Previous studies in patients with a history of Kawasaki disease (KD) have focused on the endothelial function of
the coronary arteries and that of the systemic arteries is not fully understood. Furthermore, the effect of vitamin
C on systemic vascular endothelial function after KD has not yet been elucidated. In the present study, 39
patients (age, 7.1±2.7 years) at 1–10 years after acute KD were compared with 17 matched healthy subjects
(7.0±3.1 years). High-resolution ultrasonography was used to analyze brachial artery responses to reactive
hyperemia (with increased flow causing endothelium-dependent dilation) and sublingual nitroglycerin (causing
endothelium-independent dilation) after KD, and to investigate whether the acute administration of vitamin C
can restore systemic endothelial dysfunction. The percent change in diameter of the brachial artery induced by
reactive hyperemia in the patients with a history of KD (6.2±3.9%) was significantly less than that in the control
group (14.1±6.8%, p<0.0001). No significant difference could be found in the percent change in diameter
induced by sublingual nitroglycerin between the controls (33.2±13.7%) and the patients (30.6±9.2%, p=0.49).
There was no significant difference in percent change in diameter of the brachial artery induced by reactive
hyperemia between the patients who received gamma globulin (6.0±4.0) and those who did not (7.9±3.3,
p=0.33). Intravenous infusion of vitamin C significantly increased the percent change in diameter of the brachial
artery induced by reactive hyperemia in 19 patients with history of KD (6.6±3.5% to 13.0±5.5%, p<0.0001).
After placebo administration in 20 patients with history of KD there was no significant increase in the percent
change in the diameter of the brachial artery induced by reactive hyperemia (6.5±4.5% to 7.3±4.9%, p=0.20).
The decreased percent change in the diameter of the brachial artery induced by reactive hyperemia in patients
with a history of KD compared with the healthy children indicates that systemic endothelial dysfunction exists
after KD. Although it is not influenced by early treatment with high-dose gamma globulin in the acute stage of
KD, systemic vascular endothelial function can be restored by acute intravenous administration of vitamin C.
