Baseline coronary artery dilation at diagnosis and age younger than 6 months were consistent predictors of coronary artery aneurysm at 1 month after Kawasaki disease onset in both large Japanese and US cohorts.
Baseline coronary artery dilation at diagnosis was strongly associated with coronary artery aneurysm 1 month after disease onset in both cohorts.
Age younger than 6 months was independently associated with increased risk of coronary artery aneurysm in both cohorts.
Intravenous immunoglobulin (IVIG) resistance was independently associated with increased risk of coronary artery aneurysm.
The study included a large combined sample of 43,566 children with Kawasaki disease from Japan and the United States.
The identified risk factors were relevant not only for any coronary artery aneurysm but also for medium to giant coronary artery aneurysms specifically.
Early coronary artery assessment at the time of Kawasaki disease diagnosis provides important prognostic information for cardiovascular risk stratification.
Kawasaki disease is an inflammatory condition that primarily affects young children and can cause serious damage to the coronary arteries — the blood vessels that supply the heart. The most feared complication is the formation of coronary artery aneurysms (CAAs), which are abnormal bulges in these vessels that can lead to heart attacks or other long-term heart problems. This large study, involving over 43,000 children from Japan and the United States, examined which early warning signs best predict which children will develop CAAs about one month after their illness begins. This research suggests that three key factors at the time of diagnosis are strongly linked to later development of CAAs: (1) already having some enlargement of the coronary arteries when first diagnosed, (2) being younger than 6 months of age, and (3) not responding to the standard treatment — intravenous immunoglobulin (IVIG). The strongest predictor was coronary artery dilation already present at diagnosis, which increased the odds of developing a CAA roughly 13 to 23 times depending on the population studied. Importantly, children who did not respond to IVIG treatment were at particularly elevated risk even if their coronary arteries looked normal at the time of diagnosis, highlighting that treatment response is a critical piece of prognostic information. These findings matter because they were consistent across two very different populations — Japanese and multiethnic American children — and also applied to the most serious, large aneurysms. This research suggests that performing an echocardiogram (heart ultrasound) early in the course of Kawasaki disease and closely monitoring how children respond to initial treatment could help doctors identify which patients need more aggressive follow-up and management to prevent serious heart complications.
Yamazaki S, Miyata K, Sun X, Shimizu C, Ae R, Dummer K, et al.. (2026). Risk Factors for Coronary Artery Aneurysms in Children With Kawasaki Disease.. Journal of the American Heart Association. https://doi.org/10.1161/JAHA.126.050238