Abstract 5746: Risk Categorization and Lipid Lowering Eligibility according to NCEP ATP III Guidelines across Increasing Atherosclerotic plaque Burden Assessed by Non Invasive Coronary CT Angiography
Back-ground: Coronary computed tomography angiography (CCTA) is a promising noninvasive tool for assessment of atherosclerotic plaque burden and significant coronary heart disease (CHD). The purpose of this study was to investigate the classification of CHD risk in asymptomatic individuals as well eligibility for lipid lowering medications (LLM) according to the National Cholesterol Education Program (NCEP) guidelines across a continuum of CCTA findings.
Methods: The study population consisted of 986 asymptomatic men (n=627, 64%) and women (n=359, 36%) not on LLM who were assessed with 64-slice multidetector CCTA. We categorized participants according to NCEP into low-risk (0 –1 risk factors), intermediate-risk (≥2 risk factors but <10% risk of CHD at 10 years), moderately high-risk (≥2 risk factors and 10 –20% risk of CHD in 10 years) or high-risk (≥2 risk factors and >20% risk of CHD in 10 years) groups according to NCEP guidelines.
Results: In our study no coronary plaque was seen in 826 (79%) of the study population, whereas 115 (11%) and 102 (10%) had 1 and ≥2 segments with atherosclerotic plaques. Nearly one third of individuals (30%) with ≥2 segments with coronary plaque were considered low risk; with 22% and 47% considered intermediate and moderately high risk, and only 1% were classified as high risk. Interestingly, 27% of the participants with ≥50% luminal diameter stenosis as well those with 2–3 vessels with significant CHD (21%), were classified as low risk according to the NCEP guidelines. When considered according to increasing degree of luminal stenosis, 76% with ≥50% stenosis also did meet eligibility criteria for pharmacotherapy. With the same level of atherosclerotic burden (≥2 coronary segments with plaque), higher proportion of women vs. men (86% vs. 68%) as well as younger vs. older (74% vs. 67%) were not eligible for LLM according to NCEP guidelines.
Conclusion: Our study provides further evidence regarding the limitation of NCEP guidelines in misclassifying CHD risk in asymptomatic individuals, especially women and the young. For these individuals, assessment of plaque burden could help refine risk assessment; however utility of CCTA beyond non-contrast CT based coronary calcium scores in asymptomatic individuals is not yet established.