Zhang, Mingyi

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.

4235 Background: Malignant portal vein tumor thrombus (PVTT) arising from hepatic metastases is associated with poor prognosis, rapid hepatic decompensation, and limited effective local treatment options despite systemic therapy. In real-world practice, local treatment intensity is frequently adapted to disease burden and treatment response. We evaluated outcomes of a risk-adapted, step-up local treatment strategy using microwave ablation (MWA) alone or in combination with iodine-125 (I-125) seed implantation for patients with malignant PVTT. Methods: We retrospectively reviewed patients with hepatic metastases treated with MWA with or without I-125 seed implantation between 2023 and July 2025. In clinical practice, MWA alone was preferentially used for patients with relatively limited disease burden, while MWA plus I-125 was employed as an escalation strategy for patients with more advanced PVTT or disease progression following MWA alone. The primary endpoint was PVTT-directed local outcome, defined as portal vein patency and/or local control of tumor thrombus on follow-up imaging. Secondary endpoints included progression-free survival (PFS), overall survival (OS), hepatic function changes, and treatment-related toxicity. Survival analyses were considered exploratory. Results: A total of 73 patients were included, of whom 50 were treated with MWA alone and 23 with MWA plus I-125 seed implantation. Patients receiving MWA plus I-125 demonstrated more advanced disease characteristics, including universal presence of PVTT and higher disease stage, consistent with treatment escalation by disease severity. Among patients with PVTT, MWA plus I-125 achieved portal vein patency and/or local control in 65% at first follow-up imaging. Treatment-related toxicities were manageable, with no unexpected grade ≥3 adverse events attributable to I-125 implantation. Median PFS was 11.5 months in patients treated with MWA alone and 9.9 months in patients treated with MWA plus I-125, consistent with greater baseline disease burden in the latter group. Conclusions: MWA alone and MWA plus I-125 function as complementary components of a risk-adapted, step-up local treatment strategy for malignant PVTT from hepatic metastases. Escalation to MWA plus I-125 appears feasible in patients with advanced or refractory PVTT and demonstrates a potential signal for improved PVTT-directed local control and portal vein patency. Prospective studies focused on PVTT-specific endpoints are warranted.