Changes in liver acceptance patterns after implementation of Share 35

Assessing LSAM's ability to account for changes in organ donation and transplant center behavior

The Liver Simulated Allocation Model (LSAM) is used to evaluate proposed organ allocation policies. Although LSAM has been shown to predict the directionality of changes in transplants and nonused organs, the magnitude is often overestimated. One reason is that policymakers and researchers using LSAM assume static levels of organ donation and center behavior because of challenges with predicting future behavior. We sought to assess the ability of LSAM to account for changes in organ donation and organ acceptance behavior using LSAM 2019. We ran 1-year simulations with the default model and then ran simulations changing donor arrival rates (ie, organ donation) and center acceptance behavior. Changing the donor arrival rate was associated with a progressive simulated increase in transplants, with corresponding simulated decreases in waitlist deaths. Changing parameters related to organ acceptance was associated with important changes in transplants, nonused organs, and waitlist deaths in the expected direction in data simulations, although to a much lesser degree than changing the donor arrival rate. Increasing the donor arrival rate was associated with a marked decrease in the travel distance of donor livers in simulations. In conclusion, we demonstrate that LSAM can account for changes in organ donation and organ acceptance in a manner aligned with historical precedent that can inform future policy analyses. As Scientific Registry of Transplant Recipients develops new simulation programs, the importance of considering changes in donation and center practice is critical to accurately estimate the impact of new allocation policies.

Liver Transplantation in Acute-on-Chronic Liver Failure

In recent years there has been a significant increase in the incidence of acute-on-chronic liver failure (ACLF). This syndrome is characterized by infections, organ failures, and high short-term mortality. Although progress in the management of these sick patients has been evident, liver transplantation (LT) remains the best treatment modality to date. Several studies have reported LT as a feasible option, despite organ failures. The outcomes following LT are inversely related to the grade of ACLF. This review discusses the current literature on the feasibility, futility, timing, and outcomes of LT in patients with ACLF.

Understanding the Final Disposition of Livers Declined After the Start of Procurement: A Nationwide Organ Procurement Organization Effort

Declining a liver offer during organ procurement likely increases the risk of discard, but the specifics around late reallocation remain obscure. This voluntarily submitted, prospectively collected data describe late declines and the ultimate disposition of 893 livers. Once a liver suffered an intraoperative decline, only 49% of recovered livers were transplanted. Livers declined ≥80 minutes prior to cross-clamp were transplanted 80% of the time versus livers declined ≥80 minutes after cross-clamp, which were transplanted 45% of the time. The final disposition of these livers was into a predetermined backup patient (51%) or required an out-of-sequence expedited allocation (42%). Prerecovery imaging and prerecovery biopsy did not influence the ability to reallocate a liver, and livers from donors after circulatory death are rarely successfully reallocated. In conclusion, this study begins to shed light on this seemingly common practice. A total of 85% of centers had an intraoperative decline, but 4% of centers accounted for 25% of the declines. Organ procurement organizations often enter expedited liver allocation, and instituting a cross-clamp delay to allow for reallocation may influence the disposition of these liver grafts. Expedited allocation was more time consuming than allocation into a predetermined backup. Although a certain number of intraoperative declines probably suggests a healthy amount of donor selection aggressiveness at the time of the initial organ offer, the 47% risk of discard of livers declined intraoperatively suggests that United Network for Organ Sharing should consider systematically collecting data about intraoperative declines so we can learn more about this event that influences organ utilization.

Geographic disparities in liver supply/demand ratio within fixed-distance and fixed-population circles

Recent OPTN proposals to address geographic disparity in liver allocation have involved circular boundaries: the policy selected 12/17 allocated to 150-mile circles in addition to DSAs/regions, and the policy selected 12/18 allocated to 150-mile circles eliminating DSA/region boundaries. However, methods to reduce geographic disparity remain controversial, within the OPTN and the transplant community. To inform ongoing discussions, we studied center-level supply/demand ratios using SRTR data (07/2013-06/2017) for 27 334 transplanted deceased donor livers and 44 652 incident waitlist candidates. Supply was the number of donors from an allocation unit (DSA or circle), allocated proportionally (by waitlist size) to the centers drawing on these donors. We measured geographic disparity as variance in log-transformed supply/demand ratio, comparing allocation based on DSAs, fixed-distance circles (150- or 400-mile radius), and fixed-population (12- or 50-million) circles. The recently proposed 150-mile radius circles (variance = 0.11, P = .9) or 12-million-population circles (variance = 0.08, P = .1) did not reduce the geographic disparity compared to DSA-based allocation (variance = 0.11). However, geographic disparity decreased substantially to 0.02 in both larger fixed-distance (400-mile, P < .001) and larger fixed-population (50-million, P < .001) circles (P = .9 comparing fixed distance and fixed population). For allocation circles to reduce geographic disparities, they must be larger than a 150-mile radius; additionally, fixed-population circles are not superior to fixed-distance circles.

Deceased Pediatric Donor Livers: How Current Policy Drives Allocation and Transplantation

Each year, approximately 60 children, representing 12% of waitlist candidates, die awaiting liver transplantation. The current allocation algorithm for pediatric donor livers prioritizes local/regional adults over national children. We attempted to better understand the impact of the present algorithm on pediatric candidates. We analyzed pediatric donor liver offers from 2010 to 2014. Donors and recipients were classified based on age. We mapped allocation and acceptance patterns and used subgroup analyses to explore the significance of donor service areas (DSAs) with low pediatric transplant volumes. We used Cox proportional hazard regressions to evaluate posttransplantation outcomes: 3,318 pediatric donor livers were transplanted into 3,482 recipients, and 45% (1,569) were adults. Of the 1,569 adults, 25% (390) received a pediatric organ that was never offered to children; 52% (204) of these 390 pediatric organs originated in the 37 DSAs, with ≤25 pediatric liver transplantations; 278 children died or were delisted due to illness during the same time, with higher mortality rates in the 37 DSAs (10% versus 6%, P < 0.01). Compared to adults, pediatric recipients aged <12 years had lower risks of posttransplant mortality (hazard ratio, 0.62; 95% confidence interval, 0.46-0.81; P < 0.01). Conclusions: We found that 45% of pediatric donor livers were transplanted into adults: 390 adults were transplanted with pediatric organs never offered to children, while 278 children died or were delisted due to illness, which was more apparent in DSAs with low pediatric transplant volumes; we advocate for a change to allocation policies to allow pediatric organs to be offered to national children with status 1B or Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease >15 before being offered to local/regional + circle non-status 1A adults.

The Impact of Share 35 Policy on Patient Survival in Patients Undergoing Liver Transplantation With Gender- and Race-Mismatched Donors: An Analysis of the United Network for Organ Sharing Registry

INTRODUCTION

The United Network for Organ Sharing (UNOS) instituted the Share 35 policy in June 2013 in order to reduce death on liver transplant waitlist. The effect of this policy on patient survival among patients with gender- and race-mismatched donors has not been examined.

RESEARCH QUESTION

To assess the impact of Share 35 policy on posttransplantation patient survival among patients with end-stage liver disease (ESLD) transplanted with gender- and race-mismatched donors.

DESIGN

A total of 16 467 adult patients with ESLD who underwent liver transplantation between 2012 and 2015 were identified from UNOS. An overall Cox proportional hazards model adjusting for demographic, clinical, and geographic factors and separate models with a dummy variable of pre- and post-Share 35 periods as well as its interaction with other factors were performed to model the effect of gender and race mismatch on posttransplantation patient survival and to compare the patient survival differences between the first 18 months of Share 35 policy to an equivalent time period before.

RESULTS

Comparison of the pre- and post-Share 35 periods did not show significant changes in the numbers of gender- and race-mismatched transplants, or the risk of death for gender-mismatched recipients. However, black recipients with Hispanic donors (hazard ratio: 0.51, 95% confidence interval, 0.29-0.90) had significantly increased patient survival after Share 35 policy took effect.

CONCLUSION

The Share 35 policy had a moderate impact on posttransplantation patient survival among recipients with racially mismatched donors according to the first 18-month experience. Future research is recommended to explore long-term transplantation.

Geographic variation in liver transplantation persists despite implementation of Share35

AIM

Geographic disparities persist in the USA despite locoregional organ sharing policies. The impact of national organ sharing policies on waiting-list mortality on a regional basis remains unknown.

METHODS

Data on all adult liver transplants between 1 February 2002 and 31 March 2015 were obtained from the United Network for Organ Sharing/Organ and Transplantation Network. Multivariable Cox proportional hazards models were constructed in a time-to-event analysis to estimate waiting-list mortality for the pre- and post-Share35 eras.

RESULTS

In the analyzed time period, 134 247 patients were listed for transplantation and 54 510 received organs (42.8%). Listing volume increased following the introduction of the Share35 organ sharing policy (15 976 candidates pre- vs. 18 375 post) without significant regional changes as did the number of transplants (7210 pre- vs. 8224 post). Waiting-list mortality improved from 12.2% to 8.1% (P < 0.001). Adjusted waiting-list mortality ratios remained geographically disparate. Region 10 and region 11 had lower hazard ratios (HR) but still had increased mortality (1.46, 95% confidence interval [CI] 1.34-1.60, P < 0.001; and HR 1.49, 95% CI 1.37-1.62, P < 0.001, respectively). Regions 3 and 6 had increased HR with persistently elevated waiting-list mortality (1.79, 95% CI 1.66-1.93, P < 0.001; and HR 1.29, 95% CI 1.16-1.45, P < 0.001, respectively). Model for End-state Liver Disease (MELD) exception continued to propagate a survival benefit (HR 0.65, 95% CI 0.63-0.68, P < 0.001).

CONCLUSIONS

Although overall waiting-list mortality has decreased, geographic disparities persist, but appear reduced despite broader sharing policies enacted by Share35. The advantage afforded by MELD exception, while still present, was diminished by Share35 as organs are being shifted to MELD >35 candidates. The disparities highlighted by our findings imply a need to review current allocation policies to best balance local, regional, and national transplant environments.

Improved posttransplant mortality after share 35 for liver transplantation

The Share 35 policy was implemented in June 2013 to improve equity in access to liver transplantation (LT) between patients with fulminant liver failure and those with cirrhosis and severe hepatic decompensation. The aim of this study was to assess post-LT outcomes after Share 35. Relevant donor, procurement, and recipient data were extracted from the Organ Procurement and Transplantation Network/United Network for Organ Sharing database. All adult deceased donor LTs from January 1, 2010, to March 31, 2016, were included in the analysis. One-year patient survival before and after Share 35 was assessed by multivariable Cox proportional hazards analysis, with adjustment for variables known to affect graft survival. Of 34,975 adult LT recipients, 16,472 (47.1%) were transplanted after the implementation of Share 35, of whom 4,599 (27.9%) had a Model for End-Stage Liver Disease (MELD) score ≥35. One-year patient survival improved from 83.9% to 88.4% after Share 35 (P < 0.01) for patients with MELD ≥35. There was no significant impact on survival of patients with MELD <35 (P = 0.69). Quality of donor organs, as measured by a donor risk index without the regional share component, improved for patients with MELD ≥35 (P < 0.01) and worsened for patients with lower MELD (P < 0.01). In multivariable Cox regression analysis, Share 35 was associated with improved 1-year patient survival (hazard ratio, 0.69; 95% confidence interval, 0.60-0.80) in recipients with MELD ≥35.

CONCLUSION

Share 35 has had a positive impact on survival after transplantation in patients with MELD ≥35, without a reciprocal detriment in patients with lower acuity; this was in part a result of more favorable donor-recipient matching. (Hepatology 2018;67:273-281).

Successful introduction of Model for End-stage Liver Disease scoring in deceased donor liver transplantation in Korea: analysis of first 1 year experience at a high-volume transplantation center

Backgrounds/Aims

Model for End-stage Liver Disease (MELD) score was adopted in June 2016 in Korea.

Methods

We analyzed changes in volumes and outcomes of deceased donor liver transplantation (DDLT) for 1 year before and after introduction of MELD scoring at Asan Medical Center.

Results

There were 64 cases of DDLT in 1 year before MELD introduction and 106 in 1 year after MELD introduction, an increase of 65%. The volume of DDLTs abruptly increased during first 3 months, but then returned to its usual level before MELD introduction, which indicated 3-month depletion of accumulated recipient pool with high MELD scores. The number of pediatric DDLT cases increased from 3 before MELD introduction to 11 after it, making up 21.4% and 47.8% of all cases of pediatric liver transplantation, respectively. The number of cases of retransplanted DDLTs increased from 4 to 27, representing 6.3% and 25.5% of all DDLT cases, respectively. The number of status 1 DDLT cases increased from 5 to 12, being 7.8% and 11.3% of all cases. Patient survival outcomes were similar before and after MELD introduction.

Conclusions

The number of DDLTs temporarily increased after adoption of MELD scoring due to accumulated recipient pool with high MELD scores. The numbers of retransplanted and pediatric DDLT cases significantly increased. Patient survival in adult and pediatric DDLT was comparable before and after adoption of MELD scoring. These results imply that Korean MELD score-based allocation system was successfully established within its first year.

Outcomes and disparities in liver transplantation will be improved by redistricting-cons

PURPOSE OF REVIEW

Over the last 2 years, the liver transplant community has been debating a proposal to redraw the maps of organ distribution. The basis for these proposed changes is reported disparities in severity of illness at transplantation across the USA - however, this is based on the allocation model for end-stage liver disease score. In this review, we provide a critical overview of the redistribution proposal, its flaws and how it may worsen outcomes and exacerbate disparities in liver transplantation.

RECENT FINDINGS

The main findings we highlight are data questioning the disparity metric used to justify the redistribution. We also review data published in recent articles and presented at public forums questioning whether there truly are disparities in access to transplant care among the broader population with liver disease, and whether disparities even getting to the waitlist are important and not to be ignored.

SUMMARY

This review article highlights major methodological and policy flaws with the current redistribution proposal. We demonstrate how the waitlist disparities that the proposal is intended to fix are not as they seem. Furthermore, if this proposal is passed, outcomes of liver transplantation nationally may worsen, and disparities for those with limited access to healthcare will worsen.

The donor risk index: A decade of experience

In 2006, derivation of the donor risk index (DRI) highlighted the importance of donor factors for successful liver transplantation. Over the last decade, the DRI has served as a useful metric of donor quality and has enhanced our understanding of donor factors and their impact upon recipients with hepatitis C virus, those with low Model for End-Stage Liver Disease (MELD) score, and individuals undergoing retransplantation. DRI has provided the transplant community with a common language for describing donor organ characteristics and has served as the foundation for several tools for organ risk assessment. It is a useful tool in assessing the interactions of donor factors with recipient factors and their impact on posttransplant outcomes. However, limitations of statistical modeling, choice of donor factors, exclusion of unaccounted donor and geographic factors, and the changing face of the liver transplant recipient have tempered its widespread use. In addition, the DRI was derived from data before the MELD era but is currently being applied to expand the donor pool while concurrently meeting the demands of a dynamic allocation system. A decade after its introduction, DRI remains relevant but may benefit from being updated to provide guidance in the use of extended criteria donors by accounting for the impact of geography and unmeasured donor characteristics. DRI could be better adapted for recipients with nonalcoholic fatty liver disease by examining and including recipient factors unique to this population. Liver Transplantation 23 1216-1225 2017 AASLD.

Same policy, different impact: Center-level effects of share 35 liver allocation

Early studies of national data suggest that the Share 35 allocation policy increased liver transplants without compromising posttransplant outcomes. Changes in center-specific volumes and practice patterns in response to the national policy change are not well characterized. Understanding center-level responses to Share 35 is crucial for optimizing the policy and constructing effective future policy revisions. Data from the United Network for Organ Sharing were analyzed to compare center-level volumes of allocation-Model for End-Stage Liver Disease (aMELD) ≥ 35 transplants before and after policy implementation. There was significant center-level variation in the number and proportion of aMELD ≥ 35 transplants performed from the pre- to post-Share 35 period; 8 centers accounted for 33.7% of the total national increase in aMELD ≥ 35 transplants performed in the 2.5-year post-Share 35 period, whereas 25 centers accounted for 65.0% of the national increase. This trend correlated with increased listing at these centers of patients with Model for End-Stage Liver Disease (MELD) ≥ 35 at the time of initial listing. These centers did not overrepresent the total national volume of liver transplants. Comparison of post-Share 35 aMELD to calculated time-of-transplant (TOT) laboratory MELD scores showed that only 69.6% of patients transplanted with aMELD ≥ 35 maintained a calculated laboratory MELD ≥ 35 at the TOT. In conclusion, Share 35 increased transplantation of aMELD ≥ 35 recipients on a national level, but the policy asymmetrically impacted practice patterns and volumes of a subset of centers. Longer-term data are necessary to assess outcomes at centers with markedly increased volumes of high-MELD transplants after Share 35. Liver Transplantation 23 741-750 2017 AASLD.

Share 35 changes in center-level liver acceptance practices

Share 35 was implemented to provide improved access to organs for patients with Model for End-Stage Liver Disease (MELD) scores ≥ 35. However, little is known about the impact of Share 35 on organ offer acceptance rates. We evaluated all liver offers to adult patients who were ultimately transplanted between January 1, 2011 and December 31, 2015. The analyses focused on patients ranked in the top 5 positions of a given match run and used multilevel mixed-effects models, clustering on individual wait-list candidate and transplant center. There was a significant interaction between Share 35 era and MELD category (P < 0.001). Comparing offers to MELD score ≥ 35 patients, offers after Share 35 were 36% less likely to be accepted compared with offers to MELD score ≥ 35 patients before Share 35 (adjusted odds ratio, 0.64). There was no clinically meaningful difference in the donor risk index of livers that were declined for patients with an allocation MELD score ≥35 in the pre- versus post-Share 35 era. Organ offer acceptance rates for patients with an allocation MELD ≥ 35 decreased in every region after Share 35; the magnitude of these changes was bigger in regions 2, 3, 4, 5, 6, 7, and 11, compared with regions 8 and 9 that had regional sharing in place before Share 35. There were significant changes in organ offer acceptance rates at the center level before versus after Share 35, and these changes varied across centers (P < 0.001). In conclusion, in liver transplantation candidates achieving a MELD score ≥ 35, liver acceptance of offers declined significantly after implementation of Share 35. The alterations in behavior at the center level suggest that practice patterns changed as a direct result of Share 35. Changes in organ acceptance under even broader organ sharing (redistricting) would likely be even greater, posing major logistical and operational challenges, while potentially increasing discard rates, thus decreasing the total number of transplants nationally. Liver Transplantation 23 604-613 2017 AASLD.

Waitlist Outcomes of Liver Transplant Candidates Who Were Reprioritized Under Share 35

Under Share 35, deceased donor (DD) livers are offered regionally to candidates with Model for End-Stage Liver Disease (MELD) scores ≥35 before being offered locally to candidates with MELD scores <35. Using Scientific Registry of Transplant Recipients data from June 2013 to June 2015, we identified 1768 DD livers exported to regional candidates with MELD scores ≥35 who were transplanted at a median MELD score of 39 (interquartile range [IQR] 37-40) with 30-day posttransplant survival of 96%. In total, 1764 (99.8%) exports had an ABO-compatible candidate in the recovering organ procurement organization (OPO), representing 1219 unique reprioritized candidates who would have had priority over the regional candidate under pre-Share 35 allocation. Reprioritized candidates had a median waitlist MELD score of 31 (IQR 27-34) when the liver was exported. Overall, 291 (24%) reprioritized candidates had a comparable MELD score (within 3 points of the regional recipient), and 209 (72%) were eventually transplanted in 11 days (IQR 3-38 days) using a local (50%), regional (50%) or national (<1%) liver; 60 (21%) died, 13 (4.5%) remained on the waitlist and nine (3.1%) were removed for other reasons. Of those eventually transplanted, MELD score did not increase in 57%; it increased by 1-3 points in 37% and by ≥4 points in 5.7% after the export. In three cases, OPOs exchanged regional exports within a 24-h window. The majority of comparable reprioritized candidates were not disadvantaged; however, 21% died after an export.

Liver transplantation after share 35: Impact on pretransplant and posttransplant costs and mortality

Share 35 was implemented in 2013 to direct livers to the most urgent candidates by prioritizing Model for End-Stage Liver Disease (MELD) ≥ 35 patients. We aim to evaluate this policy's impact on costs and mortality. Our study includes 834 wait-listed patients and 338 patients who received deceased donor, solitary liver transplants at Mayo Clinic between January 2010 and December 2014. Of these patients, 101 (30%) underwent transplantation after Share 35. After Share 35, 29 (28.7%) MELD ≥ 35 patients received transplants, as opposed to 46 (19.4%) in the pre-Share 35 era (P = 0.06). No significant difference in 90-day wait-list mortality (P = 0.29) nor 365-day posttransplant mortality (P = 0.68) was found between patients transplanted before or after Share 35. Mean costs were $3,049 (P = 0.30), $5226 (P = 0.18), and $10,826 (P = 0.03) lower post-Share 35 for the 30-, 90-, and 365-day pretransplant periods, and mean costs were $5010 (P = 0.41) and $5859 (P = 0.57) higher, and $9145 (P = 0.54) lower post-Share 35 for the 30-, 90-, and 365-day posttransplant periods. In conclusion, the added cost of transplanting more MELD ≥ 35 patients may be offset by pretransplant care cost reduction. Despite shifting organs to critically ill patients, Share 35 has not impacted mortality significantly. Liver Transplantation 23:11-18 2017 AASLD.