Epicardial adipose tissue thickness measured by echocardiography is associated with metabolic syndrome in a surgical cohort of patients with coronary artery disease and valvular heart disease
F Opdahl, T Toennessen, S Solheim, I G Lunde, S SaeedAbstract
Introduction
Epicardial adipose tissue (EAT) is a visceral fat depot that can be assessed by routine echocardiography and may reflect cardiometabolic risk beyond visceral adiposity. Metabolic syndrome (MetS) is associated with an increased risk of type 2 diabetes, cardiovascular disease and all-cause mortality. If EAT is associated with MetS, echocardiography could offer an opportunity to identify high-risk patients during standard cardiac assessment, especially those who are scheduled for cardiac surgery.
Purpose
We aimed to assess whether echocardiographic EAT thickness was associated with MetS in a surgical cohort of coronary artery disease (CAD) and valvular heart disease (VHD) patients. Furthermore, we wanted to assess the correlation of waist-to-height ratio (WHtR) and body mass index (BMI) with EAT and pericardial adipose tissue (PAT) thickness.
Methods
74 patients (median age 67, 69% male) with CAD (n=52) or VHD (n=22) undergoing open heart surgery were included between 2016-2018. Medical records were reviewed for all-cause mortality. Median follow-up time was 8.9 years. All echocardiograms were retrospectively analyzed. EAT thickness was measured on preoperative echocardiography (parasternal short or long-axis views) by an experienced cardiologist. EAT was defined as the hypoechoic space between the myocardium and the visceral pericardium and measured in end-diastole. PAT was measured as the hypoechoic space above the fibrous pericardium. MetS was defined by the presence of at least three of the following: waist circumference ≥102 cm for men and ≥88 cm for women, triglycerides ≥1.7 mmol/L, HDL <1.0 mmol/L for men and <1.3 mmol/L for women, systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥85 mmHg, and fasting glucose ≥5,6 mmol/L. Use of medication for triglycerides, HDL, blood pressure or glucose was considered as fulfilling that criterion.
Results
The mean EAT thickness was 4.1 mm and the mean PAT thickness was 6.5 mm, with no significant differences between patients with CAD vs. VHD. Patients with MetS (56%) had more EAT vs. those without (4.4 vs. 3.1 mm, p=0.001) (Figure A). Each 1 mm higher EAT was associated with higher odds ratio of MetS (OR 1.96, 95% CI 1.3–3.4; p=0.006). EAT thickness correlated with BMI and waist-to-height ratio (WHtR) (Figure B, C). In a univariate Cox regression analysis, EAT was not associated with all-cause mortality (HR 1.02, 95% CI 0.77-1.4). PAT correlated only with BMI (r = 0.25, p = 0.033) and was not associated with MetS.
Conclusion
EAT measured by echocardiography was associated with a nearly two-fold higher odds of MetS in a surgical cohort of CAD and VHD patients, supporting its potential as an echocardiographic marker of cardiometabolic risk. WHtR was associated with EAT thickness, reinforcing its value as a surrogate measure of visceral adiposity. Further studies are warranted to correlate these findings with mRNA expression of inflammatory molecules in EAT and PAT.EAT by MetS and correlation to WHtR and BMI