Machine Perfusion Across Marginal Liver Grafts: Benefits and Challenges.

Liver transplantation is the definitive therapy for end-stage liver disease, yet persistent organ shortages result in approximately 10% of recovered livers being discarded, with markedly higher discard rates among marginal grafts from elderly donors, donation after circulatory death (DCD), and those with macrovesicular steatosis. Machine perfusion (MP) has emerged as a paradigm-shifting preservation strategy with the potential to safely expand the usable donor pool. This narrative review examines the current evidence for three MP modalities-hypothermic machine perfusion (HMP), normothermic machine perfusion (NMP), and normothermic regional perfusion (NRP)-across various marginal donor populations, including elderly donors, steatotic grafts, donors with infectious diseases, and split liver transplantation. Current evidence demonstrates that MP significantly increases utilization of steatotic grafts with up to an eightfold rise in usage of severely steatotic organs. HMP consistently reduces non-anastomotic biliary strictures and early allograft dysfunction across donor types, while NMP enables real-time viability assessment and reduces post-reperfusion syndrome in steatotic grafts. NRP shows particular benefit in DCD organs, reducing biliary complications and improving one-year survival. Additionally, MP extends preservation times enabling next-day split liver transplantation and shows promise as a platform for ex situ antiviral therapy. Despite compelling evidence supporting MP in marginal grafts, widespread adoption remains constrained by high costs, logistical complexity, and the absence of standardized protocols. Future progress will require multicenter studies evaluating long-term outcomes alongside consensus-driven implementation frameworks.