Development of a Pulmonary Artery Resistor (PAR) for treatment of infants with congenital heart disease characterized by excessive pulmonary blood flow and inadequate blood flow to the remainder of the body. Surgically-performed Pulmonary Artery Banding (PAB), in which a band is tightened around the pulmonary artery, is currently employed to properly balance the blood flow between the lungs and the body, until definitive surgical correction of the heart structure can be safely performed in a more mature infant. The PAR offers three advantages relative to current PAB practice, including 1) non-surgical, endovascular deployment in the pulmonary artery (PA), 2) subsequent endovascular adjustment of PA blood flow, and 3) avoidance of the permanent distortion of the PA present with PAQB. The proposed PAR will employ self-expansion for placement/anchoring in the PA, and balloon expansion for adjustment of the PA flow. CAD solid modeling, archived X-ray images of infant heart vasculature, and computational methods, including computational fluid dynamics (CFD) and finite element analysis (FEA), will be used to arrive at an optimum PAR design. PAR prototypes will be fabricated and evaluated on the bench and in a phantom, and will be made available to NHLBI personnel for evaluation.