The impact of epicardial fat volume on coronary plaque vulnerability: insight from optical coherence tomography analysis

Aims Epicardial fat volume (EFV) has been implicated in coronary artery disease. Relationship between EFV and coronary plaque vulnerability has not been elucidated. The aim of this study was to investigate the association of EFV with coronary plaque vulnerability by using optical coherence tomography (OCT). Methods and results We enrolled 117 patients who underwent multislice computed tomography (MSCT) and OCT. EFV was quantified on MSCT. Patients were categorized according to tertiles of EFV: low tertile, EFV < 104.1 cm(3); mid-tertile, 104.1 cm(3) <= EFV <= 130.7 cm(3); high tertile, EFV > 130.7 cm(3). A total of 180 vessels and 221 plaques were assessed with OCT to detect a thin-capped fibroatheroma (TCFA). TCFA was defined as a plaque with necrotic lipid pools >= 2 quadrants and minimum fibrous cap thickness measuring < 65 mu m. Patients with low computed tomographic attenuation and positive remodelling were frequently observed and patients with OCT-derived TCFA were more common in the high tertile EFV. EFV was associated with a maximal lipid arc (103.4 +/- 28.2 cm(3) in 0 quadrant, 120.2 +/- 35.2 cm(3) in 1-2 quadrants, and 131.5 +/- 41.1 cm(3) in >2 quadrants; P = 0.01) and inversely correlated with a minimum fibrous cap thickness of the patients (r = -0.400, P < 0.01). In multivariate analysis, the high tertile of EFV remained an independent predictor for patients with OCT-derived TCFA [odds ratio (OR) 2.92; 95% confidence interval (CI) 1.13-7.55; P = 0.027] and acute coronary syndrome (ACS) patients (OR 2.89; 95% CI 1.14-7.29; P = 0.025). Conclusion EFV was associated with coronary plaque vulnerability and high EFV was an independent predictor of ACS in patients with coronary artery disease.