Normothermic Oxygenated Perfusion (NMP) Viability Testing Before Transplantation of Discarded Livers

Liver transplantation (LT) is a highly effective treatment for end-stage liver disease and early-stage primary liver cancer. As such, the demand for donor livers greatly exceeds supply; in 2021 in France, 12.9% of patients on the waitlist either died or were delisted for worsening of their condition. However a substantial number of perfectly viable organs are wrongly discarded based on a highly subjective assessment as the level of acceptance varies widely depending on the physician's judgement. The idea of using Normothermic Machine Perfusion (NMP) not only to preserve the liver graft but also for selection purposes is a concept that has been already investigated. A few trials have analyzed the value of normothermic perfusion to assess rejected liver grafts. Several teams demonstrated that NMP provides a tool to assess organ viability pre-transplantation as the liver is able to maintain an almost physiological metabolism. These preliminary results came from small samples, 45% of which originated from donation after circulatory death (DCD). They need confirmation in a larger sample of organs from donors with brainstem death (DBD), adapted to the French liver allocation system. This trial will reproduce and confirm the results of the previous studies in order to establish viability testing as the de facto method for high-risk or rejected grafts. It will also validate existing viability markers so as to define a new standard for viability testing using NMP.