Clinical outcomes of rivaroxaban and warfarin for anticoagulation in children with giant coronary artery aneurysms after Kawasaki disease

Children with giant coronary artery aneurysms (gCAA) after Kawasaki disease (KD) are at high risk of coronary artery thrombosis (CAT), associated with adverse cardiovascular events (ACEs). Long-term anticoagulation is the standard regimen, but evidence comparing rivaroxaban with warfarin in gCAA after KD remains limited. We performed a retrospective observational study at 2 pediatric centers from 2020 to 2025, enrolling children with gCAA after KD. Participants received rivaroxaban or warfarin. The primary efficacy assessment included ACEs and CAT outcomes within 6 months. CAA changes and safety outcomes were assessed. The final cohort included 30 patients, 14 treated with rivaroxaban and 16 with warfarin. ACEs were infrequent, occurring in 1 patient (7.1%) receiving rivaroxaban and 2 patients (12.5%) receiving warfarin. Among patients without CAT at baseline, new-onset CAT occurred in 1 of 10 patients (10.0%) receiving rivaroxaban and 1 of 12 patients (8.3%) receiving warfarin. Among patients with CAT at baseline, CAT resolved in 2 of 4 patients in each group. CAA progression was observed in 7 patients (50.0%) in the rivaroxaban group and 10 patients (62.5%) in the warfarin group, whereas CAA regression occurred in 6 patients (42.9%) and 5 patients (31.2%), respectively. No major bleeding or prespecified severe hypersensitivity events were observed in either group. Over the 6-month follow-up, ACEs, CAT outcomes, CAA changes, and safety outcomes were descriptively similar among children receiving rivaroxaban or warfarin. These descriptive findings require confirmation in larger prospective studies.