Reference values for epicardial adipose tissue: data from 27,500 CT scans in the general population and symptomatic patients.

BACKGROUND

Increased epicardial adipose tissue volume (EATV) is a potentially important risk marker for coronary artery disease (CAD) available from cardiac computed tomography (CT) images. Sex differences and effects of age and body size on EATV have been insufficiently explored, and no reliable reference values exist. Consequently, EATV has yet to find its deserved use in clinical practice.

OBJECTIVES

To define normal values by sex and age, the best normalization procedure for EATV to neutralize effects of body size, explore the relationship between normalized EATV and cardiac risk, and propose a clinically meaningful cut-off.

METHODS

AI-based automated EATV data from the general population (n = 25,155) and a clinical cohort (n = 2,482) with suspected CAD was normalized to height, BSA and heart volumes. Correlation between EATV and EAT attenuation (EATA) was tested with Spearman's rank correlation and linear regression to find the optimal normalization. Normalized EATV was compared to high-risk by SCORE2 and obstructive CAD in the population cohort. A cut-off including 95% of cases with obstructive CAD was defined in the general population and tested in the clinical cohort.

RESULTS

EATV varied with sex and age across cohorts. Normalization of EATV to total heart volume (EATVh) improved correlation with EATA and successfully neutralized sex differences. High-risk by SCORE2 and the prevalence of obstructive CAD increased over quartiles of EATVh in the population cohort, and significantly higher EATVh was seen with obstructive CAD in both cohorts. A cut-off of 0.1 in EATVh had a negative predictive value for obstructive CAD of 97.1% in the general population and 88.9% in the clinical cohort.

CONCLUSIONS

EATV varies considerably with sex, age and body size. EATVh is largely sex-neutral and likely reflects true EAT expansion better than absolute EATV. EATVh is a potentially useful marker of obstructive CAD in both the general population and symptomatic patients.