Association of Initially Normal Coronary Arteries With Normal Findings on Follow-up Echocardiography in Patients With Kawasaki Disease.

IMPORTANCE American Heart Association guidelines recommend echocardiography in Kawasaki disease at baseline, 1 to 2 weeks, and 4 to 6 weeks after treatment to detect coronary artery abnormalities. However, these examinations are expensive and may require sedation in young children, which is burdensome and carries some risk. OBJECTIVE To assess the benefit of additional echocardiographic imaging at 6 weeks in patients with uncomplicated Kawasaki disease who had previously normal coronary arteries. DESIGN, SETTING, AND PARTICIPANTS This is a retrospective review of patients with Kawasaki disease who were cared for between 1995 and 2014 in 2 academic pediatric referral practices Eligibility criteria included receiving intravenous immunoglobulin treatment for acute Kawasaki disease at a center; the absence of significant congenital heart disease; available echocardiographic measurements of both the right and left anterior descending coronary arteries at 10 days or less after diagnosis (baseline), 2 (+/- 1) weeks, and 6 (+/- 3) weeks of illness; and normal coronary arteries at baseline and 2 weeks, defined as maximum coronary artery z scores less than 2.0 and no distal aneurysms. Data analysis was completed from March 2015 to November 2015. MAIN OUTCOMES AND MEASURES The number of patients with right coronary artery or left anterior descending coronary artery z scores of 2.0 or more at 6 weeks. RESULTS The median age of the 464 included patients was 3.3 years (interquartile range, 1.8-5.4 years); 264 (56.9%) were male, 351 of 414 for whom data were available (84.8%) had complete Kawasaki disease, and 66 (14.2%) received additional intravenous immunoglobulin treatment. At 6 weeks of illness, 456 patients (98.3%) who had had normal coronary artery z scores at baseline and 2 weeks continued to have normal z scores. Of the remaining 8 patients (1.7%), the maximum z score within 6 weeks was 2.0 to 2.4 in 5 patients (1.2%), 2.5 to 2.9 in 1 patient (0.2%), and 3.0 or more in 2 patients (0.4% [95% CI, 0.1%-1.5%]). Coronary artery dimensions ultimately normalized in all but 1 patient, who had minimal dilation at 6 weeks (right coronary artery z score, 2.1). Sensitivity analyses using less restrictive cut points (eg, a maximum z score <2.5) or less restrictive timing windows (eg, considering patients with incomplete echocardiographic data within 21 days) gave similar results; in these analyses, 454 to 463 of 464 patients (98% to 99.7%) had coronary artery z scores of less than 2.5 at 6 weeks. CONCLUSIONS AND RELEVANCE New abnormalities in coronary arteries are rarely detected at 6 weeks in patients with Kawasaki disease who have normal measurements at baseline and 2 weeks of illness, suggesting that the 6-week echocardiographic imaging may be unnecessary in patients with uncomplicated Kawasaki disease and z scores less than 2.0 in the first 2 weeks of illness.