Transplantation of Extended Criteria Donor Livers Following Continuous Normothermic Machine Perfusion Without Recooling

Abstract
Introduction: Traditional liver transplant strategies with cold preservation usually result in ischemia reperfusion injury (IRI) to the donor liver. Regular normothermic machine perfusion (NMP) donor livers suffer IRI twice. Here, we aimed to introduce a novel technique called continuous normothermic machine perfusion (NMP) without recooling to avoid a second IRI and its application in livers from extended criteria donors (ECDs). Materials and methods: Seven donor livers transplanted following continuous NMP without recooling, 7 donor livers transplanted following standard NMP and 14 livers under static cold storage (SCS) were included in this study. Perioperative outcomes were recorded and analyzed between groups. Result: During the NMP without a recooling procedure, all livers cleared lactate quickly to normal levels in a median time of 100 minutes (IQR 60~180) and remained stable until the end of perfusion. In the NMP without recooling and standard NMP groups, posttransplant peak aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were both significantly lower than those in the SCS group (P=0.0015 and 0.016, respectively). The occurrence rate of early allograft dysfunction (EAD) was significantly lower in the NMP without recooling group than in the SCS group (P=0.022), while there was no difference in the NMP group with or without recooling (P=0.462). Conclusion: Our pilot study revealed a novel technique designed to avoid secondary IRI. This novel technique is shown to have at least a comparable effect to the standard NMP, though more data are needed to show its superiority in the future.