Who should get a liver graft?

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

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

Machine learning in liver transplantation: a tool for some unsolved questions?

Machine learning has recently been proposed as a useful tool in many fields of Medicine, with the aim of increasing diagnostic and prognostic accuracy. Models based on machine learning have been introduced in the setting of solid organ transplantation too, where prognosis depends on a complex, multidimensional and nonlinear relationship between variables pertaining to the donor, the recipient and the surgical procedure. In the setting of liver transplantation, machine learning models have been developed to predict pretransplant survival in patients with cirrhosis, to assess the best donor-to-recipient match during allocation processes, and to foresee postoperative complications and outcomes. This is a narrative review on the role of machine learning in the field of liver transplantation, highlighting strengths and pitfalls, and future perspectives.

Longterm Outcomes of Patients Undergoing Liver Transplantation for Acute-on-Chronic Liver Failure

Recent data have demonstrated >80% 1-year survival probability after liver transplantation (LT) for patients with severe acute-on-chronic liver failure (ACLF). However, longterm outcomes and complications are still unknown for this population. Our aim was to compare longterm patient and graft survival among patients transplanted across all grades of ACLF. We analyzed the United Network for Organ Sharing database for the years 2004-2017. Patients with ACLF were identified using the European Association for the Study of the Liver-Chronic Liver Failure criteria. Kaplan-Meier and Cox regression methods were used to determine patient and graft survival and associated predictors of mortality in adjusted models. A total of 56,801 patients underwent transplantation of which 31,024 (54.6%) had no ACLF, 8757 (15.4%) had ACLF grade 1, 9039 (15.9%) had ACLF grade 2, and 7891 (14.1%) had ACLF grade 3. The 5-year patient survival after LT was lower in the ACLF grade 3 patients compared with the other groups (67.7%; P < 0.001), although after year 1, the percentage decrease in survival was similar among all groups. Infection was the primary cause of death among all patient groups in the first year. Infection was the primary cause of death among all patient groups in the first year. After the first year, infection was the main cause of death in patients transplanted with ACLF grade 1 (32.1%), ACLF grade 2 (33.9%), and ACLF grade 3 (37.6%), whereas malignancy was the predominant cause of death in those transplanted with no ACLF (28.5%). In conclusion, patients transplanted with ACLF grade 3 had lower 5-year survival as compared with patients with ACLF grades 0-2, but mortality rates were not significantly different after the first year following LT. Graft survival was excellent across all ACLF groups.

Benefit in liver transplantation: a survey among medical staff, patients, medical students and non-medical university staff and students

Background

The allocation of any scarce health care resource, especially a lifesaving resource, can create profound ethical and legal challenges. Liver transplant allocation currently is based upon urgency, a sickest-first approach, and does not utilize capacity to benefit. While urgency can be described reasonably well with the MELD system, benefit encompasses multiple dimensions of patients’ well-being. Currently, the balance between both principles is ill-defined.

Methods

This survey with 502 participants examines how urgency and benefit are weighted by different stakeholders (medical staff, patients on the liver transplant list or already transplanted, medical students and non-medical university staff and students).

Results

Liver transplant patients favored the sickest-first allocation, although all other groups tended to favor benefit. Criteria of a successful transplantation were a minimum survival of at least 1 year and recovery of functional status to being ambulatory and capable of all self-care (ECOG 2). An individual delisting decision was accepted when the 1-year survival probability would fall below 50%. Benefit was found to be a critical variable that may also trigger the willingness to donate organs.

Conclusions

The strong interest of stakeholder for successful liver transplants is inadequately translated into current allocation rules.

Impact of body mass index on outcomes of 48281 patients undergoing first time cadaveric liver transplantation

AIM: To investigate possible disparities in perioperative morbidity and mortality among different body mass index (BMI) groups and to simulate the impact that these differences might have had on the cohort of patients undergoing cadaveric liver transplantation (LT).

METHODS: All adult recipients undergoing first time LT for benign conditions and receiving a whole graft from brain-dead donors were selected from the united network of organ sharing registry. From January 1994 to June 2013, 48281 patients satisfied the inclusion criteria and were stratified by their BMI. The hypothesis that abnormal BMIs were independent predictors of inferior outcomes was tested with univariate and multivariate regression analyses.

RESULTS: In comparison to normal weight recipients, underweight and morbidly obese recipients had increased 90-d mortality (adjusted OR = 1.737; 95%CI: 1.185-2.548, P = 0.005) (adjusted OR = 1.956; 95%CI: 1.473-2.597, P = 0.000) respectively and inferior patients’ survivals (adjusted HR = 1.265; 95%CI: 1.096-1.461, P = 0.000) (adjusted HR = 1.157; 95%CI: 1.031-1.299, P = 0.013) respectively. Overall, patients’ 5-year survival were 73.9% for normal-weight, 71.1% for underweight, 74.0% for overweight, 74.4% for class I obese, 75.0% for class II obese and 71.5% for class III obese recipients. Analysis of hypothetical exclusion of underweight and morbidly obese patients from the pool of potential LT candidates would have improved the overall survival of the entire cohort by 2.7% (95%CI: 2.5%-3.6%).

CONCLUSION: Selected morbidly obese patients undergoing LT for benign conditions had 5-year survival rates clinically comparable to normal weight recipients. Impact analysis showed that exclusion of high-risk recipients (underweight and morbid obese patients) would not significantly improve the overall survival of the entire cohort of patients requiring LT.

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.

Results of liver transplantation from old donors

INTRODUCTION

Faced with a shortage of organs for liver transplantation, the use of grafts from older donors is justified. However, there remains little consensus on how this use impacts the graft and patient outcomes after transplantation from these older donors. The aim of the present analysis was to assess the graft and patient outcomes after liver transplantation from deceased donors >60 years of age.

METHODS

From January 2007 to January 2011, 505 subjects were identified as liver graft donors after brain death, of which 7.35% were ≥60. To determine the effect of donor age on graft and patient outcomes, we analyzed donor age, recipient age, the Model for End-State Liver Disease (MELD) score of recipients at the time of transplantation, early posttransplant complications, and mortality.

RESULTS

The posttransplant follow-up was 29 ± 25.5 months, and 3-year patient mortality from donors, grouped according to age, was 7.92% with donors <30; 15.78% with donors 30-50, 10.68% with donors 50-60, and 12.50% with donors >60. After analysis of patient and graft survival based on donor graft age, 3-year patient survival according donor age was 89.29% with donors <30, 83.85% with donors 30-50, 89.89% with donors 50-60, and 87.50% with donors >60. Analysis showed overall patient and graft survival rates from older donors were not worse than those from younger donors (P > .1). Among the cases, 3-year patient survival according to MELD score was 91.19% with a MELD of I, 85.37% with a MELD of II, and 67.67% with a MELD of III; differences in graft and patient survival when comparing low MELD I and high MELD III were significantly different (P < .01).

CONCLUSIONS

A more advanced age of a donor should not be a contraindication for liver transplantation. The present analysis shows that liver grafts from donors >60 can be used safely in older recipients who presented with relatively low MELD scores. Analyses also indicate that high MELD obtained before transplantation may be an important prognostic factor for graft and patient survival.

High-risk liver transplant candidates: An ethical proposal on where to draw the line

In making liver transplantation (LT) listing decisions, transplant programs accept that very large differences in expected 5-year posttransplant survival should matter and that small differences in expected survival should not matter. To date, the transplant community has not explicitly addressed the difficult question of how to make decisions when the differences are less dramatic. Existing well-accepted transplant policies neither articulate a criterion for where to draw the line nor provide an ethical justification for distinguishing those who should not be eligible for transplantation from those who should be. Herein we analyze a case from our LT program that raises the issue of how much of a difference should separate the eligible from the ineligible. We explain how our ethical analysis is consistent with the Scientific Registry of Transplant Recipients cumulative sum metric for transplant center performance, the United Network for Organ Sharing standard of capping Model for End-Stage Liver Disease scores at 40 for listing purposes, and the longstanding tradition of allocating scarce medical resources in accordance with the principle of triage. We also discuss how subjectivity can influence judgments about likely outcomes. We conclude by calling for research to gather data that could make survival predictions objective and by proposing a policy that would make the treatment of all patients fair.

Management of “very early” hepatocellular carcinoma on cirrhotic patients

Due to the advances in screening of cirrhotic patients, hepatocellular carcinoma (HCC) is being diagnosed in earlier stages. For this reason the number of patients diagnosed of very early HCC (single tumors ≤ 2 cm) is continuously increasing. Once a patient has been diagnosed with this condition, treatment strategies include liver resection, local therapies or liver transplantation. The decision on which therapy should the patient undergo depends on the general patients performance status and liver disease. Anyway, even in patients with similar conditions, the best treatment offer is debatable. In this review we analyze the state of the art on the management of very early HCC on cirrhotic patients to address the best treatment strategy for this patient population.

Ethical considerations surrounding survival benefit-based liver allocation

The disparity between the demand for and supply of donor livers has continued to grow over the last 2 decades, and this has placed greater weight on the need for efficient and effective liver allocation. Although the use of extended criteria donors has shown great potential, it remains unregulated. A survival benefit-based model was recently proposed to answer calls to increase efficiency and reduce futile transplants. However, it was previously determined that the current allocation system was not in need of modification and that instead geographic disparities should be addressed. In contrast, we believe that there is a significant need to replace the current allocation system and complement efforts to improve donor liver distribution. We illustrate this need first by identifying major ethical concerns shaping liver allocation and then by using these concerns to identify strengths and shortcomings of the Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease system and a survival benefit-based model. The latter model is a promising means of improving liver allocation: it incorporates a greater number of ethical principles, uses a sophisticated statistical model to increase efficiency and reduce waste, minimizes bias, and parallels developments in the allocation of other organs. However, it remains limited in its posttransplant predictive accuracy and may raise potential issues regarding informed consent. In addition, the proposed model fails to include quality-of-life concerns and prioritize younger patients. We feel that it is time to take the next steps toward better liver allocation not only through reductions in geographic disparities but also through the adoption of a model better equipped to balance the many ethical concerns shaping organ allocation. Thus, we support the development of a similar model with suggested amendments.

A validated model for predicting outcome after liver transplantation: implications on transplanting the extremely sick

Given the organ shortage, there is a need to optimize outcome after liver transplantation (LT). We defined posttransplant hospital length of stay > 60 days (LOS > 60) as a surrogate of suboptimal outcome. In the first phase of the study, a 'Study cohort' (SC) of 643 patients was used to identify risk factors and construct a mathematical model to identify recipients with anticipated inferior results. In the second phase, a cohort of 417 patients was used for validation of the model ['Validation Cohort' (VC)]. In the SC, 65 patients (10.1%) had LOS > 60 days. One- and 3-year patient/graft survival rates were 81.9%/76.1% and 73.4%/67.4%, respectively. Patient and graft survival rates of those with LOS > 60 days were inferior (P < 0.0001), while transplant cost was greater [3.42 relative units (RU) vs. 1 RU, P < 0.0001]. In a multivariable analysis, pretransplant dialysis (P < 0.001), mechanical ventilation (P < 0.015), MELD (P < 0.003), and age (P < 0.009) were predictors of LOS > 60 days [ROC curve - 0.75 (95% CI 0.70, 0.81)]. In the VC, 53 patients (12.7%) were expected to have adverse outcome by the model. These patients had longer LOS (P < 0.0001), higher cost (<0.0001), and inferior patient and graft survival (P < 0.007).

Implications of changing the minimal survival benefit in liver transplantation

The limited availability of livers donated by deceased donors for transplantation means that not everyone who might benefit from the procedure can receive a graft, so any selection and allocation system must have clearly defined goals. The United Kingdom, in common with many other countries, has adopted a minimum benefit criterion of a greater than 50% probability of survival 5 years after transplantation. We investigated the impact of changing this minimum benefit criterion on a case mix of listed patients. The analysis was based on 5330 adult elective patients who underwent transplantation with livers from donation after brain death donors between January 1994 and December 2007. We examined the impact of balancing the number of registrations on the list with the number of available donor livers while allowing a 10% mortality rate and found that this would require a survival threshold of at least 74% at 5 years. According to historical data, the application of this more stringent criterion would significantly reduce the eligibility of older and nonwhite patients and patients with hepatocellular carcinoma or hepatitis C virus infections. Thus, if such undesirable restrictions on access to liver transplantation are to be avoided, we must consider alternative strategies such as the acceptance of higher transplant list mortality.

Development of organ-specific donor risk indices

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

Monday blues of deceased-donor liver transplantation

BACKGROUND

There is a constant and global shortage of deceased-donor organs for transplantation. Ways to identify areas for securing potential deceased-donor organs may improve the supply and hence benefit more patients in need of transplantation.

METHODS

We looked into the disparity of the number of deceased-donor liver transplantation (DDLT) performed at our hospital on different days of the weeks from January 2000 to the end of December 2009 (237 DDLTs). The number of DDLT performed on each day was compared with the other days of the week.

RESULTS

It was apparent that there were fewer DDLTs on Mondays, as shown by the numbers of DDLT performed on different days of the week in an ascending order: Monday 18 (7.6%), Sunday 30 (12.7%), Thursday 34 (14.3%), Friday 36 (15.2%), Wednesday 38 (16.0%), Tuesday 40 (16.9%), and Saturday 41 (17.3%). The difference reached statistical significance when Monday was compared with Tuesday (P=0.019), Wednesday (P=0.010), Friday (P=0.021), and Saturday (P=0.007). It was twice as unlikely a DDLT would be performed on Monday as compared with other days. Such a trend did not change even with an increase in the number of deceased-donor liver grafts in the last year. As consent to donation was obtained from the donor family the day before DDLT, fewer consents were thus obtained on Sundays.

CONCLUSION

These findings suggested that deceased-donor organ donation activities were less active on Sundays and could be improved. This further raises the concern of possible wastage of potential cases of organ donation.

Prioritization for liver transplantation

There are three possible policies for prioritization for liver transplantation: medical urgency, utility and transplant benefit. The first is based on the severity of cirrhosis, using Child-Turcotte-Pugh score and, more recently, the Model for End-stage Liver Disease (MELD) score, or variants of MELD, for allocation. Although prospectively developed and validated, the MELD score has several limitations, including interlaboratory variations for measurement of serum creatinine and international normalized ratio of prothrombin time, and a systematic adverse female gender bias. Adjustments to the original MELD equation and new scoring systems have been proposed to overcome these limitations; incorporation of serum sodium improves its predictive accuracy. The MELD score poorly predicts outcomes after liver transplantation due to the absence of donor factors incorporated into the scoring system. Several utility models are based on donor and recipient characteristics. Combined poor recipient and donor characteristics lead to very poor outcomes, which in a utility system would be considered unacceptable. Finally, transplant benefit models rank patients according to the net survival benefit that they would derive from transplantation. However, complex statistical models are required, and unmeasured characteristics may unduly affect the models. Well-designed prospective studies and simulation models are necessary to establish the optimal allocation system in liver transplantation.

Model for end-stage liver disease exceptions committee activity in Argentina: does it provide justice and equity among adult patients waiting for a liver transplant?

BACKGROUND

In 2005, the model of end-stage liver disease (MELD)-based allocation system was adopted to assess potential liver transplant (LT) recipients in Argentina. The aim of the present study was to revise the activity of the MELD Exception Experts Committee.

METHODS

Between 2005 and 2009, 1623 patients were listed for LT. Regulation provides extra-MELD points for amyloidosis, hepatopulmonary syndrome (HPS) and T(2) hepatocellular carcinoma (T(2) HCC). Centres could also request priority for other situations. Using a prospective database, we identified patients in whom priority points were requested. Pathology reports of explanted livers were analysed for patients with T(2) HCC.

RESULTS

From 234 out of 1623 (14.4%) requests, the overall approval rate was 60.2% including: 2 amyloidosis, 6 HPS, 111 T(2) HCC and 22 non-regulated situations. Of the 111 patients with T(2) HCC, 6 died (5.4%), 8 had tumour progression (7.2%), 94 were transplanted (84.2%) and 3 are still waiting. An explants correlation showed that presumed diagnosis of T(2) HCC was incorrect in 20/94 (22%) and was correct in only 41/94 (43%) cases being T(1) HCC in 9 and T(3) HCC in 23.

CONCLUSIONS

MELD exceptions are frequently requested in Argentina. Unfortunately, most receiving priority points for T(2) HCC benefited by medical error or imaging limitations. An intense review process is urgently needed to maintain equity and justice in the allocation system.

What is the real gain after liver transplantation?

1. For most liver allograft recipients, both the quality and length of life are greatly improved after transplantation. However, neither the quality of life nor the length of life in the survivors returns to that seen in age-matched and sex-matched normal subjects. 2. The gain in survival after transplantation can be estimated by a comparison of the actual outcome after transplantation and the predicted survival in the absence of transplantation. 3. The reduction in graft and patient survival, in comparison with a normal age-matched and sex-matched population, is determined by several factors: short-term survival is affected by the patient's condition pre-transplant and the quality of the graft, and for longer term survival, recurrent disease accounts for most of the differences seen between different indications. Some of the causes of premature death (such as infection, de novo malignancy, and cardiovascular and cerebrovascular disease) that are increased in the liver allograft recipient may be reduced by improved management with more aggressive surveillance and treatment. 4. The aims of selection and allocation vary in different health care systems: transparency, objectivity, equity of access, justice, mortality awaiting transplantation, utility, and transplant benefit are all important but often competing demands. Understanding the associated increase in survival will allow for a rational approach to this complex area.