Acute Kidney Injury Post-Liver Transplant Using Grafts Treated with Hypothermic Machine Perfusion: From Biology to Surgical Aspects

Many advantages have been reported with the use of machine perfusion (MP) to rescue extended criteria donor (ECD) grafts, improving both short- and long-term post-liver transplantation (LT) outcomes. Acute kidney injury (AKI) is a common post-LT complication associated with these grafts and may compromise patient outcomes and increase LT-related costs. The aim of the study was to analyze the incidence of AKI in recipients of MP-treated grafts compared with those receiving conventionally cold-stored (SCS) grafts, both before and after a propensity score matching (PSM). From a prospectively maintained database, LT recipients of MP-treated grafts were compared with SCS grafts transplanted in the same study period (January 2022-May 2025). PSM was performed based on donor risk index (DRI), macrosteatosis (≥ or <30%), and recipient NaMELD score using a 3:1 (MP vs. SCS) ratio. Of the 177 consecutive LTs, 30 were performed with MP-treated grafts (MP group) and 147 using SCS (SCS group). The MP group displayed more marginal characteristics: older age (72 vs. 62 years, <i>p</i> = 0.02), higher proportion of DCD (10% vs. 0, <i>p</i> = 0.04), and higher frequency of moderate steatosis (macro ≥ 30%, 10% vs. 2.7%, <i>p</i> = 0.09). AKI rates were similar between groups (63% vs. 45.6%, <i>p</i> = 0.16), as was the distribution across AKI stages. After PSM, donor and recipient characteristics were balanced, and AKI rates remained similar between groups (58.6% vs. 47.1%, <i>p</i> = 0.39). Donor diabetes and recipient age were independent predictors of AKI in multivariate analysis (donor diabetes OR 3.29, 95% CI 1.347-8.030; recipient age: OR 1.06, 95% CI 1.015-1.097, both <i>p</i> < 0.05). MCP-1 and TNF-α levels measured in the perfusate fluid within the first minutes of perfusion were positively correlated with post-LT creatinine peak (MCP-1, <i>p</i> = 0.00023, R = 0.58; TNF-α, <i>p</i> = 0.0004, R = 0.57). In conclusion, machine perfusion remains a valuable strategy for rescuing ECD liver grafts. In the current era-characterized by increasing use of machine-perfused grafts and extended criteria donors-recipients demonstrate postoperative renal outcomes comparable to those receiving conventionally preserved grafts.