Measurement of epicardial fat thickness by transthoracic echocardiography for predicting high-risk coronary artery plaques.
Level 3 - non-randomized controlled study
Cross-sectional diagnostic and observational study comparing echocardiographic measurements against coronary CT angiography.
PubMed 26833041 · doi:10.1007/s00380-016-0802-5
What was done
Evaluated 406 patients (mean age 63 years, 57% male) referred for 64-slice coronary computed tomography (CT) angiography. Epicardial adipose tissue (EAT) thickness was measured via transthoracic echocardiography on the right ventricular free wall from the parasternal long-axis view at end-systole. High-risk coronary plaques were defined on CT as low-density plaques (<30 Hounsfield units) exhibiting positive remodeling (remodeling index >1.05). Patients were categorized into thin or thick EAT groups based on a receiver operating characteristic (ROC) cutoff, and associations were evaluated using multivariable logistic regression adjusting for conventional risk factors, visceral adipose area, and medications.
What was found
The ROC cutoff for EAT thickness was 5.8 mm (AUC 0.77, 95% CI 0.70–0.83, p < 0.01; sensitivity 83%, specificity 64%). Compared to the thin EAT group, patients with thick EAT had significantly higher rates of low-density plaques (24% vs. 4%, p < 0.01), positive remodeling (60% vs. 39%, p < 0.01), and high-risk plaques (17% vs. 3%, p < 0.01). On multivariable logistic regression, thick EAT independently predicted high-risk plaques (OR 7.98, 95% CI 2.77–22.98, p < 0.01).
Why it matters
Echocardiographic EAT thickness is a low-cost, radiation-free measurement that may help identify patients harboring vulnerable, high-risk coronary plaques.
Limits
The study used a cross-sectional design in a single referral cohort undergoing CT angiography, introducing potential referral bias. Specificity of the 5.8 mm cutoff was relatively low (64%), and the wide confidence interval for the odds ratio (2.77–22.98) reflects imprecision. Single-point right ventricular thickness measurement may not capture total volumetric epicardial fat distribution, and long-term hard clinical cardiovascular events were not evaluated.
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- supports An echocardiogram does not effectively visualize arterial plaque.