

South Asians are one of the highest risk ethnic groups for development of coronary artery disease (CAD) mortality and morbidity. Previous studies have investigated whether South Asians exhibit differences in angiographic coronary artery disease compared to Caucasians, with inconsistent results. We conducted a retrospective observational study comparing South Asians undergoing cardiac catheterization at a tertiary care institution with Caucasians who underwent catheterization at the same time and location to assess whether South Asians demonstrated smaller coronary artery size and/or increased angiographic coronary artery disease. Demographic and laboratory data were retrospectively abstracted. Quantitative coronary angiographic analysis of all three coronary arteries was performed using the edge-detection method. South Asian patients were younger (57 versus 64 years, p=0.004) and showed higher prevalences of diabetes, dyslipidemia, and acute coronary syndrome compared with Caucasians (40% versus 16%, p=0.004; 65% versus 46%, p=0.04; and 37% versus 10%, p<0.001; respectively). South Asians exhibited smaller normalized proximal LAD luminal diameters (1.56 versus 1.72 mm/m(2), p=0.04) when compared to Caucasians. South Asians also displayed more severe CAD as determined by both increased mean percent stenosis in the proximal LAD and RCA segments (22.7% versus 11.1%, p=0.004; and 24.5% versus 13.9%, p=0.0001, respectively) as well as a higher number of patients with multiple diseased vessel segments. South Asians demonstrated more severe CAD compared to Caucasians undergoing cardiac catheterization as evidenced by smaller proximal LAD luminal diameters, higher mean percent stenosis per vessel, and more patients with multivessel disease. Further study is warranted to better define factors important in the development of CAD and inform risk stratification in this high-risk population.