[Correlation between epicardial adipose tissue thickness and slow flow of non-obstructive coronary artery]

Objective: To investigate the correlation between epicardial adipose thickness and slow flow of non-obstructive coronary artery. Methods: Clinical data of patients with coronary angiography examination evidenced stenosis<50% in our department from May 2014 to May 2015 were retrospectively analyzed.According to the level of TIMI in angiography, patients were divided into slow blood flow group (TIMI Ⅰ-Ⅱ, n=16) and normal blood flow group (TIMI Ⅲ, n=127). All epicardial adipose thickness was determined by echocardiography and data of biochemical data (fibrinogen, whole blood viscosity at high shear rate, erythrocyte aggregation index, platelet count, and platelet aggregation rate) were also analyzed.Multivariate logistic regression analysis was used to identify whether epicardial adipose thickness was a risk factor for the occurrence of slow flow of non-obstructive coronary artery.A linear regression analysis was used to identify the correlation between epicardial adipose thickness and severity of slow flow of non-obstructive coronary artery.Receiver operating characteristic (ROC) curve was used to analyze the predicting value of epicardial adipose thickness on slow flow of non-obstructive coronary artery. Results: The epicardial adipose thickness was significantly thicker in slow blood flow group than in normal blood flow group ((8.18±2.25) mm vs. (4.65±0.88) mm, P<0.01). The plasma fibrinogen concentration((4.17±1.13) g/L vs.(2.29±0.92) g/L, P<0.01), erythrocyte aggregation index (7.88±1.07 vs. 5.46±1.17, P<0.01), platelet count ((274.1±8.6)×10⁹/L vs.(215.3±72.3)×10⁹/L, P<0.01) and platelet aggregation rate ((0.81±0.11)% vs.(0.64±0.12)%, P<0.01) were significantly higher in slow blood flow group than in normal blood flow group.Whole blood viscosity at high shear rate was similar between the two groups ((4.16±0.56) mPa·s vs.(3.88±0.51) mPa·s, P>0.05). Multivariate logistic regression analysis showed that epicardial adipose thickness was a risk factor for slow flow of non-obstructive coronary artery(OR: 6.813, 95%CI 1.130-41.074, P<0.05). Linear regression analysis showed that there was a negative association between epicardial adipose thickness and TIMI level of non-obstructive coronary artery (R=0.802, R²=0.644, B=-0.237, P<0.01). ROC analysis showed that the accuracy of prediction of epicardial adipose thickness on coronary artery slow flow was high(area under the curve was 0.941, 95%CI 0.876-1.000, P<0.01). When the thickness reached 6.1 mm, the prediction index was maximum (0.766), and the sensitivity was 0.813, and the specificity was 0.953. Conclusion: Epicardial adipose thickness is related to slow flow of non-obstructive coronary artery and epicardial adipose thickness can be used as a predictor for slow flow of non-obstructive coronary artery.