Introduction Based on data obtained before high-dose (2 g/kg) intravenous immunoglobulin (IVIG) therapy prevailed in Japan, children with a history of Kawasaki disease (KD) were highly susceptible to disease recurrence and more likely to develop cardiac sequelae. We aimed to examine the epidemiological features of cardiac complications among patients with recurrent KD following the widespread use of high-dose IVIG therapy.

Design Two cohorts of patients with recurrent KD retrieved from Japanese nationwide surveys (previous cohort: 1989–1994; recent cohort: 2003–2012) were compared.

Results Of 1842 patients with recurrent KD in the recent cohort, 3.5% and 5.2% developed cardiac sequelae at the initial and second episodes, respectively, which were markedly decreased compared with those (>10%, respectively) in the previous cohort. Multivariate analyses showed that the risk factors for cardiac sequelae at the second episode were similar between the cohorts. Patients with recurrent KD in both cohorts were more likely to have coronary aneurysms at the second episode than at the initial episode. However, when patients with coronary aneurysms at the initial episode were excluded from analyses, the difference in the proportions of coronary aneurysms between KD episodes disappeared in the recent cohort. Residual rates of previously formed coronary aneurysms were similar between the cohorts (approximately 50%).

Conclusion This study suggests that KD recurrence is no longer a risk factor for developing cardiac complications, unless cardiac sequelae appear at the initial episode. However, residual rates of previously formed coronary aneurysms remain high. Therefore, the importance of carefully managing coronary aneurysms associated with KD remains unchanged.