Coronary artery dimensions may be misclassified as normal in Kawasaki disease

Background: Current American Heart Association guidelines indicate that patients with Kawasaki disease and no coronary artery abnormalities on echocardiography at any stage of illness may be discharged from cardiologic follow-up 1 year after onset of illness. Methods and Results: To determine whether coronary artery dimensions in patients with Kawasaki disease whose vessels are classified as "normal" by Japanese Ministry of Health criteria have a distribution similar to expected population norms when adjusting for body surface area, we studied 125 patients during 4 intervals from onset of illness: (1) 10 days or less, (2) 2 weeks (11 to 21 days), (3) 6 weeks (22 days to 3 months), and (4) 1 year (4 months to 1.5 years). Using two-dimensional echocardiography, we measured the internal lumen diameter of the left main, proximal left anterior descending, and proximal right coronary arteries. Mean body surface area-adjusted dimensions of the proximal left anterior descending and right coronary arteries were significantly larger (P < .01) in patients with Kawasaki disease than those in subjects in all periods, except for a marginal difference at 6 weeks for the proximal right coronary artery (P = .02); for the left main coronary artery this difference achieved statistical significance in the period of 10 days or less, with a trend at 2 weeks (P = .02). Among patients classified as having normal coronary arteries on all echocardiograms by the Japanese Ministry of Health criteria, 27% had at least 1 body surface area-adjusted coronary dimension more than 2 standard deviations above the expected mean. Conclusions: Coronary artery dilation in Kawasaki disease is thus more prevalent than previously reported, highlighting the need for systematic long-term surveillance of this population.