Tag Archives: MELD

EXCEPTIONal Outcomes and Liver Allocation

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A recent study (Hepatology 2015; 61: 285 & editorial 28-31) takes a closer look at US liver organ allocation and outcomes.

The editorial notes that our allocation in the US is targeted towards “need.” Since February 2001, the MELD score was adopted with “the stated aim of reducing deaths on the waiting list.”  Other potential aims:

  • Equity –so any one who might benefit from a graft has an equal chance and a first-come, first-served approach is adopted
  • Utility –organs are allocated to the recipient who is likely to have the best outcomes
  • Benefit –organs are allocated to the patient who has the greatest benefit, so taking into account the risks of dying with and without a transplant
  • Fairness — ‘an ill-defined combination of all the approaches’

The editorial notes that “despite the concerns the approach has been highly effective in achieving its goal in reducing waiting list mortality.”

“Like any system, it can be manipulated and, given the life-saving nature of transplantation, it is scarcely surprising that both legal and illegal methods have been adopted to artificially raise the MELD score and distort allocation.”

The study reviewed 78,595 adult liver transplant candidates (2005-2012).  27.3% of the waiting list was occupied by candidates with exceptions.

Candidates with exceptions fared much better on the waiting list compared to those without exceptions in mean days waiting (HCC 237 versus non-HCC 426), transplantation rates (HCC 79.1% versus non-HCC 40.6%), and waiting list death rate (HCC 4.5% versus non-HCC 24.6%).

The editorialists recommend that “we should consider diverting some of the resources used to develop and implement a perfect allocation scheme into increasing the number of donors and livers used for transplant and, in the longer term, finding treatments and interventions that will render liver transplantation a treatment of historic interest.”  Now that’s a lofty goal.

Related blog posts:

 

It is a Question of Fairness

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One of my professors in medical school frequently described ethical issues in terms of some things being unfair and some things being unfortunate.  A report in this month’s Liver Transplantation (2013: 19: 1330-42; editorial 1287-88) indicates that sometimes an individual does not receive a liver transplant due to an unfair allocation policy.  One potential problem with the current UNOS distribution is the use of exception points.  Because the Model for End-Stage Liver Disease (MELD) score does not work well for all patients, there are both recognized exceptional diagnoses (REDs) (eg. hepatocellular carcinoma) and non-REDs (eg. cholangitis).  The purpose of these exception points is to account for some conditions that may increase the risk of dying on the transplant list in which the MELD score is not an adequate predictor.

In this study of adult liver transplant candidates between 2002-2011, the authors examined non-REDs; among a cohort of 58,641, 7.4% applied for a non-RED.  The number of non-REDs increased over the course of the study.  In addition, approval rates which were <50% in 2002 increased to nearly 75% in 2010. Candidates with approved exceptions were more likely to undergo transplantation (68.3% vs. 53.4%, P <0.001).

There was significant variability among transplant centers with regard to requesting exception points. Centers with higher median MELD score at transplantation were more likely to have candidates with non-RED applications. The net result was that women, African-Americans, Hispanics, and patients with Medicaid insurance were statistically less likely to have an exception application.

In pediatrics, non-RED applications are more common. Thus, the problem of equitable distribution could be even greater among pediatric patients.

Bottomline: While physicians have a duty to their patients, it is vital to make sure that every effort is made to allocate organs in a fair manner.  Since the use of non-RED applications is inconsistent, it suggests that some transplant centers are utilizing this tool inappropriately (?too often, ?too few).  This report indicates that more work is needed to have a fair transplant allocation system.

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Geographic Inequity for Liver Transplantation

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Organ scarcity remains a big problem for liver transplantation.  Use of the Model for End-Stage Liver Disease (MELD) score was intended to address inequity in liver transplantation allocation.  However, it has not been successful.  One recent study which examines donation after cardiac death versus brain death (Liver Transpl 2012; 18: 630-40) also yields some insight into liver transplantation allocation across the U.S.

In Figure 3, the thirty-day probability of receiving a liver transplantation (brain death donation) for patients with MELD score >20 was compared across UNOS regions.  In regions 3 and 11 (Southeastern U.S. extending to Kentucky and Virginia), the rate was ≥40%.  In region 1 (Northeastern U.S) and region 5 (Southewestern U.S.) , the rates were 9.6% and 11.8% respectively.  Thus, some patients with the exact same MELD score have a 4-fold higher probability of receiving a liver transplant.

Related blogs:

Alive and well? 10 years after liver transplantation

Picking winners and losers with liver transplantation allocation

Big gift, how much risk

Sarcopenia, fatigue, and nutrition in chronic liver disease

Picking winners and losers with liver transplantation allocation

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From a pediatric hepatology viewpoint, I’ve always been concerned that scoring systems  do not favor children.  More data is now available relevant to this topic:

  • Goldberg et al. Liver Transplantation 2012; 18: 434-43, editorial: 381-83 
  • Sepulveda et al. Liver Transplantation 2012; 18: 413-422, editorial: 389-90

These articles and the editorials look at the model for end-stage liver disease (MELD) and exceptions for hepatocellular carcinoma (HCC) as well as the issue of split livers to expand the donor pool.

The goals of liver transplantation allocation is to distribute livers to  minimize waiting list mortality, to distribute this valuable resource fairly, and to improve long-term outcomes.  How are we doing?

With regard to HCC, the authors indicate that the current policy is increasing the number of individuals transplanted with this indication.  Before MELD, 4.6% of all transplants were for candidates with HCC.  Between 2002-2007, the number increased to 26%.  This has dramatically improved the outcomes in this previously almost universally fatal disease.

But is the priority afforded by MELD priority unfair?  From 2005-2009, Goldberg et al show that the rate of individuals with HCC removed from the waiting list because of death or disease progression was much lower than non-HCC patients: 4.2% vs. 11% (90-day waitlist outcome).  Patients with HCC with exception points were 2.62 times less likely to die by waiting.  Thus, the authors conclude that allocating 22 MELD points to HCC patients greatly overestimates 90-day mortality.  Other conditions that receive 22 MELD points include candidates with hepatopulmonary syndrome, cholangiocarcinoma, cystic fibrosis, familial amyloidotic polyneuropathy, and portopulmonary syndrome.

Sepulveda et al performed a retrospective review of the experience from split liver transplantation in French adults.  In their cohort of 36 patients who received extended right grafts from split livers, there were increased complications.  Only 21 patients had a relatively easy postoperative course.  Six patients required retransplantation.  Overall survival rate was 84.2% and 77.7% at 1 and 5 years.  Complications were related to ischemia of hepatic segment 4.

In the editorial, Riccardo Superina makes several important points:

  • Many centers have equivalent outcomes for whole and split livers; there is likely a learning curve to improve technique.
  • In the U.S., between 2002-2009, only 288 split livers grafts were performed in adults whereas there were >29,000 whole liver transplants performed.
  • In the U.S. children have the highest mortality rates on the waiting list.  In 2008, 18% of children died without a chance for liver transplantation.
  • In France, allocation policy dictates that livers from all donors less than 30 years old should be directed to children first with the stipulation of liver splitting.  If this policy were adopted in US, it could alleviate the organ shortage for children who are currently most disadvantaged by UNOS (United Network for Organ Sharing) allocation policy.

Related blog posts:

Big gift, how much risk

Sarcopenia, fatigue, and nutrition in chronic liver disease

A liver disease tsunami

Additional references:

  • -Am J Transplant 2010; 10: 1643-48.  HCC patients advantaged with current allocation
  • -Clin Gastro & Hep 2008; 6: 1255. solutble TNF receptor 75 better at predicting mortality risk than MELD>
  • -Gastroenterology 2008; 135: 1568. MELD has changed allocation -less-ill patients now getting higher risk organs.
  • -Liver Transplantation 2006; 12: S128-S136. Guidelines for exceptions (increased status)
  • -Liver Transplantation 2006; 12: 12-15, 40-45. 53% of pediatric livers allocated based on other factors (eg. exception, status 1) than PELD score
  • -Gastroenterology 2003;124: 91-96, 251. MELD scores works fairly well in adults; factors in bilirubin, INR, creatinine.

GCSF for acute-on-chronic liver failure

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When chronic liver patients decompensate, there are a number of considerations, including concerns about spontaneous bacterial peritonitis, GI bleeding, and renal insufficiency.  A new study looks at another treatment to improve the outcome of these patients.  Consecutive patients with acute-on-chronic liver failure (ACLF) were randomly assigned to granulocyte colony-stimulating factor (GCSF) therapy (n=23), 5 μg/kg subcutaneously, or placebo (n=24) (Gastroenterology 2012; 142: 505-12).

The average age in this study was 40 years with the most common etiology being liver disease related to alcohol. The GCSF group, treated with 12 doses over 1 month, had higher leukocyte and platelet counts at 1 week.  More importantly, at day 60, the GCSF had higher survival, 70% vs 29%.  In addition, therapy was associated with lower Child-Turcotte-Pugh (CTP), model for end-stage liver disease (MELD) and sequential organ failure assessment (SOFA) scores.

GCSF has been shown to improve results in animal models and has been used in chronic liver disease.  The mechanism for improvement following GCSF is not clear.  One role could be in the prevention of sepsis due to increased neutrophils; patients on GCSF had less multi-organ failure which is often precipitated by sepsis.  Another factor could be an element of hepatic regeneration induced by GCSF.  It was noted that CD34 cell population increased in the liver tissue after 4 weeks of GCSF protocol.

Additional reference:

  • -Dig Liver Dis 2007; 39: 1071-76.  Use of GCSF for 5 days was not effective for acute -on-liver disease