Abstract
Machine perfusion (MP) preservation is potentially one of the most significant improvements
in the field of liver transplantation in the last 20 years, and it has been considered
a promising strategy for improved preservation and ex situ evaluation of extended
criteria donor (ECD) organs. However, MP preservation adds significant cost and logistical
considerations to liver transplantation. MP protocols are mainly classified according
to the perfusion temperature with hypothermic machine perfusion (HMP) and normothermic
machine perfusion (NMP) being the two categories most studied so far. After extensive
preclinical work, MP entered the clinical setting, and there are now several studies
that demonstrated feasibility and safety. However, because of the limited quality
of clinical trials, there is no compelling evidence of superiority in preservation
quality, and liver MP is still considered experimental in most countries. MP preservation
is moving to a more mature phase, where ongoing and future studies will bring new
evidence in order to confirm their superiority in terms of clinical outcomes, organ
utilization, and cost-effectiveness. Here, we present an overview of all preclinical
MP studies using discarded human livers and liver MP clinical trials, and discuss
their results. We describe the different perfusion protocols, pitfalls in MP study
design, and provide future perspectives. Recent trials in liver MP have revealed unique
challenges beyond those seen in most clinical studies. Randomized trials, correct
trial design, and interpretation of data are essential to generate the data necessary
to prove if MP will be the new gold standard method of liver preservation.
Keywords
ex situ machine perfusion - liver transplantation - extended criteria donors - outcomes
- clinical trials - organ preservation
