Liver transplant recipient selection: MELD vs. clinical judgment

Should AI allocate livers for transplant? Public attitudes and ethical considerations

BACKGROUND

Allocation of scarce organs for transplantation is ethically challenging. Artificial intelligence (AI) has been proposed to assist in liver allocation, however the ethics of this remains unexplored and the view of the public unknown. The aim of this paper was to assess public attitudes on whether AI should be used in liver allocation and how it should be implemented.

METHODS

We first introduce some potential ethical issues concerning AI in liver allocation, before analysing a pilot survey including online responses from 172 UK laypeople, recruited through Prolific Academic.

FINDINGS

Most participants found AI in liver allocation acceptable (69.2%) and would not be less likely to donate their organs if AI was used in allocation (72.7%). Respondents thought AI was more likely to be consistent and less biased compared to humans, although were concerned about the "dehumanisation of healthcare" and whether AI could consider important nuances in allocation decisions. Participants valued accuracy, impartiality, and consistency in a decision-maker, more than interpretability and empathy. Respondents were split on whether AI should be trained on previous decisions or programmed with specific objectives. Whether allocation decisions were made by transplant committee or AI, participants valued consideration of urgency, survival likelihood, life years gained, age, future medication compliance, quality of life, future alcohol use and past alcohol use. On the other hand, the majority thought the following factors were not relevant to prioritisation: past crime, future crime, future societal contribution, social disadvantage, and gender.

CONCLUSIONS

There are good reasons to use AI in liver allocation, and our sample of participants appeared to support its use. If confirmed, this support would give democratic legitimacy to the use of AI in this context and reduce the risk that donation rates could be affected negatively. Our findings on specific ethical concerns also identify potential expectations and reservations laypeople have regarding AI in this area, which can inform how AI in liver allocation could be best implemented.

THE OPTIMUM LEVEL OF MELD TO MINIMIZE THE MORTALITY ON LIVER TRANSPLANTATION WAITING LIST, AND LIVER TRANSPLANTED PATIENT IN SÃO PAULO STATE, BRAZIL

BACKGROUND

After validation in multiple types of liver disease patients, the MELD score was adopted as a standard by which liver transplant candidates with end-stage liver disease were prioritized for organ allocation in the United States since 2002, and in Brazil, since 2006.

AIMS

To analyze the mortality profile of patients on the liver transplant waiting list correlated to MELD score at the moment of transplantation.

METHODS

This study used the data from the Secretary of Health of the São Paulo State, Brazil, which listed 22,522 patients, from 2006 (when MELD score was introduced in Brazil) until June 2009. Patients with acute hepatic failure and tumors were included as well. We also considered the mortality of both non-transplanted and transplanted patients as a function of the MELD score at presentation.

RESULTS

Our model showed that the best MELD score for patients on the liver transplant waiting list associated to better results after liver transplantation was 26.

CONCLUSIONS

We found that the best score for applying to liver transplant waiting list in the State of São Paulo was 26. This is the score that minimizes the mortality in both non-transplanted and liver transplanted patients.

Hepatic Encephalopathy and Spontaneous Bacterial Peritonitis Improve Cirrhosis Outcome Prediction: A Modified Seven-Stage Model as a Clinical Alternative to MELD

Classification of cirrhosis based on clinical stages is rapid and based on five stages at present. Two other relevant events, hepatic encephalopathy (HE) and spontaneous bacterial peritonitis (SBP), can be considered in a clinical perspective but no study has implemented a seven-stage classification and confirmed its value before. In addition, long-term validation of the Model for End-Stage Liver Disease (MELD) in large cohorts of patients with cirrhosis and comparison with clinical findings are insufficient. Therefore, we performed a study to address these items. From the Chang-Gung Research Database (CGRD), 20,782 patients with cirrhosis were enrolled for an historical survival study. The MELD score, the five-stage clinical score (i.e., occurrence of esophageal varices (EV), EV bleeding, ascites, sepsis) and a novel seven-stage clinical score (i.e., occurrence of EV, EV bleeding, ascites, sepsis, HE, SBP) were compared with their Cox models by receiver operating characteristic (ROC) analysis. The addition of HE and SBP to the seven-stage model had a 5% better prediction result than the five-stage model did in the survival ROC analysis. The result showed that the seven clinical stages are associated with an increased risk for mortality. However, the predicted performances of the seven-stage model and MELD system are likely equivalent. In conclusion, the study (i) proved that clinical staging of cirrhosis based on seven items/stages had higher prognostic value than the five-stage model and (ii) confirmed the validity of the MELD criteria vs. clinical assessment.

Systematic Review and Meta-Analysis of Tacrolimus versus Ciclosporin as Primary Immunosuppression After Liver Transplant

Background and Aims

Several meta-analyses comparing ciclosporin with tacrolimus have been conducted since the 1994 publication of the tacrolimus registration trials, but most captured data from randomized controlled trials (RCTs) predating recent improvements in waiting list prioritization, induction protocols and concomitant medications. The present study comprised a systematic review and meta-analysis of ciclosporin and tacrolimus in liver transplant recipients using studies published since January 2000.

Methods

Searches of PubMed, the Cochrane Library and EMBASE identified RCTs of tacrolimus and ciclosporin as the immunosuppressant in adult primary liver transplant recipients, published between January 2000 and August 6, 2014. A random effects meta-analysis was conducted to evaluate the relative risk of death, graft loss, acute rejection (AR), new-onset diabetes after transplantation (NODAT) and hypertension with tacrolimus relative to ciclosporin at 12 months.

Results

The literature search identified 11 RCTs comparing ciclosporin with tacrolimus. Relative to ciclosporin, tacrolimus was associated with significantly improved outcomes in terms of patient mortality (risk ratio [RR] with ciclosporin of 1.26; 95% confidence interval [95%CI] 1.01–1.58). Tacrolimus was superior to ciclosporin in terms of hypertension (RR with ciclosporin 1.26; 95%CI 1.07–1.47), but inferior in terms of NODAT (RR with ciclosporin 0.60; 95%CI 0.47–0.77). There were no significant differences between ciclosporin and tacrolimus in terms of graft loss or AR.

Conclusions

Meta-analysis of RCTs published since 2000 showed tacrolimus to be superior to ciclosporin in terms of patient mortality and hypertension, while ciclosporin was superior in terms of NODAT. No significant differences were identified in terms of graft loss or AR. These findings provide further evidence supporting the use of tacrolimus as the cornerstone of immunosuppressive therapy in liver transplant recipients.

Hepatic encephalopathy expands the predictivity of model for end-stage liver disease in liver transplant setting: Evidence by means of 2 independent cohorts

Despite its documented prognostic relevance, hepatic encephalopathy (HE) is not considered in liver transplantation (LT) due to its possible poor objectivity. To override this problem, we aimed to analyze if an objective diagnosis of HE may confer additional mortality risk beyond MELD. Study and validation cohorts of patients with cirrhosis were considered in Italy and Canada, respectively. Patients were considered to be HE+ if an episode of overt HE was documented in a hospitalization. Of the 486 patients enrolled in Italy, 184 (38%) were HE+. During the 6-month follow-up, 77 patients died and 50 underwent transplantation. The 6-month mortality of HE+ versus HE- patients was significantly higher (P < 0.001). Model for End-Stage Liver Disease (MELD; subdistribution hazard ratio [sHR], 1.2; 95% confidence interval [CI], 1.1-1.2; P < 0.001), HE+ (sHR, 3.6; 95% CI, 1.8-7.1; P < 0.001), and sodium (sHR, 0.9; 95% CI, 0.8-0.9; P < 0.001) were independent predictors of 6-month mortality. In HE+ patients, short-term mortality increased across the entire MELD spectrum (range, 6-40). The results were unchanged by including or excluding patients with hepatocellular carcinoma or stratifying patients according to HE characteristics. The higher 6-month mortality of HE+ versus HE- patients was confirmed also in the Canadian cohort (P < 0.001; n = 300, 33% HE+; 33 died, 104 transplanted). A similar and statistically significant C-index increase derived by the incorporation of HE in MELD was observed both in the Italian (from 0.67 to 0.75) and Canadian (from 0.69 to 0.74) cohorts. A score based on MELD plus 7 points (95% CI, 4-10) for HE+ patients optimally predicted 6-month mortality in the 2 cohorts. According to the net reclassification index, by not considering HE, 29% of overall patients were misclassified by MELD score. In conclusion, the incorporation of HE in MELD score might improve the listing and allocation policy in LT. Liver Transplantation 22 1333-1342 2016 AASLD.

Model for end-stage liver disease score and MELD exceptions: 15 years later

The model for end-stage liver disease (MELD) score has been used as an objective scale of disease severity for management of patients with end-stage liver disease; it currently serves as the basis of an urgency-based organ-allocation policy in several countries. Implementation of the MELD score led to a reduction in waiting-list registration and waiting-list mortality and an increase in the number of deceased-donor transplants without adversely affecting long-term outcomes after liver transplantation (LT). The MELD score has been used for management of non-transplant patients with chronic liver disease. MELD exceptions serve as a mechanism to advance the needs of subsets of patients with liver disease not adequately addressed by MELD-based organ allocation. Several models have been proposed to refine and improve the MELD score as the environment within which it operates continues to evolve toward transplantation for sicker patients. The MELD score continues to serve and be used as a template to improve upon as an objective gauge of disease severity and as a metric enabling optimization of allocation of scarce donor organs for LT.

Nutritional status and liver transplantation

Chronic liver disease has a profound effect on nutritional status and undernourishment is almost universally present in patients with end-stage liver disease undergoing liver transplantation. In the last decades, due to epidemiological changes, a trend showing an increase in patients with end-stage liver disease and associated obesity has also been reported in developed countries. Nutrition abnormalities may influence the outcome after transplantation therefore, the importance to carefully assess the nutritional status in the work-up of patients candidates for liver transplantation is widely accepted. More attention has been given to malnourished patients as they represent the greater number. The subjective global nutritional assessment and anthropometric measurements are recognized in current guidelines to be adequate in identifying those patients at risk of malnutrition. Cirrhotic patients with a depletion in lean body mass and fat deposits have an increased surgical risk and malnutrition may impact on morbidity, mortality and costs in the post-transplantation setting. For this reason an adequate calorie and protein intake should always be ensured to malnourished cirrhotic patient either through the diet, or using oral nutritional supplements or by enteral or parenteral nutrition although studies supporting the efficacy of nutritional supplementation in improving the clinical outcomes after transplantation are still scarce. When liver function is restored, an amelioration in the nutritional status is expected. After liver transplantation in fact dietary intake rapidly normalizes and fat mass is progressively regained while the recovery of muscle mass can be slower. In some patients unregulated weight gain may lead to over-nutrition and may favor metabolic disorders (hypertension, hyperglycemia, hyperlipidemia). This condition, defined as 'metabolic syndrome', may play a negative role on the overall survival of liver transplant patients. In this report we review data on nutrition and liver transplantation.

Model for end-stage liver disease: end of the first decade

The Model for End-stage Liver Disease (MELD) score is the basis for allocation of liver allografts for transplantation in the United States. The MELD score, as an objective scale of disease severity, is also used in the management of patients with chronic liver disease in the nontransplant setting. Several models have been proposed to improve the MELD score. The authors believe that the MELD score is, by design, continually evolving and lends itself to continued refinement and improvement to serve as a metric to optimize organ allocation in the future.

Risk factors for long-term mortality in a large cohort of patients wait-listed for liver transplantation in Brazil

Liver donor shortage and long waiting times are observed in many liver transplant programs worldwide. The aim of this study was to evaluate the wait list in a developing country, before and after the introduction of the MELD scoring system. In addition, the MELD score ability to predict mortality in this setting was assessed. A single-center retrospective study of patients wait-listed for liver transplantation between 1997 and 2010 was undertaken. There were 1339 and 762 patients on the list in pre-MELD and MELD era, respectively. A competitive risk analysis was performed to assess age, gender, disease diagnosis, serum sodium, MELD, Child-Pugh, ABO type, and body mass index. Also, MELD score predictive ability at 3, 6, 12, and 24 months after list enrollment was evaluated. The overall mortality rates on waiting list were 31.0% and 28.1% (P = 0.16), and the median waiting times were 412 and 952 days (P < 0.001), in pre and MELD eras, respectively. The competitive risk analysis yielded the following significant P values for both eras: HCC (0.03 and <0.001), MELD (<0.001 and 0.002), sodium level (0.002 and <0.001), and Child-Pugh (0.02 and <0.001). The MELD mortality predictions at 3, 6, 12, and 24 months were similar. In conclusion, in a liver transplant program with long waiting times, the MELD system introduction did not improve mortality rate. In either pre and MELD eras, HCC diagnosis, serum sodium, Child-Pugh, and MELD were significant predictors of prognosis. Short- and long-term MELD based mortality predictions were similarly accurate. Strategies for increasing the liver donor pool should be implemented to improve mortality.

The effect of changes of model for end-stage liver disease score during waiting time on post-liver transplant mortality

OBJECTIVE

Model for End-Stage Liver Disease (MELD) score is found to be a robust predictor of mortality while on waiting list for liver transplantation. However, studies have shown inconsistent results for transplant MELD as a predictor of posttransplant mortality.

AIM

To find whether utilization of MELD at listing, at transplant, or Δ MELD while waiting can predict outcome at a national transplant center, which is not part of an organ sharing network.

METHOD

Retrospective analysis of patients listed for liver transplantation at the New Zealand Liver Transplant Unit (NZLTU) with calculation of MELD score at the time of listing and at transplant with/without adjustment points for hepatocellular carcinoma (HCC).

RESULTS

Between 1998 and 2005, 264 adult patients were listed for liver transplantation. Median age at transplant was 49 years (range 16-70) and 65% were male. The most common etiology was viral hepatitis (50%). A total of 48 patients (20%) had known HCC. MELD scores (adjusted and nonadjusted) at listing and at transplantation were similar across all primary liver diseases (P = 0.88, 0.93, respectively). Adjusted MELD scores were significantly higher in patients listed for HCC compared to those without HCC (P < 0.001; hazard ratio 1.33; 95% confidence interval = 1.21-1.46). MELD scores at transplant did not correlate with either 3 or 12 months mortality (P = 0.336, 0.228, respectively). This finding was consistent whether the change of MELD during waiting time was >1 point or less (P = 0.67). Waiting time does not appear to influence posttransplant survival (P = 0.75).

CONCLUSION

In a country with a single transplant center and organ retrieval organization, the addition of MELD score to current minimal listing criteria does not improve prioritization of patients on the waiting list or predict posttransplant survival. Also, adjusting MELD score for HCC would unfairly disadvantage patients listed without HCC.

The MELD score in patients awaiting liver transplant: strengths and weaknesses

Adoption of the Model for End-stage Liver Disease (MELD) to select and prioritize patients for liver transplantation represented a turning point in organ allocation. Prioritization of transplant recipients switched from time accrued on the waiting list to the principle of "sickest first". The MELD score incorporates three simple laboratory parameters (serum creatinine and bilirubin, and INR for prothrombin time) and stratifies patients according to their disease severity in an objective and continuous ranking scale. Concordance statistics have demonstrated its high accuracy in stratifying patients according to their risk of dying in the short-term (three months). Further validations of MELD as a predictor of survival at various temporal end-points have been obtained in independent patient cohorts with a broad spectrum of chronic liver disease. The MELD-based liver graft allocation policy has led to a reduction in waitlist new registrations and mortality, shorter waiting times, and an increase in transplants, without altering overall graft and patient survival rates after transplantation. MELD limitations are related either to the inter-laboratory variability of the parameters included in the score, or to the inability of the formula to predict mortality accurately in specific settings. For some conditions, such as hepatocellular carcinoma, widely accepted MELD corrections have been devised. For others, such as persistent ascites and hyponatremia, attempts to improve MELD's predicting power are currently underway, but await definite validation.

A revised model for end-stage liver disease optimizes prediction of mortality among patients awaiting liver transplantation

BACKGROUND & AIMS

The Model for End Stage Liver Disease (MELD) was originally developed based on data from patients who underwent the transjugular intrahepatic portosystemic shunt procedure. An updated MELD based on data from patients awaiting liver transplantation should improve mortality prediction and allocation efficiency.

METHODS

Wait-list data from adult primary liver transplantation candidates from the Organ Procurement and Transplantation Network were divided into a model derivation set (2005-2006; n=14,214) and validation set (2007-2008; n=13,945). Cox regression analysis was used to derive and validate an optimized model that updated coefficients and upper and lower bounds for MELD components and included serum levels of sodium. Main outcomes measure was ability to predict 90-day mortality of patients on the liver transplantation wait list.

RESULTS

Optimized MELD score updated coefficients and implemented new upper and lower bounds for creatinine (0.8 and 3.0 mg/dL, respectively) and international normalized ratio (1 and 3, respectively). Serum sodium concentrations significantly predicted mortality, even after adjusting for the updated MELD model. The final model, based on updated fit of the 4 variables (ie, bilirubin, creatinine, international normalized ratio, and sodium) had a modest yet statistically significant gain in discrimination (concordance: 0.878 vs 0.865; P<.01) in the validation dataset. Utilization of the new score could affect up to 12% of patients (based on changed score for 459 of 3981 transplants in the validation set).

CONCLUSIONS

Modification of MELD score to update coefficients, change upper and lower bounds, and incorporate serum sodium levels improved wait-list mortality prediction and should increase efficiency of allocation of donated livers.

Survival tree and MELD to predict long term survival in liver transplantation waiting list

MELD score is a formula based on laboratory variables used as a predictor of short-term mortality index in cirrhotic patients. It is applied to allocate patients in liver transplantation waiting list in many countries. However, MELD score cutoff point accuracy to predict long term mortality has not been statistically evaluated. The aim of this study was to analyze the MELD score and other variables related to long-term mortality using a new model: the Survival Tree analysis. The variables considered in this study were obtained at the time of liver transplantation list enrollment. The graphical representation of the survival trees showed that MELD 16 was the most statistically significant mortality cutoff point. The results were compatible with the MELD cutoff point reported in the clinical literature. This methodology can be extended to identify significant cutoff points related to other diseases whose severity is not necessarily expressed by MELD.

Major adverse events, pretransplant assessment and outcome prediction

Liver cirrhosis and portal hypertension pose enormous loss of lives and resources throughout the world, especially in endemic areas of chronic viral hepatitis. Although the pathophysiology of cirrhosis is not completely understood, the accumulating evidence has paved the way for better control of the complications, including gastroesophageal variceal bleeding, hepatic encephalopathy, ascites, hepatorenal syndrome, hepatopulmonary syndrome and portopulmonary hypertension. Modern pharmacological and interventional therapies have been designed to treat these complications. However, liver transplantation (LT) is the only definite treatment for patients with preterminal end-stage liver disease. To pursue successful LT, the meticulous evaluation of potential recipients and donors is pivotal, especially for living donor transplantation. The critical shortage of cadaveric donor livers is another concern. In many Asian countries, cultural and religious concerns further limit the number of the donors, which lags far behind that of the recipients. The model for end-stage liver disease (MELD) scoring system has recently become the prevailing criterion for organ allocation. Initial results showed clear benefits of moving from the Child-Turcotte-Pugh-based system toward the MELD-based organ allocation system. In addition to the MELD, serum sodium is another important prognostic predictor in patients with advanced cirrhosis. The incorporation of serum sodium into the MELD could enhance the performance of the MELD and could become an indispensable strategy in refining the priority for LT. However, the feasibility of the MELD in combination with sodium in predicting the outcome for patients on transplant waiting list awaits actual outcome data before this becomes standard practice in the Asia-Pacific region.

[The application of MELD score in patients submitted to liver transplantation: a retrospective analysis of survival and the predictive factors in the short and long term]

BACKGROUND

The model for end-stage liver disease (MELD) was developed to predict short-term mortality in patients with cirrhosis. There are few reports studying the correlation between MELD and long-term posttransplantation survival.

AIM

To assess the value of pretransplant MELD in the prediction of posttransplant survival.

METHODS

The adult patients (age >18 years) who underwent liver transplantation were examined in a retrospective longitudinal cohort of patients, through the prospective data base. We excluded acute liver failure, retransplantation and reduced or split-livers. The liver donors were evaluated according to: age, sex, weight, creatinine, bilirubin, sodium, aspartate aminotransferase, personal antecedents, brain death cause, steatosis, expanded criteria donor number and index donor risk. The recipients' data were: sex, age, weight, chronic hepatic disease, Child-Turcotte-Pugh points, pretransplant and initial MELD score, pretransplant creatinine clearance, sodium, cold and warm ischemia times, hospital length of stay, blood requirements, and alanine aminotransferase (ALT >1,000 UI/L = liver dysfunction). The Kaplan-Meier method with the log-rank test was used for the univariable analyses of posttransplant patient survival. For the multivariable analyses the Cox proportional hazard regression method with the stepwise procedure was used with stratifying sodium and MELD as variables. ROC curve was used to define area under the curve for MELD and Child-Turcotte-Pugh.

RESULTS

A total of 232 patients with 10 years follow up were available. The MELD cutoff was 20 and Child-Turcotte-Pugh cutoff was 11.5. For MELD score > or =20, the risk factors for death were: red cell requirements, liver dysfunction and donor's sodium. For the patients with hyponatremia the risk factors were: negative delta-MELD score, red cell requirements, liver dysfunction and donor's sodium. The regression univariated analyses came up with the following risk factors for death: score MELD > or = 25, blood requirements, recipient creatinine clearance pretransplant and age donor > or =50. After stepwise analyses, only red cell requirement was predictive. Patients with MELD score < 25 had a 68.86%, 50,44% and 41,50% chance for 1, 5 and 10-year survival and > or =25 were 39.13%, 29.81% and 22.36% respectively. Patients without hyponatremia were 65.16%, 50.28% and 41,98% and with hyponatremia 44.44%, 34.28% and 28.57% respectively. Patients with IDR > or =1.7 showed 53.7%, 27.71% and 13.85% and index donor risk <1.7 was 63.62%, 51.4% and 44.08%, respectively. Age donor > 50 years showed 38.4%, 26.21% and 13.1% and age donor < or =50 years showed 65.58%, 26.21% and 13.1%. Association with delta-MELD score did not show any significant difference. Expanded criteria donors were associated with primary non-function and severe liver dysfunction. Predictive factors for death were blood requirements, hyponatremia, liver dysfunction and donor's sodium.

CONCLUSION

In conclusion MELD over 25, recipient's hyponatremia, blood requirements, donor's sodium were associated with poor survival.

[The value of MELD in the allocation of priority for liver transplantation candidates]

Liver transplantation is the most effective treatment for many patients with chronic end-stage liver disease. The discrepancy between the number of donor organs and potential recipients causes marked pre-transplantation mortality and consequently optimal rationalization of organ allocation is essential. The Model for End-Stage Liver Disease (MELD) is an objective and easily reproducible prognostic index of mortality based on three simple analytical variables: bilirubin and serum creatinine and the prothrombin time/International Normalized Ratio (INR) of protrombine time. The implementation of MELD as an organ allocation system has reduced mortality on the waiting list without affecting post-transplantation survival. Nevertheless, this model has some limitations and consequently further investigations should be performed to improve the organ allocation policy in liver transplantation.

The impact of MELD allocation on simultaneous liver-kidney transplantation

Model for End-Stage Liver Disease (MELD) allocation has improved the process for ranking patients on the liver transplant list. One unintended consequence has been an increase in the number of simultaneous liver-kidney (SLK) transplants. Some have argued that the system unfairly advantages patients with kidney disease and that some kidneys are being prematurely placed in SLK transplantation. This review summarizes the MELD score, assessment of kidney function in cirrhosis, the impact of kidney function in liver disease, and changes in kidney function status in liver transplant recipients in the MELD era. Finally, recommendations regarding who should receive SLK transplants are reviewed.

Technical complications in organ procurement

It is of crucial importance that harvested organs are not discarded because of lesions inflicted during the procurement operation. From January 2005 to January 2006, a total of 395 organs were procured: 266 kidneys, 102 livers, and 27 pancreas. Two kidneys were lost due to vascular lesions, and 1 liver could not be transplanted because of a severe parenchymal injury (0.75% total organ losses). In 33 of 198 cases (16.7%) despite lesions to renal vessels or to the ureter, the kidneys were transplanted after back-table repair procedures. Vascular lesions were observed in 10% of the evaluated livers (8 of 102) and in 3 of 18 pancreatic grafts. In the literature, a total organ loss of 0.75% because of technical problems demonstrates a high standard of visceral organ procurement in our region. Hence, reparable vascular and ureteral lesions in 10% to 16.4% indicated the need for better surgical training and standardization in procurement techniques. We believe that double-checking both the organ and quality reports and giving immediate feedback to the procurement surgeons in cases of technical problems are effective ways to perform quality control. It must be our goal to increase the response rate of the quality forms.

The model for end-stage liver disease comes of age

The care of patients who have chronic liver disease has evolved considerably since the Model for End-stage Liver Disease (MELD) was first described 6 years ago. This article traces the progress in liver allocation and clinical liver disease research that includes the MELD score and highlights the management of areas in which MELD and the principles underlying MELD enhance the clinician's ability to understand better the patient who has chronic liver disease.

The model for end-stage liver disease (MELD)

The Model for End-stage Liver Disease (MELD) was initially created to predict survival in patients with complications of portal hypertension undergoing elective placement of transjugular intrahepatic portosystemic shunts. The MELD which uses only objective variables was validated subsequently as an accurate predictor of survival among different populations of patients with advanced liver disease. The major use of the MELD score has been in allocation of organs for liver transplantation. However, the MELD score has also been shown to predict survival in patients with cirrhosis who have infections, variceal bleeding, as well as in patients with fulminant hepatic failure and alcoholic hepatitis. MELD may be used in selection of patients for surgery other than liver transplantation and in determining optimal treatment for patients with hepatocellular carcinoma who are not candidates for liver transplantation. Despite the many advantages of the MELD score, there are approximately 15%-20% of patients whose survival cannot be accurately predicted by the MELD score. It is possible that the addition of variables that are better determinants of liver and renal function may improve the predictive accuracy of the model. Efforts at further refinement and validation of the MELD score will continue.

Risk factors for liver transplantation waiting list mortality

BACKGROUND AND AIM

The gap between the demand for liver transplantation and organ donation rates has a major impact on waiting list mortality. Understanding the risk factors that predict liver transplant waiting list death may help optimize organ allocation policy and reduce waiting list deaths.

METHODS

We analyzed risk factors associated with waiting list mortality in the Liver Transplant Unit Victoria for the period 1988 through 2004.

RESULTS

The mean annual waiting list mortality for the period examined was 10.2% (10.6% for adult and 6.4% for pediatric patients). Factors associated with waiting list death included female sex, fulminant hepatic failure, primary non-function, blood group O, more urgent United Network for Organ Sharing (UNOS)-derived medical status, a Child-Turcotte-Pugh (CTP) score >or=11, a model for end-stage liver disease (MELD) score >or=20, and a pediatric end-stage liver disease score >or=20. UNOS-derived medical status, CTP class, and MELD score were significant at the multivariate level.

CONCLUSIONS

Disease severity scores, such as MELD, predict the risk of liver transplantation waiting list mortality. Use of such scores in organ allocation in Australian liver transplant units may result in reduced waiting list mortality.