Abstract EP65: Left Coronary Artery Cross-sectional Area And Traditional Cardiovascular Risk Factors Among Asymptomatic South Asians: Results From The MASALA Study

Abstract

Background: South Asians have a higher atherosclerotic cardiovascular disease (ASCVC) burden than other race/ethnic groups that is not fully explained by traditional risk factors. Smaller coronary artery luminal diameter has been proposed as a potential reason for this higher risk among South Asians. A few studies have measured coronary artery diameter in South Asians demonstrating smaller coronary luminal diameter explained by smaller body size. However, these studies were done symptomatic individuals with high burden of coronary plaque, and stenosis and vascular tone is known to impact lumen diameter. No studies have measured coronary artery external diameters in asymptomatic South Asians. Methods: We analyzed data from 513 participants, between ages of 42 and 68 years, enrolled in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) Study (2016-2018). We analyzed coronary cross-sectional area (CSA) with thin slice non-contrast cardiac CT scans. This is equivalent to the outermost (adventitial) boundary measured with intravascular ultrasound of the coronary arteries. We computed mean CSA in the proximal and mid LAD segments perpendicular to the centerline of the vessel. We examined bivariate associations of traditional cardiovascular risk factors and coronary artery calcium (CAC) with LAD CSA. We then created multivariable models adjusted for age and sex to determine independent correlations with LAD CSA. Results: We used data from 285 men and 228 women with mean age 56±7 years. The overall mean LAD CSA was 22.8±6.8 mm 2 for men and 17.6±6.2 mm 2 for women. In bivariate analysis, higher LAD CSA was associated with male sex, and higher age, BMI, waist circumference, systolic and diastolic blood pressures, fasting glucose, total and LDL-cholesterol, CAC scores, statin medication use, and lower HDL-cholesterol. In multivariable models, only male sex (β 0.044, p<0.001), hypertension (β 0.024, p<0.001), and BMI (β 0.003 per kg/m 2 , p <0.001) were significantly associated with LAD CSA. High CAC was marginally associated with LAD CSA (CAC>100: B 0.015 p = 0.065) while age, diabetes, and cholesterol levels were not independently associated with LAD CSA. Conclusion: These preliminary results suggest that LAD CSA is highly correlated with sex, body size, and hypertension, but not other metabolic risk factors that are more aberrant among South Asians. Long-term follow-up will determine whether LAD CSA is an important contributor to cardiovascular disease events among South Asians.