Coronary Artery Involvement in Kawasaki Disease and Multisystem Inflammatory Syndrome in Children: Imaging, Risk Stratification, and Long-Term Cardiovascular Considerations

Kawasaki disease (KD) and multisystem inflammatory syndrome in children (MIS-C) are pediatric inflammatory conditions with significant cardiovascular involvement, particularly affecting the coronary arteries. KD remains the leading cause of acquired heart disease in children worldwide, while MIS-C has emerged as a postinfectious complication of severe acute respiratory syndrome coronavirus 2 with overlapping but distinct cardiovascular manifestations. Coronary artery abnormalities, including dilation and aneurysm formation, represent the most important cardiovascular sequelae in KD, whereas coronary involvement in MIS-C appears less frequent and often transient, although its long-term implications remain incompletely understood. Early detection and longitudinal assessment of coronary involvement are essential for optimizing outcomes. Echocardiography is the first-line imaging modality for both KD and MIS-C due to its accessibility and high sensitivity in detecting proximal coronary abnormalities. However, advanced imaging techniques such as coronary computed tomography angiography and cardiac magnetic resonance imaging provide superior visualization of distal coronary segments, vessel wall characteristics, myocardial perfusion, and fibrosis. These modalities are increasingly integrated into follow-up strategies, especially in patients with complex or persistent lesions. Risk stratification is guided by coronary artery Z scores, inflammatory biomarkers, and clinical severity, enabling tailored therapeutic approaches, including antiplatelet and anticoagulation therapy. Despite advances in treatment, a subset of patients with KD develops persistent coronary artery abnormalities with potential progression to ischemic heart disease later in life. In contrast, current evidence suggests that most cardiovascular abnormalities in MIS-C improve over time, although long-term longitudinal data remain limited. This review synthesizes current evidence on the pathophysiology, imaging strategies, risk assessment, and long-term cardiovascular outcomes in KD and MIS-C. A multimodal imaging approach combined with individualized risk stratification is essential for improving prognosis and guiding lifelong surveillance in affected patients.