Hypothermic oxygenated machine perfusion (HOPE) preconditions liver grafts before transplantation. While beneficial effects on patient outcomes were demonstrated, biomarkers for viability assessment during HOPE are scarce and lack validation. This study aims to validate the predictive potential of perfusate flavin mononucleotide (FMN) during HOPE to enable the implementation of FMN-based assessment into clinical routine and to identify safe organ acceptance thresholds. FMN was measured in perfusate samples of 50 liver grafts at multiple time points. After transplantation, patients were followed up for development of early allograft dysfunction (EAD), transplantation, and 1-year survival. FMN concentrations were significantly higher for grafts that developed EAD at 5 and 60 minutes into HOPE (p = 0.008, p = 0.026). The strongest predictive potential of FMN for EAD was observed at 5 minutes of HOPE with an AUC of 0.744. Similarly, 5-minute FMN was predictive for 1-year mortality (p < 0.001), reaching a remarkable AUC of 0.890. Cutoffs for prediction of EAD (10.6 ng/mL) and early mortality (23.5 ng/mL) were determined and allowed risk stratification of grafts. Particularly, patients receiving low-risk grafts developed EAD in 9% of cases, while all patients survived the first postoperative year. In contrast, high-risk organs developed an incidence of EAD at 62%, accompanied by the necessity of retransplantation in 38% of cases. One-year mortality in the high-risk cohort was 62%. Evaluation of FMN as early as 5 minutes during HOPE allows for risk stratification of liver grafts. Low-risk grafts, according to FMN, display a negligible risk for patients. Yet, high-risk grafts are associated with increased risk for EAD, transplantation, and early mortality and should not be used for transplantation without further assessment.

Background: Corroborating evidence for the use of hypothermic oxygenated machine perfusion (HOPE) prior to orthotopic liver transplantation (OLT) suggests a beneficial effect in regard to biliary complications. Here, the authors aim to evaluate whether perfusion via portal vein alone (sHOPE) or via additional perfusion of the hepatic artery (dHOPE) have diverging impact on outcomes after OLT when compared to the use of static cold storage (SCS). Methods: Consecutive patients undergoing OLT at the Medical University of Vienna (2018–2023) were retrospectively analyzed. Donor organs were procured using SCS, or subjected to end-ischemic sHOPE or dHOPE. The severity of biliary complications was classified according to the degree of therapeutic intervention (endoscopic retrograde cholangiopancreatography or surgical revision). Results: Two hundred forty-seven patients were included (69 SCS, 76 sHOPE, and 102 dHOPE). Hospitalization was shorter for patients after HOPE (median in days: SCS=25 vs HOPE=20, P=0.019). Biliary complications were less frequent in patients after HOPE (SCS=37.7% vs HOPE=22.5%, P=0.015). A significantly lower incidence of surgical revisions for biliary complications was observed in the HOPE cohort (24.6% vs 11.8%, P=0.012). When evaluating outcome according to HOPE-modality, a significant reduction in biliary complications (P=0.006) and surgical revisions (P=0.002) was only observed in dHOPE patients in comparison to SCS. Further, only dHOPE was significantly associated with a reduced need for surgical revision for biliary complications upon univariable and multivariable logistic regression (odds ratio=0.336, P=0.011). Conclusion: HOPE leads to a reduction of biliary complications and associated surgical revisions. This effect seems to be primarily associated with use of dHOPE, while both methods appear as feasible options for preconditioning of donor grafts prior to OLT.

Background and Aims: Hypothermic oxygenated machine perfusion (HOPE) improves outcomes in orthotopic liver transplantation (OLT), but reliance on University of Wisconsin machine perfusion solution (UW-MPS) increases costs and logistical burden. Histidine-tryptophan-ketoglutarate (HTK) has potential as a single-solution alternative for HOPE. This study evaluated the safety and efficacy of HTK versus UW-MPS during HOPE. Methods: A retrospective, propensity score-matched cohort study including 46 patients who received donation after brain death (DBD) grafts that were preserved with HOPE at the Medical University of Vienna between May 2018 and October 2024 was conducted. A total of 23 patients received grafts perfused with HTK; another 23 patients transplanted with organs perfused with UW-MPS were matched based on recipient age and sodium model of end-stage liver disease score, donor age and sex, cold ischemia time, and perfusion time. Postoperative outcomes, perfusion parameters, and cost differences were assessed. Results: The HTK and UW-MPS cohorts demonstrated comparable perfusion dynamics and vascular resistance. While arterial pressure and flow were higher in the UW-MPS group, clinical outcomes—including early allograft dysfunction (47.8% each), ICU stay, and comprehensive complication index—were statistically similar. A trend toward fewer biliary complications (13.0% vs. 30.4%) and reduced hemodialysis requirement (17.4% vs. 30.4%) was observed in the HTK group. Use of HTK reduced perfusion-related costs by approximately EUR 560 per procedure. Conclusion: HTK is a viable alternative to UW-MPS during HOPE in OLT of DBD grafts, offering comparable short-term outcomes and relevant cost savings. Prospective studies are warranted to validate these findings and explore broader applications of single-solution perfusion strategies.