Background: Endothelial dysfunction and increased left ventricular (LV) stiffness are associated with the incidence of heart failure with preserved ejection fraction (HFpEF). This study evaluated the association between endothelial dysfunction and LV diastolic stiffness.Methods and Results: Endothelial dysfunction evaluated by flow-medicated vasodilation (FMD) and the reactive hyperemia index (RHI), which reflects endothelial dysfunction in the microvasculature, was measured in 112 subjects with hypertension in the Flow-Mediated Dilation Japan (FMD-J) study. Using transthoracic echocardiography, LV diastolic stiffness was evaluated by measuring diastolic wall strain (DWS) in the LV posterior wall. In this cross-sectional study, associations among FMD, RHI, and DWS were investigated using multiple regression analyses. The mean (±SD) age of the subjects 65±9 years, and 63% were men. DWS was significantly associated with RHI, but not FMD, on multivariate linear regression analysis (β=0.39; P<0.0001). This association was preserved in subjects without LV hypertrophy (β=0.46; P<0.0001). A DWS ≤median, suggesting increased LV diastolic stiffness, was significantly associated with RHI on multivariate logistic regression analysis (odds ratio 20.58; 95% confidence interval 4.83-87.63; P<0.0001). The receiver operating characteristic curve presented a cut-off value of 2.21 for RHI, with a sensitivity of 77% and a specificity of 71%, for DWS ≤median.
Conclusions: RHI, rather than FMD, was associated with DWS. Endothelial dysfunction in the microvasculature may be associated with increased LV diastolic stiffness.
Keywords: Diastolic wall strain; Endothelial dysfunction; Left ventricular stiffness; Reactive hyperemia index.