Abstract
BACKGROUND: Data on the use of rivaroxaban in children with giant coronary artery aneurysm (GCAA) after Kawasaki disease (KD) remain limited. OBJECTIVES: This study evaluated the feasibility of rivaroxaban in Chinese children with GCAA after KD. METHODS: This study was conducted at the Children's Hospital of Fudan University. Children aged 1 month to 18 years with persistent GCAA (diameter ≥ 8 mm or Z-score ≥ 10) during the postacute period of KD were included and followed up for at least 6 months. The study consisted of 2 stages. During the first stage (January-December 2023), patients received rivaroxaban following the 20-mg-equivalent regimen. In the second stage (January-November 2024), a pharmacometric model-informed rivaroxaban regimen was implemented. The primary outcome was a composite of GCAA thrombosis and major adverse cardiovascular event within 6 months. The secondary outcome included major bleeding and clinically relevant nonmajor (CRNM) bleeding. RESULTS: In the first stage, 6 patients were enrolled (median age, 14.6 months; range, 4.7-130.8 months; median weight, 9.9; range, 6.6-33 kg; Z-score, 14.9; range, 10.6-28.0). No primary outcome or major bleeding occurred. Four CRNM bleedings were documented, leading to 6 dose adjustments. Two patients discontinued rivaroxaban due to improved coronary status. In the second stage, 14 patients received the 15-mg-equivalent rivaroxaban regimen (median age, 69.7 months; range, 16.4-143.1 months; median weight, 19.5 kg; range, 12.5-57.5 kg; Z-score, 14.7; range, 10.6-39.1). No primary or secondary outcome occurred. Two patient important bleeding no intervention events were documented. All patients remained on rivaroxaban beyond 6 months. External validation supported the predictive performance of model extrapolation. CONCLUSION: The 15-mg-equivalent rivaroxaban regimen appeared feasible in Chinese children with GCAA after KD, with no GCAA thrombosis, major bleeding or CRNM bleeding observed within 6 months. Larger studies are required to confirm these preliminary findings.