The use of marginal grafts in liver transplantation

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

BACKGROUND & AIMS

The Banff Liver Working Group recently published consensus recommendations for steatosis assessment in donor liver biopsy, but few studies reported their use and no automated deep-learning algorithms based on the proposed criteria have been developed so far. We evaluated Banff recommendations on a large monocentric series of donor liver needle biopsies by comparing pathologists' scores with those generated by convolutional neural networks (CNNs) we specifically developed for automated steatosis assessment.

METHODS

We retrospectively retrieved 292 allograft liver needle biopsies collected between January 2016 and January 2020 and performed steatosis assessment using a former intra-institution method (pre-Banff method) and the newly introduced Banff recommendations. Scores provided by pathologists and CNN models were then compared, and the degree of agreement was measured with the intraclass correlation coefficient (ICC).

RESULTS

Regarding the pre-Banff method, poor agreement was observed between the pathologist and CNN models for small droplet macrovesicular steatosis (ICC: 0.38), large droplet macrovesicular steatosis (ICC: 0.08), and the final combined score (ICC: 0.16) evaluation, but none of these reached statistically significance. Interestingly, significantly improved agreement was observed using the Banff approach: ICC was 0.93 for the low-power score (p <0.001), 0.89 for the high-power score (p <0.001), and 0.93 for the final score (p <0.001). Comparing the pre-Banff method with the Banff approach on the same biopsy, pathologist and CNN model assessment showed a mean (±SD) percentage of discrepancy of 26.89 (±22.16) and 1.20 (±5.58), respectively.

CONCLUSIONS

Our findings support the use of Banff recommendations in daily practice and highlight the need for a granular analysis of their effect on liver transplantation outcomes.

IMPACT AND IMPLICATIONS

We developed and validated the first automated deep-learning algorithms for standardized steatosis assessment based on the Banff Liver Working Group consensus recommendations. Our algorithm provides an unbiased automated evaluation of steatosis, which will lay the groundwork for granular analysis of steatosis's short- and long-term effects on organ viability, enabling the identification of clinically relevant steatosis cut-offs for donor organ acceptance. Implementing our algorithm in daily clinical practice will allow for a more efficient and safe allocation of donor organs, improving the post-transplant outcomes of patients.

Utilization of hepatitis B surface antigen-positive donors in liver transplantation for recipients with hepatocellular carcinoma: a retrospective and propensity score matching analysis

Introduction

The use of extended criteria donor (ECD) grafts such as donor with infection of hepatitis B virus (HBV) is a potential solution for organ shortage. In this study, we aimed to evaluate the safety and long-term survival of utilization of hepatitis B surface antigen-positive (HBsAg+) donor livers in HCC patients using propensity score matching (PSM) analysis.

Methods

Forty-eight donors with HBsAg-positive and 279 donors with HBsAg-negative were transplanted and enrolled in this study. PSM analysis were used to eliminate selection bias. Perioperative data and survival were collected and analyzed.

Results

PSM generated 44 patient pairs. When comparing intra- and post-operative data, no significant difference was found between groups (P > 0.05). Patients with a HBsAg-positive donor had significantly worse progression-free survival (1-year: 65.9% vs. 90.9%; 3-year: 18.1% vs. 70.4%, P = 0.0060) and overall survival (1-year: 84.1% and 95.4%; 3-year: 27.2% vs. 79.5%, P = 0.0039). In multivariate analysis, donor HBsAg-positivity was an independent risk factor for survival and occurrence (P = 0.005 and 0.025, respectively).

Conclusion

In conclusion, with adequate antiviral prophylaxis and treatment, utilization of HBsAg positive liver grafts did not increase the incidence of early-stage complications. However, patient with an HBsAg-positive graft had poorer progression-free survival and overall survival.

Digital imaging software versus the "eyeball" method in quantifying steatosis in a liver biopsy

Steatotic livers represent a potentially underutilized resource to increase the donor graft pool; however, 1 barrier to the increased utilization of such grafts is the heterogeneity in the definition and the measurement of macrovesicular steatosis (MaS). Digital imaging software (DIS) may better standardize definitions to study posttransplant outcomes. Using HALO, a DIS, we analyzed 63 liver biopsies, from 3 transplant centers, transplanted between 2016 and 2018, and compared macrovesicular steatosis percentage (%MaS) as estimated by transplant center, donor hospital, and DIS. We also quantified the relationship between DIS characteristics and posttransplant outcomes using log-linear regression for peak aspartate aminotransferase, peak alanine aminotransferase, and total bilirubin on postoperative day 7, as well as logistic regression for early allograft dysfunction. Transplant centers and donor hospitals overestimated %MaS compared with DIS, with better agreement at lower %MaS and less agreement for higher %MaS. No DIS analyzed liver biopsies were calculated to be >20% %MaS; however, 40% of liver biopsies read by transplant center pathologists were read to be >30%. Percent MaS read by HALO was positively associated with peak aspartate aminotransferase (regression coefficient= 1.04 1.08 1.12 , p <0.001), peak alanine aminotransferase (regression coefficient = 1.04 1.08 1.12 , p <0.001), and early allograft dysfunction (OR= 1.10 1.40 1.78 , p =0.006). There was no association between HALO %MaS and total bilirubin on postoperative day 7 (regression coefficient = 0.99 1.01 1.04 , p =0.3). DIS provides reproducible quantification of steatosis that could standardize MaS definitions and identify phenotypes associated with good clinical outcomes to increase the utilization of steatite livers.

Is Liver Transplant Justified at Any MELD Score?

BACKGROUND

Assessing the survival benefit of transplantation in patients with end-stage liver disease is critical in guiding the decision-making process for liver allocation. Previous studies established increased mortality risk for those transplanted below Model for End-Stage Liver Disease (MELD) 18 compared with candidates who remained on the waitlist; however, improved outcomes of liver transplantation and a changing landscape in the donor supply warrant re-evaluation of this idea.

METHODS

Using the United Network for Organ Sharing database, we analyzed 160 290 candidates who were waitlisted for liver transplantation within MELD cohorts. We compared patients who were transplanted in a MELD cohort with those listed but not transplanted in that listed MELD cohort with an intent-to-treat analysis.

RESULTS

Those transplanted at a MELD between 6 and 11 showed a 31% reduction in adjusted mortality (HR = 0.69 [95% confidence interval [CI], 0.66-0.75]; P < 0.001) compared with the intent-to-treat cohort in a Cox multivariate regression. This mortality benefit increased to a 37% adjusted reduction for those transplanted at MELD between 12 and 14 (HR = 0.63 [95% CI, 0.60-0.66]; P < 0.001) and a 46% adjusted reduction for those transplanted at a MELD between 15 and 17 (HR = 0.54 [95% CI, 0.52-0.57]; P < 0.001), effects that remained in sensitivity analyses excluding patients with hepatocellular carcinoma, encephalopathy, ascites, and variceal bleeds. A multivariate analysis of patients transplanted at MELD < 18 found younger age and cold ischemia time were protective, whereas older age, lower functional status, and socioeconomic factors increased mortality risk.

CONCLUSIONS

These findings challenge the current practice of deferring liver transplants below a particular MELD score by demonstrating survival benefits for most transplant patients at the lowest MELD scores and providing insight into who benefits within these subgroups.

Long-term outcomes of liver transplantation using grafts from donors with active hepatitis B virus replication: a multicenter cohort study

Purpose

Liver grafts from donors with HBV infection contributed to expanding the donor pool under the hepatitis B immunoglobulin and antiviral agents (nucleos(t)ide analogues) in the HBV-endemic area. We report long-term outcomes of liver transplantations (LTs) using grafts from donors with active or chronic HBV infection.

Methods

Overall, 2,260 LTs performed in 3 major hospitals in Seoul from January 2000 to April 2019 were assessed for inclusion. Twenty-six grafts (1.2%) were obtained from HBsAg (+), HBeAb (+), or HBcAb (+) donors, and recipient outcomes were retrospectively reviewed. Donor and recipient demographics and transplantation outcomes were analyzed.

Results

Sixteen deceased donor LTs were performed using active HBsAg (+) grafts. Ten other LTs were sourced from 10 living donors. There was no significant difference in survival in patients who received deceased donor LTs compared with that in those who underwent LT with non-hepatitis virus-infected grafts. Fourteen patients who were followed up for >5 years were stable, and no difference in hepatocellular carcinoma recurrence rate was observed 5 years after transplantation between transplants from donors with and those without HBV.

Conclusion

Considering long-term outcomes, liver grafts from donors with active HBV replication can be safely used for LT.

Literature review of the mechanisms of acute kidney injury secondary to acute liver injury

People exposed to liver ischaemia reperfusion (IR) injury often develop acute kidney injury and the combination is associated with significant morbidity and mortality. Molecular mediators released by the liver in response to IR injury are the likely cause of acute kidney injury (AKI) in this setting, but the mediators have not yet been identified. Identifying the mechanism of injury will allow the identification of therapeutic targets which may modulate both liver IR injury and AKI following liver IR injury.

Comparison of results on the use of extended criteria liver doners for transplants in Espírito Santo

INTRODUCTION

liver Transplantation is currently the treatment of choice for several terminal liver diseases. Despite the increase in performed transplants, the waiting lists continue to increase. In order to expand the supply of organs, transplantation teams have started to use previously rejected livers for transplants because of an increased risk of unfavorable outcomes.

OBJECTIVE

to evaluate the use of livers of expanded criterion donators.

METHODS

retrospective study of medical records. The livers were classified as normal or expanded criteria. The groups were divided in low and high MELD. A multivariate analysis was performed through logistic regression.

RESULTS

there was no statistical difference regarding early, late and global mortality between the groups. Decreased survival was observed in patients with high MELD (higher or equal to 20) when they received grafts from expanded criterion donators. The association between the occurrence of cardiorespiratory arrest and presence of elevated total bilirubin in donators was associated with higher mortality rates in expanded criterion livers.

CONCLUSION

the overall results are similar, but expanded criteria liver donators was associated with higher mortality in patients with high MELD.

Clinical Implementation of Prolonged Liver Preservation and Monitoring Through Normothermic Machine Perfusion in Liver Transplantation

BACKGROUND

Normothermic machine perfusion (NMP) bears the potential for significant prolongation of liver preservation before transplantation. Although safety and feasibility have been recently published, no data are available describing the significant challenges of establishing NMP programs outside clinical studies. We herein present our experience and propose a multidisciplinary approach for liver NMP in the clinical routine.

METHODS

In February 2018, liver NMP was introduced for routine use in marginal organs, logistic challenges, and complex recipients at our institution. In a multidisciplinary effort among transplant coordinators, perfusionists, transplant surgeons, anesthesia, nurses, blood bank as well as laboratory staff, a clinical routine was established and 34 NMP cases were performed without critical incidents or organ loss.

RESULTS

Nine livers were discarded due to poor organ quality and function observed during NMP. Twenty-five livers were successfully transplanted after preservation of up to 38 h. The extended criteria donors rate was 100% and 92% in discarded and transplanted livers, respectively. Nighttime procedures and parallel transplantations were eventually omitted. Graft and patient survival was 88% at 20 mo. No cholangiopathy was observed despite the use of extended criteria donor organs in 92% of cases.

CONCLUSIONS

NMP in a multidisciplinary approach enables a safe prolongation of liver preservation and overnight organ care. A first field test of NMP indicates safety and benefit of this approach.

Outcomes After Declining a Steatotic Donor Liver for Liver Transplant Candidates in the United States

BACKGROUND

Steatotic donor livers (SDLs, ≥30% macrosteatosis on biopsy) are often declined, as they are associated with a higher risk of graft loss, even though candidates may wait an indefinite time for a subsequent organ offer. We sought to quantify outcomes for transplant candidates who declined or accepted an SDL offer.

METHODS

We used Scientific Registry of Transplant Recipients offer data from 2009 to 2015 to compare outcomes of 759 candidates who accepted an SDL to 13 362 matched controls who declined and followed candidates from the date of decision (decline or accept) until death or end of study period. We used a competing risk framework to understand the natural history of candidates who declined and Cox regression to compare postdecision survival after declining versus accepting (ie, what could have happened if candidates who declined had instead accepted).

RESULTS

Among those who declined an SDL, only 53.1% of candidates were subsequently transplanted, 23.8% died, and 19.4% were removed from the waitlist. Candidates who accepted had a brief perioperative risk period within the first month posttransplant (adjusted hazard ratio [aHR]: 2.493.494.89, P < 0.001), but a 62% lower mortality risk (aHR: 0.310.380.46, P < 0.001) beyond this. Although the long-term survival benefit of acceptance did not vary by candidate model for end-stage liver disease (MELD), the short-term risk period did. MELD 6-21 candidates who accepted an SDL had a 7.88-fold higher mortality risk (aHR: 4.807.8812.93, P < 0.001) in the first month posttransplant, whereas MELD 35-40 candidates had a 68% lower mortality risk (aHR: 0.110.320.90, P = 0.03).

CONCLUSIONS

Appropriately selected SDLs can decrease wait time and provide substantial long-term survival benefit for liver transplant candidates.

Minimizing Risks of Liver Transplantation With Steatotic Donor Livers by Preferred Recipient Matching

BACKGROUND

Donor livers with ≥30% macrosteatosis (steatotic livers) represent a possible expansion to the donor pool, but are frequently discarded as they are associated with an increased risk of mortality and graft loss. We hypothesized that there are certain recipient phenotypes that would tolerate donor steatosis well, and are therefore best suited to receive these grafts.

METHODS

Using national registry data from the Scientific Registry of Transplant Recipients between 2006 and 2017, we compared 2048 liver transplant recipients of steatotic livers with 69 394 recipients of nonsteatotic (<30%) livers. We identified recipient factors that amplified the impact of donor steatosis on mortality and graft loss using interaction analysis, classifying recipients without these factors as preferred recipients. We compared mortality and graft loss with steatotic versus nonsteatotic livers in preferred and nonpreferred recipients using Cox regression.

RESULTS

Preferred recipients of steatotic livers were determined to be first-time recipients with a model for end-stage liver disease 15-34, without primary biliary cirrhosis, and not on life support before transplant. Preferred recipients had no increased mortality risk (hazard ratio [HR]: 0.921.041.16; P = 0.5) or graft loss (HR: 0.931.031.15; P = 0.5) with steatotic versus nonsteatotic livers. Conversely, nonpreferred recipients had a 41% increased mortality risk (HR: 1.171.411.70; P < 0.001) and 39% increased risk of graft loss (HR: 1.161.391.66; P < 0.001) with steatotic versus nonsteatotic livers.

CONCLUSIONS

The risks of liver transplantation with steatotic donor livers could be minimized by appropriate recipient matching.

Temporal trends in utilization and outcomes of steatotic donor livers in the United States

Steatotic donor livers (SDLs) (macrosteatosis ≥30%) represent a possible donor pool expansion, but are frequently discarded due to a historical association with mortality and graft loss. However, changes in recipient/donor demographics, allocation policy, and clinical protocols might have altered utilization and outcomes of SDLs. We used Scientific Registry of Transplant Recipients data from 2005 to 2017 and adjusted multilevel regression to quantify temporal trends in discard rates (logistic) and posttransplant outcomes (Cox) of SDLs, accounting for Organ Procurement Organization-level variation. Of 4346 recovered SDLs, 58.0% were discarded in 2005, versus only 43.1% in 2017 (P < .001). SDLs were always substantially more likely discarded versus non-SDLs, although this difference decreased over time (adjusted odds ratio in 2005-2007:_13.15 15.28_17.74 ; 2008-2011:_11.77 13.41_15.29 ; 2012-2014:_9.87 11.37_13.10 ; 2015-2017:_7.79 8.89_10.15 , P < .001 for all). Conversely, posttransplant outcomes of recipients of SDLs improved over time: recipients of SDLs from 2012 to 2017 had 46% lower risk of mortality (adjusted hazard ratio [aHR]: _0.43 0.54_0.68 , P < .001) and 47% lower risk of graft loss (aHR: _0.42 0.53_0.67 , P < .001) compared to 2005 to 2011. In fact, in 2012 to 2017, recipients of SDLs had equivalent mortality (aHR: _0.90 1.04_1.21 , P = .6) and graft loss (aHR: _0.90 1.04_1.20 , P = .6) to recipients of non-SDLs. Increasing utilization of SDLs might be a reasonable strategy to expand the donor pool.

Systematic Review: Clinical Metabolomics to Forecast Outcomes in Liver Transplantation Surgery

Liver transplantation is an effective intervention for end-stage liver disease, fulminant hepatic failure, and early hepatocellular carcinoma. Yet, there is marked patient-to-patient variation in liver transplantation outcomes. This calls for novel diagnostics to enable rational deployment of donor livers. Metabolomics is a postgenomic high-throughput systems biology approach to diagnostic innovation in clinical medicine. We report here an original systematic review of the metabolomic studies that have identified putative biomarkers in the context of liver transplantation. Eighteen studies met the inclusion criteria that involved sampling of blood (n = 4), dialysate fluid (n = 4), bile (n = 5), and liver tissue (n = 5). Metabolites of amino acid and nitrogen metabolism, anaerobic glycolysis, lipid breakdown products, and bile acid metabolism were significantly different in transplanted livers with and without graft dysfunction. However, criteria for defining the graft dysfunction varied across studies. This systematic review demonstrates that metabolomics can be deployed in identification of metabolic indicators of graft dysfunction with a view to implicated molecular mechanisms. We conclude the article with a horizon scanning of metabolomics technology in liver transplantation and its future prospects and challenges in research and clinical practice.

Transplantation of HCV Viremic Livers into HCV Viremic Recipients Followed by Direct-acting Antiviral Therapy

Background and Aims: Hepatitis C virus (HCV)-infected organs are underutilized. We aimed to assess the safety and efficacy of direct-acting antiviral agents (DAAs) therapy in HCV viremic patients who are transplanted with a liver from a HCV viremic donor. Methods: We conducted a retrospective study, including patients seen from July 2015 to April 2017. HCV viremic patients transplanted with a liver from a HCV viremic donor and subsequently treated with DAAs were included. Outcomes assessed included undetectable viral load at 12 weeks after completing DAA therapy (sustained virologic response, SVR₁₂), adverse events, and interactions with immunosuppression. Results: Twenty-four HCV viremic recipients received livers from HCV viremic donors. Median age was 63 years, and the majority (79.2%) were genotype 1a. Donors and recipients were viremic at the time of transplant. Median modified model for end-stage liver disease score was 19, and median time on the waitlist was 81 days. Median time from transplant to initiation of DAA therapy was 123 days. Several DAA regimens were used and 15 (62.5%) patients did not receive ribavirin. Treatment duration ranged from 12 to 24 weeks. Twenty-three (95.8%) patients achieved SVR₁₂. Five (20.8%) patients developed adverse events; however, none required DAA discontinuation. Conclusions: DAA therapy was efficacious and well tolerated in HCV viremic recipients who underwent liver transplantation from a HCV viremic donor.

Systematic Review and Meta-Analysis on the Impact of Thrombolytic Therapy in Liver Transplantation Following Donation after Circulatory Death

Aim: The livers from DCD (donation after cardiac death) donations are often envisaged as a possible option to bridge the gap between the availability and increasing demand of organs for liver transplantation. However, DCD livers possess a heightened risk for complications and represent a formidable management challenge. The aim of this study was to evaluate the effects of thrombolytic flush in DCD liver transplantation. Methods: An extensive search of the literature database was made on MEDLINE, EMBASE, Cochrane, Crossref, Scopus databases, and clinical trial registry on 20 September 2018 to assess the role of thrombolytic tissue plasminogen activator (tPA) flush in DCD liver transplantation. Results: A total of four studies with 249 patients in the tPA group and 178 patients in the non-tPA group were included. The pooled data revealed a significant decrease in ischemic-type biliary lesions (ITBLs) (P = 0.04), re-transplantation rate (P = 0.0001), and no increased requirement of blood transfusion (P = 0.16) with a better one year graft survival (P = 0.02). Conclusions: To recapitulate, tPA in DCD liver transplantation decreased the incidence of ITBLs, re-transplantation and markedly improved 1-year graft survival, without any increased risk for blood transfusion, hence it has potential to expand the boundaries of DCD liver transplantation.

Computational Modeling of Oxidative Stress in Fatty Livers Elucidates the Underlying Mechanism of the Increased Susceptibility to Ischemia/Reperfusion Injury

QUESTION

Donor liver organs with moderate to high fat content (i.e. steatosis) suffer from an enhanced susceptibility to ischemia/reperfusion injury (IRI) during liver transplantation. Responsible for the cellular injury is an increased level of oxidative stress, however the underlying mechanistic network is still not fully understood.

METHOD

We developed a phenomenological mathematical model of key processes of hepatic lipid metabolism linked to pathways of oxidative stress. The model allows the simulation of hypoxia (i.e. ischemia-like conditions) and reoxygenation (i.e. reperfusion-like conditions) for various degrees of steatosis and predicts the level of hepatic lipid peroxidation (LPO) as a marker of cell damage caused by oxidative stress.

RESULTS & CONCLUSIONS

Our modeling results show that the underlying feedback loop between the formation of reactive oxygen species (ROS) and LPO leads to bistable systems behavior. Here, the first stable state corresponds to a low basal level of ROS production. The system is directed to this state for healthy, non-steatotic livers. The second stable state corresponds to a high level of oxidative stress with an enhanced formation of ROS and LPO. This state is reached, if steatotic livers with a high fat content undergo a hypoxic phase. Theoretically, our proposed mechanistic network would support the prediction of the maximal tolerable ischemia time for steatotic livers: Exceeding this limit during the transplantation process would lead to severe IRI and a considerable increased risk for liver failure.

Use of Hepatitis C-Positive Donor Livers in Liver Transplantation

PURPOSE OF REVIEW

The purpose of this article is to review recent literature regarding the use of Hepatitis C virus (HCV) positive donor livers in liver transplantation. Given the prevalence of HCV-positive patients on the waitlist coupled with high waitlist mortality, use of HCV-positive livers may be a means to meet patient needs. This review seeks to primarily answer the following questions: can HCV-positive livers be used safely and effectively? Are new direct acting antiviral medications safe and effective in HCV-positive liver recipients?

RECENT FINDINGS

Use of HCV-positive donor livers for liver transplantation in HCV-positive recipients is increasing. These donor livers have equivalent patient and graft survival when compared to HCV-negative donor livers in HCV-positive liver transplant recipients. Recent studies suggest that use of direct acting antiviral medications in HCV-positive liver transplant recipients can be successful, although there is insufficient data for their use in recipients of HCV-positive donor livers.

SUMMARY

HCV-positive donor livers may be safely and effectively used in HCV-positive liver transplant recipients. Direct acting antiviral medications appear safe and effective in HCV-positive liver transplant recipients, but data on their efficacy in HCV-positive liver transplant recipients are limited. Future research should focus on the use of HCV-positive donor livers in HCV-negative liver transplant recipients.

Split liver transplantation using Hemiliver graft in the MELD era: a single center experience in the United States

Under the "sickest first" Model for End-Stage Liver Disease (MELD) allocation, livers amenable to splitting are most often allocated to patients unsuitable for split liver transplantation (SLT). Our experience with SLT using hemilivers was reviewed. From April 2004 to June 2012, we used 25 lobar grafts (10 left lobes and 15 right lobes) for adult-sized recipients. Twelve recipients were transplanted with primary offers, and 13 were transplanted with leftover grafts. Six grafts were shared with other centers. The data were compared with matched whole liver grafts (n = 121). In 92% of donors, the livers were split in situ. Hemiliver recipients with severe portal hypertension had a greater graft-to-recipient weight ratio than those without severe portal hypertension (1.96% vs. 1.40%, p < 0.05). Hemiliver recipients experienced biliary complications more frequently (32.0% vs. 10.7%, p = 0.01); however, the 5-year graft survival for hemilivers was comparable to whole livers (80.0% vs. 81.5%, p = 0.43). The secondary recipients with leftover grafts did not have increased incidences of graft failure (p = 0.99) or surgical complications (p = 0.43) compared to the primary recipients. In conclusion, while routine application is still controversial due to various challenges, hemiliver SLT can achieve excellent outcomes under the MELD allocation.

Changing donor characteristics in liver transplantation over the last 10 years in Canada

Liver donor characteristics have a significant impact on graft quality and, in turn, recipient outcomes. In this study, we examined deceased liver donor characteristics and donor risk index (DRI) trends in Canada over the past decade. Data were extracted from the Canadian Organ Replacement Register and Transplant Québec for the decade (2000-2010). Trends in the DRI and donor characteristics, including age, race, height, cause of death (COD), location, cold ischemia time (CIT), and type of donation, were examined. In all, 3746 transplants using deceased liver donors were analyzed. The age of donors, the proportion of black donors, the proportion of cerebrovascular accidents as the COD, and the proportion of donation after cardiac death (DCD) donors all increased over the aforementioned time period. The proportion of transplants classified geographically as local increased, and the CIT for donor livers decreased. Although many of the parameters adversely affecting the DRI increased over the study period, the DRI showed only a slightly significant trend of increasing. The increase in these parameters was counteracted by a decrease in modifiable risk factors such as the CIT and distance traveled. The 5-year recipient survival rate increased from 71.43% (1999-2001) to 75.50% (2005-2007); however, this trend was not significant. Although there was an increase in the use of older and DCD organs, recipient survival was not compromised. In conclusion, demographic trends for liver donors in Canada suggest an increase in the use of higher risk donors. However, the overall graft quality has been not compromised because of a decreasing trend for the CIT and an increase in local transplants. Better coordination and allocation practices in liver transplantation across Canada have minimized the risk of graft failure and resulted in good recipient outcomes.

Suramin decreases injury and improves regeneration of ethanol-induced steatotic partial liver grafts

Steatotic grafts are excluded for use in partial liver transplantation (LT) because of the increased risk of primary nonfunction. This study investigated the effects of suramin, a polysulfonated naphthylurea, on the outcome of steatotic partial LT. Rat livers were harvested after acute ethanol treatment (6 g/kg, intragastric administration), reduced in size to ≈ 1/3, and transplanted. Serum alanine aminotransferase (ALT) and total bilirubin levels as well as hepatic necrosis and apoptosis were significantly higher after transplantation of fatty partial grafts (FPG) than lean partial grafts (LPG). Suramin (5 mg/kg, i.p.) decreased ALT by ≈ 60%, hyperbilirubinemia by 75%, necrosis by 83%, and apoptosis by 70% after FPG transplantation. Hepatic cellular 5-bromo-2'-deoxyuridine (BrdU) incorporation increased to 28% in LPG but was only 2% in FPG at 48 hours, and the mitotic index increased to 7% in LPG but was only 0.2% in FPG, indicating suppressed regeneration in FPG. Suramin increased BrdU incorporation and the mitotic index to 43% and 9%, respectively, in FPG. All FPG recipients died within 5 days. Suramin recovered survival of FPG to 62%. Tumor necrosis factor-α (TNF-α) mRNA was 2.2-fold higher in FPG than in LPG and was associated with activation of caspase-8 and caspase-3 in FPG. Suramin decreased TNF-α and caspase activation in FPG. Transforming growth factor-β (TGF-β), phospho-Smad2/3 and p21Cip1 were significantly higher in FPG than in LPG and suramin blocked TGF-β formation and its down-stream signaling pathway. Taken together, suramin improves the outcome of FPG transplantation, most likely by inhibition of TNF-α and TGF-β formation.

Multi-excitation fluorescence spectroscopy for analysis of non-alcoholic fatty liver disease

BACKGROUND AND OBJECTIVES

The increasing incidence of non-alcoholic fatty liver diseases (NAFLD) and the consequent progression to cirrhosis is expected to become a major cause of liver transplantation. This will exacerbate the organ donor shortage and mean that 'marginal' fatty liver grafts are more frequently used. Autofluorescence spectroscopy is a fast, objective, and non-destructive method to detect change in the endogenous fluorophores distribution and could prove to be a valuable tool for NAFLD diagnosis and transplant graft assessment.

MATERIALS AND METHODS

A system was constructed consisting of a fibre probe with two laser diodes that provided excitation light at 375 and 405 nm, and an imaging spectrograph system. This was used to distinguish fluorescence spectra acquired from the harvested livers from mice with NAFLD of differing severity (healthy, mild steatotic and steatohepatitic). The fluorescence data were entered into a sparse multiclass probabilistic algorithm for disease classification. Histopathology, thiobarbituric acid reactive substances (TBARS) and alanine transaminase (ALT) assays were conducted in addition to the fluorescence measurements

RESULTS

TBARS and ALT assays enabled differentiation of the steatohepatitic group from the mild steatosis and control groups (P ≤ 0.028) but failed to separate the mild steatotic group from the control group. The three groups were all clearly differentiated from each other using fluorescence spectroscopy, and classification accuracy was found to be 95%.

CONCLUSION

Fluorescence spectroscopy appears to be a promising approach for the analysis of diseased liver tissue.

Incidence and predictors of post-reperfusion syndrome in living donor liver transplantation

A characteristic pattern of hemodynamic changes that may occur in reperfusion phase of liver transplantation (LT) is known as post-reperfusion syndrome (PRS). In this study, we determined the frequency of PRS and evaluated possible predictors of PRS. The medical records of 152 patients who underwent living donor LT were reviewed. PRS was defined as a decrease in mean arterial pressure of more than 30% from the baseline value for more than one min during the first five min after reperfusion. The frequency of PRS was determined, and patients were divided into two groups: PRS group and non-PRS group. Donor factors, preoperative and intraoperative recipient factors, and postoperative outcomes were compared between the two groups. PRS occurred in 58 recipients (34.2%). Preoperative model for end-stage liver disease scores of recipients and percentage of graft steatotic changes were higher in PRS group. PRS group showed higher heart rates and lower hemoglobin values preoperatively. Before reperfusion, PRS group received more transfusion and their urine output was less than that of non-PRS group. Postoperatively, peak bilirubin during the first five d after LT was higher in PRS group. In conclusion, both severity of liver disease and graft steatosis may increase risk for PRS in LT. Further prospective studies of PRS in its relationship to outcome are indicated.

Schistosoma mansoni infection in the liver graft: The impact on donor and recipient outcomes after transplantation

The increasing number of transplants performed each year has led to the identification of unusual diseases in liver grafts from asymptomatic donors that were unrecognized before liver transplantation. Here we report our experience with patients who received liver grafts infected with schistosomiasis. From September 1991 to August 2010, 482 pediatric liver transplants were performed at A. C. Camargo Hospital/Sírio-Libanês Hospital (São Paulo, Brazil). For the identification of Schistosoma mansoni infections, pathology slides for the recipients were reviewed; these included postreperfusion and follow-up liver biopsy samples. We were able to identify 6 cases of schistosomiasis transmitted through infected grafts (5 of these grafts were from living donors). All living donors were confirmed to have normal liver chemistries, negative fecal tests for parasitic diseases, and normal abdominal ultrasound findings. Liver biopsy was not performed before transplantation. In all cases, features of schistosomiasis were absent in the liver explants. The living donors were treated with praziquantel and were taught to avoid risk factors for reinfection. No specific treatment for schistosomiasis was given to the recipients. There were no perioperative deaths, but 2 recipients died after living donor liver transplantation (LDLT) because of Kaposi's sarcoma and non-Hodgkin's lymphoma. In conclusion, using liver grafts infected with S. mansoni eggs did not compromise the results of LDLT in this pediatric cohort. Because of the parasite's life cycle and the therapeutic target of praziquantel, only donors should be treated for the infection. Three years of follow-up showed an uneventful recovery for the living donors.

Ischemic cholangiopathy after controlled donation after cardiac death liver transplantation: a meta-analysis

OBJECTIVE

To conduct a meta-analysis to enhance understanding of the risks of biliary complications, particularly ischemic cholangiopathy (IC), after donation after cardiac death (DCD) compared with donation after brain death (DBD) liver transplantation.

BACKGROUND

Biliary complications after liver transplantation have profound health and economic implications which merit further investigation.

METHODS

The MEDLINE (1950–2009), EMBASE, and Cochrane Library databases were searched and supplemented by review of conference proceedings and publication bibliographies. All original single institution studies reporting outcomes for DCD and DBD liver transplant recipients were considered. Odds ratios (OR) and 95% confidence intervals (CI) based on random effects models were calculated.

RESULTS

Eleven publications, all retrospective cohort studies, involving 489 DCD and 4455 DBD recipients, were included. Donation after cardiac death recipients had a 2.4 times increased odds of biliary complications (95% CI= 1.8–3.4) and a 10.8 times increased odds of IC (95% CI = 4.8–24.2).Ischemic cholangiopathy was present in 16% of DCD compared with 3% of DBD recipients. Donation after cardiac death recipients also experienced higher odds of 1-year patient mortality (OR = 1.6, 95% CI = 1.04–2.5) and graft failure (OR = 2.1, 95% CI = 1.5–2.8).

CONCLUSIONS

Donation after cardiac death liver transplantation is marred by inferior outcomes including higher rates of biliary complications and IC as well as increased mortality and graft failure. Despite current federal mandates to increase DCD donation, these serious complications translate into poor outcomes for individuals and increased healthcare costs. These risks should be considered in decisions regarding the utilization of these grafts.

Use of a third-generation perfluorocarbon for preservation of rat DCD liver grafts

BACKGROUND

Cold storage in any of the commonly used preservation solutions is not always adequate for donation after cardiac death (DCD) liver grafts due to prolonged warm ischemic time. In this study, we used a third-generation perfluorocarbon (PFC), Oxycyte, for DCD liver graft preservation in a rat model.

MATERIALS AND METHODS

Twenty-eight rats (14 in each group) were used. Thirty minutes after cardiopulmonary arrest, livers were harvested and flushed with a cold and pre-oxygenated solution of either University of Wisconsin (UW) or UW + 20% PFC. After 8 h of cold preservation in either of the investigated solutions, liver graft specimens were analyzed for evidence of ischemic injury. Hemotoxylin and eosin staining (H and E), as well as immunohistochemical analysis with anti-cleaved caspase 3 antibody, was performed. Levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the preservation solution were analyzed at 1 and 8 h during preservation.

RESULTS

In the PFC group, the degree of cell congestion, vacuolization and necrosis were all significantly less than in the UW group (P = 0.002-0.004). The number of cells with a positive cleaved caspase 3 antibody reaction was reduced by about 50% in comparison with the UW group (P < 0.006). The AST level in the PFC group was significantly less than in the UW group after 8 h of preservation (P < 0.048).

CONCLUSION

The addition of PFC to UW solution significantly decreases the degree of histologic damage in rat DCD liver grafts. This preservation strategy can be potentially helpful for organ preservation after prolonged warm ischemia.

Liver allografts from hepatitis C positive donors can offer good outcomes in hepatitis C positive recipients: a US National Transplant Registry analysis

Organ donors are screened for the hepatitis C antibody (anti-HCV) and those with positive tests can be used under extended criteria donation. However, there is still a question of long-term organ viability. The aim of this study was to assess the long-term outcomes of anti-HCV positive (HCV+) liver grafts. The US Organ Procurement and Transplantation Network Scientific Registry was reviewed for the period from April 1994 to February 6, 2008 and 56,275 liver transplantations were analyzed. In total, there were 19,496 HCV+ recipients and 934 HCV+ donors. Patient and graft survival were assessed accounting for both donor and recipient anti-HCV status. Multivariable proportional hazards survival models were developed to adjust for factors known to affect post-transplant survival. With anti-HCV negative (HCV-) recipient/HCV- donor as the reference, the adjusted hazard ratio for death was similar for HCV+ recipient/HCV- donor compared with HCV+ recipient/HCV+ donor (1.176 vs. 1.165, P = 0.91). Our results suggest that HCV+ liver donors do not subject the HCV+ recipient to an increased risk for death over the HCV- donor, keeping in mind that careful donor and recipient selection is critical for the proper use of these extended criteria donors.

Use of tissue plasminogen activator in liver transplantation from donation after cardiac death donors

Ischemic-type biliary stricture (ITBS) occurs in up to 50% after liver transplantation (LT) from donation after cardiac death (DCD) donors. Thrombus formation in the peribiliary microcirculation is a postulated mechanism. The aim was to describe our experience of tissue plasminogen activator (TPA) administration in DCD-LT. TPA was injected into the donor hepatic artery on the backtable (n = 22). Two recipients developed ITBS including one graft failure. Although excessive postreperfusion bleeding was seen in 14 recipients, the amount of TPA was comparable between those with and without excessive bleeding (6.4 ± 2.8 vs. 6.6 ± 2.8 mg, p = 0.78). However, donor age (41 ± 12 vs. 29 ± 9 years, p = 0.02), donor BMI (26.3 ± 5.5 vs. 21.7 ± 3.6 kg/m(2) , p = 0.03), previous laparotomy (50% vs. 0%, p = 0.02) and lactate after portal reperfusion (6.3 ± 4.6 vs. 2.8 ± 0.9 mmol/L, p = 0.005) were significantly greater in recipients with excessive bleeding. In conclusion, the use of TPA may lower the risk of ITBS-related graft failure in DCD-LT. Excessive bleeding may be related to poor graft quality and previous laparotomy rather than the amount of TPA. Further studies are needed in larger population.

Identification of new donor variables associated with graft survival in a single-center liver transplant cohort

We currently face the more widespread use of marginal livers for organ transplantation. Therefore, it is imperative to adequately identify the factors affecting early and late graft survival in that setting. The objective of this study was to determine the donor variables associated with graft survival in the liver transplant program of the University of Montreal. We retrospectively studied the survival of 634 grafts transplanted into 634 recipients between 1990 and 2008. The variables associated with 1- and 5-year graft survival were identified with the Cox proportional hazards regression model. The donor population was characterized by a mean age of 45.24 ± 18.15 years; 52.8% had at least 1 of the currently recognized extended criteria donor factors. The recipients had a mean age of 52.51 ± 10.80 years and a mean Child-Pugh score of 9.58 ± 2.32. Liver grafts were considered inadequate with respect to their gross appearance in 16 cases (2.5%). The 1- and 5-year graft survival rates were 78.7% and 71.1%, respectively. According to a Cox regression multivariate analysis, the independent determining factors associated with graft survival were (1) the graft appearance (P < 0.001 at 1 and 5 years), (2) the donor partial pressure of oxygen/fraction of inspired oxygen ratio (P = 0.005 at 1 year and P < 0.005 at 5 years), and (3) the donor hemoglobin level (P = 0.008 at 1 year and P = 0.005 at 5 years). In conclusion, the gross graft appearance, the presence of donor lung diffusion abnormalities, and the donor hemoglobin levels were significantly associated with graft survival. These observations, if they are confirmed, could improve our ability to select marginal organs.

Inhibition of inducible nitric oxide synthase prevents mitochondrial damage and improves survival of steatotic partial liver grafts

BACKGROUND

Steatotic liver grafts are excluded for partial liver transplantation because of increased risk of primary nonfunction. Mechanisms underlying the failure of fatty partial liver grafts (FPG) remain unknown. This study investigated whether inducible nitric oxide synthase (iNOS) plays a role in failure of FPG.

METHODS

Fatty livers were induced by feeding rats a high-fat high-fructose diet for 2 weeks. Hepatic triglyceride was approximately 9-fold higher in rats fed the high-fat high-fructose diet than those fed a low-fat low-fructose diet. Lean and fatty liver explants were reduced in size ex vivo to approximately one third, stored in the University of Wisconsin cold storage solution for 2 hr, and implanted.

RESULTS

Posttransplantational hepatic iNOS expression and reactive nitrogen species (RNS) formation (nitrite and nitrate levels and 3-nitrotyrosine adducts) increased more profoundly in FPG than in lean partial grafts (LPG). Serum alanine aminotransferase and bilirubin were 2- and 5.5-fold higher after transplantation of FPG than LPG. 5-Bromo-2'-deoxyuridine incorporation was 25% in LPG but only 5% in FPG, and graft weight increased by 64% in LPG while remaining unchanged in FPG. All rats that received FPG died, whereas all those receiving LPG survived. N-(1-naphtyl)ethylendiamine dihydrochloride (5 microM), a specific iNOS inhibitor, largely blunted the production of RNS, prevented the increase of alanine aminotransferase and bilirubin, restored liver regeneration, and improved survival of FPG. Mitochondrial cytochrome c oxidase-IV, ATP synthase-beta, and NADH dehydrogenase-3 decreased markedly in FPG, and these effects were blocked by N-(1-naphtyl)ethylendiamine dihydrochloride.

CONCLUSION

Thus, hepatic steatosis causes failure of partial liver grafts, most likely by increasing RNS that leads to mitochondrial damage and dysfunction.

Early diagnosis of primary nonfunction and indication for reoperation after liver transplantation

Initial graft function is a major factor influencing the clinical outcome after liver transplantation (LTX), but a reliable method for assessing and predicting graft dysfunction directly after LTX is not available. Ninety-nine patients undergoing deceased-donor LTX were studied in a prospective pilot study to evaluate the LiMAx test, the indocyanine green test, and conventional biochemical parameters with respect to their sensitivity and prognostic power for the diagnosis of initial graft dysfunction. Patients suffering from initial graft dysfunction (defined as technical complications or primary nonfunction (n = 8)) had significantly decreased LiMAx readouts (43 +/- 18 versus 184 +/- 98 mug/kg/hour, P < 0.001) immediately after LTX. Univariate analysis also showed significant differences for serum bilirubin, ammonia, glutamate dehydrogenase, and the international normalized ratio (P < 0.05), but multivariate analysis revealed LiMAx as the single independent predictor of initial dysfunction (P = 0.008) with an area under the receiver operating characteristic curve (AUROC) of 0.960 (95% confidence interval = 0.921-0.998, P < 0.001). In addition, the diagnosis of primary nonfunction (n = 3) was evaluated with LiMAx and aspartate aminotransferase (AST) activity on the first postoperative day. The calculated AUROC values were 0.992 (0.975-1.0, P = 0.004) for LiMAx and 0.967 (0.929-1.0, P = 0.006) for AST. By a combination of test results obtained directly after LTX and on the first day, LiMAx indicated primary nonfunction with a sensitivity of 1.0 (0.31-1.0) and a positive predictive value of 1.0 (0.31-1.0), whereas AST classification showed a sensitivity of 0.67 (0.13-0.98) and a positive predictive value of 0.29 (0.05-0.70). In conclusion, the assessment of initial graft function using the LiMAx test might be effective for identifying critical complications that could threaten graft survival within 24 hours after LTX.

Traumatized Liver Grafts for Organ Donation? A Single-Center Experience

Because the number of patients on waiting lists increases each year, new strategies are urgently needed to expand the donor pool. The use of traumatized donor livers for orthotopic liver transplantation at a transplant center is described. After transplantation, no increased incidence of perioperative complications such as bleeding, bile leakage, or liver graft dysfunction were observed and the transplanted livers exhibited appropriate long-term function. Thus, the use of injured livers may offer new opportunities in transplantation.

Donor transmission of malignant melanoma to a liver graft recipient: case report and literature review

Post-transplant malignancy of donor origin is a rare complication of organ transplantation, most likely transmitted as micrometastases within the parenchyma of the donor organ or from circulating tumor cells contained within the organ. Patient survival is dependent upon early diagnoses, and differentiation of the malignancy as of donor or recipient derivation is important in developing a treatment modality. The utilization of fluorescent in situ hybridization chromosome analysis and DNA sequence analysis of the tumor cells can assist in this determination. This case report describes the management of donor transmitted malignant melanoma in a liver graft recipient and a review of the current literature.

Expanding the Donor Pool for Liver Transplantation in the Setting of an “Opt-out” Scheme – 3 years after New Legislation

Introduction: The revised Human Organ Transplant Act (HOTA) was implemented in Singapore in July 2004. We aim to evaluate expanding the potential donor pool for liver transplant in Singapore with the inclusion of marginal donors. Materials and Methods: All donor referrals between July 2004 and June 2007 were studied. All potential deceased liver donors were heart-beating. After being reviewed by the transplant coordinator, potential donors were assessed by a transplant hepatologist and a transplant surgeon for suitability of organ donation strictly based on the programme’s donor assessment protocol. Reasons for rejection as potential donors were documented. The clinical characteristics of all donor referrals were retrospectively reviewed, and an independent decision was made as to whether liver retrieval in each rejected case might have been possible. Results: Among the 128 potential donor referrals, 20 donors (15.6%) underwent liver retrieval. Of the 20 livers retrieved, 16 were implanted and 4 were not implanted (3 unfit recipients, and 1 donor liver with 40% steatosis). Another 10 donor livers were assessed intraoperatively and were rejected because of varying levels of steatosis. Of these livers assessed, 5 donor livers had steatosis <40% and 5 had steatosis >40%. Of the remaining potential donors, 45 were deemed not possible because of prolonged hypotension (9), on-going or unresolved sepsis (13), high-risk behaviour (4), non-actualisation (8), or pre-existing medical conditions (11). Another 53 donors may potentially have been suitable donors but were rejected because of possible sepsis (13), no suitable recipients (12), transient hypotension (10), transient abnormal liver function test (6), history of alcohol ingestion (5), non-actualisation because of consent (4) and other reasons (3). Overall, it was deemed that 61 donors (47.7%) might potentially have been suitable liver donors. Conclusions: Despite new legislation (HOTA) in Singapore, the utilisation of cadaveric donor livers showed no increase in the last 3 years. By expanding our donor criteria to include marginal donors, we could potentially increase the availability of deceased donor livers to meet our waiting list demands. Key words: Liver transplant, Marginal livers, New legislation, Opt-out scheme