The utility of 4D flow MRI and computational fluid dynamics in developing the fontan model enhances presurgical planning and ensures better outcomes: the first case report in Thailand.

The Fontan procedure is a surgical palliation for patients with single-ventricle congenital heart defects. Optimal hemodynamic planning is required to minimize energy loss and systemic venous pressure. This study integrated four-dimensional (4D) flow magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) to evaluate three Fontan connection configurations in a twelve-year-old patient, aiming to identify the optimal design for presurgical planning. Model 2, which involved an extracardiac conduit anastomosed to the pulmonary artery with the main pulmonary artery stump excised, demonstrated the lowest power loss (8.1 mW), stable venous pressures (< 16 mmHg), and balanced pulmonary perfusion. This model was selected for surgery, and postoperative imaging confirmed successful anatomical reconstruction, preserved single-ventricle function (ejection fraction: 55%), and a well-balanced pulmonary flow distribution with LPA: RPA flow ratio of 38.9%:61.1%. Follow-up magnetic resonance lymphangiography at one and six months postoperatively showed a reduction in systemic venous congestion, decreased periportal lymphatic stasis, and no major complications such as chylothorax or ascites. These findings underscore the potential of CFD-based presurgical planning in improving Fontan outcomes by minimizing hemodynamic inefficiencies and postoperative complications. This study highlights the role of computational modeling in refining surgical strategies, ultimately enhancing patient outcomes and long-term quality of life in patients with Fontan physiology.