Hypothermic Oxygenated Perfusion (HOPE) of Human Liver Grafts

The purpose of this study is, in a randomized trial, to test a newly developed machine perfusion technique of human liver allografts before transplantation.

Ischemia-reperfusion injury is universal in organ transplantation and leads to varying degrees of graft dysfunction. Despite this fact, the preservation method in organ transplantation has been left unchanged for many years and remains simple static cold storage. Given the scarce donor supply, an increasing number of so called marginal or extended criteria donor organs have been used for liver transplantation, grafts which were previously rarely considered. In addition, allocation policy has changed in many countries, and livers are currently often distributed by the severity of the recipient's disease. As a result, transplant candidates present sicker, with higher MELD (Model for end stage liver disease) scores, at the time of transplant,and the risk of graft dysfunction or even failure due to reperfusion injury is high after the use of marginal livers in sick recipients.

Machine liver perfusion techniques have been significantly improved during the past decade to decrease reperfusion injury, and a number of promising results show beneficial effects in various animal transplant models by either normothermic or hypothermic oxygenated continuous liver perfusion. These techniques generally require machine liver perfusion immediately after organ procurement. However, continuous perfusion has several drawbacks, including major logistic efforts and risk of organ damage during perfusion and transport.

Our group, therefore, focused on the practicability of machine liver perfusion. We developed an endischemic hypothermic oxygenated perfusion (HOPE) concept through the portal vein only. This technique can be easily applied in the operation room shortly before transplantation of the recipient, thus after organ transport and back table preparation.

Recently, the beneficial effect of a similar approach has been confirmed in human liver grafts by a phase I non randomized trial. These results prove feasibility and safety of an endischemic hypothermic machine perfusion approach and warrant further randomized studies.