Patients with pediatric prostheses suffer from mismatch and early calcification, which causes a high number of reoperations Methods: Expandable Polyurethane Stent Valve – EPSV, is composed by a flexible polyurethane (PU) leaflets is grown on the top of an expandable cobalt-chrome alloy stent, including the formation of three leaflets. Physical, Hydrodynamic, Animal studies, were performed following: ISO 5840-3,2015. Results: Physical tests. Result of study of surface scanning of pre and post crimp stent, showed no structural modification of the PU. Hydrodynamic test showed a pressure gradient oscillation between 5 to 20mm, in basal or stress condition respectively. Experimental studies. Sheep were subjected to 3D echoDoppler study, in 6th follow-up months, which showed satisfactory hemodynamic performance, with low transvalvular gradient (M = 6.60 mm Hg). Ultrastructural Study: Six stents were explanted after 20 days to 21 months of follow-up to Ultrastructural analysis. All of which revealed no presence of calcium growth and prostheses structure was intact. Conclusions: Association between: stent - design and PUleaflets, allowed acceptable hemodynamic performance, regardless of the stent valve diameter. The resistance of polyurethane to crimping and the lack of calcification of leaflets, are advantages that will allow greater durability of the prosthesis. This new concept of synthetic expandable stent valve could be a viable option in growing patients

Keywords : Stent, Valve, Pulmonary, Synthetic, Catheter