Epicardial adipose tissue volume, compositional plaque progression, and vulnerability in nonobstructive coronary artery disease

BACKGROUND: Inflammation is a driver of atherosclerosis and plaque vulnerability. Epicardial adipose tissue (EAT) accumulation is associated with inflammation. The aim of this study was, therefore, to explore the association between EAT volume, compositional plaque progression, and vulnerability in nonobstructive coronary artery disease (CAD). METHODS: We identified 31 individuals [median age 58 (52, 68) years, 42% women] from the Norwegian Registry of Invasive Cardiology with nonobstructive CAD undergoing clinically indicated serial cardiac computed tomography (CT) and coronary CT angiography (CCTA). EAT volume was measured at baseline by a semiautomatic analysis software. Patients were grouped according to lower or higher than median baseline EAT (b-EAT) volume. Plaque progression was quantified by CCTA as annual change in total and compositional plaque volume. Hypodense plaques were adjudicated as vulnerable plaques. RESULTS: Patients with high b-EAT volume had numerically lower calcium score, coronary artery segment involvement score, total coronary plaque burden, and increased prevalence of vulnerable plaques compared with patients with low EAT volume at baseline and follow-up, even if it did not reach statistical significance. Compared with patients with low b-EAT volume, patients with high b-EAT volume tended to have an annual regression in total plaque volume, while the proportion of vulnerable hypodense plaque volume increased. CONCLUSION: In nonobstructive CAD, patients with high b-EAT volume tended to have a regression of total plaque volume, but a transformation into a vulnerable plaque phenotype during follow-up. Whether lifestyle changes may improve prognosis in nonobstructive CAD needs to be confirmed in larger trials.