Background Kawasaki disease (KD) is a medium vessel vasculitis occurring in children, as yet of undetermined aetiology. KD can lead to severe complications such as coronary artery aneurysms, thrombosis, and sudden death. Monitoring of coronary anomalies is an important issue in the early phase of the disease, and their follow-up is based on different imaging methods. The interventional treatment of these coronary anomalies, which is often complex, is a therapeutic challenge. Case summary We are reporting the case of a four-year-old child who presented KD which was complicated by coronary aneurysm of the proximal left anterior descending artery and ectasia of the right coronary artery (RCA). These lesions progressively calcified and resulted at the age of 13 in chronic occlusion of the RCA. After confirmation of myocardial viability and myocardial ischaemia, a complex angioplasty guided by intracoronary imaging was performed using rotational atherectomy, a cutting balloon, and a high pressure balloon. The control coronary angiography performed 1 year later revealed two false aneurysm on the RCA at the angioplasty site, which were successfully treated with a covered stent. Discussion This case report describes the challenges of treating coronary artery abnormalities such as calcified coronary lesions in children with KD. The coronary intervention of these lesions remains complex and may lead to coronary rupture. We highlight the advantage of using intracoronary imaging in the management of these calcified lesions for successful revascularization, and to assess the complications of percutaneous coronary intervention.