Objective: Epicardial adipose tissue is an emerging risk factor of coronary atherosclerosis. We sought to examine epicardial fat volume (EFV) measured by coronary computed tomography angiography (CCTA) has a predictive power of long-term coronary morbidity.
Methods: We studied 747 patients without proven coronary artery disease (CAD) who underwent coronary computed tomography angiography (CCTA). Body mass indexed EFV (iEFV) was simultaneously calculated. Patients were followed as to the composite coronary events, cardiac death, nonfatal myocardial infarction (MI), unstable angina requiring hospitalization (UAP), and late elective coronary revascularization ≥90 days after CT. According to the severity of stenosis, patients were categorized to normal (0% stenosis), non-obstructive (1-49% stenosis), and obstructive (≥50% stenosis) groups.
Results: During a 6.0 ± 2.8 years follow-up period, 48 composite coronary events were documented. The univariate hazard ratios (HR) for incidences of coronary events of the obstructive and non-obstructive CAD groups compared to the normal group were 4.51 (95%CI 2.37-9.16, P<0.001) and 1.51 (95%CI 0.71-3.30, P=0.28), respectively. In the receiver operative characteristics analysis, the cutoff point set at 100 mL/m2 provided the highest accuracy for coronary events. Kaplan-Meier curves demonstrated that high iEFV group (≥100 mL/m2) had a significantly lower event-free curve (HR 3.01, 95%CI 1.61-5.41, P=0.0009). Multivariate Cox-proportional hazard analysis revealed that coronary obstruction on CCTA (HR 3.04, 95%CI 1.64-5.59, P=0.0005) and high iEFV (HR 4.10, 95%CI 2.05-7.99, P=0.0001) remained as independent predictors. In subgroup analysis, the high iEFV was significantly associated in the non-obstructive group (HR 4.37, 95%CI 1.49-12.80, P=0.0083) (normal group; HR 1.63, 95%CI 0.25-6.19, P=0.5509, obstructive group: HR 2.50, 95%CI 0.94-6.00, P=0.064).
Conclusion: Our results from long-term follow-up study indicate that increased EFV is an independently predictive of future coronary events. This predictive power is enhanced in non-obstructive CAD patients.