Machine perfusion and innovations in liver transplant preservation

The use of ex vivo machine preservation/per-fusion (MP) remains investigational in clinical liver transplantation. MP is a platform that provides continuous circulation of nutrients and metabolic substrates and oxy-gen during the ex vivo period. Over the last few years, several groups worldwide have been actively translating MP into the clinical arena for liver transplantation. Groups are investigating ex vivo MP at various temperatures and with various perfusates and devices. There have been several promising preliminary clinical series of liver hypothermic MP (HMP) published over the last 5 years. Normothermic MP (NMP) is currently undergoing clinical investigation in Europe with promising clinical reports. There has been excellent clinical experience with HMP in small series including those recovered from extended criteria donors and donation after cardiac death donors. While some variability exists in technique, all clinical HMP series to date have reported improved outcomes with reductions in early allograft dysfunction, biliary complications, and reduced hospital length of stay. These benefits, together with the development of innovative portable MP devices and further adoption by more centers worldwide, have ‘‘broken the ice’’ for more widespread use of HMP and subsequent expanded elucidation of the benefits of MP in liver transplantation. Optimal temperatures and protocols are still a topic of debate.