PROJECT SUMMARY/ABSTRACT Congenital heart defects (CHDs) occurs in ~1% of births in the U.S. and Europe. Owing to improved medical and surgical care, it is estimated that nowadays 83% of babies born with CHD in the U.S. survive infancy. Presently, it is estimated that at least 1 million children are living with CHD in the U.S. Most of these patients are born with some degree of right ventricular outflow tract (RVOT) abnormalities that at some point require pulmonary valve replacement to mitigate the detrimental effects of pulmonary valve regurgitation (PVR) on the right ventricle (RV). The RVOT obstruction often needs to be surgically relieved within the first few months of life. The surgery to relieve RVOT obstruction usually involves placing a transannular patch, which results in PVR that can lead to progressive RV dilation over time, and ultimately RV failure. Although progressive PVR must be addressed at a younger age, in patients who are as small as 10 Kg, the smallest available pulmonary heart valve can only be implanted in a child whose weight is at least 20 Kg. To address this unmet clinical need, we aim to develop, implant, and study the performance of a novel origami-based transcatheter pulmonary valve (TPV) system that can be implanted in a child as small as 8 Kg and accommodates the child's growth through a one-time balloon expansion. The proposed novel technology aims to address the current lack of options for children with progressive PVR whose weight is between 8 and 20 Kg, and will stop progressive RV dilation and ultimately avoid the occurrence of RV failure in these children. The overarching hypothesis of this exploratory application is that a growth- accommodating TPV developed based on origami concepts can be implanted in minipigs as small as 8-10 Kg, and through one-time balloon expansion it can be augmented to be suitable for minipigs weighing 20-22 Kg.