Jonathan Avrom Leipsic MD, Presenter: Speakers Bureau, General Electric Company Medical Advisory Board, General Electric Company

Namal Wijesinghe, Abstract Co-Author: Nothing to Disclose

Robert Boone, Abstract Co-Author: Nothing to Disclose

Cameron John Hague MD, Abstract Co-Author: Nothing to Disclose

Brett Heilbron MD, FRCPC, Abstract Co-Author: Research funded, General Electric Company

Krishnan Ramanathan, Abstract Co-Author: Nothing to Disclose

Carolyn Taylor MD, Abstract Co-Author: Nothing to Disclose

Ren Yuan MD, PhD, Abstract Co-Author: Nothing to Disclose

Jennifer Deryn Ellis MD, Abstract Co-Author: Nothing to Disclose

Amr Mohmmad Hassan Ajlan MD, Abstract Co-Author: Nothing to Disclose

Troy Labounty, Abstract Co-Author: Nothing to Disclose

James K. Min, Abstract Co-Author: Speakers Bureau, General Electric Company Medical Advisory Board, General Electric Company

South Asians(SA) are reported to have higher prevalence of coronary artery disease and higher mortality from myocardial infarction than Non South Asians (NSA).Smaller coronary artery size in SA has been proposed as a potential contributing factor for these adverse outcomes although this difference in coronary artery size has not been established.Our aim was to evaluate coronary artery luminal area and atherosclerotic disease burden between SA and NSA using CCTA.

88 self-identified SA individuals and 88 matched NSA individuals with prior 64-detector CCTA were identified.Patients were matched for gender, age, body surface area, and coronary dominance.All patients received 0.4 mg sublingual nitroglycerin prior to the CCTA. Assessment of the luminal area of the most proximal portion of each coronary artery (LM,LAD,LCX,RCA)was performed. All studies were analysed by two experienced physicians who were blinded to the patient demographics and ethnicity. The ostia of all vessels were analysed except when stenotic or suboptimal image quality would not allow it.Studies were also evaluated for the presence of plaque and obstructive disease (>50%).

88 subjects were included in both groups. There were no significant differences in age, gender, body surface area, or dyslipidemia, diabetes, hypertension and smoking history (P=NS for all). SA individuals had smaller coronary artery areas for all vessels ans significantly so for LAD, LCX, and RCA :Left main coronary artery: 17.4 +/- 4.7 mm2 vs.18.3 +/- 4.2 mm2 (p= 0.2) LAD: 12.0 +/- 3.5 mm2 vs. 13.3 +/- 3.6 mm2 (p =0.02). LCX: 10.6 + 3.7 mm2 vs.11.9 + 4.1 mm2 (p=0.03) .RCA- 12.5+/-5.0mm2 13.9 +/- 3.8 mm2 (p=0.03). The cohorts had the same burden of obstructive disease SA 11.5% vs NSA 11.5% (p=1.0) however SA had a higher prevalence of plaque SA 62.2% vs NSA 44.8% (p=0.04).

SA individuals have significantly smaller coronary arteries and a higher prevalence of coronary plaque compared to NSA despite being matched for age, gender, body surface area, and cardiac risk factors. These findings may play a role in the higher CAD related rate of morbidity and mortality experienced by South Asians as compared to Non South Asians.

SA have significatly smaller coronary arteries and a higher prevalence of plaque than NSA which may play a role in the higher CAD related morbidity and mortality in SA than NSA.

Leipsic, J, Wijesinghe, N, Boone, R, Hague, C, Heilbron, B, Ramanathan, K, Taylor, C, Yuan, R, Ellis, J, Ajlan, A, Labounty, T, Min, J, Coronary Artery Luminal Area and Plaque Burden in South Asians and Non-South Asians: A Coronary CT Angiography Evaluation.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11006158.html