As with all evolving new technologies, new generations of Melody valves were created in order to reduce current limitations and extend the spectrum of potential

clinical indications. Improvements brought to the Melody® valve during the last few years of development or currently in progress include: Device design improvements Delivery system improvements Patient selection Inhibitors,research,lifescience,medical improvements using three-dimensional echography and MRI Dilatation with high-pressure balloon after implantation (to reduce residual gradients) Stent-in-stent implantation Structural improvements to extend this technology to patients with native, dilated, and distensible RVOT These principles of percutaneous valve implantation are currently investigated in other off-label clinical Bleomycin datasheet settings. For instance, valves developed for trans-catheter replacement of the aortic valve were implanted in the pulmonary

position for patients with larger annulus.15 A new device allowing Inhibitors,research,lifescience,medical the implantation of a pulmonary valve in a RVOT previously repaired with a transannular patch is also currently investigated but not Inhibitors,research,lifescience,medical published yet. Tissue-Engineered Valved Conduits: Decellularized Scaffolds, Polymer Scaffolds, and in Situ Regeneration The ideal RV–PA conduit for reconstruction of the RVOT still does not Inhibitors,research,lifescience,medical exist. Cryopreserved homografts need a revision surgery in 36% and 90% of cases after 10 and 15 years, respectively.16–18 Hancock conduits need to be replaced after 10 years in 68% of cases, and 50% of Carpentier–Edwards Perimount® (Edwards Life-sciences, Irvine, CA, USA) valves (bioprosthetic stented valve Inhibitors,research,lifescience,medical made of bovine pericardium) implanted in children also have to be replaced after 5 years.19 Children younger than 2 years old operated with a Contegra® Medtronic conduit have to undergo a revision surgery in 67% of cases for failure.20 The reoperations needed to replace a failing conduit

carry a significant risk of mortality (1%–3%) and morbidity: hemorrhagic syndrome, cerebral aminophylline vascular accident, coronary damage, cardiac rhythm alterations, or infection. These complications translate into prolonged hospitalization and attendant costs. Surgical techniques have improved during the last three decades, but conduit failure and morbidity and mortality still occur (Table 1). Autologous pericardial valved conduits for RVOT reconstruction showed superb properties, but data for long-term follow-up are lacking.21 Table 1 Current Surgical Valved Conduits to Replace the Right Ventricular Outflow Tract. As a consequence of the limited treatment options and the requirements for repeat surgery in children as they grow, new alternatives were investigated to reconstruct the RVOT.