Prediction of graft dysfunction based on extended criteria donors in the model for end-stage liver disease score era

A preliminary European Liver and Intestine Transplant Association-European Liver Transplant Registry study on informed recipient consent and extended criteria liver donation

The European Liver and Intestine Transplant Association (ELITA) and the European Liver Transplant Registry (ELTR) coordinated the distribution to European liver transplantation centers of an electronic questionnaire, developed by the first author, concerning the definition of extended criteria liver donation (ECD) and the implication for informed consent of transplant recipients. Completed questionnaires were received from 35 centers. All centers accepted ECD liver donors. The criteria for defining a liver donor as ECD were as follows: steatosis in 33 centers (94%); age up to 80 years in 15 centers (43%); serum sodium >165 mmol/L in 25 centers (71%); intensive care unit (ICU) stay with ventilation longer than 7 days in 17 centers (48%); aspartate aminotransferase (AST) >90 U/L, in 6 centers (17%); body mass index (BMI) >30 in 19 centers (54%); alanine aminotransferase (ALT) >105 U/L in 8 centers (23%); serum bilirubin >3 mg/dL in 15 centers (43%); and all criteria together in 2 centers (6%). Thirty-one centers informed the transplantation candidate of the ECD status of the donor, 20 (65%) when the patient registered for transplantation, 1 (3%) when an ECD liver became available, and 10 centers (32%) on both occasions. Thirteen centers required the liver transplantation candidate to sign a special consent form. Twenty centers informed the potential recipient of the donor's serology. Only 6 centers informed the potential recipient of any high-risk behavior of the donor.

Live liver donors' risk thresholds: risking a life to save a life

BACKGROUND

There is still some controversy regarding the ethical issues involved in live donor liver transplantation (LDLT) and there is uncertainty on the range of perioperative morbidity and mortality risks that donors will consider acceptable.

METHODS

This study analysed donors' inclinations towards LDLT using decision analysis techniques based on the probability trade-off (PTO) method. Adult individuals with an emotional or biological relationship with a patient affected by end-stage liver disease were enrolled. Of 122 potential candidates, 100 were included in this study.

RESULTS

The vast majority of participants (93%) supported LDLT. The most important factor influencing participants' decisions was their wish to improve the recipient's chance of living a longer life. Participants chose to become donors if the recipient was required to wait longer than a mean ± standard deviation (SD) of 6 ± 5 months for a cadaveric graft, if the mean ± SD probability of survival was at least 46 ± 30% at 1 month and at least 36 ± 29% at 1 year, and if the recipient's life could be prolonged for a mean ± SD of at least 11 ± 22 months.

CONCLUSIONS

Potential donors were risk takers and were willing to donate when given the opportunity. They accepted significant risks, especially if they had a close emotional relationship with the recipient.

The evolving use of higher risk grafts is associated with an increased incidence of acute kidney injury after liver transplantation

BACKGROUND & AIMS

The growing discrepancy between supply and demand for liver transplantation has necessitated a greater use of higher risk grafts. Donation after Circulatory Death (DCD) liver transplant recipients have an increased frequency of acute kidney injury (AKI). We hypothesised that other higher risk grafts might also impact negatively on renal function. Our aim was to examine the effect of the evolving use of higher risk grafts on the incidence of post liver transplant AKI.

METHODS

Single-centre study of 1152 patients undergoing first-single-organ liver transplantation for chronic liver disease 01/2000-12/2011. To assess the impact of the evolution of graft quality over time; donor/graft/recipient variables were compared over three 4-year periods.

RESULTS

Pretransplant recipient renal function improved during follow-up (p<0.001), and the median postoperative day-1 (p<0.001), -2 (p<0.001), and -3 (p<0.001) tacrolimus trough levels fell. The proportion of patients receiving a higher risk graft was 31.8% in 2000-2003, 40.9% in 2004-2007, and 59.1% in 2008-2011 (p<0.001). There was a progressive increase in AKI (2000-2003, OR 1.00; 2004-2007, OR 1.43; 2008-2011, OR 2.40, p<0.001). After adjusting for recipient variables increasing recipient warm ischaemic time (p=0.019), DCD transplantation (p<0.001), donor age ≥60 years (p=0.020), and donor body mass index ≥30 kg/m(2) (p<0.001) were independent predictors of AKI.

CONCLUSIONS

The increasing use of higher risk liver grafts is associated with an increased incidence of AKI. These findings support the need for therapies that minimise the hepatic ischaemia-reperfusion injury.

Primary graft dysfunction after liver transplantation

BACKGROUND

Primary graft dysfunction (PGD) causes complications in liver transplantation, which result in poor prognosis. Recipients who develop PGD usually experience a longer intensive care unit and hospital stay and have higher mortality and graft loss rates compared with those without graft dysfunction. However, because of the lack of universally accepted definition, early diagnosis of graft dysfunction is difficult. Additionally, numerous factors affect the allograft function after transplantation, making the prediction of PGD more difficult. The present review was to analyze the literature available on PGD and to propose a definition.

DATA SOURCE

A search of PubMed (up to the end of 2012) for English-language articles relevant to PGD was performed to clarify the characteristics, risk factors, and possible treatments or interventions for PGD.

RESULTS

There is no pathological diagnostic standard; many documented definitions of PGD are different. Many factors, such as donor status, procurement and transplant process and recipient illness may affect the function of graft, and ischemia-reperfusion injury is considered the direct cause. Potential managements which are helpful to improve graft function were investigated. Some of them are promising.

CONCLUSIONS

Our analyses suggested that the definition of PGD should include one or more of the following variables: (1) bilirubin ≥ 10 mg/dL on postoperative day 7; (2) international normalized ratio ≥ 1.6 on postoperative day 7; and (3) alanine aminotransferase or aspartate aminotransferase >2000 IU/L within 7 postoperative days. Reducing risk factors may decrease the incidence of PGD. A majority of the recipients could recover from PGD; however, when the graft progresses into primary non-function, the patients need to be treated with re-transplantation.

A proposal to grade the severity of early allograft dysfunction after liver transplantation

Objective:

To propose a grading system for early hepatic graft dysfunction.

Methods:

A retrospective study from a single transplant center. Recipients of liver transplants from deceased donors, transplanted under the MELD system were included. Early graft dysfunction was defined by Olthoff criteria. Multiple cut-off points of post-transplant laboratory tests were used to create a grading system for early graft dysfunction. The primary outcome was 6-months grafts survival.

Results:

The peak of aminotransferases during the first postoperative week correlated with graft loss. The recipients were divided into mild (aminotransferase peak >2,000IU/mL, but <3,000IU/mL); moderate (aminotransferase peak >3,000IU/mL); and severe (aminotransferase peak >3,000IU/mL + International Normalized Ratio ≥1.6 and/or bilirubin ≥ 10mg/dL in the 7^th postoperative day) early allograft dysfunction. Moderate and severe early dysfunctions were independent risk factors for graft loss. Patients with mild early dysfunction presented with graft and patient survival comparable to those without graft dysfunction. However, those with moderate early graft dysfunction showed worse graft survival than those who had no graft dysfunction. Patients with severe early dysfunction had graft and patient survival rates worse than those of any other groups.

Conclusion:

Early graft dysfunction can be graded by a simple and reliable criteria based on the peak of aminotransferases during the first postoperative week. The severity of the early graft dysfunction is an independent risk factor for allograft loss. Patients with moderate early dysfunction showed worsening of graft survival. Recipients with severe dysfunction had a significantly worse prognosis for graft and patient survival.

The difficulty in defining extended donor criteria for liver grafts: the Eurotransplant experience

Donor criteria for liver grafts have been expanded because of organ shortage. Currently, no exact definitions for extended donor grafts have been established. The aim of this study was to analyze the impact of donor-specific risk factors, independent of recipient characteristics. In collaboration with Eurotransplant and European Liver Transplant Register, solely donor-specific parameters were correlated with 1-year survival following liver transplantation. Analyses of 4701 donors between 2000 and 2005 resulted in the development of a nomogram to estimate graft survival for available grafts. Predictions by nomogram were compared to those by Donor Risk Index (DRI). In the multivariate analysis, cold ischemic time (CIT), highest sodium, cause of donor death, γ-glutamyl transferase (γ-GT), and donor sex (female) were statistically significant factors for 3 months; CIT, γ-GT, and cause of donor death for 12-month survival. The median DRI of this study population was 1.45 (Q1: 1.17; Q3: 1.67). The agreement between the nomogram and DRI was weak (kappa = 0.23). Several donor-specific risk factors were identified for early survival after liver transplantation. The provided nomogram will support quick organ quality assessment. Nevertheless, this study showed the difficulties of determining an exact definition of extended criteria donors.

Why offered pancreases are refused in the allocation process-a descriptive study using routine data from eurotransplant

BACKGROUND

The majority of pancreases, offered in allocation, are discarded. This pancreas underutilization is not well understood yet.

METHODS

We analyzed the detailed allocation protocols of all Eurotransplant-registered German whole-pancreas donors (2005-2009; n=1758). Outcome measures included donor characteristics, number of refusals per organ, and proportion of different refusal reasons in the whole sample and subgroups.

RESULTS

Thirty-seven percent of offered pancreases were transplanted; among these, 62% of pancreases were of potentially high quality (favorable donor age and pre-procurement pancreas allocation suitability score, no malignancy, n=290). A pancreas was placed after four offers (median) or withdrawn after eight offers (median). Seventy-five percent of refusal reasons were donor related (e.g., "lab results", "age", "macroscopy", and "long intensive care unit [ICU] stay"). Among pancreases refused for "diabetes" or "malignancy" at least once, the proportion of transplanted organs was less than 10%; pancreases refused due to "trauma", "age", or "resuscitation" were later transplanted in 48%, 32%, and 28%, respectively. The impact of donor age and ICU stay on organ refusal varied substantially: organs were refused due to length of ICU stay even if donors stayed 7 days or less; some organs were transplanted without ever being refused due to ICU stay in donors who stayed 8 days or more in ICU. There were no clinically significant disparities between donors of used and unused pancreases, except age (median, 31 vs. 42 years).

DISCUSSION

The loss of several pancreases seems avoidable. Many refusal reasons are not plausible, because there is no evidence supporting the refusal and because many of these organs were transplanted by other centers. This increases inefficiency in the allocation system.

Donor-recipient matching: myths and realities

Liver transplant outcomes keep improving, with refinements of surgical technique, immunosuppression and post-transplant care. However, these excellent results and the limited number of organs available have led to an increasing number of potential recipients with end-stage liver disease worldwide. Deaths on waiting lists have led liver transplant teams maximize every organ offered and used in terms of pre and post-transplant benefit. Donor-recipient (D-R) matching could be defined as the technique to check D-R pairs adequately associated by the presence of the constituents of some patterns from donor and patient variables. D-R matching has been strongly analysed and policies in donor allocation have tried to maximize organ utilization whilst still protecting individual interests. However, D-R matching has been written through trial and error and the development of each new score has been followed by strong discrepancies and controversies. Current allocation systems are based on isolated or combined donor or recipient characteristics. This review intends to analyze current knowledge about D-R matching methods, focusing on three main categories: patient-based policies, donor-based policies and combined donor-recipient systems. All of them lay on three mainstays that support three different concepts of D-R matching: prioritarianism (favouring the worst-off), utilitarianism (maximising total benefit) and social benefit (cost-effectiveness). All of them, with their pros and cons, offer an exciting controversial topic to be discussed. All of them together define D-R matching today, turning into myth what we considered a reality in the past.

Early allograft dysfunction and liver transplant outcomes: a single center retrospective study

BACKGROUND

Early allograft dysfunction (EAD) had been related to poor transplant outcomes during the early years of liver transplantation. We sought to determine the incidence of EAD at our unit and to evaluate its impact on posttransplant outcomes.

METHODS

This single-center retrospective study included primary deceased donor liver grafts transplanted under the model for end-stage liver disease system. EAD was defined as a peak values of aminotransferase >2000 IU/mL during the first week or an international normalized ratio of ≥1.6 and/or bilirubin ≥10 mg/dL at day 7. The main endpoints were patient and graft survivals.

RESULTS

Patients with versus without EAD showed similar recipient characteristics. Donors who experienced EAD who comprises 56% of recipients were heavier with larger body mass indices. EAD was an independent risk factor for allograft loss. Most retransplants were performed early due to nonfunction. The primary nonfunction rate among subjects with versus without EAD were 7% and 12% respectively (P < .05). Patient survival among those with EAD was 87.4%, while without EAD it was 90% (P = NS) with graft survivals of 81.4% and 88.7% respectively (P < .05).

CONCLUSION

Patients with EAD show a significantly higher risk for allograft loss, but with a comparable survival after transplantation. Despite their worse outcomes, it seems that not all of these recipients behave equally.

Model for End-stage Liver Disease

Model for end-stage liver disease (MELD) score, initially developed to predict survival following transjugular intrahepatic portosystemic shunt was subsequently found to be accurate predictor of mortality amongst patents with end-stage liver disease. Since 2002, MELD score using 3 objective variables (serum bilirubin, serum creatinine, and institutional normalized ratio) has been used worldwide for listing and transplanting patients with end-stage liver disease allowing transplanting sicker patients first irrespective of the wait time on the list. MELD score has also been shown to be accurate predictor of survival amongst patients with alcoholic hepatitis, following variceal hemorrhage, infections in cirrhosis, after surgery in patients with cirrhosis including liver resection, trauma, and hepatorenal syndrome (HRS). Although, MELD score is closest to the ideal score, there are some limitations including its inaccuracy in predicting survival in 15-20% cases. Over the last decade, many efforts have been made to further improve and refine MELD score. Until, a better score is developed, liver allocation would continue based on the currently used MELD score.

Protective effects of branched-chain amino acids on hepatic ischemia-reperfusion-induced liver injury in rats: a direct attenuation of Kupffer cell activation

We determined whether there is a protective effect of branched-chain amino acid (BCAA) on hepatic ischemia-reperfusion (I/R)-induced acute liver injury. Wister rats were divided into the following four groups: simple laparotomy with vehicle; simple laparotomy with BCAA (1 g/kg body wt orally); I/R (30 min clamp) with vehicle; and I/R with BCAA. Serum liver function tests and the gene expression of adhesion molecules (intercellular adhesion molecule and vascular cell adhesion molecule) and vasoconstrictor-related genes (endothelin-1) in the liver were examined. In the in vivo study, portal venous pressure, leukocyte adhesion, and hepatic microcirculation were evaluated. Furthermore, Kupffer cells were isolated and cultured with various concentrations of BCAA in the presence or absence of lipopolysaccharide (LPS). Increased levels of liver function tests following I/R were significantly attenuated by BCAA treatment. The increased expression of adhesion molecules and endothelin-1 was also significantly attenuated by BCAA treatment. Moreover, increased portal venous pressure, enhanced leukocyte adhesion, and deteriorated hepatic microcirculation following I/R were all improved by BCAA treatment. In the experiment using isolated Kupffer cells, the expression of interleukin-6, interleukin-1β, and endothelin-1 in response to LPS stimulation was attenuated by BCAA in a dose-dependent fashion. These results indicate that perioperative oral administration of BCAA has excellent therapeutic potential to reduce I/R-induced liver injury. These beneficial effects may result from the direct attenuation of Kupffer cell activation under stressful conditions.

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.

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

INTRODUCTION

Expansion of the donor pool by the use of grafts with extended donor criteria reduces waiting list mortality with an increased risk for graft and patient survival after liver transplantation. The ability of the number of fulfilled extended donor criteria as currently defined by the German Medical Association (BÄK-Score) to predict early outcome is unclear.

PATIENTS

A total of 291 consecutive adult liver transplantations (01.01.2007-31.12.2010) in 257 adult recipients were analyzed.

METHODS

Primary study endpoints were 30 day mortality, 3 month mortality, 3 month patient and graft survival and the necessity of acute retransplantation within 30 days. For primary study endpoints a ROC curve analysis was performed to calculate sensitivity, specificity and overall model correctness of the BÄK score as a predictive model. Further methods included Kaplan-Meier estimates, log-rank tests, Cox regression analysis, logistic regression analysis and χ(2)-tests.

RESULTS

The number of extended donor criteria fulfilled had no statistically significant influence on the primary study endpoints (p > 0.05) or on patient survival (p > 0.05). ROC curve analysis revealed areas under the curve ≤ 0.561 for the prediction of primary study endpoints (overall model correctness < 58%, sensitivity < 52%).

CONCLUSIONS

The number of fulfilled extended donor criteria as currently defined by the German Medical Association is unable to predict early outcome after liver transplantation.

Donation after cardio-circulatory death liver transplantation

The renewed interest in donation after cardio-circulatory death (DCD) started in the 1990s following the limited success of the transplant community to expand the donation after brain-death (DBD) organ supply and following the request of potential DCD families. Since then, DCD organ procurement and transplantation activities have rapidly expanded, particularly for non-vital organs, like kidneys. In liver transplantation (LT), DCD donors are a valuable organ source that helps to decrease the mortality rate on the waiting lists and to increase the availability of organs for transplantation despite a higher risk of early graft dysfunction, more frequent vascular and ischemia-type biliary lesions, higher rates of re-listing and re-transplantation and lower graft survival, which are obviously due to the inevitable warm ischemia occurring during the declaration of death and organ retrieval process. Experimental strategies intervening in both donors and recipients at different phases of the transplantation process have focused on the attenuation of ischemia-reperfusion injury and already gained encouraging results, and some of them have found their way from pre-clinical success into clinical reality. The future of DCD-LT is promising. Concerted efforts should concentrate on the identification of suitable donors (probably Maastricht category III DCD donors), better donor and recipient matching (high risk donors to low risk recipients), use of advanced organ preservation techniques (oxygenated hypothermic machine perfusion, normothermic machine perfusion, venous systemic oxygen persufflation), and pharmacological modulation (probably a multi-factorial biologic modulation strategy) so that DCD liver allografts could be safely utilized and attain equivalent results as DBD-LT.

Experience using extended criteria donors in first 100 cases of deceased donor liver transplantation in Japan

Because of the serious organ shortage in Japan, the use of extended criteria (EC) donors is inevitable to increase the number of deceased donors. However, the influence of this practice on recipient outcomes has not been clarified yet. We analyzed donor and recipient factors to determine whether those factors, especially from EC donors impacted early recipient outcomes. From February 1999 to January 2011, 100 deceased liver transplantations were performed in Japan, including 85 consecutive adult cases (age≥18 years) who were studied to evaluate whether 6 recipient and 16 donor factors affected 3-month (90-day) recipient survival. Upon univariate analysis, Model for End-stage Liver Disease (MELD) score≥25 (P=.018), donor age≥55 years (P=.040), and cold ischemia time (CIT)≥10 hours (P=.00013) significantly reduced 3-month survival. Multivariate analysis confirmed the independent contributions of, three adverse factors including MELD score≥25 (P=.0133, odds ratio [OR]=12.3, 95% confidence interval [CI]=1.7-90.3), donor age≥55 years (P=.013, OR=14.0, 95% CI=1.6-119.5), and CIT≥10 hours (P=.0024, OR=67.6, 95% CI=4.5-1024.9). Three-month recipient survivals with 0, 1, 2, and 3 positive factors were 100% (n=34), 94.4% (n=36), 53.8% (n=13), and 0% (n=2), respectively (P<.0001). In conclusion, to improve recipient short-term survivals, minimizing CIT is the first priority. In the long-term, we must promote deceased donation to reduce recipient MELD scores by shortening the waiting time, and revise the allocation system to minimize CIT by giving priority to the local area.

Patients' willingness to accept expanded criteria donor liver transplantation

Utilization of livers from expanded criteria donors (ECD) is one strategy to overcome the severe organ shortage. The decision to utilize an ECD liver is complex and fraught with uncertainty for both providers and patients. We assessed patients' willingness to accept ECD liver transplantation (LTx) and acceptable 1-year mortality risk. One hundred eight patients listed for LTx were asked to rate their willingness to accept ECD LTx and the associated 1-year mortality risk they were willing to accept. Also, patients completed the SF-36v2 and sociodemographic and health information was gathered from their medical records. Patients reported significantly higher willingness to accept standard criteria donor (SCD) versus ECD LTx (t = 13.8, p < 0.001), with more than one-third of patients reporting low willingness to accept ECD LTx. Relative to our center's 10% SCD LTx 1-year mortality rate, most patients (71%) were willing to accept moderately or substantially higher 1-year mortality risk for ECD LTx. In multivariable analyses, higher lab MELD score and white race were significant independent predictors of both ECD willingness and ECD increased mortality risk acceptability. Findings highlight the importance of assessing patients' willingness to pursue ECD LTx and the relative mortality risks they are willing to accept.