*Purpose: There is accumulating clinical evidence of the benefit of normothermic ex-vivo machine perfusion (NMP) compared with traditional static cold storage of liver allografts prior to transplantation in prevention of preservation injury, amelioration of allograft dysfunction, and ischemic cholangiopathy, especially in marginal or increased donor risk index livers or donation after cardiac death (DCD) allografts. The University of Maryland Medical Center participated in the first large randomized controlled trial comparing preservation of liver allografts with NMP using the OrganOx metra® device versus traditional static cold storage in clinical liver transplantation.

*Methods: Liver allografts were randomized at the time of procurement to the experimental arm (ex-vivo machine perfusion) or the control arm (static cold storage) prior to transplantation. The primary outcome is incidence of early allograft dysfunction (EAD) as defined by Olthoff et al. Secondary outcomes include incidence of post-reperfusion syndrome in the postoperative period (based on blood pressure and vasopressor requirements), evidence of biliary complications, severity of ischemia-reperfusion injury based on pre- and post-reperfusion biopsies, and patient and graft survival. In addition, analysis of health economic implications/feasibility of allograft preservation with NMP was examined.

*Results: 11 livers were randomized and subsequently transplanted, 6 to the machine perfusion arm and 5 to the traditional static cold storage arm. There was one DCD liver in each group. Biochemical liver function was assayed in the postoperative period. There was one occurrence of early allograft dysfunction in both arms, both times for AST greater than 2000. Results of the entire multicenter randomized controlled trial are pending publication.

*Conclusions: Ex-vivo machine perfusion has the potential to transform organ preservation, expanding the donor pool and leading to a clinically important increase in the number and quality of liver transplants, and decreasing waitlist time for patients with end stage liver disease. The University of Maryland experience with the OrganOx metra® device in the context of a large multicenter RCT comparing the efficacy of normothermic ex-vivo perfusion as a preservation modality is duly reported herein; preliminary results are encouraging.

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