Liver allocation and distribution: time for a change

Machine perfusion strategies in liver transplantation: A systematic review, pairwise, and network meta-analysis of randomized controlled trials

Machine perfusion (MP), including hypothermic oxygenated machine perfusion (HOPE), dual HOPE, normothermic machine perfusion (NMP), NMP ischemia-free liver transplantation (NMP-ILT), and controlled oxygenated rewarming (COR), is increasingly being investigated to improve liver graft quality from extended criteria donors and donors after circulatory death and expand the donor pool. This network meta-analysis investigates the comparative efficacy and safety of various liver MP strategies versus traditional static cold storage (SCS). We searched PubMed, Scopus, Web of Science, and Cochrane Controlled Register of Trials for randomized controlled trials comparing liver transplantation outcomes between SCS and MP techniques. The primary outcome was the incidence of early allograft dysfunction. Secondary endpoints included 1-year graft survival, the incidence of graft failure/loss, post-reperfusion syndrome, biliary complications, the need for renal replacement therapy, graft-related patient mortality, and the length of intensive care unit and hospital stay. R-software was used to conduct a network meta-analysis using a frequentist framework (PROSPERO ID: CRD42024549254). We included 12 randomized controlled trials involving 1628 patients undergoing liver transplantation (801 in the liver MP groups and 832 in the SCS group). Compared to SCS, HOPE/dHOPE, but not other MP strategies, was associated with a significantly lower risk of early allograft dysfunction (RR: 0.53, 95% CI [0.37, 0.74], p =0.0002), improved 1-year graft survival rate (RR: 1.07, 95% CI [1.01, 1.14], p =0.02), decreased graft failure/loss (RR: 0.38, 95% CI [0.16, 0.90], p =0.03), and reduced the risk of biliary complications (RR: 0.52, 95% CI [0.43, 0.75], p < 0.0001). Compared to SCS, NMP (RR: 0.49, 95% CI [0.24, 0.96]) and NMP-ILT (RR: 0.15, 95% CI [0.04, 0.57]), both significantly reduced the risk of postperfusion syndrome. There is no difference between SCS and MP groups in the risk of renal replacement therapy, graft-related patient mortality, and intensive care unit and hospital stay length. Our meta-analysis showed that HOPE/dual-HOPE is a promising alternative to SCS for donor liver preservation. These new techniques can help expand the donor pool with similar or even better post-liver transplantation outcomes.

Inconsistent values and algorithmic fairness: a review of organ allocation priority systems in the United States

BACKGROUND

The Organ Procurement and Transplant Network (OPTN) Final Rule guides national organ transplantation policies, mandating equitable organ allocation and organ-specific priority stratification systems. Current allocation scores rely on mortality predictions.

METHODS

We examined the alignment between the ethical priorities across organ prioritization systems and the statistical design of the risk models in question. We searched PubMed for literature on organ allocation history, policy, and ethics in the United States.

RESULTS

We identified 127 relevant articles, covering kidney (19), liver (60), lung (24), and heart transplants (23), and transplant accessibility (1). Current risk scores emphasize model performance and overlook ethical concerns in variable selection. The inclusion of race, sex, and geographical limits as categorical variables lacks biological basis; therefore, blurring the line between evidence-based models and discrimination. Comprehensive ethical and equity evaluation of risk scores is lacking, with only limited discussion of the algorithmic fairness of the Model for End-Stage Liver Disease (MELD) and the Kidney Donor Risk Index (KDRI) in some literature. We uncovered the inconsistent ethical standards underlying organ allocation scores in the United States. Specifically, we highlighted the exception points in MELD, the inclusion of race in KDRI, the geographical limit in the Lung Allocation Score, and the inadequacy of risk stratification in the Heart Tier system, creating obstacles for medically underserved populations.

CONCLUSIONS

We encourage efforts to address statistical and ethical concerns in organ allocation models and urge standardization and transparency in policy development to ensure fairness, equitability, and evidence-based risk predictions.

Immunosuppressive Induction Therapy Using the Antithymocyteglobulin Grafalon: A Single-Center Non-Interventional Study

Background: Induction therapy with depleting antibodies in the setting of liver transplantation (LT) is discussed controversially to this day. The rabbit antithymocyteglobulin (ATG) Thymoglobulin (rATG) was introduced as early as 1984 and was frequently used as a standard regime for induction therapy after LT. There are no public reports characterizing Grafalon (ATG-F), a novel ATG, as an induction agent after LT. Objectives: The aim of this observational non-interventional study was to investigate the safety and efficacy of Grafalon induction therapy and characterize its clinical effects in the setting of LT. Methods: A cohort of 80 patients undergoing deceased donor LT at the Medical University of Vienna and receiving Grafalon as part of the clinical standard immunosuppressive regimen was prospectively included between March 2021 and November 2022. Patients were monitored closely for leukocytopenia and thrombocytopenia during the first postoperative week and followed up for incidence and severity of biopsy-proven acute rejection (BPAR), overall survival, and bacterial infections in the first year after LT. Results: The incidences of thrombocytopenia and leukocytopenia following Grafalon treatment peaked on postoperative day four, with 64% and 31%, respectively. However, there were no cases of severe leukocytopenia after the first postoperative week. Induction therapy with Grafalon resulted in a rate of localized bacterial infections and bacteremia of 28% and 21%, respectively. The rate of BPAR was 12.5% in the first year after LT; the one-year survival rate in this cohort was 90%. Conclusions: Overall, this study provides evidence of the safety and efficacy of Grafalon as an induction agent. Further studies investigating the potential long-term effects of Grafalon, as well as comparison studies with different immunosuppressive regimens, are needed in order to draw further conclusions.

Regional Social Vulnerability is Associated With Geographic Disparity in Waitlist Outcomes for Patients With Non-Hepatocellular Carcinoma Model for End-stage Liver Disease Exceptions in the United States

OBJECTIVE

This study was undertaken to evaluate the role of regional social vulnerability in geographic disparity for patients listed for liver transplantation with non-hepatocellular carcinoma (HCC) model for end-stage liver disease (MELD) exceptions.

SUMMARY AND BACKGROUND

Prior work has demonstrated regional variability in the appropriateness of MELD exceptions for diagnoses other than HCC.

METHODS

Adults listed at a single center for first-time liver-only transplantation without HCC after June 18, 2013 in the Scientific Registry of Transplant Recipients database as of March 2021 were examined. Candidates were mapped to hospital referral regions (HRRs). Adjusted likelihood of mortality and liver transplantation were modeled. Advantaged HRRs were defined as those where exception patients were more likely to be transplanted, yet no more likely to die in adjusted analysis. The Centers for Disease Control's Social Vulnerability Index (SVI) was used as the measure for community health. Higher SVIs indicate poorer community health.

RESULTS

There were 49,494 candidates in the cohort, of whom 4337 (8.8%) had MELD exceptions. Among continental US HRRs, 27.3% (n = 78) were identified as advantaged. The mean SVI of advantaged HRRs was 0.42 versus 0.53 in nonadvantaged HRRs ( P = 0.002), indicating better community health in these areas. Only 25.3% of advantaged HRRs were in spatial clusters of high SVI versus 40.7% of nonadvantaged HRRs, whereas 44.6% of advantaged HRRs were in spatial clusters of low SVI versus 38.0% of nonadvantaged HRRs ( P = 0.037).

CONCLUSIONS

An advantage for non-HCC MELD exception patients is associated with lower social vulnerability on a population level. These findings suggest assigning similar waitlist priority to all non-HCC exception candidates without considering geographic differences in social determinants of health may actually exacerbate rather than ameliorate disparity.

County-level Differences in Liver-related Mortality, Waitlisting, and Liver Transplantation in the United States

BACKGROUND

Much of our understanding regarding geographic issues in transplantation is based on statistical techniques that do not formally account for geography and is based on obsolete boundaries such as donation service area.

METHODS

We applied spatial epidemiological techniques to analyze liver-related mortality and access to liver transplant services at the county level using data from the Centers for Disease Control and Prevention and Scientific Registry of Transplant Recipients from 2010 to 2018.

RESULTS

There was a significant negative spatial correlation between transplant rates and liver-related mortality at the county level (Moran's I, -0.319; P  = 0.001). Significant clusters were identified with high transplant rates and low liver-related mortality. Counties in geographic clusters with high ratios of liver transplants to liver-related deaths had more liver transplant centers within 150 nautical miles (6.7 versus 3.6 centers; P  < 0.001) compared with all other counties, as did counties in geographic clusters with high ratios of waitlist additions to liver-related deaths (8.5 versus 2.5 centers; P  < 0.001). The spatial correlation between waitlist mortality and overall liver-related mortality was positive (Moran's I, 0.060; P  = 0.001) but weaker. Several areas with high waitlist mortality had some of the lowest overall liver-related mortality in the country.

CONCLUSIONS

These data suggest that high waitlist mortality and allocation model for end-stage liver disease do not necessarily correlate with decreased access to transplant, whereas local transplant center density is associated with better access to waitlisting and transplant.

Dynamic impact of liver allocation policy change on donor utilization

Liver allocation policy was changed to reduce variance in median MELD scores at transplant (MMaT) in February 2020. "Acuity circles" replaced local allocation. Understanding the impact of policy change on donor utilization is important. Ideal (I), standard (S), and non-ideal (NI) donors were defined. NI donors include older, higher BMI donors with elevated transaminases or bilirubin, history of hepatitis B or C, and all DCD donors. Utilization of I, S, and NI donors was established before and after allocation change and compared between low MELD (LM) centers (MMaT ≤ 28 before allocation change) and high MELD (HM) centers (MMaT > 28). Following reallocation, transplant volume increased nationally (67 transplants/center/year pre, 74 post, p .0006) and increased for both HM and LM centers. LM centers significantly increased use of NI donors and HM centers significantly increased use of I and S donors. Centers further stratify based on donor utilization phenotype. A subset of centers increased transplant volume despite rising MMaT by broadening organ acceptance criteria, increasing use of all donor types including DCD donors (98% increase), increasing living donation, and transplanting more frequently for alcohol associated liver disease. Variance in donor utilization can undermine intended effects of allocation policy change.

Early outcomes of implanting larger-sized grafts in deceased donor liver transplantation

BACKGROUND

The outcomes of large-sized graft mismatch in deceased donor liver transplantation (LT) have been rarely studied. The aim of this study was to determine whether a large-sized graft for recipient influenced the post-transplant outcomes.

METHODS

A total of 273 patients undergoing LT were enrolled and divided into a large and a normal-sized graft group by graft weight to recipient weight (GWRW) >2.5% (n = 76) or GWRW ≤2.5% (n = 197). Post-operative complications and outcomes were retrospectively analysed.

RESULTS

The two groups were comparable in demographic characteristics. The rate of complications was significantly higher in the large-sized graft group including early allograft dysfunction (36.8% versus 17.8%, P = 0.001), hepatic necrosis (26.3% versus 13.7%, P = 0.01) and massive hydrothorax (25% versus 14.7%, P = 0.04). The large-sized graft group suffered higher early mortality compared with the normal-sized graft group (30 days: 14.5% versus 5.6%, P = 0.02, 90 days: 21.1% versus 9.6%, P = 0.01). The primary causes of early death were multiple organ failure (10.5% versus 2%, P = 0.002) and sepsis (2.6% versus 1.5%, P = 0.54). Four parameters including donor alanine transaminase, GWRW, estimated blood loss and model for end-stage liver disease score were significant on multivariate analysis, and indicated significant risk factors for the early mortality of recipients.

CONCLUSION

In deceased donor LT, GWRW >2.5% is associated with increased liver injury, risk of early mortality and other adverse outcomes. Thus, donor livers should be allocated to recipients with GWRW ≤2.5%.

Quantifying Sex-Based Disparities in Liver Allocation

Importance

Differences in local organ supply and demand have introduced geographic inequities in the Model for End-stage Liver Disease (MELD) score-based liver allocation system, prompting national debate and patient-initiated lawsuits. No study to our knowledge has quantified the sex disparities in allocation associated with clinical vs geographic characteristics.

Objective

To estimate the proportion of sex disparity in wait list mortality and deceased donor liver transplant (DDLT) associated with clinical and geographic characteristics.

Design, Setting, and Participants

This retrospective cohort study used adult (age ≥18 years) liver-only transplant listings reported to the Organ Procurement and Transplantation Network from June 18, 2013, through March 1, 2018.

Exposure

Liver transplant waiting list.

Main Outcomes and Measures

Primary outcomes included wait list mortality and DDLT. Multivariate Cox proportional hazards regression models were constructed, and inverse odds ratio weighting was used to estimate the proportion of disparity across geographic location, MELD score, and candidate anthropometric and liver measurements.

Results

Among 81 357 adults wait-listed for liver transplant only, 36.1% were women (mean [SD] age, 54.7 [11.3] years; interquartile range, 49.0-63.0 years) and 63.9% were men (mean [SD] age, 55.7 [10.1] years; interquartile range, 51.0-63.0 years). Compared with men, women were 8.6% more likely to die while on the waiting list (adjusted hazard ratio [aHR], 1.11; 95% CI, 1.04-1.18) and were 14.4% less likely to receive a DDLT (aHR, 0.86; 95% CI, 0.84-0.88). In the geographic domain, organ procurement organization was the only variable that was significantly associated with increased disparity between female sex and wait list mortality (22.1% increase; aHR, 1.22; 95% CI, 1.09-1.30); no measure of the geographic domain was associated with DDLT. Laboratory and allocation MELD scores were associated with increases in disparities in wait list mortality: 1.14 (95% CI, 1.09-1.19; 50.1% increase among women) and DDLT: 0.87 (95% CI, 0.86-0.88; 10.3% increase among women). Candidate anthropometric and liver measurements had the strongest association with disparities between men and women in wait list mortality (125.8% increase among women) and DDLT (49.0% increase among women).

Conclusions and Relevance

Our findings suggest that addressing geographic disparities alone may not mitigate sex-based disparities, which were associated with the inability of the MELD score to accurately estimate disease severity in women and to account for candidate anthropometric and liver measurements in this study.

Disparities in utilization of services for racial and ethnic minorities with hepatocellular carcinoma associated with hepatitis C

BACKGROUND

Hepatitis C affects racial minorities disproportionately and is greatest among the black population. The incidence of hepatocellular carcinoma has increased with the largest increase observed in black and Hispanic populations, but limited data remain on whether hepatitis C hepatocellular carcinoma in racial-ethnic minorities have the same utilization of services compared with the white population.

METHODS

We used the database of the National Inpatient Sample to identify hepatitis C-hepatocellular carcinoma patients (N = 200,163) who underwent liver transplantation (n = 11,491), liver resection (n = 4,896), or ablation of liver lesions (n = 6,933) from 2005 to 2015. We estimated utilization over time and assessed differences in utilization and inpatient mortality across patient characteristics.

RESULTS

In multivariate analysis, factors associated with utilization of services included treatment year, sex, race, insurance status, hospital type, and comorbidity burden, with black and Hispanic patients having statistically significantly decreased utilization. Factors associated with inpatient mortality included treatment year, sex, race, insurance status, hospital type, hospital region, and comorbidity burden, with black patients having a statistically significantly greater risk of inpatient mortality.

CONCLUSION

We identified racial and socioeconomic factors which were associated with utilization of services and inpatient mortality for patients with hepatitis C hepatocellular carcinoma. Blacks were especially disadvantaged in the receipt of care. Further work to abrogate these findings is imperative to ensure equitable provision of surgical therapies.

Basic principles of liver allocation and development over the years

PURPOSE OF REVIEW

Prior to the enactment of the National Organ Transplant Act in 1984, there was no organized system to allocate donor organs in the United States. The process of liver allocation has come a long way since then, including the development and implementation of the Model for End-stage Liver Disease, which is an objective estimate of risk of mortality among candidates awaiting liver transplantation.

RECENT FINDINGS

The Liver Transplant Community is constantly working to optimize the distribution and allocation of scare organs, which is essential to promote equitable access to a life-saving procedure in the setting of clinical advances in the treatment of liver disease. Over the past 17 years, many changes have been made. Most recently, liver distribution changed such that deceased donor livers will be distributed based on units established by geographic circles around a donor hospital rather than the current policy, which uses donor service areas as the unit of distribution. In addition, a National Liver Review Board was created to standardize the process of determining liver transplant priority for candidates with exceptional medical conditions. The aim of these changes is to allocate and distribute organs in an efficient and equitable fashion.

SUMMARY

The current review provides a historical perspective of liver allocation and the changing landscape in the United States.

Geographic Disparities in Liver Allocation and Distribution in the United States: Where Are We Now?

BACKGROUND

Equitable deceased donor liver allocation and distribution has remained a heated topic in transplant medicine. Despite the establishment of numerous policies, mixed reports regarding organ allocation persist.

METHODS

Patient data was obtained from the United Network for Organ Sharing liver transplant database between January 2016 and September 2017. A total of 20,190 patients were included in the analysis. Of this number, 8790 transplanted patients had a median Model for End-Stage Liver Disease (MELD) score of 25 (17-33), after a wait time of 129 (32-273) days. Patients were grouped into low MELD and high MELD regions using a score 25 as the cutoff.

RESULTS

Significant differences were noted between low and high MELD regions in ethnicity (white 77.4% vs 60.4%, Hispanic 8.1% vs 24.5%; P < .001) and highest level of education (grade school 4.8% vs 8.5%, Associate/Bachelor's degree 19% vs 15.7%, P < .001), respectively. Patients in high MELD regions were more likely to be multiply listed if they had a diagnosis of hepatocellular carcinoma (12.1% vs 15%, P = .046). Wait-list mortality (4.8% vs 6%, P < .001) and wait-list time (110 [27-238] vs 156 [42-309] days, P < .001) were greater in the high MELD regions.

CONCLUSIONS

These results highlight some of the existing disparities in the recently updated allocation and distribution policy of deceased donor livers. Our findings are consistent with previous work and support the liver distribution policy revision.

Migration of Patients for Liver Transplantation and Waitlist Outcomes

BACKGROUND & AIMS

Patients in need of liver transplantation may travel to improve their chance of receiving an organ. We evaluated factors to determine which transplant candidates travel to other regions to increase their chances of receiving a liver and effects of travel on waitlist outcomes.

METHODS

We performed a retrospective cohort study of all adult patients registered for primary deceased donor liver transplantation in the United States from January 2004 to December 2016. Zip code data were used to calculate the travel distance from a patient's residence to centers at which they were on the waitlist or received a liver transplant. Distant listing and migration were defined as placement on a waitlist and receipt of liver transplantation, respectively, outside the home transplantation region and greater than 500 miles from the home zip code. We assessed the effect of distant listing on outcomes (death and liver transplantation) and predictors of distant listing or migration using multivariable analyses.

RESULTS

There were 104,914 waitlist registrations during the study period; of these, 2930 (2.8%) pursued listing at a distant center. Of waitlist registrants, 60,985 received liver transplants, of whom 1985 (3.3%) had migrated. In a multivariable competing risk analysis in which liver transplantation was considered as a competing event, distant listing was associated with a 22% reduction in the risk of death within 1 year (subhazard ratio, 0.78; 95% CI, 0.70-0.88). Distant listing and migration were associated with non-black race, non-Medicaid payer, residence in a higher income area, and education beyond high school.

CONCLUSIONS

Placement on a liver transplant waitlist outside the home transplantation region is associated with reduced waitlist mortality and an increased probability of receiving a liver transplant. Geographic disparities in access to liver transplantation have disproportionate effects on patients who are minorities, have lower levels of education, or have public insurance.

Liver Allocation Policies in the USA: Past, Present, and the Future

Identifying the optimal allocation policy with regard to hepatocellular carcinoma has been a persistent and evolving challenge. The current criteria for LT for HCC endorsed by the United Network of Organ Sharing (UNOS) are based on the Milan Criteria: a solitary tumor < 5 cm, or maximum of three tumors ≤ 3 cm each, without vascular invasion or evidence of extrahepatic spread. Contraindications to HCC exception points include: stage 1 HCC, ruptured HCC, extrahepatic HCC, and main portal or hepatic vein HCC invasion. Based upon projected waitlist dropout rates due to tumor growth, patients with HCC are assigned MELD standardized exception points. In addition to tumor size and number, AFP levels are an important predictor of recurrence of HCC following liver transplantation. Standardized exception points for HCC patients are not awarded to patients with AFP levels > 1000 ng/mL that do not decrease to < 500 ng/mL with treatment. Appeals for MELD exception points for patients with HCC vary widely between UNOS regions, with success of nonstandardized exception point appeals varying from 3.1 to 21% between regions. In an effort to make prioritization for HCC more consistent, a national liver review board (NLRB)is being convened that will focus on developing a national guidance for assessing common requests and addressing exception points, including for HCC.

Disparities in the treatment of hepatocellular carcinoma based on geographical region are decreasing

BACKGROUND AND AIM

Geographic differences have existed in the management of hepatocellular carcinoma (HCC), and efforts to reduce regional disparities have been initiated. The aim of this study is to use the Nationwide Inpatient Sample to determine if regional disparities in the treatment of HCC continue to exist.

METHOD

A retrospective database analysis using the Nationwide Inpatient Sample was performed that included patients with a primary diagnosis of HCC. Logistic regression models were utilized to determine geographic disparities in liver decompensation, treatment, inpatient mortality, and metastatic disease.

RESULTS

This study's locational reach of 62 604 patients included 22 769 patients from the South (36%), 14 554 in the Northeast (23%), 14 041 in the West (22%), and 11 240 in the Midwest (18%). Patients who received treatment in the West were more likely to have inpatient mortality (OR 1.28, 95% CI 1.03, 1.53) than patients who received treatment in the Midwest. No significant differences were observed between rates of resection, ablation, and transarterial chemoembolization when comparing by region. Rates of liver transplantation were lower in the West compared with the Midwest (OR 0.51, 95% CI 0.29, 0.87). There was no significant difference between other regions.

CONCLUSION

Geographic disparities in the treatment of HCC are improving.

[Liver transplants and organ allocation in Brazil: from Rawls to utilitarianism]

The process of liver donations and transplants in Brazil reveals major inequalities between regions and states of the country, ranging from uptake of the organs to their transplantation. In 2006, the MELD score (Model for End-stage Liver Disease), inspired by the U.S. model and based on the principle of need, was introduced in Brazil for liver transplant allocation. However, Brazil's inequalities have partially undermined the initiative's success. Other countries have already benefited from growing discussion on the benefits of models that seek to harmonize utilitarianism and need. The current article reviews the relevant literature with a special focus on the Brazilian reality.

Risk Factors for Dropout From the Liver Transplant Waiting List of Hepatocellular Carcinoma Patients Under Locoregional Treatment

BACKGROUND

In new organ allocation policy, patients with hepatocellular carcinoma (HCC) experience a 6-month delay in being granted Model for End-Stage Liver Disease exception points. However, it may not be fair for patients at risk of early progression of HCC.

METHODS

All patients who were diagnosed as United Network for Organ Sharing (UNOS) stage 1 or 2 of HCC between January 2004 and December 2012 were included. Patients who received surgical resection or liver transplant (LT) as a primary treatment and who did not receive any treatment for HCC were excluded. Patients with baseline Model for End-Stage Liver Disease score ≥22 were also excluded because they have a higher chance of receiving LT. Patients who developed extrahepatic progression within 1 year were considered as high-risk for early recurrence after LT.

RESULTS

A total of 586 patients were included. Mean (SD) age was 59.9 (10.3) years and 409 patients (69.8%) were men. The cumulative incidence of estimated dropout was 8.9% at 6 months; size of the maximum nodule (≥3 cm) and nonachievement of complete response were independent factors. Extrahepatic progression developed in 16 patients (2.7%) within 1 year; size of the maximum nodule (4 cm) and alpha-fetoprotein level (>100 ng/mL) were independent predictors.

CONCLUSIONS

The estimated dropout rate from the waiting list within 6 months was 8.9%. Advantage points might be needed for patients with maximum nodule size ≥3 cm or those with noncomplete response. However, in patients with maximum nodule size ≥4 cm or alpha-fetoprotein level >100 ng/mL, caution is needed.

New paradigms for organ allocation and distribution in liver transplantation

PURPOSE OF REVIEW

The 'Final Rule,' issued by the Health Resources and Service Administration in 2000, mandated that liver allocation policy should be based on disease severity and probability of death, and - among other factors - should be independent of a candidate's residence or listing. As a result, the Organ Procurement Transplantation Network/United Network for Organ Sharing (UNOS) has explored policy changes addressing geographic disparities without compromising outcomes.

RECENT FINDINGS

Major paradigm shifts are underway in U.S. liver allocation policy. New hepatocellular carcinoma exception policy incorporates tumor characteristics associated with posttransplantation outcomes, whereas a National Liver Review Board will promote a standardized process for awarding exception points. Meanwhile, following extensive debate, new allocation policy aims to reduce geographic disparity by broadening sharing to the UNOS region and 150-mile circle around the donor hospital for liver transplant candidates with a calculated model for end-stage liver disease score at least 32. Unnecessary organ travel will be reduced by granting 3 'proximity points' to candidates within the same donation service area (DSA) as a liver donor or within 150 nautical miles of the donor hospital, regardless of DSA or UNOS region.

SUMMARY

This review provides an evaluation of major policy changes in liver allocation from 2016 to 2018.

Intraregional model for end-stage liver disease score variation in liver transplantation: Disparity in our own backyard

Variation in average Model for End-Stage Liver Disease (MELD) score at liver transplantation (LT) by United Network for Organ Sharing (UNOS) regions is well documented. The present study aimed to investigate MELD variation at the interregional, intraregional, and intra-donation service area (DSA) levels. Patients undergoing LT between 2015 and 2016 were obtained from the UNOS standard analysis and research file. The distribution of allocation MELD score including median, skew, and kurtosis was examined for all transplant programs. Intraregional median allocation MELD varied significantly within all 11 UNOS regions. The largest variation between programs was seen in region 5 (MELD 24.0 versus 38.5) and region 3 (MELD 20.5 versus 32.0). Regions 1, 5, and 9 had the largest proportion of programs with a highly negative skewed MELD score (50%, 57%, and 57%, respectively), whereas regions 3, 6, 10, and 11 did not have any programs with a highly negative skew. MELD score distribution was also examined in programs located in the same DSA, where no barriers exist and theoretically no significant difference in allocation should be observed. The largest DSA variation in median allocation MELD score was seen in NYRT-OP1 LiveOnNY (MELD score variation 11), AZOB-OP1 Donor Network of Arizona (MELD score variation 11), MAOB-OP1 New England Organ Bank (MELD score variation 9), and TXGC-OP1 LifeGift Organ Donation Ctr (MELD score variation 9). In conclusion, the present study demonstrates that this MELD disparity is not only present at the interregional level but can be seen within regions and even within DSAs between programs located as close as several city blocks away. Although organ availability likely accounts for a component of this disparity, the present study suggests that transplant center behavior may also play a significant role. Liver Transplantation 24 488-496 2018 AASLD.