How can we utilize livers from advanced aged donors for liver transplantation for hepatitis C?

Asian Pacific Association for the Study of the Liver clinical practice guidelines on liver transplantation

Liver transplantation is a highly complex and challenging field of clinical practice. Although it was originally developed in western countries, it has been further advanced in Asian countries through the use of living donor liver transplantation. This method of transplantation is the only available option in many countries in the Asia-Pacific region due to the lack of deceased organ donation. As a result of this clinical situation, there is a growing need for guidelines that are specific to the Asia-Pacific region. These guidelines provide comprehensive recommendations for evidence-based management throughout the entire process of liver transplantation, covering both deceased and living donor liver transplantation. In addition, the development of these guidelines has been a collaborative effort between medical professionals from various countries in the region. This has allowed for the inclusion of diverse perspectives and experiences, leading to a more comprehensive and effective set of guidelines.

Prognostic role of the Donor Risk Index, the Eurotransplant Donor Risk Index, and the Balance of Risk score on graft loss after liver transplantation

This study aimed to identify cutoff values for donor risk index (DRI), Eurotransplant (ET)-DRI, and balance of risk (BAR) scores that predict the risk of liver graft loss. MEDLINE and Web of Science databases were searched systematically and unrestrictedly. Graft loss odds ratios and 95% confidence intervals were assessed by meta-analyses using Mantel-Haenszel tests with a random-effects model. Cutoff values for predicting graft loss at 3 months, 1 year, and 3 years were analyzed for each of the scores. Measures of calibration and discrimination used in studies validating the DRI and the ET-DRI were summarized. DRI ≥ 1.4 (six studies, n = 35 580 patients) and ET-DRI ≥ 1.4 (four studies, n = 11 666 patients) were associated with the highest risk of graft loss at all time points. BAR > 18 was associated with the highest risk of 3-month and 1-year graft loss (n = 6499 patients). A DRI cutoff of 1.8 and an ET-DRI cutoff of 1.7 were estimated using a summary receiver operator characteristic curve, but the sensitivity and specificity of these cutoff values were low. A DRI and ET-DRI score ≥ 1.4 and a BAR score > 18 have a negative influence on graft survival, but these cutoff values are not well suited for predicting graft loss.

Ex vivo machine perfusion: current applications and future directions in liver transplantation

BACKGROUND

Liver transplantation is the only curative treatment option for end-stage liver disease; however, its use remains limited due to a shortage of suitable organs. In recent years, ex vivo liver machine perfusion has been introduced to liver transplantation, as a means to expand the donor organ pool.

PURPOSE

To present a systematic review of prospective clinical studies on ex vivo liver machine perfusion, in order to assess current applications and highlight future directions.

METHODS

A systematic literature search of both PubMed and ISI web of science databases as well as the ClinicalTrials.gov registry was performed.

RESULTS

Twenty-one articles on prospective clinical trials on ex vivo liver machine perfusion were identified. Out of these, eight reported on hypothermic, eleven on normothermic, and two on sequential perfusion. These trials have demonstrated the safety and feasibility of ex vivo liver machine perfusion in both standard and expanded criteria donors. Currently, there are twelve studies enrolled in the clinicaltrials.gov  registry, and these focus on use of ex vivo perfusion in extended criteria donors and declined organs.

CONCLUSION

Ex vivo liver machine perfusion seems to be a suitable strategy to expand the donor pool for liver transplantation and holds promise as a platform for reconditioning diseased organs.

The Graz Liver Allocation Strategy-Impact of Extended Criteria Grafts on Outcome Considering Immunological Aspects

Background: Transplant centers are forced to use livers of extended criteria donors for transplantation due to a dramatic organ shortage. The outcome effect of extended donor criteria (EDCs) remains unclear. Thus, this study was designed to assess the impact of EDCs on outcome including immunological aspects after liver transplantation (LT). Patients and Methods: Between November 2016 and March 2018, 49 patients (85.7% male) with a mean age of 57 ± 11 years underwent LT. The impact of EDCs on outcome after LT was assessed retrospectively using both MedOcs and ENIS (Eurotransplant Network Information System). Results: About 80% of grafts derived from extended criteria donors. Alanine aminotransferase/aspartate aminotransferase (AST/ALT) levels elevated more than three times above normal values in organ donors was the only significant risk factor for primary dysfunction (PDF) and primary non-function (PNF)/Re-LT and early non-anastomotic biliary strictures (NAS). Balance of risk (BAR) score did not differ between EDC and non-EDC recipients. PDF (14.3% of all patients) and PNF (6.1% of all patients) occurred in 23.1% of EDC-graft recipients and in 10.0% of non-EDC-graft recipients (RR 2.31, p = 0.663). The 90-day mortality was 3.6%. There was no difference of early non-anastomotic biliary tract complications and biopsy proven rejections (BPR). There was no correlation of PDF/PNF with BPR and NAS, respectively; however, 66.7% of the patients with BPR also developed early NAS (p < 0.001). Conclusion: With the Graz liver allocation strategy, excellent survival can be achieved selecting livers with no more than 2 not outcome-relevant EDCs for patients with MELD >20. Further, BPR is associated with biliary complications.

The Impact of Share 35 Policy on Patient Survival in Patients Undergoing Liver Transplantation With Gender- and Race-Mismatched Donors: An Analysis of the United Network for Organ Sharing Registry

INTRODUCTION

The United Network for Organ Sharing (UNOS) instituted the Share 35 policy in June 2013 in order to reduce death on liver transplant waitlist. The effect of this policy on patient survival among patients with gender- and race-mismatched donors has not been examined.

RESEARCH QUESTION

To assess the impact of Share 35 policy on posttransplantation patient survival among patients with end-stage liver disease (ESLD) transplanted with gender- and race-mismatched donors.

DESIGN

A total of 16 467 adult patients with ESLD who underwent liver transplantation between 2012 and 2015 were identified from UNOS. An overall Cox proportional hazards model adjusting for demographic, clinical, and geographic factors and separate models with a dummy variable of pre- and post-Share 35 periods as well as its interaction with other factors were performed to model the effect of gender and race mismatch on posttransplantation patient survival and to compare the patient survival differences between the first 18 months of Share 35 policy to an equivalent time period before.

RESULTS

Comparison of the pre- and post-Share 35 periods did not show significant changes in the numbers of gender- and race-mismatched transplants, or the risk of death for gender-mismatched recipients. However, black recipients with Hispanic donors (hazard ratio: 0.51, 95% confidence interval, 0.29-0.90) had significantly increased patient survival after Share 35 policy took effect.

CONCLUSION

The Share 35 policy had a moderate impact on posttransplantation patient survival among recipients with racially mismatched donors according to the first 18-month experience. Future research is recommended to explore long-term transplantation.

Transplant for the very sick: No limitations in donor quality?

When it comes to maximizing allograft function, the recipient is just as important as the liver graft itself. Whereas the “healthiest” of liver transplant candidates are likely to gain significant benefit from a liver graft of any quality, the sickest of candidates may still die despite transplantation with even an ideal liver. However, the very sick patients are precisely the ones who have the greatest need for liver transplantation—with any liver, regardless of quality—because they are most vulnerable to pretransplant death without one. How does one balance the urgent need for liver transplantation with optimization of the allograft’s function and utility for the very sick patient?

Extended Criteria Donors in Liver Transplantation

Mortality rates on the liver transplant waiting list are increasing. The shortage of organs has resulted in higher utilization of extended criteria donors (ECDs), with centers pushing the limits of what is acceptable for transplantation. Donor quality is more appropriately represented as a continuum of risk, and careful selection and matching of ECD grafts with recipients may lead to excellent outcomes. Although there is no precise definition for what constitutes an ECD liver, this review focuses on frequently cited characteristics, including donor age, steatosis, donation after cardiac death, and donors with increased risk of disease transmission.

The use of old donors in liver transplantation

The process of ageing has an impact on the entire human body including the organ systems. In transplantation, professionals are daily faced with risk assessment of suitable donor offers , whether to accept a liver graft for a specific recipient. In this context, livers from elderly donors are more frequently accepted for transplantation, to increase the donor pool and compensate the high waiting list mortality. In the current practice it is not unusual to accept 60-year old donor livers for transplantation, as the donor demographics have significantly changed over the years. However, controversy exists regarding the use of livers from donors above 70 or 80 years, particular in combination with other risk factors, e.g. liver steatosis, warm ischaemia or long cold storage. This review focuses first on the impact of ageing on liver morphology and function. Second, we will highlight outcome after transplantation from elderly donors. Finally, we describe further risk factors and donor-recipient selection under the scope of old donor organs and include our institutional experience and policy.

The Kupffer Cell Number Affects the Outcome of Living Donor Liver Transplantation from Elderly Donors

Background

There have been no previous reports how Kupffer cells affect the outcome of living donor liver transplantation (LDLT) with an elderly donor. The aim of this study was to elucidate the influence of Kupffer cells on LDLT.

Methods

A total of 161 adult recipients underwent LDLT. The graft survival, prognostic factors for survival, and graft failure after LDLT were examined between cases with a young donor (<50, n = 112) and an elderly donor (≥50, N = 49). The Kupffer cells, represented by CD68-positive cell in the graft, were examined in the young and elderly donors.

Results

In a multivariable analysis, a donor older than 50 years, sepsis, and diabetes mellitus were significant predictors of graft failure after LDLT. The CD68 in younger donors was significantly more expressed than that in elderly donors. The group with a less number of CD68-positive cells in the graft had a significantly poor survival in the elderly donor group and prognostic factor for graft failure.

Conclusions

The worse outcome of LDLT with elderly donors might be related to the lower number of Kupffer cells in the graft, which can lead to impaired recovery of the liver function and may predispose patients to infectious diseases after LDLT.

Extended-criteria donors in liver transplantation Part II: reviewing the impact of extended-criteria donors on the complications and outcomes of liver transplantation

Extended-criteria donors (ECDs) have an impact on early allograft dysfunction (EAD), biliary complications, relapse of hepatitis C virus (HCV), and survivals. Early allograft dysfunction was frequently seen in grafts with moderate and severe steatosis. Donors after cardiac death (DCD) have been associated with higher rates of graft failure and biliary complications compared to donors after brain death. Extended warm ischemia, reperfusion injury and endothelial activation trigger a cascade, leading to microvascular thrombosis, resulting in biliary necrosis, cholangitis, and graft failure. The risk of HCV recurrence increased by donor age, and associated with using moderately and severely steatotic grafts. With the administration of protease inhibitors sustained virological response was achieved in majority of the patients. Donor risk index and EC donor scores (DS) are reported to be useful, to assess the outcome. The 1-year survival rates were 87% and 40% respectively, for donors with a DS of 0 and 3. Graft survival was excellent up to a DS of 2, however a DS >2 should be avoided in higher-risk recipients. The 1, 3 and 5-year survival of DCD recipients was comparable to optimal donors. However ECDs had minor survival means of 85%, 78.6%, and 72.3%. The graft survival of split liver transplantation (SLT) was comparable to that of whole liver orthotopic liver transplantation. SLT was not regarded as an ECD factor in the MELD era any more. Full-right-full-left split liver transplantation has a significant advantage to extend the high quality donor pool. Hypothermic oxygenated machine perfusion can be applied clinically in DCD liver grafts. Feasibility and safety were confirmed. Reperfusion injury was also rare in machine perfused DCD livers.

Donor Factors Including Donor Risk Index Predict Fibrosis Progression, Allograft Loss, and Patient Survival following Liver Transplantation for Hepatitis C Virus

BACKGROUND

The utilization of liver transplantation (LT) is limited by the availability of suitable organs. This study aimed to assess the impact of the donor risk index (DRI) and other donor characteristics on fibrosis progression, graft, and patient survival in hepatitis C virus (HCV)-infected LT recipients.

METHODS

HCV-infected LT recipients who had at least 2 post-LT protocol liver biopsy specimens available were included. Hazard ratio for bivariate analysis was computed using Cox proportional hazard regression analysis.

RESULTS

Of 312 recipients, 26.6% died over a median follow-up of 58.5 months (95% CI: 46.5-67.3). Fourteen patients underwent re-transplantation. Mean time to graft failure was 84.3 months, median follow-up: 59 months, 95% CI (48.2, 68.3). DRI >1.5 was significantly associated with patient and graft survival (P = 0.04). Of the subset of 104 individuals who underwent histological analysis, 67.3% progressed to ≥F2. On multivariate analysis, significant donor-specific predictors of fibrosis progression were: donor age >50 years and DRI >1.7.

CONCLUSIONS

(1) Fibrosis progression in HCV-infected LT recipients is strongly associated with donor characteristics, specifically donor age and DRI. (2) DRI, an objective measure of donor quality, appears to correlate both with rate of histological progression and overall patient/graft survival.

Eurotransplant donor-risk-index and recipient factors: influence on long-term outcome after liver transplantation - A large single-center experience

The organ shortage has led to increased use of marginal organs. The Eurotransplant Donor-Risk-Index (ET-DRI) was established to estimate outcome after Liver Transplantation (LT). Currently, data on impact of ET-DRI on long-term outcome for different indications and recipient conditions are missing. Retrospective, single-center analysis of long-term graft survival (GS) of 1767 adult primary LTs according to indication, labMELDcategory (1: ≤18; 2: >18-25; 3: >25-35; 4: >35), and ET-DRI. Mean ET-DRI in our cohort was 1.63 (±0.43). One-, 10, and 15-yr GS was 83.5%, 63.3%, and 54.8%. Long-term GS was significantly influenced by ET-DRI. Accordingly, four ET-DRI categories were defined and analyzed with respect to underlying disease. Significant impact of these categories was observed for: Alcohol, cholestatic/autoimmune diseases (CD/AIH), and HCV, but not for HCC, HBV, cryptogenic cirrhosis, and acute liver failure. labMELD categories showed no significant influence on graft, but on patient survival. Matching ET-DRI categories with labMELD revealed significant differences in long-term GS for labMELDcategories 1, 2, and 3, but not 4. In multivariate analysis, HCV combined with ET-DRI > 2 and labMELDcategory 3 combined with ET-DRI > 2 emerged as negative predictors. To achieve excellent long-term graft survival, higher risk organs (ET-DRI > 1.4) should be used restrictively for patients with CD/AIH or HCV. Organs with ET-DRI > 2 should be avoided in patients with a labMELD of >25-35.

The corrected donor age for hepatitis C virus-infected liver transplant recipients

Donor age has become the dominant donor factor used to predict graft failure (GF) after liver transplantation (LT) in hepatitis C virus (HCV) recipients. The purpose of this study was to develop and validate a model of corrected donor age (CDA) for HCV LT recipients that transforms the risk of other donor factors into the scale of donor age. We analyzed all first LT recipients with HCV in the United Network for Organ Sharing (UNOS) registry from January 1998 to December 2007 (development cohort, n = 14,538) and January 2008 to December 2011 (validation cohort, n = 7502) using Cox regression, excluding early GF (<90 days from LT). Accuracy in predicting 1 year GF (death or repeat LT) was assessed with the net reclassification index (NRI). In the development cohort, after controlling for pre-LT recipient factors and geotemporal trends (UNOS region, LT year), the following donor factors were independent predictors of GF, all P < 0.05: donor age (hazard ratio [HR], 1.02/year), donation after cardiac death (DCD; HR, 1.31), diabetes (HR, 1.23), height < 160 cm (HR, 1.13), aspartate aminotransferase (AST) ≥ 120 U/L (HR, 1.10), female (HR, 0.94), cold ischemia time (CIT; HR, 1.02/hour), and non-African American (non-AA) donor-African American (AA) recipient (HR, 1.65). Transforming these risk factors into the donor age scale yielded the following: DCD = +16 years; diabetes = +12 years; height < 160 cm = +7 years; AST ≥ 120 U/L = +5 years; female = -4 years; and CIT = +1 year/hour > 8 hours and -1 year/hour < 8 hours. There was a large effect of donor-recipient race combinations: +29 years for non-AA donor and an AA recipient but only +5 years for an AA donor and an AA recipient, and -2 years for an AA donor and a non-AA recipient. In a validation cohort, CDA better classified risk of 1-year GF versus actual age (NRI, 4.9%; P = 0.009) and versus the donor risk index (9.0%, P < 0.001). The CDA, compared to actual donor age, provides an intuitive and superior estimation of graft quality for HCV-positive LT recipients because it incorporates additional factors that impact LT GF rates.

Expanded criteria donors

The greatest challenge facing liver transplantation today is the shortage of donor livers. Demand far exceeds supply, and this deficit has driven expansion of what is considered an acceptable organ. The evolving standard has not come without costs, however, as each new frontier of expanded donor quality (i.e., advancing donor age, donation after cardiac death, and split liver) may have traded wait-list for post-transplant morbidity and mortality. This article delineates the nature and severity of risk associated with specific deceased donor liver characteristics and recommends strategies to maximally mitigate these risks.

The impact of hepatitis C burden: an evidence-based approach

BACKGROUND

Infection with the hepatitis C virus (HCV) has been considered a major cause of mortality, morbidity and resource utilisation in the US. In addition, HCV is the main cause of hepatocellular cancer (HCC) in the US. Recent developments in the diagnosis and treatment of HCV, including new recommendations pertaining to screening for HCV by the Centers for Disease Control and Prevention and newer treatment regimens with high efficacy, short duration and the potential for interferon-free therapies, have energised the health care practitioners regarding HCV management.

AIM

To assess the full impact of HCV burden on clinical, economic and patient-reported outcomes.

METHODS

An expert panel was convened to assess the full impact of HCV burden on a number of important outcomes using an evidence-based approach predicated on Grading of Recommendations Assessment, Development and Evaluation methodology. The literature was summarised, graded using an evidence-based approach and presented during the workshop. Workshop presentations were intended to review recent, relevant evidence-based literature and provide graded summary statements pertaining to HCV burden on topics including the relationships between HCV and the development of important outcomes.

RESULTS

The associations of HCV with cirrhosis, HCC, liver-related mortality, type 2 diabetes mellitus, rheumatological diseases and quality of life impairments are supported by strong evidence. Also, there is strong evidence that sustained viral eradication of HCV can improve important outcomes such as mortality and quality of life.

CONCLUSIONS

The current evidence suggests that HCV has been associated with tremendous clinical, economic and quality of life burden.

Deceased donor risk factors influencing liver transplant outcome

As the pressure for providing liver transplantation to more and more candidates increases, transplant programs have begun to consider deceased donor characteristics that were previously considered unacceptable. With this trend, attention has focused on better defining those donor factors that can impact the outcome of liver transplantation. This review examines deceased donor factors that have been associated with patient or graft survival as well as delayed graft function and other liver transplant results.