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.