Validation of a current definition of early allograft dysfunction in liver transplant recipients and analysis of risk factors

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.

Effect of Hemodynamic Monitoring Systems on Short-Term Outcomes after Living Donor Liver Transplantation

Background and Objectives: To evaluate the effects of the pulse index continuous cardiac output and MostCare Pressure Recording Analytical Method hemodynamic monitoring systems on short-term graft and patient outcomes during living donor liver transplantation in adult patients. Materials and Methods: Overall, 163 adult patients who underwent living donor liver transplantation between January 2018 and March 2022 and met the study inclusion criteria were divided into two groups based on the hemodynamic monitoring systems used during surgery: the MostCare Pressure Recording Analytical Method group (n = 73) and the pulse index continuous cardiac output group (n = 90). The groups were compared with respect to preoperative clinicodemographic features (age, sex, body mass index, graft-to-recipient weight ratio, and Model for End-stage Liver Disease score), intraoperative clinical characteristics, and postoperative biochemical parameters (aspartate aminotransferase, alanine aminotransferase, total bilirubin, direct bilirubin, prothrombin time, international normalized ratio, and platelet count). Results: There were no significant between-group differences with respect to recipient age, sex, body mass index, graft-to-recipient weight ratio, Child, Model for End-stage Liver Disease score, ejection fraction, systolic pulmonary artery pressure, surgery time, anhepatic phase, cold ischemia time, warm ischemia time, erythrocyte suspension use, human albumin use, crystalloid use, urine output, hospital stay, and intensive care unit stay. However, there was a significant difference in fresh frozen plasma use (p < 0.001) and platelet use (p = 0.037). Conclusions: The clinical and biochemical outcomes are not significantly different between pulse index continuous cardiac output and MostCare Pressure Recording Analytical Method as hemodynamic monitoring systems in living donor liver transplantation. However, the MostCare Pressure Recording Analytical Method is more economical and minimally invasive.

Serum from patients with cirrhosis undergoing liver transplantation induces permeability in human pulmonary microvascular endothelial cells ex vivo

Introduction

Patients with cirrhosis undergoing liver transplantation frequently exhibit systemic inflammation, coagulation derangements, and edema, indicating endothelial dysfunction. This syndrome may worsen after ischemia-reperfusion injury of the liver graft, coincident with organ dysfunction that worsens patient outcomes. Little is known about changes in endothelial permeability during liver transplantation. We hypothesized that sera from these patients would increase permeability in cultured human endothelial cells ex vivo.

Methods

Adults with cirrhosis presenting for liver transplantation provided consent for blood collection during surgery. Sera were prepared at five time points spanning the entire operation. The barrier function of human pulmonary microvascular endothelial cells in culture was assessed by transendothelial resistance measured using the ECIS ZΘ system. Confluent cells from two different endothelial cell donors were stimulated with human serum from liver transplant patients. Pooled serum from healthy men and purified inflammatory agonists served as controls. The permeability response to serum was quantified as the area under the normalized resistance curve. Responses were compared between time points and analyzed for associations with clinical characteristics of liver transplant patients and their grafts.

Results

Liver transplant sera from all time points during surgery-induced permeability in both endothelial cell lines. The magnitude of permeability change was heterogeneous between patients, and there were differences in the effects of sera on the two endothelial cell lines. In one of the cell lines, the severity of liver disease was associated with greater permeability at the start of surgery. In the same cell line, serum collected 15 min after liver reperfusion induced significantly more permeability as compared to that collected at the start of surgery. Early postreperfusion sera from patients undergoing living donor transplants induced more permeability than sera from deceased donor transplants. Sera from two exemplary cases of patients on preoperative dialysis, and one patient with an unexpectedly long warm ischemia time of the liver graft, induced exaggerated and prolonged endothelial permeability.

Discussion

Serum from patients with cirrhosis undergoing liver transplantation induces permeability of cultured human pulmonary microvascular endothelial cells. Increased endothelial permeability during liver transplantation may contribute to organ injury and present a target for future therapeutics.

Phase I clinical trial of the feasibility and safety of direct peritoneal resuscitation in liver transplantation

BACKGROUND

Direct peritoneal resuscitation (DPR) is associated with improved outcomes in trauma. Animal models suggest DPR has favorable effects on the liver. We sought to evaluate its safety and assess for improved outcomes in liver transplantation (LT).

METHODS

LT patients with renal dysfunction and/or obesity were enrolled in a phase-I clinical trial. DPR lasted 8-24 ​h depending on postoperative disposition. Primary outcome was percent of patients completing DPR. Secondary outcomes evaluated complications. Controls with either obesity (control-1) or both risk factors (obesity ​+ ​renal dysfunction, control-2) were analyzed.

RESULTS

Fifteen patients were enrolled (seven with both criteria and eight with obesity alone). DPR was completed in 87 ​% of patients, with one meeting stopping criteria. Controls included 45 (control-1) and 24 (control-2) patients. Return to operating room, graft loss, and late infections were lower with DPR.

CONCLUSION

DPR appears to be safe in closed abdomens following LT, warranting a follow-up phase-II trial to assess efficacy.

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.

Viability assessment and transplantation of extended criteria donor liver grafts using normothermic machine perfusion

BACKGROUND

The scarcity of available liver grafts necessitates the use of organs from extended criteria donors, a practice associated with an increased risk of graft failure. A notable percentage of deceased donor liver allografts are rejected due to subjective criteria. Normothermic machine perfusion holds promise for introducing objective parameters into this decision-making process. The aim of this study was to compare the outcomes of standard criteria and extended criteria donor allografts after liver transplantation, following viability assessment, using normothermic machine perfusion.

METHODS

Liver allografts preserved by normothermic machine perfusion before liver transplantation at the University Hospital of Münster were retrospectively analyzed. Organs were stratified according to the Eurotransplant Donor Risk Index. In total, 101 liver grafts were included in this study and divided into 2 groups: (1) standard criteria donors with a Donor Risk Index <1.8 (DRI-low) and (2) extended criteria donors with a Donor Risk Index ≥1.8 (DRI-high).

RESULTS

An increased risk profile of donor livers, as assessed by the Eurotransplant Donor Risk Index, did not correlate with patient or graft survival. High-risk liver grafts were effectively transplanted into recipients with different risk levels after viability assessment by normothermic machine perfusion. However, the recipients' model for end-stage liver disease scores showed a significant association with both overall patient and graft survival.

CONCLUSION

The use of normothermic machine perfusion for viability assessment allows safe transplantation of high-risk donor livers and effectively addresses the disparity between donor liver availability and transplantation demand.

Portal vein arterialization in 25 liver transplant recipients: A Latin American single-center experience

BACKGROUND

Portal vein arterialization (PVA) has been used in liver transplantation (LT) to maximize oxygen delivery when arterial circulation is compromised or has been used as an alternative reperfusion technique for complex portal vein thrombosis (PVT). The effect of PVA on portal perfusion and primary graft dysfunction (PGD) has not been assessed.

AIM

To examine the outcomes of patients who required PVA in correlation with their LT procedure.

METHODS

All patients receiving PVA and LT at the Fundacion Santa Fe de Bogota between 2011 and 2022 were analyzed. To account for the time-sensitive effects of graft perfusion, patients were classified into two groups: prereperfusion (pre-PVA), if the arterioportal anastomosis was performed before graft revascularization, and postreperfusion (post-PVA), if PVA was performed afterward. The pre-PVA rationale contemplated poor portal hemodynamics, severe vascular steal, or PVT. Post-PVA was considered if graft hypoperfusion became evident. Conservative interventions were attempted before PVA.

RESULTS

A total of 25 cases were identified: 15 before and 10 after graft reperfusion. Pre-PVA patients were more affected by diabetes, decompensated cirrhosis, impaired portal vein (PV) hemodynamics, and PVT. PGD was less common after pre-PVA (20.0% vs 60.0%) (P = 0.041). Those who developed PGD had a smaller increase in PV velocity (25.00 cm/s vs 73.42 cm/s) (P = 0.036) and flow (1.31 L/min vs 3.34 L/min) (P = 0.136) after arterialization. Nine patients required PVA closure (median time: 62 d). Pre-PVA and non-PGD cases had better survival rates than their counterparts (56.09 months vs 22.77 months and 54.15 months vs 31.91 months, respectively).

CONCLUSION

This is the largest report presenting PVA in LT. Results suggest that pre-PVA provides better graft perfusion than post-PVA. Graft hyperperfusion could play a protective role against PGD.

Calcineurin Inhibitor in NEuRoloGically deceased donors to decrease kidney delayed graft function study: study protocol of the CINERGY Pilot randomised controlled trial

INTRODUCTION

Most solid organ transplants originate from donors meeting criteria for death by neurological criteria (DNC). Within the organ donor, physiological responses to brain death increase the risk of ischaemia reperfusion injury and delayed graft function. Donor preconditioning with calcineurin inhibition may reduce this risk.

METHODS AND ANALYSIS

We designed a multicentre placebo-controlled pilot randomised trial involving nine organ donation hospitals and all 28 transplant programmes in the Canadian provinces of Ontario and Québec. We planned to enrol 90 DNC donors and their approximately 324 organ recipients, totalling 414 participants. Donors receive an intravenous infusion of either tacrolimus 0.02 mg/kg over 4 hours prior to organ retrieval, or a matching placebo, while monitored in an intensive care unit for any haemodynamic changes during the infusion. Among all study organ recipients, we record measures of graft function for the first 7 days in hospital and we will record graft survival after 1 year. We examine the feasibility of this trial with respect to the proportion of all eligible donors enrolled and the proportion of all eligible transplant recipients consenting to receive a CINERGY organ transplant and to allow the use of their health data for study purposes. We will report these feasibility outcomes as proportions with 95% CIs. We also record any barriers encountered in the launch and in the implementation of this trial with detailed source documentation.

ETHICS AND DISSEMINATION

We will disseminate trial results through publications and presentations at participating sites and conferences. This study has been approved by Health Canada (HC6-24-c241083) and by the Research Ethics Boards of all participating sites and in Québec (MP-31-2020-3348) and Clinical Trials Ontario (Project #3309).

TRIAL REGISTRATION NUMBER

NCT05148715.

Cross-species metabolomic profiling reveals phosphocholine-mediated liver protection from cold and ischemia/reperfusion

Cold and ischemia/reperfusion (IR)-associated injuries are seemingly inevitable during liver transplantation and hepatectomy. Because Syrian hamsters demonstrate intrinsic tolerance to transplantation-like stimuli, cross-species comparative metabolomic analyses were conducted with hamster, rat, and donor liver samples to seek hepatic cold and IR-adaptive mechanisms. Lower hepatic phosphocholine contents were found in recipients with early graft-dysfunction and with virus-caused cirrhosis or high model for end-stage liver disease scores (≥30). Choline/phosphocholine deficiency in cultured human THLE-2 hepatocytes and animal models weakened hepatocellular cold tolerance and recovery of glutathione and ATP production, which was rescued by phosphocholine supplements. Among the biological processes impacted by choline/phosphocholine deficiency, 3 lipid-related metabolic processes were downregulated, whereas phosphocholine elevated the expression of genes in methylation processes. Consistently, in THLE-2, phosphocholine enhanced the overall RNA m6A methylation, among which the transcript stability of fatty acid desaturase 6 (FADS6) was improved. FADS6 functioned as a key phosphocholine effector in the production of polyunsaturated fatty acids, which may facilitate the hepatocellular recovery of energy and redox homeostasis. Thus, our study reveals the choline-phosphocholine metabolism and its downstream FADS6 functions in hepatic adaptation to cold and IR, which may inspire new strategies to monitor donor liver quality and improve recipient recovery from the liver transplantation process.

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

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

Temporary Portocaval Shunt Provides Superior Intraoperative Hemodynamics and Reduces Blood Loss and Duration of Surgery in Live Donor Liver Transplantation: A Randomized Control Trial

OBJECTIVE

To compare intraoperative hemodynamic parameters, blood loss, renal function, and duration of surgery with and without temporary portocaval shunt (TPCS) in live donor liver transplantation (LT) recipients. Secondary objectives were postoperative early graft dysfunction, morbidity, mortality, total intensive care unit, and hospital stay.

BACKGROUND

Blood loss during recipient hepatectomy for LT remains a major concern. Routine use of TPCS during LT is not yet elucidated.

METHODS

This study is a single-center, open-label, randomized control trial. The sample size was calculated based on intraoperative blood loss. After exclusion, a total of 60 patients, 30 in each arm (TPCS vs no TPCS) were recruited in the trial.

RESULTS

The baseline recipient and donor characteristics were comparable between the groups. The median intraoperative blood loss ( P = 0.004) and blood product transfusions ( P < 0.05) were significantly less in the TPCS group. The TPCS group had significantly improved intraoperative hemodynamics in the anhepatic phase as compared with the no TPCS group ( P < 0.0001), requiring significantly less vasopressor support. This led to significantly better renal function as evidenced by higher intraoperative urine output in the TPCS group ( P = 0.002). Because of technical simplicity, the TPCS group had significantly fewer inferior vena cava injuries (3.3 vs 26.7%, P = 0.026) and substantially shorter hepatectomy time and total duration of surgery (529.4 ± 35.54 vs 606.83 ± 48.13 min, P < 0.0001). The time taken for normalization of lactate in the immediate postoperative period was significantly shorter in the TPCS group (median, 6 vs 13 h; P = 0.04). Although postoperative endotoxemia, major morbidity, 90-day mortality, total intensive care unit, and hospital stay were comparable between both groups, tolerance to enteral feed was earlier in the TPCS group.

CONCLUSIONS

In live donor LT, TPCS is a simple and effective technique that provides superior intraoperative hemodynamics and reduces blood loss and duration of surgery.

Normothermic Liver Machine Perfusion and Successful Transplantation of Split Liver Grafts: From Proof of Concept to Clinical Implementation

BACKGROUND

Normothermic liver machine perfusion (NLMP) is advancing the field of liver transplantation (LT). Beyond improved preservation and organ assessment, NLMP helps to increase organ utilization. We herein address the feasibility and merit of NLMP in split liver transplantation (SLT) to postpone the transplantation of the second split graft to the following day.

METHODS

We analyzed the perfusion characteristics and outcomes of all consecutive adult recipients who underwent SLT following NLMP from February 1, 2018, to June 30, 2023. The primary endpoint was 90-d graft and patient survival. Secondary endpoints were posttransplant complications and 90-d morbidity.

RESULTS

Three right and 3 extended right SLT following NLMP have been performed. NLMP was uneventful in all cases. Perfusion characteristics differed according to graft volume. Mean perfusion time was 17:00 h (±05:13) and bile production ranged between 8 and 21 mL/h. All split grafts fulfilled predefined center viability criteria during NLMP and were transplanted on the following day. The 90-d graft and patient survival rate was 100%. Three patients (50%) required an early relaparotomy, and 2 patients (33.3%) developed biliary complications. The 90-d morbidity as recorded by the comprehensive complication index was 62.7 (±24.7).

CONCLUSIONS

NLMP of split liver grafts is technically feasible and safe. Through prolongation of preservation time, NLMP allows to safely postpone transplantation of the second split liver graft to the next day.

Sequential Normothermic Regional Perfusion and End-ischemic Ex Situ Machine Perfusion Allow the Safe Use of Very Old DCD Donors in Liver Transplantation

BACKGROUND

In Italy, 20 min of continuous, flat-line electrocardiogram are required for death declaration. Despite prolonged warm ischemia time, Italian centers reported good outcomes in controlled donation after circulatory death (cDCD) liver transplantation by combining normothermic regional and end-ischemic machine perfusion (MP). The aim of this study was to evaluate the safety and feasibility of the use of septuagenarian and octogenarian cDCD donors with this approach.

METHODS

All cDCD older than 70 y were evaluated during normothermic regional perfusion and then randomly assigned to dual hypothermic or normothermic MP.

RESULTS

In the period from April 2021 to December 2022, 17 cDCD older than 70 y were considered. In 6 cases (35%), the graft was not considered suitable for liver transplantation, whereas 11 (65%) were evaluated and eventually transplanted. The median donor age was 82 y, being 8 (73%) older than 80. Median functional warm ischemia and no-flow time were 36 and 28 min, respectively. Grafts were randomly assigned to ex situ dual hypothermic oxygenated MP in 6 cases (55%) and normothermic MP in 5 (45%). None was discarded during MP. There were no cases of primary nonfunction, 1 case of postreperfusion syndrome (9%) and 2 cases (18%) of early allograft dysfunction. At a median follow-up of 8 mo, no vascular complications or ischemic cholangiopathy were reported. No major differences were found in terms of postoperative hospitalization or complications based on the type of MP.

CONCLUSIONS

The implementation of sequential normothermic regional and end-ischemic MP allows the safe use of very old donation after circulatory death donors.

Challenges With the Implementation of Machine Perfusion in Clinical Liver Transplantation

Dynamic organ preservation is a relatively old technique which has regained significant interest in the last decade. Machine perfusion (MP) techniques are applied in various fields of solid organ transplantation today. The first clinical series of ex situ MP in liver transplantation was presented in 2010. Since then, the number of research and clinical applications has substantially increased. Despite the notable beneficial effect on organ quality and recipient outcome, MP is still not routinely used in liver transplantation. Based on the enormous need to better preserve organs and the subsequent demand to continuously innovate and develop perfusion equipment further, this technology is also beneficial to test and deliver future therapeutic strategies to livers before implantation. This article summarizes the various challenges observed during the current shift from static to dynamic liver preservation in the clinical setting. The different organ perfusion strategies are discussed first, together with ongoing clinical trials and future study design. The current status of research and the impact of costs and regulations is highlighted next. Factors contributing to costs and other required resources for a worldwide successful implementation and reimbursement are presented third. The impact of research on cost-utility and effectivity to guide the tailored decision-making regarding the optimal perfusion strategy is discussed next. Finally, this article provides potential solutions to the challenging field of innovation in healthcare considering the various social and economic factors and the role of clinical, regulatory, and financial stakeholders worldwide.

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.

The adverse impact of perioperative body composition abnormalities on outcomes after split liver transplantation: a multicenter retrospective cohort study

BACKGROUND

Split liver transplantation (SLT) increases graft availability, but it's safe and effective utilization is insufficiently documented. This study aimed to investigate the association between perioperative body composition abnormalities and outcomes in adult SLT.

MATERIALS AND METHODS

Two hundred forty recipients who underwent SLT in three centers were enrolled in this retrospective cohort study. Body composition abnormalities including sarcopenia, myosteatosis, visceral obesity, and sarcopenic obesity were evaluated at baseline and 1 month after surgery using computed tomography. Their impact on outcomes including early allograft dysfunction, early complications, ICU stay, graft regeneration rate, and survival was analyzed.

RESULTS

Recipients with sarcopenia or myosteatosis had a higher risk of early allograft dysfunction, higher early complication rate, and longer length of ICU stay (all P <0.05), while there was no difference in graft regeneration rate. Recipient and graft survival were significantly worse for recipients with body composition abnormalities (all P <0.05). In multivariable Cox-regression analysis, sarcopenia [hazard ratio (HR)=1.765, P =0.015], myosteatosis (HR=2.066, P =0.002), and visceral obesity (HR=1.863, P =0.008) were independently associated with shorter overall survival. Piling up of the three factors increased the mortality risk stepwise ( P <0.001). Recipients experienced skeletal muscle loss and muscle fat infiltration 1 month after surgery. Postoperative worsening sarcopenia (HR=2.359, P =0.009) and myosteatosis (HR=1.878, P =0.026) were also identified as independent risk factors for mortality.

CONCLUSION

Sarcopenia, myosteatosis, and their progression negatively affect outcomes including early allograft dysfunction, early complications, ICU stay and survival after SLT. Systemic evaluation and dynamic monitoring of body composition are valuable.

Retransplantation in Living Donor Liver Transplantation

The need for retransplantation after living donor liver transplantation can occur early, mainly because of technical difficulties such as hepatic artery thrombosis or as a result of early allograft dysfunction as a symptom of small-for-size syndrome. Patients with autoimmune diseases may develop progressive graft failure from recurrent disease. The ethics of retransplantation can be complicated by the cause of the initial liver disease, which may be self-inflicted or the outcome of malignancy. This is especially true in countries without the availability of deceased donors for salvage, and a second living donor would be needed. Nevertheless, patients who experience early or late graft failure should be considered for retransplant if they are deemed acceptable candidates. When a living donor is required for retransplant, the equipoise between donor risk and autonomy and recipient outcome should be considered.

Liver Transplantation from Elderly Donors (≥85 Years Old)

BACKGROUND

Despite the ongoing trend of increasing donor ages in liver transplantation (LT) setting, a notable gap persists in the availability of comprehensive guidelines for the utilization of organs from elderly donors. This study aimed to evaluate the viability of livers grafts from donors aged ≥85 years and report the post-LT outcomes compared with those from "ideal" donors under 40 years old.

METHODS

Conducted retrospectively at a single center from 2005 to 2023, this study compared outcomes of LTs from donors aged ≥85 y/o and ≤40 y/o, with the propensity score matching to the recipient's gender, age, BMI, MELD score, redo-LT, LT indication, and cause of donor death.

RESULTS

A total of 76 patients received grafts from donors ≥85 y/o and were compared to 349 liver grafts from donors ≤40 y/o. Prior to PSM, the 5-year overall survival was 63% for the elderly group and 77% for the young group (p = 0.002). After PSM, the 5-year overall survival was 63% and 73% (p = 0.1). A nomogram, developed at the time of graft acceptance and including HCC features, predicted 10-year survival after LT using a graft from a donor aged ≥85.

CONCLUSIONS

In the context of organ scarcity, elderly donors emerge as a partial solution. Nonetheless, without proper selection, LT using very elderly donors yields inferior long-term outcomes compared to transplantation from very young donors ≤40 y/o. The resulting nomogram based on pre-transplant criteria allows for the optimization of elderly donor/recipient matching to achieve satisfactory long-term results, in addition to traditional matching methods.

Algorithmic Approach to Deranged Liver Functions After Transplantation

Liver transplant (LT) recipients require close follow-up with regular monitoring of the liver function tests (LFTs). Evaluation of deranged LFT should be individualized depending upon the time since LT, peri-operative events, clinical course, and any complications. These derangements can range from mild and asymptomatic to severe and symptomatic elevations requiring expedited personalized assessment and management. Pattern of LFT derangement (hepatocellular, cholestatic, or mixed), donor-recipient risk factors, timing after LT (post-operative, 1-12 months, and >12 months since LT) along with clinical context and symptomatology are important considerations before proceeding with the initial evaluation. Compliance to immunosuppression and drug interactions should be ascertained along with local epidemiology of infections. Essential initial evaluation must include an ultrasound abdomen with Doppler to rule out any structural causes such as biliary or vascular complications apart from focussed laboratory evaluation. Early allograft dysfunction, ischemia reperfusion injury, small-for-size syndrome, biliary leaks, hepatic artery, and portal vein thrombosis are usual culprits in the early post-operative period whereas viral hepatitis (acute or reactivation), opportunistic infections, and recurrence of the primary disease are more frequent in the later period. Graft rejection, biliary strictures, sepsis, and drug induced liver injury remain possible etiologies at all times points after LT. Initial evaluation algorithm must be customized based on history, clinical examination, risk factors, and pattern and severity of deranged LFT. Allograft rejection is a diagnosis of exclusion and requires liver biopsy to confirm and assess severity. Empirical treatment of rejection sans liver biopsy is discouraged.

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.

Benefits of Hypothermic Oxygenated Perfusion Versus Static Cold Storage in Liver Transplant: A Comprehensive Systematic Review and Meta-analysis

Background

The magnitude of potential benefits that hypothermic oxygenated perfusion (HOPE) may provide for liver transplantation (LT) patients compared to static cold storage (SCS) remains uncertain. In this systematic review and meta-analysis, we aimed to investigate the therapeutic effect that HOPE can offer LT recipients relative to SCS by synthesizing available evidence.

Methods

A literature search was conducted in Embase, Medline, Web of Science, and the Cochrane database up to 1 June, 2023. The included studies were pooled for meta-analysis to synthesize their findings. Subgroup analysis was performed to investigate potential differences between HOPE and SCS for specific subgroups.

Results

A total of 11 studies comprising 1765 patients were included. Compared with SCS, HOPE was associated with a significant reduction in the incidence of early allograft dysfunction (EAD) (OR: 0.36, 95% CI: 0.26-0.50), as well as a noteworthy decrease in graft loss rate within one year (OR: 0.57, 95% CI: 0.33-0.97) and a lower occurrence of Clavien-Dindo grade IIIa or higher complications (OR: 0.62, 95% CI: 0.43-0.89). Subgroup analysis revealed that HOPE significantly reduced the one-year mortality rate, any biliary complications incidence, and acute rejection of transplanted liver rate in patients who received organs from donation after cardiac death (DCD).

Conclusions

HOPE has demonstrated efficacy in reducing the incidence of EAD after LT and shows some potential in diminishing postoperative complications such as biliary complications and acute rejection. This ultimately leads to improved patient prognosis, particularly among those receiving DCD grafts.

Asystolic donor warm ischemia time is associated with development of postreperfusion syndrome in donation after circulatory death liver transplant

BACKGROUND

Individual events during donation after circulatory death (DCD) procurement, such as hypotensive or hypoxic warm ischemia, or circulatory arrest are all a part of donor warm ischemia time (dWIT), and may have differing effects on the outcome of the liver graft. This study aimed to identify risk factors for postreperfusion syndrome (PRS), a state of severe hemodynamic derangement following graft reperfusion, and its impact on DCD liver transplantation (LT) outcomes.

METHODS

This was a retrospective analysis using 106 DCD LT. Detailed information for events during procurement (withdrawal of life support; systolic blood pressure < 80 mmHg; oxygen saturation < 80%; circulatory arrest; aortic cold perfusion) and their association with the development of PRS were examined using logistic regression.

RESULTS

The overall incidence of PRS was 26.4%, occurring in 28 patients. Independent risk factors for PRS were asystolic dWIT (odds ratio (OR) 3.65, 95% confidence interval (CI) 1.38-9.66) and MELD score (OR 1.06, 95% CI 1.01-1.10). Total bilirubin was significantly higher in the PRS group at postoperative day (POD) 1 (p = .02; 5.2 mg/dL vs. 3.4 mg/dL), POD 3 (p = .049; 4.5 mg/dL vs. 2.8 mg/dL), and POD 7 (p = .04; 3.1 mg/dL vs. 1.9 mg/dL). Renal replacement therapy after LT was more likely to be required in the PRS group (p = .01; 48.2% vs. 23.1%).

CONCLUSION

Asystolic dWIT is a risk factor for the development of PRS in DCD LT. Our results suggest that asystolic dWIT should be considered when selecting DCD liver donors.

Outcomes of living donor liver transplant recipients receiving grafts with the graft-to-recipient weight ratio less than 0.6%: A matched pair analysis

We sometimes experience living donor liver transplantation (LDLT) involving very small grafts with graft-to-recipient weight ratio (GRWR) < 0.6% when the actual graft size is smaller than predicted. The outcomes in this situation have not been fully investigated. The present study aimed to determine the graft outcomes of LDLT with GRWR < 0.6%. We retrospectively reviewed 280 cases of adult LDLT performed at our institution between January 2000 and March 2021. In our institution, the lower limit for graft volume/standard liver volume ratio was 30%. The patients were divided into 2 groups according to the cutoff value of 0.6% for actual GRWR. Graft survival and surgical outcomes, including small-for-size syndrome (SFSS), were compared between the groups using propensity score matching analysis. Risk factors associated with SFSS in recipients with GRWR < 0.6% were also evaluated. Fifty-nine patients received grafts with GRWR < 0.6%. After propensity score matching, similar graft survival rates were observed for GRWR < 0.6% (n = 53) and GRWR ≥ 0.6% (n = 53) ( p = 0.98). However, patients with GRWR < 0.6% had a significantly worse 3-month graft survival rate (86.8% vs. 98.1%, p = 0.03) and higher incidence of SFSS ( p < 0.001) than patients with GRWR ≥0.6%. On multivariate analysis, Model for End-Stage Liver Disease score and donor age were associated with SFSS in patients with GRWR < 0.6%. The same factors were also associated with graft survival. In conclusion, although similar overall graft survival rates were observed for LDLT with GRWR < 0.6% and GRWR ≥ 0.6%, GRWR < 0.6% was associated with an increased risk of SFSS. Appropriate donor and recipient selection is important for successful LDLT with very small grafts.

Characterization of Perioperative Serotonin in Patients Undergoing Orthotopic Liver Transplantation

Background: Platelets were shown to be relevant for liver regeneration. In particular, platelet-stored serotonin (5-HT) proved to be a pro-regenerative factor in this process. The present study aimed to investigate the perioperative course of 5-HT and evaluate associations with patient and graft outcomes after othotopic liver transplantation (OLT). Methods: 5-HT was quantified in plasma and serum of 44 OLT recipients perioperatively, and in their respective donors. Olthoff's criteria for early allograft dysfunction (EAD) were used to evaluate postoperative outcomes. Results: Patients with higher donor intra-platelet 5-HT per platelet (IP 5-HT PP) values had significantly lower postoperative transaminases (ASAT POD1: p = 0.006, ASAT POD5: p = 0.006, ASAT POD10: p = 0.02, ALAT POD1: p = 0.034, ALAT POD5: p = 0.017, ALAT POD10: p = 0.04). No significant differences were seen between postoperative 5-HT values and the occurrence of EAD. A tendency was measured that donor IP 5-HT PP is lower in donor-recipient pairs that developed EAD (p = 0.07). Conclusions: Donor IP 5-HT PP might be linked to the postoperative development of EAD after OLT, as higher donor levels are correlated with a more favorable postoperative course of transaminases. Further studies with larger cohorts are needed to validate these findings.

Differential Effects of HDAC6 Inhibition Versus Knockout During Hepatic Ischemia-reperfusion Injury Highlight Importance of HDAC6 C-terminal Zinc-finger Ubiquitin-binding Domain

BACKGROUND

Ischemia-reperfusion injury (IRI) causes significant morbidity in liver transplantation among other medical conditions. IRI following liver transplantation contributes to poor outcomes and early graft loss. Histone/protein deacetylases (HDACs) regulate diverse cellular processes, play a role in mediating tissue responses to IRI, and may represent a novel therapeutic target in preventing IRI in liver transplantation.

METHODS

Using a previously described standardized model of murine liver warm IRI, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were assessed at 24 and 48 h after reperfusion to determine the effect of different HDAC inhibitors.

RESULTS

Broad HDAC inhibition with trichostatin-A (TSA) was protective against hepatocellular damage (P < 0.01 for AST and P < 0.05 for ALT). Although HDAC class I inhibition with MS-275 provided statistically insignificant benefit, tubastatin-A (TubA), an HDAC6 inhibitor with additional activity against HDAC10, provided significant protection against liver IRI (P < 0.01 for AST and P < 0.001 for ALT). Surprisingly genetic deletion of HDAC6 or -10 did not replicate the protective effects of HDAC6 inhibition with TubA, whereas treatment with an HDAC6 BUZ-domain inhibitor, LakZnFD, eliminated the protective effect of TubA treatment in liver ischemia (P < 0.01 for AST and P < 0.01 for ALT).

CONCLUSIONS

Our findings suggest TubA, a class IIb HDAC inhibitor, can mitigate hepatic IRI in a manner distinct from previously described class I HDAC inhibition and requires the HDAC6 BUZ-domain activity. Our data corroborate previous findings that HDAC targets for therapeutic intervention of IRI may be tissue-specific, and identify HDAC6 inhibition as a possible target in the treatment of liver IRI.

Short-term postoperative bacteriobilia or fungibilia in liver transplantation patients with donation after circulatory death allografts associated with a longer hospital stay: A single-center retrospective observational study in China

BACKGROUND

Normal bile is sterile. Studies have shown that cholangitis after liver transplantation (LT) was associated with a relatively poor prognosis. It remains unclear whether the bacteriobilia or fungibilia impact the patient outcomes in LT recipients, especially with donation after circulatory death (DCD) allografts, which was correlated with a higher risk of allograft failure.

METHODS

This retrospective study included 139 LT recipients of DCD grafts from 2019 to 2021. All patients were divided into two groups according to the presence or absence of bacteriobilia or fungibilia. The prevalence and microbial spectrum of postoperative bacteriobilia or fungibilia and its possible association with outcomes, especially hospital stay were analyzed.

RESULTS

Totally 135 and 171 organisms were isolated at weeks 1 and 2, respectively. Among all patients included in this analysis, 83 (59.7%) developed bacteriobilia or fungibilia within 2 weeks post-transplantation. The occurrence of bacteriobilia or fungibilia (β = 7.43, 95% CI: 0.02 to 14.82, P = 0.049), particularly the detection of Pseudomonas (β = 18.84, 95% CI: 6.51 to 31.07, P = 0.003) within 2 weeks post-transplantation was associated with a longer hospital stay. However, it did not affect the graft and patient survival.

CONCLUSIONS

The occurrence of bacteriobilia or fungibilia, particularly Pseudomonas within 2 weeks post-transplantation, could influence the recovery of liver function and was associated with prolonged hospital stay but not the graft and patient survival.

Sarcopenic obesity may predict worse liver regeneration after right graft living donor liver transplantation

Sarcopenic obesity impairs the outcome after liver transplantation. The effect of this on liver regeneration has not yet been studied. The aim of this study was to evaluate the potential effect of body composition changes on liver volume gain after living donor liver transplantation. We observed liver regeneration in 100 patients who underwent living donor liver transplantation using right lobe grafts (Segments V-VIII). Liver volumetry and body composition analysis were performed based on CT images with special software. The gain of liver volume was calculated between 2 points in time considering the absolute and percentage values: before surgery and early after surgery, with a median time of 10 days. Pearson's correlation and multivariate analysis using stepwise multiple regression were used to examine the potential correlation between body composition and liver volume gain. The liver volume increase was significantly negatively correlated with adipose tissue in the body stem ( r = -0.4, p < 0.001) and positively correlated with psoas mass ( r = 0.24, p = 0.02). These results correspond with those of the multiple regression analysis, which indicated adipose tissue (ß = -1.0, p < 0.001) and psoas mass (ß = 0.12, p < 0.001). The presence of malignancy as an indication for liver transplantation was another significant independent factor negatively affecting liver growth (ß = -13.1, p = 0.046). Sarcopenic obesity predicts an impaired liver volume increase after living donation. This could worsen the postoperative outcome. The role of alimentary interventions and exercises in improving body composition and thus postoperative outcome should be evaluated through prospective interventional studies.

Intraoperative Normal Saline Administration and Acute Kidney Injury in Patients Undergoing Liver Transplantation

BACKGROUND

Normal saline is still used in patients undergoing living donor liver transplantation (LDLT) with normonatremia. We investigated whether the normal saline administered during LDLT is associated with the increased risk of acute kidney injury (AKI) compared with the balanced crystalloids.

METHODS

We reviewed 1011 cases undergoing LDLT. The primary exposure variable was normal saline administered intraoperatively compared with the balanced crystalloid. To compare the risk of AKI after adjusting for potential confounders of baseline characteristics and surgical parameters, a propensity score matching analysis was performed. As a sensitivity analysis, ordinal logistic regression analysis was performed for AKI using inverse probability of treatment weighting (IPTW).

RESULTS

The incidence of AKI was significantly higher in the saline group (n = 88/174, 50.6%) than in the balanced group (n = 67/174, 38.5%) after matching (P = .010). The incidence of stage 2 or 3 AKI was also significantly higher in the saline group (n = 26/174, 14.9%) than in the balanced group (n = 43/174, 24.7%) after matching (P = .022). The length of hospital stay was significantly longer in the saline group than in the balanced group after matching. Ordinal logistic regression analysis using IPTW showed that the saline group showed a significant association of saline administration with the risk of AKI (odds ratio 1.23, 95% CI 1.05-1.28, P = .013).

CONCLUSION

Our propensity score analysis using propensity score matching and IPTW showed that normal saline administration during LDLT is associated with a high risk of postoperative AKI and longer hospital stays. However, our results should be interpreted carefully due to the relatively long period of data collection.

Incidence, Outcomes, and Risk Factors of Intraoperative Cardiac Arrest During Orthotopic Liver Transplantation

BACKGROUND

Intraoperative cardiac arrest (ICA) during liver transplantation (LT) is a rare surgical complication that results in devastating outcomes. Moreover, previous worldwide studies have found inconsistencies in the risk factors associated with ICA in LT.

METHODS

This was a retrospective cohort study of adult patients who underwent LT between January and October 2021 at Siriraj Hospital, a tertiary care hospital. The incidence of ICA and outcomes of patients who experienced ICA were examined. Risk factors associated with ICA were investigated as a secondary objective.

RESULTS

Among 342 patients, the incidence of ICA was 3.5% (95% CI 1.8%-6.1%). Of these, 33.3% died intraoperatively. Among patients with ICA, 41.7% died within 30 days, compared with only 7.6% in those without ICA (P = .002). Moreover, the in-hospital mortality rate of those with ICA was 58.3%, which was significantly higher than that of those without ICA (9.7%, P < .001). However, 41.7% of patients with ICA were discharged alive with long-term survival. Because ICA is a rare event, we found only 2 independent factors significantly associated with ICA. These factors include intraoperative temperature below 35°C, with an odds ratio (OR) of 6.07 (95% CI:1.32-27.88, P = .02) and elevated intraoperative serum potassium, with an OR of 4.57 (95% CI:2.15-9.67, P < .001).

CONCLUSIONS

ICA is associated with high perioperative and in-hospital mortality. However, our findings suggest that with effective management of ICA, more than 40% of these patients could be discharged with excellent long-term outcomes. Hypothermia and hyperkalemia were independent risk factors significantly associated with ICA.

The learning curve of liver procurement from donation after circulatory death donor

PURPOSE

This study aimed to evaluate the learning curve for donation after circulatory death (DCD) liver procurement.

METHODS

DCD liver procurements performed by a single surgeon (n = 36) were separated into two phases: the learning and established phases.

RESULTS

A cumulative sum analysis using the operative donor warm ischemia time (oWIT) and donor hepatectomy time (dHT) showed that ten and seven cases, respectively, were needed for stable surgical procedures. The established phase (n = 26, since Case 11) was likely to have a shorter oWIT (p = 0.06; 7.5 min vs. 9 min) and dHT (p = 0.09; 32 min vs. 37 min) than the learning phase. While the hospital stay was significantly shorter and donor age was older in the established phase (p = 0.04 and p < 0.01; 12 days vs. 41 days and 38 years vs. 24 years, respectively), the incidence rates of post-transplant complications such as early allograft dysfunction (p = 0.74) and vascular complications (p = 0.53) were similar.

CONCLUSIONS

The learning curve for DCD liver procurement demonstrated that 10 cases were required to establish these techniques. The oWIT and dHT for DCD liver procurement can represent markers of operative efficiency.

Graft-derived cfDNA Monitoring in Plasma and Bile During Normothermic Machine Perfusion in Liver Transplantation Is Feasible and a Potential Tool for Assessing Graft Viability

BACKGROUND

Ex vivo normothermic machine perfusion (NMP) is an organ preservation technique that enables an extended assessment of graft suitability before liver transplantation (LT). Established monitoring protocols used during NMP vary significantly in their assessment of transplant suitability when applied to the same grafts. Graft-derived cell-free DNA (gdcfDNA) analysis is an emerging tool for monitoring graft health post-transplantation. We investigated the feasibility of monitoring gdcfDNA during NMP for LT in a proof-of-concept, observational study.

METHODS

Serial plasma and bile samples were collected during NMP for 10 consecutive grafts, at 15 min post-machine reperfusion and then 2-h intervals. Digital polymerase chain reaction was used to quantify gdcfDNA at each time point.

RESULTS

Five grafts were suitable for LT, there were no cases of primary nonfunction or death in the recipients. gdcfDNA was quantified in all bile and plasma samples (n > 100). In plasma, gdcfDNA concentrations climbed post-machine reperfusion until 4.25 h (median 2.25 h = 15.98 × 10 6 copies/mL, 4.25 h = 40.21 × 10 6 copies/mL). gdcfDNA levels then diverged significantly when comparing the viable and non-viable graft groups (6.25 h, median viable: 117.15 × 10 6 copies/mL versus non-viable: 16.72 × 10 6 copies/mL, P  = 0.01). These opposing trends correlated in each graft and in all cases with the viable/non-viable outcome. There was a trend of gradual decline in bile gdcfDNA from viable grafts post-machine reperfusion; discarded grafts showed more variable patterns of release.

CONCLUSIONS

gdcfDNA analysis during NMP is a feasible and potential tool to inform viability assessment during NMP for LT. Bile gdcfDNA monitoring offers the prospect of an objective means to assess the degree of biliary injury associated with organ procurement.

Dynamic immune cell profiling identified natural killer cell shift as the key event in early allograft dysfunction after liver transplantation

Early allograft dysfunction (EAD) is a life-threatening and fast-developing complication after liver transplantation. The underlying mechanism needs to be better understood, and there has yet to be an efficient therapeutic target. This study retrospectively reviewed 109 patients undergoing liver transplantation, with dynamic profiling of CD3/4/8/16/19/45/56 on the peripheral immune cells (before transplant and 2-4 days after). Altogether, 35 out of the 109 patients developed EAD after liver transplantation. We observed a significant decrease in the natural killer cell proportion (NK cell shift, p = 0.008). The NK cell shift was linearly correlated with cold ischemic time (p = 0.016) and was potentially related to the recipients' outcomes. In mouse models, ischemic/reperfusion (I/R) treatments induced the recruitment of NK cells from peripheral blood into liver tissues. NK cell depletion blocked a series of immune cascades (including CD8+ CD127+ T cells) and inhibited hepatocyte injury effectively in I/R and liver transplantation models. We further found that I/R treatment increased hepatic expression of the ligands for natural killer group 2 member D (NKG2D), a primary activating cell surface receptor in NK cells. Blockade of NKG2D showed a similar protective effect against I/R injury, indicating its role in NK cell activation and the subsequent immunological injury. Our findings built a bridge for the translation from innate immune response to EAD at the bedside. Peripheral NK cell shift is associated with the incidence of EAD after liver transplantation. NKG2D-mediated NK cell activation is a potential therapeutic target.

OXIDATIVE study: A pilot prospective observational cohort study protocol examining the influence of peri-reperfusion hyperoxemia and immune dysregulation on early allograft dysfunction after orthotopic liver transplantation

Early allograft dysfunction (EAD) is a functional hepatic insufficiency within a week of orthotopic liver transplantation (OLT) and is associated with morbidity and mortality. The etiology of EAD is multifactorial and largely driven by ischemia reperfusion injury (IRI), a phenomenon characterized by oxygen scarcity followed by paradoxical oxidative stress and inflammation. With the expanded use of marginal allografts more susceptible to IRI, the incidence of EAD may be increasing. This necessitates an in-depth understanding of the innate molecular mechanisms underlying EAD and interventions to mitigate its impact. Our central hypothesis is peri-reperfusion hyperoxemia and immune dysregulation exacerbate IRI and increase the risk of EAD. We will perform a pilot prospective single-center observational cohort study of 40 patients. The aims are to determine (1) the association between peri-reperfusion hyperoxemia and EAD and (2) whether peri-reperfusion perturbed cytokine, protein, and hypoxia inducible factor-1 alpha (HIF-1α) levels correlate with EAD after OLT. Inclusion criteria include age ≥ 18 years, liver failure, and donation after brain or circulatory death. Exclusion criteria include living donor donation, repeat OLT within a week of transplantation, multiple organ transplantation, and pregnancy. Partial pressure of arterial oxygen (PaO2) as the study measure allows for the examination of oxygen exposure within the confines of existing variability in anesthesiologist-administered fraction of inspired oxygen (FiO2) and the inclusion of patients with intrapulmonary shunting. The Olthoff et al. definition of EAD is the primary outcome. Secondary outcomes include postoperative acute kidney injury, pulmonary and biliary complications, surgical wound dehiscence and infection, and mortality. The goal of this study protocol is to identify EAD contributors that could be targeted to attenuate its impact and improve OLT outcomes. If validated, peri-reperfusion hyperoxemia and immune perturbations could be targeted via FiO2 titration to a goal PaO2 and/or administration of an immunomodulatory agent by the anesthesiologist intraoperatively.

Everolimus Mitigates the Risk of Hepatocellular Carcinoma Recurrence after Liver Transplantation

To obtain long-term data on the use of everolimus in patients who underwent liver transplantation for hepatocellular carcinoma, we conducted a retrospective, single-center analysis of adult recipients transplanted between 2013 and 2021. Patients on everolimus-incorporating immunosuppression were matched with those on tacrolimus using an inverse probability of treatment weighting methodology. Two propensity-matched groups of patients were thus compared: 233 (45.6%) receiving everolimus versus 278 (54.4%) on tacrolimus. At a median (interquartile range) follow-up of 4.4 (3.8) years after transplantation, everolimus patients showed a reduced risk of recurrence versus tacrolimus (7.7% versus 16.9%; RR = 0.45; p = 0.002). At multivariable analysis, microvascular infiltration (HR = 1.22; p < 0.04) and a higher tumor grading (HR = 1.27; p < 0.04) were associated with higher recurrence rate while being within Milan criteria at transplant (HR = 0.56; p < 0.001), a successful pre-transplant downstaging (HR = 0.63; p = 0.01) and use of everolimus (HR = 0.46; p < 0.001) had a positive impact on the risk of post-transplant recurrence. EVR patients with earlier drug introduction (≤30 days; p < 0.001), longer treatment duration (p < 0.001), and higher drug exposure (≥5.9 ng/mL; p < 0.001) showed lower recurrence rates versus TAC. Based on our experience, everolimus provides a reduction in the relative risk of hepatocellular carcinoma recurrence, especially for advanced-stage patients and those with earlier drug administration, higher drug exposure, and longer time on treatment. These data advocate for early everolimus introduction after liver transplantation to reduce the attrition rate consequent to chronic immunosuppression.

High intra-patient variability of tacrolimus within post-operative 1 month predicted worse 1-year outcomes in pediatric liver transplant recipients

BACKGROUND

The pharmacokinetics of tacrolimus (TAC) show high intra-patient variability (IPV), which is associated with poor long-term outcomes following adult liver transplantation (LT). However, this relationship remains to be confirmed in pediatric liver transplant (PLT) recipients. The present study aimed to investigate the association between TAC IPV and grafts or patient outcomes after pediatric liver transplantion.

METHODS

This retrospective study included 848 PLT recipients (including infants) between January, 2016, and June, 2021. The IPV of TAC concentrations was estimated by calculating the coefficient of variation (CV) of trough concentrations in whole blood within 1 month after transplantation. Patients were categorized into two groups, low IPV (CV < 45%) and high IPV (CV ≥ 45%), based on the third quartile of the CV distribution.

RESULTS

A total of 848 patients were included in our study. The low CV group included 614 patients, with a mean TAC trough concentration of 8.59 ± 1.65 ng/ml and a median CV of 32.37%. In contrast, the high CV group included 214 patients, the mean TAC trough concentration and median CV were 8.81 ± 2.00 ng/ml and 54.88%, respectively. The median hospital duration was significantly higher in the high CV group (22 days vs. 20 days, P = 0.01). Univariate analysis was performed to evaluate the significant differences in 1-year recipient survival (P = 0.041) and 1-year graft survival (P = 0.005) between the high- and low-CV groups. Moreover, high CV (HR 2.316, 95%CI 1.026-5.231, P = 0.043) and persistent EBV viremia (HR 13.165, 95%CI 3.090-56.081, P < 0.001) were identified as independent risk factors for 1- year mortality after PLT.

CONCLUSIONS

PLT recipients with high TAC trough concentration of CV in the first month were associated with poor 1-year outcomes. This CV calculation provides a valuable strategy to monitor TAC exposure.

Association of donor hepatectomy time with liver transplantation outcomes: A multicenter retrospective study

BACKGROUND

Prolonged donor hepatectomy time may be implicated in early and late complications of liver transplantation.

AIM

To evaluate the impact of donor hepatectomy time on outcomes of liver transplant recipients, mainly early allograft dysfunction.

METHODS

This multicenter retrospective study included brain-dead donors and adult liver graft recipients. Donor-recipient matching was obtained through a crossover list. Clinical and laboratory data were recorded for both donors and recipients. Donor hepatectomy, cold ischemia, and warm ischemia times were recorded. Primary outcome was early allograft dysfunction. Secondary outcomes included need for retransplantation, length of intensive care unit and hospital stay, and patient and graft survival at 12 months.

RESULTS

From January 2019 to December 2021, a total of 243 patients underwent a liver transplant from a brain-dead donor. Of these, 57 (25%) developed early allograft dysfunction. The median donor hepatectomy time was 29 (23-40) min. Patients with early allograft dysfunction had a median hepatectomy time of 25 (22-38) min, whereas those without it had a median time of 30 (24-40) min (P = 0.126).

CONCLUSION

Donor hepatectomy time was not associated with early allograft dysfunction, graft survival, or patient survival following liver transplantation.

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.

Size Matching Deceased Donor Livers: The Tampa General Measurement System

BACKGROUND

No reliable or standardized system exists for measuring the size of deceased donor livers to determine whether they will fit appropriately into intended recipients.

METHODS

This retrospective, single-center study evaluated the efficacy of Tampa General Hospital's size-matching protocol for consecutive, deceased donor liver transplantations between October 2021 and November 2022. Our protocol uses cross-sectional imaging at the time of organ offer to compare the donor's right hepatic lobe size with the recipient's right hepatic fossa. Outcomes were analyzed, including large-for-size syndrome, small-for-size syndrome, early allograft dysfunction, primary nonfunction, graft survival, and patient survival.

RESULTS

We included 171 patients in the study. The donor liver physically fit in all the patients except one whose pretransplant imaging was outdated. One patient (0.6%) had large-for-size syndrome, none had small-for-size syndrome, 15 (10%) had early allograft dysfunction, and none had primary nonfunction. There were 11 (7%) patient deaths and 11 (7%) graft failures.

CONCLUSION

Our measurement system is fast and effective. It reliably predicts whether the donor liver will fit in the intended recipient and is associated with low rates of early allograft dysfunction.

Obstacles to implement machine perfusion technology in routine clinical practice of transplantation: Why are we not there yet?

Machine perfusion of solid human organs is an old technique, and the basic principles were presented as early as 1855 by Claude Barnard. More than 50 years ago, the first perfusion system was used in clinical kidney transplantation. Despite the well-known benefits of dynamic organ preservation and significant medical and technical development in the last decades, perfusion devices are still not in routine use. This article describes the various challenges to implement this technology in practice, critically analyzing the role of all involved stakeholders, including clinicians, hospitals, regulatory, and industry, on the background of regional differences worldwide. The clinical need for this technology is discussed first, followed by the current status of research and the impact of costs and regulations. Considering the need for strong collaborations between clinical users, regulatory bodies, and industry, integrated road maps and pathways required to achieve a wider implementation are presented. The role of research development, clear regulatory pathways, and the need for more flexible reimbursement schemes is discussed together with potential solutions to address the most relevant hurdles. This article paints an overall picture of the current liver perfusion landscape and highlights the role of clinical, regulatory, and financial stakeholders worldwide.

From large-for-size to large-for-flow: A paradigm shift in liver transplantation

Liver graft-recipient matching remains challenging, and both morphologic and hemodynamic characteristics have been shown to be relevant indicators of post-transplant outcomes. However, no combined analysis is available to date. To study the impact of both morphologic and hemodynamic characteristics of liver grafts on transplantation outcomes, we retrospectively evaluated all consecutive 257 liver transplantations with prospective hemodynamic measurements from 2017 to 2020 in a single-center perspective. First, a morphologic analysis compared recipients with or without large-for-size (LFS), defined by a graft/recipient weight ratio >2.5% and excluding extreme LFS. Second, a hemodynamic analysis compared recipients with or without low portal flow (LPF; <80 mL/min per 100 g of liver tissue). Third, an outcome analysis combining LPF and LFS was performed, focusing on liver graft-related morbidity (LGRM), graft and patient survival. LGRM was a composite endpoint, including primary nonfunction, high-risk L-Graft7 category, and portal vein thrombosis. Morphologic analysis showed that LFS (n=33; 12.9%) was not associated with an increased LGRM (12.1% vs 9.4%; p =0.61) or impaired graft and patient survival. However, the hemodynamic analysis showed that LPF (n=43; 16.8%) was associated with a higher LGRM (20.9% vs 7.5%, p = 0.007) and a significantly impaired 90-day graft and patient survival. Multivariable analysis identified LPF but not LFS as an independent risk factor for LGRM (OR: 2.8%; CI:1.088-7.413; and p = 0.03), 90-day (HR: 4%; CI: 1.411-11.551; and p = 0 .01), and 1-year patient survival. LPF is a significant predictor of post-liver transplantation morbi-mortality, independent of LFS when defined as a morphologic metric alone. Consequently, we propose the novel concept of large-for-flow, which may guide graft selection and improve perioperative management of LPF.

Current Techniques and Indications for Machine Perfusion and Regional Perfusion in Deceased Donor Liver Transplantation

Since the advent of University of Wisconsin preservation solution in the 1980s, clinicians have learned to work within its confines. While affording improved outcomes, considerable limitations still exist and contribute to the large number of livers that go unused each year, often for fear they may never work. The last 10 years have seen the widespread availability of new perfusion modalities which provide an opportunity for assessing organ viability and prolonged organ storage. This review will discuss the role of in situ normothermic regional perfusion for livers donated after circulatory death. It will also describe the different modalities of ex situ perfusion, both normothermic and hypothermic, and discuss how they are thought to work and the opportunities afforded by them.

Left Gastric Vein Direct Anastomosis as Alternative to Portal Flow Reconstruction in Liver Transplantation

Introduction

The most relevant limiting factor for performing end-to-end anastomosis is portal vein thrombosis (PVT), which leads to challenging vascular reconstructions. This study aimed to analyze a single center's experience using the left gastric vein (LGV) for portal flow reconstruction in liver transplantation (LT).

Methods

This retrospective observational study reviewed laboratory and imaging tests, a description of the surgical technique, and outpatient follow-up of patients with portal system thrombosis undergoing LT with portal flow reconstruction using the LGV. This study was conducted at a single transplant reference center in the northeast region of Brazil from January 2016 to December 2021.

Results

Between January 2016 and December 2021, 848 transplants were performed at our center. Eighty-two patients (9.7%) presented with PVT, most of whom were treated with thrombectomy. Nine patients (1.1% with PVT) had extensive thrombosis of the portal system (Yerdel III or IV), which required end-to-side anastomosis between the portal vein and the LGV without graft, and had no intraoperative complications. All patients had successful portal flow in Doppler ultrasound control evaluations.

Discussion

The goal was to reestablish physiological flow to the graft. A surgical strategy includes using the LGV graft. According to our reports, using LGV fulfilled the requirements for excellent vascular anastomosis and even allowed the dispensing of venous grafts. This is the largest case series in a single center of reconstruction of portal flow with direct anastomosis with the LGV without needing a vascular graft.

Sevoflurane preconditioning in living liver donation is associated with better initial graft function after pediatric transplantation: a retrospective study

INTRODUCTION

Initial allograft function determines the patient's immediate prognosis in pediatric liver transplantation. Ischemia-reperfusion injuries play a role in initial poor graft function (IPGF). In animal studies, preconditioning with inhaled anesthetic agents has demonstrated a protective effect on the liver. In humans, the few available studies are conflicting. This study assesses the association between the hypnotic agent used to maintain anesthesia during hepatectomy in living donors and the occurrence of IPGF after pediatric transplantation.

METHODS

We conducted a single-center retrospective analysis of children who received a living donor liver transplant (LDLT) between 2010 and 2019. We analyzed the incidence of EAD according to the hypnotic agent used to maintain general anesthesia during donor hepatectomy.

RESULTS

We included 183 pairs of patients (living donors-recipients). The anesthetics used in the donor were propofol (n = 85), sevoflurane (n = 69), or propofol with sevoflurane started 30 min before clamping (n = 29). Forty-two children (23%) developed IPGF. After multivariate logistic regression analysis, factors significantly associated with the occurrence of IPGF were the anesthesia maintenance agent used in the donor (p = 0.004), age of the donor (p = 0.03), duration of transplant surgery (p = 0.009), preoperative receiver neutrophil to lymphocyte ratio (p = 0.02), and albumin (p = 0.05).

CONCLUSION

Significantly fewer children who received a graft from a donor in whom only sevoflurane was used to maintain anesthesia developed IPGF. Although additional research is needed, this preconditioning strategy may provide an option to prevent IPGF after living liver donation.

The Predictive Value of Graft Viability and Bioenergetics Testing Towards the Outcome in Liver Transplantation

Donor organ biomarkers with sufficient predictive value in liver transplantation (LT) are lacking. We herein evaluate liver viability and mitochondrial bioenergetics for their predictive capacity towards the outcome in LT. We enrolled 43 consecutive patients undergoing LT. Liver biopsy samples taken upon arrival after static cold storage were assessed by histology, real-time confocal imaging analysis (RTCA), and high-resolution respirometry (HRR) for mitochondrial respiration of tissue homogenates. Early allograft dysfunction (EAD) served as primary endpoint. HRR data were analysed with a focus on the efficacy of ATP production or P-L control efficiency, calculated as 1-L/P from the capacity of oxidative phosphorylation P and non-phosphorylating respiration L. Twenty-two recipients experienced EAD. Pre-transplant histology was not predictive of EAD. The mean RTCA score was significantly lower in the EAD cohort (-0.75 ± 2.27) compared to the IF cohort (0.70 ± 2.08; p = 0.01), indicating decreased cell viability. P-L control efficiency was predictive of EAD (0.76 ± 0.06 in IF vs. 0.70 ± 0.08 in EAD-livers; p = 0.02) and correlated with the RTCA score. Both RTCA and P-L control efficiency in biopsy samples taken during cold storage have predictive capacity towards the outcome in LT. Therefore, RTCA and HRR should be considered for risk stratification, viability assessment, and bioenergetic testing in liver transplantation.

Aging with a Liver Graft: Analysis of Very Long-Term Survivors after Liver Transplantation

BACKGROUND

In Italy, data on long-term survivors after liver transplantation are lacking.

MATERIALS AND METHODS

We conducted a hybrid design study on a cohort of 359 adult recipients who received transplants between 1996 and 2002 to identify predictors of survival and the prevalence of co-morbidities among long-term survivors.

RESULTS

The actuarial (95% CI) patient survival was 96% (94.6-98.3%), 69% (64.2-73.6%), 55% (49.8-59.9%), 42.8% (37.6-47.8%), and 34% (29.2-38.9%) at 1, 5, 10, 15, and 20 years, respectively. The leading causes of death were hepatitis C virus recurrence (24.6%), extrahepatic malignancies (16.9%), infection (14.4%), and hepatocellular carcinoma recurrence (14.4%). The factors associated with the survival probability were younger donor and recipient ages (p = 0.001 and 0.004, respectively), female recipient sex (p < 0.001), absence of HCV (p < 0.01), absence of HCC (p = 0.001), and absence of diabetes mellitus at one year (p < 0.01). At the latest follow-up, the leading comorbidities were hypertension (53.6%), obesity (18.7%), diabetes mellitus (17.1%), hyperlipidemia (14.7%), chronic kidney dysfunction (14.7%), and extrahepatic malignancies (13.8%), with 73.9% of patients having more than one complication.

CONCLUSIONS

Aging with a liver graft is associated with an increased risk of complications and requires ongoing care to reduce the long-term attrition rate resulting from chronic immunosuppression.

Optimized results of the liver partition program for split-liver transplantation

INTRODUCTION

Split liver transplantation is a procedure performed throughout Europe. In 2018 in Catalonia, the distribution of donors was redefined, being potential candidates for SPLIT all those under 35-years and it was made flexible the adult selection for the right graft. The study aim is to evaluate the effect of this modifications on the use of Split donors on the adult/pediatric waiting lists, as well as to evaluate the post-transplant results of adults who received a Split donor.

METHODS

Observational and retrospective study; 2 data collection periods "PRE" (2013-2017) and "POST" (2018-2021). The adults recipients results were analyzed by a propensity score matching.

RESULTS

In the first period 3 donors were registered and 3 pediatric patients and 2 adults recieved a transplant. In the POST period, 24 donations with liver bipartition were made, performing the transplant in 19 adults and 24 childrens. When comparing the adults waiting lists, a significant decrease was evidenced, both for adults (p = 0,0001) and on the children's waiting list (p = 0,0004), and up to 3 times there were no recipients on the pediatric waiting list. No significant differences between hospital morbidity or mortality or overall survival were observed in the group of adult recipients of Split grafts.

CONCLUSIONS

The flexibility in the selection of the adult recipient and the new distribution of donors makes possible to increase the bipartition rate, reducing the pediatric waiting list without worsening the adults results transplant recipients or their permanence on the waiting list.

Prolonged hypothermic machine perfusion enables daytime liver transplantation - an IDEAL stage 2 prospective clinical trial

Background

Liver transplantation is traditionally performed around the clock to minimize organ ischemic time. However, the prospect of prolonging preservation times holds the potential to streamline logistics and transform liver transplantation into a semi-elective procedure, reducing the need for nighttime surgeries. Dual hypothermic oxygenated machine perfusion (DHOPE) of donor livers for 1-2 h mitigates ischemia-reperfusion injury and improves transplant outcomes. Preclinical studies have shown that DHOPE can safely extend the preservation of donor livers for up to 24 h.

Methods

We conducted an IDEAL stage 2 prospective clinical trial comparing prolonged (≥4 h) DHOPE to conventional (1-2 h) DHOPE for brain-dead donor livers, enabling transplantation the following morning. Liver allocation to each group was based on donor hepatectomy end times. The primary safety endpoint was a composite of all serious adverse events (SAE) within 30 days after transplantation. The primary feasibility endpoint was defined as the number of patients assigned and successfully receiving a prolonged DHOPE-perfused liver graft. Trial registration at: WHO International Clinical Trial Registry Platform, number NL8740.

Findings

Between November 1, 2020 and July 16, 2022, 24 patients were enrolled. The median preservation time was 14.5 h (interquartile range [IQR], 13.9-15.5) for the prolonged group (n = 12) and 7.9 h (IQR, 7.6-8.6) for the control group (n = 12; p = 0.01). In each group, three patients (25%; 95% CI 3.9-46%, p = 1) experienced a SAE. Markers of ischemia-reperfusion injury and oxidative stress in both perfusate and recipients were consistently low and showed no notable discrepancies between the two groups. All patients assigned to either the prolonged group or control group successfully received a liver graft perfused with either prolonged DHOPE or control DHOPE, respectively.

Interpretation

This first-in-human clinical trial demonstrates the safety and feasibility of DHOPE in prolonging the preservation time of donor livers to enable daytime transplantation. The ability to extend the preservation window to up to 20 h using hypothermic oxygenated machine preservation at a 10 °C temperature has the potential to reshape the landscape of liver transplantation.

Funding

University Medical Center Groningen, the Netherlands.

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.