Liver Transplantation for Hepatocellular Carcinoma in the Era of Immune Checkpoint Inhibitors.

Hepatocellular carcinoma (HCC) remains the leading oncological indication for liver transplantation (LT), with evolving and broadened inclusion criteria. Immune checkpoint inhibitors (ICIs) gained a central role in systemic HCC treatment and showed potential in the peri-transplant setting as downstaging/bridging therapy before LT or as a treatment for HCC recurrence following LT. However, the antagonistic mechanisms of action between ICIs and immunosuppressive drugs pose significant challenges, particularly regarding the risk of acute rejection (AR). This review analyzes the main signaling pathways targeted by ICI therapies and summarizes current studies on ICI therapy before and after LT. The literature on this topic is limited and highly heterogeneous, precluding definitive evidence-based conclusions. The use of ICIs before LT appears promising, provided that a sufficient wash-out period is implemented. In contrast, the results of post-LT ICI therapy do not support its wide clinical application due to high AR rates and overall poor response to treatment. In the future, modern graft preservation techniques might support the selection of good ICI responders, but data from high-level studies are urgently needed.

Long-term outcomes after hypothermic oxygenated machine perfusion and transplantation of 1,202 donor livers in a real-world setting (HOPE-REAL study).

BACKGROUND & AIM: We aimed to assess long-term outcome after transplantation of HOPE-treated donor livers based on real-world data (i.e., IDEAL-D stage 4). METHODS: In this international, multicentre, observational cohort study, we collected data from adult recipients of a HOPE-treated liver transplanted between January 2012 and December 2021. Analyses were stratified for brain-dead (DBD) and circulatory-dead (DCD) donor livers, sub-divided by their respective risk categories. The primary outcome was death-censored graft survival. Secondary outcomes included the incidence of primary non-function (PNF) and ischemic cholangiopathy (IC). RESULTS: We report on 1202 liver transplantations (64% DBD) performed at 22 European centres. For DBD, a total number of 99 benchmark (8%), 176 standard (15%), and 493 extended-criteria (41%) cases were included. For DCD, 117 transplants were classified as low-risk (10%), 186 as high-risk (16%), and 131 as futile (11%), with significant risk profile variations among centres. Actuarial 1-, 3-, and 5-year death-censored graft survival for DBD and DCD was 95%, 92%, and 91%, vs. 92%, 87%, and 81%, respectively (logrank p=0.003). Within DBD and DCD-strata, death-censored graft survival was similar among risk groups (logrank p=0.26, p=0.99). Graft loss due to PNF or IC was 2.3% and 0.4% (DBD), and 5% and 4.1% (DCD). CONCLUSIONS: This study shows excellent 5-year survival after transplantation of HOPE-treated DBD and DCD livers with low rates of graft loss due to PNF or IC, irrespective of their individual risk profile. HOPE-treatment has now reached IDEAL-D stage 4, which further supports the implementation of HOPE in routine clinical practice. IMPACT AND IMPLICATIONS: This study demonstrates the excellent long-term performance of HOPE-treatment of DCD and DBD liver grafts irrespective of their individual risk profile in a real-world setting, outside the evaluation of randomized controlled trials. While previous studies have established safety, feasibility, and efficacy against the current standard, according to the IDEAL-D evaluation framework, HOPE-treatment has now reached the final IDEAL-D Stage 4, which further supports the implementation of HOPE in routine clinical practice. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT05520320.

Cornerstones and divergencies in the implementation and use of liver hypertrophy techniques: results from a nationwide survey for the set-up of the prospective registry.

BACKGROUND: The aim of this national survey on liver hypertrophy techniques was to track the trends of their use and implementation in Italy and to detect analogies and heterogeneities among centers. METHODS: In December 2022, Italian centers with liver resection activity were specifically contacted and asked to fill an online questionnaire composed of 6 sections including a total of 51 questions. RESULTS: 46 Italian centers filled the questionnaire. The proportion of major/total number of liver resections was 27% and the use of hypertrophy techniques was required in 6,2% of cases. The most frequent reason of drop out was disease progression in 58.5% of cases. Most frequently used techniques were PVE and ALPPS with an increasing use of hepatic venous deprivation (HVD). Heterogeneous answers were provided regarding the cutoff values to indicate the need for hypertrophy techniques. Criteria to allocate a patient to different hypertrophy techniques are not standardized. CONCLUSIONS: The use of hypertrophy techniques is deep-rooted in Italy, documenting the established value of their role in improving resectability rate. While an evolution of techniques is detectable, still significant heterogeneity is perceived in terms of cutoff values, indications and managing protocols.

Combined transarterial chemoembolization and thermal ablation in candidates to liver transplantation with hepatocellular carcinoma: pathological findings and post-transplant outcome.

OBJECTIVES: Evaluating the pathological response and the survival outcomes of combined thermal ablation (TA) and transarterial chemoembolization (TACE) as a bridge or downstaging for liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) > 3 cm. MATERIALS AND METHODS: A retrospective review encompassed 36 consecutive patients who underwent combined TA-TACE as bridging or downstaging before LT. Primary objectives included necrosis of the target lesion at explant pathology, post-LT overall survival (OS) and post-LT recurrence-free survival (RFS). For OS and RFS, a comparison with 170 patients subjected to TA alone for nodules <3 cm in size was also made. RESULTS: Out of the 36 patients, 63.9% underwent TA-TACE as bridging, while 36.1% required downstaging. The average node size was 4.25 cm. All cases were discussed in a multidisciplinary tumor board to assess the best treatment for each patient. Half received radiofrequency (RF), and the other half underwent microwave (MW). All nodes underwent drug-eluting beads (DEB) TACE with epirubicin. The mean necrosis percentage was 65.9% in the RF+TACE group and 83.3% in the MW+TACE group (p-value = 0.099). OS was 100% at 1 year, 100% at 3 years and 94.7% at 5 years. RFS was 97.2% at 1 year, 94.4% at 3 years and 90% at 5 years. Despite the different sizes of the lesions, OS and RFS did not show significant differences with the cohort of patients subjected to TA alone. CONCLUSIONS: The study highlights the effectiveness of combined TA-TACE for HCC>3 cm, particularly for bridging and downstaging to LT, achieving OS and RFS rates significantly exceeding 80% at 1, 3 and 5 years.

Liver transplantation for tumor entities.

PURPOSE OF REVIEW: Tumor entities represent an increasing indication for liver transplantation (LT). This review addresses the most contentious indications of LT in transplant oncology. RECENT FINDINGS: Patient selection based on tumor biology in LT for colorectal cancer liver metastases (CRLM) demonstrated promising long-term outcomes and preserved quality of life despite high recurrence rates. In selected cases, LT for intrahepatic cholangiocarcinoma (iCCA) is feasible, with acceptable survival even in high-burden cases responsive to chemotherapy. LT following a strict neoadjuvant protocol for perihilar cholangiocarcinoma (pCCA) resulted in long-term outcomes consistently surpassing benchmark values, and potentially outperforming liver resection. SUMMARY: While preliminary results are promising, prospective trials are crucial to define applications in routine clinical practice. Molecular profiling and targeted therapies pave the way for personalized approaches, requiring evolving allocation systems for equitable LT access.

Portal vein thrombosis and liver transplantation: management, matching, and outcomes. A retrospective multicenter cohort study.

BACKGROUND AND AIMS: Besides the increased risk of perioperative morbidity, graft failure, and mortality, the majority of PVT are diagnosed at liver transplantation (LT). Improving preoperative management and patient selection may lead to better short-term and long-term outcomes and reduce the risk of a futile LT. The authors aimed to identify predictors of adverse outcomes after LT in patients with nonmalignant portal vein thrombosis (PVT) and improve donor to recipient matching by analyzing the results of the Italian cohort of LT recipients. METHODS: Adult patients who underwent LT in Italy between January 2000 and February 2020 diagnosed with PVT pre-LT or at time of LT were considered eligible for inclusion. Based on a survey encompassing all 26 surgeons participating in the study, a binary composite outcome was defined. Patients were classified as having the composite event if at least one of these conditions occurred: operative time more than 600 min, estimated blood loss greater than 5000 ml, more than 20 ICU days, 90 days mortality, 90 days retransplant. RESULTS: Seven hundred fourteen patients were screened and 698 met the inclusion criteria. The analysis reports the results of 568 patients that fulfilled the criteria to enter the composite outcome analysis.Overall, 156 patients (27.5%) developed the composite outcome. PVT stage 3/4 at transplant and need for any surgical correction of PVT are independent predictors of the composite outcome occurrence. When stratified by PVT grade, overall survival at 1-year ranges from 89.0% with PVT grade 0/1 to 67.4% in patients with PVT grade 3/4 at LT ( P <0.001). Nevertheless, patients with severe PVT can improve their survival when identified risk factors are not present. CONCLUSIONS: Potential LT candidates affected by PVT have a benefit from LT that should be adequately balanced on liver function and type of inflow reconstruction needed to mitigate the incidence of adverse events. Nonetheless, the absence of specific risk factors may improve the outcomes even in patients with PVT grades 3-4.

Recipient hepatectomy technique may affect oncological outcomes of liver transplantation for hepatocellular carcinoma.

To date, caval sparing (CS) and total caval replacement (TCR) for recipient hepatectomy in liver transplantation (LT) have been compared only in terms of surgical morbidity. Nonetheless, the CS technique is inherently associated with an increased manipulation of the native liver and later exclusion of the venous outflow, which may increase the risk of intraoperative shedding of tumor cells when LT is performed for HCC. A multicenter, retrospective study was performed to assess the impact of recipient hepatectomy (CS vs. TCR) on the risk of posttransplant HCC recurrence among 16 European transplant centers that used either TCR or CS recipient hepatectomy as an elective protocol technique. Exclusion criteria comprised cases of non-center-protocol recipient hepatectomy technique, living-donor LT, HCC diagnosis suspected on preoperative imaging but not confirmed at the pathological examination of the explanted liver, HCC in close contact with the IVC, and previous liver resection for HCC. In 2420 patients, CS and TCR approaches were used in 1452 (60%) and 968 (40%) cases, respectively. Group adjustment with inverse probability weighting was performed for high-volume center, recipient age, alcohol abuse, viral hepatitis, Child-Pugh class C, Model for End-Stage Liver Disease score, cold ischemia time, clinical HCC stage within Milan criteria, pre-LT downstaging/bridging therapies, pre-LT alphafetoprotein serum levels, number and size of tumor nodules, microvascular invasion, and complete necrosis of all tumor nodules (matched cohort, TCR, n = 938; CS, n = 935). In a multivariate cause-specific hazard model, CS was associated with a higher risk of HCC recurrence (HR: 1.536, p = 0.007). In conclusion, TCR recipient hepatectomy, compared to the CS approach, may be associated with some protective effect against post-LT tumor recurrence.

Improved assessment of donor liver steatosis using Banff consensus recommendations and deep learning algorithms.

BACKGROUND & AIMS: The Banff Liver Working Group recently published consensus recommendations for steatosis assessment in donor liver biopsy, but few studies reported their use and no automated deep-learning algorithms based on the proposed criteria have been developed so far. We evaluated Banff recommendations on a large monocentric series of donor liver needle biopsies by comparing pathologists' scores with those generated by convolutional neural networks (CNNs) we specifically developed for automated steatosis assessment. METHODS: We retrospectively retrieved 292 allograft liver needle biopsies collected between January 2016 and January 2020 and performed steatosis assessment using a former intra-institution method (pre-Banff method) and the newly introduced Banff recommendations. Scores provided by pathologists and CNN models were then compared, and the degree of agreement was measured with the intraclass correlation coefficient (ICC). RESULTS: Regarding the pre-Banff method, poor agreement was observed between the pathologist and CNN models for small droplet macrovesicular steatosis (ICC: 0.38), large droplet macrovesicular steatosis (ICC: 0.08), and the final combined score (ICC: 0.16) evaluation, but none of these reached statistically significance. Interestingly, significantly improved agreement was observed using the Banff approach: ICC was 0.93 for the low-power score (p <0.001), 0.89 for the high-power score (p <0.001), and 0.93 for the final score (p <0.001). Comparing the pre-Banff method with the Banff approach on the same biopsy, pathologist and CNN model assessment showed a mean (±SD) percentage of discrepancy of 26.89 (±22.16) and 1.20 (±5.58), respectively. CONCLUSIONS: Our findings support the use of Banff recommendations in daily practice and highlight the need for a granular analysis of their effect on liver transplantation outcomes. IMPACT AND IMPLICATIONS: We developed and validated the first automated deep-learning algorithms for standardized steatosis assessment based on the Banff Liver Working Group consensus recommendations. Our algorithm provides an unbiased automated evaluation of steatosis, which will lay the groundwork for granular analysis of steatosis's short- and long-term effects on organ viability, enabling the identification of clinically relevant steatosis cut-offs for donor organ acceptance. Implementing our algorithm in daily clinical practice will allow for a more efficient and safe allocation of donor organs, improving the post-transplant outcomes of patients.

Liver transplantation with uncontrolled versus controlled DCD donors using normothermic regional perfusion and ex-situ machine perfusion.

In Italy, 20 minutes of continuous, flat-line electrocardiogram are required for death declaration, which significantly increases the risks of donation after circulatory death (DCD) LT. Despite prolonged warm ischemia time, Italian centers reported good outcomes in controlled donation after circulatory death LT by combining normothermic regional and end-ischemic machine perfusion. However, data on uncontrolled DCD (uDCD) LT performed by this approach are lacking. This was a multicenter, retrospective study performed at 3 large-volume centers comparing clinical outcomes of uncontrolled versus controlled DCD LT. The aim of the study was to assess outcomes of sequential normothermic regional perfusion and end-ischemic machine perfusion in uncontrolled DCD liver transplantation (LT). Of 153 DCD donors evaluated during the study period, 40 uDCD and 59 donation after circulatory death grafts were transplanted (utilization rate 52% vs. 78%, p = 0.004). Recipients of uDCD grafts had higher MEAF (4.9 vs. 3.5, p < 0.001) and CCI scores at discharge (24.4 vs. 8.7, p = 0.026), longer ICU stay (5 vs. 4 d, p = 0.047), and a trend toward more severe AKI. At multivariate analysis, 90-day graft loss was associated with recipient BMI and lactate downtrend during normothermic regional perfusion. One-year graft survival was lower in uDCD (75% vs. 90%, p = 0.007) but became comparable when non-liver-related graft losses were treated as censors (77% vs. 90%, p = 0.100). The incidence of ischemic cholangiopathy was 10% in uDCD versus 3% in donation after circulatory death, p = 0.356. uDCD LT with prolonged warm ischemia is feasible by the sequential use of normothermic regional perfusion and end-ischemic machine perfusion. Proper donor and recipient selection are key to achieving good outcomes in this setting.

Tailoring allocation policies and improving access to paediatric liver transplantation over a 16-year period.

BACKGROUND & AIMS: Mortality on the paediatric liver transplantation (pLT) waiting list (WL) is still an issue. We analysed the Italian pLT WL to evaluate the intention-to-treat (ITT) success rate and to identify factors influencing success. METHODS: All children (<18 years) listed for pLT in Italy between 2002-2018 were included (Era 1 [2002-2007]: centre-based allocation; Era 2 [2008-2014]: national allocation; Era 3 [2015-2018]: national allocation+mandatory-split policy). RESULTS: A total of 1,424 patients (median age: 2.0 [IQR 1.0-9.0] years; median weight: 12.0 kg [IQR 7-27]) were listed for pLT. Median WL time was 2 days (IQR 1-5) for Status 1 and 44 days (IQR 15-120) for non-Status 1 patients; 1,302 children (91.4%) were transplanted (67.3% with split grafts), while 50 children (3.5%) dropped off the WL (2.5% death, 1.0% clinical deterioration). Predictive factors for receiving LT included Status 1 (hazard ratio [HR] 1.66, p = 0.001), Status 1B (HR 1.96, p = 0.016), Status 2A (HR 2.15, p = 0.024) and each 1-point increase in PELD/MELD score. Children with recipient's weight >25 kg, blood group O or awaiting pLT combined with other organs had less chance of being transplanted. ITT patient survival rates were 90.5% at 1 year and 87.5% at 5 years, remaining stable across eras. Risk factors for ITT survival were re-transplantation (HR 5.83, p <0.001), Status 1 (HR 2.28, p = 0.006), Status 1B (HR 2.90, p = 0.014), Status 2A (HR 9.12, p <0.001), recipient weight <6 kg (HR 4.53, p <0.001) and low-volume activity (HR 4.38, p = 0.001). CONCLUSIONS: In Italy, continuous adaption of paediatric organ allocation policies via the introduction of national allocation, paediatric prioritisation rules and a mandatory-split policy have helped maximise the use of donors for paediatric candidates and to minimise WL mortality without compromising outcomes. IMPACT AND IMPLICATIONS: Globally, paediatric liver transplant candidates still suffer from high mortality. Over recent decades, the continuous adaption of organ allocation policies in Italy has led to excellent outcomes for children awaiting liver transplantation. The mortality rate of paediatric liver transplant candidates has been minimised to almost zero, mainly using grafts from deceased donors. Paediatric prioritisation rules, national organ exchange organisation and a mandatory-split liver policy have resulted in a unique allocation model for paediatric liver transplant candidates and represent a landmark for the paediatric transplant community.

Organ Repair and Regeneration During Ex Situ Dynamic Preservation: The Future is Nano.

Organ preservation and assessment with machine perfusion (MP) has provided transplant physicians with the ability to evaluate and select grafts suitable for transplantation. Nevertheless, the discard of organs considered too damaged still sustains the imbalance between donor organs supply and demands. Therefore, there is the pressing clinical need for strategies to repair and/or regenerate organs before transplantation, and MP is uniquely positioned to satisfy this need. The systemic administration of mesenchymal stromal cells (MSC) was shown to reduce ischemia-reperfusion injury in pre-clinical organ transplant models but could not be reproduced in clinical transplantation, largely because of inefficient cell delivery. The administration of MSC during MP is one strategy that recently gained much attention as an alternative delivery method to target MSC directly to the donor organ. However, careful reinterpretation of preliminary results reveals that this approach is equally limited by a suboptimal delivery of short-lived MSC to the target organ. In contrast, the use of MSC secretome and/or extracellular vesicles therapy during MP seems to be more efficient in harnessing MSC properties during MP. In this mini review we speculate on the future of the novel niche of ex situ organ repair and regeneration before transplantation.

Extracellular Vesicles in Liver Transplantation: Current Evidence and Future Challenges.

Extracellular vesicles (EVs) are emerging as a promising field of research in liver disease. EVs are small, membrane-bound vesicles that contain various bioactive molecules, such as proteins, lipids, and nucleic acids and are involved in intercellular communication. They have been implicated in numerous physiological and pathological processes, including immune modulation and tissue repair, which make their use appealing in liver transplantation (LT). This review summarizes the current state of knowledge regarding the role of EVs in LT, including their potential use as biomarkers and therapeutic agents and their role in graft rejection. By providing a comprehensive insight into this emerging topic, this research lays the groundwork for the potential application of EVs in LT.

Favorable experience of transplant strategy including liver grafts from COVID-19 donors: One-year follow-up results.

BACKGROUND: Since November 2020, Italy was the first country to carry out a protocol and use liver from COVID-19 donors. We aimed to evaluate the medium-term outcome of patients who underwent liver transplant (LT) with those grafts. METHODS: We consecutively enrolled 283 patients who underwent first LT from November 2020 to December 2022 in our Center (follow-up 468 days). Twenty-five of 283 (8.8%, study population) received a graft from donors with previous (4%) or active (96%) SARS-CoV-2 infection, and 258/283 (91.2%, control group) received a graft from COVID-19-negative donors. SARS-CoV-2-RNA was tested on graft tissue of COVID-19 donors and their recipients underwent weekly evaluation of SARS-CoV-2-RNA in nasal swabs for the first month after LT. RESULTS: One-year and 2-year patient survival was 88.5% and 88.5% in study group versus 94.5% and 93.5% in control group, respectively (p = .531). In study population there was no evidence of donor-recipient virus transmission, but three (12%) patients (vs. 7 [2.7%] of control group, p = .048) developed hepatic artery thrombosis (HAT): they were SARS-CoV-2-RNA negative at LT and 1/3 grafts tested SARS-CoV-2-RNA positive on liver tissue. COVID-19 donor was independently associated with HAT (odds ratio (OR) = 4.85, 95% confidence interval (CI) 1.10-19.15; p = .037). By comparing study population with control group, acute rejection and biliary complication rates were not significantly different (16% vs. 8.1%, p = .26; 16% vs. 16.3% p = .99, respectively). CONCLUSIONS: Our 1-year results of transplant strategy including liver grafts from COVID-19 donors were favorable. HAT was the only complication with significantly higher rate in patients transplanted with COVID-19 donors compared with control group.

Viability assessment of livers donated after circulatory determination of death during normothermic regional perfusion.

BACKGROUND: Abdominal normothermic regional perfusion (A-NRP) allows in-situ reperfusion and recovery of abdominal organs metabolism in donors after circulatory death (DCD). Besides improving liver transplantation outcomes, liver injury and function can be assessed during A-NRP. METHODS: To refine liver viability assessment during A-NRP, prospectively collected data of controlled DCD donors managed at our Institution between October 2019 and May 2022 were retrospectively analyzed. Baseline characteristics, procedural variables and A-NRP parameters of donors whose liver was successfully transplanted were compared to those of donors whose liver was discarded. RESULTS: Twenty-seven donors were included and in 20 (74%) the liver was accepted (positive outcome). No differences between study groups were observed concerning baseline characteristics and warm ischemia times (WIT). Initial lactate levels were positively correlated with functional WIT (r2 = 0.4, p = 0.04), whereas transaminase levels were not. Blood flow during A-NRP was comparable, whereas oxygen consumption (VO2 ) was significantly higher in the positive outcome group after 1 h. Time courses of lactate, AST and ALT were significantly different between study groups (p < 0.001). Donors whose liver was accepted showed faster lactate clearance, a difference which was amplified by normalizing lactate clearance to oxygen delivery (DO2 ) and VO2 . Lactate clearance was correlated to transaminase levels and DO2 -normalized lactate clearance was the parameter best discriminating between study groups. CONCLUSIONS: DO2 -normalized lactate clearance may represent an element of liver viability assessment during A-NRP.