Donor information based prediction of early allograft dysfunction and outcome in liver transplantation

Viability assessment of the liver during ex-situ machine perfusion prior to transplantation

PURPOSE OF REVIEW

In an attempt to reduce waiting list mortality in liver transplantation, less-than-ideal quality donor livers from extended criteria donors are increasingly accepted. Predicting the outcome of these organs remains a challenge. Machine perfusion provides the unique possibility to assess donor liver viability pretransplantation and predict postreperfusion organ function.

RECENT FINDINGS

Assessing liver viability during hypothermic machine perfusion remains challenging, as the liver is not metabolically active. Nevertheless, the levels of flavin mononucleotide, transaminases, lactate dehydrogenase, glucose and pH in the perfusate have proven to be predictors of liver viability. During normothermic machine perfusion, the liver is metabolically active and in addition to the perfusate levels of pH, transaminases, glucose and lactate, the production of bile is a crucial criterion for hepatocyte viability. Cholangiocyte viability can be determined by analyzing bile composition. The differences between perfusate and bile levels of pH, bicarbonate and glucose are good predictors of freedom from ischemic cholangiopathy.

SUMMARY

Although consensus is lacking regarding precise cut-off values during machine perfusion, there is general consensus on the importance of evaluating both hepatocyte and cholangiocyte compartments. The challenge is to reach consensus for increased organ utilization, while at the same time pushing the boundaries by expanding the possibilities for viability testing.

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.

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.

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.

Application of extended criteria donor grafts in liver transplantation for acute-on-chronic liver failure: A retrospective cohort study

BACKGROUND

There is no consensus on the usage of extended criteria donor (ECD) grafts in liver transplantation (LT) for acute-on-chronic liver failure (ACLF) patients.

AIM

To summarize the experience of using ECD livers in ACLF-LT.

METHODS

A retrospective cohort study was conducted, enrolling patients who underwent LT at the First Affiliated Hospital of Sun Yat-Sen University from January 2015 to November 2021. The patients were divided into ECD and non-ECD groups for analysis.

RESULTS

A total of 145 recipients were enrolled in this study, of which ECD and non-ECD recipients accounted for 53.8% and 46.2%, respectively. Donation after cardiac death (DCD) recipients accounted for the minority compared with donation after brain death (DBD) recipients (16.6% vs 83.4%). Neither overall survival nor graft survival significantly differed between ECD and non-ECD and DCD and DBD recipients. ECD grafts were associated with a significantly higher incidence of early allograft dysfunction (EAD) than non-ECD grafts (67.9% vs 41.8%, P = 0.002). Postoperative outcomes between DCD and DBD recipients were comparable (P > 0.05). ECD graft (P = 0.009), anhepatic phase (P = 0.034) and recipient gamma glutamyltransferase (P = 0.016) were independent risk factors for EAD. Recipient preoperative number of extrahepatic organ failures > 2 (P = 0.015) and intraoperative blood loss (P = 0.000) were independent predictors of poor post-LT survival.

CONCLUSION

Although related to a higher risk of EAD, ECD grafts can be safely used in ACLF-LT. The main factors affecting post-LT survival in ACLF patients are their own severe preoperative disease and intraoperative blood loss.

The Role of Donor Gamma-Glutamyl Transferase as a Risk Factor for Early Graft Function after Liver Transplantation

BACKGROUND

Growing interest has been recently reported in the potential detrimental role of donor gamma-glutamyl transferase (GGT) peak at the time of organ procurement regarding the risk of poor outcomes after liver transplantation (LT). However, the literature on this topic is scarce and controversial data exist on the mechanisms justifying such a correlation. This study aims to demonstrate the adverse effect of donor GGT in a large European LT cohort regarding 90-day post-transplant graft loss.

METHODS

This is a retrospective international study investigating 1335 adult patients receiving a first LT from January 2004 to September 2018 in four collaborative European centers.

RESULTS

Two different multivariable logistic regression models were constructed to evaluate the risk factors for 90-day post-transplant graft loss, introducing donor GGT as a continuous or dichotomous variable. In both models, donor GGT showed an independent role as a predictor of graft loss. In detail, the log-transformed continuous donor GGT value showed an odds ratio of 1.46 (95% CI = 1.03-2.07; p = 0.03). When the donor GGT peak value was dichotomized using a cut-off of 160 IU/L, the odds ratio was 1.90 (95% CI = 1.20-3.02; p = 0.006). When the graft-loss rates were investigated, significantly higher rates were reported in LT cases with donor GGT ≥160 IU/L. In detail, 90-day graft-loss rates were 23.2% vs. 13.9% in patients with high vs. low donor GGT, respectively (log-rank p = 0.004). Donor GGT was also added to scores conventionally used to predict outcomes (i.e., MELD, D-MELD, DRI, and BAR scores). In all cases, when the score was combined with the donor GGT, an improvement in the model accuracy was observed.

CONCLUSIONS

Donor GGT could represent a valuable marker for evaluating graft quality at transplantation. Donor GGT should be implemented in scores aimed at predicting post-transplant clinical outcomes. The exact mechanisms correlating GGT and poor LT outcomes should be better clarified and need prospective studies focused on this topic.

Gamma-glutamyltransferase predicts macrovesicular liver graft steatosis - an analysis of discarded liver allografts in Finland

OBJECTIVE

Liver-transplantation activity is limited by the shortage of grafts. Donor-liver macrovesicular steatosis predisposes to ischemia-reperfusion injury and is associated with reduced graft survival. The increasing prevalence of fatty-liver disease underlines the importance of identifying macrovesicular steatosis in potential donor livers. We analyzed liver grafts discarded for transplantation, and particularly the role of gamma-glutamyltransferase (GGT) in predicting graft steatosis.

METHODS

One-hundred sixty rejected cadaveric-donor liver grafts were studied. Donor selection was based on clinical data, and macroscopic graft inspection. Discarded grafts were biopsied at procurement of non-liver organs.

RESULTS

The most common reasons for discarding the graft were abnormal liver tests, ultrasound-verified steatosis and history of harmful alcohol use. GGT correlated moderately with macrovesicular steatosis (r = 0.52, p < 0.001), but poorly with microvesicular steatosis (r = 0.36, p < 0.001). Increased correlation between GGT and macrovesicular steatosis was observed among alcohol abusers (r = 0.67, p < 0.001). Area under the curve (AUC) of GGT for predicting >30% macrovesicular steatosis was 0.79 (95% CI 0.71-0.88), and for >60% steatosis, 0.79 (95% CI 0.68-0.90). The optimal GGT-cut off for detecting >30% and >60% macrovesicular steatosis were, respectively, 66 U/L (sensitivity 76% and specificity 68%) and 142 U/L (sensitivity 66% and specificity 83%). Among alcohol users, a GGT value >90 U/L showed 100% sensitivity for >60% macrovesicular steatosis. AUC for GGT in predicting fibrosis Stages 2-4 was 0.82 (95% CI 0.71-0.92, p < 0.001, optimal cut off 68, sensitivity 92%, specificity 61%).

CONCLUSIONS

Abnormal liver values, steatosis and harmful alcohol use were the main reasons for discarding liver-graft offers in Finland. GGT proved useful in predicting moderate and severe liver graft macrovesicular steatosis.

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.

Predictive value of portal fibrosis and inflammation in transplanted liver grafts treated with hypothermic oxygenated perfusion

BACKGROUND

Hypothermic oxygenated perfusion (HOPE) has become widespread for the preservation of liver grafts, making tangled the relationship among the use of extended criteria donors (ECD), graft histology and transplant outcome.

AIMS

To prospectively validate the impact of the graft histology on transplant outcome in recipient receiving liver grafts from ECD after HOPE.

METHODS

Ninety-three ECD grafts were prospectively enrolled; 49 (52.7 %) were perfused with HOPE according to our protocols. All clinical, histological and follow-up data were collected.

RESULTS

Grafts with portal fibrosis stage ≥ 3 according to Ishak's (evaluated with Reticulin stain) had a significantly higher incidence of early allograft dysfunction (EAD) and 6-month-dysfunction (p = 0.026 and p = 0.049), with more days in Intensive Care Unit (p = 0.050). Lobular fibrosis correlated with post-liver transplant kidney function (p = 0.019). Moderate-to-severe chronic portal inflammation was correlated with graft survival on both multivariate and univariate analyses (p < 0.001), but this risk factor is sensibly reduced by the execution of HOPE.

CONCLUSIONS

The use of liver grafts with portal fibrosis stage ≥ 3 implies a higher risk of post-transplant complications. Portal inflammation represents an important prognostic factor as well, but the execution of HOPE represents a valid tool to improve graft survival.

The role of normothermic machine perfusion (NMP) in the preservation of ex-vivo liver before transplantation: A review

The discrepancy between the number of patients awaiting liver transplantation and the number of available donors has become a key issue in the transplant setting. There is a limited access to liver transplantation, as a result, it is increasingly dependent on the use of extended criteria donors (ECD) to increase the organ donor pool and address rising demand. However, there are still many unknown risks associated with the use of ECD, among which preservation before liver transplantation is important in determining whether patients would experience complications survive after liver transplantation. In contrast to traditional static cold preservation of donor livers, normothermic machine perfusion (NMP) may reduce preservation injury, improve graft viability, and potentially ex vivo assessment of graft viability before transplantation. Data seem to suggest that NMP can enhance the preservation of liver transplantation to some extent and improve the early outcome after transplantation. In this review, we provided an overview of NMP and its application in ex vivo liver preservation and pre-transplantation, and we summarized the data from current clinical trials of normothermic liver perfusion.

Evaluation of red blood cell transfusion threshold in the management of brain-dead organ donors

The disparity between the demand and supply of organs has necessitated an expansion of the criteria for organ donation. Consequently, numerous guidelines have been proposed for managing brain-dead organ donors (BDODs) to improve their organ function and the organ procurement rate. Therefore, we aimed to evaluate the previously recommended threshold for red blood cell transfusion in BDODs. Medical records of BDODs were retrospectively reviewed from January 2012 to December 2021. We enrolled BDODs who stayed for more than 24 hours at an hospital organ procurement organization. We analyzed their organ function and the rate of organ procurement according to the hemoglobin concentration. A total of 111 BDODs were enrolled and divided into the following 2 groups: hemoglobin (Hb) ≥ 10 g/dL (45.0 %) and Hb < 10 g/dL (55.0 %). There were no significant differences between the groups in the total bilirubin, creatinine, arterial blood lactate, and the rate of organ procurement. A correlation analysis did not reveal any association between the hemoglobin concentration and organ function of the BDODs. Hemoglobin concentration of 10 g/dL cannot be considered a threshold for red blood cell transfusion. Furthermore, organ function is not correlated with a hemoglobin concentration > 7 g/dL. Restrictive transfusion strategy is appropriate for BDOD management.

Updated Views on Neutrophil Responses in Ischemia-Reperfusion Injury

Ischemia-reperfusion injury is an inevitable event during organ transplantation and represents a primary risk factor for the development of early graft dysfunction in lung, heart, liver, and kidney transplant recipients. Recent studies have implicated recipient neutrophils as key mediators of this process and also have found that early innate immune responses after transplantation can ultimately augment adaptive alloimmunity and affect late graft outcomes. Here, we discuss signaling pathways involved in neutrophil recruitment and activation after ischemia-mediated graft injury in solid organ transplantation with an emphasis on lung allografts, which have been the focus of recent studies. These findings suggest novel therapeutic interventions that target ischemia-reperfusion injury-mediated graft dysfunction in transplant recipients.

High visceral adipose tissue area is independently associated with early allograft dysfunction in liver transplantation recipients: a propensity score analysis

OBJECTIVES

To evaluate the association between adipose tissue distribution and early allograft dysfunction (EAD) in liver transplantation (LT) recipients.

METHODS

A total of 175 patients who received LT from April 2015 to September 2020 were enrolled in this retrospective study. The areas of abdominal adipose tissue and skeletal muscle of all patients were measured based on the preoperative CT images. The appropriate statistical methods including the propensity score-matched (PSM) analysis were performed to identify the association between adipose tissue distribution and EAD.

RESULTS

Of 175 LT recipients, 55 patients (31.4%) finally developed EAD. The multivariate logistic analysis revealed that preoperative serum albumin (odds ratio (OR) 0.34, 95% confidence interval (CI) 0.17-0.70), platelet-lymphocyte ratio (OR 2.35, 95% CI 1.18-4.79), and visceral adipose tissue (VAT) area (OR 3.17, 95% CI 1.56-6.43) were independent associated with EAD. After PSM analysis, VAT area was still significantly associated with EAD (OR 3.95, 95% CI 1.16-13.51). In survival analysis, no significant difference was identified in one-year graft failure (log-rank: p = 0.487), and conversely result was identified in overall survival (OS) (log-rank: p = 0.012; hazard ratio (HR) 4.10, 95% CI 1.27-13.16).

CONCLUSIONS

LT recipients with high VAT area have higher risk for the occurrence of EAD, and high VAT area might have certain clinical value for predicting the poor OS of patients. For LT candidates with large amount of VAT, the clinicians can take clinical interventions by suggesting physical and nutritional treatments to improve outcomes after LT.

Are short-term complications associated with poor allograft and patient survival after liver transplantation? A systematic review of the literature and expert panel recommendations

BACKGROUND

Maximizing patient and allograft survival after liver transplant (LT) is important from both a patient care and organ utilization perspective. Although individual studies have addressed the effects of short-term post-LT complications on a limited scale, there has not been a systematic review of the literature formally assessing the potential effects of early complications on long-term outcomes.

OBJECTIVES

To identify whether short-term complications after LT affect allograft and overall survival, to identify short-term complications of particular clinical interest and significance, and to provide recommendations to improve post-LT graft and patient survival.

DATA SOURCES

Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central.

METHODS

A systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel.

RESULTS

The literature review and analysis provided show that short-term complications have a large impact on allograft and patient survival after LT. The complications with the strongest effect on survival are acute kidney injury (AKI), biliary complications, and early allograft dysfunction (EAD).

CONCLUSION

This panel recommends taking measures to reduce the risk and incidence of short-term complications post-LT. Clinicians should pay particular attention to preventing or ameliorating AKI, biliary complications, and EAD (Quality of evidence; Moderate | Grade of Recommendation; Strong).

How useful is the machine perfusion in liver transplantation? An answer from a national survey

Machine perfusion (MP) has been shown worldwide to offer many advantages in liver transplantation, but it still has some gray areas. The purpose of the study is to evaluate the donor risk factors of grafts, perfused with any MP, that might predict an ineffective MP setting and those would trigger post-transplant early allograft dysfunction (EAD). Data from donors of all MP-perfused grafts at six liver transplant centers have been analyzed, whether implanted or discarded after perfusion. The first endpoint was the negative events after perfusion (NegE), which is the number of grafts discarded plus those that were implanted but lost after the transplant. A risk factor analysis for NegE was performed and marginal grafts for MP were identified. Finally, the risk of EAD was analyzed, considering only implanted grafts. From 2015 to September 2019, 158 grafts were perfused with MP: 151 grafts were implanted and 7 were discarded after the MP phase because they did not reach viability criteria. Of 151, 15 grafts were lost after transplant, so the NegE group consisted of 22 donors. In univariate analysis, the donor risk index >1.7, the presence of hypertension in the medical history, static cold ischemia time, and the moderate or severe macrovesicular steatosis were the significant factors for NegE. Multivariate analysis confirmed that macrosteatosis >30% was an independent risk factor for NegE (odd ratio 5.643, p = 0.023, 95% confidence interval, 1.27–24.98). Of 151 transplanted patients, 34% experienced EAD and had worse 1- and 3-year-survival, compared with those who did not face EAD (NoEAD), 96% and 96% for EAD vs. 89% and 71% for NoEAD, respectively (p = 0.03). None of the donor/graft characteristics was associated with EAD even if the graft was moderately steatotic or fibrotic or from an aged donor. For the first time, this study shows that macrovesicular steatosis >30% might be a warning factor involved in the risk of graft loss or a cause of graft discard after the MP treatment. On the other hand, the MP seems to be useful in reducing the donor and graft weight in the development of EAD.

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.

Prolyl Hydroxylase Inhibition Mitigates Allograft Injury During Liver Transplantation

BACKGROUND

Ischemia and reperfusion injury (IRI) determines primary allograft function after liver transplantation (LT). Primary graft dysfunction (PGD) is associated with increased morbidity and impaired graft survival and can eventually progress to graft failure requiring retransplantation. Hypoxia-inducible transcription factor-prolyl hydroxylase containing enzymes (PHD1, PHD2, and PHD3) are molecular oxygen sensors, which control the adaptive hypoxia response through the hypoxia-inducible factor (HIF). In this study, we have investigated pharmacological activation of the HIF pathway through inhibition of PHDs as a strategy to reduce PGD after LT.

METHODS

Primary rat hepatocytes were isolated and the impact of the pan-PHD small-molecule inhibitor ethyl-3,4-dihydroxybenzoate (EDHB) on HIF-1 and its downstream target gene expression assessed. Subsequently, various rodent models of segmental warm liver ischemia and reperfusion and orthotopic LT were applied to study the impact of EDHB on normothermic or combined cold and warm liver IRI. Liver enzyme levels and histology were analyzed to quantify hepatic IRI.

RESULTS

In vitro, EDHB induced HIF-1 signaling and significantly upregulated its downstream target heme-oxygenase 1 in primary rat hepatocytes. In vivo, after establishment of the optimal EDHB pretreatment conditions in a murine IRI model, EDHB pretreatment significantly mitigated hepatic IRI after warm segmental liver ischemia and reperfusion and allograft injury after orthotopic LT in rats. Mechanistically, EDHB stabilized HIF-1 in the liver and subsequently increased hepatoprotective heme-oxygenase 1 levels, which correlated with reduced hepatic IRI in these models.

CONCLUSIONS

This proof-of-concept study establishes a strong therapeutic rationale for targeting PHDs with small-molecule inhibitors to mitigate PGD after LT.

Prognostic value of protein biomarkers in liver transplantation: A systematic review

Liver transplantation is currently the preferred method for the treatment of advanced liver disease and early-stage hepatocellular carcinoma (HCC). Although advances in surgical techniques, immunosuppressive drugs and postoperative management have reduced the incidence of postoperative complications, how to effectively predict or diagnose postoperative complications earlier and reduce their incidence is still a clinical concern. We performed a comprehensive proteomics literature research to identified protein biomarkers in complications after liver transplantation. Seventeen studies met the inclusion criteria including ischemia reperfusion injury (IRI) (n = 4), acute rejection (AR) (n = 4), renal dysfunction (n = 4), HCC recurrence (n = 2), primary graft dysfunction (PGD) (n = 1), infection (n = 1), and liver fibrosis (n = 1). A total of 625 differentially expressed proteins (DEPs) have been reported between postoperative complications and controls, of which 63 have been validated by quantitative protein expression and 26 have been reported by at least two studies and showed consistently changes. The results of the bioinformation analysis show that the immune system, especially the innate immune system and cytokine signaling in immune system, is an important protein-mediated pathway that affects the prognosis of liver transplantation.

Evaluating Outcomes Related to Donor and Recipient Metabolic Environment: Macrosteatotic Allografts and Nonalcoholic Steatohepatitis

The increasing prevalence of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) affects both recipient and donor populations in liver transplantation. Presently, it is unclear whether transplantation of macrosteatotic allografts is affected by the metabolic milieu of liver transplant recipients. This study investigates fatty liver disease at the intersection of donor and recipient. A retrospective review of the Organ Procurement and Transplantation database identified 5167 NASH and 26,289 non-NASH transplant recipients who received transplants from January 1, 2004, to June 12, 2020. A total of 12,569 donors had allografts with no macrosteatosis (<5%), 16,140 had mild macrosteatosis (5%-29%), and 2747 had moderate to severe macrosteatosis (≥30%). Comparing recipients with NASH to propensity score-matched (PSM) recipients without NASH demonstrated noninferior graft and patient survival up to 10 years in patients with NASH. Similar trends were observed in subgroup analyses of transplants within each strata of allograft macrosteatosis. Assessing allograft macrosteatosis specifically in the NASH population demonstrated that allografts with ≥30% macrosteatosis were associated with reduced early graft survival (30 days, 93.32% versus 96.54% [P = 0.02]; 1 year, 84.53% versus 88.99% [P = 0.05]) compared with PSM grafts with <30% macrosteatosis. Long-term graft survival at 5 and 10 years, however, was similar. The use of carefully selected macrosteatotic allografts can be successful in both recipients with NASH and recipients without NASH. The metabolic environment of patients with NASH does not appear to adversely affect outcomes with regard to the allograft when controlled for numerous confounders. It is, however, important to remain cognizant of the potential for high-risk macrosteatotic allografts to negatively affect outcomes.

Re-thinking of T-tube use in whole liver transplantation: an analysis on the risk of delayed graft function

The liver–gut axis has been identified as crucial mediator of liver regeneration. Thus, the use of a T-tube in liver transplantation (LT), which interrupts the enterohepatic bile circulation, may potentially have a detrimental effect on the early allograft functional recovery. We retrospectively analyzed a cohort of 261 patients transplanted with a whole liver graft, with a duct-to-duct biliary anastomosis, who did not develop any surgical complication within postoperative day 14. Early allograft dysfunction (EAD) was defined according to the criteria of Olthoff et al. (EAD-O), and graded according to the Model for Early Allograft Function (MEAF) score. EAD-O developed in 24.7% of recipients and the median MEAF score was 4.0 [interquartile range 2.9–5.5]. Both MEAF and EAD predicted 90-day post-LT mortality. A T-tube was used in 49.4% of cases (n = 129). After a propensity score matching for donor age, cold and warm ischemia time, donor risk index, balance of risk score, Child–Pugh class C, and MELD score, the T-tube group showed a significantly higher prevalence of EAD-O and value of MEAF than the no-T-tube group (EAD-O: 29 [34.1%] vs 16 [19.0%], p = 0.027; MEAF 4.5 [3.5–5.7] vs 3.7 [2.9–5.0], p = 0.014). In conclusion, T-tube use in LT may be a risk factor for EAD and higher MEAF, irrespective of graft quality and severity of pre-LT liver disease.

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 \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\le $$\end{document}≤ 1.57 = 2.5, GRWR \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\ge $$\end{document}≥ 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.

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.

Effect of Aprotinin on Liver Injury after Transplantation of Extended Criteria Donor Grafts in Humans: A Retrospective Propensity Score Matched Cohort Analysis

The number of patients awaiting liver transplantation still widely exceeds the number of donated organs available. Patients receiving extended criteria donor (ECD) organs are especially prone to an aggravated ischemia reperfusion syndrome during liver transplantation leading to massive hemodynamic stress and possible impairment in organ function. Previous studies have demonstrated aprotinin to ameliorate reperfusion injury and early graft survival. In this single center retrospective analysis of 84 propensity score matched patients out of 274 liver transplantation patients between 2010 and 2014 (OLT), we describe the association of aprotinin with postreperfusion syndrome (PRS), early allograft dysfunction (EAD: INR 1,6, AST/ALT > 2000 within 7–10 days) and recipient survival. The incidence of PRS (52.4% vs. 47.6%) and 30-day mortality did not differ (4.8 vs. 0%; p = 0.152) but patients treated with aprotinin suffered more often from EAD (64.3% vs. 40.5%, p = 0.029) compared to controls. Acceptable or poor (OR = 3.3, p = 0.035; OR = 9.5, p = 0.003) organ quality were independent predictors of EAD. Our data do not support the notion that aprotinin prevents nor attenuates PRS, EAD or mortality.

The Lactate-to-Platelet Ratio: A Novel Predictor for Short-Term Early Allograft Failure After Liver Transplantation

BACKGROUND

Early allograft dysfunction (EAD) is a criterion to evaluate initial graft dysfunction associated with inferior graft survival and postoperative complications after liver transplantation (LT). This study defined the lactate-to-platelet ratio (LPR) as lactate level immediately post-LT/platelet count on postoperative day 1 and evaluated its association with EAD and short-term graft failure.

MATERIALS AND METHODS

This study reviewed 434 deceased-donor LTs from individuals with confirmed brain death between January 2008 and December 2014. The area under the curve (AUC) was used to compare the predictive capacity for 3-month graft survival between EAD and the LPR. Along with LPR, the risk factors for 3-month graft failure were analyzed by multivariate analysis.

RESULTS

EAD was reported in 127 patients (31%). The LPR in patients with EAD was significantly higher than that in patients without EAD (9.8 vs 5.9, P < .001). In the multivariate analysis, both the LPR (per 1.0 increase) and EAD were independent risk factors for 3-month graft failure (hazard ratio [HR] =1.03, P = .03; and HR = 9.14, P = .001). The comparison of the AUCs between the LPR and EAD showed no significant difference (0.79 vs 0.78, P = .84), whereas the combination of EAD and LPR had a better predictive capacity than EAD alone (0.86 vs 0.78, P < .001). The LPR showed an inverse relationship for predicting 3-month graft survival.

CONCLUSIONS

The LPR is a continuous parameter that enables prediction of initial graft function and estimation of the 3-month graft failure rate with the advantages of early availability and simple calculations.

Using Rotational Thromboelastometry to Identify Early Allograft Dysfunction after Living Donor Liver Transplantation

Background: Diagnostic tests for early allograft dysfunction (EAD) after living donor liver transplantation (LDLT) vary widely. We aimed to evaluate the predictive value of rotational thromboelastometry (ROTEM)-derived parameters in EAD. Materials and Methods: A total of 121 patients were reviewed. The definition of EAD proposed by Olthoff et al. included the presence of any of the following at postoperative day 7: bilirubin level ≥ 10 mg/dL, INR ≥ 1.6, or serum AST or ALT levels > 2000 IU/L. All patients underwent ROTEM assay, which consisted of an extrinsically activated thromboelastometric test (EXTEM) before and 24 h after LDLT. Results: The 1-year/2-year OS were 68.%8/64.5% and 94.4%/90.8% for the EAD and non-EAD groups, respectively (p = 0.001). Two independent risks were identified for EAD, the postoperative clotting time (CT, p = 0.026) and time to maximum clot firmness (maximum clot firmness (MCF)-t, p = 0.009) on the EXTEM. CT yielded a specificity of 82.0% and negative predictive value of 83.0%, and MCF-t displayed a specificity of 76.4% and negative predictive value of 81.9% in diagnosing EAD. The use of the 24 h post-LDLT ROTEM increased the effectiveness of predicting overall survival (OS) compared to using the Olthoff’s EAD criteria alone (p < 0.001). Conclusion: We conclude that CT and MCF on EXTEM were independent predictors of EAD. The 24 h post-LDLT ROTEM can be used with conventional laboratory tests to diagnose EAD. It increases the effectiveness of predicting OS.

Early Allograft Dysfunction After Liver Transplantation With Donation After Circulatory Death and Brain Death Grafts: Does the Donor Type Matter?

Background.

Early allograft dysfunction (EAD) after liver transplantation has been associated with long-term reduced graft and patient survival.

Methods.

In this single-center cohort study, we aimed to compare incidence, risk factors, and outcomes in liver transplant recipients who developed EAD. Patients who received donation after circulatory death (DCD) or donation after brain death (DBD) grafts between January 2007 and December 2017 were included. EAD was defined as bilirubin of ≥10 mg/dL (171 μmol/L) or an international normalized ratio of ≥1.6 on postoperative day 7 or transaminases >2000 U\L in the first-week posttransplantation as previously described.

Results.

In our cohort of 1068 patients, incidence of EAD was 44%. EAD occurred more frequently in the DCD versus DBD group (71% versus 41%, P < 0.01). Overall, recipients who developed EAD showed a significantly lower graft and patient survival at 1, 3, and 5 y after transplantation (all P < 0.05). This was also the case for recipients of DBD grafts. However, for recipients of DCD grafts, patient and graft survival were not affected by the presence of EAD. For recipients of DBD grafts, donor age, body mass index (BMI) and gender, recipient BMI and model for end-stage liver disease score and warm and cold ischemia time were associated with EAD. For DCD recipients, donor BMI and cold ischemia time were associated with EAD.

Conclusions.

In our cohort study, EAD resulted in reduced long-term patient and graft survival only for DBD recipients but not for DCD recipients. Predictive markers for EAD were dependent on the donor type.

An Italian survey on the use of T-tube in liver transplantation: old habits die hard!

There is enough clinical evidence that a T-tube use in biliary reconstruction at adult liver transplantation (LT) does not significantly modify the risk of biliary stricture/leak, and it may even sustain infective and metabolic complications. Thus, the policy on T-tube use has been globally changing, with progressive application of more restrictive selection criteria. However, there are no currently standardized indications in such change, and many LT Centers rely only on own experience and routine. A nation-wide survey was conducted among all the 20 Italian adult LT Centers to investigate the current policy on T-tube use. It was found that 20% of Centers completely discontinued the T-tube use, while 25% Centers used it routinely in all LT cases. The remaining 55% of Centers applied a selective policy, based on criteria of technical complexity of biliary reconstruction (72.7%), followed by low-quality graft (63.6%) and high-risk recipient (36.4%). A T-tube use > 50% of annual caseload was not associated with high-volume Center status (> 70 LT per year), an active pediatric or living-donor transplant program, or use of DCD grafts. Only 10/20 (50%) Centers identified T-tube as a potential risk factor for complications other than biliary stricture/leak. In these cases, the suspected pathogenic mechanism comprised bacterial colonization (70%), malabsorption (70%), interruption of the entero-hepatic bile-acid cycle (50%), biliary inflammation due to an indwelling catheter (40%) and gut microbiota changes (40%). In conclusion, the prevalence of T-tube use among the Italian LT Centers is still relatively high, compared to the European trend (33%), and the potential detrimental effect of T-tube, beyond biliary stricture/leak, seems to be somehow underestimated.

Severity of early allograft dysfunction following donation after circulatory death liver transplantation: a multicentre study

Background

Early allograft dysfunction (EAD) is associated with decreased graft and patient survival rates. This study aimed to identify the severity of EAD and develop a predictive model for EAD after donation after circulatory death (DCD) liver transplantation (LT). Furthermore, the influence of operative time on EAD incidence was also evaluated.

Methods

In this retrospective, multicentre cohort study, nomograms were established based on a single-centre training cohort (n=321) and validated in a 3-center validation cohort (n=501).

Results

The incidence rate of EAD was 46.4% (149/321) in the training cohort and 40.5% (203/501) in the validation cohort. Of the 149 EAD patients in the training cohort, 77 patients with either elevated alanine aminotransferase (ALT) or aspartate aminotransferase (AST) were classified as having EAD type A, and the rest of the EAD patients were classified as having EAD type B. Recipients with EAD type B had lower graft and patient survival rates than recipients with EAD type A (P=0.043 and 0.044, respectively). We further developed a nomogram to predict EAD (graft weight, cold ischemia time, donor age, model for end-stage liver disease (MELD) score) and another nomogram to predict EAD type B (graft weight, cold ischemia time, MELD score). The nomograms for the prediction of EAD and EAD type B had good discrimination [concordance index (C-index) =0.712 (0.666-0.758), 0.707 (0.641-0.773)] and calibration [Hosmer-Lemeshow (HL) P=0.384, P=0.425] in the validation cohort. An increased operative time (>6 h) was associated with increased EAD and EAD type B incidence in the high-risk group (P=0.005, P=0.020, respectively).

Conclusions

EAD type B was associated with decreased graft and patient survival rates. The novel nomograms effectively predicted the incidence of EAD and EAD type B in DCD LT patients.

Ischemia-reperfusion injury and its relationship with early allograft dysfunction in liver transplant patients

Ischemia-reperfusion injury (IRI) is believed to contribute to graft dysfunction after liver transplantation (LT). However, studies on IRI and the impact of early allograft dysfunction (EAD) in IRI grafts are limited. Histological IRI was graded in 506 grafts from patients who had undergone LT and classified based on IRI severity (no, minimal, mild, moderate, and severe). Of the 506 grafts, 87.4% had IRI (no: 12.6%, minimal: 38.1%, mild: 35.4%, moderate: 13.0%, and severe: 0.8%). IRI severity correlated with the incidence of EAD and graft survival at 6 months. Longer cold/warm ischemia time, recipient/donor hypertension, and having a male donor were identified as independent risk factors for moderate to severe IRI. Among 70 grafts with moderate to severe IRI, 42.9% of grafts developed EAD, and grafts with EAD had significantly inferior survival compared to grafts without EAD. Longer cold ischemia time and large droplet macrovesicular steatosis (≥20%) were identified as independent risk factors for EAD. Our study demonstrated that increased IRI severity was correlated with inferior short-term graft outcomes. Careful consideration of IRI risk factors during donor-recipient matching may assist in optimizing graft utilization and LT outcomes. Furthermore, identification of risk factors of IRI-associated EAD may guide patient management and possible timely graft replacement.

Contrast-enhanced ultrasonography to evaluate risk factors for short-term and long-term outcomes after liver transplantation: A pilot prospective study

PURPOSE

To evaluate whether Doppler ultrasonography (DUS) and contrast-enhanced ultrasonography (CEUS) can identify liver donation after brain death (DBD) and cardiac death (DCD) with the risk of developing short-term primary graft dysfunction (PGD) or arterial and biliary complications within 1 year.

MATERIALS AND METHODS

Consecutive DBD and DCD donors who underwent DUS/CEUS examinations before surgical procurement from February 2016 to June 2018 at our institution were included. The US and CEUS images of each donor liver were analysed, and the parameters were recorded.

RESULTS

The mean time for US examination was 32 min (range, 20-59 min), and all donors tolerated the examination well. In terms of short-term outcomes, among the 52 eligible donor livers, 20 (38.5 %) of their recipients developed PGD. The multivariable analysis showed that decreased enhancement of donor livers on CEUS (OR = 15.976, 95 % CI: 1.652-154.628, P = 0.017) and high recipient model for end-stage liver disease (MELD) scores (OR = 1.050, 95 % CI: 1.004-1.099, P = 0.034) before liver transplantation (LT) were independent factors of PGD. In contrast, for long-term complications, among the 48 eligible donor livers, 16 (33.3 %) developed arterial or biliary complications within 1 year. The multivariable analysis did not show any independent factors of arterial or biliary complications within 1 year.

CONCLUSIONS

A decrease in enhancement on CEUS is an independent risk factor for poor short-term outcomes of LT. CEUS may be promising for predicting post-LT outcomes of critically ill donors effectively and safely by evaluating the haemodynamic changes in DBD and DCD donor livers.

A Novel Preservation Solution Containing Quercetin and Sucrose for Porcine Kidney Transplantation

In organ transplantation, the University of Wisconsin (UW) solution has been the gold standard for organ preservation. Quercetin (Que) has numerous antioxidant and anti-inflammatory activities, and sucrose (Suc) may be effective for cold storage (CS). This study aimed to investigate the in vitro protective effect of Que and Suc on cold injury to the kidney and to determine whether Que + Suc could improve ischemia-reperfusion injury during CS and hypothermic oxygenated perfusion (HOPE) in autologous transplantation models.

METHODS

BHK-21 cells were stored at 4°C for 3 days in UW solution for CS/machine perfusion (CS/MP-UW) with Que (33.1 μM, 3.3 μM, 0.33 μM) and Suc (0.1 M). In a porcine model of renal autologous transplantation, left kidney grafts were preserved under 3 conditions: group 1, CS preservation for 24 hours; group 2, CS preservation for 22 hours and HOPE with CS/MP-UW solution for 2 hours; and group 3, identical preservation as group 2, with Que and Suc added to the solution. Animals were euthanized on day 7 after autologous transplantation.

RESULTS

After 3 days of CS preservation, the CS/MP-UW solution with Que (33.1 μM, 3.3 μM) and Suc showed significant cell protection against cold injury. In the porcine model of renal autologous transplantation, the last blood Cre level and the blood lipid hydroperoxide on posttransplantation day 2 were significantly different between group 1 and group 3. Moreover, the total endothelial, glomerular, tubular, interstitial (EGTI) histology score in the kidney tissue was also significantly different. Regarding the change in renal resistance in HOPE, the decrease observed in group 3 was significantly larger than that in group 2.

CONCLUSIONS

Our results suggest that the addition of Que and Suc to a UW solution can improve kidney preservation and could potentially enhance the outcome of kidney transplantation.

Clear mortality gap caused by graft macrosteatosis in Chinese patients after cadaveric liver transplantation

BACKGROUND

Liver transplantation (LT) is one of the most effective surgical treatment for patients with end-stage liver disease. Steatosis is a contributor for inferior graft quality. But its impact and safety on transplantation was less assessed in Chinese patients.

METHODS

Graft steatosis and related information involved in recipients, donors and surgical procedures were retrospectively collected from 239 patients.

RESULTS

Donor macrosteatosis (MaS) caused about 2.14 and 2.80 folds of increment on patient and graft mortality. Dose-response analysis revealed prominent risk of grafts on overall patient/organ mortality when MaS content exceeded 10% (P<0.05). Noteworthy, deaths were only observed in MaS group when concurrent with extremely higher post-transplant alanine aminotransferase (ALT, 64%). However, microsteatosis (MiS) grafts didn't affect outcomes after LT. In a cohort of Chinese patients, MaS had comprehensive effects on post-transplant outcomes with relatively lower safety threshold at 10%. Mortality gap caused by MaS grafts was observed in patients with severer ischemia reperfusion injury.

CONCLUSIONS

Our study revealled the graft MaS affected the post-transplant outcomes in lower risk cutoff in Chinese patients. Further study is worthy to validate these results and investigate inner mechanism under the phenomenon.

Association of Perfusion Characteristics and Posttransplant Liver Function in Ischemia-Free Liver Transplantation

It has been shown that normothermic machine perfusion (NMP), a novel preservation method, is able to assess and resuscitate liver grafts with risk factors. However, there is no consistent criteria for the assessment of liver grafts with NMP. Ischemia-free liver transplantation (IFLT) includes innovative surgical techniques and NMP, which can protect liver grafts from ischemia throughout organ procurement, preservation, and implantation. In our center, 28 human livers from donation after brain death donors were subjected to IFLT between July 2017 and October 2018. The correlation between posttransplant liver function tests with the perfusion parameters, blood gas analysis of perfusate, and bile biochemistry were analyzed. During the preservation phase, the vascular flow was stable, and the lactate level decreased rapidly. The transaminase release in the perfusate was low but stable, whereas the glucose level remained high. The perfusate lactate and aspartate aminotransferase (AST) levels at 1 hour of perfusion were correlated with the posttransplant peak AST level. There were negative correlations between the portal vein and hepatic artery flows at the end of perfusion and the peak transaminase levels within 7 days after transplantation. In conclusion, during IFLT, NMP is able to bridge the liver grafts from donors to recipients and can allow the assessment of liver function by perfusion characteristics.

Prognostic value of endogenous and exogenous metabolites in liver transplantation

Liver transplantation has been widely accepted as an effective intervention for end-stage liver diseases and early hepatocellular carcinomas. However, a variety of postoperative complications and adverse reactions have baffled medical staff and patients. Currently, transplantation monitoring relies primarily on nonspecific biochemical tests, whereas diagnosis of multiple complications depends on invasive pathological examination. Therefore, a noninvasive monitoring method with high selectivity and specificity is desperately needed. This review summarized the potential of endogenous small-molecule metabolites as biomarkers for assessing graft function, ischemia-reperfusion injury and liver rejection. Exogenous metabolites, mainly those immunosuppressive agents with high intra- and inter-individual variability, were also discussed for transplantation monitoring.

Long-term Outcomes After Controlled Oxygenated Rewarming of Human Livers Before Transplantation

Controlled oxygenated rewarming (COR) has been shown to be a feasible and safe method in clinical practice and to reduce peak serum transaminases after liver transplantation. This study aimed to demonstrate further clinical experience of this method of now 18 clinical liver transplantations utilizing COR and demonstrate the long-term results.

Methods

In this extended series of 18 patients, cold-stored livers were subjected to machine-assisted slow COR for ≈120 minutes before transplantation. A cohort of 178 patients transplanted during the same period with similar clinical characteristics were used for comparison of key outcomes.

Results

All livers were perfused in accordance to the COR protocol without incidences and transplanted successfully. Early allograft dysfunction was observed in 2 (11.1%) cases after COR. Liver elasticity measurements indicated normal healthy liver parenchyma at the last follow-up. Graft survival demonstrated excellent outcomes after COR. The 1-, 3-, and 5-year patient survival rates were 100%, 100%, and 93.8% compared with 84.5%, 82.0%, and 75.8% in the control group (P = 0.12).

Conclusions

The present study demonstrates excellent clinical outcomes after COR before liver transplantation. Comparison with a control cohort shows superiority of graft survival. Further evidence is needed to assess this promising method to improve organ preservation, finally.

The histological assessment of liver fibrosis in grafts from extended criteria donors predicts the outcome after liver transplantation: A retrospective study

BACKGROUND

The use of extended criteria donors (ECD) in liver transplantation is increasing due to the organ shortage. Histological evaluation of the liver graft in the context of procurement is an important tool for extending the donor pool without affecting the quality of the transplanted organs. Macrovesicular steatosis is widely accepted as predictor of early allograft dysfunction (EAD), while other features, such as portal fibrosis, are poorly studied.

AIM

To identify morphological features, other than macrovesicular steatosis, that may affect recipients' outcome.

METHODS

Between 2014 and 2016, 132 donors with extended criteria underwent pre-transplant liver biopsy during procurement. Histological variables of the graft, donors'/recipients' clinical data, EAD and patient/graft survival were registered.

RESULTS

The recipients who received a graft with histological-proven portal fibrosis had a significant lower patient and graft survival in comparison to patients without fibrosis (P = 0.044 and P = 0.039, respectively). Donors' dyslipidemia was significantly associated with the occurrence of EAD (P = 0.021). When dyslipidemia was combined with histological liver fibrosis a 54.5% incidence of EAD was observed (P = 0.012).

CONCLUSIONS

The histological assessment of liver fibrosis in pre-transplant biopsy of ECD grafts, together with donor's clinical data, provides important information on recipients' outcome.

A two-circular RNA signature of donor circFOXN2 and circNECTIN3 predicts early allograft dysfunction after liver transplantation

Background

Early allograft dysfunction (EAD) following liver transplantation is associated with poor recipient and graft survival. In recent years, circular RNAs (circRNAs) have emerged as important components of endogenous RNAs. This study aims to explore the expression profile and predictive value of graft circular RNAs for EAD after liver transplantation.

Methods

RNA sequencing was conducted to identify the circRNA profile in donor liver tissues. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) was used to identify candidate circRNAs. A novel model combining circular RNA signature was established to predict EAD based on the multivariate analysis.

Results

A total of 442 circRNAs were differentially expressed between the EAD and non-EAD groups, of which, 223 were significantly upregulated and 219 were downregulated in the EAD group (Fold change >2, P<0.05). qRT-PCR validation indicated that circFOXN2 and circNECTIN3 levels in the EAD group were significantly lower than those in the non-EAD group (P=0.038, 0.024, respectively; n=115). Among the 115 recipients, 32 recipients with high circFOXN2 expression were classified as circular RNA signature A and the rest recipients with low circFOXN2 expression were categorized into circular RNA signature B (n=33, high circNECTIN3 expression) and C (n=50, low circNECTIN3 expression). The incidence rates of EAD in signature A, B and C were significantly different (3.1%, 21.2% and 42.0%, respectively; P=0.000). According to the multivariate analysis, a novel predictive model for EAD was developed based on CIT (P=0.000) and circular RNA signature (P=0.013). The novel model displayed a high predictive value for EAD with areas under the curve (AUC) of 0.870 (95% CI: 0.797-0.942).

Conclusions

Donor circFOXN2 and circNEXTIN3 were associated with the incidence of EAD. The novel model combing the two-circular RNA signature had a high predictive value for EAD.

Conceptual changes in small-for-size graft and small-for-size syndrome in living donor liver transplantation

Early series in living donor liver transplantation (LDLT) in adults demonstrated a lower safe limit of graft volume standard liver volume ratio 25%–45%. A subsequent worldwide large LDLT series proposed a 0.8 graft recipient weight ratio (GRWR) to define small-for-size graft (SFSG) in adult LDLT. Thereafter, researchers identified innate and inevitable factors including changes in liver volume during imaging studies and graft shrinkage due to perfusion solution. Although the definition of small-for-size syndrome (SFSS) advocated in the 2000s was mainly based on prolonged cholestasis and ascites output, the term SFSS was inadequate to describe clinical manifestations possibly caused by multiple factors. Thus, the term “early allograft dysfunction (EAD),” characterized by total bilirubin >10 mg/dL or coagulopathy with international normalized ratio >1.6 on day 7, has become prevalent to describe graft dysfunction including SFSS after LDLT. Although various efforts have been made to overcome EAD in LDLT, graft selection to maintain an expected GRWR >0.8 and full venous drainage, as well as inflow modulation using splenic artery ligation, have become standard in recent LDLT.

Heavy Water (D2O) Containing Preservation Solution Reduces Hepatic Cold Preservation and Reperfusion Injury in an Isolated Perfused Rat Liver (IPRL) Model

Background: Heavy water (D₂O) has many biological effects due to the isotope effect of deuterium. We previously reported the efficacy of D₂O containing solution (Dsol) in the cold preservation of rat hearts. Here, we evaluated whether Dsol reduced hepatic cold preservation and reperfusion injury. Methods: Rat livers were subjected to 48-hour cold storage in University of Wisconsin (UW) solution or Dsol, and subsequently reperfused on an isolated perfused rat liver. Graft function, injury, perfusion kinetics, oxidative stress, and cytoskeletal integrity were assessed. Results: In the UW group, severe ischemia and reperfusion injury (IRI) was shown by histopathology, higher liver enzymes leakage, portal resistance, and apoptotic index, oxygen consumption, less bile production, energy charge, and reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio (versus control). The Dsol group showed that these injuries were significantly ameliorated (versus the UW group). Furthermore, cytoskeletal derangement was progressed in the UW group, as shown by less degradation of α-Fodrin and by the inactivation of the actin depolymerization pathway, whereas these changes were significantly suppressed in the Dsol group. Conclusion: Dsol reduced hepatic IRI after extended cold preservation and subsequent reperfusion. The protection was primarily due to the maintenance of mitochondrial function, cytoskeletal integrity, leading to limiting oxidative stress, apoptosis, and necrosis pathways.

Risk factors, surgical complications and graft survival in liver transplant recipients with early allograft dysfunction

BACKGROUND

Early allograft dysfunction (EAD) is a severe complication after liver transplantation. The associated risk factors and complications have re-gained recent interest. This study investigated risk factors, survival and complications associated with EAD in a large liver transplant center in Latin America.

METHODS

Retrospective, unicenter, cohort, based on data from adult patients undergoing first deceased-donor liver transplant from January 2009 to December 2013. EAD was defined by one or more of the following: (i) bilirubin ≥10 mg/dL on postoperative day 7; (ii) international normalized ratio ≥1.6 on postoperative day 7, and (iii) alanine aminotransferase or aspartate aminotransferase >2000 IU/L within the first seven days after transplant.

RESULTS

A total of 602 patients were included; of these 34.2% developed EAD. Donor risk factors were male (P = 0.007), age between 50 and 59 years (P = 0.034), overweight (P = 0.028) or grade I obesity (P = 0.012), sodium >157 mmol/L (P = 0.002) and grade IV ischemia/reperfusion injury (P = 0.002). Cold ischemia time ≥10 h (P = 0.008) and warm ischemia time ≥40 min (P = 0.013) were the surgical factors. Male (P <0.001) was the only recipient protective factor. Compared with the non-EAD group, patients with EAD were submitted to more reoperations (24.3% vs. 13.4%, P = 0.001) and had higher graft loss rates (37.9% vs. 21.2%, P <0.001), with similar patient survival rates (P = 0.238).

CONCLUSIONS

EAD risk factors are related to donor, surgical procedure and recipient. Donor risk factors for EAD were male, age between 50 and 59 years, donor overweight or grade I obesity, sodium >157 mmol/L and grade IV ischemia/reperfusion injury. Cold ischemia time ≥10 h and warm ischemia time ≥40 min were the surgical risk factors. Male was the only recipient protective factor. Patients with EAD had higher reoperations and graft loss rates.

Transient Cold Storage Prior to Normothermic Liver Perfusion May Facilitate Adoption of a Novel Technology

Clinical adoption of normothermic machine perfusion (NMP) may be facilitated by simplifying logistics and reducing costs. This can be achieved by cold storage of livers for transportation to recipient centers before commencing NMP. The purpose of this study was to assess the safety and feasibility of post-static cold storage normothermic machine perfusion (pSCS-NMP) in liver transplantation. In this multicenter prospective study, 31 livers were transplanted. The primary endpoint was 30-day graft survival. Secondary endpoints included the following: peak posttransplant aspartate aminotransferase (AST), early allograft dysfunction (EAD), postreperfusion syndrome (PRS), adverse events, critical care and hospital stay, biliary complications, and 12-month graft survival. The 30-day graft survival rate was 94%. Livers were preserved for a total of 14 hours 10 minutes ± 4 hours 46 minutes, which included 6 hours 1 minute ± 1 hour 19 minutes of static cold storage before 8 hours 24 minutes ± 4 hours 4 minutes of NMP. Median peak serum AST in the first 7 days postoperatively was 457 U/L (92-8669 U/L), and 4 (13%) patients developed EAD. PRS was observed in 3 (10%) livers. The median duration of initial critical care stay was 3 days (1-20 days), and median hospital stay was 13 days (7-31 days). There were 7 (23%) patients who developed complications of grade 3b severity or above, and 2 (6%) patients developed biliary complications: 1 bile leak and 1 anastomotic stricture with no cases of ischemic cholangiopathy. The 12-month overall graft survival rate (including death with a functioning graft) was 84%. In conclusion, this study demonstrates that pSCS-NMP was feasible and safe, which may facilitate clinical adoption.

Analysis of Data from the Oxygen Persufflation in Liver Transplantation (OPAL) Study to Determine the Role of Factors Affecting the Hepatic Microcirculation and Early Allograft Dysfunction

Background

Adequate microcirculatory perfusion is essential for the provision of oxygen to the liver following transplantation. Data from the Oxygen Persufflation in Liver Transplantation (OPAL) study (ISRCTN00167887) were analyzed from liver transplants performed at a single center to determine the role of factors affecting the hepatic microcirculation and early allograft dysfunction (EAD).

Material/Methods

Retrospective data from 116 patients from the Oxygen Persufflation as Adjunction in Liver Transplantation (OPAL) study who underwent liver transplantation at a single center were analyzed. Oxygen saturation of hemoglobin (SO₂), relative capillary hemoglobin concentration (rHb), relative tissue blood flow (rBF) using laser Doppler flow measurements, and the Oxygen-to-See (O2C) spectrometry were measured and with post-transplant allograft function were analyzed using univariate and multivariate logistic regression statistics.

Results

Livers donors had a median donor risk index of 1.8. Most liver transplant recipients were men (60.3%), with a median age of 54 years (IQR, 23–68 years). Mean post-transplant 3-month survival was 90.5%. The EAD rate was 22.4%, the median SO₂ was 78% (IQR, 29.5–95.8%), the median rHb was 55.6 AU (IQR, 16.8–74.8 AU), and the median rBF was 110.1 AU (IQR, 35.8–406.8 AU). Multivariate logistic regression analysis showed that tissue SO₂ (p=0.01), body mass index (BMI) of the transplant recipient (p=0.002), serum alanine transaminase (ALT) of the donor (p=0.02), and portal blood flow (p=0.01) were predictive factors for EAD.

Conclusions

Non-invasive investigations of the liver microcirculation and hemoglobin oxygenation were shown to be predictive factors for EAD following liver transplantation.

Efficacy of IgM-enriched Immunoglobulin for Vasopressor-resistant Vasoplegic Shock After Liver Transplantation

BACKGROUND

Vasoplegia is a clinical condition typically manifested by cardiovascular instability unresponsive to the usual doses of inotropes or vasopressors. It can occur in a variety of clinical settings including liver transplantation (LT). Immunoglobulins have been used to treat sepsis-related vasoplegia. We performed a retrospective study to evaluate the efficacy of IgM-enriched immunoglobulin (IgMIg) on 30-day mortality and its ability to reverse vasoplegia in patients undergoing LT.

METHODS

Between May 2013 and November 2017, 473 LT were performed at our institution. We identified 21 patients who received IgMIg for 3 days to treat vasoplegia. Patients included in the study met the criteria for having vasoplegia and required noradrenaline administration greater than 1 μg·kg·min for more than 24 hours to maintain a mean arterial pressure of 70 mm Hg or greater. Procalcitonin and interleukin-6 (IL-6) levels were used as surrogate markers for inflammation and were measured at the beginning and end of IgM treatment.

RESULTS

After IgMIg administration, median noradrenaline infusion rates could be significantly reduced from 1.6 μg·kg·min (1.3-2 μg·kg·min) to 0.16 μg·kg·min (0.08-0.34 μg·kg·min) (P < 0.001). In addition, after treatment, procalcitonin levels decreased significantly from 44 ng/mL (24-158) to 26.1 ng/mL (10.9-48.7) (P < 0.001) and IL-6 levels decreased significantly from 63 pg/mL (29-102) to 20 pg/mL (11-20) (P < 0.001). Thirty-day morality was 14.3%.

CONCLUSIONS

The administration of IgMIg in patients with vasoplegia after LT is associated with a return of hemodynamic stability. Despite a predicted mortality of over 90% by Sepsis-Related Organ Failure Assessment score, the mortality rate of patients receiving IgMIg in our study was less than 20%.

Oxygen Persufflation in Liver Transplantation Results of a Randomized Controlled Trial

Oxygen persufflation has shown experimentally to favorably influence hepatic energy dependent pathways and to improve survival after transplantation. The present trial evaluated oxygen persufflation as adjunct in clinical liver preservation. A total of n = 116 adult patients (age: 54 (23–68) years, M/F: 70/46), were enrolled in this prospective randomized study. Grafts were randomized to either oxygen persufflation for ≥2 h (O2) or mere cold storage (control). Only liver grafts from donors ≥55 years and/or marginal grafts after multiple rejections by other centers were included. Primary endpoint was peak-aspartate aminotransferase (AST) level until post-operative day 3. Standard parameters including graft- and patient survival were analyzed by uni- and multivariate analysis. Both study groups were comparable except for a longer ICU stay (4 versus 3 days) of the donors and a higher recipient age (57 versus 52 years) in the O2-group. Serum levels of TNF alpha were significantly reduced after oxygen persufflation (p < 0.05). Median peak-AST values did not differ between the groups (O2: 580 U/l, control: 699 U/l). Five year graft- and patient survival was similar. Subgroup analysis demonstrated a positive effect of oxygen persufflation concerning the development of early allograft dysfunction (EAD), in donors with a history of cardiopulmonary resuscitation and elevated ALT values, and concerning older or macrosteatotic livers. This study favors pre-implantation O2-persufflation in concrete subcategories of less than optimal liver grafts, for which oxygen persufflation can be considered a safe, cheap and easy applicable reconditioning method.

Primary liver graft dysfunction and non-function: integrative literature review

Avoiding deaths in the waiting list for an organ is no longer the only focus of the transplant teams attention. Research and care in clinical practice has been increasingly focused on post transplant graft survival and functioning. In the present work, we performed an integrative literature review to identify the terminology used about liver graft dysfunction and non-function, as well as to investigate the incidence and risk factors of these clinical events. We chosen articles written in Portuguese, English and Spanish between 2012 and 2016, based on CINAHL, MEDLINE, Cochrane, LILACS, BDENF, IBECS, EMBASE and Web of Science. We selected 14 studies, in which we identified the incidence of hepatic graft dysfunction ranging from 7% to 27%. The terminology used to describe this clinical event was initial malfunction, graft hypofunction, marginal function or delay in function. The primary non-function of the liver graft was found in 1.4% to 8.4% of the patients, and the terminology used to describe the event was early dysfunction or graft loss. The risk factors found are related to donor, recipient, graft and transplant logistics variables. We conclude that knowledge of the different terminologies employed in the literature, related to dysfunction and primary non- function incidence, and of their risk factors are fundamental to qualify the control of the events, aiming to improve patients' survival after liver transplantation.

Efficacy and Safety of Steroid Therapy for Posttransplant Hyperbilirubinemia Caused by Early Allograft Dysfunction: A Randomized Controlled Trial

BACKGROUND Hyperbilirubinemia is a common event that occurs after liver transplantation. Hyperbilirubinemia is usually caused by early allograft dysfunction. Glucocorticoid is widely used for immunosuppression, but few studies have analyzed the effects of steroid therapy on posttransplantation hyperbilirubinemia. The aim of this study was to assess whether glucocorticoid was beneficial in treating hyperbilirubinemia caused by early allograft dysfunction. MATERIAL AND METHODS Patients with postoperative hyperbilirubinemia (those with conditions such as biliary complications and rejections were excluded) were randomly assigned, in a 2: 1 ratio, to the steroid and control groups. Patients in the steroid group were treated with glucocorticoid combined with ursodeoxycholic acid, whereas patients in the control group were only treated with ursodeoxycholic acid. The primary endpoint was decrease in bilirubin and the secondary endpoint was safety. RESULTS From 1st June 2016 to 30th April 2018, 40 patients were enrolled into the steroid group, and 20 were enrolled into the control group. Donor, recipient, and operative data were similar between the 2 groups. The decrease in bilirubin levels in the steroid group was significantly greater than that in the control group on the first day after the intervention was finished (9.25±1.30 mg/dL vs. 3.11±1.45 mg/dL, p=0.005), and after 2 weeks (15.01±1.20 mg/dL vs. 8.88±1.98 mg/dL, p=0.007). The steroid group did not have a higher complication rate but it did have a shorter postoperative hospital stay than in the control group. CONCLUSIONS Low-dose steroid therapy was effective and safe for treating hyperbilirubinemia caused by early graft dysfunction, and it improved liver function.

Donor Risk Index Has an Impact in Intraoperative Measure of Hepatic Artery Flow and in Clearance of Indocyanine Green: An Observational Cohort Study

BACKGROUND

The increase in indications for liver transplantation has led to acceptance of donors with expanded criteria. The donor risk index (DRI) was validated with the aim of being a predictive model of graft survival based on donor characteristics. Intraoperative arterial hepatic flow and indocyanine green clearance (plasma clearance rate of indocyanine green [ICG-PDR]) are easily measurable variables in the intraoperative period that may be influenced by graft quality. Our aim was to analyze the influence of DRI on intraoperative liver hemodynamic alterations and on intraoperative dynamic liver function testing (ICG-PDR).

METHODS

This investigation was an observational study of a single-center cohort (n = 228) with prospective data collection and retrospective data analysis. Measurement of intraoperative flow was made with a VeriQ flowmeter based on measurement of transit time (MFTT). The ICG-PDR was obtained from all patients with a LiMON monitor (Pulsion Medical Systems AG, Munich, Germany). DRI was calculated using a previously validated formula. Normally distributed variables were compared using Student's t test. Otherwise, the Mann-Whitney U test or Kruskal-Wallis test was applied, depending on whether there were 2 or more comparable groups. The qualitative variables and risk measurements were analyzed using the chi-square test. P < .05 was considered statistically significant.

RESULTS

DRI score (mean ± SD) was 1.58 ± 0.31. The group with DRI >1.7 (poor quality) had an intraoperative arterial flow of 234.2 ± 121.35 mL/min compared with the group having DRI < 1.7 (high quality), with an intraoperative arterial flow of 287.24 ± 156.84 mL/min (P = .02). The group with DRI >1.70 had an ICG-PDR of 14.75 ± 6.52%/min at 60 minutes after reperfusion compared to the group with DRI <1.70, with an ICG-PDR of 16.68 ± 6.47%/min at 60 minutes after reperfusion (P = .09).

CONCLUSION

Poor quality grafts have greater susceptibility to ischemia-reperfusion damage. Decreased intraoperative hepatic arterial flow may represent an increase in intrahepatic resistance early in the intraoperative period.

The Macrophage Activation Marker Soluble CD163 is Associated With Early Allograft Dysfunction After Liver Transplantation

BACKGROUND/OBJECTIVES

Soluble CD163 (sCD163), a macrophage activation marker, is upregulated in conditions of macrophage proliferation and activation. Elevated sCD163 levels have been associated with liver disease severity and progression. During liver transplantation, the implanted liver is exposed to ischaemia and reperfusion injury, resulting in an acute inflammatory response and macrophage activation. The relationship between sCD163 levels during liver transplantation and the development of early allograft dysfunction (EAD) has not been investigated.

METHODS

We included 27 cirrhosis patients (age 55 [range 32-72] years, 23 men) on the waiting list for liver transplantation. Alcohol consumption and viral hepatitis were the most frequent causes for cirrhosis. Patients were characterised by standard biochemical analysis and based on clinical disease severity scores. Information about donor, graft and course of the liver transplantation was recorded. sCD163 levels were measured at the time of liver transplantation before surgery, 2 h after reperfusion, and then at 24 h after transplantation.

RESULTS

We observed above-normal sCD163 levels at baseline (5.9 mg/L [4.7-8.8]). Two hours after reperfusion, sCD163 levels increased significantly from baseline (8.4 mg/L [7.4-10.9]; P < 0.01). Twenty-four hours after transplantation, sCD163 levels were significantly reduced compared with baseline (3.7 mg/L [2.9-5.5]; P < 0.01). However, in patients with EAD (n = 16), sCD163 levels were increased compared with patients without EAD (4.1 [3.2-7.4] vs. 3.1 [2.8-3.8] mg/L; P = 0.03).

CONCLUSIONS

We observed elevated sCD163 levels in patients with EAD after liver transplantation, confirming macrophage activation to play a role in EAD. Thus, sCD163 may be used as an early marker for EAD after liver transplantation, but larger studies are warranted to validate these findings.