• extendend criteria donors
• machine perfusion
• normothermic machine perfusion
• dual hypothermic oxygenated perfusion
• donation after cardiac death
• liver transplantation

Introduction
Over the years, new strategies have allowed to increase the number of transplantable livers, expanding the selection criteria to the extendend criteria donors (ECD), for example elderly donors and donation after cardiac death (DCD). Unfortunately, these grafts present a higher incidence of liver damage and biliary complications. The introduction of the Machine Perfusion (MP), an ex situ perfusion technique, allows a partial reconditioning of the organ before transplant.

Methods
All DCD liver transplants performed at Unit of Liver Surgery and Transplantation of Pisa from 1 January 2018 to 31 December 2022 were included in the study. In addition transplants from DBD (Donation after brain death) donors subjected to Normothermic machine perfusion (NMP) or Dual hypothermic oxygenated perfusion (D-HOPE) performed in the same period were included.
Since December 2020 the DCD transplants performed at our Center have been included in a randomized and multicenter study protocol called DCD-Net, with the aim of comparing the results of D-HOPE vs NMP in DCD liver transplants.

Results
30 DCD transplants were performed at our Center: 11 grafts underwent D-HOPE, while NMP was performed on 19 grafts. In the NMP group there were 6 cases of early allograft dysfunction (EAD) and one case of re-transplantation; survival was found to be 89% at one and 77% at three years. In the D-HOPE group there were 5 cases of EAD; survival was found to be 80% at one and 3 years. Six patients (5 NMP, 1 D-HOPE) presented biliary complications. The last 20 DCDs have been entered in the DCD-Net protocol; the only statistically significant difference between the two groups was the number of EAD, higher in the D-HOPE gioup (p = 0.025).
There were 29 DBD grafts subjected to MP, 10 subjected to NMP and 19 to D-HOPE. No significant differences were found between the two groups.

Discussion
The results of the DCD donation were in line with the literature regarding biliary complications, graft loss and re-transplantation. More unfavorable results were obtained concerning hospitalization days, perioperative and one-year mortality. The use of ex situ perfusion systems has considerable potential for a greater procurement of organs. However, no decisive results have been obtained to favor the use in NMP or D-HOPE, mainly due to the small number of transplants performed from DCD donors.