The role of normothermic machine perfusion in liver transplantation.

To expand the donor pool of suitable organs for transplantation, there is an increased interest in utilizing extended criteria donor grafts (ECD). Ex-situ machine perfusion has shown to be a promising new modality in the organ preservation field to reduce injury and recover ECD liver grafts. Machine perfusion (MP) is considered a significant improvement in the field of transplantation over the past 20 years. Normothermic machine perfusion has entered the clinical arena in the last decade and has shown promising results to improve the quality of marginal organs and to increase the pool of liver grafts. It allows assessment of viability and function of grafts prior to transplantation. In addition, it has the potential to serve as a platform for pharmacologic organ treatment and graft optimization. Machine perfusion moved from the experimental phase to a more mature phase after safety was confirmed by initial clinical trials. Now, it is time to confirm its superiority and cost-effectiveness before a broader clinical use. In this paper we review the history, current status including outcomes of all clinical trials, limitations, and future trends of normothermic machine preservation.