Comparing Early Graft Dysfunction Scores in Liver Transplantation After Ex-Situ Normothermic Machine Perfusion

As normothermic machine perfusion (NMP) maintains liver grafts in a near-physiologic state, uncoupling ischemia-reperfusion injury from the recipient, the validity of early graft dysfunction scores from the static cold storage (SCS) era are uncertain.

All liver grafts that were transplanted following NMP at our center between 08/19/2022 and 05/31/2024 were analyzed. We assessed associations between the early graft dysfunction scores and graft survival in the NMP era and identified factors linked to pronounced dysfunction.

Of 126 NMP-perfused liver grafts, seven (5.5%) were discarded after viability assessment. Among the 107 transplanted livers (41%-DBD, 59%-DCD), neither the liver graft assessment following transplantation (L-GrAFT7) nor the model for early allograft function (MEAF) scores correlated with early graft loss. Early allograft dysfunction (EAD) occurred in 40% of cases and was associated with lower 6‑month graft survival compared with non-EAD cases (89% vs 100%, p = 0.04). Higher donor BMI, longer agonal and anastomosis times, post-reperfusion syndrome, and suboptimal pump parameters (impaired glucose metabolism, delayed lactate clearance, increased bicarbonate use, elevated perfusate transaminases) correlated with EAD. Grafts exceeding conventional viability thresholds (increased bicarbonate use to maintain pH >7.2, lactate rise >2 mmol/L within 6 h post-clearance, and perfusate ALT >6000 U/L) were successfully utilized without compromising short-term outcomes.

In the NMP era, EAD identifies a high-risk subgroup with inferior short-term graft survival. Trajectory-based scores did not correlate with early graft loss. Pump variables may help guide decision-making when considering the use of liver grafts with an increased likelihood of EAD in select recipients.