Case of Anticoagulation Treatment With New-Generation Medications in Kawasaki Disease With Giant Coronary Aneurysms in Children

Introduction Kawasaki disease (KD) is an acute inflammatory disorder, with coronary artery aneurysms (CAAs) as a serious complication [1]. When giant CAAs develop, standard anticoagulation regime is low molecular weight heparin (LMWH) with low doses of aspirin [2] [3]. This case highlights the limitations of LMWH and explores benefits of newer anticoagulation therapies. Case Presentation A 5 month old boy with a recent history of upper respiratory tract infection presented to LSMUL Kaunas Clinics with persistent fever for 7 days, conjunctival infection and skin rash. Echocardiography showed multiple CAAs: medium size in the left main coronary artery (Z score: 7.28) and giant aneurysm (GA) in right coronary artery (Z score: 10.67). Thrombocytosis was noted. He was diagnosed with incomplete KD and coronary involvement. Hence started on intravenous immunoglobulin (IVIG) (2mg/kg), oral prednisolone (2mg/kg) and high dose aspirin therapy with LMWH. However, LMWH injections were stressful for the parents and the patient. Rising thrombocyte count and persistent GAs led to intensifying anticoagulation by adding clopidogrel (2mg/d) and switching LMWH to rivaroxaban (2.5mg 3x/d). This combination was well tolerated during 6 months of follow up. Discussion KD primarily affects children under 5y, with annual incidence of 10-15 per 100,000 children in Europe [4] and 3-5 cases per year in Lithuania [5]. This idiopathic vasculitis targets mainly coronary arteries, potentially leading to aneurysms. Prompt anti-inflammatory treatment with IVIG and aspirin reduces CAA risk, however, in GA cases, anticoagulation is essential. The need for subcutaneous injections twice daily for LMWH and constant INR monitoring with bleeding risks for Warfarin pose challenges in pediatric patients. Direct oral anticoagulants (DOACs) like rivaroxaban offer a practical alternative, reducing thrombosis risk and improving quality of life. Recent studies show DOACs prevent thromboembolic events in KD [6], suggesting a shift in anticoagulation therapy for children with CAAs. Conclusions This case highlights the potential of new anticoagulation strategies in KD patients with GAs. While studies focus on long-term use in older populations [7], our findings suggest effectiveness in pediatrics. Rivaroxaban and clopidogrel successfully managed platelet activation, showed favourable outcomes.