Short (2‐Hour) Non‐Oxygenated End‐Ischemic Hypothermic Perfusion Versus Cold Storage in the Setting of Renal Transplantation

Background: Kidney transplantation (KT) is the most effective treatment for end-stage renal disease. End-ischemic hypothermic machine perfusion (EI-HMP) has emerged as a promising method for preserving grafts before transplantation. This study aimed to compare graft function recovery in KT recipients of deceased brain-death (DBD) grafts preserved with EI-HMP versus static cold storage (SCS). The primary outcome was the rate of delayed graft function (DGF). Secondary outcomes included urine output, intensive care unit (ICU) stay, hospital stay duration, and survival rates. Methods: A retrospective, single-center observational study was conducted at Sapienza University of Rome, analyzing 313 KT patients between January 2014 and September 2021. Patients were stratified into two groups based on graft preservation methods (EI-HMP, n = 95; SCS, n = 218). A stabilized inverse probability treatment weighting (IPTW) method was employed to adjust for potential confounders. Results: There were no significant differences in DGF rates between the two groups (17.9% vs. 15.6% in SCS and EI-HMP cases, respectively; p = 0.75). EI-HMP group demonstrated a higher urine output on day 2 (p = 0.046), a shorter ICU stay (p < 0.0001), and a trend toward a shorter overall hospital stay (p = 0.07). No statistically significant differences were found between EI-HMP and SCS cases in 1- and 3-year overall survival rates (3.2% and 6.7% vs. 5.6% and 6.6%, respectively; log-rank p = 0.53) or in death-censored graft loss rates (5.4% and 8.9% vs. 5.7% and 7.3%, respectively; log-rank p = 0.88). In a sub-analysis of expanded criteria donors (ECD), EI-HMP demonstrated a protective effect by reducing the risk of DGF (OR = 0.31, 95% CI = 0.09–0.95; p = 0.047). Conclusion: EI-HMP was associated with certain short-term benefits, including increased urine output and reduced ICU stays, but showed no significant impact on long-term survival outcomes. A reduction in DGF rates was observed only in the ECD subgroup. Randomized controlled trials are necessary to further investigate the long-term clinical benefits of EI-HMP.