*5.2.1 Percentage change in flow-mediated dilatation: %FMD*

Percentage change in flow-mediated dilatation (%FMD) reflects endothelial nitric oxide-dependent vasodilatation. A significant decrease in %FMD is a common feature of atherosclerosis in adults. Some meta-analyses reported that %FMD was lower in the KD group than in the control group, indicating endothelial damage and a risk of atherosclerosis [27–29]. Several previous studies have reported that the %FMD was significantly lower in patients with a history of KD than in control subjects, showing systemic endothelial dysfunction late after KD onset [30–32]. Interestingly, in pediatric patients with CAL late after KD, there is increased high-sensitivity C-reactive protein in addition to reduced %FMD, indicating the presence of ongoing chronic vascular inflammation and endothelial dysfunction [31].
