Validity of flow-mediated dilation and reactive hyperemia index in assessing the risk of coronary artery disease based on the new definition by the Japan Society for Vascular Failure

Abstract

Background: Flow-mediated dilation (FMD) measurement and reactive hyperemia-peripheral arterial tonometry (RH-PAT) are established methods for assessing vascular endothelial function. Recently, the Japan Society for Vascular Failure proposed a new definition for the values of FMD (≥7.0%, normal; 7.0%> and ≥4.0%, borderline; 4.0%≥, abnormal) and reactive hyperemia index (RHI) measured using RH-PAT (≥2.10, normal; 2.10≥ and >1.67, borderline; 1.67≥, abnormal). This study aimed to assess the clinical significance of FMD and RHI in coronary artery disease (CAD) based on the new definition. Methods: We performed simultaneous FMD and RH-PAT measurements in 131 patients undergoing coronary angiography for suspected CAD. The patients were divided into subgroups according to the normal, borderline, and abnormal values of FMD and RHI in the new definition. Results: No significant correlation was found between the FMD and RHI values in the overall patients. In the normal FMD/normal RHI, normal FMD/abnormal RHI, abnormal FMD/normal RHI, and abnormal FMD/abnormal RHI groups, the prevalence of multivessel CAD was 0%, 25%, 36%, and 56% (P=0.038), respectively. Furthermore, multivessel CAD was observed in 17% of patients in the borderline FMD/borderline RHI group, and the prevalence showed a significant difference among the normal FMD/normal RHI, borderline FMD/borderline RHI, and abnormal FMD/abnormal RHI groups (P=0.006). Multivariate logistic regression analysis showed that abnormal FMD/abnormal RHI was an independent predictor of multivessel CAD (odds ratio: 3.172, 95% confidence interval: 1.012-7.336, P=0.042). Conclusions: The evaluation of simultaneously measured FMD and RHI values based on the new definition would be advantageous for predicting the severity of CAD.