Association of Epicardial Adipose Tissue and High-Risk Plaque Characteristics: A Systematic Review and Meta-Analysis

Background-Epicardial adipose tissue (EAT) is hypothesized to alter atherosclerotic plaque composition, with potential development of high-risk plaque (HRP). EAT can be measured by volumetric assessment (EAT-v) or linear thickness (EAT-t). We performed a systematic review and random-effects meta-analysis to assess the association of EAT with HRP and whether this association is dependent on the measurement method used. Methods and Results-Electronic databases were systematically searched up to October 2016. Studies reporting HRP by computed tomography or intracoronary imaging and studies measuring EAT-v or EAT-t were included. Odds ratios were extracted from multivariable models reporting the association of EAT with HRP and described as pooled estimates with 95% confidence intervals (CIs). Analysis was stratified by EAT measurement method. Nine studies (n=3772 patients) were included with 7 measuring EAT-v and 2 measuring EAT-t. Increasing EAT was significantly associated with the presence of HRP (odds ratio: 1.26 [95% CI, 1.11-1.43]; P<0.001). Patients with HRP had higher EAT-v than those without (weighted mean difference: 28.3 mL [95% CI, 18.8-37.8 mL]; P<0.001). EAT-v was associated with HRP (odds ratio: 1.19 [95% CI, 1.06-1.33]; P<0.001); however, EAT-t was not (odds ratio: 3.09 [95% CI, 0.56-17]; P=0.2). Estimates remained significant when adjusted for small-study effect bias (odds ratio: 1.13 [95% CI, 1.03-1.28]; P=0.04). Conclusions-Increasing EAT is associated with the presence of HRP, and patients with HRP have higher quantified EAT-v. The association of EAT-v with HRP is significant compared with EAT-t; however, a larger scale study is still required, and further evaluation is needed to assess whether EAT may be a potential therapeutic target for novel pharmaceutical agents.