Untreated Kawasaki Disease (KD) can lead to coronary artery (CA) dilations, such as CA aneurysms (CAA), CA ectasia (CAE), or both (CAA + CAE). Currently, therapeutic decisions rely solely on geometric measurements, which have limitations. This study aims to correlate differences in flow dynamics between CAA, CAE, and CAA + CAE with clinical outcomes and thrombotic potential.