The Relationship Between Left Atrial Epicardial Adipose Tissue Volume and Coronary Microvascular Dysfunction in Patients with Non-Obstructive Coronary Artery Disease

Abstract

Objective To investigate whether epicardial adipose tissue (EAT) volume correlates with coronary microvascular dysfunction (CMD) identified via invasive physiological evaluation, in comparison with EAT attenuation. Materials and Methods This retrospective study included 158 consecutive patients (mean age 65.40±9.76 years, 51.90% male) who underwent both coronary computed tomography angiography (CCTA) and invasive coronary function testing. CMD was defined as coronary flow reserve (CFR) <2.0 and/or index of microcirculatory resistance (IMR) ≥25. Total EAT volume, left atrial (LA)-EAT volume, and right atrial (RA)-EAT volume, EAT attenuation, and coronary fat attenuation index (FAI) were quantified from CCTA images. Multivariable logistic regression analyses were performed to screen variables associated with CMD. Results CMD was diagnosed in 59 patients (37.34%). Patients with CMD had significantly higher total EAT volume, LA-EAT volume, and RA-EAT volume (all P <0.001) compared with patients without CMD. After adjustment for age, sex, BMI, and cardiovascular risk factors, total EAT volume (OR=1.134, 95% CI 1.089–1.181, P <0.001), LA-EAT volume (OR=1.006, 95% CI 1.004–1.008, P <0.001) and RA-EAT volume (OR=1.003, 95% CI 1.002–1.005, P <0.001) were independently associated with CMD. The FAI of the three major coronary arteries showed no significant association with CMD (all P >0.05). LA-EAT volume demonstrated excellent discriminative ability for CMD (AUC=0.917), which was superior to total EAT volume (AUC=0.824) and RA-EAT volume (AUC=0.846). DeLong test analysis confirmed that the AUC of LA-EAT volume was significantly higher than that of total EAT volume (P=0.003) and of RA-EAT volume (P=0.029). No significant difference was observed between the AUCs of total EAT volume and RA-EAT volume (P =0.547). Conclusion Total and atrial-specific EAT volumes, particularly LA-EAT volume, are strongly and independently associated with CMD, whereas FAI shows no association with coronary microvascular dysfunction. EAT volume measurements acquired from routine CCTA may act as a valuable imaging biomarker for CMD-related risk stratification. LA-EAT measurement obtained from routine CCTA is promising for convenient clinical screening of coronary microvascular dysfunction.