Follow-Up Duration of Echocardiography in Patients with Kawasaki Disease with No Initial Coronary Aneurysms

To evaluate the optimal duration of echocardiographic follow-up in patients with Kawasaki disease without an initial coronary aneurysm.In this single-center, retrospective, observational study, we reviewed the results of follow-up echocardiography in children with Kawasaki disease enrolled in the Prospective Observational Study on Stratified Treatment with Immunoglobulin Plus Steroid Efficacy for Kawasaki Disease from a children's hospital. The main enrollment criterion was the absence of coronary aneurysms, defined as a maximum z-score (Zmax) ≥2.5, in the proximal right coronary artery and the proximal left anterior descending artery within 9 days from treatment initiation. The primary outcome was Zmax on follow-up echocardiography at up to 5 years.Among 386 patients, 106 (27.5%) received prednisolone with intravenous immunoglobulin for first-line therapy, and 57 (14.8%) showed a poor response. Echocardiography at 1 month detected 9 patients with a Zmax ≥2, including 3 (0.8%) with coronary aneurysms requiring additional antithrombotic treatment and observation. Of 7 patients (1.8%) with normal echocardiographic findings at 1 month but a Zmax ≥2 later, 2 were lost to follow-up and 5 experienced spontaneous resolution, but none of the 7 patients required any change in management.The optimal duration of echocardiographic follow-up may be 1 month in patients with no initial coronary aneurysms and a Zmax <2 at 1 month. Coronary artery abnormalities observed after 1 month are rare and mostly benign in this category of patients.