Multicenter validation of the liver graft assessment following transplantation (L-GrAFT) score for assessment of early allograft dysfunction

Upper limit of normothermic machine preservation of liver grafts from donation after circulatory death yet to be defined

BACKGROUND

The normothermic machine perfusion pump (NMPP) could shape the future of transplantation. Providing ex-vivo optimization, NMPP attenuates ischemic insult while replenishing energy. An understanding of machine perfusion time (MPT) impact and potential clinical benefits is paramount and necessitates exploration.

AIM

To investigate the relationship between MPT and post-transplant graft function.

METHODS

Retrospective review of the first 50 donation after circulatory death (DCD) grafts preserved using NMPP in a tertiary institution was performed. Essential preservation time points, graft parameters, recipient information, and postoperative outcomes were prospectively recorded. Early allograft dysfunction (EAD), L-Graft₇ score and 90-day outcomes were collected for all grafts. The first 20 recipients were allocated into the early group, considered the learning curve population for the center. The subsequent 30 were allocated into the late group. Recipients were also stratified into cohorts depending on MPT, i.e., short (< 8 hours), medium (8-16 hours) and long (> 16 hours).

RESULTS

NMPP operational parameters were not predictive of EAD, L-GrAFT₇ or 90-day outcomes. The early group had significantly less MPT and cold ischemia time than the late group (553 minutes vs 850 minutes, P < 0.001) and (127.5 minutes vs 154 minutes, P = 0.025), respectively. MPT had no impact in either group.

CONCLUSION

Increased MPT of DCD liver grafts had no adverse recipient results for the times utilized in this population, indicating its upper limits, likely beyond 24 hours, are not demonstrated within this study. Future studies are necessary to determine whether longer MPT is beneficial or detrimental to graft function and, if the latter, what is the maximum safe duration. Further studies of the effect of normothermic machine perfusion pump duration on long-term outcomes are also needed.

Mastering the narrative: Precision reporting of risk and outcomes in liver transplantation

Liver transplantation is associated with a high risk of postoperative complications due to the complexity of the surgical procedure, recipient disease severity and the wide range of graft quality, which remains somewhat unpredictable. However, survival rates after transplantation continue to improve and the focus has thus turned to other clinically relevant endpoints including post-transplant complications, patient quality of life and costs. Procedures like liver transplantation offer the entire spectrum of post-surgical events, even in donor-recipient constellations deemed of low risk within recently defined benchmark criteria. The Clavien-Dindo classification and the CCI (comprehensive complication index) were established to assess postoperative morbidity and are widely utilised across surgical specialties. These scores depend on the number and grade of complications, which reflect the interventions required, and are frequently used to assess specific donor-recipient risk profiles and new approaches, such as machine perfusion. However, these scores are associated with inter-observer variability when used in practice, mainly due to the lack of uniform definitions. The concept of benchmarking was recently introduced in surgery and transplantation as a mechanism of standardising expected donor/recipient risk with outcomes within the first year after surgery. However, the management of complications differs significantly worldwide, as does the rating scale assigned to various complications. This may lead to inhomogeneous interpretation of study results, leading to difficulty in assessing the clinical effects of novel preservation technologies and other therapeutics in liver transplantation. This article critically discusses frequent challenges associated with risk and outcome assessment following liver transplantation.

Value of Factor V in the diagnosis of early graft dysfunction after liver transplantation: Internal validation

Primary graft dysfunction is a major early complication following liver transplantation, potentially leading to retransplantation or patient death. Coagulation Factor V (FV) and ALT have emerged as important biomarkers in assessing liver function, yet their role as early predictors of graft loss has not been fully validated. The aim of this study is to conduct an internal validation of published results on the applicability of FV and ALT for diagnosing graft dysfunction and its predictive ability for graft loss within the first 90 days. We conducted a retrospective cohort study including 513 adult recipients from 2012 to 2023 at the Regional University Hospital of Málaga. FV and ALT levels were measured on postoperative day 2, and patients were categorized based on FV <37.5 and ALT >1539. The association with 90-day graft loss was analyzed. Graft loss occurred in 43 patients (8.4%) within the first 90 days. The combination of FV <37.5 and ALT >1539 on postoperative day 2 demonstrated a specificity of 99% and a test efficiency of 94% in predicting graft loss. Patients meeting both criteria had a 74-fold increased risk of graft loss, with most losses occurring within the first week, and a median survival of 4 days. These findings suggest that FV and ALT on postoperative day 2 are reliable early markers for predicting graft loss, enabling risk stratification and guiding critical decisions regarding early retransplantation in the immediate postoperative period.

Protocol for an international multicenter, prospective, observational, non-competitive, study to validate and optimise prediction models of 90-day and 1-year allograft failure after liver transplantation: The global IMPROVEMENT Study

More liver transplants (LT) are performed worldwide thanks to extended criteria donors (ECD). This is paralleled by a supposed increased risk of allograft failure (AF) at 90 and 365 days. This study has been designed to portray the LT practice worldwide and investigate models of AF prediction and the impact of risk mitigation strategies for further improving graft and patient outcomes. This is a multicenter, international, non-competitive, observational two segment study on consecutive LTs over two periods (2017-2019 and 2022-2024). A steering committee of LT experts defined the study protocol. The prospective segment will enroll 750 patients from 15 high-volume LT centers (50 per center), and the retrospective segment will enrol 4200 patients from 56 LT centers (75 per center). To provide a snapshot of the LT activity globally and to develop new algorithms for the timely prediction of AF at 90 and 365 days post-LT. The study also aims (1) to validate the existing predictive models and (2) to investigate the best time for re-transplantation, paying attention to the differences in AF and Ischemic cholangiopathy according to the donor types and mitigation strategies implemented in the various settings. Since the adoption of machine perfusion has increased in different proportions worldwide, models will be adjusted according to this parameter. Finally, retrospective and prospective data will be available for further stratifications and modelling according to the degree of decompensation at transplant, gender match, postoperative complications and their management. This protocol was approved by Fondazione Policlinico Universitario Agostino Gemelli IRCCS Ethics Committee (study ID: 4571) and the Institutional Review Board of the University of California, Los Angeles. The provisional study protocol was submitted to the main scientific international societies in the transplant field. Results will be published in international peer-reviewed journals and presented at congresses.

Thoracoabdominal Normothermic Regional Perfusion: Real-world Experience and Outcomes of DCD Liver Transplantation

Background

Donation after circulatory death liver transplantation (DCD LT) is underused given historical outcomes fraught with ischemic cholangiopathy (IC). We aimed to assess 6-mo IC in LT from DCD via normothermic regional perfusion (NRP) compared with DCD via static cold storage (SCS).

Methods

A retrospective review of adult Maastricht-III DCD liver donors and recipients at the University of Colorado Hospital from January 1, 2017, to August 27, 2024, was performed. The 6-mo IC rate was compared between NRP and SCS. Secondary outcomes included biochemical assessments of accepted versus declined NRP liver allografts and allograft and patient survival for NRP and SCS groups.

Results

One hundred sixty-two DCD LTs (SCS = 79; NRP = 97) were performed and 150 recipients (SCS = 74; NRP = 86) reached 6-mo follow-up. Six-month IC was lower for NRP compared with SCS (1.2% versus 9.5%, P = 0.03). The Donor Risk Index (2.44 [2.02-2.82] versus 2.17 [1.97-2.30], P = 0.002) and UK DCD Risk Score (4.2 ± 2.9 versus 3.2 ± 2.3, P = 0.008) were higher for NRP versus SCS. The Liver Graft assessment Following Transplantation score was less for NRP compared with SCS (-3.3 versus -3.1, P < 0.05). There were several differences in median biochemical parameters during NRP between accepted and declined livers, including higher terminal biliary bicarbonate (22.7 [20.9-29.1] versus 10.8 [7.6-13.1] mEq/L, P = 0.004). There were no significant differences in 12-mo allograft or patient survival for NRP versus SCS.

Conclusions

NRP is a disruptive innovation that improves the utilization of DCD livers. Despite higher-risk donor-recipient pairing for NRP compared with SCS, we demonstrate a decrease in IC for NRP. These data facilitate benchmarking of thoracoabdominal NRP DCD LT and support further protocol development.

Individual mHLA-DR trajectories in the ICU as predictors of early infections following liver transplantation: a prospective observational study

BACKGROUND

Infections are a leading cause of early mortality after liver transplantation (LT). Prior to transplantation, cirrhosis-associated immune dysfunction significantly increases the risk of infection. This study investigated the potential of immune monitoring, with a focus on monocytic HLA-DR (mHLA-DR) expression, as a predictor of post-LT complications.

METHODS

We conducted a prospective study on 130 patients awaiting LT at Lyon University Hospital to assess mHLA-DR expression, lymphocyte subsets, and T-cell function before and after LT. Multivariate analysis and K-means longitudinal clustering were performed to explore the relationships between immune trajectories and clinical outcomes.

RESULTS

Among the 99 patients who underwent LT, 35.4% experienced infections early post-LT. No difference in outcome was found regarding lymphocyte count or function. Delayed mHLA-DR recovery (Day 7 < 11,000 AB/C) and pre-LT MELD scores > 30 emerged as independent infection risk factors, with ORs of 12.1 [4.4-38.2], p < 0.0001 and 4.9 [1.4-18.4], p = 0.01, respectively. Patients with delayed mHLA-DR restoration also had reduced one-year survival (77.8% versus 98.3%, p = 0.003). K-means clustering revealed three distinct mHLA-DR recovery profiles, with the slowest recovery group showing the poorest outcomes.

CONCLUSIONS

Our findings highlight mHLA-DR as an early predictor of post-LT infections. Monitoring post-LT immune function through mHLA-DR expression could guide individualized management strategies to improve outcomes. Trial registration The study was registered in the ClinicalTrials.gov registry: NCT03995537, date: June 20, 2019.

Perspectives and Tools in Liver Graft Assessment: A Transformative Era in Liver Transplantation

Liver transplantation is a critical and evolving field in modern medicine, offering life-saving treatment for patients with end-stage liver disease and other hepatic conditions. Despite its transformative potential, transplantation faces persistent challenges, including a global organ shortage, increasing liver disease prevalence, and significant waitlist mortality rates. Current donor evaluation practices often discard potentially viable livers, underscoring the need for refined graft assessment tools. This review explores advancements in graft evaluation and utilization aimed at expanding the donor pool and optimizing outcomes. Emerging technologies, such as imaging techniques, dynamic functional tests, and biomarkers, are increasingly critical for donor assessment, especially for marginal grafts. Machine learning and artificial intelligence, exemplified by tools like LiverColor, promise to revolutionize donor-recipient matching and liver viability predictions, while bioengineered liver grafts offer a future solution to the organ shortage. Advances in perfusion techniques are improving graft preservation and function, particularly for donation after circulatory death (DCD) grafts. While challenges remain-such as graft rejection, ischemia-reperfusion injury, and recurrence of liver disease-technological and procedural advancements are driving significant improvements in graft allocation, preservation, and post-transplant outcomes. This review highlights the transformative potential of integrating modern technologies and multidisciplinary approaches to expand the donor pool and improve equity and survival rates in liver transplantation.

Suppression of Hepatocyte Ferroptosis via USP19-Mediated Deubiquitination of SLC7A11 in Ischemia-Free Liver Transplantation

Ischemia-free liver transplantation (IFLT) is developed as a novel clinical approach to avoid ischemia-reperfusion injury (IRI). This study aims to identify the most distinguished programmed cell death pathway in grafts undergoing IFLT versus conventional liver transplantation (CLT) and to explore the underlying mechanism. Ferroptosis is the most distinct programmed cell death form between IFLT and CLT grafts. Among various cell death inhibitors, the ferroptosis inhibitor (Ferrostain-1) is the most effective one to prevent hepatocytes from damage induced by oxygen deprivation/reoxygenation (OGD/R). Hepatocyte ferroptosis is significantly alleviated in IFLT versus CLT grafts in both human beings and pigs. Ubiquitination enzyme screening identifies augmented amounts of ubiquitin-specific protease 19 (USP19) in IFLT versus CLT grafts. The upregulation of USP19 in the grafts is correlated with reduced pathological Suzuki's score, lower post-transplant peak liver enzyme level, and less early allograft dysfunction in liver transplant recipients. USP19 overexpression mitigates post-transplant liver injury in mice. Mechanistically, USP19 inhibits the degradation of solute carrier family 7 member 11 (SLC7A11) by removing its K63-linked ubiquitin chains. Notably, USP19 overexpression reduces ferroptosis and IRI in a SLC7A11-dependent manner in mice. Collectively, USP19-mediated suppression of hepatocyte ferroptosis via deubiquitinating SLC7A11 is a key mechanism by which IFLT abrogates graft IRI.

Liver stiffness: a novel imaging biomarker by ultrasound elastography for prediction of early allograft failure following liver transplantation

OBJECTIVES

The objective of this study was to evaluate the role of Liver Stiffness Measurement (LSM) and serum transaminase levels for predicting early allograft failure (EAF) after liver transplantation (LT).

METHODS

A total of 189 patients who underwent LT were prospectively recruited in the study. Of these patients, 13 cases died or received re-transplantation within 90 days after surgery were classified as EAF group, while rest 176 patients were included in the non-EAF group. LSM values and serum transaminase levels within 1 week after operation were recorded and compared between two groups. The area under the curve (AUC) was utilized to assess the performance of LSM, serum transaminase and their combination in predicting EAF.

RESULTS

The earliest significant difference in LSM between EAF and non-EAF group was observed on postoperative day 3 (POD-3) (p = 0.046). Comparing to non-EAF group, patients in the EAF group had higher aspartate-aminotransferase (AST) and alanine aminotransferase (ALT) on postoperative day 2 (POD-2)(p = 0.009, 0.033), and also demonstrated higher AST on POD-3 (p = 0.021). Furthermore, the reduction rate of AST/ALT from day 1 to day 3 (AST/ALT Red) were slower (p = 0.001, 0.014) in EAF group. Using a LSM value > 12.1 kPa and an AST level > 339U/L on POD-3 predicted EAF with a sensitivity of 89%, a specificity of 86%, and an AUC of 0.926, surpassing the traditional early allograft dysfunction (EAD) model.

CONCLUSIONS

The combination of LSM values and AST levels on the third day after LT can effectively predict EAF and facilitate timely interventions.

Role of the Lymphocyte Count-to-C-Reactive Protein Ratio in the Risk Stratification for High EASE Scores After Living Donor Liver Transplantation: A Retrospective Observational Cohort Study

Background: Early allograft failure (EAF) significantly contributes to mortality, necessitating re-transplantation following liver transplantation. The EAF simplified estimation (EASE) score has been recently developed to predict EAF. We aimed to assess the predictive capacity of high EASE scores for EAF and postoperative outcomes and to evaluate the association between the lymphocyte count-to-C-reactive protein ratio (LCR) and high EASE scores after living donor liver transplantation (LDLT). Methods: We retrospectively analyzed the data of 808 patients who underwent LDLT. After excluding 16 patients with incomplete laboratory data, the final cohort included 792 patients. Patients with EASE scores ≥-0.74 were categorized into the high EASE group. Multivariate logistic regression was used to examine the association between the LCR and high EASE scores. Results: High EASE scores demonstrated superior predictive accuracy for EAF development relative to that of the early allograft dysfunction (EAD) model (p = 0.018) and were more closely associated with overall mortality (p = 0.033). A preoperative LCR < 12.7 significantly increased the odds (odds ratio, 3.3; confidence interval, 1.997-5.493) of exhibiting high EASE scores post-LDLT, alongside preoperative hematocrit levels, operative duration, intraoperative continuous renal replacement therapy, administered calcium dose, mean heart rate, and donor age. Conclusions: The EASE score could offer enhanced utility for predicting EAF and overall mortality following LDLT relative to that of EAD. Identifying and managing risk factors, including low LCR values, for elevated EASE scores is essential for improving patient prognoses.

Intraoperative Anesthetic Strategies to Mitigate Early Allograft Dysfunction After Orthotopic Liver Transplantation: A Narrative Review

Orthotopic liver transplantation (OLT) is the most effective treatment for patients with end-stage liver disease (ESLD). Hepatic insufficiency within a week of OLT, termed early allograft dysfunction (EAD), occurs in 20% to 25% of deceased donor OLT recipients and is associated with morbidity and mortality. Primary nonfunction (PNF), the most severe form of EAD, leads to death or retransplantation within 7 days. The etiology of EAD is multifactorial, including donor, recipient, and surgery-related factors, and largely driven by ischemia-reperfusion injury (IRI). IRI is an immunologic phenomenon characterized by dysregulation of cellular oxygen homeostasis and innate immune defenses in the allograft after temporary cessation (ischemia) and later restoration (reperfusion) of oxygen-rich blood flow. The rising global demand for OLT may lead to the use of marginal allografts, which are more susceptible to IRI, and thus lead to an increased incidence of EAD. It is thus imperative the anesthesiologist is knowledgeable about EAD, namely its pathophysiology and intraoperative strategies to mitigate its impact. Intraoperative strategies can be classified by 3 phases, specifically donor allograft procurement, storage, and recipient reperfusion. During procurement, the anesthesiologist can use pharmacologic preconditioning with volatile anesthetics, consider preharvest hyperoxemia, and attenuate the use of norepinephrine as able. The anesthesiologist can advocate for normothermic regional perfusion (NRP) and machine perfusion during allograft storage at their institution. During recipient reperfusion, the anesthesiologist can optimize oxygen exposure, consider adjunct anesthetics with antioxidant-like properties, and administer supplemental magnesium. Unfortunately, there is either mixed, little, or no data to support the routine use of many free radical scavengers. Given the sparse, limited, or at times conflicting evidence supporting some of these strategies, there are ample opportunities for more research to find intraoperative anesthetic strategies to mitigate the impact of EAD and improve postoperative outcomes in OLT recipients.

Development and validation of a model for early survival prediction following liver transplantation based on donor and recipient characteristics

BACKGROUND

Circulating cytokine levels not only correlate with the progression of liver disease but also serve as indicators for the infection status of the body. Growing evidence points to the connection between donor cytokines and graft function following transplantation. This study set out to explore the clinical significance of donor cytokines in predicting liver transplantation prognosis.

METHODS

Data from 172 deceased donor liver transplantations conducted between 2017 and 2022, with available donor serum cytokine information, were collected. The subjects were randomly divided into estimation (n = 120) and validation (n = 52) groups to establish and validate the model. The newly developed SA10 score was compared against established models EAD, MEAF, L-GrAFT7, and L-GrAFT10.

RESULTS

Donor IL-10, along with donor age and recipient AST peak value within the first 7 days post-operation, was identified as an independent factor associated with recipient survival and was incorporated into the SA10 score. SA10 exhibited robust predictive capability, particularly for 1-month survival (AUC = 0.90, 95% CI = 0.84-0.96), outperforming EAD (AUC = 0.75, 95% CI = 0.60-0.90, p = 0.04) and L-GrAFT7 (AUC = 0.65, 95% CI = 0.49-0.81, p < 0.01). Comparable performance was observed between SA10, MEAF, and L-GrAFT10.

CONCLUSION

Donor IL-10 independently influences recipient survival, with the SA10 score demonstrating comparable and even superior predictive ability compared to existing models.

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 criteria donor (ECD) criteria.

BACKGROUND

Eurotransplant uses a broad definition of ECD criteria (age >65 years, steatosis >40%, body mass index >30 kg/m 2 , intensive care unit stay >7 days, donation after circulatory death, 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 and the U.S. Scientific Registry of Transplant Recipients (SRTR) from 2006 to 2016. Results were validated with recent SRTR data (2017-2022). Donors were classified according to the Eurotransplant ECD criteria, donation after circulatory death was excluded. Data were analyzed with cutoff 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 body mass index in the United States (28%). Except for donor age, grafts meeting ECD criteria were not associated with impaired 1 or 3-year survival. Cutoffs had little to no predictive value for 30-day graft survival (area under the receiver operating curve: 0.49-0.52) and were nominally higher for age (72 vs 65 years) in Germany as compared with 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.

Hyperspectral imaging of human liver allografts for prediction of initial graft function

PURPOSE

Ischemia reperfusion injury represents a significant yet difficult to assess risk factor for short- and long-term graft impairment in human liver transplantation (LT). As a non-invasive, non-ionizing tool, hyperspectral imaging (HSI) is capable of correlating optical properties with organ microperfusion. Hence, we here performed a study of human liver allografts assessed by HSI for microperfusion and prediction of initial graft function.

METHODS

Images of liver parenchyma of 37 human liver allografts were acquired at bench preparation, during normothermic machine perfusion (NMP), if applicable, and after reperfusion in the recipient. A specialized HSI acquisition software computed oxygen saturation (StO2), tissue hemoglobin indices (THI), near infrared perfusion indices (NIR), and tissue water indices (TWI). HSI parameters were analyzed for differences with regard to preservation technique, reperfusion sequence and presence of early allograft dysfunction (EAD).

RESULTS

Organ preservation was performed by means of NMP (n = 31) or static cold storage (SCS; n = 6). Patients' demographics, donor characteristics, presence of EAD (NMP 36.7% vs. SCS 50%, p = 0.6582), and HSI parameters were comparable between both groups of preservation method. In organs developing EAD, NIR at 1, 2, and 4 h NMP and after reperfusion in the recipient was significantly lower (1 h NMP: 18.6 [8.6-27.6] vs. 28.3 [22.5-39.4], p = 0.0468; 2 h NMP: 19.4 [8.7-30.4] vs. 37.1 [27.5-44.6], p = 0.0011; 4 h NMP: 26.0 [6.8-37.1] vs. 40.3 [32.3-49.9], p = 0.0080; reperfusion: 13.0 [11.5-34.3] vs. 30.6 [19.3-44.0], p = 0.0212).

CONCLUSION

HSI assessment of human liver allografts is feasible during organ preservation and in the recipient. NIR during NMP and after reperfusion might predict the onset of EAD. Larger trials are warranted for assessment of this novel technique in human LT.

FGF21 modulates immunometabolic homeostasis via the ALOX15/15-HETE axis in early liver graft injury

Fibroblast growth factor 21 (FGF21) is essential for modulating hepatic homeostasis, but the impact of FGF21 on liver graft injury remains uncertain. Here, we show that high FGF21 levels in liver graft and serum are associated with improved graft function and survival in liver transplantation (LT) recipients. FGF21 deficiency aggravates early graft injury and activates arachidonic acid metabolism and regional inflammation in male mouse models of hepatic ischemia/reperfusion (I/R) injury and orthotopic LT. Mechanistically, FGF21 deficiency results in abnormal activation of the arachidonate 15-lipoxygenase (ALOX15)/15-hydroxy eicosatetraenoic acid (15-HETE) pathway, which triggers a cascade of innate immunity-dominated pro-inflammatory responses in grafts. Notably, the modulating role of FGF21/ALOX15/15-HETE pathway is more significant in steatotic livers. In contrast, pharmacological administration of recombinant FGF21 effectively protects against hepatic I/R injury. Overall, our study reveals the regulatory mechanism of FGF21 and offers insights into its potential clinical application in early liver graft injury after LT.

Validation and performance of three scoring systems for predicting primary non-function and early allograft failure after liver transplantation

BACKGROUND

Primary non-function (PNF) and early allograft failure (EAF) after liver transplantation (LT) seriously affect patient outcomes. In clinical practice, effective prognostic tools for early identifying recipients at high risk of PNF and EAF were urgently needed. Recently, the Model for Early Allograft Function (MEAF), PNF score by King's College (King-PNF) and Balance-and-Risk-Lactate (BAR-Lac) score were developed to assess the risks of PNF and EAF. This study aimed to externally validate and compare the prognostic performance of these three scores for predicting PNF and EAF.

METHODS

A retrospective study included 720 patients with primary LT between January 2015 and December 2020. MEAF, King-PNF and BAR-Lac scores were compared using receiver operating characteristic (ROC) and the net reclassification improvement (NRI) and integrated discrimination improvement (IDI) analyses.

RESULTS

Of all 720 patients, 28 (3.9%) developed PNF and 67 (9.3%) developed EAF in 3 months. The overall early allograft dysfunction (EAD) rate was 39.0%. The 3-month patient mortality was 8.6% while 1-year graft-failure-free survival was 89.2%. The median MEAF, King-PNF and BAR-Lac scores were 5.0 (3.5-6.3), -2.1 (-2.6 to -1.2), and 5.0 (2.0-11.0), respectively. For predicting PNF, MEAF and King-PNF scores had excellent area under curves (AUCs) of 0.872 and 0.891, superior to BAR-Lac (AUC = 0.830). The NRI and IDI analyses confirmed that King-PNF score had the best performance in predicting PNF while MEAF served as a better predictor of EAD. The EAF risk curve and 1-year graft-failure-free survival curve showed that King-PNF was superior to MEAF and BAR-Lac scores for stratifying the risk of EAF.

CONCLUSIONS

MEAF, King-PNF and BAR-Lac were validated as practical and effective risk assessment tools of PNF. King-PNF score outperformed MEAF and BAR-Lac in predicting PNF and EAF within 6 months. BAR-Lac score had a huge advantage in the prediction for PNF without post-transplant variables. Proper use of these scores will help early identify PNF, standardize grading of EAF and reasonably select clinical endpoints in relative studies.

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.

Advancements in Predictive Tools for Primary Graft Dysfunction in Liver Transplantation: A Comprehensive Review

Orthotopic liver transplantation stands as the sole curative solution for end-stage liver disease. Nevertheless, the discrepancy between the demand and supply of grafts in transplant medicine greatly limits the success of this treatment. The increasing global shortage of organs necessitates the utilization of extended criteria donors (ECD) for liver transplantation, thereby increasing the risk of primary graft dysfunction (PGD). Primary graft dysfunction (PGD) encompasses early allograft dysfunction (EAD) and the more severe primary nonfunction (PNF), both of which stem from ischemia-reperfusion injury (IRI) and mitochondrial damage. Currently, the only effective treatment for PNF is secondary transplantation within the initial post-transplant week, and the occurrence of EAD suggests an elevated, albeit still uncertain, likelihood of retransplantation urgency. Nonetheless, the ongoing exploration of novel IRI mitigation strategies offers hope for future improvements in PGD outcomes. Establishing an intuitive and reliable tool to predict upcoming graft dysfunction is vital for early identification of high-risk patients and for making informed retransplantation decisions. Accurate diagnostics for PNF and EAD constitute essential initial steps in implementing future mitigation strategies. Recently, novel methods for PNF prediction have been developed, and several models for EAD assessments have been introduced. Here, we provide an overview of the currently scrutinized predictive tools for PNF and EAD evaluation strategies, accompanied by recommendations for future studies.

Transcriptional Profiling Underscores the Role of Preprocurement Allograft Metabolism and Innate Immune Status on Outcomes in Human Liver Transplantation

Objective

The adverse effects of ischemia-reperfusion injury (IRI) remain a principal barrier to a successful outcome after lifesaving orthotopic liver transplantation (OLT). Gene expression during different phases of IRI is dynamic and modified by individual exposures, making it attractive for identifying potential therapeutic targets for improving the number of suitable organs for transplantation and patient outcomes. However, data remain limited on the functional landscape of gene expression during liver graft IRI, spanning procurement to reperfusion and recovery. Therefore, we sought to characterize transcriptomic profiles of IRI during multiple phases in human OLT.

Methods

We conducted clinical data analyses, histologic evaluation, and RNA sequencing of 17 consecutive human primary OLT. We performed liver allograft biopsies at 4 time points: baseline (B, before donor cross-clamp), at the end of cold ischemia (CI), during early reperfusion (ER, after revascularization), and during late reperfusion (LR). Data were generated and then recipients grouped by post-OLT outcomes categories: immediate allograft function (IAF; n = 11) versus early allograft dysfunction (EAD; n = 6) groups.

Results

We observed that CI (vs B) modified a transcriptomic landscape enriched for a metabolic and immune process. Expression levels of hallmark inflammatory response genes were higher transitioning from CI to ER and decreased from ER to LR. IAF group predominantly showed higher bile and fatty acid metabolism activity during LR compared with EAD group, while EAD group maintained more immunomodulatory activities. Throughout all time points, EAD specimens exhibited decreased metabolic activity in both bile and fatty acid pathways.

Conclusions

We report transcriptomic profiles of human liver allograft IRI from prepreservation in the donor to posttransplantation in the recipient. Immunomodulatory and metabolic landscapes across ER and LR phases were different between IAF and EAD allografts. Our study also highlights marker genes for these biological processes that we plan to explore as novel therapeutic targets or surrogate markers for severe allograft injury in clinical OLT.

An integrated proteomics and metabolomics approach to assess graft quality and predict early allograft dysfunction after liver transplantation: a retrospective cohort study

BACKGROUND

Early allograft dysfunction (EAD) is a common complication after liver transplantation (LT) and is associated with poor prognosis. Graft itself plays a major role in the development of EAD. We aimed to reveal the EAD-specific molecular profiles to assess graft quality and establish EAD predictive models.

METHODS

A total of 223 patients who underwent LT were enrolled and divided into training ( n =73) and validation ( n =150) sets. In the training set, proteomics was performed on graft biopsies, together with metabolomics on paired perfusates. Differential expression, enrichment analysis, and protein-protein interaction network were used to identify the key molecules and pathways involved. EAD predictive models were constructed using machine learning and verified in the validation set.

RESULTS

A total of 335 proteins were differentially expressed between the EAD and non-EAD groups. These proteins were significantly enriched in triglyceride and glycerophospholipid metabolism, neutrophil degranulation, and the MET-related signaling pathway. The top 12 graft proteins involved in the aforementioned processes were identified, including GPAT1, LPIN3, TGFB1, CD59, and SOS1. Moreover, downstream metabolic products, such as lactate dehydrogenase, interleukin-8, triglycerides, and the phosphatidylcholine/phosphorylethanolamine ratio in the paired perfusate displayed a close relationship with the graft proteins. To predict the occurrence of EAD, an integrated model using perfusate metabolic products and clinical parameters showed areas under the curve of 0.915 and 0.833 for the training and validation sets, respectively. It displayed superior predictive efficacy than that of currently existing models, including donor risk index and D-MELD scores.

CONCLUSIONS

We identified novel biomarkers in both grafts and perfusates that could be used to assess graft quality and provide new insights into the etiology of EAD. Herein, we also offer a valid tool for the early prediction of EAD.

Portable hypothermic oxygenated machine perfusion for organ preservation in liver transplantation: A randomized, open-label, clinical trial

BACKGROUND AND AIMS

In liver transplantation, cold preservation induces ischemia, resulting in significant reperfusion injury. Hypothermic oxygenated machine perfusion (HMP-O 2 ) has shown benefits compared to static cold storage (SCS) by limiting ischemia-reperfusion injury. This study reports outcomes using a novel portable HMP-O 2 device in the first US randomized control trial.

APPROACH AND RESULTS

The PILOT trial (NCT03484455) was a multicenter, randomized, open-label, noninferiority trial, with participants randomized to HMP-O 2 or SCS. HMP-O 2 livers were preserved using the Lifeport Liver Transporter and Vasosol perfusion solution. The primary outcome was early allograft dysfunction. Noninferiority margin was 7.5%. From April 3, 2019, to July 12, 2022, 179 patients were randomized to HMP-O 2 (n=90) or SCS (n=89). The per-protocol cohort included 63 HMP-O 2 and 73 SCS. Early allograft dysfunction occurred in 11.1% HMP-O 2 (N=7) and 16.4% SCS (N=12). The risk difference between HMP-O 2 and SCS was -5.33% (one-sided 95% upper confidence limit of 5.81%), establishing noninferiority. The risk of graft failure as predicted by Liver Graft Assessment Following Transplant score at seven days (L-GrAFT 7 ) was lower with HMP-O 2 [median (IQR) 3.4% (2.4-6.5) vs. 4.5% (2.9-9.4), p =0.024]. Primary nonfunction occurred in 2.2% of all SCS (n=3, p =0.10). Biliary strictures occurred in 16.4% SCS (n=12) and 6.3% (n=4) HMP-O 2 ( p =0.18). Nonanastomotic biliary strictures occurred only in SCS (n=4).

CONCLUSIONS

HMP-O 2 demonstrates safety and noninferior efficacy for liver graft preservation in comparison to SCS. Early allograft failure by L-GrAFT 7 was lower in HMP-O 2 , suggesting improved early clinical function. Recipients of HMP-O 2 livers also demonstrated a lower incidence of primary nonfunction and biliary strictures, although this difference did not reach significance.

L-GrAFT7 has High Accuracy in Predicting Early Allograft Failure after Liver Transplantation: A Multicenter Cohort Study in China

Background and Aims

Increasing utilization of extended criteria donor leads to an increasing rate of early allograft failure after liver transplantation. However, consensus of definition of early allograft failure is lacking.

Methods

A retrospective, multicenter study was performed to validate the Liver Graft Assessment Following Transplantation (L-GrAFT) risk model in a Chinese cohort of 942 adult patients undergoing primary liver transplantation at three Chinese centers. L-GrAFT (L-GrAFT7 and L-GrAFT10) was compared with existing models: the Early Allograft Failure Simplified Estimation (EASE) score, the model of early allograft function (MEAF), and the Early Allograft Dysfunction (EAD) model. Univariate and multivariate logistic regression were used to find risk factors of L-GrAFT high-risk group.

Results

L-GrAFT7 had an area under the curve of 0.85 in predicting 90-day graft survival, significantly superior to MEAF [area under the curve (AUC=0.78, p=0.044)] and EAD (AUC=0.78, p=0.006), while there was no statistical significance between the predicting abilities of L-GrAFT7 and EASE (AUC=0.84, p>0.05). Furthermore, L-GrAFT7 maintains good predicting ability in the subgroup of high-donor risk index (DRI) cases (AUC=0.83 vs. MEAF, p=0.007 vs. EAD, p=0.014) and recipients of donors after cardiac death (AUC=0.92 vs. EAD, p<0.001). Through multivariate analysis, pretransplant bilirubin level, units of packed red blood cells, and the DRI score were selected as independent risk factors of a L-GrAFT7 high-risk group.

Conclusions

The accuracy of L-GrAFT7 in predicting early allograft failure was validated in a Chinese multicenter cohort, indicating that it has the potential to become an accurate endpoint of clinical practice and transitional study of machine perfusion.

Arterial blood pressure waveform in liver transplant surgery possesses variability of morphology reflecting recipients' acuity and predicting short term outcomes

We investigated clinical information underneath the beat-to-beat fluctuation of the arterial blood pressure (ABP) waveform morphology. We proposed the Dynamical Diffusion Map algorithm (DDMap) to quantify the variability of morphology.  The underlying physiology could be the compensatory mechanisms involving complex interactions between various physiological mechanisms to regulate the cardiovascular system. As a liver transplant surgery contains distinct periods, we investigated its clinical behavior in different surgical steps. Our study used DDmap algorithm, based on unsupervised manifold learning, to obtain a quantitative index for the beat-to-beat variability of morphology. We examined the correlation between the variability of ABP morphology and disease acuity as indicated by Model for End-Stage Liver Disease (MELD) scores, the postoperative laboratory data, and 4 early allograft failure (EAF) scores. Among the 85 enrolled patients, the variability of morphology obtained during the presurgical phase was best correlated with MELD-Na scores. The neohepatic phase variability of morphology was associated with EAF scores as well as postoperative bilirubin levels, international normalized ratio, aspartate aminotransferase levels, and platelet count. Furthermore, variability of morphology presents more associations with the above clinical conditions than the common BP measures and their BP variability indices. The variability of morphology obtained during the presurgical phase is indicative of patient acuity, whereas those during the neohepatic phase are indicative of short-term surgical outcomes.

Early allograft dysfunction after living donor liver transplantation-current concepts and future directions

Early allograft dysfunction (EAD) after liver transplantation is a significant clinical problem that negatively impacts graft and patient outcomes. The rising incidence of EAD and what it means concerning living donor liver transplantation (LDLT) is an area of great interest. However, EAD after LDLT is a complex research topic yet to be reviewed comprehensively. Most of the literature on EAD is based on experience in deceased donor liver transplantation, and limited information is available in the context of LDLT. Thus, in this review, we present an overview of EAD after LDLT and have attempted to present balanced points of view on all its aspects, such as definitions, pathogenesis, risk factors, predictive markers, and management. The review aims to broadly overview the nature and extent of ongoing research evidence on this complex topic and inform practice in the field by identifying key concepts and knowledge gaps and highlighting areas that require further inquiry.

International Liver Transplantation Society/Society for Advancement of Transplant Anesthesia Consensus Statement on Essential Attributes of a Liver Transplant Anesthesiologist

BACKGROUND

We sought to establish consensus on the essential skills, knowledge, and attributes that a liver transplant (LT) anesthesiologist should possess in a bid to help guide the further training process.

METHODS

Consensus was achieved via a modified Delphi methodology, surveying 15 identified international experts in the fields of LT anesthesia and critical care.

RESULTS

Key competencies were identified in preoperative management and optimization of a potential LT recipient; intraoperative management, including hemodynamic monitoring; coagulation and potential crisis management; and postoperative intensive and enhanced recovery care.

CONCLUSIONS

This article provides an essential guide to competency-based training of an LT anesthesiologist.

Low C-reactive Protein and Urea Distinguish Primary Nonfunction From Early Allograft Dysfunction Within 48 Hours of Liver Transplantation

Primary nonfunction (PNF) is a life-threatening complication of liver transplantation (LT), but in the early postoperative period, it can be difficult to differentiate from early allograft dysfunction (EAD). The aim of this study was to determine if serum biomarkers can distinguish PNF from EAD in the initial 48 h following LT.

Materials and Methods

A retrospective study of adult patients that underwent LT between January 2010 and April 2020 was performed. Clinical parameters, absolute values and trends of C-reactive protein (CRP), blood urea, creatinine, liver function tests, platelets, and international normalized ratio in the initial 48 h after LT were compared between the EAD and PNF groups.

Results

There were 1937 eligible LTs, with PNF and EAD occurring in 38 (2%) and 503 (26%) patients, respectively. A low serum CRP and urea were associated with PNF. CRP was able to differentiate between the PNF and EAD on postoperative day (POD)1 (20 versus 43 mg/L; P < 0.001) and POD2 (24 versus 77; P < 0.001). The area under the receiver operating characteristic curve (AUROC) of POD2 CRP was 0.770 (95% confidence interval [CI] 0.645-0.895). The urea value on POD2 (5.05 versus 9.0 mmol/L; P = 0.002) and trend of POD2:1 ratio (0.71 versus 1.32 mmol/L; P < 0.001) were significantly different between the groups. The AUROC of the change in urea from POD1 to 2 was 0.765 (95% CI 0.645-0.885). Aspartate transaminase was significantly different between the groups, with an AUROC of 0.884 (95% CI 0.753-1.00) on POD2.

Discussion

The biochemical profile immediately following LT can distinguish PNF from EAD; CRP, urea, and aspartate transaminase are more effective than ALT and bilirubin in distinguishing PNF from EAD in the initial postoperative 48 h. Clinicians should consider the values of these markers when making treatment decisions.

Impact of Hypothermic Oxygenated Machine Perfusion on Hepatocellular Carcinoma Recurrence after Liver Transplantation

BACKGROUND

Machine perfusion may be able to mitigate ischemia-reperfusion injury (IRI), which increases hepatocellular carcinoma (HCC) recurrence after liver transplantation (LT). This study aimed to investigate the impact of dual-hypothermic oxygenated machine perfusion (D-HOPE) on HCC recurrence in LT.

METHODS

A single-center retrospective study was conducted from 2016 to 2020. Pre- and postoperative data of HCC patients undergoing LT were analyzed. Recipients of a D-HOPE-treated graft were compared to those of livers preserved using static cold storage (SCS). The primary endpoint was recurrence-free survival (RFS).

RESULTS

Of 326 patients, 246 received an SCS-preserved liver and 80 received a D-HOPE-treated graft (donation after brain death (DBD), n = 66; donation after circulatory death (DCD), n = 14). Donors of D-HOPE-treated grafts were older and had higher BMI. All DCD donors were treated by normothermic regional perfusion and D-HOPE. The groups were comparable in terms of HCC features and estimated 5-year RFS according to the Metroticket 2.0 model. D-HOPE did not reduce HCC recurrence (D-HOPE 10%; SCS 8.9%; p = 0.95), which was confirmed using Bayesian model averaging and inverse probability of treatment weighting-adjusted RFS analysis. Postoperative outcomes were comparable between groups, except for lower AST and ALT peak in the D-HOPE group.

CONCLUSIONS

In this single-center study, D-HOPE did not reduce HCC recurrence but allowed utilizing livers from extended criteria donors with comparable outcomes, improving access to LT for patients suffering from HCC.

Predicting Early Graft Dysfunction and Mortality After Liver Transplant Using the De Ritis Ratio

BACKGROUND

Predicting complications after liver transplantation (LT) remains challenging. We propose incorporating the De Ritis ratio (DRR), a widely known parameter of liver dysfunction, into current or future scoring models to predict early allograft dysfunction (EAD) and mortality after LT.

METHODS

A retrospective chart review was conducted on 132 adults receiving a deceased donor LT from April 2015 to March 2020 and their matching donors. Donor variables, postoperative liver function, and DRR were correlated with the occurrence of EAD, post-transplant complications expressed by the Clavien-Dindo score, and 30-day mortality as outcome variables.

RESULTS

Early allograft dysfunction was observed in 26.5% of patients and 7.6% of patients who died within 30 days after transplant. Recipients were more likely to experience EAD when receiving grafts from donation after circulatory death (P = .04), donor risk index (DRI) >2 (P = .006), ischemic injury at time-zero biopsy (P = .02), longer secondary warm ischemia time (P < .05), or higher Clavien-Dindo scores (IIIb-V; P < .001). The DRI, total bilirubin, and DRR on postoperative day 5 yielded significant associations with the primary outcomes and were used to develop the Gala-Lopez score using a weighted scoring model. This accurately predicted EAD, high Clavien-Dindo, and 30-day mortality in 75%, 81%, and 64% of patients.

CONCLUSION

Including recipient and donor variables in predictive models, and for the first time DRR, as a constituent, should be regarded to predict EAD, severe complications, and 30-day mortality post-LT. Further studies will be required to validate the present findings and their applicability when using normothermic regional and machine perfusion technologies.

Early γGT and bilirubin levels as biomarkers for regeneration and outcomes in damaged bile ducts after liver transplantation

BACKGROUND

Early patient and allograft survival after liver transplantation (LT) depend primarily on parenchymal function, but long-term allograft success relies often on biliary-tree function. We examined parameters related to cholangiocyte damage that predict poor long-term LT outcomes after donation after brain death (DBD).

METHODS

Sixty bile ducts (BD) were assessed by a BD damage-score and divided into groups with "major" BD-damage (n = 33) and "no relevant" damage (n = 27) during static cold storage. Patients with "major" BD damage were further investigated by measuring biliary excretion parameters in the first 14 days post-LT (followed-up for 60-months).

RESULTS

Patients who received LT showing "major" BD damage had significantly worse long-term patient survival, versus grafts with "no relevant" damage (p = .03). When "major" BD damage developed, low bilirubin levels (p = .012) and high gamma-glutamyl transferase (GGT)/bilirubin ratio (p = .0003) were evident in the early post-LT phase (7-14 days) in patients who survived (> 60 months), compared to those who did not. "High risk" patients with bile duct damage and low GGT/bilirubin ratio had significantly shorter overall survival (p < .0001).

CONCLUSIONS

Once "major" BD damage occurs, a high GGT/bilirubin ratio in the early post-operative phase is likely indicator of liver and cholangiocyte regeneration, and thus a harbinger of good overall outcomes. "Major" BD damage without markers of regeneration identifies LT patients that could benefit from future repair therapies.

Validation of risk scores for allograft failure after liver transplantation in Germany: a retrospective cohort analysis

A growing number of clinical risk scores have been proposed to predict allograft failure after liver transplantation. However, validation of currently available scores in the Eurotransplant region is still lacking. We aimed to analyze all clinically relevant donor and recipient risk scores on a large German liver transplantation data set and performed a retrospective cohort analysis of liver transplantations performed at the Charité-Universitätsmedizin Berlin from January 2007 until December 2021 with organs from donation after brain death. We analyzed 9 previously published scores in 906 liver transplantations [Eurotransplant donor risk index (ET-DRI/DRI), donor age and model for end-stage liver disease (D-MELD), balance of risk (BAR), early allograft dysfunction (EAD), model for early allograft function (MEAF), liver graft assessment following transplantation (L-GrAFT7), early allograft failure simplified estimation (EASE), and a score by Rhu and colleagues). The EASE score had the best predictive value for 3-month, 6-month, and 12-month graft survival with a c-statistic of 0.8, 0.77, and 0.78, respectively. In subgroup analyses, the EASE score was suited best for male recipients with a high-MELD (>25) and an EAD organ. Scores only based on pretransplant data performed worse compared to scores including postoperative data (eg, ET-DRI vs. EAD, p<0.001 at 3-month graft survival). Out of these, the BAR score performed best with a c-statistic of 0.6. This a comprehensive comparison of the clinical utility of risk scores after liver transplantation. The EASE score sufficiently predicted 12-month graft and patient survival. Despite a relatively complex calculation, the EASE score provides significant prognostic value for patients and health care professionals in the Eurotransplant region.

Characterization of hepatic steatosis using controlled attenuation parameter and MRI-derived proton density fat fraction in living donor liver transplantation

BACKGROUND

The increasingly favorable outcomes of live donor liver transplant warrant development of screening techniques to expand current donor pool. Transient elastography (TE) with controlled attenuation parameter (CAP) is accessible and has promising diagnostic performance in non-obese individuals. Here, we demonstrate its utility in grading donor steatosis for risk assessment in living liver donors (LLD).

STUDY DESIGN

In a prospective study of LLD and recipients, accuracy was determined using MRI-derived proton density fat fraction (PDFF) as reference.

RESULTS

One hundred and one LLD underwent TE, 95 of whom had available PDFF. Median CAP and MRI-PDFF were 233 dB/m (206-270) and 2.9% (2.3-4.0), respectively. A CAP threshold of 270 dB/m captured all steatosis which was present in 13 (13%) LLD (AUROC .942, 100% sensitivity and 83% specificity). Performance further improved when excluding obese LLD and limiting analysis to M-probe (AUROC .971 and .974, respectively, with 87% specificity). There was no difference in CAP and MRI-PDFF between LLD and nondonors (P = .26 and .21, respectively). Early allograft dysfunction was observed in one recipient (CAP 316, PDFF 9.5%), zero underwent retransplant, and one died from sepsis.

CONCLUSION

The specific role of CAP in living liver donation warrants further study, beginning with its use as screening tool across peripheral clinics.

Graft weight integration in the early allograft dysfunction formula improves the prediction of early graft loss after liver transplantation

The role of the graft-to-recipient weight ratio (GRWR) in adult liver transplantation (LT) has been poorly investigated so far. The aim is to evaluate the contribution of the GRWR to the well-recognized early allograft dysfunction (EAD) model (i.e., Olthoff model) for the prediction of 90-day graft loss after LT in adults. Three hundred thirty-one consecutive adult patients undergoing LT between 2009 and 2018 at Tor Vergata and Sapienza University in Rome, Italy, served as the Training-Set. The Validation-Set included 123 LTs performed at the Erasmus Medical Center, Rotterdam, the Netherlands. The mEAD model for 90-day graft loss included the following variables: GRWR [Formula: see text] 1.57 = 2.5, GRWR [Formula: see text] 2.13 = 2.5, total bilirubin ≥ 10.0 mg/dL = 2.0, INR ≥ 1.60 = 2.3, and aminotransferase > 2000 IU/L = 2.2. The mEAD model showed an AUC = 0.74 (95%CI = 0.66-0.82; p < 0.001) and AUC = 0.68 (95%CI = 0.58-0.88; p = 0.01) in the Training-Set and Validation-Set, respectively, outperforming conventional EAD in both cohorts (Training-Set: AUC = 0.64, 95%CI = 0.57-0.72; p = 0.001; Validation-Set: AUC = 0.52, 95%CI = 0.35-0.69, p = 0.87). Incorporation of graft weight in a composite multivariate model allowed for better prediction of patients who presented an aminotransferase peak > 2000 IU/L after LT (OR = 2.39, 95%CI = 1.47-3.93, p = 0.0005). The GRWR is important in determining early graft loss after adult LT, and the mEAD model is a useful predictive tool in this perspective, which may assist in improving the graft allocation process.

The Edge of Unknown: Postoperative Critical Care in Liver Transplantation

Perioperative care of patients undergoing liver transplantation (LT) is very complex. Metabolic derangements, hypothermia, coagulopathy and thromboses, severe infections, and graft dysfunction can affect outcomes. In this manuscript, we discuss several perioperative problems that can be encountered in LT recipients. The authors present the most up-to-date information regarding predicting and treating hemodynamic instability, coagulation monitoring and management, postoperative ventilation strategies and early extubation, management of infections, and ESLD-related pulmonary complications. In addition, early post-transplant allograft dysfunction will be discussed.

Hyperspectral Imaging as a Tool for Viability Assessment During Normothermic Machine Perfusion of Human Livers: A Proof of Concept Pilot Study

Normothermic machine perfusion (NMP) allows for ex vivo viability and functional assessment prior to liver transplantation (LT). Hyperspectral imaging represents a suitable, non-invasive method to evaluate tissue morphology and organ perfusion during NMP. Liver allografts were subjected to NMP prior to LT. Serial image acquisition of oxygen saturation levels (StO2), organ hemoglobin (THI), near-infrared perfusion (NIR) and tissue water indices (TWI) through hyperspectral imaging was performed during static cold storage, at 1h, 6h, 12h and at the end of NMP. The readouts were correlated with perfusate parameters at equivalent time points. Twenty-one deceased donor livers were included in the study. Seven (33.0%) were discarded due to poor organ function during NMP. StO2 (p < 0.001), THI (p < 0.001) and NIR (p = 0.002) significantly augmented, from static cold storage (pre-NMP) to NMP end, while TWI dropped (p = 0.005) during the observational period. At 12-24h, a significantly higher hemoglobin concentration (THI) in the superficial tissue layers was seen in discarded, compared to transplanted livers (p = 0.036). Lactate values at 12h NMP correlated negatively with NIR perfusion index between 12 and 24h NMP and with the delta NIR perfusion index between 1 and 24h (rs = -0.883, p = 0.008 for both). Furthermore, NIR and TWI correlated with lactate clearance and pH. This study provides first evidence of feasibility of hyperspectral imaging as a potentially helpful contact-free organ viability assessment tool during liver NMP.

Outcome of liver transplantation with grafts from brain-dead donors treated with dual hypothermic oxygenated machine perfusion, with particular reference to elderly donors

Prompted by the utilization of extended criteria donors, dual hypothermic oxygenated machine perfusion (D-HOPE) was introduced in liver transplantation to improve preservation. When donors after neurological determination of death (DBD) are used, D-HOPE effect on graft outcomes is unclear. To assess D-HOPE value in this setting and to identify ideal scenarios for its use, data on primary adult liver transplant recipients from January 2014 to April 2021 were analyzed using inverse probability of treatment weighting, comparing outcomes of D-HOPE-treated grafts (n = 121) with those preserved by static cold storage (n = 723). End-ischemic D-HOPE was systematically applied since November 2017 based on donor and recipient characteristics and transplant logistics. D-HOPE use was associated with a significant reduction of early allograft failure (OR: 0.24; 0.83; p = .024), grade ≥3 complications (OR: 0.57; p = .046), comprehensive complication index (-7.20 points; p = .003), and improved patient and graft survival. These results were confirmed in the subset of elderly donors (>75-year-old). Although D-HOPE did not reduce the incidence of biliary complications, its use was associated with a reduced severity of ischemic cholangiopathy. In conclusion, D-HOPE improves postoperative outcomes and reduces early allograft loss in extended criteria DBD grafts.

The Need to Update Endpoints and Outcome Analysis in the Rapidly Changing Field of Liver Transplantation

Liver transplantation (LT) survival rates have continued to improve over the last decades, mostly due to the reduction of mortality early after transplantation. The advancement is facilitating a liberalization of access to LT, with more patients with higher risk profiles being added to the waiting list. At the same time, the persisting organ shortage fosters strategies to rescue organs of high-risk donors. This is facilitated by novel technologies such as machine perfusion. Owing to these developments, reconsideration of the current and emerging endpoints for the assessment of the efficacy of existing and new therapies is warranted. While conventional early endpoints in LT have focused on the damage induced to the parenchyma, the fate of the bile duct and the recurrence of the underlying disease have a stronger impact on the long-term outcome. In light of this evolving landscape, we here attempt to reflect on the appropriateness of the currently used endpoints in the field of LT trials.

Perfusate Enzymes and Platelets Indicate Early Allograft Dysfunction After Transplantation of Normothermically Preserved Livers

BACKGROUND

Normothermic machine perfusion (NMP) has become a clinically established tool to preserve livers in a near-physiological environment. However, little is known about the predictive value of perfusate parameters toward the outcomes after transplantation.

METHODS

Fifty-five consecutive NMP livers between 2018 and 2019 were included. All of the livers were perfused on the OrganOx metra device according to an institutional protocol. Transplant and perfusion data were collected prospectively.

RESULTS

Forty-five livers were transplanted after NMP. Five livers stem from donors after circulatory death and 31 (68.9%) from extended criteria donors. Mean (SD) cold ischemia time was 6.4 (2.3) h; mean (SD) total preservation time was 21.4 (7.1) h. Early allograft dysfunction (EAD) occurred in 13 of 45 (28.9%) patients. Perfusate aspartate aminotransferase (P = 0.008), alanine aminotransferase (P = 0.006), lactate dehydrogenase (P = 0.007) and their development over time, alkaline phosphatase (P = 0.013), and sodium (P = 0.016) correlated with EAD. Number of perfusate platelets correlated with cold ischemia time duration and were indicative for the occurrence of EAD. Moreover, von Willebrand Factor antigen was significantly higher in perfusates of EAD livers (P < 0.001), and Δ von Willebrand factor antigen correlated with EAD. Although perfusate lactate and glucose had no predictive value, EAD was more likely to occur in livers with lower perfusate pH (P = 0.008). ΔPerfusate alkaline phosphatase, Δperfusate aspartate aminotransferase, Δperfusate alanine aminotransferase, and Δperfusate lactate dehydrogenase correlated closely with model for early allograft function but not liver graft assessment following transplantation risk score. Bile parameters correlated with extended criteria donor and donor risk index.

CONCLUSIONS

Biomarker assessment during NMP may help to predict EAD after liver transplantation. The increase of transaminases and lactate dehydrogenase over time as well as platelets and vWF antigen are important factors indicative for EAD.

Over 30 Years of Pediatric Liver Transplantation at the Charité-Universitätsmedizin Berlin

Background: Pediatric liver transplantation (LT) is the treatment of choice for children with end-stage liver disease and in certain cases of hepatic malignancies. Due to low case numbers, a technically demanding procedure, the need for highly specialized perioperative intensive care, and immunological, as well as infectious, challenges, the highest level of interdisciplinary cooperation is required. The aim of our study was to analyze short- and long-term outcomes of pediatric LT in our center. Methods: We conducted a retrospective single-center analysis of all liver transplantations in pediatric patients (≤16 years) performed at the Department of Surgery, Charité – Universitätsmedizin Berlin between 1991 and 2021. Three historic cohorts (1991–2004, 2005–2014 and 2015–2021) were defined. Graft- and patient survival, as well as perioperative parameters were analyzed. The study was approved by the institutional ethics board. Results: Over the course of the 30-year study period, 212 pediatric LTs were performed at our center. The median patient age was 2 years (IQR 11 years). Gender was equally distributed (52% female patients). The main indications for liver transplantation were biliary atresia (34%), acute hepatic necrosis (27%) and metabolic diseases (13%). The rate of living donor LT was 25%. The median cold ischemia time for donation after brain death (DBD) LT was 9 h and 33 min (IQR 3 h and 46 min). The overall donor age was 15 years for DBD donors and 32 years for living donors. Overall, respective 1, 5, 10 and 30-year patient and graft survivals were 86%, 82%, 78% and 65%, and 78%, 74%, 69% and 55%. One-year patient survival was 85%, 84% and 93% in the first, second and third cohort, respectively (p = 0.14). The overall re-transplantation rate was 12% (n = 26), with 5 patients (2%) requiring re-transplantation within the first 30 days. Conclusion: The excellent long-term survival over 30 years showcases the effectiveness of liver transplantation in pediatric patients. Despite a decrease in DBD organ donation, patient survival improved, attributed, besides refinements in surgical technique, mainly to improved interdisciplinary collaboration and management of perioperative complications.

Prolonged dual hypothermic oxygenated machine preservation (DHOPE-PRO) in liver transplantation: study protocol for a stage 2, prospective, dual-arm, safety and feasibility clinical trial

Introduction

End-ischaemic preservation of a donor liver by dual hypothermic oxygenated machine perfusion (DHOPE) for 2 hours prior to transplantation is sufficient to mitigate ischaemia-reperfusion damage and fully restore cellular energy levels. Clinical studies have shown beneficial outcomes after transplantation of liver grafts preserved by DHOPE compared with static cold storage. In addition to graft reconditioning, DHOPE may also be used to prolong preservation time, which could facilitate logistics for allocation and transplantation globally.

Methods and analysis

This is a prospective, pseudo-randomised, dual-arm, IDEAL-D (Idea, Development, Exploration, Assessment, Long term study-Framework for Devices) stage 2 clinical device trial designed to determine safety and feasibility of prolonged DHOPE (DHOPE-PRO). The end-time of the donor hepatectomy will determine whether the graft will be assigned to the intervention (16:00–3:59 hour) or to the control arm (4:00–15:59 hour). In total, 36 livers will be included in the study. Livers in the intervention group (n=18) will undergo DHOPE-PRO (≥4 hours) until implantation the following morning, whereas livers in the control group (n=18) will undergo regular DHOPE (2 hours) prior to implantation. The primary endpoint of this study is a composite of the occurrence of all (serious) adverse events during DHOPE and up to 30 days after liver transplantation.

Ethics and dissemination

The protocol was approved by the Medical Ethical Committee of Groningen, METc2020.126 in June 2020, and the study was registered in the Netherlands National Trial Registry (https://www.trialregister.nl/) prior to initiation.

Trial registration number

NL8740.

Reassessment of Relevance and Predictive Value of Parameters Indicating Early Graft Dysfunction in Liver Transplantation: AST Is a Weak, but Bilirubin and INR Strong Predictors of Mortality

Introduction: Early graft dysfunction (EAD) complicates liver transplantation (LT). The aim of this analysis was to discriminate between the weight of each variable as for its predictive value toward patient and graft survival. Methods: We reviewed all LT performed at the Medical University of Innsbruck between 2007 and 2018. EAD was recorded when one of the following criteria was present: (i) aspartate aminotransferase (AST) levels >2,000 IU/L within the first 7 days, (ii) bilirubin levels ≥10mg/dL or (iii) international normalized ratio (INR) ≥1.6 on postoperative day 7. Results: Of 616 LT, 30.7% developed EAD. Patient survival did not differ significantly (P = 0.092; log rank-test = 2.87), graft survival was significantly higher in non-EAD patients (P = 0.008; log rank-test = 7.13). Bilirubin and INR on postoperative day 7 were identified as strong mortality predictors (Bilirubin HR = 1.71 [1.34, 2.16]; INR HR = 2.69 [0.51, 14.31]), in contrast to AST (HR = 0.91 [0.75, 1.10]). Similar results were achieved for graft loss estimation. A comparison with the Model for Early Allograft Function (MEAF) and the Liver Graft Assessment Following Transplantation (L-GrAFT) score identified a superior discrimination potential but lower specificity. Conclusion: Contrarily to AST, bilirubin and INR have strong predictive capacity for patient and graft survival. This fits well with the understanding, that bile duct injury and deprivation of synthetic function rather than hepatocyte injury are key factors in LT.

Prediction of Graft Survival Post-liver Transplantation by L-GrAFT Risk Score Model, EASE Score, MEAF Scoring, and EAD

Background: Early allograft dysfunction (EAD) is correlated with poor patient or graft survival in liver transplantation. However, the power of distinct definitions of EAD in prediction of graft survival is unclear. Methods: This retrospective, single-center study reviewed data of 677 recipients undergoing orthotopic liver transplant between July 2015 and June 2020. The following EAD definitions were compared: liver graft assessment following transplantation (L-GrAFT) risk score model, early allograft failure simplified estimation score (EASE), model for early allograft function (MEAF) scoring, and Olthoff criteria. Risk factors for L-GrAFT₇ high risk group were evaluated with univariate and multivariable logistic regression analysis. Results: L-GrAFT₇ had a satisfied C-statistic of 0.87 in predicting a 3-month graft survival which significantly outperformed MEAF (C-statistic = 0.78, P = 0.01) and EAD (C-statistic = 0.75, P < 0.001), respectively. L-GrAFT₁₀, EASE was similar to L-GrAFT₇, and they had no statistical significance in predicting survival. Laboratory model for end-stage liver disease score and cold ischemia time are risk factors of L-GrAFT₇ high-risk group. Conclusion: L-GrAFT₇ risk score is capable for better predicting the 3-month graft survival than the MEAF and EAD in a Chinese cohort, which might standardize assessment of early graft function and serve as a surrogate endpoint in clinical trial.

Post-Liver Transplant Early Allograft Dysfunction Modifies the Effect of Pre-Liver Transplant Renal Dysfunction on Post-Liver Transplant Survival

Pre-liver transplantation (LT) renal dysfunction is associated with poor post-LT survival. We studied whether early allograft dysfunction (EAD) modifies this association. Data on 2,856 primary LT recipients who received a transplant between 1998 and 2018 were retrospectively reviewed. Patients who died within the first post-LT week or received multiorgan transplants and previous LT recipients were excluded. EAD was defined as (1) total bilirubin ≥ 10 mg/dL on postoperative day (POD) 7, (2) international normalized ratio ≥1.6 on POD 7, and/or (3) alanine aminotransferase or aspartate aminotransferase ≥2000 IU/mL in the first postoperative week. Pre-LT renal dysfunction was defined as serum creatinine >1.5 mg/dL or on renal replacement therapy at LT. Patients were divided into 4 groups according to pre-LT renal dysfunction and post-LT EAD development. Recipients who had both pre-LT renal dysfunction and post-LT EAD had the worst unadjusted 1-year, 3-year, and 5-year post-LT patient and graft survival, whereas patients who had neither renal dysfunction nor EAD had the best survival (P < 0.001). After adjusting for multiple factors, the risk of death was significantly higher only in those with both pre-LT renal dysfunction and post-LT EAD (adjusted hazard ratio [aHR], 2.19; 95% confidence interval [CI], 1.58-3.03; P < 0.001), whereas those with renal dysfunction and no EAD had a comparable risk of death to those with normal kidney function at LT (aHR, 1.12; 95% CI, 0.86-1.45; P = 0.41). Results remained unchanged when pre-LT renal dysfunction was redefined using different glomerular filtration rate cutoffs. Pre-LT renal dysfunction negatively impacts post-LT survival only in patients who develop EAD. Livers at higher risk of post-LT EAD should be used with caution in recipients with pre-LT renal dysfunction.

Early Allograft Dysfunction and Complications in DCD Liver Transplantation: Expert Consensus Statements From the International Liver Transplantation Society

Livers for transplantation from donation after circulatory death donors are relatively more prone to early and ongoing alterations in graft function that might ultimately lead to graft loss and even patient death. In consideration of this fact, this working group of the International Liver Transplantation Society has performed a critical evaluation of the medical literature to create a set of statements regarding the assessment of early allograft function/dysfunction and complications arising in the setting of donation after circulatory death liver transplantation.

The Role of Ex Situ Hypothermic Oxygenated Machine Perfusion and Cold Preservation Time in Extended Criteria Donation After Circulatory Death and Donation After Brain Death

Hypothermic oxygenated machine perfusion (HOPE) has the potential to counterbalance the detrimental consequences of cold and warm ischemia time (WIT) in both donation after brain death (DBD) and donation after circulatory death (DCD). Herein we investigated the protective effects of HOPE in extended criteria donor (ECD) DBD and overextended WIT DCD grafts. The present retrospective case series included 50 livers subjected to end-ischemic HOPE or dual DHOPE in 2 liver transplantation (LT) centers from January 2018 to December 2019. All DCD donors were subjected to normothermic regional perfusion before organ procurement. Results are expressed as median (interquartile range [IQR]). In the study period, 21 grafts were derived from overextended WIT DCD donors (total WIT 54 [IQR, 40-60] minutes and 75% classified as futile), whereas 29 were from ECD DBD. A total of 3 biliary complications and 1 case of ischemia-type biliary lesion were diagnosed. The rate of early allograft dysfunction (EAD) was 20%, and those patients had higher Comprehensive Complication Index scores. Through a changing point analysis, cold preservation time >9 hours was associated with prolonged hospital stays (P = 0.02), higher rates of EAD (P = 0.009), and worst post-LT complications (P = 0.02). Logistic regression analyses indicated a significant relationship between cold preservation time and EAD. No differences were shown in terms of the early post-LT results between LTs performed with DCD and DBD. Overall, our data are fully comparable with benchmark criteria in LT. In conclusion, the application of DHOPE obtained satisfactory and promising results using ECD-DBD and overextended DCD grafts. Our findings indicate the need to reduce cold preservation time also in the setting of DHOPE, particularly for grafts showing poor quality.