Impact of the donor risk index on the outcome of hepatitis C virus-positive liver transplant recipients

The utility of machine learning for predicting donor discard in abdominal transplantation

BACKGROUND

Increasing access and better allocation of organs in the field of transplantation is a critical problem in clinical care. Limitations exist in accurately predicting allograft discard. Potential exists for machine learning to provide a balanced assessment of the potential for an organ to be used in a transplantation procedure.

METHODS

We accessed and utilized all available deceased donor United Network for Organ Sharing data from 1987 to 2020. With these data, we evaluated the performance of multiple machine learning methods for predicting organ use. The machine learning methods trialed included XGBoost, random forest, Naïve Bayes (NB), logistic regression, and fully connected feedforward neural network classifier methods. The top two methods, XGBoost and random forest, were fully developed using 10-fold cross-validation and Bayesian optimization of hyperparameters.

RESULTS

The top performing model at predicting liver organ use was an XGBoost model which achieved an AUC-ROC of .925, an AUC-PR of .868, and an F1 statistic of .756. The top performing model for predicting kidney organ use classification was an XGBoost model which achieved an AUC-ROC of .952, and AUC-PR of .883, and an F1 statistic of .786.

CONCLUSIONS

The XGBoost method demonstrated a significant improvement in predicting donor allograft discard for both kidney and livers in solid organ transplantation procedures. Machine learning methods are well suited to be incorporated into the clinical workflow; they can provide robust quantitative predictions and meaningful data insights for clinician consideration and transplantation decision-making.

Impact of Donation After Circulatory Death Allografts on Outcomes After Liver Transplant for Hepatitis C: A Single-Center Experience and Review of the Literature

OBJECTIVES

We investigated the impact of liver transplant from donors after circulatory death on incidence and severity of recurrent hepatitis C virus infection, graft and patient survival and aimed to identify predictors of outcomes.

MATERIALS AND METHODS

We retrospectively reviewed all liver transplants performed at a single center (July 2007-February 2014). Patients with hepatitis C who underwent liver transplant from donors after circulatory death (group 1) were compared with hepatitis C patients who received grafts from donors after brain death (group 2) and patients without hepatitis C who received grafts from donors after circulatory death (group 3).We used the Kaplan-Meier method for survival analysis and performed a multivariable analysis for predictors of outcomes using Cox regression. Competing risk was used to analyze hepatitis C recurrence.

RESULTS

Of 196 patients, 107 were included: 25 in group 1, 46 in group 2, and 36 in group 3. All 3 groups were comparable, except for longer cold ischemia time (P < .01) in group 1, lower Model for End-Stage Liver Disease score at transplant in groups 1 and 3 (P < .01), and greater proportion of recipients with hepatocellular carcinoma in groups 1 and 2 (P = .02). Hepatitis C recurrence and severe recurrence at 1 and 3 years were higher in group 1 (but not statistically significant). Severe recurrence was noted in 17% versus 8% at 1 year (P = .12) and 30% versus 14% at 3 years (P = .08). Graft and patient survival rates at 1, 3, and 5 years were comparable in all 3 study groups.

CONCLUSIONS

Recurrent hepatitis C, including severe recurrence, was greater following donation after circulatory death compared with donation after brain death liver transplant. However, graft survival and patient survival were comparable, including in recipients of donation after circulatory death grafts without hepatitis C.

Liver Transplantation in Acute-on-chronic Liver Failure

Liver transplantation (LT) has revolutionized outcomes for cirrhotic patients. Current liver allocation policies dictate patients with highest short-term mortality receive the highest priority, thus, several patients become increasingly ill on the waitlist. Given cirrhosis is a progressive disease, it can be complicated by the occurrence of acute-on-chronic liver failure (ACLF), a syndrome defined by an acute deterioration of liver function associated with extrahepatic organ failures requiring intensive care support and a high short-term mortality. Successfully bridging to transplant includes accurate prognostication and prioritization of ACLF patients awaiting LT, optimizing intensive care support pre-LT, and tailoring immunosuppressive and anti-infective therapies post-LT. Furthermore, predicting futility (too sick to undergo LT) in ACLF is challenging. In this review, we summarize the role of LT in ACLF specifically highlighting (a) current prognostic scores in ACLF, (b) critical care management of the ACLF patient awaiting LT, (c) donor issues to consider in transplant in ACLF, and (d) exploring of recent post-LT outcomes in ACLF and potential opportunities to improve outcomes including current care gaps and unmet research needs.

Extended criteria grafts and emerging therapeutics strategy in liver transplantation. The unstable balance between damage and repair

Due to increasing demand for donor organs, "extended criteria" donors are increasingly considered for liver transplantation, including elderly donors and donors after cardiac death. The grafts of this subgroup of donors share a major risk to develop significant features of ischemia reperfusion injury, that may eventually lead to graft failure. Ex-situ machine perfusion technology has gained much interest in liver transplantation, because represents both a useful tool for improving graft quality before transplantation and a platform for the delivery of therapeutics directly to the organ. In this review, we survey ongoing clinical evidences supporting the use of elderly and DCD donors in liver transplantation, and the underlying mechanistic aspects of liver aging and ischemia reperfusion injury that influence graft quality and transplant outcome. Finally, we highlight evidences in the field of new therapeutics to test in MP in the context of recent findings of basic and translational research.

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.

Use of Elderly Donors in Liver Transplantation: A Paired-match Analysis at a Single Center

OBJECTIVE

To evaluate the use of elderly donors in liver transplantation (LT) and identify risk factors associated with a worse outcome.

SUMMARY BACKGROUND DATA

Use of livers from very old donors could expand the donor pool but is not universally implemented.

METHODS

This is a retrospective, single-center medical record review. From January 2001 to December 2014, 1354 LTs were performed. After exclusion of donors <18 years, ABO-incompatible LT, re-LT and UNOS 1 status patients, LT recipients were stratified into 2 groups based on donor age: 18-69 (n=692) vs. ≥70 years (n=515) then matched using a propensity score approach. Two groups were finally matched (young group = 448 cases; old group = 515 cases).

RESULTS

The median (interquartile range [IQR]) follow-up was 5.0 (2.0-8.4) years. Comparing the 2 identified groups, no differences were observed regarding early retransplants (1.8 vs. 2.9; P = 0.3), HCV-related death (7.6 vs. 8.7%; P = 0.6), vascular (5.8 vs. 5.0%; P = 0.7), and biliary complications (16.5 vs. 18.6%; P = 0.4). On multivariate analysis, independent risk factors for graft loss were: HCV-positive recipient (HR = 2.1; 95% CI = 1.6-2.7; P < 0.001), donor age (HR = 1.0; 95% CI = 1.0-1.0; P < 0.001), cold ischemia time (HR = 1.0; 95% CI = 1.0-1.0; P = 0.042), and donor history of diabetes mellitus (HR = 1.48; 95% CI = 1.03-2.13; P = 0.036).

CONCLUSIONS

Use of elderly donors is not associated per se with an increased risk of vascular and biliary complications. In the presence of cold ischemia time and diabetes mellitus, appropriate donor-to-recipient matching is warranted.

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.

High Center Volume Does Not Mitigate Risk Associated with Using High Donor Risk Organs in Liver Transplantation

BACKGROUND

High-risk donor allografts increase access to liver transplant, but potentially reduce patient and graft survival.

AIMS

It is unclear whether the risk associated with using marginal donor livers is mitigated by increasing center experience.

METHODS

The United Network for Organ Sharing registry was queried for adult first-time liver transplant recipients between 2/2002 and 12/2015. High donor risk was defined as donor risk index >1.9, and 1-year patient and graft survival were compared according to donor risk index in small and large centers. Multivariable Cox regression estimated the hazard ratio (HR) associated with using high-risk donor organs, according to a continuous measure of annual center volume.

RESULTS

The analysis included 51,770 patients. In 67 small and 67 large centers, high donor risk index predicted increased mortality (p = 0.001). In multivariable analysis, high-donor risk index allografts predicted greater mortality hazard at centers performing 20 liver transplants per year (HR 1.35; 95% CI 1.22, 1.49; p < 0.001) and, similarly, at centers performing 70 per year (HR 1.35; 95% CI 1.26, 1.43; p < 0.001). The interaction between high donor risk index and center volume was not statistically significant (p = 0.747), confirming that the risk associated with using marginal donor livers was comparable between smaller and larger centers. Results were consistent when examining graft loss.

CONCLUSION

At both small and large centers, high-risk donor allografts were associated with reduced patient and graft survival after liver transplant. Specific strategies to mitigate the risk of liver transplant involving high-risk donors are needed, in addition to accumulation of center expertise.

The donor risk index: A decade of experience

In 2006, derivation of the donor risk index (DRI) highlighted the importance of donor factors for successful liver transplantation. Over the last decade, the DRI has served as a useful metric of donor quality and has enhanced our understanding of donor factors and their impact upon recipients with hepatitis C virus, those with low Model for End-Stage Liver Disease (MELD) score, and individuals undergoing retransplantation. DRI has provided the transplant community with a common language for describing donor organ characteristics and has served as the foundation for several tools for organ risk assessment. It is a useful tool in assessing the interactions of donor factors with recipient factors and their impact on posttransplant outcomes. However, limitations of statistical modeling, choice of donor factors, exclusion of unaccounted donor and geographic factors, and the changing face of the liver transplant recipient have tempered its widespread use. In addition, the DRI was derived from data before the MELD era but is currently being applied to expand the donor pool while concurrently meeting the demands of a dynamic allocation system. A decade after its introduction, DRI remains relevant but may benefit from being updated to provide guidance in the use of extended criteria donors by accounting for the impact of geography and unmeasured donor characteristics. DRI could be better adapted for recipients with nonalcoholic fatty liver disease by examining and including recipient factors unique to this population. Liver Transplantation 23 1216-1225 2017 AASLD.

Factors Associated With Short- and Long-term Liver Graft Survival in the United Kingdom: Development of a UK Donor Liver Index

BACKGROUND

A measure of donor liver quality, the donor liver index, was developed and validated for the UK population of transplant recipients. Unlike previously proposed measures, this index is only based on variables that are available at the point of retrieval, and so does not include cold ischemic time.

METHODS

Indices of liver quality were based on data from the UK Transplant Registry on all 7929 liver transplants between January 2000 and December 2014.

RESULTS

The donor liver index (DLI) was based on factors shown to affect graft survival, which included donor age, sex, height, type (donor after brain death or circulatory death), bilirubin, smoking history, and whether the liver was split. A separate index (DLI1) looking at 1-year survival showed donor cardiac disease, black ethnicity, and steatosis to be additional risk factors. A strong association was found between DLI and whether or not a surgeon accepts an offered liver for transplant, with a marked fall in acceptance rates for livers with an index greater than 1.31. Since 2000, there has been a notable reduction in the quality of livers transplanted, coupled with variation between the 7 UK liver transplant centers in risk appetite.

CONCLUSIONS

The DLI is an index of liver quality which enables analysis of the changing trends in liver quality and center behavior. DLI1 enables identification of factors affecting shorter-term survival, and perhaps identifies a cohort of livers that may benefit from novel preservation technologies.

The role of extended criteria donors in liver transplantation for nonalcoholic steatohepatitis

BACKGROUND

Nonalcoholic steatohepatitis is expected to become the leading indication for liver transplantation. Use of extended criteria donors (ECD) may help with donor allocation in these patients. The objective of this study was to determine the use of ECDs in patients with nonalcoholic steatohepatitis undergoing liver transplantation to stimulate a liver-specific predictive model for ECD use.

METHODS

The United Network for Organ Sharing database was used to identify patients undergoing liver transplantation for nonalcoholic steatohepatitis (2002-2014). Cox hazards models were created using (1) United Network for Organ Sharing ECD criteria (based on kidney allocation), (2) individual donor characteristics (age, sex, race, cause of death, body mass index, cold ischemic time), and (3) the Kidney Donor Profile Index (KDPI) to examine the effect of ECDs on mortality and graft failure.

RESULTS

A total of 4,387 patients underwent liver transplantation for nonalcoholic steatohepatitis; 1,359 (30.9%) patients received an ECD. Transplantation with ECD livers had comparable patient survival (hazard ratio [HR] 1.06, 95% confidence interval [CI] 0.91-1.23) between donor types but an increased risk of graft failure (HR 1.18, 95% CI 1.03-1.36) compared to standard donors. Individual characteristics did not affect patient survival or graft failure. A 10% increase in KDPI was associated with a 28% increase in patient mortality (HR 1.28, 95% CI 1.02-1.60) and 45% increase in graft failure (HR 1.45, 95% CI 1.18-1.80).

CONCLUSION

Based on the current United Network for Organ Sharing definition, ECDs in nonalcoholic steatohepatitis were associated with similar overall survival but increased risk of graft failure. Given the shortage of organs, creation of an easily calculated, liver-specific model similar to the KDPI may help risk stratify patients and improve organ allocation.

Key donor factors associated with graft loss among liver transplant recipients with human immunodeficiency virus

BACKGROUND

Human immunodeficiency virus (HIV)-infected liver transplant (LT) recipients have higher risk of graft loss than HIV-uninfected recipients. As the original donor risk index excluded HIV-positive patients, donor factors associated with graft loss in HIV-positive recipients are unknown.

METHODS

Identifying all HIV-positive patients in the Scientific Registry of Transplant Recipients, supplemented by all HIV-infected patients in the solid organ transplantation in HIV: Multi-Site Study (HIV-TR), we evaluated donor factors associated with graft loss among HIV-positive recipients transplanted between March 2002 and August 2012.

RESULTS

A total of 249 HIV-positive LT recipients were followed for median 2.4 (interquartile range [IQR]: 0.8-4.9) years. In univariate analysis, donor diabetes (HR=2.09; P=.002) and donor hypertension (HR=1.43; P=.048) were significantly associated with graft loss, and African-American (AA) recipient:non-AA donor race mismatch (HR=1.60; P=.07), other cause of donor death compared to trauma (HR=2.02; P=.09), and donor age 30 years or older (HR=1.53; P=.05) were of borderline significance. In multivariate analysis, donor diabetes (HR=2.12; 95% CI: 1.33-3.38; P=.002) was the only significant predictor of graft loss.

CONCLUSION

In HIV-positive LT recipients, risk of graft loss is strongly influenced by donor diabetes. This information may be useful to transplant physicians seeking to optimize overall graft survival in their HIV-positive LT recipients.

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.

Elderly donor liver grafts are not associated with a higher incidence of biliary complications after liver transplantation: results of a national multicenter study

BACKGROUND

Liver transplantation with livers grafts from elderly donors has been associated with a higher risk of biliary complications. The aim of this study was to examine whether our national protocol could contribute to a lower incidence of biliary complications.

METHODS

All adult recipients in the Netherlands transplanted with a liver from an elderly donor (≥ 65 yrs; n = 68) in the period January 2000-July 2011 were matched with recipients of a liver from a donor <65 yr (n = 136). Outcome parameters were 90-d, one-yr, and three-yr patient/graft survival rates, biliary complications (non-anastomotic stricture, anastomotic stricture, biliary leakage, and post-transplant cholangitis), and postoperative hepatic ischemic injury serum markers (AST/ALT).

RESULTS

The median cold ischemia time (CIT) was 7:25 (h:min) in the group recipients of an elderly donor liver graft. Ninety-day, one-yr, and three-yr patient/graft survival rates were similar between the group with an elderly donor liver and their younger controls. Moreover, no differences were found in the incidence of biliary complications and postoperative levels of AST/ALT between the two groups.

CONCLUSION

Transplantation of livers from elderly donors (≥ 65 yr) is not associated with a higher incidence of biliary complications, in a national policy wherein the CIT is kept short.

Recurrent HCV after liver transplantation-mechanisms, assessment and therapy

Chronic HCV infection is the leading indication for liver transplantation. However, as a result of HCV recurrence, patient and graft survival after liver transplantation are inferior compared with other indications for transplantation. HCV recurrence after liver transplantation is associated with considerable mortality and morbidity. The development of HCV-related fibrosis is accelerated after liver transplantation, which is influenced by a combination of factors related to the virus, donor, recipient, surgery and immunosuppression. Successful antiviral therapy is the only treatment that can attenuate fibrosis. The advent of direct-acting antiviral agents (DAAs) has changed the therapeutic landscape for the treatment of patients with HCV. DAAs have improved tolerability, and can potentially be used without PEG-IFN for a shorter time than previous therapies, which should result in better outcomes. In this Review, we describe the important risk factors that influence HCV recurrence after liver transplantation, highlighting the mechanisms of fibrosis and the integral role of hepatic stellate cells. Indirect and direct assessment of fibrosis, in addition to new antiviral therapies, are also discussed.

The impact of type 2 diabetes and obesity on the long-term outcomes of more than 85 000 liver transplant recipients in the US

BACKGROUND

Type 2 diabetes is known to negatively impact the outcome of chronic liver disease.

AIM

To evaluate the impact of diabetes on the outcomes of liver transplants (LT).

METHODS

Study cohort included adults (>18 years) who received LT in the US between 1994 and 2013 (The Scientific Registry of Transplant Recipients). Pre- and post-transplant diabetes was recorded in patients with mortality follow-up.

RESULTS

We included 85 194 liver transplant recipients. Of those, 11.2% had history of pre-transplant diabetes. The most common indications for liver transplant were hepatitis C (36.4%), alcohol-related liver disease (20.6%), primary liver malignancy of unspecified aetiology (14.7%), cryptogenic cirrhosis (8.0%), hepatitis B (4.6%) and non-alcoholic steatohepatitis (3.9%). A total of 96.5% transplants were from deceased donors, and 7.9% donors had history of diabetes. During an average 6.5 years of follow-up, 31.3% recipients died and 8.8% had a graft failure. In multivariate survival analysis [at least 5 years of cohort follow-up (N = 35 870)], after adjustment for age, ethnicity, insurance type, history of chronic diseases, HCV infection and noncompliance, independent predictors of recipient mortality included the presence of pre-transplant diabetes [adjusted hazard ratio (95%CI) = 1.21 (1.12-1.30)] and developing diabetes post-transplant [1.06 (1.02-1.11)]. Donor's history of diabetes was also independently associated with higher mortality [1.10 (1.02-1.19)]. Furthermore, donor's history of diabetes was also associated with an increased the risk of liver graft failure [1.35 (1.24-1.47)].

CONCLUSIONS

Presence of type 2 diabetes pre- and post-transplant, as well as presence of type 2 diabetes in the donors, are all associated with an increased risk of adverse post-transplant outcomes.

Post-liver transplant hepatitis C virus recurrence: an unresolved thorny problem

Hepatitis C virus (HCV)-related cirrhosis represents the leading cause of liver transplantation in developed, Western and Eastern countries. Unfortunately, liver transplantation does not cure recipient HCV infection: reinfection universally occurs and disease progression is faster after liver transplant. In this review we focus on what happens throughout the peri-transplant phase and in the first 6-12 mo after transplantation: during this crucial period a completely new balance between HCV, liver graft, the recipient's immune response and anti-rejection therapy is achieved that will deeply affect subsequent outcomes. Nearly all patients show an early graft reinfection, with HCV viremia reaching and exceeding pre-transplant levels; in this setting, histological assessment is essential to differentiate recurrent hepatitis C from acute or chronic rejection; however, differentiating the two patterns remains difficult. The host immune response (mainly cellular mediated) appears to be crucial both in the control of HCV infection and in the genesis of rejection, and it is also strongly influenced by immunosuppressive treatment. At present no clear immunosuppressive strategy could be strongly recommended in HCV-positive recipients to prevent HCV recurrence, even immunotherapy appears to be ineffective. Nonetheless it seems reasonable that episodes of rejection and over-immunosuppression are more likely to enhance the risk of HCV recurrence through immunological mechanisms. Both complete prevention of rejection and optimization of immunosuppression should represent the main goals towards reducing the rate of graft HCV reinfection. In conclusion, post-transplant HCV recurrence remains an unresolved, thorny problem because many factors remain obscure and need to be better determined.

Hepatitis viruses and liver transplantation: evolving trends in antiviral management

Viral hepatitis is both a leading indication for liver transplant (LT) and an important cause of posttransplant graft loss and mortality. Treatment and prevention of hepatitis B virus in LT recipients, with the observed corresponding improvement in post-LT outcomes, is among the great success stories in transplantation. By comparison, treatment of hepatitis C virus with safe and effective regimens is only just becoming a reality. Chronic hepatitis E virus infection in LT recipients represents a newly described phenomenon that can also lead to graft loss; early diagnosis and treatment may be key in the management of these patients.

Outcomes of living donor liver transplantation for hepatitis C virus-positive recipients in Japan: results of a nationwide survey

A nationwide survey of living donor liver transplantation (LDLT) for hepatitis C virus (HCV)-positive recipients was performed in Japan. A total of 514 recipients are reported and included in the study. The cumulative patient survival rate at 5 and 10 years was 72% and 63%, respectively. Of the 514 recipients, 142 patients (28%) died until the end of the observation, among which the leading cause was recurrent hepatitis C (42 cases). According to Cox regression multivariate analysis, donor age (>40), non-right liver graft, acute rejection episode, and absence of a sustained virologic response were independent prognostic factors. Of the 514 recipients, 361 underwent antiviral treatment mainly with pegylated-interferon and ribavirin (preemptive treatment in 150 patients and treatment for confirmed recurrent hepatitis in 211). The dose reduction rate and discontinuation rate were 40% and 42%, respectively, with a sustained virologic response rate of 43%. In conclusion, patient survival of HCV-positive recipients after LDLT was good, with a 10-year survival of 63%. Right liver graft might be preferable for HCV-positive recipients in an LDLT setting.

[Deceased donor liver transplantation]

Deceased donor liver transplantation is nowadays a routine procedure for the treatment of terminal liver failure and often represents the only chance of a cure. Under given optimal conditions excellent long-term results can be obtained with 15-year survival rates of well above 60 %.In Germany the outcome after liver transplantation has deteriorated since the introduction of an allocation policy, which is based on the medical urgency. At present 25 % of liver graft recipients die within the first year after transplantation. In contrast 1-year survival in most other countries, e.g. in the USA or the United Kingdom is around 90 % and therefore significantly better. Reasons for the inferior results in Germany are on the one hand an increasing number of critically ill recipients and on the other hand an unfavorable situation for organ donation. In comparison with other countries the organ donation rate is low and moreover the risk profile of these donors is above average. This combination of organ shortage and organ allocation represents a big challenge for the future orientation of liver transplantation and creates the potential for conflict. These cannot be solved on a medical basis but require a social consensus.Because of the present inferior results and because of the high expenses of the present system we suggest a discussion on future allocation policies as well as on future centre structures in Germany. In addition to the medical urgency the maximum benefit should also be considered for organ allocation.

Donor Risk Index for African American liver transplant recipients with hepatitis C virus

African American (AA) liver transplant (LT) recipients with hepatitis C virus (HCV) have higher rates of graft loss than other racial/ethnic groups. The Donor Risk Index (DRI) predicts graft loss but is neither race- nor disease-specific and may not be optimal for assessing donor risk for AA HCV-positive LT recipients. We developed a DRI for AA with HCV with the goal of enhancing graft loss predictions. All U.S. HCV-positive adult AA first deceased donor LTs surviving ≥30 days from March 2002 to December 2009 were included. A total of 1,766 AA LT recipients were followed for median 2.8 (interquartile range [IQR] 1.3-4.9) years. Independent predictors of graft loss were donor age (40-49 years: hazard ratio [HR] 1.54; 50-59 years: HR 1.80; 60+ years: HR 2.34, P < 0.001), non-AA donor (HR 1.66, P < 0.001), and cold ischemia time (CIT) (HR 1.03 per hour >8 hours, P = 0.03). Importantly, the negative effect of increasing donor age on graft and patient survival among AAs was attenuated by receipt of an AA donor. A new donor risk model for AA (AADRI-C) consisting of donor age, race, and CIT yielded 1-year, 3-year, and 5-year predicted graft survival rates of 91%, 77%, and 68% for AADRI <1.60; 86%, 67%, and 55% for AADRI 1.60-2.44; and 78%, 53%, and 39% for AADRI >2.44. In the validation dataset, AADRI-C correctly reclassified 27% of patients (net reclassification improvement P = 0.04) compared to the original DRI.

CONCLUSION

AADRI-C identifies grafts at higher risk of failure and this information is useful for risk-benefit discussions with recipients. Use of AA donors allows consideration of older donors.

Hepatitis C infection and hepatocellular carcinoma in liver transplantation: a 20-year experience

BACKGROUND

Hepatitis C infection (HCV) and hepatocellular carcinoma (HCC), the two main causes of liver transplantation (LT), have reduced survival post-LT. The impact of HCV, HCC and their coexistence on post-LT survival were assessed.

METHODOLOGY

All 601 LT patients from 1992 to 2011 were reviewed. Those deceased within 30 days (n = 69) and re-transplants (n = 49) were excluded. Recipients were divided into four groups: (a) HCC-/HCV-(n = 252) (b) HCC+/HCV- (n = 58), (c) HCC-/HCV+ (n = 106) and (d) HCC+/HCV+ (n = 67). Demographics, the donor risk index (DRI), Model for End-Stage Liver Disease (MELD) score, survival, complications and tumour characteristics were collected. Statistical analysis included anova, chi-square, Fisher's exact tests and Cox and Kaplan-Meier for overall survival.

RESULTS

Groups were comparable with regards to baseline characteristics, but HCC patients were older. After adjusting for age, MELD, gender and the donor risk index (DRI), survival was lower in the HCC+/HCV+ group (59.5% at 5 yrs) and the hazard ratio (HR) was 1.90 [95% confidence interval (CI),1.24-2.95, P = 0.003] and 1.45 (95% CI, 0.99-2.12, P = 0.054) for HCC-/HCV+. HCC survival was similar to controls (HR 1.18, 95% CI, 0.71-1.93, P = 0.508). HCC+/HCV- patients exceeded the Milan criteria (50% versus 31%, P < 0.04) and had more micro-vascular invasion (37.5% versus 20.6%, P = 0.042). HCC+/HCV+ versus HCC+/HCV- survival remained lower (HR 1.94, 95% CI, 1.06-3.81, P = 0.041) after correcting for tumour characteristics and treatment.

CONCLUSION

HCV patients had lower survival post-LT. HCC alone had no impact on survival. Patient survival decreased in the HCC+/HCV+ group and this appears to be as a consequence of HCV recurrence.

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.

Living-donor liver transplantation and hepatitis C

Hepatitis-C-virus- (HCV-) related end-stage cirrhosis is the primary indication for liver transplantation in many countries. Unfortunately, however, HCV is not eliminated by transplantation and graft reinfection is universal, resulting in fibrosis, cirrhosis, and finally graft decompression. In areas with low deceased-donor organ availability like Japan, living-donor liver transplantation (LDLT) is similarly indicated for HCV cirrhosis as deceased-donor liver transplantation (DDLT) in Western countries and accepted as an established treatment for HCV-cirrhosis, and the results are equivalent to those of DDLT. To prevent graft failure due to recurrent hepatitis C, antiviral treatment with pegylated-interferon and ribavirin is currently considered the most promising regimen with a sustained viral response rate of around 30% to 35%, although the survival benefit of this regimen remains to be investigated. In contrast to DDLT, many Japanese LDLT centers have reported modified treatment regimens as best efforts to secure first graft, such as aggressive preemptive antiviral treatment, escalation of dosages, and elongation of treatment duration.

Outcome of HCV/HIV-coinfected liver transplant recipients: a prospective and multicenter cohort study

Eighty-four HCV/HIV-coinfected and 252-matched HCV-monoinfected liver transplant recipients were included in a prospective multicenter study. Thirty-six (43%) HCV/HIV-coinfected and 75 (30%) HCV-monoinfected patients died, with a survival rate at 5 years of 54% (95% CI, 42-64) and 71% (95% CI, 66 to 77; p = 0.008), respectively. When both groups were considered together, HIV infection was an independent predictor of mortality (HR, 2.202; 95% CI, 1.420-3.413 [p < 0.001]). Multivariate analysis of only the HCV/HIV-coinfected recipients, revealed HCV genotype 1 (HR, 2.98; 95% CI, 1.32-6.76), donor risk index (HR, 9.48; 95% CI, 2.75-32.73) and negative plasma HCV RNA (HR, 0.14; 95% CI, 0.03-0.62) to be associated with mortality. When this analysis was restricted to pretransplant variables, we identified three independent factors (HCV genotype 1, pretransplant MELD score and centers with <1 liver transplantation/year in HIV-infected patients) that allowed us to identify a subset of 60 (71%) patients with a similar 5-year prognosis (69%[95% CI, 54-80]) to that of HCV-monoinfected recipients. In conclusion, 5-year survival in HCV/HIV-coinfected liver recipients was lower than in HCV-monoinfected recipients, although an important subset with a favorable prognosis was identified in the former.

A score predicting survival after liver retransplantation for hepatitis C virus cirrhosis

BACKGROUND

Approximately one fourth of patients transplanted for hepatitis C virus (HCV)-induced liver failure progress to cirrhosis within 5 years, potentially requiring retransplantation. Although the relisting decision can be difficult in these patients, a score could help in selection of candidates with the best potential outcomes.

METHODS

A total of 1422 HCV-positive patients having undergone a retransplantation were included in this registry-based study. A multivariate Cox regression was performed, and an Akaike procedure was applied to design a score predicting survival after retransplantation and to allow an internal validation. Retained variables were donor age (DnAge), serum creatinine (Creat), International Normalized Ratio (INR), and serum albumin (Alb) at the second transplantation, recipient age (RecAge) at the first transplantation, and the interval between both transplantations (Int).

RESULTS

The score was designed as 0.23×DnAge+4.86×log Creat-2.45×log Int+2.69×INR+0.10×RecAge-3.27× Alb+40. The receiver operating characteristic area under curve was 0.643 at 3 years, and survivals were 71%, 56%, and 37% for scores <30, 30 to 40, and >40, respectively (log rank <0.0001).

CONCLUSIONS

Overall, the proposed score is specifically designed for HCV-positive patients, accurately predicts survival after a liver retransplantation, and is helpful in the selection of candidates with the best potential outcomes.

Development of organ-specific donor risk indices

Because of the shortage of deceased donor organs, transplant centers accept organs from marginal deceased donors, including older donors. Organ-specific donor risk indices have been developed to predict graft survival with various combinations of donor and recipient characteristics. Here we review the kidney donor risk index (KDRI) and the liver donor risk index (LDRI) and compare and contrast their strengths, limitations, and potential uses. The KDRI has a potential role in developing new kidney allocation algorithms. The LDRI allows a greater appreciation of the importance of donor factors, particularly for hepatitis C virus-positive recipients; as the donor risk index increases, the rates of allograft and patient survival among these recipients decrease disproportionately. The use of livers with high donor risk indices is associated with increased hospital costs that are independent of recipient risk factors, and the transplantation of livers with high donor risk indices into patients with Model for End-Stage Liver Disease scores < 15 is associated with lower allograft survival; the use of the LDRI has limited this practice. Significant regional variations in donor quality, as measured by the LDRI, remain in the United States. We also review other potential indices for liver transplantation, including donor-recipient matching and the retransplant donor risk index. Although substantial progress has been made in developing donor risk indices to objectively assess donor variables that affect transplant outcomes, continued efforts are warranted to improve these indices to enhance organ allocation policies and optimize allograft survival.

Liver transplantation for hepatitis C from donation after cardiac death donors: an analysis of OPTN/UNOS data

Donation after cardiac death (DCD) liver transplantation is increasing largely because of a shortage of organs. However, there are almost no data that have specifically assessed the impact of using DCD livers for HCV patients. We retrospectively studied adult primary DCD liver transplantation (630 HCV, 1164 non-HCV) and 54 129 donation after brain death (DBD) liver transplantation between 2002 and 2009 using the UNOS/OPTN database. With donation after brain death (DBD) livers, HCV recipients had significantly inferior graft survival compared to non-HCV recipients (p < 0.0001). Contrary to DBD donors, DCD livers used in HCV patients showed no difference in graft survival compared to non-HCV patients (p = 0.5170). Cox models showed DCD livers and HCV disease had poorer graft survival (HR = 1.80 and 1.28, p < 0.0001, respectively). However, the hazard ratio of DCD and HCV interaction was 0.80 (p = 0.02) and these results suggest that DCD livers on HCV disease do not fare worse than DCD livers on non-HCV disease. The graft survival of recent years (2006-2009) was significantly better than that in former years (2002-2005) (p = 0.0482). In conclusion, DCD liver transplantation for HCV disease showed satisfactory outcomes. DCD liver transplantation can be valuable option for HCV related end-stage liver disease.

Liver transplantation and hepatitis C

Hepatitis-C-virus- (HCV-) related end-stage cirrhosis is the primary indication for liver transplantation in many countries. Unfortunately, however, HCV is not eliminated by transplantation and graft reinfection is universal, resulting in fibrosis, cirrhosis, and finally graft decompensation. The use of poor quality organs, particularly from older donors, has a highly negative impact on the severity of recurrence and patient/graft survival. Although immunosuppressive regimens have a considerable impact on the outcome, the optimal regimen after liver transplantation for HCV-infected patients remains unclear. Disease progression monitoring with protocol biopsy and new noninvasive methods is essential for predicting patient/graft outcome and starting antiviral treatment with the appropriate timing. Antiviral treatment with pegylated interferon and ribavirin is currently considered the most promising regimen with a sustained viral response rate of around 30% to 35%, although the survival benefit of this regimen remains to be investigated. Living-donor liver transplantation is now widely accepted as an established treatment for HCV cirrhosis and the results are equivalent to those of deceased donor liver transplantation.

Balancing donor and recipient risk factors in liver transplantation: the value of D-MELD with particular reference to HCV recipients

Donor-recipient match is a matter of debate in liver transplantation. D-MELD (donor age × recipient biochemical model for end-stage liver disease [MELD]) and other factors were analyzed on a national Italian database recording 5946 liver transplants. Primary endpoint was to determine factors predictive of 3-year patient survival. D-MELD cutoff predictive of 5-year patient survival <50% (5yrsPS<50%) was investigated. A prognosis calculator was implemented (http://www.D-MELD.com). Differences among D-MELD deciles allowed their regrouping into three D-MELD classes (A < 338, B 338-1628, C >1628). At 3 years, the odds ratio (OR) for death was 2.03 (95% confidence interval [CI], 1.44-2.85) in D-MELD class C versus B. The OR was 0.40 (95% CI, 0.24-0.66) in class A versus class B. Other predictors were hepatitis C virus (HCV; OR = 1.42; 95% CI, 1.11-1.81), hepatitis B virus (HBV; OR = 0.69; 95% CI, 0.51-0.93), retransplant (OR = 1.82; 95% CI, 1.16-2.87) and low-volume center (OR = 1.48; 95% CI, 1.11-1.99). Cox regressions up to 90 months confirmed results. The hazard ratio was 1.97 (95% CI, 1.59-2.43) for D-MELD class C versus class B and 0.42 (95% CI, 0.29-0.60) for D-MELD class A versus class B. Recipient age, HCV, HBV and retransplant were also significant. The 5yrsPS<50% cutoff was identified only in HCV patients (D-MELD ≥ 1750). The innovative approach offered by D-MELD and covariates is helpful in predicting outcome after liver transplantation, especially in HCV recipients.

Cyclosporine a-based immunosuppression reduces relapse rate after antiviral therapy in transplanted patients with hepatitis C virus infection: a large multicenter cohort study

BACKGROUND

The influence of immunosuppression on the response to antiviral treatment in recurrent hepatitis C is still under debate. The purpose of this study was to identify those factors that might predict sustained viral response and relapse.

METHODS

The ReViS-TC, a multicenter cohort study conducted in 14 Spanish liver centers, included data from liver transplant recipients from January 2000 to December 2006 who had recurrent hepatitis C virus and who had undergone antiviral treatment with pegylated interferon plus ribavirin. Sustained virological response (SVR) and viral relapse were evaluated. A multivariate logistic regression model was used to investigate host, donor, and therapeutic factors associated with SVR and relapse.

RESULTS

The analysis included 410 patients, 30% treated with cyclosporine A (CsA) and 70% with tacrolimus. SVR was achieved in 48% of patients with CsA and in 37% with tacrolimus (P=0.037), with a relapse rate of 18% and 36%, respectively (P=0.008). In the multivariate model, the administration of CsA (odds ratio [OR] 0.37, P=0.021) in conjunction with a longer antiviral treatment duration (OR 0.86, P=0.024) correlated with lower relapse rate, whereas the older age of the donor (OR 1.03, P=0.006) and the presence of genotype 1 (OR 3.45, P=0.032) were associated with a higher probability of relapse.

CONCLUSIONS

Our results suggest that the use of CsA-based immunosuppression regimens and longer treatment duration may protect patients against viral relapse after a positive response to pegylated interferon plus ribavirin therapy. These data need to be further confirmed in clinical trials.

Long-term, maintenance MMF monotherapy improves the fibrosis progression in liver transplant recipients with recurrent hepatitis C

Hepatitis C virus (HCV) recurrence after orthotopic liver transplantation (LT) is universal. We designed a retrospective case-control study to evaluate the effect of mycophenolate mofetil (MMF) monotherapy in patients with recurrent hepatitis C. Fifteen patients with histologically proven hepatitis C recurrence after LT were switched from calcineurin inhibitors (CNIs) to MMF monotherapy because of impairment of kidney function and/or metabolic side effects, and treated for 48 months (MMF group). Fifteen well-matched LT recipients who continued to receive CNIs therapy over the same period served as control group. Demographics, clinical data, time after LT, and baseline liver biopsies were similar in the two groups. There was no worsening of hepatic fibrosis during the study in the MMF group [2.6 ± 1.5 (baseline) Ishak Units vs. 2.7 ± 1.8 (after 48 months of MMF treatment), P = 0.6]. In contrast, a significant increase in the fibrosis score [2 ± 1.1 (baseline) vs. 3.2 ± 1.7 (after 48 months of CNI treatment), P = 0.0002] was observed in the control group. The yearly fibrosis progression rate was of 0.05 ± 0.44 in the MMF group and 0.33 ± 0.24 in the CNI group (P = 0.04). MMF monotherapy is associated with a favourable effect on hepatic fibrosis progression in HCV liver transplant recipients.

Posttransplant biliary complications in the pre- and post-model for end-stage liver disease era

Biliary complications remain a cause of morbidity after liver transplantation. The aim of this study was to determine whether changes in clinical practice in the era of the Model for End-Stage Liver Disease (MELD) has affected biliary complications after liver transplantation. We retrospectively reviewed all deceased donor liver transplants at a single center. Patients were categorized as pre- or post-MELD (transplant before or after February 28, 2002). A total of 1798 recipients underwent deceased donor liver transplants. Biliary stricture was more common in the post-MELD era (15.4% versus 6.4%, P < 0.001). The strongest risk factors for stricture development were donor age (odds ratio [OR] = 1.01), presence of a prior bile leak (OR = 2.24), use of choledochocholedochostomy (OR = 2.22), and the post-MELD era (OR = 2.30). Bile leak was more common in the pre-MELD era (7.5% versus 4.9%, P = 0.02), with use of a T-tube as the strongest risk factor (OR = 3.38). Surgical factors did not influence the biliary complication rate. In conclusion, even when employing multivariate analysis to allow for factors that may influence biliary strictures, transplant in the post-MELD era was an independent predictor for stricture development. Further studies are warranted to determine the etiology of this increase.

Analysis of liver transplant outcomes for United Network for Organ Sharing recipients 60 years old or older identifies multiple model for end-stage liver disease-independent prognostic factors

Older recipient age is associated with worse posttransplant survival. Although the median age of liver disease patients undergoing orthotopic liver transplantation (OLT) continues to rise, prognostic factors for posttransplant survival specific to older patients have not been defined. To address this issue, the United Network for Organ Sharing/Organ Procurement and Transplantation Network outcome database was searched to identify prognostic factors for the 8070 liver recipients 60 years old or older who underwent transplantation from 1994 to 2005. Prognostic factors were assessed with univariate analysis and multivariate modeling. The 5 strongest prognostic variables (ventilator status, diabetes mellitus, hepatitis C virus, creatinine levels >/=1.6 mg/dL, and recipient and donor age >or=120 years) were aggregated to define a novel older recipient prognostic score (ORPS). The overall 1- and 5-year posttransplant survival rates were 83% and 67%, respectively. The risk model, created by the assignment of 1 point to each ORPS factor, stratified patient outcomes into distinct prognostic groups at the 1-, 3-, and 5-year posttransplant time points (P < 0.001). The 5-year survival rates for patients with ORPS values of 0, 1, and 2 points were 75%, 69%, and 58%, respectively. Patients who underwent transplantation with an ORPS > 2 points consistently experienced 5-year survival rates of less than 50%. In conclusion, in liver transplant recipients 60 years old or older, the ORPS was able to predict significant and clinically relevant differences in posttransplant survival. By optimization of donor selection for recipients over the age of 60 years, clinical utilization of the ORPS model may enhance organ utilization for all patients awaiting OLT.