The introduction of MELD-based organ allocation impacts 3-month survival after liver transplantation by influencing pretransplant patient characteristics

Development and validation of a practical machine learning model to predict sepsis after liver transplantation

BACKGROUND

Postoperative sepsis is one of the main causes of mortality after liver transplantation (LT). Our study aimed to develop and validate a predictive model for postoperative sepsis within 7 d in LT recipients using machine learning (ML) technology.

METHODS

Data of 786 patients received LT from January 2015 to January 2020 was retrospectively extracted from the big data platform of Third Affiliated Hospital of Sun Yat-sen University. Seven ML models were developed to predict postoperative sepsis. The area under the receiver-operating curve (AUC), sensitivity, specificity, accuracy, and f1-score were evaluated as the model performances. The model with the best performance was validated in an independent dataset involving 118 adult LT cases from February 2020 to April 2021. The postoperative sepsis-associated outcomes were also explored in the study.

RESULTS

After excluding 109 patients according to the exclusion criteria, 677 patients underwent LT were finally included in the analysis. Among them, 216 (31.9%) were diagnosed with sepsis after LT, which were related to more perioperative complications, increased postoperative hospital stay and mortality after LT (all p < .05). Our results revealed that a larger volume of red blood cell infusion, ascitic removal, blood loss and gastric drainage, less volume of crystalloid infusion and urine, longer anesthesia time, higher level of preoperative TBIL were the top 8 important variables contributing to the prediction of post-LT sepsis. The Random Forest Classifier (RF) model showed the best overall performance to predict sepsis after LT among the seven ML models developed in the study, with an AUC of 0.731, an accuracy of 71.6%, the sensitivity of 62.1%, and specificity of 76.1% in the internal validation set, and a comparable AUC of 0.755 in the external validation set.

CONCLUSIONS

Our study enrolled eight pre- and intra-operative variables to develop an RF-based predictive model of post-LT sepsis to assist clinical decision-making procedure.

Branched Chain Amino Acids Are Associated with Physical Performance in Patients with End-Stage Liver Disease

Decreased circulating branched chain amino acids (BCAA) represent a prominent change in amino acid profiles in patients with end-stage liver disease (ESLD). These alterations are considered to contribute to sarcopenia and hepatic encephalopathy and may relate to poor prognosis. Here, we cross-sectionally analyzed the association between plasma BCAA levels and the severity of ESLD and muscle function in participants of the liver transplant subgroup of TransplantLines, enrolled between January 2017 and January 2020. Plasma BCAA levels were measured by nuclear magnetic resonance spectroscopy. Physical performance was analyzed with a hand grip strength test, 4 m walking test, sit-to-stand test, timed up and go test, standing balance test and clinical frailty scale. We included 92 patients (65% men). The Child Pugh Turcotte classification was significantly higher in the lowest sex-stratified BCAA tertile compared to the highest tertile (p = 0.015). The times for the sit-to-stand (r = -0.352, p < 0.05) and timed up and go tests (r = -0.472, p < 0.01) were inversely correlated with total BCAA levels. In conclusion, lower circulating BCAA are associated with the severity of liver disease and impaired muscle function. This suggests that BCAA may represent a useful prognostic marker in the staging of liver disease severity.

MELD-GRAIL and MELD-GRAIL-Na Are Not Superior to MELD or MELD-Na in Predicting Liver Transplant Waiting List Mortality at a Single-center Level

Controversy exists regarding the best predictive model of liver transplant waiting list (WL) mortality. Models for end-stage liver disease–glomerular filtration rate assessment in liver disease (MELD-GRAIL) and MELD-GRAIL-Na were recently described to provide better prognostication, particularly in females. We evaluated the performance of these scores compared to MELD and MELD-Na.

A decline in functional status while awaiting liver transplantation is predictive of increased post-transplantation mortality

BACKGROUND

Functional status (FS) is dynamic and changes over time. We examined how changes in FS while awaiting liver transplantation influence post-transplant outcomes.

METHODS

Data on adult liver transplants performed in the United States during the MELD era were obtained through September 2020. Patient and graft survival were compared between groups with no change or improved FS, and those with worsening FS.

RESULTS

Of the 90,210 transplant recipients included in the analysis, 39,193 (43%) had worsening FS, which was associated with longer waiting-list time (187 vs. 329 days, p < 0.001) and worse patient survival after liver transplant (1858 vs. 1727 days, p < 0.001). A consistent and dose-dependent relationship was observed for each 10-point decrease in Karnofsky Performance Score and post-transplant survival. Multivariable regression analysis confirmed that a decline in FS was associated with worse patient survival (HR 1.15, p < 0.001). Similar findings were observed for graft survival.

CONCLUSION

A decline in FS on the waiting-list is associated with significantly greater post-liver transplant mortality in recipients. These results should be taken into consideration when allocating organs and determining transplant candidacy. Strategies to optimize FS prior to transplantation should be prioritized as even subtle decreases in FS are associated with inferior post-transplantation outcomes.

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

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

Early postoperative mortality in liver transplant recipients involving indications other than hepatocellular carcinoma. A retrospective cohort study

AIMS

To analyze the perioperative differences in a consecutive cohort of liver transplant recipients (LTRs) classified according to the indication of transplantation, and assess their impact upon early mortality 90 days after transplantation.

DESIGN

A retrospective cohort study was carried out.

SCOPE

A single university hospital.

PATIENTS

A total of 892 consecutive adult LTRs were included from January 1995 to December 2017. Recipients with acute liver failure, retransplantation or with grafts from non-brain death donors were excluded. Two cohorts were analyzed according to transplant indication: hepatocellular carcinoma (HCC-LTR) versus non-carcinoma (non-HCC-LTR).

MAIN VARIABLES OF INTEREST

Recipient early mortality was the primary endpoint. The pretransplant recipient and donor characteristics, surgical time data and postoperative complications were analyzed as independent predictors.

RESULTS

The crude early postoperative mortality rate related to transplant indication was 13.3% in non-HCC-LTR and 6.6% in HCC-LTR (non-adjusted HR=2.12, 95%CI=1.25-3.60; p=0.005). Comparison of the perioperative features between the cohorts revealed multiple differences. Multivariate analysis showed postoperative shock (HR=2.02, 95%CI=1.26-3.24; p=0.003), early graft vascular complications (HR=4.01, 95%CI=2.45-6.56; p<0.001) and multiorgan dysfunction syndrome (HR=18.09, 95%CI=10.70-30.58; p<0.001) to be independent predictors of mortality. There were no differences in early mortality related to transplant indication (adjusted HR=1.60, 95%CI=0.93-2.76; p=0.086).

CONCLUSIONS

The crude early postoperative mortality rate in non-HCC-LTR was higher than in HCC-LTR, due to a greater incidence of postoperative complications with an impact upon mortality (shock at admission to intensive care and the development of multiorgan dysfunction syndrome).

Hospital Mortality and Current Trends in Liver Transplantation in Germany—a Systematic Analysis of Standardized Hospital Discharge Data, 2008–2017

BACKGROUND

Liver transplantation (LT) has undergone dynamic developments in recent decades. In Germany, the Federal Joint Committee (G-BA) recently tightened the guidelines regarding the minimum number of transplantations a center should perform annually. The aim of the study presented here, was to analyze recent trends in hospital mortality due to LT in Germany.

METHODS

Standardized hospital discharge data (2008-2017) from the Federal Statistical Office of Germany were used to establish hospital mortality after LT and case volume distribution among centers performing <20 LT annually (low volume centers, LVC), 20-49 LT (medium volume centers, MVC), and ≥ 50 LT (high volume centers, HVC).

RESULTS

Data from 9254 LT procedures were evaluated. The annual frequency of LT fell from n = 984 (2008) to n = 747 (2017), and over the same period the hospital mortality for all LT procedures went down from 15.8% to 11.0%. Hospital mortality was associated with age (<16 years: 5.3% to 60-69 years: 17.4%); however, there was no further increase in patients ≥ 70 years (16.5%). Univariate analysis revealed association of increased hospital mortality with liver disease etiology, the necessity for relaparotomy, and prolonged mechanical ventilation. The proportion of LT procedures performed in LVC and MVC increased and that in HVC decreased. LVC had higher hospital mortality than MVC/HVC, but this effect was dependent on patient age and disease etiology.

CONCLUSION

Our study showed that differences in mortality rate after LT among centers (LVC vs. MVC/HVC) were dependent on patient age and disease etiology. This should be taken into account when discussing the overall organization of LT in Germany.

Women who undergo liver transplant have longer length of stay post-transplant compared with men

BACKGROUND

Women on the liver transplant waitlist are at greater risk of hospitalization compared with men, but whether this impacts length of stay (LOS) post-transplant is unknown. We aimed to evaluate gender disparities in post-transplant LOS, an important surrogate of health resource utilization post-transplant.

METHODS

Using the UNOS/OPTN registry, we analysed all non-Status 1 adult deceased donor liver transplant recipients without exception points from 2008 to 2017. Poisson regression associated female gender with post-transplant LOS.

RESULTS

Of 27 294 transplant recipients, 36% were women. Women were more likely to be hospitalized pretransplant than men (44% vs 39%, P < .01). Post-transplant, women were more likely to have prolonged (≥20d) LOS (25% vs 22%, P < .01). In univariable analysis, female gender was associated with longer post-transplant LOS (IRR 1.09, 95%CI 1.06-1.12, P < .01). Prolonged pretransplant admission was also associated with post-transplant LOS (IRR 1.83, 95%CI 1.77-1.89, P < .01). In multivariable analysis, female gender remained independently associated with post-transplant LOS (aIRR 1.05, 95%CI 1.02-1.08, P < .01), after adjustment for age, UNOS region, insurance type, MELDNa, cirrhosis complications, and donor risk index. Pretransplant hospitalization mediated this relationship, explaining 14.1% (95%CI 9.7%-25.4%) of the total effect.

CONCLUSIONS

Women who undergo deceased donor liver transplant have increased healthcare utilization in the peritransplant period compared with men. Reducing gender disparities in liver transplantation, including the disproportionate burden of healthcare utilization by women pre- and post-transplant, will require interventions targeted at preventing hospitalization among women on the transplant waitlist and developing tools aimed at better characterizing the severity of end-stage liver disease in women.

The Effects of MELD-Based Liver Allocation on Patient Survival and Waiting List Mortality in a Country with a Low Donation Rate

The Model for End-Stage Liver Disease (MELD)-based allocation system was implemented in Germany in 2006 in order to reduce waiting list mortality. The purpose of this study was to evaluate post-transplant results and waiting list mortality since the introduction of MELD-based allocation in our center and in Germany. Adult liver transplantation at the Charité—Universitätsmedizin Berlin was assessed retrospectively between 2005 and 2012. In addition, open access data from Eurotransplant (ET) and the German Organ Transplantation Foundation (DSO) were evaluated. In our department, 861 liver transplantations were performed from 2005 to 2012. The mean MELD score calculated with the laboratory values last transmitted to ET before organ offer (labMELD) at time of transplantation increased to 20.1 from 15.8 (Pearson’s R = 0.121, p < 0.001, confidence interval (CI) = 0.053–0.187). Simultaneously, the number of transplantations per year decreased from 139 in 2005 to 68 in 2012. In order to overcome this organ shortage the relative number of utilized liver donors in Germany has increased (85% versus 75% in non-German ET countries). Concomitantly, 5-year patient survival decreased from 79.9% in 2005 to 60.3% in 2012 (p = 0.048). At the same time, the ratio of waiting list mortality vs. active-listed patients nearly doubled in Germany (Spearman’s rho = 0.903, p < 0.001, CI = 0.634–0.977). In low-donation areas, MELD-based liver allocation may require reconsideration and inclusion of prognostic outcome factors.

Impact of Model for End-stage Liver Disease Score-based Allocation System in Korea: A Nationwide Study

BACKGROUND

In June 2016, the Korean Network for Organ Sharing implemented a Model for End-stage Liver Disease (MELD) score-based allocation system to better prioritize deceased-donor liver transplant (DDLT) candidates. The aim of this study was to assess the impact of this allocation system.

METHODS

We compared waiting list and posttransplant outcomes during the first year of operation of the MELD allocation system (from June 2016 to May 2017) with an equivalent period before its implementation (from June 2015 to May 2016).

RESULTS

A total of 3041 candidates were listed for DDLT (1464 pre-MELD, 1577 post-MELD era) and 892 patients received DDLT during the study period. A decrease in waiting list mortality and an increase in DDLT rate were observed after MELD implementation. However, the number of living donor liver transplants did not differ significantly pre- to post-MELD. As was expected, introduction of the MELD allocation system increased mean MELD scores at DDLT (24.1 ± 8.3 pre-MELD, 34.5 ± 7.0 post-MELD era, P < 0.001). Posttransplant patient survival rates at 1-year were 79.9% in pre-MELD era and 76.2% in post-MELD era (P = 0.184). The proportion of interregional organ transfer increased from 25.1% to 40.5%. Furthermore, transplant benefits increased with MELD scores.

CONCLUSIONS

The MELD system was found to address the goal of fairness well. Implementation of the MELD system improved equity in terms of access to DDLT regardless of regions. Although a greater proportion of more severely ill patients received DDLT after MELD implementation, posttransplant survivals remained unchanged.

Benefits of N-acetylcysteine on liver functions in living donor hepatectomy

Background and Aims:

The proportion of patients undergoing living donor liver transplantation is high especially in countries without or with limited cadaver organ sharing programs. The aim of this study was to evaluate the post-hepatectomy effect of using N-Acetylcysteine (NAC) infusion in living donors undergoing donor hepatectomy.

Methods:

In a prospective randomised non-blinded study, 50 healthy donors were enrolled; following hepatectomy patients were randomised into 2 groups: Group NC receiving NAC 150 mg/kg diluted in 100 ml glucose 5% over 40 minutes, followed by NAC 12.5 mg/kg in 500 ml glucose 5% over 4 hours. This was followed by NAC 6.25 mg/kg for 2 post-operative days, Group C (Control group) received ringer acetate infusion at same rate for 2 days. The primary outcome was serum lactate levels. Secondary outcomes were liver function tests, serum creatinine and urine output on intensive care unit (ICU) admission (0 hr.), after 24 hours and 48 hours, length of ICU stay.

Results:

Our study revealed significant reduction in serum lactate in Group NC at 0, 24 and 48 hours compared to C group (P = 0.017, 0.002, 0.014). INR values showed significant reduction after 48 hours in Group NC compared to Group C (P = 0.049). Total Bilirubin, ALT, and Creatinine, urine output and ICU stay showed no statistical difference between the 2 groups.

Conclusion:

The NAC protocol is a safe, cost-effective tool for improvement of post hepatectomy liver function and early stabilisation of the metabolic profile.

Predicting Short-term Survival after Liver Transplantation using Machine Learning

Liver transplantation is one of the most effective treatments for end-stage liver disease, but the demand for livers is much higher than the available donor livers. Model for End-stage Liver Disease (MELD) score is a commonly used approach to prioritize patients, but previous studies have indicated that MELD score may fail to predict well for the postoperative patients. This work proposes to use data-driven approach to devise a predictive model to predict postoperative survival within 30 days based on patient’s preoperative physiological measurement values. We use random forest (RF) to select important features, including clinically used features and new features discovered from physiological measurement values. Moreover, we propose a new imputation method to deal with the problem of missing values and the results show that it outperforms the other alternatives. In the predictive model, we use patients’ blood test data within 1–9 days before surgery to construct the model to predict postoperative patients’ survival. The experimental results on a real data set indicate that RF outperforms the other alternatives. The experimental results on the temporal validation set show that our proposed model achieves area under the curve (AUC) of 0.771 and specificity of 0.815, showing superior discrimination power in predicting postoperative survival.

Allocation of liver grafts worldwide - Is there a best system?

BACKGROUND & AIMS

An optimal allocation system for scarce resources should simultaneously ensure maximal utility, but also equity. The most frequent principles for allocation policies in liver transplantation are therefore criteria that rely on pre-transplant survival (sickest first policy), post-transplant survival (utility), or on their combination (benefit). However, large differences exist between centers and countries for ethical and legislative reasons. The aim of this study was to report the current worldwide practice of liver graft allocation and discuss respective advantages and disadvantages.

METHODS

Countries around the world that perform 95 or more deceased donor liver transplantations per year were analyzed for donation and allocation policies, as well as recipient characteristics.

RESULTS

Most countries use the model for end-stage liver disease (MELD) score, or variations of it, for organ allocation, while some countries opt for center-based allocation systems based on their specific requirements, and some countries combine both a MELD and center-based approach. Both the MELD and center-specific allocation systems have inherent limitations. For example, most countries or allocation systems address the limitations of the MELD system by adding extra points to recipient's laboratory scores based on clinical information. It is also clear from this study that cancer, as an indication for liver transplantation, requires special attention.

CONCLUSION

The sickest first policy is the most reasonable basis for the allocation of liver grafts. While MELD is currently the standard for this model, many adjustments were implemented in most countries. A future globally applicable strategy should combine donor and recipient factors, predicting probability of death on the waiting list, post-transplant survival and morbidity, and perhaps costs.

LAY SUMMARY

An optimal allocation system for scarce resources should simultaneously ensure maximal utility, but also equity. While the model for end-stage liver disease is currently the standard for this model, many adjustments were implemented in most countries. A future globally applicable strategy should combine donor and recipient factors predicting probability of death on the waiting list, post-transplant survival and morbidity, and perhaps costs.

Development of a Korean Liver Allocation System using Model for End Stage Liver Disease Scores: A Nationwide, Multicenter study

The previous Korean liver allocation system was based on Child-Turcotte-Pugh scores, but increasing numbers of deceased donors created a pressing need to develop an equitable, objective allocation system based on model for end-stage liver disease scores (MELD scores). A nationwide, multicenter, retrospective cohort study of candidates registered for liver transplantation from January 2009 to December 2011 was conducted at 11 transplant centers. Classification and regression tree (CART) analysis was used to stratify MELD score ranges according to waitlist survival. Of the 2702 patients that registered for liver transplantation, 2248 chronic liver disease patients were eligible. CART analysis indicated several MELD scores significantly predicted waitlist survival. The 90-day waitlist survival rates of patients with MELD scores of 31-40, 21-30, and ≤20 were 16.2%, 64.1%, and 95.9%, respectively (P < 0.001). Furthermore, the 14-day waitlist survival rates of severely ill patients (MELD 31-40, n = 240) with MELD scores of 31-37 (n = 140) and 38-40 (n = 100) were 64% and 43.4%, respectively (P = 0.001). Among patients with MELD > 20, presence of HCC did not affect waitlist survival (P = 0.405). Considering the lack of donor organs and geographic disparities in Korea, we proposed the use of a national broader sharing of liver for the sickest patients (MELD ≥ 38) to reduce waitlist mortality. HCC patients with MELD ≤ 20 need additional MELD points to allow them equitable access to transplantation. Based on these results, the Korean Network for Organ Sharing implemented the MELD allocation system in 2016.

Impact of the new MELD-based allocation system on waiting list and post-transplant survival - a cohort analysis using the French national CRISTAL database

Concerns related to equity and efficacy of our previous center-based allocation system have led us to introduce a patient-based allocation system called the "Liver Score" that incorporates the MELD score. The main objective of this study was to compare waitlist and post-transplant survivals before and after implementation of the "Liver Score" using the French transplant registry (period before: 2004-2006 and period after: 2007-2012). Patients transplanted during the second period were sicker and had a higher MELD. One-year waitlist survival (74% versus 76%; p=0.8) and one-year post-transplant survival (86.3% vs 85.7%; p=0.5) were similar between the 2 periods. Cirrhotic recipients with MELD>35 had lower one-year post-transplant survival compared to those with MELD<35 (74.8% vs 86.3%; p<0.01), mainly explained by their higher intubation and renal failure rates. The MELD showed a poor discriminative capacity. In cirrhotic recipients with MELD>35, patients presenting 2 or 3 risk factors (dialysis, intubation or infection) had a lower 1-year survival compared to those with none of these risk factors (61.2% vs 92%; p<0.01). The implementation of the MELD-based allocation system has led to transplant sicker patients with no impact on waitlist and post-transplant survivals. Nevertheless, selection of patients with MELD>35 should be completed to allow safe transplantation. This article is protected by copyright. All rights reserved.

Risk Factors for High Mortality on the Liver Transplant Waiting List in Times of Organ Shortage: A Single-Center Analysis

BACKGROUND Germany has the highest rate of patients dying or becoming unfit for transplant while waitlisted within the Eurotransplant region. Therefore, the aim of the current study was to analyze mortality as well as risk factors for mortality of candidates listed for liver transplantation at our center. MATERIAL AND METHODS Between 01/2011 and 12/2013, 481 adult patients were listed for primary liver transplantation (LT) at a single German center. Clinical and laboratory parameters were prospectively collected and retrospectively analyzed by univariable and multivariable logistic regression and Cox proportional hazards. RESULTS The mean model for end-stage liver disease (MELD) score of all liver transplant waitlist registrants (52.4 years, 60.1% male) was 16.9 (±10.2) at time of listing, with 10% of the listed patients having a MELD score of >32. After waitlisting, 133 (27.7%) candidates died within the follow-up period. Three-month-survival after listing for transplantation was 89% for patients ultimately receiving LT vs. 71.2% that did not receive LT (p<0.001). Multivariable analysis identified clinical parameters such as ICU treatment, preceding abdominal surgery, variceal bleeding, and ascites, as well as hydropic decompensation, as independent risk factors for waitlist mortality. CONCLUSIONS Consideration of independent risk factors of mortality within the MELD-based allocation system potentially improves assessment of individual urgency and might improve utilization of available organs.

Waitlist mortality and post-transplant survival in patients with cholestatic liver disease - Impact of changes in allocation policy

BACKGROUND

This study investigated the impact of Model of end-stage liver disease (MELD)-score introduction (MELDi) on waitlist mortality and post-liver transplant (LT) survival in primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC).

METHODS

LT candidates with PSC or PBC listed between January 1983 and March 2016 were included and followed until December 2016. After MELDi in 2004, PBC patients were listed according to labMELD, PSC patients according to the highest MELD during active cholangitis (chMELD).

RESULTS

In total, 100 PBC and 76 PSC patients were included. Waitlist mortality in PBC was significantly higher than in PSC (16% vs. 5.3%, p = 0.031), whereas PSC patients were significantly more often withdrawn from the waitlist due to improved condition (3.0% vs. 13.2%, p = 0.017). Competing risks analysis identified MELDi (HR = 4.12) and PBC (HR = 2.95) as significant predictors of waitlist mortality. Yet, overall 10 y-patient survival increased after MELDi by 18.8% leading to a 1 y-, 5 y-, and 10 y-patient survival of 98.2%, 70.6% and 70.6% in PBC, and 83.3%, 83.3%, and 80.6% in PSC, respectively.

CONCLUSIONS

PSC patients showed significantly lower waitlist mortality irrespective of MELDi, whereas in PBC waitlist mortality further increased after MELDi. Utility of MELD and chMELD did not impair post LT outcome.

The impact of major extended donor criteria on graft failure and patient mortality after liver transplantation

INTRODUCTION

Numerous extended donor criteria (EDC) have been identified in liver transplantation (LT), but different EDC have different impacts on graft and patient survival. This study aimed to identify major EDC (maEDC) that were best able to predict the outcome after LT and to examine the plausibility of an allocation algorithm based on these criteria.

METHODS

All consecutive LTs between 12/2006 and 03/2014 were included (n = 611). We analyzed the following EDC: donor age > 65 years, body mass index > 30, malignancy and drug abuse history, intensive care unit stay/ventilation > 7 days, aminotransferases > 3 times normal, serum bilirubin > 3 mg/dL, serum Na⁺ > 165 mmol/L, positive hepatitis serology, biopsy-proven macrovesicular steatosis (BPS) > 40%, and cold ischemia time (CIT) > 14 h. We analyzed hazard risk ratios of graft failure for each EDC and evaluated primary non-function (PNF). In addition, we analyzed 30-day, 90-day, 1-year, and 3-year graft survival. We established low- and high-risk graft (maEDC 0 vs. ≥ 1) and recipient (labMELD < 20 vs. ≥ 20) groups and compared the post-LT outcomes between these groups.

RESULTS

BPS > 40%, donor age > 65 years, and CIT > 14 h (all p < 0.05) were independent predictors of graft failure and patient mortality and increased PNF, 30-day, 90-day, 1-year, and 3-year graft failure rates. Three-year graft and patient survival decreased in recipients of ≥ 1 maEDC grafts (all p < 0.05) and LT of high-risk grafts into high-risk recipients yielded worse outcomes compared with other groups.

CONCLUSION

Donor age > 65 years, BPS > 40%, and CIT > 14 h are major EDC that decrease short and 3-year graft survival, and 3-year patient survival. An allocation algorithm based on maEDC and labMELD is therefore plausible.

Functional status, healthcare utilization, and the costs of liver transplantation

The Model for End-Stage Liver Disease (MELD) score predicts higher transplant healthcare utilization and costs; however, the independent contribution of functional status towards costs is understudied. The study objective was to evaluate the association between functional status, as measured by Karnofsky Performance Status (KPS), and liver transplant (LT) costs in the first posttransplant year. In a cohort of 598 LT recipients from July 1, 2009 to November 30, 2014, multivariable models assessed associations between KPS and outcomes. LT recipients needing full assistance (KPS 10%-40%) vs being independent (KPS 80%-100%) were more likely to be discharged to a rehabilitation facility after LT (22% vs 3%) and be rehospitalized within the first posttransplant year (78% vs 57%), all P < .001. In adjusted generalized linear models, in addition to MELD (P < .001), factors independently associated with higher 1-year post-LT transplant costs were older age, poor functional status (KPS 10%-40%), living donor LT, pre-LT hemodialysis, and the donor risk index (all P < .001). One-year survival for patients in the top cost decile was 83% vs 93% for the rest of the cohort (log rank P < .001). Functional status is an important determinant of posttransplant resource utilization; therefore, standardized measurements of functional status should be considered to optimize candidate selection and outcomes.

New concepts in acute-on-chronic liver failure: Implications for liver transplantation

Acute-on-chronic liver failure (ACLF) is a recently defined syndrome that occurs frequently in patients with cirrhosis and is associated with a poor short-term prognosis. Currently, management of patients with ACLF is mainly supportive. Despite medical progress, this syndrome frequently leads to multiorgan failure, sepsis, and, ultimately, death. The results of attempts to use liver transplantation (LT) to manage this critical condition have been poorly reported but are promising. Currently, selection criteria of ACLF patients for LT, instructions for prioritization on the waiting list, and objective indicators for removal of ACLF patients from the waiting list in cases of clinical deterioration are poorly defined. Before potential changes can be implemented into decisional algorithms, their effects, either on the benefits to individual patients or on global transplant outcomes, should be carefully evaluated using objective longterm endpoints that take into account ethical considerations concerning LT. Liver Transplantation 23 234-243 2017 AASLD.

Biliary complications following liver transplantation: Single-center experience over three decades and recent risk factors

AIM

To identify independent risk factors for biliary complications in a center with three decades of experience in liver transplantation.

METHODS

A total of 1607 consecutive liver transplantations were analyzed in a retrospective study. Detailed subset analysis was performed in 417 patients, which have been transplanted since the introduction of Model of End-Stage Liver Disease (MELD)-based liver allocation. Risk factors for the onset of anastomotic biliary complications were identified with multivariable binary logistic regression analyses. The identified risk factors in regression analyses were compiled into a prognostic model. The applicability was evaluated with receiver operating characteristic curve analyses. Furthermore, Kaplan-Meier analyses with the log rank test were applied where appropriate.

RESULTS

Biliary complications were observed in 227 cases (14.1%). Four hundred and seventeen (26%) transplantations were performed after the introduction of MELD-based donor organ allocation. Since then, 21% (n = 89) of the patients suffered from biliary complications, which are further categorized into anastomotic bile leaks [46% (n = 41)], anastomotic strictures [25% (n = 22)], cholangitis [8% (n = 7)] and non-anastomotic strictures [3% (n = 3)]. The remaining 18% (n = 16) were not further classified. After adjustment for all univariably significant variables, the recipient MELD-score at transplantation (P = 0.006; OR = 1.035; 95%CI: 1.010-1.060), the development of hepatic artery thrombosis post-operatively (P = 0.019; OR = 3.543; 95%CI: 1.233-10.178), as well as the donor creatinine prior to explantation (P = 0.010; OR = 1.003; 95%CI: 1.001-1.006) were revealed as independent risk factors for biliary complications. The compilation of these identified risk factors into a prognostic model was shown to have good prognostic abilities in the investigated cohort with an area under the receiver operating curve of 0.702.

CONCLUSION

The parallel occurrence of high recipient MELD and impaired donor kidney function should be avoided. Risk is especially increased when post-transplant hepatic artery thrombosis occurs.

[Acute Kidney Injury in Cirrhotic Patients with Portal Hypertension]

Acute kidney injury (AKI) is one of the most common manifestations encountered in clinical practice. It is associated with high morbidity and mortality in cirrhotic pre- and post-transplantation patients. Hepatorenal syndrome (HRS), a special form of AKI in cirrhotic patients, was recognized as a consequence of renal vasoconstriction from systemic/renal hemodynamic alterations developed in advanced cirrhosis with portal hypertension. Recently, multiple factors-such as infection/inflammation, underlying glomerulonephritis, bile cast, or increased abdominal pressure-have been considered to contribute to renal dysfunction in cirrhotic patients, which were presumed to induce HRS. Moreover, in addition to changing the definition of AKI in the nephrologic guidelines, the new AKI definition for early diagnosis and intervention based on characteristics of liver cirrhosis has been proposed in an international meeting. This article provides a comprehensive and recent review of AKI definition, laying out the topics in accordance with the pathophysiologic mechanisms and therapeutic interventions of AKI in cirrhotic patients with portal hypertension.

Predictive factors of short term outcome after liver transplantation: A review

Liver transplantation represents a fundamental therapeutic solution to end-stage liver disease. The need for liver allografts has extended the set of criteria for organ acceptability, increasing the risk of adverse outcomes. Little is known about the early postoperative parameters that can be used as valid predictive indices for early graft function, retransplantation or surgical reintervention, secondary complications, long intensive care unit stay or death. In this review, we present state-of-the-art knowledge regarding the early post-transplantation tests and scores that can be applied during the first postoperative week to predict liver allograft function and patient outcome, thereby guiding the therapeutic and surgical decisions of the medical staff. Post-transplant clinical and biochemical assessment of patients through laboratory tests (platelet count, transaminase and bilirubin levels, INR, factor V, lactates, and Insulin Growth Factor 1) and scores (model for end-stage liver disease, acute physiology and chronic health evaluation, sequential organ failure assessment and model of early allograft function) have been reported to have good performance, but they only allow late evaluation of patient status and graft function, requiring days to be quantified. The indocyanine green plasma disappearance rate has long been used as a liver function assessment technique and has produced interesting, although not univocal, results when performed between the 1^th and the 5^th day after transplantation. The liver maximal function capacity test is a promising method of metabolic liver activity assessment, but its use is limited by economic cost and extrahepatic factors. To date, a consensual definition of early allograft dysfunction and the integration and validation of the above-mentioned techniques, through the development of numerically consistent multicentric prospective randomised trials, are necessary. The medical and surgical management of transplanted patients could be greatly improved by using clinically reliable tools to predict early graft function.

Plasma Amino Acid Concentrations Predict Mortality in Patients with End-Stage Liver Disease

BACKGROUND

The liver plays a key role in amino acid metabolism. In former studies, a ratio between branched-chain and aromatic amino acids (Fischer's ratio) revealed associations with hepatic encephalopathy. Furthermore, low concentrations of branched-chain amino acids were linked to sarcopenia in literature. Encephalopathy and sarcopenia are known to dramatically worsen the prognosis. Aim of this study was to investigate a complex panel of plasma amino acids in the context of mortality in patients with end-stage liver disease.

METHODS

166 patients evaluated for orthotopic liver transplantation were included. 19 amino acids were measured from citrated plasma samples using mass spectrometry. We performed survival analysis for plasma amino acid constellations and examined the relationship to established mortality predictors.

RESULTS

33/166 (19.9%) patients died during follow-up. Lower values of valine (p<0.001), Fischer's ratio (p<0.001) and valine to phenylalanine ratio (p<0.001) and higher values of phenylalanine (p<0.05) and tyrosine (p<0.05) were significantly associated with mortality. When divided in three groups, the tertiles discriminated cumulative survival for valine (p = 0.016), phenylalanine (p = 0.024) and in particular for valine to phenylalanine ratio (p = 0.003) and Fischer's ratio (p = 0.005). Parameters were also significantly correlated with MELD and MELD-Na score.

CONCLUSIONS

Amino acids in plasma are valuable biomarkers to determine increased risk of mortality in patients with end-stage liver disease. In particular, valine concentrations and constellations composed of branched-chain and aromatic amino acids were strongly associated with prognosis. Due to their pathophysiological importance, the identified amino acids could be used to examine individual dietary recommendations to serve as potential therapeutic targets.

HCC-Associated Liver Transplantation - Where Are the Limits and What Are the New Regulations?

BACKGROUND

Hepatocellular carcinoma (HCC) represents an increasing health burden worldwide and a challenging disease both in terms of diagnosis and treatment.

METHODS

The literature available on PubMed for the period of 1990-2016 was reviewed with reference to liver allocation, HCC, liver transplantation (LT), and prediction, and the allocation rules of the German Transplant Act were reviewed.

RESULTS

Due to etiological and geographical diversity, HCC is not a homogeneous disease. In the vast majority of patients, HCC develops as a complication of chronic liver disease and cirrhosis. While most patients present with advanced HCC for which palliative strategies are the only available option, LT is the best treatment approach as it not only eliminates the diseased liver and the underlying hepatocarcinogenic mechanisms but also the cancer. The decision for LT is not an easy one to make, because outcome prediction, staging, bridging therapy, and recurrence prevention are difficult and are estimated against the background of the scarce resource of donor organs which are also competitively sought after by patients suffering from non-neoplastic terminal liver diseases, raising the issue of equality of chances in a rationed therapeutic modality. Currently, the Milan criteria are the best evaluated decision tool for LT, but many issues such as down-staging, favorable biological behavior during treatment, expansion of the morphological classification, molecular predictors, and individualized approaches are not yet satisfactorily addressed.

CONCLUSION

In order to provide a fair and effective approach to LT in HCC, the employed allocation rules require continuous development and scientific evaluation. Recently, the allocation rules for standard exception priority according to the German Transplant Act have been revised to improve patient selection for LT in HCC.

The new liver allocation score for transplantation is validated and improved transplant survival benefit in Germany but not in the United Kingdom

Prognostic models for the prediction of 90-day mortality after transplantation with pretransplant donor and recipient variables are needed to calculate transplant benefit. Transplants in adult recipients in Germany (Hannover, n = 770; Kiel, n = 234) and the United Kingdom (Birmingham, n = 829) were used for prognostic model design and validation in separate training and validation cohorts. The survival benefit of transplantation was estimated by subtracting the observed posttransplant 90-day mortality from the expected 90-day mortality without transplantation determined by the Model for End-Stage Liver Disease (MELD) score. A prognostic model called the liver allocation score (LivAS) was derived using a randomized sample from Hannover using pretransplant donor and recipient variables. This model could be validated in the German training and validation cohorts (area under the receiver operating characteristic curve [AUROC] > 0.70) but not in the English cohort (AUROC, 0.58). Although 90-day mortality rates after transplantation were 13.7% in Hannover, 12.1% in Kiel, and 8.3% in Birmingham, the calculated 90-day survival benefits of transplantation were 6.8% in Hannover, 7.8% in Kiel, and 2.8% in Birmingham. Deployment of the LivAS for limiting allocation to donor and recipient combinations with likely 90-day survival as indicated by pretransplant LivAS values below the cutoff value would have increased the survival benefit to 12.9% in the German cohorts, whereas this would have decreased the benefit in England to 1.3%. The English and German cohorts revealed significant differences in 21 of 28 pretransplant variables. In conclusion, the LivAS could be validated in Germany and may improve German allocation policies leading to greater survival benefits, whereas validation failed in England due to profound differences in the selection criteria for liver transplantation. This study suggests the need for national prognostic models. Even though the German centers had higher rates of 90-day mortality, estimated survival benefits were greater. Liver Transplantation 22 743-756 2016 AASLD.

Who is too healthy and who is too sick for liver transplantation: external validation of prognostic scores and survival-benefit estimation

OBJECTIVE

Thresholds for when a patient should be considered too healthy or too sick to undergo liver transplantation (LT) have been pursued, but have undergone little external validation and may differ between centers and countries.

MATERIAL AND METHODS

We investigated the ability of the Model for End-stage Liver Disease (MELD), D-MELD, Donor Risk Index (DRI) and Balance of Risk (BAR) scores to predict 1-year graft survival, and determined the 1-year survival-benefit of LT, compared with conservative management, according to MELD score and graft quality among 538 adult LT recipients with underlying chronic non-malignant liver disease.

RESULTS

One-year graft survival rates showed small, but statistically significant variation according to MELD (p = 0.002) and D-MELD score (p = 0.04), and among LTs after year 2000 also according to BAR score (p = 0.01), but not according to DRI. Diagnostic accuracy of these scores was poor; area under the curve was 0.50-0.65 depending on the score. A 1-year survival-benefit of LT emerged at MELD scores ≥15, but also at lower MELD scores when using high-quality grafts (DRI <1.075).

CONCLUSIONS

The performance of various prognostic scores in the Finnish setting was poor. Careful clinical evaluation is imperative when deciding on the timing of LT in the course of chronic liver disease.

[Allocation systems in transplantation medicine: Advantages and disadvantages]

Donor organs for transplantations are a scarce commodity; therefore, allocation systems are needed that guarantee an ethically acceptable distribution to patients on the waiting list (equal treatment and fairness) but also take the probability of survival of the transplant in each recipient into consideration. In this article the allocation systems for lung, liver, kidney and pancreas transplants are presented.For lung transplantations an allocation system based on the lung allocation score (LAS) is currently used. The LAS predicts the probability of survival on the waiting list and the survival rate following transplantation. Organs with a limited range of utilization are distributed in a so-called mini-match procedure.For post-mortem kidney and pancreas transplantations a relatively complex but transparent allocation system has been created in which patients are subdivided into groups, each of which has its own allocation rules. The allocation is principally carried out according to criteria of fairness of distribution and according to the prospects of success. The probability of a mismatch also plays a role. The urgency is important for children and for patients who do not have the possibility of dialysis. Combined pancreas and kidney transplantations have priority over kidney transplantations alone.The criterion for the urgency of liver transplantation in Germany is currently the model for end-stage liver disease (MELD), which aims to reduce the waiting list mortality and to prioritize transplantations for those most in need. Because the system insufficiently describes the priority of transplantation for patients with tumors or genetic liver diseases, there is an additional set of rules for so-called standard exceptions.

Early post-transplant survival: Interaction of MELD score and hospitalization status

BACKGROUND & AIMS

Urgency-based allocation that relies on the MELD score prioritizes patients at the highest risk of waitlist mortality. However, identifying patients at greatest risk for short-term post-transplant mortality is needed in order to optimize the potential gains in overall survival obtained through improved long-term management of transplant recipients. There are limited data on the predictive ability of MELD score for early post-transplant mortality, and no data assessing the interaction between MELD score and hospitalization status.

METHODS

We analyzed UNOS data from 2002 to 2013 on 50,838 non-status 1 single-organ liver transplant recipients and fit multivariable logistic models to evaluate the association and interaction between MELD score and pre-transplant hospitalization status on short-term post-transplant mortality.

RESULTS

There was a significant interaction (p<0.01) between laboratory MELD score and hospitalization status on three-, six-, and 12-month post-transplant mortality in multivariable logistic models. This interaction was most pronounced in patients with a laboratory MELD score <25 transplanted from an ICU, whose adjusted predicted three-, six-, and 12-month post-transplant mortality approximated those of patients with a MELD score ⩾30. Compared to hospitalized patients with a MELD score of 30-34, those with a MELD score ⩾35 in an ICU had significantly increased risk of three-month (OR: 1.54, 95% CI: 1.21-1.97), 6-month (OR: 1.35, 95% CI: 1.09-1.67), and 12-month (OR: 1.25, 95% CI: 1.03-1.52) post-transplant mortality.

DISCUSSION

Pre-transplant ICU status modifies the risk of early post-transplant mortality, independent of MELD score. This should be considered when determining candidacy for transplantation in order to optimize efficient use of a scarce resource.

Evaluating the efficacy, safety and evolution of renal function with early initiation of everolimus-facilitated tacrolimus reduction in de novo liver transplant recipients: Study protocol for a randomized controlled trial

BACKGROUND

Introduction of calcineurin inhibitors had led to improved survival rates in liver transplant recipients. However, long-term use of calcineurin inhibitors is associated with a higher risk of chronic renal failure, neurotoxicity, de novo malignancies, recurrence of hepatitis C viral (HCV) infection and hepatocellular carcinoma. Several studies have shown that everolimus has the potential to provide protection against viral replication, malignancy, and progression of fibrosis, as well as preventing nephrotoxicity by facilitating calcineurin inhibitor reduction without compromising efficacy. The Hephaistos study evaluates the beneficial effects of early initiation of everolimus in de novo liver transplant recipients.

METHODS/DESIGN

Hephaistos is an ongoing 12-month, multi-center, open-label, controlled study aiming to enroll 330 de novo liver transplant recipients from 15 centers across Germany. Patients are randomized in a 1:1 ratio (7-21 days post-transplantation) to receive everolimus (trough levels 3-8 ng/mL) with reduced tacrolimus (trough levels <5 ng/mL), or standard tacrolimus (trough levels 6-10 ng/mL) after entering a run-in period (3-5 days post-transplantation). In the run-in period, patients are treated with induction therapy, mycophenolate mofetil, tacrolimus, and corticosteroids according to local practice. Randomization is stratified by HCV status and model of end-stage liver disease scores at transplantation. The primary objective of the study is to exhibit superior renal function (estimated glomerular filtration rate assessed by the Modification of Diet in Renal Disease (MDRD)-4 formula) with everolimus plus reduced tacrolimus compared to standard tacrolimus at Month 12. Other objectives are: to assess the incidence of treated biopsy-proven acute rejection, graft loss, or death; the incidences of components of the composite efficacy endpoint; renal function via estimated glomerular filtration rate using various formulae (MDRD-4, Nankivell, Cockcroft-Gault, chronic kidney disease epidemiology collaboration and Hoek formulae); the incidence of proteinuria; the incidence of adverse events and serious adverse events; the incidence and severity of cytomegalovirus and HCV infections and HCV-related fibrosis.

DISCUSSION

This study aims to demonstrate superior renal function, comparable efficacy, and safety in de novo liver transplant recipients receiving everolimus with reduced tacrolimus compared with standard tacrolimus. This study also evaluates the antiviral benefit by early initiation of everolimus.

TRIAL REGISTRATION

NCT01551212 .

Effect of delayed CNI-based immunosuppression with Advagraf® on liver function after MELD-based liver transplantation [IMUTECT]

BACKGROUND

MELD-based allocation for liver transplantation follows the "sickest-patient-first" strategy. The latter patients present with both, decreased immune competence and poor kidney function which is further impaired by immunosuppressants.

METHODS/DESIGN

In this prospective observational study, 50 patients with de novo low-dose standard Advagraf®-based immunosuppression consisting of Advagraf®, Mycophenolat-mofetil and Corticosteroids after liver transplantation will be evaluated. Advagraf® trough levels of 7-10 μg/l will be reached at the end of the first postoperative week. Immunostatus, infectious complications, graft and kidney function are compared between patients with a pretransplant calculated MELD-score of ≤20 and >20. Each group comprises of 25 consecutive patients. Prior to liver transplantation and on the postoperative days 1, 3 and 7, the patients' graft function (LiMAx test) will be evaluated. On the postoperative days 3, 5 and 7 the patients' immune status will be evaluated by the measurement of their monocytic HLA-DR status.Infectious complications (CMV-reactivation, wound infection, urinary tract infection, and pneumonia), graft- and kidney function will be analysed on day 0, within the first week, and 1, 3, 6, 9 and 12 months after liver transplantation.

DISCUSSION

This study was designed to assess the effect of a standard low-dose Calcineurin inhibitor-based immunosuppression regime with Advagraf® on the rate of infectious complications, graft and renal function after liver transplantation.

TRIAL REGISTRATION

The trial is registered at "Clinical Trials" (http://www.clinicaltrials.gov), NCT01781195.

Outcome stagnation of liver transplantation for primary sclerosing cholangitis in the Model for End-Stage Liver Disease era

PURPOSE

Survival after liver transplantation (LTX) has decreased in Germany since the implementation of Model for end-stage liver disease (MELD)-based liver allocation. Primary sclerosing cholangitis (PSC) is known for its otherwise excellent outcome after LTX. The influence of MELD-based liver allocation and subsequent allocation policy alterations on the outcome of LTX for PSC is analyzed.

METHODS

This is a retrospective observational study including 126 consecutive patients treated with LTX for PSC between January 1, 1999 and August 31, 2012. The PSC cohort was further compared to all other indications for LTX in the study period (n=1420) with a mean follow-up of 7.9 years (SD 3.2). Multivariate risk-adjusted analyses were performed. Alterations of allocation policy have been taken into account systematically.

RESULTS

Transplant recipients suffering from PSC are significantly younger (p<0.001), can be discharged earlier (p=0.018), and have lower 3-month mortality than patients with other indications (p=0.044). The observed time on the waiting list is significantly longer for patients with PSC (p<0.001), and there is a trend toward lower match MELD points in the PSC cohort (p=0.052). No improvement in means of short-term mortality could be shown in relation to alterations of allocation policy within the MELD era (p=0.375). Survival rates of the pre-MELD era did not differ significantly from those of the MELD era (p=0.097) in multivariate risk-adjusted analysis. Patients in the MELD era suffered pre-transplant significantly more frequently from dominant bile duct stenosis (p=0.071, p=0.059, p=0.048, respectively; chi2).

CONCLUSIONS

Progress is stagnating in LTX for PSC. Current liver allocation for PSC patients should be reconsidered.

Liver transplantation for malignancy: Current treatment strategies and future perspectives

In 1967, Starzl et al performed the first successful liver transplantation for a patient diagnosed with hepatoblastoma. In the following, liver transplantation was considered ideal for complete tumor resection and potential cure from primary hepatic malignancies. Several reports of liver transplantation for primary and metastatic liver cancer however showed disappointing results and the strategy was soon dismissed. In 1996, Mazzaferro et al introduced the Milan criteria, offering liver transplantation to patients diagnosed with limited hepatocellular carcinoma. Since then, liver transplantation for malignant disease is an ongoing subject of preclinical and clinical research. In this context, several aspects must be considered: (1) Given the shortage of deceased-donor organs, long-term overall and disease free survival should be comparable with results obtained in patients transplanted for non-malignant disease; (2) In this regard, living-donor liver transplantation may in selected patients help to solve the ethical dilemma of optimal individual patient treatment vs organ allocation justice; and (3) Ongoing research focusing on perioperative therapy and anti-proliferative immunosuppressive regimens may further reduce tumor recurrence in patients transplanted for malignant disease and thus improve overall survival. The present review gives an overview of current indications and future perspectives of liver transplantation for malignant disease.

[Patient selection and indications for liver transplantation]

Liver transplantation represents an established component of the therapeutic repertoire for irreversible chronic liver diseases. Liver transplantation is confronted by a shortage of donor allografts as well as by an increasing overall number of potentially useful indications, which leads to a rationing of this therapeutic option. Since December 2006 the priority for liver transplantation is determined by the model for end-stage liver disease (MELD) and not by the length of waiting time. The evaluation of indications which are prioritized according to laboratory values (serum creatine, serum bilirubin and coagulation) and the so-called standard exception categories which have to fulfil specific criteria place increased demands on the interdisciplinary transplantation team, on the evaluation for liver transplantation and the prediction of the success of transplantation required by the Transplantation Act. The establishment and implementation of robust, objective and transparent systems to assess not only preoperative priorities but also postoperative benefits represents a major challenge for transplantation medicine.

Prognostic limitations of the Eurotransplant-Donor Risk Index in liver transplantation

Background

Liver transplantation is the only life-saving therapeutic option for end-stage liver disease. Progressive donor organ shortage and declining donor organ quality justify the evaluation of the leverage of the Donor-Risk-Index, which was recently adjusted to the Eurotransplant community’s requirements (ET-DRI). We analysed the prognostic value of the ET-DRI for the prediction of outcome after liver transplantation in our center within the Eurotransplant community.

Results

291 consecutive adult liver transplants were analysed in a single centre study with ongoing data collection. Determination of the area under the receiver operating characteristic curve (AUROC) was performed to calculate the sensitivity, specificity, and overall correctness of the Eurotransplant-Donor-Risk-Index (ET-DRI) for the prediction of 3-month and 1-year mortality, as well as 3-month and 1-year graft survival. Cut-off values were determined with the best Youden-index. The ET-DRI is unable to predict 3-month mortality (AUROC: 0.477) and 3-month graft survival (AUROC: 0.524) with acceptable sensitivity, specificity and overall correctness (54% and 56.3%, respectively). Logistic regression confirmed this finding (p = 0.573 and p = 0.163, respectively). Determined cut-off values of the ET-DRI for these predictions had no significant influence on long-term patient and graft survival (p = 0.230 and p = 0.083, respectively; Kaplan-Meier analysis with Log-Rank test).

Conclusions

The ET-DRI should not be used for donor organ allocation policies without further evaluation, e.g. in combination with relevant recipient variables. Robust and objective prognostic scores for donor organ allocation purposes are desperately needed to balance equity and utility in donor organ allocation.

Respiratory risk score for the prediction of 3-month mortality and prolonged ventilation after liver transplantation

Survival of critically ill patients is significantly affected by prolonged ventilation. The goal of this study was the development of a respiratory risk score (RRS) for the prediction of 3-month mortality and prolonged ventilation after liver transplantation (LT). Two hundred fifty-four consecutive LT patients from a single center were retrospectively randomized into a training group for model design and a validation group. A receiver operating characteristic (ROC) curve analysis was used to test sensitivity and specificity. The accuracy of the predictions was assessed with the Brier score, and the model calibration was assessed with the Hosmer-Lemeshow test. Cutoff values were determined with the best Youden index. The RRS was calculated in the first 24 hours as follows: (laboratory Model for End-Stage Liver Disease score > 30 = 2.36 points) + (fresh frozen plasma > 13.5 U = 2.70 points) + (partial pressure of arterial oxygen/fraction of inspired oxygen ratio < 200 mm Hg = 2.23 points) + (packed red blood cells > 10.5 U = 3.50 points) + (preoperative mechanical ventilation = 3.87 points) +  (preoperative dialysis = 2.83 points) + (donor steatosis hepatis > 40% = 2.95 points). The RSS demonstrated high predictive accuracy, good model calibration, and c statistics > 0.7 in the training and validation groups. The RSS was able to predict 3-month mortality [cutoff = 6.64, area under the (ROC) curve (AUROC) = 0.794] and prolonged ventilation (cutoff = 3.69, AUROC = 0.798) with sensitivities of 69% and 81%, specificities of 83% and 73%, and overall model correctness of 76% and 77%, respectively. In conclusion, this study provides the first prognostic model for the prediction of 3-month mortality and prolonged ventilation after LT with high sensitivity and specificity and good model accuracy. The application of the RRS to an external cohort would be desirable for its further validation and introduction as a clinical tool for intensive care resource planning and prognostic decision making.

[Extended donor criteria defined by the German Medical Association : study on their usefulness as prognostic model for early outcome after liver transplantation]

Einleitung

Die Expansion des Spenderpools durch die Verwendung von Spenderorganen, die erweiterte Spenderkriterien erfüllen, verringert die Wartelistenmortalität mit einem erhöhten Risiko für das Patienten- und Transplantatüberleben nach Lebertransplantation. Die Eignung der Anzahl der erfüllten erweiterten Spenderkriterien nach der aktuellen Definition der Bundesärztekammer (BÄK-Score) für die Voraussage der frühen Ergebnisse nach Lebertransplantation ist unbekannt.

Patientenkollektiv

Untersucht wurden 257 erwachsene Empfänger, die zwischen dem 01.01.2007 und dem 31.12.2010 insgesamt 291 konsekutive Lebertransplantate erhielten.

Methoden

Primäre Studienendpunkte waren die 30-Tage-Mortalität, 3-Monats-Mortalität, das 3-Monats-Patientenüberleben, 3-Monats-Transplantatüberleben und die Notwendigkeit einer akuten Retransplantation innerhalb von 30 Tagen. Der BÄK-Score wurde als prognostisches Modell mit der ROC-Kurven-Analyse mit Bestimmung der Sensitivität, Spezifität und Gesamtmodellkorrektheit des Modells für die Voraussage der primären Studienendpunkte untersucht. Weiterhin wurden Kaplan-Meier-Überlebensanalysen, Log-Rank-Tests, Cox-Regressionsanalysen, logistische Regressionen und χ²-Tests durchgeführt.

Ergebnisse

Die Anzahl der erfüllten erweiterten Spenderkriterien hatte keinen signifikanten Einfluss auf die primären Studienendpunkte (p > 0,05) und das Patientenüberleben (p > 0,05). Die ROC-Kurven-Analyse zeigte für die Voraussage der primären Studienendpunkte Flächen ≤ 0,561 mit einer Gesamtkorrektheit des Modells < 58% bei einer Sensitivität < 52%.

Schlussfolgerung

Die Anzahl der erfüllten erweiterten Spenderkriterien nach der aktuellen Definition der Bundesärztekammer kann die frühe Prognose innerhalb der ersten 3 Monate nach Lebertransplantation als prognostisches Modell nicht voraussagen.

Irreversible liver failure: treatment by transplantation: part 3 of a series on liver cirrhosis

BACKGROUND

Liver transplantation is the only established, causally directed treatment for irreversible chronic or acute liver failure.

METHODS

This review is based on papers retrieved by a selective search in the PubMed database, the index of randomized controlled trials of the European Society of Organ Transplantation, and the Cochrane database, along with an analysis of data from the authors' own center.

RESULTS

1199 liver transplantations were performed in Germany in 2011. The most common indications were alcoholic cirrhosis (28%), cirrhosis of other causes (24%), and intrahepatic tumors (20%). Among recipients, the sex ratio was nearly 1:1 and the median age was just under 50. Across Europe, the 1-, 5-, and 10-year survival rates after liver transplantation were 82%, 71% and 61%. In our own center, the Charité in Berlin, the corresponding rates were 90.4%, 79.6% and 70.3%, based on an experience of 100 to 120 cases per year. The current rate of functioning transplants five years after liver transplantation is 52.6% in Germany and 66.2% internationally. Standard immunosuppression consists of a calcineurin inhibitor, tacrolimus or cyclosporine A, and steroids. Early complications include primary functional failure of the transplant, hemorrhage, thrombosis, acute rejection, and biliary complications. Over the long term, complications that can impair the outcome include chronic rejection, biliary strictures, cardiovascular and metabolic adverse effects, nephrotoxicity, neurotoxicity, and opportunistic infections and malignancies.

CONCLUSION

Liver transplantation is a successful and well-established form of treatment that is nonetheless endangered by a shortage of donor organs and other structural and organizational difficulties.

Screening colonoscopy in liver transplant candidates: risks and findings

The indication for mandatory screening colonoscopies in liver transplant candidates is controversial. Since the introduction of MELD-based allocation, patients with advanced liver disease and often severe comorbidities are prioritized for liver transplantation (LT). This study evaluated safety and outcome of colonoscopy in this high-risk patient group. During a two-yr period, we performed 243 colonoscopies in potential LT candidates. Endoscopic findings were registered in a standardized form, and correlations with biochemical or clinical parameters were analyzed using Mann-Whitney U-test and chi-square test. Only 57 patients (23.5%) had an endoscopically normal colon. Main findings were polyps (45.7%), hypertensive colopathy (24.3%), diverticulosis (21%), rectal varices (19.8%), and hemorrhoids (13.6%). In 21% of all patients, the removed polyps were diagnosed as adenomas. The prevalence of neoplastic polyps increased significantly with age: 13.6% (patients <50 yr) vs. 25% (patients ≥ 50 yr) (p = 0.03). Advanced neoplasia was found only in patients older than 40 yr. No major complications were observed; post-interventional hemorrhage was observed in 1.7% and controlled by clipping or injection therapy. In conclusion, lower gastrointestinal endoscopy is safe and effective in LT candidates. Due to the age dependency of neoplastic polyps, a screening colonoscopy should be performed in LT candidates older than 40 yr or with symptoms or additional risk factors.

Use of N-acetylcysteine during liver procurement: a prospective randomized controlled study

Antioxidant agents have the potential to reduce ischemia/reperfusion damage to organs for liver transplantation (LT). In this prospective, randomized study, we tested the impact of an infusion of N-acetylcysteine (NAC) during liver procurement on post-LT outcomes. Between December 2006 and July 2009, 140 grafts were transplanted into adult candidates with chronic liver disease who were listed for first LT, and according to a sequential, closed-envelope, single-blinded procedure, these patients were randomly assigned in a 1/1 ratio to an NAC protocol (69 patients) or to the standard protocol without NAC [71 patients (the control group)]. The NAC protocol included a systemic NAC infusion (30 mg/kg) 1 hour before the beginning of liver procurement and a locoregional NAC infusion (300 mg through the portal vein) just before cross-clamping. The primary endpoint was graft survival. The graft survival rates at 3 and 12 months were 93% and 90%, respectively, in the NAC group and 82% and 70%, respectively, in the control group (P = 0.02). An adjusted Cox analysis showed a significant NAC effect on graft survival at both 3 months [hazard ratio = 1.65, 95% confidence interval (CI) = 1.01-2.93, P = 0.04] and 12 months (hazard ratio = 1.73, 95% CI = 1.14-2.76, P ≤ 0.01). The incidence of postoperative complications was lower in the NAC group (23%) versus the control group (51%, P < 0.01). In the subgroup of 61 patients (44%) receiving suboptimal grafts (donor risk index > 1.8), the incidence of primary dysfunction of the liver was lower (P = 0.09) for the NAC group (15%) versus the control group (32%). In conclusion, the NAC harvesting protocol significantly improves graft survival. The effect of NAC on early graft function and survival seems higher when suboptimal grafts are used.