Prognostic value of coronary artery calcium and epicardial adipose tissue assessed by non-contrast cardiac computed tomography.

OBJECTIVE: Epicardial adipose tissue (EAT) accumulation is believed to be associated with development of coronary atherosclerosis. We investigated whether EAT volume as assessed by computed tomography (CT) has value in prediction of future cardiac events.

METHODS: We studied 722 patients without proven coronary artery disease (CAD) who underwent non-contrast cardiac CT. EAT volume and coronary artery calcium (CAC) score were measured simultaneously. Patients were followed as to the occurrence of coronary events (cardiac death, nonfatal myocardial infarction, unstable angina requiring hospitalization, and late coronary revascularization≥3 months after CT examination).

RESULTS: During a 3.7±1.7 years follow-up period, 37 coronary events were documented. Annual event rates increased across CAC score categories (0.3%, 1.0%, 2.4%, and 4.3%, in 0, 1-99, 100-399, and ≥400, respectively, p<0.001); these were significantly higher in the higher EAT volume group (>median; 107.2 mL, 0.7% vs., 2.1%, adjusted hazard ratio; 2.65, p=0.0090). Cox-proportional hazard analysis demonstrated that a combination of CAC score≥100 and high EAT volume had a significantly higher event rate than CAC score<100 and low EAT volume group (adjusted hazard ratio 11.6, p<0.0001). Using Cox regression models, incremental prognostic values were identified by adding high EAT volume to clinical risks plus CAC score≥100 (global χ2, 6.7; p=0.059).

CONCLUSION: We suggest that high EAT volume may be an independent predictor of future coronary events and increases predictive values of CAC score in patients without proven CAD.