Preliminary results of a liver allocation plan using a continuous medical severity score that de-emphasizes waiting time

Liver transplantation for urea cycle disorders in pediatric patients: a single-center experience

LT has emerged as a surgical treatment for UCDs. We hypothesize that LT can be safely and broadly utilized in the pediatric population to effectively prevent hyperammonemic crises and potentially improve neurocognitive outcomes. To determine the long-term outcomes of LT for UCDs, charts of children with UCD who underwent LT were retrospectively reviewed at an academic institution between July 2001 and May 2012. A total of 23 patients with UCD underwent LT at a mean age of 3.4 yr. Fifteen (65%) patients received a whole-liver graft, seven patients (30%) received a reduced-size graft, and one patient received a living donor graft. Mean five-yr patient survival was 100%, and allograft survival was 96%. Mean peak blood ammonia (NH(3) ) at presentation was 772 μmol/L (median 500, range 178-2969, normal <30-50). After transplantation, there were no episodes of hyperammonemia. Eleven patients were diagnosed with some degree of developmental delay before transplantation, which remained stable or improved after transplantation. Patients without developmental delay before transplantation maintained their cognitive abilities at long-term follow-up. LT was associated with the eradication of hyperammonemia, removal of dietary restrictions, and potentially improved neurocognitive development. Long-term follow-up is underway to evaluate whether LT at an early age (<1 yr) will attain improved neurodevelopmental outcomes.

Regional variability in symptom-based MELD exceptions: a response to organ shortage?

MELD (model for end-stage liver disease) exception awards affect the liver allocation process. Award rates of specific nonhepatocellular carcinoma exceptions, termed symptom-based exceptions (SBE), differ across UNOS regions. We aimed to characterize the regional variability in SBE awards and examine predictive factors for receiving a SBE in the MELD era. The OPTN liver transplant and waiting list dataset was analyzed for waiting list registrants during the MELD allocation on February 27, 2002, until November 22, 2006. Competing risks proportional hazards regression analysis was used to examine predictors for receiving a SBE in 39 169 registrants. The hazard ratios for receiving a SBE differed significantly across regions when adjusted for multiple variables including age, gender, ethnicity, physiologic MELD score, blood group, functional status, etiology of liver disease, insurer and education level. Utilization of SBE is highly significantly variable across UNOS regions, and does not correlate with organ availability as estimated by the regional mean physiologic MELD score at transplantation. Patients with Medicaid as their primary payer have a lower likelihood of receiving a SBE award, while patients with cryptogenic/NASH cirrhosis or cholestatic liver disease have a higher likelihood of receiving a SBE. Reasons for these regional and demographic disparities deserve further investigation.

Prediction of cardiac complications after liver transplantation

BACKGROUND

Orthotopic liver transplantation (OLT) stresses the cardiovascular system, and cardiac complications after OLT are common.

METHODS

Hundred ninety-seven patients (>or=40 years) who had OLT from 2002 to 2007 were reviewed to identify predictors of cardiac complications within 6 months after transplantation.

RESULTS

Median age was 56 years (40-75 years); 69% men. Reasons for OLT were hepatitis C virus (HCV) 45.5%, alcohol 22%, hepatocellular carcinoma (HCC) 8%, primary biliary cirrhosis 10%, and others 14.5%. Eighty-two patients suffered one or more cardiac complications within 6 months after OLT (pulmonary edema=61 [overt heart failure=7], arrhythmia=13, pulmonary hypertension=7, pericardial effusion=2, and right atrial thrombus=1). Cardiac causes were the leading cause of death (n=5; 23.8% of all mortality). By multivariate analysis, after adjusting for age and sex, independent predictors were adverse intraoperative cardiovascular events (adjusted odds ratio; 95% confidence interval: 5.89, 1.82-19.14), history of cardiac disease (2.42, 0.89-6.6), and i-MELD (integrated model for end-stage liver disease) score (1.08, 1.02-1.14), whereas adverse intraoperative cardiovascular events (5.73, 1.96-16.78) and i-MELD (1.07, 1.01-1.13) predicted pulmonary edema. None of the following variables predicted complications: age, sex, OLT indication, body mass index, blood pressure, alcohol and smoking history, pre-OLT investigations (chest X-ray, electrocardiogram, echocardiography, coronary angiography, pulmonary arterial pressure, and 2-methoxy isobutyl isonitrile scan), immunosuppressive treatment, or intraoperative variables (transfusion amount, cadaveric vs. living graft or cold ischemia and rewarming times).

CONCLUSIONS

Cardiac complications after OLT are common and were the leading cause of death after surgery. Adverse intraoperative cardiovascular events, previous cardiac disease, and advanced liver disease as quantified by i-MELD score predicted postoperative cardiac complications.

[Prognostic scores of cirrhosis]

Prognostic models are useful to estimate disease severity, establish expected survival in a specific situation, and calculate the risk of certain medical interventions. Of all the scores described in liver cirrhosis, those with the widest clinical applicability are the Child-Pugh classification and the model for end-stage liver disease (MELD). Although the Child-Pugh classification was used for many years to stratify patients and select those that can safely undergo liver surgery, currently this classification has been substituted by the MELD. This model uses only three simple and objective variables and has consequently become the most widely used instrument, especially to fix priorities when allocating organs in liver transplantation. Nevertheless, this model has some limitations since some indications for liver transplantation (hepatocarcinoma, metabolic diseases, etc.) and certain comorbidities in patients with cirrhosis (hepatic encephalopathy, hyponatremia, refractory ascites) are not well represented in the MELD.

Model for End-Stage Liver Disease (MELD) score and organ allocation from cadaveric donors for 198 liver transplantation procedures performed in a single center

Since February 2002, the United Network for Organ Sharing (UNOS) proposed to adopt a modified version of the Model for End-Stage Liver Disease (MELD) to assign priority on the waiting list for orthotopic liver transplantation (OLT). In this study, we evaluated the impact of MELD score on liver allocation in a single center series of 198 liver recipients (mean age of patients, 52.21+/-8.92 years), considering the relationship between clinical urgency derived from MELD score (overall MELD, 18.7+/-6.83; MELD <15 in 69 patients, MELD >or=15 in 129 patients) and geographical distribution of cadaveric donors (inside/outside Liguria Region, 125/73). The waiting time for OLT was 230+/-248 days, whereas the 3-month and 1-year patient survivals were 87.37% and 79.79%, respectively. No difference was observed for MELD score retrospectively calculated for patients who underwent OLT before February 2002 (n=71) compared with MELD score calculated for patients who received a liver thereafter (18.26+/-6.68 vs 18.94+/-6.92; P= .504). No significant difference was found in waiting time before and after adoption of MELD score (213+/-183 vs 238+/-278 days; P= .500), or by stratifying patients for MELD <15/>or=15 (225+/-234 vs 232+/-256 days; P= .851). Using the geographical distribution of donors as a grouping variable (outside vs inside Liguria Region), no significance occurred for MELD score (19.68+/-7.42 vs 18.17+/-6.42; P= .135) or waiting time (211+/-226 vs 242+/-261 days; P= .394). In our series, more OLTs were performed among sicker patients and no differences were found in the management of livers procured from cadaveric donors outside or inside Liguria Region. However, further efforts are needed to reduce the waiting time among patients with higher MELD scores.

Child-Pugh-Turcott versus Meld score for predicting survival in a retrospective cohort of black African cirrhotic patients

AIM: To compare the performance of the Child-Pugh-Turcott (CPT) score to that of the model for end-stage liver disease (MELD) score in predicting survival of a retrospective cohort of 172 Black African patients with cirrhosis on a short and mid-term basis.

METHODS: Univariate and multivariate (Cox model) analyses were used to identify factors related to mortality. Relationship between the two scores was appreciated by calculating the correlation coefficient. The Kaplan Meier method and the log rank test were used to elaborate and compare survival respectively. The Areas Under the Curves were used to compare the performance between scores at 3, 6 and 12 mo.

RESULTS: The study population comprised 172 patients, of which 68.9% were male. The mean age of the patient was 47.5 ± 13 years. Hepatitis B virus infection was the cause of cirrhosis in 70% of the cases. The overall mortality was 31.4% over 11 years of follow up. Independent factors significantly associated with mortality were: CPT score (HR = 3.3, 95% CI [1.7-6.2]) (P < 0.001) (stage C vs stage A-B); Serum creatine (HR = 2.5, 95% CI [1.4-4.3]) (P = 0.001) (Serum creatine > 1.5 mg/dL versus serum creatine < 1.5 mg/dL); MELD score (HR = 2.9, 95% CI [1.63-5.21]) (P < 0.001) (MELD > 21 vs MELD < 21). The area under the curves (AUC) that predict survival was 0.72 and 0.75 at 3 mo (P = 0.68), 0.64 and 0.62 at 6 mo (P = 0.67), 0.69 and 0.64 at 12 mo (P = 0.38) respectively for the CPT score and the MELD score.

CONCLUSION: The CPT score displays the same prognostic significance as does the MELD score in black African patients with cirrhosis. Moreover, its handling appears less cumbersome in clinical practice as compared to the latter.

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.

Public and private regulation of organ transplantation: liver allocation and the final rule

The allocation of cadaveric organs for transplantation in the United States is governed by a process of private regulation. Through the Organ Procurement and Transplantation Network (OPTN), stakeholders and public representatives determine the substantive content of allocation rules. Between 1994 and 2000 the U.S. Department of Health and Human Services conducted a rule making to define more clearly the public and private roles in the determination of organ allocation policy. Several prominent liver transplant centers that were losing market share as a result of the proliferation of transplant centers used the rule making as a vehicle for challenging the local priority for organ allocation inherent in the OPTN rules. The process leading to the final rule provides a window on the politics of organ allocation. It also facilitates an assessment of the strengths and weaknesses of private rule making. Overall, private rule making appears to be relatively effective in tapping the technical expertise and tacit knowledge of stakeholders to allow for the adaptation of rules in the face of changing technology and information. However, the particular system of representation employed may give less influence to some stakeholders than they would have in public regulatory arenas, giving them an incentive to seek public rule making as a remedy for their persistent losses within the framework of private rule making.

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.

Is MELD score sufficient to predict not only death on waiting list, but also post-transplant survival?

Model for end-stage liver disease (MELD) score has emerged as a useful tool in predicting mortality in patients awaiting liver transplantation. There is still, however, discussion as to whether further parameters could improve the sensitivity and specificity of the MELD score. From 1997 to 2003, 621 adult patients with end-stage liver disease were listed for orthotopic liver transplantation (OLT). Patients suffering from hepatoma were excluded from analysis (113 patients). The MELD score was investigated at the time of listing (MELD ON) and of coming off the list (MELD OFF). Patients who died while on the waiting list showed a significant increase in their MELD score during the waiting time (MELD ON: 21 +/- 7 vs. MELD OFF: 28 +/- 9) as well as a significantly higher MELD ON compared with patients who were transplanted (MELD ON: 16 +/- 5 vs. MELD OFF: 17 +/- 7) or removed from the waiting list (MELD ON: 16 +/- 6 vs. MELD OFF: 12 +/- 3). Multivariate analysis identified MELD ON, ascites and recurrent infection as independent risk factors for death on the waiting list (P < 0.01). MELD score was not identified as a predictor for the post-transplant survival rate. MELD score is a strong predictor for death on the waiting list, but refractory ascites and recurrent infection are independent risk factors, too.

Deaths on the liver transplant waiting list: an analysis of competing risks

The usual method of estimating survival probabilities, namely the Kaplan-Meier method, is suboptimal in the analysis of deaths on the transplant waiting list. Death, transplantation, and withdrawal from list must all be considered. In this analysis, we applied the competing risk analysis method, which allows evaluating these end points individually and simultaneously, to compare the risk of waiting list death across era, blood types, liver disease diagnosis, and severity (Model for End-stage Liver Disease; MELD). Of 861 patients registered on the waiting list at Mayo Clinic Rochester between 1990 and 1999, 657 (76%) patients underwent transplantation, 82 (10%) died while waiting, 41 (5%) withdrew from the list, and 81 (9%) patients were still waiting as of February 2002. The risk of death at 3 years was 10% by the competing risk analysis. During the study period, the median time to transplantation increased from 45 to 517 days. In univariate analyses, there was no significant difference in the risk of death by era of listing (P = .25) or blood type (P = .31), whereas the risk of death was significantly higher in patients with alcohol-induced liver disease and those with higher MELD score (P < .01). A multivariable analysis showed that after adjusting for MELD, blood type, and diagnosis, patients listed in the latter era had higher mortality. In conclusion, the competing risk analysis method is useful in estimating the risk of death among patients awaiting liver transplantation.

Liver transplant recipients mortality on the waiting list: long-term comparison to Child-Pugh classification and MELD

We sought to evaluate our experience concerning the high waiting list mortality rate for orthotopic liver transplantation (OLT) using the MELD (Model for End-Stage Liver Disease), which has been shown to predict short-term survival better than Child-Turcotte-Pugh (CTP) classification. The predominant end-stage disease was cirrhosis due to hepatitis C virus (67%), patient mean age was 36.8 years, and 72.1% were men. When the patients were included on a waiting list, the MELD score was stratified into W: 0 to 10; X: 11 to 20, and Y: 21 to 40 and the CPT as A: 5 to 6, B: 7 to 9, and C: 10 to 15. It was also observed that 77.8% of patients were on the waiting list, 16.4% underwent OLT and 5.8% had been removed. The estimated survival rate after 1 year was W = 85.4%; X = 83.3%, Y = 46.8%; A = 81.3%, B = 84.2%, C = 45.9%. Child median score was 8 +/- 1.5 (5 to 15) and the MELD was 14.7 +/- 5.1 (8 to 43). The mortality rate was 20.2%. Severe patients classified as Y or C showed greater mortality than the other groups (P <.001), but no significant difference between Y and C strata. The mortality rate was the same as in previous years.

MELD score versus conventional UNOS status in predicting short-term mortality after liver transplantation*

The Model for End-stage Liver Disease (MELD) provides a score able to predict short-term mortality in patients awaiting liver transplantation (LT). In the early 2002, United Network for Organ Sharing (UNOS) has proposed to replace the conventional statuses 3, 2B, and 2A with a modified MELD score. However, the accuracy of the MELD model to predict post-transplantation outcome is fairly elusive. In the present study we investigated the predictive value of the MELD score for short-term patient and graft mortality in comparison with conventional UNOS status. Sixty-nine patients listed at UNOS status 3 (n = 5), 2B (n = 55) or 2A (n = 9) who underwent LT were enrolled according to strict criteria. No donor-related parameters affected 3-month patient survival. Through univariate Cox regression, pretransplantation international normalized ratio (P = 0.049) and activated partial thromboplastin time (P = 0.032) were significantly associated with 3-month patient survival, although not in the subsequent multivariate analysis. The overall MELD score was 17 +/- 6.63 (median: 16, range: 4-34), increasing from UNOS Status 3 to 2A (r(2) = 0.171, P = 0.0001). No significant difference occurred in the median MELD score between patients who underwent a second LT and those who did not (P =0.458). The inter-rate agreement between UNOS status and MELD score after categorization for clinical urgency showed a fair agreement (kappa = 0.244). The 3-month patient and graft mortality was 15.94% and 20.29% respectively. The concordance statistic did not find significance between UNOS status and MELD score for 3-month patient (P = 0.283) or graft mortality (P = 0.957), although the MELD score revealed a major sensitivity for short-term patient mortality (0.637; 95%CI: 0.513-0.75). These findings suggest the need to implement MELD model accuracy for both inter-rate agreement with UNOS Status and patient outcome.

Pretransplant MELD score and post liver transplantation survival in the UK and Ireland

It has been shown that the model for end-stage liver disease (MELD) score is an accurate predictor of survival in patients with liver disease without transplantation. Four recent studies carried out in the United States have demonstrated that the MELD score obtained immediately prior to transplantation is also associated with post-transplant patient survival. Our aim was to evaluate how accurately the MELD score predicts 90-day post-transplant survival in adult patients with chronic liver disease in the UK and Ireland. The UK and Ireland Liver Transplant Audit has data on all liver transplants since 1994. We studied survival of 3838 adult patients after first elective liver transplantation according to United Network for Organ Sharing categories of their MELD scores (< or = 10, 11-18, 19-24, 25-35, > or =36). The overall survival at 90-days was 90.2%. The 90-day survival varied according to the United Network for Organ Sharing MELD categories (92.6%, 91.9%, 89.7%, 89.7%, and 70.8%, respectively; P < 0.01). Therefore, only those patients with a MELD score of 36 or higher (3% of the patients) had a survival that was markedly lower than the rest. As a consequence, the ability of the MELD score to discriminate between patients who were dead or alive was poor (c-statistic 0.58). Re-estimating the coefficients in the MELD regression model, even allowing for nonlinear relationships, did not improve its discriminatory ability. In conclusion, in the UK and Ireland the MELD score is significantly associated with post-transplant survival, but its predictive ability is poor. These results are in agreement with results found in the United States. Therefore, the most appropriate system to support patient selection for transplantation will be one that combines a pretransplant survival model (e.g., MELD score) with a properly developed post-transplant survival model.

MELD/PELD: one year later

The liver allocation policy in the United States was changed on February 27, 2002, to a continuous scale with almost no weight given to time waiting on the list. This was based on the dissatisfaction with the old categorical system and an understanding that waiting time as not a good discriminator of medical urgency. To assess the effects of this change, liver allocation results for the first 6 months of this new system (February 27, 2002, to August 30, 2002, era 2) with the corresponding 6 month period 1 year earlier (February 27, 2001, to August 30, 2001, era 1) were compared. Fewer registrations on the waiting list, fewer removals from the waiting list because of death or "too sick," and an increase in the number of cadaveric transplants under the new system were observed. Patients with hepatocellular cancer received additional priority with the new policy and there was a significant increase in the number of candidates transplanted with this diagnosis in era 2. Early posttransplant patient survival has not changed under the new system. Although there are many areas for improvement, which will be addressed in future refinements, the new US liver allocation plan has provided a more objective, patient-specific system to better rank waiting liver transplant candidates.

Liver and intestine transplantation

The most significant development in liver transplantation in the USA over the past year was the full implementation of the MELD- and PELD-based allocation policy in March 2002, which shifted emphasis from waiting time within broad medical urgency status to prioritization by risk of waiting list death. The implementation of this system has led to a decrease in pretransplant mortality without increasing post-transplant mortality, despite a higher severity of illness at the time of transplant. The trend over the last few years of rapidly increasing numbers of adult living donor liver transplants was reversed in 2002 by a decline of more than 30% in the number of these procedures. In 2002, a greater percentage of women received livers from living donors (43%) than deceased donors (34%), possibly because of size considerations. From 1993 to 2001, the waiting list increased more than sixfold, from 2902 patients to 18,047 patients. For the first time since 1993, the waiting list size decreased in 2002, dropping 6% to 16,974 candidates. The percentage of temporarily inactive liver candidates also increased from 2001, thus the net decrease in the active waiting list for 2002 was 12%. This may reflect a trend toward less pre-emptive listing practices under MELD. Intestine transplantation remains a low-volume procedure limited to a few transplant centers and is still accompanied by significant pre- and post-transplantation risks. As this procedure matures, its application may increase to include recipients at an earlier stage of their disease with better likelihood of success.

MELD score as a predictor of pretransplant and posttransplant survival in OPTN/UNOS status 1 patients

The Model for End-Stage Liver Disease (MELD) score is predictive of survival and is used to prioritize patients with chronic liver disease patients for orthotopic liver transplantation (OLT). The aims of this study are (1) to assess the ability of MELD score at listing to predict pretransplant and posttransplant survival for nonchronic liver disease patients listed with the Organ Procurement and Transplantation Network/ United Network for Organ Sharing (OPTN/UNOS) as Status 1; and (2) to compare survival associated with 4 diagnostic groups within the Status 1 designation. The study population consisted of adult patients listed for OLT at Status 1 in the UNOS national database between November 1, 1999 and March 14, 2002 (N = 720). Events within 30 days of listing were analyzed using Kaplan-Meier and Cox regression methodology. Patients meeting criteria for fulminant hepatic failure without acetaminophen toxicity (FHF-NA, n = 312) had the poorest survival probability while awaiting OLT; this was negatively correlated with MELD score (P =.0001). These patients experienced the greatest survival benefit associated with OLT, with an estimated improvement of survival from about 58% to 91% (P <.0001). Patients listed for primary nonfunction within 7 days of OLT (n = 268) did not show mortality to be related to MELD score (P =.41) and did not show a significant association between survival and OLT (P =.68). In conclusion, liver allocation within the Status 1 designation may need to be further stratified by diagnosis, and MELD score may be useful for prioritizing FHF-NA candidates.

Results of the first year of the new liver allocation plan

Liver allocation policy in the U.S. was recently changed to a continuous disease severity scale with minimal weight given to time waiting in an effort to better prioritize deceased donor liver transplant candidates. We compared rates of waiting list registrations, removals, transplants, and deaths during the year prior to implementation of the new liver allocation policy (2/27/01-2/26/02, Era 1) with the first year's experience (2/27/02-2/26/03, Era 2) under this new policy. Rates were adjusted for 1,000 patient years on the waiting list and compared using z-tests. A 1-sided test was used to compare death rates; 2-sided tests were used to compare transplant rates. Overall and subgroup analyses were performed for demographic, geographic, and medical strata. In Era 2, we observed a 12% reduction in new liver transplant waiting list registrations, with the largest reductions seen in new registrants with low MELD/PELD scores. In Era 2, there was a 3.5% reduction in waiting list death rate (P =.076) and a 10.2% increase in cadaveric transplants (P <.001). The reduction in waiting list mortality and increase in transplantation rates were evenly distributed across all demographic and medical strata, with some variation across geographic variables. Early patient and graft survival after deceased donor liver transplantation remains unchanged. In conclusion, by eliminating the categorical waiting list prioritization system that emphasized time waiting, the new system has been associated with reduced registrations and improved transplantation rates without increased mortality rates for individual groups of waiting candidates or changes in early transplant survival rates.

MELD score predicts 1-year patient survival post-orthotopic liver transplantation

The Model for End-Stage Liver Disease (MELD) is an important predictor in patients awaiting orthotopic liver transplantation (OLT). However, the model's association with posttransplant patient survival is unclear. We studied 1-year patient survival in 404 adult patients who underwent OLT at the University of California Los Angeles. The hazard rates of patient survival according to the MELD strata and United Network for Organ Sharing (UNOS) statuses were assessed by Proportional Hazard Cox regression analysis. The difference in survival for MELD strata and UNOS status were compared using the Cox model. There was a significant difference in 1-year patient (P =.0006) survival using different MELD strata, whereas there was a trend according to UNOS status (P =.051). Increased rate of death was observed in recipients of OLT with higher MELD scores (> 36, hazard ratio 3.9; 95% CI 1.55, 10.27) and more urgent UNOS status (2A; hazard ratio, 1.99; 95% CI 1.07, 3.7). The MELD stratum is better associated with 1-year patient survival in liver transplant recipients than UNOS statuses. Patient survival was worse with higher MELD scores.

Critical analysis of the allocation policy for liver transplantation in Brazil

Liver transplantation is now the standard treatment for end-stage liver disease. Given the shortage of liver donors and the progressively higher number of patients waiting for transplantation, improvements in patient selection and optimization of timing for transplantation are needed. Several solutions have been suggested, including increasing the donor pool; a fair policy for allocation, not permitting variables such as age, gender, and race, or third-party payer status to play any role; and knowledge of the natural history of each liver disease for which transplantation is offered. To observe ethical rules and distributive justice (guarantee to every citizen the same opportunity to get an organ), the "sickest first" policy must be used. Studies have demonstrated that death has no relationship with waiting time, but rather with the severity of liver disease at the time of inclusion. Thus, waiting time is no longer part of the United Network for Organ Sharing distribution criteria. Waiting time only differentiates between equally severely diseased patients. The authors have analyzed the waiting list mortality and 1-year survival for patients of the State of S o Paulo, from July 1997 through January 2001. Only the chronological criterion was used. According to "Secretaria de Estado da Saúde de São Paulo" data, among all waiting list deaths, 82.2% occurred within the first year, and 37.6% within the first 3 months following inclusion. The allocation of livers based on waiting time is neither fair nor ethical, impairs distributive justice and human rights, and does not occur in any other part of the world.

Recent advances in liver transplantation

Advances in liver transplantation continue to evolve but are hampered by continued increasing shortages in donor organs. This has resulted in a high incidence of patients dying while on the United Network for Organ Sharing waiting list. Indeed, we continue to assess ways of expanding the donor pool by using marginal donors, living donor liver transplantation, split liver transplantation, domino transplantation, and hepatic support systems to prolong survival long enough for the patient to undergo liver transplantation. Changes in the liver allocation policy to reduce the number of people dying while waiting for an organ are discussed. Implementation of the model for end-stage liver disease allocation system should help alleviate the problem of increasing deaths of patients while on the waiting list. Recurrent disease, particularly recurrent hepatitis C, continues to be a major problem, and effective therapy is needed to prevent both progression of hepatitis C and recurrence in the graft and avoid retransplantation. The use of pegylated interferon in combination with ribavirin holds promise for improving the success in overcoming recurrent hepatitis C. Finally, advances in immunosuppression have reduced the incidence of acute cellular rejection and chronic rejection. However, these therapies have been fraught with metabolic complications that are now affecting quality of life and long-term survival. Tailoring immunosuppressive regimens to the individual patient is discussed.

Model for end-stage liver disease (MELD) and allocation of donor livers

BACKGROUND & AIMS

A consensus has been reached that liver donor allocation should be based primarily on liver disease severity and that waiting time should not be a major determining factor. Our aim was to assess the capability of the Model for End-Stage Liver Disease (MELD) score to correctly rank potential liver recipients according to their severity of liver disease and mortality risk on the OPTN liver waiting list.

METHODS

The MELD model predicts liver disease severity based on serum creatinine, serum total bilirubin, and INR and has been shown to be useful in predicting mortality in patients with compensated and decompensated cirrhosis. In this study, we prospectively applied the MELD score to estimate 3-month mortality to 3437 adult liver transplant candidates with chronic liver disease who were added to the OPTN waiting list at 2A or 2B status between November, 1999, and December, 2001.

RESULTS

In this study cohort with chronic liver disease, 412 (12%) died during the 3-month follow-up period. Waiting list mortality increased directly in proportion to the listing MELD score. Patients having a MELD score <9 experienced a 1.9% mortality, whereas patients having a MELD score > or =40 had a mortality rate of 71.3%. Using the c-statistic with 3-month mortality as the end point, the area under the receiver operating characteristic (ROC) curve for the MELD score was 0.83 compared with 0.76 for the Child-Turcotte-Pugh (CTP) score (P < 0.001).

CONCLUSIONS

These data suggest that the MELD score is able to accurately predict 3-month mortality among patients with chronic liver disease on the liver waiting list and can be applied for allocation of donor livers.

Donor and recipient outcomes in right lobe adult living donor liver transplantation

Severe donor organ shortage has provided the impetus for adult living donor liver transplantation (ALDLT). Despite rapid implementation and expansion of the procedure, outcome analysis of ALDLT is still incomplete. This study analyzed both donor and recipient outcomes after ALDLT at a single center. ALDLT performed at UCLA between August 1999 and November 2001 were reviewed retrospectively. Twenty recipients (14 men and 6 women) with a mean age of 48.8 +/- 9.7 (29 to 66) years underwent right lobe ALDLT. By computed tomograpy (CT), graft/recipient weight ratio (GRWR) was 1.3 +/- 0.3 (1 to 2.2). Overall 1-year patient and graft survival rates were 95% and 85%, respectively. One recipient died of heart failure with normal liver function 5 months after transplantation. Three grafts (14%) were lost and all three patients underwent successful cadaveric retransplantation. Complications were classified according to the Clavien grading system with all but 3 recipients encountering at least one complication. Nine (45%) had grade 1 (minor), 10 (50%) had grade 2 (potentially life threatening without residual disease/disability), 3 (14%) had grade 4A (retransplantation) and one grade 4B (death). Right lobectomy for living donation was performed in 20 patients (12 men, 8 women). Residual left lobe volumes were 36 +/- 5.3 (23.9 to 47.9)% of total donor liver volume. No donor required intensive care unit admission and median hospital stay was 7.5 (6 to 14) days. One donor was aborted after intraoperative biopsy showed > 50% macrovesicular steatosis. No donor mortality or long-term complications were encountered. Five grade 1 minor complications, by Clavien Classification, occurred in 4 of 20 (20%) donors. ALDLT using right lobe grafts is an effective procedure to expand a severely depleted donor, but is associated with a high complication rate despite good survival outcomes. Continuous standardized reporting of ALDLT outcomes is required to allow successful and safe implementation of the procedure.

An examination of factors predicting prioritization for liver transplantation

With the recent transition of the liver transplant allocation system to the Model for End-Stage Liver Disease, a major change is its reliance entirely on objective criteria. In previous reports, potential donor families and members of the transplant community have questioned the fairness of the subjective nature of previous systems. Therefore, we examined the United Network for Organ Sharing database to determine if the previous allocation system benefited a particular group in prioritization for transplant. We included adult patients with chronic liver disease listed for transplant in the year 2000. Patients who had ever been listed as status 2A or 2B were analyzed. A multivariable analysis examined the patient characteristics that predicted being uplisted to status 2A. Of the 9244 patients, 2376 (25.7%) had received a liver transplant as a status 2A or had been listed as status 2A. In the multivariate analysis, the strongest patient characteristics that predicted status 2A were listing in the western United States and shorter duration of registration. Other predictors include blood type O, college education, unemployment, and coverage with private insurance or a health maintenance organization/preferred provider organization. In addition, patients with Laennec's cirrhosis were less likely to be uplisted to status 2A. Age, gender, and race were not predictors of uplisting to status 2A. In conclusion, these data show the wide range of practice patterns with the use of status 2A, and these findings suggest that certain patient groups might have received preference in the previous liver transplant allocation system.

Liver transplantation for hepatocellular carcinoma: analysis of survival according to the intention-to-treat principle and dropout from the waiting list

A major obstacle for orthotopic liver transplantation (OLT) as treatment for hepatocellular carcinoma (HCC) is tumor growth resulting in dropout from the waiting list for OLT. There is a paucity of data on survival according to intention-to-treat analysis and the rate of dropout from the waiting list for OLT among patients with HCC. To further evaluate these issues, we analyzed the outcome of 46 consecutive patients with HCC listed for OLT between January 1998 and January 2001. Exclusion criteria for OLT were tumor size greater than 5 cm for one to three lesions or four lesions or greater of any size. Twenty-one patients underwent OLT. There were 11 dropouts because of tumor progression and six deaths, including three deaths after dropout. Kaplan-Meier 1- and 2-year intention-to-treat survival rates were 91.7% and 72.6%, respectively. Monthly dropout rates were 0% from 0 to 3 months, 1.5% from 3 to 6 months, 1.0% from 6 to 9 months, 4.9% from 9 to 12 months, and 5.6% from 12 to 15 months. One dropout occurred beyond 15 months among 4 patients remaining at risk. Cumulative probabilities for dropout at 6, 12, and 24 months were 7.3%, 25.3%, and 43.6%, respectively. Predictors for dropout included two or three tumor nodules or a solitary lesion greater than 3 cm at initial presentation and previous hepatic resection. Our results support recent changes in the scheme of organ allocation aimed at reducing the dropout rate and improving outcome for patients with HCC awaiting OLT.

Pretransplant model to predict posttransplant survival in liver transplant patients

OBJECTIVE

To develop a prognostic model that determines patient survival outcomes after orthotopic liver transplantation (OLT) using readily available pretransplant variables.

SUMMARY BACKGROUND DATA

The current liver organ allocation system strongly favors organ distribution to critically ill recipients who exhibit poor survival outcomes following OLT. A severely limited organ resource, increasing waiting list deaths, and rising numbers of critically ill recipients mandate an organ allocation system that balances disease severity with survival outcomes. Such goals can be realized only through the development of prognostic models that predict survival following OLT.

METHODS

Variables that may affect patient survival following OLT were analyzed in hepatitis C (HCV) recipients at the authors' center, since HCV is the most common indication for OLT. The resulting patient survival model was examined and refined in HCV and non-HCV patients in the United Network for Organ Sharing (UNOS) database. Kaplan-Meier methods, univariate comparisons, and multivariate Cox proportional hazard regression were employed for analyses.

RESULTS

Variables identified by multivariate analysis as independent predictors for patient survival following primary transplantation of adult HCV recipients in the last 10 years at the authors' center were entered into a prognostic survival model to predict patient survival. Accordingly, mortality was predicted by 0.0293 (recipient age) + 1.085 (log10 recipient creatinine) + 0.289 (donor female gender) + 0.675 urgent UNOS - 1.612 (log10 recipient creatinine times urgent UNOS). The above variables, in addition to donor age, total bilirubin, prothrombin time (PT), retransplantation, and warm and cold ischemia times, were applied to the UNOS database. Of the 46,942 patients transplanted over the last 10 years, 25,772 patients had complete data sets. An eight-factor model that accurately predicted survival was derived. Accordingly, the mortality index posttransplantation = 0.0084 donor age + 0.019 recipient age + 0.816 log creatinine + 0.0044 warm ischemia (in minutes) + 0.659 (if second transplant) + 0.10 log bilirubin + 0.0087 PT + 0.01 cold ischemia (in hours). Thus, this model is applicable to first or second liver transplants. Patient survival rates based on model-predicted risk scores for death and observed posttransplant survival rates were similar. Additionally, the model accurately predicted survival outcomes for HCV and non-HCV patients.

CONCLUSIONS

Posttransplant patient survival can be accurately predicted based on eight straightforward factors. The balanced application of a model for liver transplant survival estimate, in addition to disease severity, as estimated by the model for end-stage liver disease, would markedly improve survival outcomes and maximize patients' benefits following OLT.

Is MELD really the definitive score for liver allocation?

The best system for organ allocation is still a controversial issue. The aim of this study was to study the accuracy of four different scores to predict mortality on the waiting list and, thus, their usefulness to determine organ allocation. We retrospectively compared two groups of patients, those who died on waiting list (group D) and those who successfully underwent transplantation (group T) during the same time period. Four scores, at the time of entering the waiting list and just before liver transplantation or death, were evaluated. The evaluated scores were as follows: (1) the Child-Pugh classification; (2) the Model for End-Stage Liver Disease (MELD) score; (3) the Freeman scale; and (4) the Guardiola et al index. The mortality rate on waiting list was 15.9%. All studied scores, except Freeman scale, were higher in group D at the time of entrance on waiting list (MELD, 17.4 +/- 8 v 12.3 +/- 6, P = .02; Child, 9.9 +/- 2 v 7.7 +/- 2, P = .002; Freeman, 9.7 +/- 4 v 7.3 +/- 3.9, P = .09; Guardiola, 2.6 +/- 0.9 v 1.7 +/- 0.7, P = .001). C-statistics of all scores were similar and in all cases lower than 0.8 (MELD, 0.75; Child, 0.78; Freeman, 0.65; Guardiola, 0.79). None of the studied scores have an excellent accuracy to predict prognosis of patients on waiting list, mainly in case of populations with high proportion of hepatocellular carcinoma. Although the MELD score is rapidly available, standardized, and objective, it does not reflect the severity of patients with cancer or metabolic disorders.

Pretransplant model to predict posttransplant survival in liver transplant patients

OBJECTIVE

To develop a prognostic model that determines patient survival outcomes after orthotopic liver transplantation (OLT) using readily available pretransplant variables.

SUMMARY BACKGROUND DATA

The current liver organ allocation system strongly favors organ distribution to critically ill recipients who exhibit poor survival outcomes following OLT. A severely limited organ resource, increasing waiting list deaths, and rising numbers of critically ill recipients mandate an organ allocation system that balances disease severity with survival outcomes. Such goals can be realized only through the development of prognostic models that predict survival following OLT.

METHODS

Variables that may affect patient survival following OLT were analyzed in hepatitis C (HCV) recipients at the authors' center, since HCV is the most common indication for OLT. The resulting patient survival model was examined and refined in HCV and non-HCV patients in the United Network for Organ Sharing (UNOS) database. Kaplan-Meier methods, univariate comparisons, and multivariate Cox proportional hazard regression were employed for analyses.

RESULTS

Variables identified by multivariate analysis as independent predictors for patient survival following primary transplantation of adult HCV recipients in the last 10 years at the authors' center were entered into a prognostic survival model to predict patient survival. Accordingly, mortality was predicted by 0.0293 (recipient age) + 1.085 (log10 recipient creatinine) + 0.289 (donor female gender) + 0.675 urgent UNOS - 1.612 (log10 recipient creatinine times urgent UNOS). The above variables, in addition to donor age, total bilirubin, prothrombin time (PT), retransplantation, and warm and cold ischemia times, were applied to the UNOS database. Of the 46,942 patients transplanted over the last 10 years, 25,772 patients had complete data sets. An eight-factor model that accurately predicted survival was derived. Accordingly, the mortality index posttransplantation = 0.0084 donor age + 0.019 recipient age + 0.816 log creatinine + 0.0044 warm ischemia (in minutes) + 0.659 (if second transplant) + 0.10 log bilirubin + 0.0087 PT + 0.01 cold ischemia (in hours). Thus, this model is applicable to first or second liver transplants. Patient survival rates based on model-predicted risk scores for death and observed posttransplant survival rates were similar. Additionally, the model accurately predicted survival outcomes for HCV and non-HCV patients.

CONCLUSIONS

Posttransplant patient survival can be accurately predicted based on eight straightforward factors. The balanced application of a model for liver transplant survival estimate, in addition to disease severity, as estimated by the model for end-stage liver disease, would markedly improve survival outcomes and maximize patients' benefits following OLT.

External validation of a prognostic model for predicting survival of cirrhotic patients with refractory ascites

OBJECTIVE

Cirrhotic patients with refractory ascites (RA) have a poor prognosis, although individual survival varies greatly. A model that could predict survival for patients with RA would be helpful in planning treatment. Moreover, in cases of potential liver transplantation, a model of these characteristics would provide the bases for establishing priorities of organ allocation and the selection of patients for a living donor graft. Recently, we developed a model to predict survival of patients with RA. The aim of this study was to establish its generalizability for predicting the survival of patients with RA.

METHODS

The model was validated by assessing its performance in an external cohort of patients with RA included in a multicenter, randomized, controlled trial that compared large-volume paracentesis and peritoneovenous shunt. The values for actual and model-predicted survival of three risk groups of patients, established according to the model, were compared graphically and by means of the one-sample log-rank test.

RESULTS

The model provided a very good fit to the survival data of the three risk groups in the validation cohort. We also found good agreement between the survival predicted from the model and the observed survival when patients treated with peritoneovenous shunt and with paracentesis were considered separately.

CONCLUSION

Our survival model can be used to predict the survival of patients with RA and may be a useful tool in clinical decision making, especially in deciding priority for liver transplantation.

The new liver allocation system: moving toward evidence-based transplantation policy

In 1999, the Institute of Medicine suggested that instituting a continuous disease severity score that de-emphasizes waiting time could improve the allocation of cadaveric livers for transplantation. This report describes the development and initial implementation of this new plan. The goal was to develop a continuous disease severity scale that uses objective, readily available variables to predict mortality risk in patients with end-stage liver disease and reduce the emphasis on waiting time. Mechanisms were also developed for inclusion of good transplant candidates who do not have high risk of death but for whom transplantation may be urgent. The Model for End-Stage Liver Disease (MELD) and Pediatric End-Stage Liver Disease (PELD) scores were selected as the basis for the new allocation policy because of their high degree of accuracy for predicting death in patients having a variety of liver disease etiologies and across a broad spectrum of liver disease severity. Except for the most urgent patients, all patients will be ranked continuously under the new policy by their MELD/PELD score. Waiting time is used only to prioritize patients with identical MELD/PELD scores. Patients who are not well served by the MELD/PELD scores can be prioritized through a regionalized peer review system. This new liver allocation plan is based on more objective, verifiable measures of disease severity with minimal emphasis on waiting time. Application of such risk models provides an evidenced-based approach on which to base further refinements and improve the model.

Redrawing organ distribution boundaries: results of a computer-simulated analysis for liver transplantation

For several years, the Organ Procurement and Transplantation Network/United Network for Organ Sharing (UNOS) Liver and Intestinal Transplantation Committee has been examining effects of changes and proposed changes to the liver allocation system. The Institute of Medicine recently recommended that the size of liver distribution units be increased to improve the organ distribution system. Methods to achieve this and the potential impact on patients and transplant centers of such a change are evaluated in this study. In hypothetical scenarios, we combined geographically contiguous organ procurement organizations (OPOs) in seven different configurations to increase the size of liver distribution units to cover populations greater than 9 million persons. Using the UNOS Liver Allocation Model (ULAM), we examined the effect of 17 different organ allocation sequences in these proposed realignments and compared them with those predicted by ULAM for the current liver distribution system by using the following primary outcome variables: number of primary liver transplantations performed, total number of deaths, and total number of life-years saved. Every proposed new liver distribution unit plan resulted in fewer primary transplantations. Many policies increased the total number of deaths and reduced total life-years saved compared with the current system. Most of the proposed plans reduced interregional variation compared with the current plan, but no one plan consistently reduced variation for all outcome variables, and all reductions in variations were relatively small. All new liver distribution unit plans led to significant shifts in the number of transplantations performed in individual OPOs compared with the current system. The ULAM predicts that changing liver distribution units to larger geographic areas has little positive impact on overall results of liver transplantation in the United States compared with the current plan. Enlarging liver distribution units likely will result in significant shifts in organs across current OPO boundaries, which will have a significant impact on the activity of many transplant centers.

Reduced use of intensive care after liver transplantation: patient attributes that determine early transfer to surgical wards

Part 1 of our report, presented in the same issue of the Journal, shows that immediate postoperative extubation and direct transfer to the surgical ward is safe and reduces reliance on the intensive care unit in most liver transplant recipients. However, there is no method to preoperatively predict which patients will need ventilatory support after surgery. To address this issue, we examined the relationship between perioperative patient attributes and extubation outcome in patients entered into our immediate postoperative extubation study from 1996 to 1998. Variables chosen stemmed from considerations in the literature. We examined the influence of 13 preoperative and 6 intraoperative factors on extubation outcome. Preoperative attributes included sex, race, diagnosis, United Network for Organ Sharing status, Child-Pugh score, presence of a portosystemic shunt, ascites, encephalopathy, coagulation, age, body mass index (BMI), creatinine level, and year of surgery. Intraoperative factors were type of surgery, surgeon, anesthesiologist, number of red blood cells administered, length of surgery, and surgical start time. Female sex (P =.02), BMI of 32 or greater (P =.015), portosystemic shunt (P =.022), and encephalopathy (P =.041) were associated with no attempt by the physician to extubate, whereas encephalopathy (P =.01) and BMI of 34 or greater (P =.002) were associated with failure to meet criteria for postoperative extubation (described in part 1 of this study). We conclude there are limited factors that predict an increased risk for postoperative respiratory failure in liver transplant recipients. Our results indicate that physicians are conservative in their approach to extubation immediately after surgery, and sole reliance on physician judgment to determine suitability for postoperative extubation leads to unnecessary use of postoperative cardiopulmonary support.

Development of a pediatric end-stage liver disease score to predict poor outcome in children awaiting liver transplantation

BACKGROUND

A pediatric end-stage liver disease (PELD) score for children with chronic liver disease using easily obtainable, objective, verifiable parameters, would be useful to prioritize children awaiting liver transplantation.

METHODS

Data from the Studies of Pediatric Liver Transplantation (SPLIT), a consortium of 29 U.S. and Canadian centers, were used to develop the PELD score. Two pretransplantation endpoints were evaluated: (1) death, n=884; and (2) death or moving to the intensive care unit (ICU), n=779. The analyses were restricted to children with chronic liver disease who were listed for a first transplant. Preliminary analyses of 17 possible factors yielded 6 parameters of interest: age <1 year, total bilirubin, international normalized ratio (INR), albumin, growth failure (height or weight Z score <-2), and calculated glomerular filtration rate. In a univariate Cox regression analysis, age, bilirubin, INR, and albumin were significant (P<0.01) predictors of both endpoints; glomerular filtration rate was not significant for either endpoint; and growth failure was significant for death/ICU but not death alone. In the multivariate analyses, age, bilirubin, and INR were significant for the death endpoint; and bilirubin, INR, growth failure, and albumin were significant for the death/ICU endpoint. From these results, three PELD models were evaluated to predict both outcomes at 3 and 6 months: PELD 1 (age, bilirubin, INR); PELD 2 (bilirubin, INR, albumin, growth failure); and PELD 3 (bilirubin, INR, albumin, growth failure, and age). The area under the receiver operating characteristic curve (AUC ROC) was used to compare models. For PELD 3, the most inclusive model, the AUC ROC at 3 months was 0.92 for death and 0.82 for "death-moved to ICU." A comparison of the AUC ROCs for the other models and for the model of end-stage liver disease ([MELD], the adult end-stage liver disease severity score model), none of which performed better than PELD 3, are presented.

CONCLUSION

A model using five objective parameters can accurately predict death or death-moved to ICU in children awaiting liver transplantation.