Flow-Mediated Dilation, a Marker of Endothelial Cell Dysfunction, in Patients with Pulmonary Hypertension.

Background: Flow-mediated dilation (FMD) is considered a marker of endothelial cell dysfunction (ECD) and has been mostly evaluated in coronary artery disease. The role of ECD in the pathogenesis of pulmonary hypertension (PH) is not well-known. This study sought to evaluate the relationship between FMD and PH. Materials and Methods: In this cross-sectional study, the FMD of the brachial artery was measured in 40 confirmed PH patients. Meanwhile, echocardiographic findings, the 6-minute walk test (6MWT), and serum pro-brain natriuretic peptide (pro-BNP) level were evaluated. Overall, 20 patients accomplished all evaluations, and their data were analyzed using SPSS software (version 23). Results: There was an inverse relationship between pro-BNP and 6MWT (r<0, P<0.05). A significant direct relationship was observed between left ventricular ejection fraction and FMD (P=0.031). Right ventricular (RV) dilation was significantly correlated with pro-BNP (P=0.046). There was a significant direct correlation between RV function and FMD and a significant inverse relationship between pro-BNP and FMD (P=0.05). The independent t-test showed no relationship between FMD and syncope (P=0.75). Conclusion: Endothelial cell function, which can be evaluated by FMD, was involved in patients with PH. The FMD and 6MWT were helpful as objective prognostic markers in PH. Furthermore, pro-BNP was a noninvasive indicator in the diagnosis of RV systolic dysfunction.