Taner, C. Burin

ABSTRACT Background With increasing use of donation after circulatory death (DCD) donor grafts, the need for accurate risk‐stratification tools in liver transplantation has become critical. Machine perfusion has been shown to improve both graft and patient survival. However, existing prediction models were developed in the static cold storage (SCS) era and their accuracy when using machine perfusion remains unknown. Our study aims to study if current scoring systems can predict graft and patient survival for DCD livers preserved using normothermic machine perfusion (NMP). Methods This was a retrospective study of patient and graft survival in a two‐center U.S. DCD NMP cohort ( n = 532) between January 2022 and December 2024. Predicted graft and patient survival rates were obtained from established risk scoring systems, including the United Kingdom DCD risk score (UK‐DCD), Early Allograft Dysfunction (EAD) Olthoff score, Liver Graft Assessment Following Transplantation (L‐GrAFT 7 ) score, Donor Risk Index (DRI), Balance of Risk (BAR) score, and Survival Outcomes Following Liver Transplant (SOFT) score. Model discrimination was assessed using receiver operating characteristic (ROC) curves (C‐statistics). Survival outcomes across risk strata were estimated and compared using Kaplan‐Meier (KM) analysis. Results Across scoring systems, predicted survival consistently underestimated actual graft and patient survival in the NMP DCD cohort. The DRI, SOFT, EAD and L‐GrAFT 7 did not demonstrate predictive value. UK‐DCD predicted ≤85% and <40% 1‐year graft survival for its high‐risk and “futile” groups, whereas observed rates were 93.7% and 86.8%. BAR low‐risk predicted >60% 5‐year survival but 94.2% was observed; the high‐risk group predicted <60% and observed was 53.3%. Despite underestimations and generally poor C‐statistics, in KM stratification, high‐risk groups still showed statistical differences in the UK‐DCD categories ( p = 0.007), and in SOFT score groups ( p < 0.001). No statistical difference was seen in BAR ( p = 0.36), DRI ( p = 0.36), EAD ( p = 0.12), or L‐GrAFT 7 ( p = 0.75). Conclusion Existing liver transplant risk scores show limited predictive value for donor‐related risk factors in the NMP era, whereas recipient‐related factors remain somewhat predictive, despite overestimating risk. Early allograft dysfunction metrics were not reliable predictors of short or long‐term outcomes. Future risk models should integrate machine‐perfusion parameters and refined donor variables to reflect outcomes more accurately in contemporary DCD liver transplantation.

Donation after circulatory death (DCD) liver transplants (LTs) are associated with increased risk of post-LT acute kidney injury (AKI). This retrospective study aimed to examine the effect of continuous normothermic machine perfusion (NMP) on the incidence and stage of AKI in DCD LT. The incidence of AKI within 48 hours was compared between 507 NMP-DCD and 472 static cold storage (SCS)-DCD LT transplanted between January 1, 2016, and December 31, 2024. AKI developed in 337 (34%) patients. On univariate analysis, AKI rate was lower in NMP-DCD compared with SCS-DCD (28% vs. 41%, p <0.001). Stages 2 and 3 AKI at 48 hours and renal replacement therapy (RRT) within the first 3 weeks were also lower in NMP-DCD compared with SCS-DCD ( p <0.001). After adjusting for multiple recipient, donor, and intraoperative factors using multivariate logistic regression, NMP-DCD was independently associated with a 37% lower odds of AKI (aOR: 0.63, CI: 0.46–0.85, p =0.003) and 55% lower odds of stages 2 and 3 AKI (aOR: 0.45, CI: 0.29–0.69, p <0.001) compared with SCS-DCD. To mitigate for the era effect and other unmeasured confounders, an inverse probability of treatment weighting (IPTW) analysis was performed using a propensity score model with average treatment effect (ATE). After weighting for multiple factors, NMP-DCD was associated with lower odds of AKI at 48 hours (OR: 0.65, CI: 0.53–0.81, p =0.001), stages 2 and 3 AKI at 48 hours (OR: 0.60, CI: 0.42–0.85, p =0.02), and RRT at day 7 (OR: 0.31, CI: 0.13–0.65, p =0.003) compared with SCS-DCD. In conclusion, compared with SCS-DCD, NMP-DCD was independently associated with lower odds of AKI at 48 hours, of stages 2 and 3 AKI at 48 hours from LT, and of RRT requirement at day 7 from LT, an effect that extended for the first 3 post-LT weeks.

Importance Ischemia-reperfusion injury contributes to graft dysfunction after liver transplant. Hypothermic oxygenated perfusion (HOPE) has been shown to improve liver function, but its benefit in extended criteria donors in a US population remains unclear. Objective To assess whether back-to-base portal-venous HOPE impacts outcomes after liver transplant in the US. Design, Setting, and Participants The Bridge to HOPE Trial is a multicenter, randomized, open-label trial with 1-year follow-up. The study took place at 15 US liver transplant centers and patients were enrolled between January 2021 and May 2023. Central assessment of complications and cholangiograms for nonanastomotic biliary strictures (NAS) was blinded to treatment arm. Participants included 219 recipients of extended-criteria donor livers after brain death (DBD) and after circulatory death (DCD) who were randomized 1:1 to HOPE after static cold storage (SCS) (n = 109) or SCS only (n = 110). Randomization was performed after liver inspection and acceptance for transplant. Data were analyzed from December 2024 to July 2025. Intervention After SCS and transport, livers underwent portal-venous HOPE until implant, using the VitaSmart HOPE System. Main Outcomes and Measures The primary efficacy end point was early allograft dysfunction (EAD). Other main outcomes included model for early allograft function (MEAF) score, hospital length of stay (LOS), patient and graft survival, and biliary complications. Additional post hoc analyses were performed. Results Overall, 219 patients (82 female [37.4%] and 137 male[62.6%]) were included (DCD, 57 of 219 [26%]) with 97% (212 of 219) completing 12-month follow-up. EAD incidence was 20.2% (22 of 109) with HOPE vs 37.3% (41 of 110) with SCS (rate difference, −17.1%; 95% CI, −27.2 to −7.0; noninferiority P &amp;lt; .001; superiority P = .005). HOPE treatment led to significantly lower MEAF mean (SD) scores (HOPE group, 4.28 [1.75]; control group, 4.82 [1.85]; mean difference, −0.54; 95% CI, −1.02 to −0.06; P = .03) and shorter median LOS (hazard ratio, 1.32; 95% CI, 1.01-1.73; P = .04). NAS on imaging and 1-year survivals were comparable between groups (patients: HOPE group, 106 of 109 [97.2%] vs SCS, 106 of 110 [96.4%]; graft: HOPE group, 104 of 109 [95.4%] vs SCS, 102 of 110 [92.7%]). Post hoc analyses showed numerically less graft loss due to NAS after HOPE (4 vs 1) and less major complications (Clavien-Dindo classification ≥IIIa) per patient, respectively. Conclusions and Relevance Back-to-base portal-venous HOPE was compared with SCS alone for extended risk DBD and DCD livers. The HOPE approach was safe and associated with reduced EAD, MEAF score, and LOS. These findings support the use of HOPE as a pragmatic strategy to improve early posttransplant outcomes. Trial Registration ClinicalTrials.gov Identifier: NCT05045794 .