Exception Points Research Articles

Median Meld at Transplant Minus 3 Reduces the Mortality of Non-Hepatocellular Carcinoma Patients on the Liver Transplant Waitlist

Liver transplants (LTs) are prioritized by mortality risk, which is estimated by MELD scores. Since hepatocellular carcinoma (HCC) patients present with lower MELD scores, they are allocated MELD exception points. Concerns persist that HCC recipients are over-prioritized, resulting in disproportionate waitlist mortality among non-HCC patients. We assessed whether the Median Meld at Transplant minus 3 (MMaT-3) scoring system would balance waitlist mortality and transplantation rates between HCC and non-HCC patients. We reviewed 266 patient charts listed for an LT from 2015 to 2023; 46.2% were listed in the MMaT-3 era. Amongst non-HCC patients, MMaT-3 implementation significantly increased 1-year transplant rate and reduced 1-year waitlist mortality among non-HCC patients (p = 0.003). Pre-MMaT-3 gaps in transplantation (p = 0.004) and waitlist dropout (p = 0.01) were eliminated post-implementation (p > 0.05). Amongst HCC patients, MMaT-3 implementation had no impact on the 1-year transplant rate (p = 0.92) or 1-year waitlist mortality (p = 0.66). Fine-gray proportional hazard multivariable analysis revealed that MMaT-3 significantly reduced waitlist mortality among non-HCC patients (asHR: 0.44, 95% CI [0.23, 0.83], p = 0.01) and limited impact on HCC patients (p = 0.31). MMaT-3 allocation did not significantly alter 2-year post-transplant survival for both populations. We show that the MMaT-3 system decreased the waitlist mortality of non-HCC patients with limited impacts on outcomes for HCC patients listed for an LT.

PRO: Patients with acute-on-chronic liver failure should receive MELD exception points.

PRO: Patients with acute-on-chronic liver failure should receive MELD exception points.

Continuous Risk Score Predicts Waitlist and Post-transplant Outcomes in Hepatocellular Carcinoma Despite Exception Changes

Background and AimsContinuous risk stratification of candidates and urgency-based prioritization have been utilized for liver transplantation (LT) in non-hepatocellular carcinoma (HCC) patients in the United States. Instead, for HCC patients, a dichotomous criterion with exception points is still used. This study evaluated the utility of the hazard associated with LT for HCC (HALT-HCC), an oncological continuous risk score, to stratify waitlist dropout and post-LT outcomes. MethodsA competing risk model was developed and validated using the UNOS database (2012-2021) through multiple policy changes. The primary outcome was to assess the discrimination ability of waitlist dropouts and LT outcomes. The study focused on the HALT-HCC score, compared to other HCC risk scores. ResultsAmong 23,858 candidates, 14,646 (59.9%) underwent LT and 5,196 (21.8%) dropped out of the waitlist. Higher HALT-HCC scores correlated with increased dropout incidence and lower predicted five-year overall survival after LT. HALT-HCC demonstrated the highest AUC values for predicting dropout at various intervals post-listing (0.68 at six months, 0.66 at one year), with excellent calibration (R2=0.95 at six months, 0.88 at one year). Its accuracy remained stable across policy periods and locoregional therapy applications. ConclusionsThis study highlights the predictive capability of the continuous oncological risk score to forecast waitlist dropout and post-LT outcomes in HCC patients, independent of policy changes. The study advocates integrating continuous scoring systems like HALT-HCC in liver allocation decisions, balancing urgency, organ utility, and survival benefit.

Dynamic Exception Points for Fair Liver Allocation

There are disparities in access to livers based on transplant patients’ height, which disproportionately affects Hispanics, Asians, and women (across all ethnicities), because short patients can receive transplants from a smaller pool of available deceased donors for medical reasons. Reduced likelihood of transplantation leads to higher mortality rates and longer waiting times. We analyze fairness within the current U.S. liver allocation system where patients receive priority dynamically, based on their model for end-stage liver disease (MELD) scores, which reflect the severity of liver disease. We propose a simple adjustment, providing additional (exception) points based on height and MELD score, that can be easily implemented in practice, which materially reduces the disparity without sacrificing overall efficiency. We model the liver allocation system as a multiclass fluid model of overloaded queues with heterogeneous servers. We impose explicit equity constraints for all static patient classes, that is, height. We characterize the optimal solution under the objective of minimizing pretransplant mortality. The discretized version of the optimal policy is numerically solved using estimates from clinical data and a detailed simulation study demonstrates its effectiveness. The optimal policy, called the equity adjusted mortality risk policy, advocates ranking patients based on their short-term mortality risk adjusted for equity among height classes. Interpretation of the shadow prices of equity constraints in the optimal control problem as MELD exception points is novel in the transplant context since they can be seamlessly mapped into the existing system. Our simulations show that for women, the disparity can be almost completely eliminated. Hispanics and Asians greatly benefit from receiving these MELD exception points also. Our work provides a remedy to reduce the disparities in access to liver transplantation within the MELD-based allocation. Our approach can help the on-going analysis of the continuous distribution model for livers because it also considers aspects of candidate biology, notably height and body surface area. Funding: M. Akan was supported by the National Science Foundation [Grant CMMI-1334194] and the Carnegie Mellon University (CMU) [Onetto Fellowship in Operations Management]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/serv.2023.0092 .

The impact of MELD exception points for hydrothorax on posttransplant mortality: a propensity score-matched analysis.

Hepatic hydrothorax is a challenging complication of end-stage liver disease, and.patients with this complication can receive model for end-stage liver disease (MELD) exception points if they meet specific criteria as defined by United Network for Organ Sharing (UNOS). This research aimed to analyze the effect of receiving MELD exception points for hepatic hydrothorax on posttransplant mortality, using a national transplant database. Patients >18 years in the UNOS database awaiting liver transplant between 2012 and 2023 were identified based on their petition for MELD exception points. Using a 1: 1 propensity score-matched analysis, 302 patients who received MELD exception points for hepatic hydrothorax were compared with 302 patients who did not receive MELD exception points.Demographic, clinical and laboratory values were compared. The primary outcome was posttransplant mortality. Multivariate logistic regression controlled for potential confounders. No significant difference was observed in mean age (58.20 vs 57.62 years), mean initial MELD score (16.93 vs 16.54), or mean Child-Pugh score (9.77 vs 9.74) in patients with hepatic hydrothorax receiving MELD exception points versus their matched cohort who did not recieve exception points. The proportion of males was slightly higher among patients who received MELD exception points (57.6% males vs 53.6% males). A majority of patients in both groups had Child-Pugh grade C (>56%). Patients receiving MELD exception points for hepatic hydrothorax had a statistically significant 44% decrease in the odds of posttransplant death compared to those who did not (OR 0.56; 95% CI 0.37-0.88; P = 0.01). Among the combined cohort, each year increase in age resulted in a 3.9% increase in mortality (OR 1.04; 95% CI 1.01-1.07; P = 0.005), and every one-unit increase in serum creatinine resulted in a 40% increase in mortality (OR 1.40; 95% CI 1.03-1.92; P = 0.03). Receiving MELD exception points for hepatic hydrothorax is associated with a significant reduction in the odds of posttransplant mortality. These findings underscore the importance of MELD exception points for hepatic hydrothorax among patients with decompensated cirrhosis, potentially improving patient prioritization for liver transplantation and influencing clinical decision-making.

Racial-ethnic differences in liver transplant waitlist outcomes in patients with hepatocellular carcinoma before and after recent changes to allocation policy.

In May 2019, liver transplant (LT) allocation policy changed to limit MELD exception points for hepatocellular carcinoma (HCC) to median MELD at transplant minus three (MMaT-3). We evaluated this policy's impact on waitlist outcomes for HCC candidates, by race and ethnicity, hypothesizing that the introduction of the MMaT-3 reduced inequities in waitlist outcomes. Retrospective cohort study of the Scientific Registry for Transplant Recipients, including all adult LT candidates (N=10751) who received HCC exception points from May 17, 2017 to May 18, 2019 (pre-policy; N=6627) to May 19, 2019 to March 1, 2021 (post-policy; N=4124). We compared incidence of LT and waitlist removal for death or becoming too sick pre- and post-policy for non-Hispanic White, non-Hispanic Black, Hispanic/Latinx, and Asian patients using competing risk regression adjusted for candidate characteristics. One-year cumulative incidence of LT decreased significantly pre-/post-policy among White (77.4%vs. 64.5%; p<.01) and Black (76.2%vs. 63.1%; p<.01) candidates only, while a 1-year incidence of death/non-LT waitlist removal decreased significantly only among Hispanics (13.4%vs. 7.5%; p<.01). After covariate adjustment, the effect of the policy change was a significantly decreased incidence of LT for White (SHR:.63 compared to pre-policy; p<.001), Black (SHR:.62; p<.001), and Asian (SHR:.68; p=.002), but no change for Hispanic patients. Only Hispanic patients had a significant decrease in death/waitlist removal after the policy change (SHR: .69; p=.04). Compared to White patients in the pre-policy era, Hispanic (SHR: .88, p<.007) and Asian candidates (SHR: .72; p<.001) had lower unadjusted incidence of LT. This disparity was mitigated in the post-policy era where Hispanic patients had higher likelihood of LT than Whites (SHR: 1.22; p=.002). For the outcome of death/non-LT waitlist removal, the only significant difference was a 42% lower incidence of waitlist removal for Asian compared to White patients in the post-policy era (SHR: .58; p=.03). Among LT recipients with HCC, racial/ethnic subpopulations were differentially affected by the MMAT-3 policy, resulting in a post-policy reduction of some of the previous disparities.

From Patients to Providers: Assessing Impact of Normothermic Machine Perfusion on Liver Transplant Practices in the US.

Normothermic machine perfusion (NMP) of livers allows for the expansion of the donor pool and minimization of posttransplant complications. Results to date have focused on both donor and recipient outcomes, but there remains potential for NMP to also impact transplant providers. Using United Network for Organ Sharing Standard Transplant Analysis file data, adult deceased donors who underwent transplantation between January 1, 2016, and December 31, 2022, were identified. Transplanted livers were divided by preservation methods (static cold storage [SCS] and NMP) and case time (day-reperfusion 8 am to 6 pm ). Patient factors, transplant characteristics, and short-term outcomes were analyzed between Mahalanobis-metric-matched groups. NMP livers represented 742 (1.4%) of 52,132 transplants. NMP donors were more marginal with higher Donor Risk Index scores (1.78 ± 0.50 NMP vs 1.49 ± 0.38 SCS, p < 0.001) and donation after cardiac death frequency (36.9% vs 8.4%, p < 0.001). NMP recipients more often had model for end-stage liver disease (MELD) exception status (29.9% vs 23.4%, p < 0.001), lower laboratory MELD scores (20.7 ± 9.7 vs 24.3 ± 10.9, p < 0.001), and had been waitlisted longer (111.5 [21.0 to 307.0] vs 60.0 [9.0 to 245.0] days, p < 0.001). One-year graft survival (90.2% vs 91.6%, p = 0.505) was similar between groups, whereas length of stay was lower for NMP recipients (8.0 [6.0 to 14.0] vs 10.0 [6.0 to 16.0], p = 0.017) after adjusting for confounders. Notably, peak case volume occurred at 11 am with NMP livers (vs 9 pm with SCS). Overall, a higher proportion of transplants was performed during daytime hours with NMP (51.5% vs 43.0%, p < 0.001). NMP results in increased use of marginal allografts, which facilitated transplantation in lower laboratory MELD recipients who have been waitlisted longer and often have exception points. Importantly, NMP also appeared to shift peak caseloads from nighttime to daytime, which may have significant effects on the quality of life for the entire liver transplant team.

Waitlist Outcomes for Exception and Non-exception Liver Transplant Candidates in the United States Following Implementation of the Median MELD at Transplant (MMaT)/250-mile Policy.

Since February 2020, exception points have been allocated equivalent to the median model for end-stage liver disease at transplant within 250 nautical miles of the transplant center (MMaT/250). We compared transplant rate and waitlist mortality for hepatocellular carcinoma (HCC) exception, non-HCC exception, and non-exception candidates to determine whether MMaT/250 advantages (or disadvantages) exception candidates. Using Scientific Registry of Transplant Recipients data, we identified 23 686 adult, first-time, active, deceased donor liver transplant (DDLT) candidates between February 4, 2020, and February 3, 2022. We compared DDLT rates using Cox regression, and waitlist mortality/dropout using competing risks regression in non-exception versus HCC versus non-HCC candidates. Within 24 mo of study entry, 58.4% of non-exception candidates received DDLT, compared with 57.8% for HCC candidates and 70.5% for non-HCC candidates. After adjustment, HCC candidates had 27% lower DDLT rate (adjusted hazard ratio = 0.68 0.73 0.77 ) compared with non-exception candidates. However, waitlist mortality for HCC was comparable to non-exception candidates (adjusted subhazard ratio [asHR] = 0.93 1.03 1.15 ). Non-HCC candidates with pulmonary complications of cirrhosis or cholangiocarcinoma had substantially higher risk of waitlist mortality compared with non-exception candidates (asHR = 1.27 1.70 2.29 for pulmonary complications of cirrhosis, 1.35 2.04 3.07 for cholangiocarcinoma). The same was not true of non-HCC candidates with exceptions for other reasons (asHR = 0.54 0.88 1.44 ). Under MMaT/250, HCC, and non-exception candidates have comparable risks of dying before receiving liver transplant, despite lower transplant rates for HCC. However, non-HCC candidates with pulmonary complications of cirrhosis or cholangiocarcinoma have substantially higher risk of dying before receiving liver transplant; these candidates may merit increased allocation priority.

Expanding MELD exceptions for colorectal liver metastasis: data and policy.

While liver transplant for unresectable colorectal cancer liver metastases (CRLM) has been demonstrated to be a promising treatment in selected patients, the typically low MELD score of these patients and lack of exception points may lead to challenges in receiving a deceased donor liver for transplant. Several studies have shown improved outcomes in select patients with CRLM who undergo liver transplant, and several trials are ongoing and will conclude in the next several years. MELD exception points have recently been proposed in qualifying patients with CRLM to help this group obtain more timely quality allografts. Under the current proposal, patients with CRLM would receive a score of the median MELD at transplant (MMaT) for their center minus 20 with a minimum score of 15 in cases where MMaT minus 20 would be less than 15. This would allow them to receive transplants faster without competing unnecessarily with those with greater medical need. Giving MELD exception points to patients with colorectal cancer liver metastases in need of transplant may decrease time on the waitlist and improve outcomes for these patients.

Excess waitlist mortality among candidates for multivisceral liver-intestine transplant in acuity circle allocation

Candidates for multivisceral transplant (MVT) have experienced decreased access to transplant in recent years. Using Organ Procurement and Transplantation Network data, transplant and waiting list outcomes for MVT (ie, liver-intestine, liver-intestine-pancreas, and liver-intestine-kidney-pancreas) candidates listed between February 4, 2018, and February 3, 2022, were analyzed, including model for end-stage liver disease/pediatric end-stage liver disease and exception scores by era (before and after acuity circle [AC] implementation on February 4, 2020) and age group (pediatric and adult). Of 284 MVT waitlist registrations (45.6% pediatric), fewer had exception points at listing post-AC compared to pre-AC (10.0% vs 19.1%), and they were less likely to receive transplant (19.1% vs 35.9% at 90 days; 35.7% vs 57.2% at 1 year). Of 177 MVT recipients, exception points at transplant were more common post-AC compared to pre-AC (30.8% vs 20.2%). Postpolicy, adult MVT candidates were more likely to be removed due to death/too sick compared with liver-alone candidates (13.5% vs 5.6% at 90 days; 24.2% vs 9.8% at 1 year), whereas no excess waitlist mortality was observed among pediatric MVT candidates. Under current allocation policy, multivisceral candidates experience inferior waitlist outcomes compared with liver-alone candidates. Clarification of guidance around submission and approval of multivisceral exception requests may help improve their access to transplantation and achieve equity between multivisceral and liver-alone candidates on the liver transplant waiting list.

The role of exception points in outcomes of patients with fibrocystic liver-kidney disease: Implications for the National Liver Review Board.

The role of exception points in outcomes of patients with fibrocystic liver-kidney disease: Implications for the National Liver Review Board.

Impact of Median MELD at Transplant Minus 3 National Policy on Quality of Transplanted Livers for Patients With and Without Hepatocellular Carcinoma.

Patients with hepatocellular carcinoma (HCC) have been overprioritized in the deceased donor liver allocation system. The United Network for Organ Sharing adopted a policy in May 2019 that limited HCC exception points to the median Model for End-Stage Liver Disease at transplant in the listing region minus 3. We hypothesized this policy change would increase the likelihood to transplant marginal quality livers into HCC patients. This was a retrospective cohort study of a national transplant registry, including adult deceased donor liver transplant recipients with and without HCC from May 18, 2017, to May 18, 2019 (prepolicy) to May 19, 2019, to March 1, 2021 (postpolicy). Transplanted livers were considered of marginal quality if they met ≥1 of the following: (1) donation after circulatory death, (2) donor age ≥70, (3) macrosteatosis ≥30% and (4) donor risk index ≥95th percentile. We compared characteristics across policy periods and by HCC status. A total of 23 164 patients were included (11 339 prepolicy and 11 825 postpolicy), 22.7% of whom received HCC exception points (prepolicy versus postpolicy: 26.1% versus 19.4%; P = 0.03). The percentage of transplanted donor livers meeting marginal quality criteria decreased for non-HCC (17.3% versus 16.0%; P < 0.001) but increased for HCC (17.7% versus 19.4%; P < 0.001) prepolicy versus postpolicy. After adjusting for recipient characteristics, HCC recipients had 28% higher odds of being transplanted with marginal quality liver independent of policy period (odds ratio: 1.28; confidence interval, 1.09-1.50; P < 0.01). The median Model for End-Stage Liver Disease at transplant in the listing region minus 3 policy limited exception points and decreased the quality of livers received by HCC patients.

Trajectories of patients relisted for liver transplantation

Introduction and ObjectivesRecurrent cirrhosis complicates 10-30% of Liver transplants (LT) and can lead to consideration for re-transplantation. We evaluated the trajectories of relisted versus primary listed patients on the waitlist using a competing risk framework. Materials and MethodsWe retrospectively examined 1,912 patients listed for LT at our centre between from 2012 to 2020. Cox proportional hazard models were used to assess overall survival (OS) by listing type and competing risk analysis Fine-Gray models were used to assess cumulative incidence of transplant by listing type. Results1,731 patients were included (104 relisted). 44.2% of relisted patients received exception points vs. 19.8% of primary listed patients (p<0.001). Patients relisted without exceptions, representing those with graft cirrhosis, had the worst OS (HR: 4.17, 95%CI 2.63 – 6.67, p=<0.0001) and lowest instantaneous rate of transplant (HR: 0.56, 95%CI 0.38 – 0.83, p=0.006) than primary listed with exception points. On multivariate analysis listing type, height, bilirubin and INR were associated with cumulative incidence of transplant, while listing type, bilirubin, INR, sodium, creatinine were associated with OS. Within relisted patients, there was a trend towards higher mortality (HR: 1.79, 95%CI 0.91 – 3.52, p=0.08) and low transplant incidence (HR: 0.51, 95%CI 0.22 – 1.15, p=0.07) for graft cirrhosis vs other relisting indications. ConclusionsPatients relisted for LT are carefully curated and comprise a minority of the waitlist population. Despite their younger age, they have worse liver/kidney function, poor waitlist survival, and decreased transplant incidence suggesting the need for early relisting, while considering standardized exception points.

The number of hepatocellular carcinoma foci as predictor of poor response to tumor-directed therapies in patients awaiting liver transplantation: a prospective cohort study.

Tumor-directed therapies (TDTs) are a constitutive part of hepatocellular carcinoma (HCC) treatment in patients awaiting liver transplantation (LT). While most patients benefit from TDTs as a bridge to LT, some patients drop out from the waiting list due to tumor progression. The study aimed to determine the risk factors for poor treatment outcome following TDTs among patients with HCC awaiting LT. A total of 123 patients with HCC were evaluated with 92 patients meeting Milan Criteria enrolled in the prospective cohort study. Tumor response was evaluated using the modified Response Evaluation Criteria for Solid Tumors for HCC 1 month after the procedure. The risk factors for progressive disease (PD) and dropout were evaluated. After TDT, 55 patients (59.8%) achieved complete or partial response (44.6% and 15.2% respectively), 17 patients (18.5%) had stable disease, and 20 patients (21.7%) were assessed as PD. Multivariate analysis revealed a significant and independent association between the number of HCC foci and PD ( P = 0.03, OR = 2.68). There was no statistically significant association between treatment response and demographics, MELDNa score, pre-and post-treatment alpha-fetoprotein (AFP), cumulative tumor burden the largest tumor size, or TDT modality. PD was the major cause of dropout in our cohort. Pre-treatment AFP levels ≥200 ng/ml had a strong association with dropout after TDTs ( P = 0.0005). This study demonstrated the presence of multifocal HCC is the sole prognostic factor for PD following TDTs in HCC patients awaiting LT. We recommend prioritizing patients with multifocal HCC within Milan criteria by exception points for LT to improve the dropout rate.

Living donor liver transplantation can address disparities in transplant access for patients with primary sclerosing cholangitis.

Liver transplantation (LT) is frequently lifesaving for people living with primary sclerosing cholangitis (PSC). However, patients are waitlisted for LT according to the model for end-stage liver disease-sodium (MELD-Na) score, which may not accurately reflect the burden of living with PSC. We sought to describe and analyze the clinical trajectory for patients with PSC referred for LT, in a mixed deceased donor/living donor transplant program. This was a retrospective cohort study from November 2012 to December 2019, including all patients with PSC referred for assessment at the University Health Network Liver Transplant Clinic. Patients who required multiorgan transplant or retransplantation were excluded. Liver symptoms, hepatobiliary malignancy, MELD-Na progression, and death were abstracted from chart review. Competing risk analysis was used for timing of LT, transplant type, and death. Of 172 PSC patients assessed, 84% (n = 144) were listed of whom 74% were transplanted. Mean age was 47.6 years, and 66% were male. Overall mortality was 18.2% at 2 years. During the follow-up, 16% (n = 23) were removed from the waitlist for infection, clinical deterioration, liver-related mortality or new cancer; 3 had clinical improvement. At listing, 82% (n = 118) had a potential living donor (pLD). Patients with pLD had significantly lower waitlist and liver-related waitlist mortality (HR 0.20, p<0.001 and HR 0.17, p<0.001, respectively), and higher rates of transplantation (HR 1.83, p = 0.05). Exception points were granted to 13/172 (7.5%) patients. In a high-volume North American LT center, most patients with PSC assessed for transplant were listed and subsequently transplanted. However, this was a consequence of patients engaging in living donor transplantation. Our findings support the concern from patients with PSC that MELD-Na allocation does not adequately address their needs.

Impact of the COVID-19 pandemic on liver transplant waitlist outcome in France

The objective of this study was to investigate the impact of the COVID-19 pandemic on the outcome of patients on the liver transplantation (LT) waitlist in 2020 in France, in particular, the incidence of deaths and delisting for worsening condition, depending on the allocation score component. The 2020 cohort of patients on the waiting list was compared with the 2018/2019 cohorts. 2020 saw fewer LTs than in either 2019 or 2018 (1128, 1356, and 1325, respectively), together with fewer actual brain dead donors (1355, 1729, and 1743). In 2020, deaths or delisting for worsening condition increased significantly versus 2018/2019 (subdistribution hazard ratio 1.4, 95% confidence interval [CI] 1.2–1.7), after adjustment for age, place of care, diabetes, blood type, and score component, although COVID-19-related mortality was low. This increased risk mainly concerned patients with hepatocellular carcinoma (1.52, 95% CI 1.22–1.90), with 650 MELD exception points (2.19, 95% CI 1.08–4.43), and especially those without HCC and MELD scores from 25 to 30 (3.36 [95% CI 1.82–6.18]). In conclusion, by significantly decreasing LT activity in 2020, the COVID-19 pandemic increased the number of waitlist deaths and delisting for worsening condition, and significantly more for particular components of the score, including intermediate severity cirrhosis.

Reassessing the survival benefit of deceased donor liver transplantation: retrospective cohort study.

Currently in the United States, deceased donor liver transplant (DDLT) allocation priority is based on the model for end-stage liver disease including sodium (MELD-Na) score. The United Network for organ sharing's 'Share-15' policy states that candidates with MELD-Na scores of 15 or greater have priority to receive local organ offers compared to candidates with lower MELD-Na scores. Since the inception of this policy, major changes in the primary etiologies of end-stage liver disease have occurred and previous assumptions need to be recalibrated. The authors retrospectively analyzed the Scientific Registry of Transplant Recipients database between 2012 and 2021 to determine life years saved by DDLT at each interval of MELD-Na score and the time-to-equal risk and time-to-equal survival versus remaining on the waitlist. The authors stratified our analysis by MELD exception points, primary disease etiology, and MELD score. On aggregate, compared to remaining on the waitlist, a significant 1-year survival advantage of DDLT at MELD-Na scores as low as 12 was found. The median life years saved at this score after a liver transplant was estimated to be greater than 9 years. While the total life years saved were comparable across all MELD-Na scores, the time-to-equal risk and time-to-equal survival decreased exponentially as MELD-Na scores increased. Herein, the authors challenge the perception as to the timing of DDLT and when that benefit occurs. The national liver allocation policy is transitioning to a continuous distribution framework and these data will be instrumental to defining the attributes of the continuos allocation score.

A42 LIVE DONOR LIVER TRANSPLANTATION IN PRIMARY SCLEROSING CHOLANGITIS: AN INDICATOR OF AN ORGAN ALLOCATION SYSTEM NOT ADDRESSING PATIENT NEED

Abstract Background Liver transplantation is frequently lifesaving for people living with primary sclerosing cholangitis (PSC). However, patients are waitlisted for liver transplant (LT) according to the MELD-Na score, which may not accurately reflect the burden of living with PSC. Purpose We sought to describe and analyze the clinical trajectory for patients with PSC referred for LT, in a mixed deceased donor/live donor transplant programme. Method This was a retrospective cohort study from November 2012 to December 2019 including all patients with PSC referred for assessment at the University Health Network Liver Transplant Clinic. Patients who required multiorgan transplant or re-transplantation were excluded. Liver symptoms, hepatobiliary malignancy, MELD-Na progression, and death were abstracted from chart review. Competing Risk analysis was used for timing of LT, transplant type, and death. Result(s) Of 172 PSC patients assessed, 144 (84%) were listed, of whom 106/144 (74%) were transplanted. Mean age was 47.6 years and 66% were male. During follow-up through to 2021, 23/144 (16%) were removed from the waitlist due to infection, clinical deterioration, liver-related mortality or new cancer; 3 had clinical improvement. At the time of listing, 118/144 (81.95%) had a potential Living Donor (pLD) of whom 94 were transplanted: 64 live donor and 30 deceased donor. Patients with pLD had 79% lower mortality (p&amp;lt;0.001), and higher rates of transplantation (80% vs 46%). Exception points were granted to 13/172 (7.5%) patients. Conclusion(s) In a high-volume North American liver transplant centre, most patients with PSC assessed for transplant were listed and subsequently transplanted. However, this was a consequence of patients engaging in live donor transplantation. Our findings support the concern from patients with PSC that MELD-Na allocation does not adequately address their needs. Please acknowledge all funding agencies by checking the applicable boxes below CIHR, Other Please indicate your source of funding; This study was supported by PSC Partners Canada, Canadian Institutes of Health Research (CIHR), Toronto General and Western Hospital Foundation. Disclosure of Interest None Declared

Quantum phase transitions in non-Hermitian [formula omitted]-symmetric transverse-field Ising spin chains

We present a theoretical study of quantum phases and quantum phase transitions occurring in non-Hermitian PT-symmetric superconducting qubits chains described by a transverse-field Ising spin model. A non-Hermitian part of the Hamiltonian is implemented via imaginary staggered longitudinal magnetic field, which corresponds to a local staggered gain and loss terms. By making use of a direct numerical diagonalization of the Hamiltonian for spin chains of a finite size N, we explore the dependencies of the energy spectrum, including the energy difference between the first excited and the ground states, the spatial correlation function of local polarization (z-component of local magnetization) on the adjacent spins interaction strength J and the local gain (loss) parameter γ. A scaling procedure for the correlation length ξ allows us to establish a complete quantum phase diagram of the system. We obtain two quantum phases for J<0, namely, PT-symmetry broken antiferromagnetic state and PT-symmetry preserved paramagnetic state, and the quantum phase transition line between them is the line of exception points. For J>0 the PT-symmetry of the ground state is retained in a whole region of parameter space of J and γ, and a system shows two intriguing quantum phase transitions between ferromagnetic and paramagnetic states for a fixed parameter γ>1. We also provide the qualitative quantum phase diagram γ−J derived in the framework of the Bethe–Peierls approximation that is in a good accord with numerically obtained results.

PRO: Is liver organ allocation with MMaT-3 appropriate prioritization for patients with liver cancer?

PRO: Is liver organ allocation with MMaT-3 appropriate prioritization for patients with liver cancer?