Association between Femoral Artery Flow-Mediated Dilation and Muscle Oxygen Saturation Parameters in Healthy, Young Individuals

Flow-mediated dilation (FMD) and muscle oxygen saturation (StO(2)) are measurements utilized to assess macro- and microvascular function, respectively. Macro- and microvascular dysfunction may occur differently depending on the clinical condition. Since microvascular responsiveness can influence upstream conduit artery hemodynamics, the present study aimed to investigate whether a correlation between FMD and muscle StO(2) parameters exists. Sixteen healthy, young individuals were enrolled in this study. Femoral artery FMD and tibial anterior muscle StO(2) were evaluated by ultrasound and near-infrared spectroscopy, respectively. The FMD and muscle StO(2) parameters were assessed by employing a vascular occlusion test (VOT). The oxygen resaturation rate was determined by calculating the upslope of StO(2) immediately after occlusion and the magnitude of reperfusion as the difference between the highest and lowest StO(2) value achieved during the reperfusion phase. The oxygen desaturation rate and the magnitude of desaturation during the VOT were also evaluated. A significant correlation between the FMD and oxygen resaturation rate (r = 0.628; p = 0.009), magnitude of reperfusion (r = 0.568; p = 0.022), oxygen desaturation rate (r = −0.509; p = 0.044), and magnitude of desaturation (r = 0.644; p = 0.007) was observed. This study demonstrated a moderate association between the femoral artery FMD and tibial anterior StO(2) parameters in young individuals.