Congenital heart disease (CHD) is a leading cause of pulmonary arterial hypertension (PAH) worldwide. Treatment for PAH associated with CHD (PAH-CHD) depends on the defect's type, size, and hemodynamic impact. For those with CHD correction indications, early defect repair or interventional closure is crucial to prevent irreversible pulmonary vascular remodeling due to prolonged exposure to a left-to-right shunt. Current guidelines recommend triple-combination therapy, including phosphodiesterase 5 inhibitors, endothelin receptor antagonist, and parenteral prostacyclin, for patients with intermediate-high or high risk. Recent studies suggest that patients with PAH-CHD and borderline hemodynamics might regain eligibility for surgery after targeted vasodilatory treatment. Consequently, early initiation of triple-combination therapy may be critical for severe PAH-CHD patients to restore their surgical or interventional closure eligibility. Therefore, we conducted this prospective study to assess the effectiveness of triple-combination therapy in severe PAH-CHD cases.