Cardiac sequelae of Kawasaki disease are an important cause of ischemic heart disease in young adults. The possibility of early progression of atherosclerosis following Kawasaki disease is therefore of great concern. We examined whether preclinical atherosclerotic changes are seen in patients with a history of Kawasaki disease, and whether these changes appear in all or in only a proportion of patients. Sixty-five patients with a history of Kawasaki disease, aged 13.1 +/- 2.1 years, and 20 aged-matched controls participated in the study. All subjects underwent flow-mediated dilatation (FMD) of the brachial artery and analysis of carotid artery size and pulse-wave transmission. Patients were classified into four groups depending on the severity of the maximum coronary artery lesion: group 0 (normal), group 1 (mild), group 2 (moderate), and group 3 (severe). There was no statistical difference in the carotid artery analyses between the four groups. FMD (mean +/- SD) was significantly lower in groups 2 and 3 than in groups 0 and 1 and the control group (group 0, 19.4 +/- 3.9%; group 1, 19.5 +/-4.1%; group 2, 8.9 +/- 2.8%; group 3, 4.2 +/- 1.5%; control group, 18.8 +/- 2.8%; p < 0.0001). There was a significantly negative correlation between the severity of the coronary artery lesion and FMD (p < 0.0001 for both). Endothelial dysfunction was revealed by FMD in patients with persistent coronary artery lesions subsequent to Kawasaki disease. Preclinical atherosclerosis may be present only in patients with coronary aneurysms.