UC San Diego

Kawasaki Disease (KD) is the leading cause of acquired heart disease in children and can result in life- threatening coronary artery aneurysms in up to 25% of patients. These aneurysms put patients at risk of thrombus formation, myocardial infarction and sudden death. Clinicians must therefore decide which patients should be treated with anticoagulant medication and/or surgical and percutaneous intervention. Current recommendations regarding initiation of anticoagulant therapy are based on anatomy alone with historical data suggesting that patients with aneurysms ≥ 8mm in diameter are at highest risk of thrombosis. Given the multitude of variables that influence thrombus formation, we postulate that hemodynamic data derived from patient-specific blood flow simulations will better predict the risk of thrombosis than maximum diameter alone. Firstly, a finite element framework with a lumped parameter boundary condition was implemented following a circuit analogy. A patient-specific case study was carried out to study the abnormalities in hemodynamics arising due to the presence of the aneurysms in the coronary arteries. Furthermore, simulations were performed on a virtual normal control model created from the same CT image data to demonstrate order of magnitude variation of several local hemodynamic quantities despite no differences in global flow and pressure waveforms between the two models. Secondly, blood flow simulations were performed on patient-specific models on a cohort of KD patients with coronary aneurysms and one KD patient with no coronary aneurysms. Key hemodynamic quantities including shear stress and residence times were computed in addition to geometric parameters and compared to the corresponding values in the normal vessels with no aneurysms. The findings uncovered various non-intuitive relationships between the flow parameters and geometry relating to the risk of thrombosis. The study suggested that a clinical risk index based on simulation and geometric data could be used to select patients for anticoagulant therapy. To our knowledge, we performed the first cardiovascular simulations for KD patients with coronary aneurysms. This thesis lays the framework for the construction of a simulation based clinical risk index by considering a larger cohort of patient data that may be clinically useful in patient management for KD patients with coronary aneurysms