Machine perfusion for liver transplantation: A concise review of clinical trials

With the increased use of extended-criteria donors, static cold storage has failed to provide optimal preservation of liver grafts, resulting in early allograft dysfunction and long-term complications. Machine perfusion (MP) is a beneficial alternative preservation strategy for donor livers, particularly for those considered to be of suboptimal quality, and could expand the limited donor pool.

A comprehensive search in PubMed, EMBASE, Ovid databases and ClinicalTrials.gov website was conducted using the medical subject heading terms "machine perfusion", "machine preservation", "liver transplantation", combined with free text terms such as "hypothermic", "normothermic" and "subnormothermic". The deadline for the search was September 30, 2017.

MP can be classified as hypothermic, subnormothermic, and normothermic with the temperature maintained at 0-12 °C, 25-34 °C and 35-38 °C, respectively. Twelve clinical trials of MP have been reported in recent years. MP effectively decreased AST/ALT level and the incidence of early allograft dysfunction. However, the graft and patient survival rate after MP were similar to static cold storage. The detailed clinical characteristics such as liver function, graft survival, patient survival and early allograft dysfunction were reviewed.

Clinical trial results showed that MP improves delayed graft function, primary non-function and biliary strictures. However, MP still requires validation in large clinical trials and the key parameters during MP still require optimization.