Acquired and congenital heart disease can necessitate heart valve replacement. However, current heart valve substitutes are not considered ideal as they need anticoagulation, bearing the risk of bleeding when manufactured from non-organic material, or they degenerate when they derive from animals or human tissue donators (homografts) thereby leading to frequent reoperation especially in the young population. An ideal heart valve substitute would overcome these limitations and even have the potential to grow when implanted in pediatric patients.Haverich et al. have developed an implant for heart valves, which is better tolerated than the known alternatives and which has the potential for regeneration by autologous recellularization. Implants derive from donated homografts, which are chemically treated to inactivate potential microorganisms and viruses. The heart valves then are decellularized chemically, so that only connective tissue remains, the matrix of the decellularized heart valve (DHV). DHV has been examined in extensive animal studies, including immunological and toxicological analysis, long term and growth models, all of which have shown that the implant is well tolerated and spontaneously recellularized by the recipient.The proposed ESPOIR project is based on auspicious early clinical results in 45 children and young adults. In order to drive translation of this promising regenerative approach towards practical clinical use and to reduce the burden of congenital heart defects in particular, the ESPOIR consortium will undertake a prospective multi-centre trial to include at least 200 patients from 8 leading European Centres for Congenital Heart Surgery, for robust statistical evaluation of DHV in direct comparison to conventional heart valve substitutes.