Abstract
Currently, various materials are used for the right ventricular outflow tract reconstruction (RVOTR) in the treatment of congenital heart disease; however, from the view point of longevity, none of them yield satisfactory results. We have originally developed a tri-valved conduit made of expanded polytetrafluoroethylene (ePTFE) for RVOTR. This valved conduit consists of an ePTFE graft with bulging sinuses; to the inside of the graft are attached fan-shaped valves made of 0.1 mm thick ePTFE membrane. This valved conduit has been supplied for 52 institutes in Japan, where 325 patients (aged 15 days to 56.8 years old) received the implantation of this conduit between February 2002 and January 2011. Notably, an improved reoperation-free survival (95.4% at 10 years) and preventative effects on pulmonary insufficiency (moderate 4.7%, severe 0.3%) was observed in the mean follow-up of 3.6 years. This improved outcome may partly be attributable to the excellent biocompatibility and low antigenicity of ePTFE, which is expected to prevent calcification and immunological rejection, both of which are the main causes of graft degeneration in homografts and xenografts. Moreover, our experimental study using pediatric right heart circulation model showed that bulging sinuses and fan-shaped leaflets produced two important fluiddynamical properties; that is, vortex flow in the sinus and laminar flow in the conduit, which might also have contributed to the better function of the valves. In conclusion, excellent biocompatibility of ePTFE and fluiddynamical properties provided by bulging sinuses and fan-shaped leaflets are the rationale for the excellent clinical results of our valved conduit.
