Clinical prognosticators and targets in the immune microenvironment of intrahepatic cholangiocarcinoma.

Background: Intrahepatic cholangiocarcinoma (ICC) is a disease with poor prognosis and limited therapeutic options. We investigated the tumor immune microenvironment (TIME) to identify predictors of disease outcome and to explore targets for therapeutic modulation. Methods: Liver tissue samples were collected during 2008-2019 from patients (n = 139) diagnosed with ICC who underwent curative intent surgery without neoadjuvant chemotherapy. Samples from the discovery cohort (n = 86) were immunohistochemically analyzed on tissue microarrays (TMAs) for the expression of CD68, CD3, CD4, CD8, Foxp3, PD-L1, STAT1, and p-STAT1 in tumor core and stroma areas. Results were digitally analyzed using QuPath software and correlated with clinicopathological characteristics. For validation of TIME-related biomarkers, we performed multiplex imaging mass cytometry (IMC) in a validation cohort (n = 53). Results: CD68+ cells were the predominant immune cell type in the TIME of ICC. CD4+high T cell density correlated with better overall survival (OS). Prediction modeling together with validation cohort confirmed relevance of CD4+ cells, PD-L1 expression by immune cells in the stroma and N-stage on overall disease outcome. In turn, IMC analyses revealed that silent CD3+CD4+ clusters inversely impacted survival. Among annotated immune cell clusters, PD-L1 was most relevantly expressed by CD4+FoxP3+ cells. A subset of tumors with high density of immune cells ("hot" cluster) correlated with PD-L1 expression and could identify a group of candidates for immune checkpoint inhibition (ICI). Ultimately, higher levels of STAT1 expression were associated with higher lymphocyte infiltration and PD-L1 expression. Conclusions: These results highlight the importance of CD4+ T cells in immune response against ICC. Secondly, a subset of tumors with "hot" TIME represents potential candidates for ICI, while stimulation of STAT1 pathway could be a potential target to turn "cold" into "hot" TIME in ICC.

The tumor immune microenvironment (TIME) plays a critical role in the immune response In many cancers, including intrahepatic cholangiocarcinoma (ICC). Molecular subtyping of the ICC microenvironment already revealed inter-tumoral heterogeneity with variant profiles of immune cell infiltrates. A recent study created an in-depth immune cell atlas of the TIME in biliary tract cancers and could demonstrate the relevance of specific immune cell subpopulations on patient outcome. We are able to provide a distinctive characterization of TIME, separating tumor epithelial- and stroma areas, in a large and representative ICC cohort using digitalized image analysis on tissue microarrays (TMA) as well as multiplex imaging mass cytometry (IMC). The study was designed for identification of immune cell prognosticators allocating institutional ICC patients into a discovery (2008­15) and a validation (2010­19) cohort. Immune cell subpopulations were correlated with clinicopathological characteristics and patient outcome. Our results highlight: i. The important role of CD4+ T cell infiltration in ICC patients; ii. ICC tumors with high density of immune cells associated with PD-L1 expression identifies a subset of patients with variant tumor biology; iii. Stimulation of STAT1 pathway may be a relevant target to turn "cold" into "hot" tumors.

Multimodal management of ectopic hepatic pregnancy: a systematic review of the literature.

PURPOSE: Ectopic pregnancies with implantation in the upper abdomen are exceptionally rare. Here we provide a systematic review of hepatic ectopic pregnancies and the corresponding management strategies. Furthermore, this report details a case of ectopic hepatic pregnancy, successfully treated with primary methotrexate (MTX) followed by a two-staged robotic-assisted resection. METHODS: Two independent investigators performed a systematic review using the online search engine PubMed and MEDLINE database. The search utilized the following terms: 'Hepatic Ectopic Pregnancy,' 'Hepatic Extrauterine Pregnancy,' 'Hepatic Abdominal Pregnancy,' and 'Ectopic Liver Pregnancy.' Cross-referencing was employed to identify possible additional publications. FINDINGS: Forty-seven case reports on hepatic pregnancies were identified. Of these, 40 provided manuscripts in the English language. Most patients with hepatic pregnancy presented with mild to moderate abdominal pain, while only a minority exhibited signs of hemodynamically relevant intraperitoneal hemorrhage. Most cases were managed through open surgical removal, although in recent years, there has been an increase in laparoscopically managed cases. Conservative approaches using methotrexate are seldom employed. CONCLUSION: Hepatic pregnancies present a rare and challenging clinical scenario. Until now, these cases have usually been treated primarily with open explorative surgery. As reported in this case, primary conservative treatment approaches with MTX before surgery hold promise as a strategy to reduce surgery-related bleeding and morbidity, particularly for asymptomatic or oligosymptomatic patients.

Is interval chemotherapy safe and does it improve the outcome of patients with colorectal liver metastases undergoing multimodal two-stage hepatectomy? - A systematic literature review.

BACKGROUND: Multimodal two-stage hepatectomy (mTSH) is used in patients with bilobar colorectal liver metastases (CRLM) that cannot be treated with one surgical procedure due to insufficient future liver remnant. Interval chemotherapy has been proposed to improve disease control in CRLM patients undergoing mTSH. We here present a narrative review of clinical studies on mTSH including the use of interval chemotherapy in patients with CRLM. METHODS: A systematic literature search of the PubMed databases as well as the ClinicalTrials.gov registry was performed. RESULTS: The use of interval chemotherapy during mTSH was reported in 23 studies and applied in 595 out of 1,461 patients with CRLM. Two studies report on the actual effects of this treatment, one study describes a trend towards improved disease progression rate. No serious adverse events caused by interval chemotherapy were observed. There is currently no randomized clinical trial investigating the efficacy and safety of interval chemotherapy during mTSH. CONCLUSION: The currently available data indicate that interval chemotherapy does neither impair liver hypertrophy during mTSH nor cause procedure-associated complications in patients with CRLM. Results from randomized clinical trials on the potential positive effect on disease control are not yet available.

Emergency surgery influences oncological outcome in small intestinal neuroendocrine tumors.

BACKGROUND AND AIMS: Patients with small intestinal neuroendocrine tumors (siNETs) frequently present emergently due to bowel ischemia or bowel obstruction. The influence of emergency surgery on the prognosis of siNET remains controversial. The aim of this study was to investigate the association between type of presentation (emergency/elective) and oncological outcome. METHODS: Clinicopathological data of patients who underwent bowel resection and were treated due to siNET at the Charité - Universitätsmedizin Berlin, Germany were analyzed retrospectively. RESULTS: A total of 165 patients underwent bowel resection for siNET. Of these, 22.4% (n = 37) were emergency and 77.6% (n = 128) were elective procedures. A preoperative known diagnosis was less common in patients with emergency surgery (48.6% vs 85.2%; p < 0.001) and complete resections of all tumor manifestations were performed less often (32.4% vs 50.8%; p = 0.049), while more completion operations had to be performed (24.3% vs 11.1%; p = 0.049). Overall survival (OS) and progression-free survival (PFS) of emergently operated patients were reduced (5-year OS: 85.2% vs 89.5% (p = 0.023); 5-year PFS: 26.7% versus 52.5% (p = 0.018)). In addition, emergency surgery was negatively associated with OS after multivariable regression analysis. CONCLUSION: Emergency surgery in siNET patients is associated with adverse oncological outcomes including shorter OS and PFS. Prevention of emergency conditions should be emphasized in advanced disease.

Outcome-Orientated Organ Allocation-A Composite Risk Model for Pancreas Graft Evaluation and Acceptance.

Background: Pancreas transplantation (PTX) remains the most effective treatment to prevent long-term complications and provide consistent euglycemia in patients with endocrine pancreatic insufficiency, mainly in type I diabetic patients. Considering early graft loss (EGL) and the perioperative complication rate, an optimal risk stratification based on donor risk factors is paramount. Methods: In our single-center study, we retrospectively assessed the risk factors for EGL and reduced graft survival in 97 PTXs (82 simultaneous pancreas and kidney [SPK], 11 pancreases transplanted after kidney [PAK] and 4 pancreases transplanted alone [PTA]) between 2010 and 2021. By statistically analyzing the incorporation of different donor risk factors using the Kaplan-Meier method and a log-rank test, we introduced a composite risk model for the evaluation of offered pancreas grafts. Results: The overall EGL rate was 6.5%. In the univariate analysis of donor characteristics, age > 45 years, BMI > 25 kg/m2, lipase > 60 U/L, cerebrovascular accident (CVA) as the cause of death, mechanical cardiopulmonary resuscitation (mCPR), cold ischemia time (CIT) > 600 min and retrieval by another center were identified as potential risk factors; however, they lacked statistical significance. In a multivariate model, age > 45 years (HR 2.05, p = 0.355), BMI > 25 kg/m2 (HR 3.18, p = 0.051), lipase > 60 U/L (HR 2.32, p = 0.148), mCPR (HR 8.62, p < 0.0001) and CIT > 600 min (HR 1.89, p = 0.142) had the greatest impact on pancreas graft survival. We subsumed these factors in a composite risk model. The combination of three risk factors increased the rate of EGL significantly (p = 0.003). Comparing the pancreas graft survival curves for ≥3 risk factors to <3 risk factors in a Kaplan-Meier model revealed significant inferiority in the pancreas graft survival rate (p = 0.029). Conclusions: When evaluating a potential donor organ, grafts with a combination of three or more risk factors should only be accepted after careful consideration to reduce the risk of EGL and to significantly improve outcomes after PTX.

Morbidity and Mortality after Cytoreductive Surgery and HIPEC in a National Reference Center: A Six-Year Experience under Independent Evaluation.

Introduction: Cytoreductive surgery (CRS) coupled with hyperthermic intraperitoneal chemotherapy (HIPEC) is a potentially curative approach to peritoneal disease (PD) and corresponds to the needs of patients with dire survival rates. However, the oncological community remains cautious toward this procedure because of its significant morbidity and mortality rates. This evolving evidence around CRS and HIPEC and its impact suggests a need for more standardized procedures in existing centers. Because of its complexity and potential for high morbidity and mortality, critical observation of our center's complication rates using complication management documentation tools were crucial to further develop our standard operating procedures (SOP) and maximize patient safety. Methods: Our prospectively maintained institutional database was queried to identify all patients who underwent CRS and HIPEC and had a filled-out quality management (QM) and complication management documentation tool at discharge at the surgical department of the Charité-Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany, between January 2018 and December 2023. Results: A total of 155 patients had a surgical and/or medical complication recorded. In total, 305 surgeries were surveyed. Some patients had more than one postoperative complication; hence, 344 events in 50 categories were recorded, of which 267 were graded 3a or higher in 92 patients. The most common medical complications were of pulmonary and renal origin. On the surgical side, surgical site infections (SSI) were most common. The incidence of anastomotic leakage (AL) was 5% (n = 8), with no events between 2021 and the present. Patients with longer surgery duration times were at higher risk for developing postoperative complications. Conclusions: Major abdominal surgeries like CRS and HIPEC are associated with significant patient morbidity despite achieving optimal oncological outcomes. Postoperative complications are managed through strict surveillance and transparency, particularly in our large reference centers, to minimize patient risk. Quality management programs in our department have successfully maintained high standards of care without compromising patient safety.

Enhancing Preoperative Outcome Prediction: A Comparative Retrospective Case-Control Study on Machine Learning versus the International Esodata Study Group Risk Model for Predicting 90-Day Mortality in Oncologic Esophagectomy.

Risk prediction prior to oncologic esophagectomy is crucial for assisting surgeons and patients in their joint informed decision making. Recently, a new risk prediction model for 90-day mortality after esophagectomy using the International Esodata Study Group (IESG) database was proposed, allowing for the preoperative assignment of patients into different risk categories. However, given the non-linear dependencies between patient- and tumor-related risk factors contributing to cumulative surgical risk, machine learning (ML) may evolve as a novel and more integrated approach for mortality prediction. We evaluated the IESG risk model and compared its performance to ML models. Multiple classifiers were trained and validated on 552 patients from two independent centers undergoing oncologic esophagectomies. The discrimination performance of each model was assessed utilizing the area under the receiver operating characteristics curve (AUROC), the area under the precision-recall curve (AUPRC), and the Matthews correlation coefficient (MCC). The 90-day mortality rate was 5.8%. We found that IESG categorization allowed for adequate group-based risk prediction. However, ML models provided better discrimination performance, reaching superior AUROCs (0.64 [0.63-0.65] vs. 0.44 [0.32-0.56]), AUPRCs (0.25 [0.24-0.27] vs. 0.11 [0.05-0.21]), and MCCs (0.27 ([0.25-0.28] vs. 0.15 [0.03-0.27]). Conclusively, ML shows promising potential to identify patients at risk prior to surgery, surpassing conventional statistics. Still, larger datasets are needed to achieve higher discrimination performances for large-scale clinical implementation in the future.

Propensity Score-matched Analysis Comparing Robotic Versus Laparoscopic Minor Liver Resections of the Anterolateral Segments: an International Multi-center Study of 10,517 Cases.

OBJECTIVE: To compare the outcomes of robotic minor liver resections (RMLR) versus laparoscopic (L) MLR of the anterolateral segments. BACKGROUND: Robotic liver surgery has been gaining prominence over the years with increasing usage for a myriad of hepatic resections. Robotic liver resections(RLR) has demonstrated non-inferiority to laparoscopic(L)LR while illustrating advantages over conventional laparoscopy especially for technically difficult and major LR. However, the advantage of RMLR for the anterolateral(AL) (segments II, III, IVb, V and VI) segments, has not been clearly demonstrated. METHODS: Between 2008 to 2022, 15,356 of 29,861 patients from 68 international centres underwent robotic(R) or laparoscopic minor liver resections (LMLR) for the AL segments Propensity score matching (PSM) analysis was performed for matched analysis. RESULTS: 10,517 patients met the study criteria of which 1,481 underwent RMLR and 9,036 underwent LMLR. A PSM cohort of 1,401 patients in each group were identified for analysis. Compared to the LMLR cohort, the RMLR cohort demonstrated significantly lower median blood loss (75ml vs. 100ml, P<0.001), decreased blood transfusion (3.1% vs. 5.4%, P=0.003), lower incidence of major morbidity (2.5% vs. 4.6%, P=0.004), lower proportion of open conversion (1.2% vs. 4.5%, P<0.001), shorter post operative stay (4 days vs. 5 days, P<0.001), but higher rate of 30-day readmission (3.5% vs. 2.1%, P=0.042). These results were then validated by a 1:2 PSM analysis. In the subset analysis for 3,614 patients with cirrhosis, RMLR showed lower median blood loss, decreased blood transfusion, lower open conversion and shorter post operative stay than LMLR. CONCLUSION: RMLR demonstrated statistically significant advantages over LMLR even for resections in the AL segments although most of the observed clinical differences were minimal.

Generation of an induced pluripotent stem cell (iPSC) line (EXSURGi001-A) from a patient homozygous for the p.Ala165Thr mutation in the MTARC1 gene.

Metabolic dysfunction-associated fatty liver disease (MAFLD), the leading cause of end-stage liver disease in developed countries, is expected to increase over the next decade. Characterized by hepatic steatosis, MAFLD is commonly studied in animal models. Here, we generated a human induced pluripotent stem cell (iPSC) line from a patient homozygous of the protective MTARC1 gene variant rs2642438:A. This line displays a normal karyotype and typical pluripotent stem cell morphology and can differentiate into all three germ layers in vitro.

Viscoelastic properties of colorectal liver metastases reflect tumour cell viability.

BACKGROUND: Colorectal cancer is the third most common tumour entity in the world and up to 50% of the patients develop liver metastases (CRLM) within five years. To improve and personalize therapeutic strategies, new diagnostic tools are urgently needed. For instance, biomechanical tumour properties measured by magnetic resonance elastography (MRE) could be implemented as such a diagnostic tool. We postulate that ex vivo MRE combined with histological and radiological evaluation of CRLM could provide biomechanics-based diagnostic markers for cell viability in tumours. METHODS: 34 CRLM specimens from patients who had undergone hepatic resection were studied using ex vivo MRE in a frequency range from 500 Hz to 5300 Hz with increments of 400 Hz. Single frequency evaluation of shear wave speed and wave penetration rate as proxies for stiffness and viscosity was performed, along with rheological model fitting based on the spring-pot model and powerlaw exponent α, ranging between 0 (complete solid behaviour) and 1 (complete fluid behaviour). For histological analysis, samples were stained with H&E and categorized according to the degree of regression. Quantitative histologic analysis was performed to analyse nucleus size, aspect ratio, and density. Radiological response was assessed according to RECIST-criteria. RESULTS: Five samples showed major response to chemotherapy, six samples partial response and 23 samples no response. For higher frequencies (> 2100 Hz), shear wave speed correlated significantly with the degree of regression (p ≤ 0.05) indicating stiffer properties with less viable tumour cells. Correspondingly, rheological analysis of α revealed more elastic-solid tissue properties at low cell viability and major response (α = 0.43 IQR 0.36, 0.47) than at higher cell viability and no response (α = 0.51 IQR 0.48, 0.55; p = 0.03). Quantitative histological analysis showed a decreased nuclear area and density as well as a higher nuclear aspect ratio in patients with major response to treatment compared to patients with no response (all p < 0.05). DISCUSSION: Our results suggest that MRE could be useful in the characterization of biomechanical property changes associated with cell viability in CRLM. In the future, MRE could be applied in clinical diagnosis to support individually tailored therapy plans for patients with CRLM.

Multinational Analysis of Marginal Liver Grafts Based on the Eurotransplant Extended Donor Criteria.

OBJECTIVE: To evaluate the outcome of marginal liver grafts based on the Eurotransplant extended donor criteria (ECD) criteria. SUMMARY BACKGROUND DATA: Eurotransplant uses a broad definition of ECD criteria (age >65 years, steatosis >40%, BMI >30 kg/m2, ICU stay >7 days, DCD, and certain laboratory parameters) for allocating organs to recipients who have consented to marginal grafts. Historically, marginal liver grafts were associated with increased rates of dysfunction. METHODS: Retrospective cohort analysis using the German Transplant Registry (GTR) and the US Scientific Registry of Transplant Recipients (SRTR) from 2006-2016. Results were validated with recent SRTR data (2017-2022). Donors were classified according to the Eurotransplant ECD criteria, DCD was excluded. Data were analyzed with cut-off prediction, binomial logistic regression, and multivariate Cox regression. RESULTS: The study analyzed 92,330 deceased brain-dead donors (87% SRTR) and 70,374 transplants (87% SRTR) in adult recipients. Predominant ECD factors were donor age in Germany (30%) and BMI in the US (28%). Except for donor age, grafts meeting ECD criteria were not associated with impaired 1- or 3-year survival. Cut-offs had little to no predictive value for 30-day graft survival (AUROC 0.49 - 0.52) and were nominally higher for age (72 vs. 65 years) in Germany as compared to those defined by current Eurotransplant criteria. CONCLUSIONS: The outcome of transplanted grafts from higher risk donors was nearly equal to standard donors with Eurotransplant criteria failing to predict survival of marginal grafts. Modifying ECD criteria could improve graft allocation and potentially expand the donor pool.

Extracellular NAD+ response to post-hepatectomy liver failure: bridging preclinical and clinical findings.

Liver fibrosis progressing to cirrhosis is a major risk factor for liver cancer, impacting surgical treatment and survival. Our study focuses on the role of extracellular nicotinamide adenine dinucleotide (eNAD+) in liver fibrosis, analyzing liver disease patients undergoing surgery. Additionally, we explore NAD+'s therapeutic potential in a mouse model of extended liver resection and in vitro using 3D hepatocyte spheroids. eNAD+ correlated with aspartate transaminase (AST) and bilirubin after liver resection (AST: r = 0.2828, p = 0.0087; Bilirubin: r = 0.2584, p = 0.0176). Concordantly, post-hepatectomy liver failure (PHLF) was associated with higher eNAD+ peaks (n = 10; p = 0.0063). Post-operative eNAD+ levels decreased significantly (p < 0.05), but in advanced stages of liver fibrosis or cirrhosis, this decline not only diminished but actually showed a trend towards an increase. The expression of NAD+ biosynthesis rate-limiting enzymes, nicotinamide phosphoribosyltransferase (NAMPT) and nicotinamide mononucleotide adenylyltransferase 3 (NMNAT3), were upregulated significantly in the liver tissue of patients with higher liver fibrosis stages (p < 0.0001). Finally, the administration of NAD+ in a 3D hepatocyte spheroid model rescued hepatocytes from TNFalpha-induced cell death and improved viability (p < 0.0001). In a mouse model of extended liver resection, NAD+ treatment significantly improved survival (p = 0.0158) and liver regeneration (p = 0.0186). Our findings reveal that eNAD+ was upregulated in PHLF, and rate-limiting enzymes of NAD+ biosynthesis demonstrated higher expressions under liver fibrosis. Further, eNAD+ administration improved survival after extended liver resection in mice and enhanced hepatocyte viability in vitro. These insights may offer a potential target for future therapies.

Integrating the new systemic treatment landscape and surgical therapy in hepatocellular carcinoma.

The treatment landscape of hepatocellular carcinoma has evolved rapidly within the last decade. Minimally-invasive techniques have reached a new level of safety, affording surgeons to pursue more aggressive treatment strategies to ultimately improve oncological outcomes. These procedures have been increasingly applied to treat patients with more progressed tumors and in select case even patients with advanced stage disease confined to the liver. Concomitantly, a dramatic increase in research into immunotherapy has altered the treatment paradigm in advanced disease stages, where the emerging treatment regimens can provide durable responses in a subset of the patient population for whom prognosis is dramatically improved. These treatments are now tested in early-stage disease to address the pressing unmet need of high recurrence rates after resection and in intermediate stage to complement the proven efficacy of intraarterial embolization in delaying progression. This review provides an in-depth discussion of these trends and describes how the treatment landscape has already changed and which impediments remain.

Distinctive protein expression in elderly livers in a Sprague-Dawley rat model of normothermic ex vivo liver machine perfusion.

BACKGROUND: Liver grafts are frequently declined due to high donor age or age mismatch with the recipient. To improve the outcome of marginal grafts, we aimed to characterize the performance of elderly vs. young liver grafts in a standardized rat model of normothermic ex vivo liver machine perfusion (NMP). METHODS: Livers from Sprague-Dawley rats aged 3 or 12 months were procured and perfused for 6 h using a rat NMP system or collected as a reference group (n = 6/group). Tissue, bile, and perfusate samples were used for biochemical, and proteomic analyses. RESULTS: All livers cleared lactate during perfusion and continued to produce bile after 6 h of perfusion (614 mg/h). Peak urea levels in 12-month-old animals were higher than in younger animals. Arterial and portal venous pressure, bile production and pH did not differ between groups. Proteomic analysis identified a total of 1477 proteins with oxidoreductase and catalytic activity dominating the gene ontology analysis. Proteins such as aldehyde dehydrogenase 1A1 and 2-Hydroxyacid oxidase 2 were significantly more present in livers of older age. CONCLUSIONS: Young and elderly liver grafts exhibited similar viability during NMP, though proteomic analyses indicated that older grafts are less resilient to oxidative stress. Our study is limited by the elderly animal age, which corresponds to mature but not elderly human age typically seen in marginal human livers. Nevertheless, reducing oxidative stress could be a promising therapeutic target in the future.

Thrombogenicity assessment of perfusable tissue engineered constructs: a systematic review.

Vascular surgery faces a critical demand for novel vascular grafts that are biocompatible and thromboresistant. This urgency particularly applies to bypass operations involving small caliber vessels. In the realm of tissue engineering, the development of fully vascularized organs holds great promise as a solution to organ shortage for transplantation. To achieve this, it is imperative to (re-)construct a biocompatible and non-thrombogenic vascular network within these organs. In this systematic review, we identify, classify and discuss basic principles and methods used to perform in vitro/ex vivo dynamic thrombogenicity testing of perfusable tissue engineered organs and tissues. We conducted a pre-registered systematic review of studies published in the last 23 years according to PRISMA-P Guidelines, comprising a systematic data extraction, in-depth analysis and risk of bias assessment of 116 included studies. We identified shaking (n=28), flow loop (n=17), ex vivo (arterio-venous shunt, n=33) and dynamic in vitro models (n=38) as main approaches for thrombogenicity assessment. This comprehensive review unveils a prevalent lack of standardization and serves as a valuable guide in the design of standardized experimental setups.

Quality Assessment by Bile Composition in Normothermic Machine Perfusion of Rat Livers.

Background: The persistent challenge of organ scarcity in liver transplantation leads to an escalating dependence on organs obtained from extended criteria donors (ECD). Normothermic machine perfusion (NMP) is used for improved preservation. Due to the mimicked in vivo conditions during normothermic machine perfusion, the liver is metabolically active, which allows quality assessment during perfusion. Bile seems to be of rising interest in clinical studies, as it is easily collectible for analysis. As there are currently no data on biliary bile acids during NMP, the primary objective of this study was to use our experimental rodent NMP model to assess changes in bile composition through organ damage during perfusion to inform clinical evaluation of donor organs during NMP. Methods: Thirty livers from male Sprague-Dawley rats in five groups underwent 6 h of NMP using either erythrocyte-supplemented DMEM or Steen solution, with or without 30 min of warm ischemia time (WIT). We conducted regular measurements of AST, ALT, LDH, and urea levels in the perfusate at 3-hour intervals. Bile samples were analyzed for biliary pH, LDH, and gamma glutamyltransferase, as well as biliary bile acids via mass spectrometry and UHPLC. Results: Compared with regular livers, liver injury parameters were significantly higher in our donation after circulatory death (DCD) model. Bile production was significantly reduced in livers exposed to WIT, and the bile showed a significantly more alkaline pH. This correlated with the concentration of total bile acids, which was significantly higher in livers experiencing WIT. However, regular livers produced a higher total amount of biliary bile acids during perfusion. Taurocholic acid and its metabolites were most prominent. Secondary bile acids were significantly reduced during perfusion due to the missing enterohepatic circulation. Conclusions: WIT-induced liver injury affects bile composition within our small-animal NMP model. We hypothesize this phenomenon to be attributed to the energy-driven nature of bile secretion, potentially explaining why DCD livers produce less, yet more concentrated, bile. Our results may inform clinical studies, in which biliary bile acids might have a potential as a quantifiable viability marker in human NMP liver transplantation studies.

Harmonizing Definitions and Perspectives in Extreme Liver Surgery: A Delphi Experts Consensus.

OBJECTIVE: To propose to our community a common language about extreme liver surgery. BACKGROUND: The lack of a clear definition of extreme liver surgery prevents convincing comparisons of results among centers. METHODS: We used a two-round Delphi methodology to quantify consensus among liver surgery experts. For inclusion in the final recommendations, we established a consensus when the positive responses (agree and totally agree) exceeded 70%. The study steering group summarized and reported the recommendations. In general, a five-point Likert scale with a neutral central value was used, and in a few cases multiple choices. Results are displayed as numbers and percentages. RESULTS: A two-round Delphi study was completed by 38 expert surgeons in complex hepatobiliary surgery. The surgeon´s median age was 58 years old (52-63) and the median years of experience was 25 years (20-31). For the proposed definitions of total vascular occlusion, hepatic flow occlusion and inferior vein occlusion, the degree of agreement was 97%, 81% and 84%, respectively. In situ approach (64%) was the preferred, followed by ante situ (22%) and ex situ (14%). Autologous or cadaveric graft for hepatic artery or hepatic vein repair were the most recommended (89%). The use of veno-venous bypass or portocaval shunt revealed the divergence depending on the case. Overall, 75% of the experts agreed with the proposed definition for extreme liver surgery. CONCLUSION: Obtaining a consensus on the definition of extreme liver surgery is essential to guarantee the correct management of patients with highly complex hepatobiliary oncological disease. The management of candidates for extreme liver surgery involves comprehensive care ranging from adequate patient selection to the appropriate surgical strategy.

Defining Global Benchmarks for Laparoscopic Right Posterior Sectionectomy/H67: An International Multicenter Study.

OBJECTIVE: We aimed to establish global benchmark outcomes indicators for L-RPS/H67. BACKGROUND: Minimally invasive liver resections has seen an increase in uptake in recent years. Over time, challenging procedures as laparoscopic right posterior sectionectomies (L-RPS)/H67 are also increasingly adopted. METHODS: This is a post hoc analysis of a multicenter database of 854 patients undergoing minimally invasive RPS (MI-RPS) in 57 international centers in 4 continents between 2015 and 2021. There were 651 pure L-RPS and 160 robotic RPS (R-RPS). Sixteen outcome indicators of low-risk L-RPS cases were selected to establish benchmark cutoffs. The 75th percentile of individual center medians for a given outcome indicator was set as the benchmark cutoff. RESULTS: There were 573 L-RPS/H67 performed in 43 expert centers, of which 254 L-RPS/H67 (44.3%) cases qualified as low risk benchmark cases. The benchmark outcomes established for operation time, open conversion rate, blood loss ≥500 mL, blood transfusion rate, postoperative morbidity, major morbidity, 90-day mortality and textbook outcome after L-RPS were 350.8 minutes, 12.5%, 53.8%, 22.9%, 23.8%, 2.8%, 0% and 4% respectively. CONCLUSIONS: The present study established the first global benchmark values for L-RPS/H6/7. The benchmark provided an up-to-date reference of best achievable outcomes for surgical auditing and benchmarking.

Factors Associated with and Impact of Open Conversion in Laparoscopic and Robotic Minor Liver Resections: An International Multicenter Study of 10,541 Patients.

INTRODUCTION: Despite the increasing widespread adoption and experience in minimally invasive liver resections (MILR), open conversion occurs not uncommonly even with minor resections and as been reported to be associated with inferior outcomes. We aimed to identify risk factors for and outcomes of open conversion in patients undergoing minor hepatectomies. We also studied the impact of approach (laparoscopic or robotic) on outcomes. METHODS: This is a post-hoc analysis of 20,019 patients who underwent RLR and LLR across 50 international centers between 2004-2020. Risk factors for and perioperative outcomes of open conversion were analysed. Multivariate and propensity score-matched analysis were performed to control for confounding factors. RESULTS: Finally, 10,541 patients undergoing either laparoscopic (LLR; 89.1%) or robotic (RLR; 10.9%) minor liver resections (wedge resections, segmentectomies) were included. Multivariate analysis identified LLR, earlier period of MILR, malignant pathology, cirrhosis, portal hypertension, previous abdominal surgery, larger tumor size, and posterosuperior location as significant independent predictors of open conversion. The most common reason for conversion was technical issues (44.7%), followed by bleeding (27.2%), and oncological reasons (22.3%). After propensity score matching (PSM) of baseline characteristics, patients requiring open conversion had poorer outcomes compared with successful MILR cases as evidenced by longer operative times, more blood loss, higher requirement for perioperative transfusion, longer duration of hospitalization and higher morbidity, reoperation, and 90-day mortality rates. CONCLUSIONS: Multiple risk factors were associated with conversion of MILR even for minor hepatectomies, and open conversion was associated with significantly poorer perioperative outcomes.