Epicardial Adipose Tissue from Computed Tomography: a Missing Link in Premature Coronary Artery Disease?

Abstract Purpose Epicardial adipose tissue (EAT) could contribute to the specific atherosclerosis profile observed in premature coronary artery disease (pCAD) characterized by accelerated plaque burden (calcified and non-calcified), high risk plaque features (HRP) and ischemic recurrence. Our aims were to describe EAT volume and density in pCAD compared to asymptomatic individuals matched on CV risk factors and to study their relationship with coronary plaque severity extension and vulnerability. Materials and Methods 208 patients who underwent coronary computed tomography angiography (CCTA) were analyzed. It included 104 consecutive individuals with premature pCAD (acute or stable obstructive CAD before the age of 45 years) and 104 controls, matched 1:1 on age, sex and cardiovascular risk factors. EAT volume, volume index (EATi) and density were measured with a semi-automated AI-based segmentation method and CAD-RADS V2.0 determined according to guidelines. EAT volume and density were compared across groups and associations with plaque burden and characteristics were investigated. Results EAT volume and EATi were significantly higher in patients with pCAD compared to matched controls (71.5mL/m² [45.7;99.8] vs. 58.5mL/m² [41.3;81.7] p=0.002), and EAT density was significantly lower in patients with pCAD compared to matched controls (-82UH [-87; -79] vs. -82 [-85; -78], p=0.025). EATi was found to be positively correlated with increasing number of plaques, stenosis severity, and HRP features. Conclusion Patients with premature CAD had EAT expansion with a higher lipid concentration, compared to controls matched for traditional risk factors. Increased EAT volume and low EAT density were imaging biomarkers related to severe and potentially vulnerable CAD features.