Background and aims To determine whether epicardial (EAT) and paracardial adipose tissue (PAT) volume and attenuation are associated with high-risk coronary plaque features. Methods In subjects with suspected acute coronary syndrome (ACS) enrolled in the ROMICAT II trial, EAT and PAT volumes indexed to body surface area (BSA) and attenuation were measured on noncontrast coronary artery calcium score (CACS) CT. High-risk plaque features (napkin-ring sign, positive remodeling, low density plaque, spotty calcium) and stenosis were assessed on coronary CT angiography (CTA). The association of EAT and PAT volume and attenuation with high-risk plaque and whether this was independent of clinical risk assessment, CACS and significant coronary artery disease (CAD) was determined. Results Of 467 (mean 54±8 yrs, 53% male) with CACS and CTA, 167 (36%) had high-risk plaque features. Those with high-risk plaque had significantly higher indexed EAT (median 59 (Q1–Q3:45–75) cc/m2 vs. 49 (35–65) cc/m2, p <0.001) and PAT volume (median:51 (36–73) cc/m2 vs. 33 (22–52) cc/m2, p <0.001). Higher indexed EAT volume was associated with high-risk plaque [univariate OR 1.02 (95%-CI:1.01 – 1.03) per cc/m2 of EAT, p <0.001], which remained significant [univariate OR 1.04 (95%-CI:1.00–1.08) per cc/m2 of EAT, p=0.040] after adjustment for risk factors, CACS, and stenosis ≥50%. Higher indexed PAT volume was associated with high-risk plaque in univariate analysis [OR 1.02 (1.01 – 1.03) per cc/m2 of PAT, p <0.001], though this was not significant in multivariate analysis. At a threshold of >62.3 cc/m2, EAT volume was associated with high-risk plaque [univariate OR 2.50 (95%-CI:1.69–3.72), p <0.001)], which remained significant [OR 1.83 (95%-CI:1.10–3.05), p=0.020] after adjustment. Subjects with high-risk plaque had lower mean attenuation EAT (−88.1 vs. −86.9 HU, p=0.008) and PAT (−106 vs. −103 HU, p <0.001), though this was not significant in multivariable analysis. Conclusions Greater volumes of EAT are associated with high-risk plaque independent of risk factors, CACS and obstructive CAD. This observation supports possible local influence of EAT on development of high-risk coronary plaque.

Background The presence and extent of coronary artery calcium (CAC) are associated with increased risk for cardiovascular events. We determined whether information on the distribution of CAC and coronary dominance as detected by cardiac computed tomography (CT) were incremental to traditional Agatston score (AS) in predicting incident major coronary heart disease (CHD). Methods and Results We assessed total AS and the presence of CAC per coronary artery, per segment and coronary dominance by CT in participants from the Offspring and Third generation cohorts of the Framingham Heart Study. The primary outcome was major CHD (myocardial infarction or coronary heart disease death). We performed multivariable Cox proportional hazards analysis and calculated relative integrated discrimination improvement (rIDI). In 1268 subjects (mean age 56.2±10.3 years, 63.2% men) with AS >0 and no prior history of major CHD, a total of 42 major CHD events occurred during median follow of 7.4 years. The number of coronary arteries with CAC (hazard ratio: 1.68 per artery, 95% CI 1.10–2.57, p=0.02) and the presence of CAC in the proximal dominant coronary artery (HR 2.59, 95% CI 1.15–5.83, p=0.02) were associated with major CHD events after multivariable adjustment for Framingham risk score and categories of AS. In addition, measures of CAC distribution improved discriminatory capacity for major CHD events (rIDI 0.14). Conclusions Distribution of coronary atherosclerosis, especially CAC in the proximal dominant coronary artery and an increased number of coronary arteries with CAC, predict major CHD events independently of the traditional AS in community-dwelling men and women.