Graft quality assessment during machine perfusion in liver transplantation: a review of current evidence and emerging strategies.

Machine perfusion (MP) has transformed liver transplantation by enabling organ reconditioning, extending preservation times, and providing a dynamic platform for graft quality assessment. The ability to evaluate organ viability represents one of the most clinically impactful applications of this technology. As different perfusion modalities develop, distinct strategies have emerged to characterize graft viability. However, despite the growing evidence, significant heterogeneity remains in the parameters and thresholds employed, varying between each MP modality, as well as between centers. This review provides a comprehensive and critical synthesis of available evidence on viability assessment during each perfusion modality, and discusses promising new strategies in the race to the holy grail of viability assessment: prevention of both primary non-function (PNF) as well as the prediction of ischemic cholangiopathy (IC), so as to achieve tangible benefits in patient-centered outcomes.