Background: To compare patterns of coronary artery disease in British South Asian and White European men.
Methods: 41 South Asian and 42 European men (mean age 64+/-9 years) with coronary artery disease were studied. All had similar symptoms. Vessel reference diameter and degree of stenosis were calculated using quantitative coronary angiography. Extent of atherosclerotic disease in the LAD was assessed using calcification scores (CAC) measured by multislice Computed Tomography. Fasting bloods and blood pressure were measured. The LAD was subdivided into four 2.5 cm segments for analysis.
Results: Most atherosclerosis occurred in the proximal LAD segment, South Asian men had more proximal LAD stenosis than European men (50% vs. 37%, p=0.036), but CAC scores were similar. South Asians with CAC scores in the lowest tertile (0-22 HU), had significantly narrower LAD diameters than Europeans (2.8 mm vs. 3.8 mm, p=0.004, adjusted for body surface area and age). This ethnic difference was not explained by measured risk factors, including diabetes. In contrast, ethnic differences in LAD diameter were abolished in the upper tertiles of CAC scores (23-2416 HU) (South Asians: 3.0 mm, Europeans: 3.1 mm, p=0.6). Calcification scores were negatively correlated with LAD diameter in Europeans (rho=-0.38, p=0.016) but not in South Asians (rho=-0.06, p=0.72).
Conclusions: Increased LAD stenosis, despite equivalent levels of calcified disease, in South Asians is attributable to narrower arteries. Reduced LAD diameter is associated with advanced disease in Europeans but not in South Asians, indicative of ethnic differences in vascular remodelling.