Right Ex-situ split grafts for adult liver transplantation - A Multicenter Benchmarking Analysis.

OBJECTIVE: To analyse outcomes after adult right ex-situ split graft liver transplantations (RSLT) and compare with available outcome benchmarks from whole liver transplantation (WLT). SUMMARY BACKGROUND DATA: Ex-situ SLT may be a valuable strategy to tackle the increasing graft shortage. Recently established outcome benchmarks in WLT offer a novel reference to perform a comprehensive analysis of results after ex-situ RSLT. METHODS: This retrospective multicenter cohort study analyzes all consecutive adult SLT performed using right ex-situ split grafts from 01.01.2014 to 01.06.2022. Study endpoints included 1 year graft and recipient survival, overall morbidity expressed by the comprehensive complication index (CCI©) and specific post-LT complications. Results were compared to the published benchmark outcomes in low-risk adult WLT scenarii. RESULTS: In 224 adult right ex-situ SLT, 1y recipient and graft survival rates were 96% and 91.5%, within the WLT benchmarks. The 1y overall morbidity was also within the WLT benchmark (41.8 CCI points vs. <42.1). Detailed analysis, revealed cut surface bile leaks (17%, 65.8% Grade IIIa) as a specific complication without a negative impact on graft survival. There was a higher rate of early hepatic artery thrombosis (HAT) after SLT, above the WLT benchmark (4.9% vs. ≤4.1%), with a significant impact on early graft but not patient survival. CONCLUSION: In this multicentric study of right ex-situ split graft LT, we report 1-year overall morbidity and mortality rates within the published benchmarks for low-risk WLT. Cut surface bile leaks and early HAT are specific complications of SLT and should be acknowledged when expanding the use of ex-situ SLT.

HOPE Mitigates Ischemia-Reperfusion Injury in Ex-Situ Split Grafts: A Comparative Study With Living Donation in Pediatric Liver Transplantation.

Optimizing graft preservation is key for ex-situ split grafts in pediatric liver transplantation (PSLT). Hypothermic Oxygenated Perfusion (HOPE) improves ischemia-reperfusion injury (IRI) and post-operative outcomes in adult LT. This study compares the use of HOPE in ex-situ partial grafts to static cold storage ex-situ partial grafts (SCS-Split) and to the gold standard living donor liver transplantation (LDLT). All consecutive HOPE-Split, SCS-Split and LDLT performed between 2018-2023 for pediatric recipients were included. Post-reperfusion syndrome (PRS, drop ≥30% in systolic arterial pressure) and reperfusion biopsies served as early indicators of IRI. We included 47 pediatric recipients (15 HOPE-Split, 17 SCS-Split, and 15 LDLT). In comparison to SCS-Split, HOPE-Split had a significantly shorter cold ischemia time (CIT) (470min vs. 538 min; p =0.02), lower PRS rates (13.3% vs. 47.1%; p = 0.04) and a lower IRI score (3 vs. 4; p = 0.03). The overall IRI score (3 vs. 3; p = 0.28) and PRS (13.3% vs. 13.3%; p = 1) after HOPE-Split were comparable to LDLT, despite a longer CIT (470 min vs. 117 min; p < 0.001). Surgical complications, one-year graft, and recipient survival did not differ among the groups. In conclusion, HOPE-Split mitigates early IRI in pediatric recipients in comparison to SCS-Split, approaching the gold standard of LDLT.

Liver transplantation of partial grafts after ex situ splitting during hypothermic oxygenated perfusion-The HOPE-Split pilot study.

Partial liver grafts from ex situ splitting are considered marginal due to prolonged static cold storage. The use of ex situ hypothermic oxygenated perfusion (HOPE) may offer a strategy to improve preservation of ex situ split grafts. In this single-center pilot study, we prospectively performed ex situ liver splitting during HOPE (HOPE-Split) for adult and pediatric partial grafts over a 1-year period (November 1, 2020 to December 1, 2021). The primary safety endpoint was based on the number of liver graft-related adverse events (LGRAEs) per recipient, including primary nonfunction, biliary complications, hepatic vascular complications, and early relaparotomies and was compared with consecutive single-center standard ex situ split transplantations (Static-Split) performed from 2018 to 2020. Secondary endpoints included preservation characteristics and early outcomes. Sixteen consecutive HOPE-Split liver transplantations (8 HOPE-Split procedures) were included and compared with 24 Static-Splits. All HOPE-Split grafts were successfully transplanted, and no graft loss nor recipient death was encountered during the median follow-up of 7.5 months (interquartile range, 5.5-12.5). Mean LGRAE per recipient was similar in both groups (0.31 ± 0.60 vs. 0.46 ± 0.83; p = 0.78) and split duration was not significantly increased for HOPE-Split (216 vs. 180 min; p = 0.45). HOPE-Split grafts underwent perfusion for a median of 125 min, which significantly shortened static cold storage (472 vs. 544 min; p = 0.001), whereas it prolonged total ex vivo preservation (595 vs. 544 min; p = 0.007) and reduced neutrophil infiltration on reperfusion biopsies (p = 0.04) compared with Static-Split. This clinical pilot study presents first feasibility and safety data for transplantation of partial liver grafts undergoing ex situ split during HOPE and suggests improved preservation compared with static ex situ splitting. These preliminary results will allow to set up large-scale trials on the use of machine perfusion in pediatric and split-liver transplantation.