From Rescue to Risk: Challenges and Controversies in Pushing the Boundaries of Organ Utilization by Machine Perfusion.

The ongoing shortage of donor livers has prompted the use of extended criteria donors (ECD) and the development of ex-situ machine perfusion (MP) to expand the transplantable organ pool. MP has transformed liver transplantation (LT) by improving preservation, enabling better logistics, and allowing real-time viability assessment that is, a process aimed at predicting liver function after transplantation based on MP parameters. Although viability assessment has been proposed to safely expand donor pool and improve LT outcomes, it remains inconsistent. This article will summarize currently available assessment protocols and recapitulate studies exploring emerging viability biomarkers, discussing the need for an operational definition of viability assessment and its implications for the design of future studies on the subject.