Carlis, Riccardo De

Abstract Background Machine perfusion represents the most significant breakthrough in liver transplantation (LT) since the discovery of cyclosporin. Yet, the optimal perfusion strategy remains unsettled. Randomized trials demonstrate that hypothermic oxygenated perfusion (HOPE) improves graft survival and function and reduces ischemic cholangiopathy, whereas normothermic machine perfusion (NMP) decreases post-transplant injury. Real-world comparisons are lacking and challenging due to heterogeneity in donor-recipient risk profiles and regional differences. Aims To compare real-world outcomes of HOPE and NMP in LT. Methods We analyzed consecutive NMP-preserved LTs from seven North American centers between 2021 and 2024. We compared NMP to the European HOPE-REAL cohort, comprising HOPE-treated LTs from 22 centers between 2012 and 2021. Analyses were stratifyied by graft type and risk category and adjusted for donor age, donor risk index, and balance of risk score using entropy balancing. Results A total of 470 NMP and 1202 HOPE-treated grafts were analyzed, revealing major differences in risk profiles (Figure 1). In NMP, death-censored graft survivals at 1, 2, and 3 years were >95% in donation after brain death (DBD) and >94% in donation after circulatory death (DCD) grafts. Comparable outcomes were observed in the HOPE cohort with >93%, in DBD, and >87% in DCD after up to 3 years, despite significantly higher donor age and longer functional warm ischemia in the HOPE DCD cohort (Figure 2). After risk adjustment, death-censored graft survival remained similar between both modalities (Table 1). Non-anastomotic biliary stricture rates after DCD-LT were comparable (8.5% vs. 12.4%), independent of whether continuous or end-ischemic NMP was performed. Conclusion This first transatlantic real-world report demonstrates excellent outcomes with both NMP and HOPE despite higher graft risk in Europe. Machine perfusion is the new standard of care in LT, while further understanding is needed regarding the distinct benefits of each modality across risk profiles.Figure 1.Graft risk in NMP and HOPE stratified by graft type. Benchmark case was defined as primary transplant with MELD <20 and BAR score <9, extended criteria as either BMI >30kg/m2, donor age >65 years, CIT >12h. DCD grafts were categorized as definedFor image description, please refer to the figure legend and surrounding text. Figure 2.Death-censored graft survival in liver transplantation following NMP and HOPE stratified by graft type. Abbreviations: NMP (Normothermic Machine Perfusion), HOPE (Hypothermic Oxygenated Perfusion), DBD (Donation after Brain Death), DCD (Donation after circulatory death)For image description, please refer to the figure legend and surrounding text. Table 1.Risk-adjusted comparison of death-censored graft survival between NMP and HOPE.For image description, please refer to the figure legend and surrounding text.