Implementation of a National Liver Review Board for exception requests in the United States: A 2-year monitoring report

The exception point system for liver allocation in the United States allows for additional waitlist priority for candidates where the Model for End-Stage Liver Disease or Pediatric End-stage Liver Disease does not effectively represent their urgency or need for a transplant. In May 2019, the review process for liver exception cases transitioned from 11 Regional Review Boards (RRBs) to 1 National Liver Review Board (NLRB), intended to increase consistency nationwide, improve efficiency, and balance transplant access for candidates with and without exception scores. This report provides a review of liver exception request and review practices, waitlist outcomes, and transplant activity in the first 2 years after implementation of the NLRB and acuity circle-based distribution in the United States. We compared initial and extension exception request forms submitted from May 13, 2017 to May 13, 2019 (prepolicy or RRB era) to the period from February 4, 2020 to February 3, 2022 (postpolicy or NLRB era). During this time, the NLRB reviewed 10,083 initial exception requests and 12,686 extension requests. Notable postpolicy highlights include (1) an increase in the proportion of initial and extension requests that were automatically approved instead of manually reviewed; (2) a decrease in the overall approval rates of initial exception requests (87.8% for adult HCC, 64.3% for adult other diagnoses, and 71.5% for pediatric); and (3) reduction in the time from exception request submission to adjudication to a median of 3.73 days. The proportions of waitlist registration and deceased donor liver transplants for patients with exception scores decreased, and waitlist outcomes between patients with and without exception scores are now comparable. Implementation of the NLRB improved efficiency, reduced case workloads, and standardized criteria for exception cases, with similar waitlist outcomes between patients with and without exception scores and improved equity in terms of access to liver transplants.

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.

Decreased Utilization Rate of Grafts for Liver Transplantation After Implementation of Acuity Circle-based Allocation

BACKGROUND

The allocation system for livers began using acuity circles (AC) in 2020. In this study, we sought to evaluate the impact of AC policy on the utilization rate for liver transplantation (LT).

METHODS

Using the US national registry data between 2018 and 2022, LTs were equally divided into 2 eras: pre-AC (before February 4, 2020) and post-AC (February 4, 2020, and after). Deceased potential liver donors were defined as deceased donors from whom at least 1 organ was procured.

RESULTS

The annual number of deceased potential liver donors increased post-AC (from 10 423 to 12 259), approaching equal to that of new waitlist registrations for LT (n = 12 801). Although the discard risk index of liver grafts was comparable between the pre- and post-AC eras, liver utilization rates in donation after brain death (DBD) and donation after circulatory death (DCD) donors were lower post-AC ( P  < 0.01; 79.8% versus 83.4% and 23.7% versus 26.0%, respectively). Recipient factors, ie, no recipient located, recipient determined unsuitable, or time constraints, were more likely to be reasons for nonutilization after implementation of the AC allocation system compared to the pre-AC era (20.0% versus 12.3% for DBD donors and 50.1% versus 40.8% for DCD donors). Among non-high-volume centers, centers with lower utilization of marginal DBD donors or DCD donors were more likely to decrease LT volume post-AC.

CONCLUSIONS

Although the number of deceased potential liver donors has increased, overall liver utilization among deceased donors has decreased in the post-AC era. To maximize the donor pool for LT, future efforts should target specific reasons for liver nonutilization.

OPTN/SRTR 2022 Annual Data Report: Liver

In 2022, liver transplant activity continued to increase in the United States, with an all-time high of 9,527 transplants performed, representing a 52% increase over the past decade (2012-2022). Of these transplants, 8,924 (93.7%) were from deceased donors and 603 (6.3%) were from living donors. Liver transplant recipients were 94.5% adult and 5.5% pediatric. The overall size of the liver transplant waiting list contracted, with more patients being removed than added, although 10,548 adult patients still remained on the waiting list at the end of 2022. Alcohol-associated liver disease continued to be the leading diagnosis among both candidates and recipients, followed by metabolic dysfunction-associated steatohepatitis. Simultaneous liver-kidney transplant was the most common multiorgan combination, with 800 liver-kidney transplants performed in 2022; in addition, there were 303 new listings for kidney transplant via the safety net mechanism. Among adults added to the liver waiting list in 2021, 39.9% received a deceased donor liver transplant within 3 months; 45.7%, within 6 months; and 54.5%, within 1 year. Pretransplant mortality decreased to 12.3 deaths per 100 patient-years in 2022, although still 15.6% of removals from the waiting list were for death or being too sick for transplant. Graft and patient survival outcomes after deceased donor liver transplant improved, approximating pre-COVID-19 pandemic levels, with 5.1% mortality observed at 6 months; 6.8%, at 1 year; 12.7%, at 3 years; 19.8%, at 5 years; and 35.7%, at 10 years. Five-year graft and patient survival rates after living donor liver transplant exceeded those of deceased donor liver transplant. Candidates receiving model for end-stage liver disease exception points for hepatocellular carcinoma constituted 15.5% of transplants performed in 2022, with similar transplant rates and posttransplant outcomes compared to cases without hepatocellular carcinoma exception. In 2022, more pediatric liver transplant candidates were added to the waiting list and underwent transplant compared with either of the preceding 2 years, with an uptick in living donor liver transplant volume. Although pretransplant mortality has improved after the recent policy change prioritizing pediatric donors for pediatric recipients, still, in 2022, 50 children died or were removed from the waiting list for being too sick to undergo transplant. Posttransplant mortality among pediatric liver transplant recipients remained notable, with death occurring in 4.0% at 6 months, 6.0% at 1 year, 8.2% at 3 years, 9.8% at 5 years, and 13.9% at 10 years. Similar to adult living donor recipients, pediatric living donor recipients had better 5-year patient survival compared with deceased donor recipients.

Breaking distance barriers in liver transplantation: Risk factors and outcomes of long-distance liver grafts

BACKGROUND

Long-distance-traveling liver grafts in liver transplantation present challenges due to prolonged cold ischemic time and increased risk of ischemia-reperfusion injury. We identified long-distance-traveling liver graft donor and recipient characteristics and risk factors associated with long-distance-traveling liver graft use.

METHODS

We conducted a retrospective analysis of data from donor liver transplantation patients registered from 2014 to 2020 in the United Network for Organ Sharing registry database. Donor, recipient, and transplant factors of graft survival were compared between short-travel grafts and long-distance-traveling liver grafts (traveled >500 miles).

RESULTS

During the study period, 28,265 patients received a donation after brainstem death liver transplantation and 3,250 a donation after circulatory death liver transplantation. The long-distance-traveling liver graft rate was 6.2% in donation after brainstem death liver transplantation and 7.1% in donation after circulatory death liver transplantation. The 90-day graft survival rates were significantly worse for long-distance-traveling liver grafts (donation after brainstem death: 95.7% vs 94.5%, donation after circulatory death: 94.5% vs 93.9%). The 3-year graft survival rates were similar for long-distance-traveling liver grafts (donation after brainstem death: 85.5% vs 85.1%, donation after circulatory death: 81.0% vs 80.4%). Cubic spline regression analyses revealed that travel distance did not linearly worsen the prognosis of 3-year graft survival. On the other hand, younger donor age, lower donor body mass index, and shorter cold ischemic time mitigated the negative impact of 90-day graft survival in long-distance-traveling liver grafts.

CONCLUSION

The use of long-distance-traveling liver grafts negatively impacts 90-day graft survival but not 3-year graft survival. Moreover, long-distance-traveling liver grafts are more feasible with appropriate donor and recipient factors offsetting the extended cold ischemic time. Mechanical perfusion can improve long-distance-traveling liver graft use. Enhanced collaboration between organ procurement organizations and transplant centers and optimized transportation systems are essential for increasing long-distance-traveling liver graft use, ultimately expanding the donor pool.

The short and long-term prognostic influences of liver grafts with high bilirubin levels at the time of organ recovery

BACKGROUND

Donors with hyperbilirubinemia are often not utilized for liver transplantation (LT) due to concerns about potential liver dysfunction and graft survival. The potential to mitigate organ shortages using such donors remains unclear.

METHODS

This study analyzed adult deceased donor data from the United Network for Organ Sharing database (2002-2022). Hyperbilirubinemia was categorized as high total bilirubin (3.0-5.0 mg/dL) and very high bilirubin (≥5.0 mg/dL) in brain-dead donors. We assessed the impact of donor hyperbilirubinemia on 3-month and 3-year graft survival, comparing these outcomes to donors after circulatory death (DCD).

RESULTS

Of 138 622 donors, 3452 (2.5%) had high bilirubin and 1999 (1.4%) had very high bilirubin levels. Utilization rates for normal, high, and very high bilirubin groups were 73.5%, 56.4%, and 29.2%, respectively. No significant differences were found in 3-month and 3-year graft survival between groups. Donors with high bilirubin had superior 3-year graft survival compared to DCD (hazard ratio .83, p = .02). Factors associated with inferior short-term graft survival included recipient medical condition in intensive care unit (ICU) and longer cold ischemic time; factors associated with inferior long-term graft survival included older donor age, recipient medical condition in ICU, older recipient age, and longer cold ischemic time. Donors with ≥10% macrosteatosis in the very high bilirubin group were also associated with worse 3-year graft survival (p = .04).

DISCUSSION

The study suggests that despite many grafts with hyperbilirubinemia being non-utilized, acceptable post-LT outcomes can be achieved using donors with hyperbilirubinemia. Careful selection may increase utilization and expand the donor pool without negatively affecting graft outcome.

One size does not fit all: Differential benefits of simultaneous liver-kidney transplantation by eligibility criteria

Standard eligibility criteria for simultaneous liver-kidney transplantation (SLK) are in place in the United States. We hypothesize that the benefit associated with SLK over liver transplant alone differs by patient, depending on the specific SLK criteria met. We analyzed a retrospective US cohort of 5446 adult liver transplant or SLK recipients between January 1, 2015, and December 31, 2018, who are potentially qualified for SLK. Exposure was a receipt of SLK. We tested effect modification by the specific SLK eligibility criteria met (end-stage kidney disease, acute kidney injury, chronic kidney disease, or unknown). The primary outcome was death within 1 year of a liver transplant. We used a modified Cox regression analysis containing an interaction term of SLK * time from transplant. Two hundred ten (9%) SLK recipients and 351 (11%) liver-alone recipients died in 1 year. In the overall population, SLK was associated with a mortality benefit over liver transplant on the day of the transplant, without adjustment [HR: 0.59 (95% CI, 0.46-0.76)] and with adjustment [aHR: 0.50 (95% CI, 0.35-0.71)]. However, when SLK eligibility criteria were included, only in patients with end-stage kidney disease was SLK associated with a sustained survival benefit at day 0 [HR: 0.17 (0.08-0.35)] up to 288 (95% CI, 120-649) days post-transplant. Benefit within the first year post-transplant associated with SLK over liver-alone transplantation was only pronounced in patients with end-stage kidney disease but not present in patients meeting other criteria for SLK. A "strict SLK liberal Safety Net" strategy may warrant consideration at the national policy level.

Hepatitis C Screening in Post-Baby Boomer Generation Americans: One Size Does Not Fit All

OBJECTIVES

To analyze the impact of access to routine health care, as estimated by health insurance coverage, on hepatitis C virus (HCV) infection prevalence in US adults born after 1965 (post-baby boomer birth cohort [post-BBBC]) and to use the data to formulate strategies to optimize population screening for HCV.

PATIENTS AND METHODS

Adult examinees in the National Health and Nutrition Examination Survey with available anti-HCV data were divided into era 1 (1999-2008) and era 2 (2009-2016). The prevalence of HCV infection, as defined by detectable serum HCV RNA, was determined in post-BBBC adults. In low prevalence groups, prescreening modalities were considered to increase the pretest probability.

RESULTS

Of 16,966 eligible post-BBBC examinees, 0.5% had HCV infection. In both eras, more than 50% had no insurance. In era 2, HCV prevalence was 0.26% and 0.83% in those with and without insurance, respectively (P<.01). As a prescreening test, low alanine aminotransferase level (<23 U/L in women and 32 U/L in men) would identify 54% of post-BBBC adults with an extremely low (0.02%) HCV prevalence. Based on these data, a tiered approach that tests all uninsured directly for HCV and prescreens the insured with alanine aminotransferase would reduce the number to test by 56.5 million while missing less than 1% infections.

CONCLUSION

For HCV elimination, passive "universal" screening in routine health care settings is insufficient, although the efficiency of screening may be improved with alanine aminotransferase prescreening. Importantly, for individuals with limited access to health care, proactive outreach programs for HCV screening are still needed.

MELD 3.0 for adolescent liver transplant candidates

BACKGROUND AND AIMS

Adolescents constitute a unique waitlist cohort that is distinct from younger children. Model for End-stage Liver Disease (MELD) 3.0, which was developed in an adult population of liver transplant candidates, is planned to replace MELD-Sodium in the current liver allocation system for both adults and adolescents aged 12-17. We evaluated the predictive performance of MELD-Sodium, MELD 3.0, and Pediatric End-stage Liver Disease for 90-day waitlist mortality risk among adolescent liver transplant registrants.

APPROACH AND RESULTS

New waitlist registrations for primary liver transplants among individuals aged 12-17 and 18-25 for comparison were identified using Organ Procurement and Transplantation Network (OPTN) data from November 17, 2004, to December 31, 2021. The predictive performance of the current and proposed MELD and Pediatric End-stage Liver Disease scores was assessed using Harrell's concordance ( c ) statistic. There were 1238 eligible listings for adolescents aged 12-17 and 1740 young adults aged 18-25. In the adolescent group, 90-day survival was 97.8%, compared with 95.9% in those aged 18-25 (log-rank p = 0.005), with no significant differences when stratified by sex or indication. Among adolescents, increasing MELD 3.0 was associated with an increased hazard of mortality (HR=1.27, 95% CI: 1.18-1.37), and the c -statistic for 90-day waitlist survival using MELD 3.0 was 0.893 compared with 0.871 using MELD-Sodium and 0.852 using Pediatric End-stage Liver Disease.

CONCLUSIONS

The discriminative ability of MELD 3.0 to rank adolescents according to the risk of death within 90 days was robust. Although MELD 3.0 was initially developed and validated in adults, MELD 3.0 may also improve the prediction of waitlist mortality in adolescents and better represent their urgency for liver transplants.

OPTN/SRTR 2021 Annual Data Report: Liver

In 2021, liver transplant volume continued to grow, with a record 9,234 transplants performed in the United States, 8,665 (93.8%) from deceased donors and 569 (6.2%) from living donors. There were 8,733 (94.6%) adult and 501 (5.4%) pediatric liver transplant recipients. An increase in the number of deceased donor livers corresponded to an increase in the overall transplant rate and shorter waiting times, although still 10.0% of livers that were recovered were not transplanted. Alcohol-associated liver disease was the leading indication for both waitlist registration and liver transplant in adults, outpacing nonalcoholic steatohepatitis, while biliary atresia remained the leading indication for children. Related to allocation policy changes implemented in 2019, the proportion of liver transplants performed for hepatocellular carcinoma has decreased. Among adult candidates listed for liver transplant in 2020, 37.7% received a deceased donor liver transplant within 3 months, 43.8% within 6 months, and 53.3% within 1 year. Pretransplant mortality improved for children following implementation of acuity circle-based distribution. Short-term graft and patient survival outcomes up to 1 year worsened for adult deceased and living donor liver transplant recipients, which is a reversal of previous trends and coincided with the onset of the COVID-19 pandemic in early 2020. Longer-term outcomes among adult deceased donor liver transplant recipients were unaffected, with overall posttransplant mortality rates of 13.3% at 3 years, 18.6% at 5 years, and 35.9% at 10 years. Pretransplant mortality improved for children following implementation of acuity circle-based distribution and prioritization of pediatric donors to pediatric recipients in 2020. Pediatric living donor recipients had superior graft and patient survival outcomes compared with deceased donor recipients at all time points.

Impact of Donor Liver Macrovesicular Steatosis on Deceased Donor Yield and Posttransplant Outcome

BACKGROUND

The Scientific Registry of Transplant Recipients (SRTR) had not traditionally considered biopsy results in risk-adjustment models, yet biopsy results may influence outcomes and thus decisions regarding organ acceptance.

METHODS

Using SRTR data, which includes data on all donors, waitlisted candidates, and transplant recipients in the United States, we assessed (1) the impact of macrovesicular steatosis on deceased donor yield (defined as number of livers transplanted per donor) and 1-y posttransplant graft failure and (2) the effect of incorporating this variable into existing SRTR risk-adjustment models.

RESULTS

There were 21 559 donors with any recovered organ and 17 801 liver transplant recipients included for analysis. Increasing levels of macrovesicular steatosis on donor liver biopsy predicted lower organ yield: ≥31% macrovesicular steatosis on liver biopsy was associated with 87% to 95% lower odds of utilization, with 55% of these livers being discarded. The hazard ratio for graft failure with these livers was 1.53, compared with those with no pretransplant liver biopsy and 0% to 10% steatosis. There was minimal change on organ procurement organization-specific deceased donor yield or program-specific posttransplant outcome assessments when macrovesicular steatosis was added to the risk-adjustment models.

CONCLUSIONS

Donor livers with macrovesicular steatosis are disproportionately not transplanted relative to their risk for graft failure. To avoid undue risk aversion, SRTR now accounts for macrovesicular steatosis in the SRTR risk-adjustment models to help facilitate use of these higher-risk organs. Increased recognition of this variable may also encourage further efforts to standardize the reporting of liver biopsy results.

The steatosis-associated fibrosis estimator (SAFE) score: A tool to detect low-risk NAFLD in primary care

BACKGROUND

NAFLD is common in primary care. Liver fibrosis stage 2 or higher (≥F2) increases future risk of morbidity and mortality. We developed and validated a score to aid in the initial assessment of liver fibrosis for NAFLD in primary care.

METHODS

Data from patients with biopsy-proven NAFLD were extracted from the NASH Clinical Research Network observational study ( n = 676). Using logistic regression and machine-learning methods, we constructed prediction models to distinguish ≥F2 from F0/1. The models were tested in participants in a trial ("FLINT," n = 280) and local patients with NAFLD with magnetic resonance elastography data ( n = 130). The final model was applied to examinees in the National Health and Nutrition Examination Survey (NHANES) III ( n = 11,953) to correlate with long-term mortality.

RESULTS

A multivariable logistic regression model was selected as the Steatosis-Associated Fibrosis Estimator (SAFE) score, which consists of age, body mass index, diabetes, platelets, aspartate and alanine aminotransferases, and globulins (total serum protein minus albumin). The model yielded areas under receiver operating characteristic curves ≥0.80 in distinguishing F0/1 from ≥F2 in testing data sets, consistently higher than those of Fibrosis-4 and NAFLD Fibrosis Scores. The negative predictive values in ruling out ≥F2 at SAFE of 0 were 88% and 92% in the two testing sets. In the NHANES III set, survival up to 25 years of subjects with SAFE < 0 was comparable to that of those without steatosis ( p = 0.34), whereas increasing SAFE scores correlated with shorter survival with an adjusted HR of 1.53 ( p < 0.01) for subjects with SAFE > 100.

CONCLUSION

The SAFE score, which uses widely available variables to estimate liver fibrosis in patients diagnosed with NAFLD, may be used in primary care to recognize low-risk NAFLD.

Serum biomarkers of liver fibrosis identify globus pallidus vulnerability

The CNS manifestation of chronic liver disease can include magnetic resonance (MR) signal hyperintensities in basal ganglia structures. Here, relations between liver (serum-derived fibrosis scores) and brain (regional T1-weighted signal intensities and volumes) integrity were evaluated in a sample of 457 individuals including those with alcohol use disorders (AUD), people living with human immunodeficiency virus (HIV), those comorbid for AUD and HIV, and healthy controls. Liver fibrosis was identified from cutoff scores as follows: aspartate aminotransferase to platelet ratio index (APRI) > 0.7 in 9.4% (n = 43) of the cohort; fibrosis score (FIB4) > 1.5 in 28.0% (n = 128) of the cohort; and non-alcoholic fatty liver disease fibrosis score (NFS) > -1.4 in 30.2% (n = 138) of the cohort. Presence of serum-derived liver fibrosis was associated with high signal intensities selective to basal ganglia (i.e., caudate, putamen, and pallidum) structures. High signal intensities in the pallidum, however, explained a significant portion of the variance in APRI (25.0%) and FIB4 (23.6%) cutoff scores. Further, among the regions evaluated, only the globus pallidus showed a correlation between greater signal intensity and smaller volume (r = -0.44, p <.0001). Finally, higher pallidal signal intensity correlated worse ataxia (eyes open ρ = -0.23, p =.0002; eyes closed ρ = -0.21, p =.0005). This study suggests that clinically relevant serum biomarkers of liver fibrosis such as the APRI may identify individuals vulnerable to globus pallidus pathology and contribute to problems with postural balance.

"Beyond MELD" - Emerging strategies and technologies for improving mortality prediction, organ allocation and outcomes in liver transplantation

In this review article, we discuss the model for end-stage liver disease (MELD) score and its dual purpose in general and transplant hepatology. As the landscape of liver disease and transplantation has evolved considerably since the advent of the MELD score, we summarise emerging concepts, methodologies, and technologies that may improve mortality prognostication in the future. Finally, we explore how these novel concepts and technologies may be incorporated into clinical practice.

National Trends and Waitlist Outcomes of Locoregional Therapy Among Liver Transplant Candidates With Hepatocellular Carcinoma in the United States

BACKGROUND & AIMS

Policy changes in the United States have lengthened overall waiting times for patients with hepatocellular carcinoma (HCC). We investigated temporal trends in utilization of locoregional therapy (LRT) and associated waitlist outcomes among liver transplant (LT) candidates in the United States.

METHODS

Data for primary adult LT candidates listed from 2003 to 2018 who received HCC exception were extracted from the Organ Procurement and Transplantation Network database. Explant histology was examined, and multivariable competing risk analysis was used to evaluate the association between LRT type and waitlist dropout.

RESULTS

There were 31,609 eligible patients with at least 1 approved HCC exception, and 34,610 treatments among 24,145 LT candidates. The proportion with at least 1 LRT recorded increased from 42.3% in 2003 to 92.4% in 2018. Chemoembolization remains the most frequent type, followed by thermal ablation, with a notable increase in radioembolization from 3% in 2013 to 19% in 2018. An increased incidence of LRT was observed among patients with tumor burden beyond Milan criteria, higher α-fetoprotein level, and more compensated liver disease. Receipt of any type of LRT was associated with a lower risk of waitlist dropout; there was no significant difference by number of LRTs. In inverse probability of treatment weighting-adjusted analysis, radioembolization or ablation as the first LRT was associated with a reduced risk of waitlist dropout compared with chemoembolization.

CONCLUSIONS

In a large nationwide cohort of LT candidates with HCC, LRT, and in particular radioembolization, increasingly was used to bridge to LT. Patients with greater tumor burden and those with more compensated liver disease received more treatments while awaiting LT. Bridging LRT was associated with a lower risk of waitlist dropout.

OPTN/SRTR 2020 Annual Data Report: Liver

This year was marked by the COVID-19 pandemic, which altered transplant program activity and affected waitlist and transplant outcomes. Still, 8906 liver transplants were performed, an all-time high, across 142 centers in the United States, and pretransplant as well as graft and patient survival metrics, continued to improve. Living donation activity decreased after several years of growth. As of June 30, 2020, 98989 liver transplant recipients were alive with a functioning graft, and in the context of increasing liver transplant volume, the size of both the adult and pediatric liver transplant waitlists have decreased. On February 4, 2020, shortly before the pandemic began, a new liver distribution policy based on acuity circles was implemented, replacing donor service area- and region-based boundaries. A policy change to direct pediatric livers to pediatric recipients led to an increase in deceased donor transplant rates and a decrease in pretransplant mortality rate among children, although the absolute number of pediatric transplants did not increase in 2020. Among adults, alcohol-associated liver disease became the predominant indication for liver transplant in 2020. After implementation of the National Liver Review Board and lower waitlist priority for most exception cases in 2019, fewer liver transplants were being performed via exception points, and the transplant rate between those with and without hepatocellular carcinoma has equalized. Women continue to experience higher pretransplant mortality and lower rates of liver transplant than men.

MELD 3.0: The Model for End-Stage Liver Disease Updated for the Modern Era

BACKGROUND & AIMS

The Model for End-Stage Liver Disease (MELD) has been established as a reliable indicator of short-term survival in patients with end-stage liver disease. The current version (MELDNa), consisting of the international normalized ratio and serum bilirubin, creatinine, and sodium, has been used to determine organ allocation priorities for liver transplantation in the United States. The objective was to optimize MELD further by taking into account additional variables and updating coefficients with contemporary data.

METHODS

All candidates registered on the liver transplant wait list in the US national registry from January 2016 through December 2018 were included. Uni- and multivariable Cox models were developed to predict survival up to 90 days after wait list registration. Model fit was tested using the concordance statistic (C-statistic) and reclassification, and the Liver Simulated Allocation Model was used to estimate the impact of replacing MELDNa with the new model.

RESULTS

The final multivariable model was characterized by (1) additional variables of female sex and serum albumin, (2) interactions between bilirubin and sodium and between albumin and creatinine, and (3) an upper bound for creatinine at 3.0 mg/dL. The final model (MELD 3.0) had better discrimination than MELDNa (C-statistic, 0.869 vs 0.862; P < .01). Importantly, MELD 3.0 correctly reclassified a net of 8.8% of decedents to a higher MELD tier, affording them a meaningfully higher chance of transplantation, particularly in women. In the Liver Simulated Allocation Model analysis, MELD 3.0 resulted in fewer wait list deaths compared to MELDNa (7788 vs 7850; P = .02).

CONCLUSION

MELD 3.0 affords more accurate mortality prediction in general than MELDNa and addresses determinants of wait list outcomes, including the sex disparity.

Preliminary Evidence for a Relationship between Elevated Plasma TNFα and Smaller Subcortical White Matter Volume in HCV Infection Irrespective of HIV or AUD Comorbidity

Classical inflammation in response to bacterial, parasitic, or viral infections such as HIV includes local recruitment of neutrophils and macrophages and the production of proinflammatory cytokines and chemokines. Proposed biomarkers of organ integrity in Alcohol Use Disorders (AUD) include elevations in peripheral plasma levels of proinflammatory proteins. In testing this proposal, previous work included a group of human immunodeficiency virus (HIV)-infected individuals as positive controls and identified elevations in the soluble proteins TNFα and IP10; these cytokines were only elevated in AUD individuals seropositive for hepatitis C infection (HCV). The current observational, cross-sectional study evaluated whether higher levels of these proinflammatory cytokines would be associated with compromised brain integrity. Soluble protein levels were quantified in 86 healthy controls, 132 individuals with AUD, 54 individuals seropositive for HIV, and 49 individuals with AUD and HIV. Among the patient groups, HCV was present in 24 of the individuals with AUD, 13 individuals with HIV, and 20 of the individuals in the comorbid AUD and HIV group. Soluble protein levels were correlated to regional brain volumes as quantified with structural magnetic resonance imaging (MRI). In addition to higher levels of TNFα and IP10 in the 2 HIV groups and the HCV-seropositive AUD group, this study identified lower levels of IL1β in the 3 patient groups relative to the control group. Only TNFα, however, showed a relationship with brain integrity: in HCV or HIV infection, higher peripheral levels of TNFα correlated with smaller subcortical white matter volume. These preliminary results highlight the privileged status of TNFα on brain integrity in the context of infection.

OPTN/SRTR 2019 Annual Data Report: Liver

This year was notable for changes to exception points determined by the geographic median allocation Model for End-Stage Liver Disease (MELD) and implementation of the National Liver Review Board, which took place on May 14, 2019. The national acuity circle liver distribution policy was also implemented but reverted to donor service area- and region-based boundaries after 1 week. In 2019, growth continued in the number of new waiting list registrations (12,767) and transplants performed (8,896), including living-donor transplants (524). Compared with 2018, living-donor liver transplants increased 31%. Women continued to have a lower deceased-donor transplant rate and a higher pretransplant mortality rate than men. The median waiting time for candidates with a MELD of 15-34 decreased, while the number of transplants performed for patients with exception points decreased. These changes may have been related to the policy changes that took effect in May 2019, which increased waiting list priority for candidates without exception status. Hepatitis C continued to decline as an indication for liver transplant, as the proportion of liver transplant recipients with alcohol-related liver disease and clinical profiles consistent with non-alcoholic steatohepatitis increased. Graft and patient survival have improved despite changing recipient demographics including older age, higher MELD, and higher prevalence of obesity and diabetes.

Center Variation in Intention-to-Treat Survival Among Patients Listed for Liver Transplant

In the United States, centers performing liver transplant (LT) are primarily evaluated by patient survival within 1 year after LT, but tight clustering of outcomes allows only a narrow window for evaluation of center variation for quality improvement. Alternate measures more relevant to patients and the transplant community are needed. We examined adults listed for LT in the United States, using data submitted to the Scientific Registry of Transplant Recipients. Intention-to-treat (ITT) survival was defined as survival within 1 year from listing, regardless of transplant. Mixed effects/frailty models were used to assess center variation in ITT survival. Between January 2010 and December 2016, there were 66,428 new listings at 113 centers. Overall, median 1-year ITT survival was 79.8% (interquartile range [IQR], 76.1%-83.4%), whereas 1-year waiting-list (WL) survival was 75.8% (IQR, 71.2%-79.4%), and 1-year post-LT survival was 90.0% (IQR, 87.9%-91.8%). Higher rates of ITT mortality were correlated with increased WL mortality (correlation, r = 0.76), increased post-LT mortality (r = 0.31), lower volume centers (r = -0.34), and lower transplant rate ratio (r = -0.25). Similar patterns were observed in the subgroup of WL candidates listed with Model for End-Stage Liver Disease (MELD) ≥25: median 1-year ITT survival was 65.2% (IQR, 60.2%-72.6%), whereas 1-year post-LT survival was 87.5% (IQR, 84.0%-90.9%), and 1-year WL survival was 36.6% (IQR, 27.9%-47.0%). In mixed effects modeling, the transplant center was an independent predictor of ITT survival even after adjustment for age, sex, MELD, and sociodemographic variables. Center variation for ITT survival was larger compared with post-LT survival. The measurement of ITT outcome offers a complementary method to assess center performance. This is a first step toward understanding differences in program quality beyond patient and graft survival after LT.

Outcomes of Liver Transplantation Among Older Recipients With Nonalcoholic Steatohepatitis in a Large Multicenter US Cohort: the Re-Evaluating Age Limits in Transplantation Consortium

The liver transplantation (LT) population is aging, with the need for transplant being driven by the growing prevalence of nonalcoholic steatohepatitis (NASH). Older LT recipients with NASH may be at an increased risk for adverse outcomes after LT. Our objective is to characterize outcomes in these recipients in a large multicenter cohort. All primary LT recipients ≥65 years from 2010 to 2016 at 13 centers in the Re-Evaluating Age Limits in Transplantation (REALT) consortium were included. Of 1023 LT recipients, 226 (22.1%) were over 70 years old, and 207 (20.2%) had NASH. Compared with other LT recipients, NASH recipients were older (68.0 versus 67.3 years), more likely to be female (47.3% versus 32.8%), White (78.3% versus 68.0%), Hispanic (12.1% versus 9.2%), and had higher Model for End-Stage Liver Disease-sodium (21 versus 18) at LT (P < 0.05 for all). Specific cardiac risk factors including diabetes with or without chronic complications (69.6%), hypertension (66.3%), hyperlipidemia (46.3%), coronary artery disease (36.7%), and moderate-to-severe renal disease (44.4%) were highly prevalent among NASH LT recipients. Graft survival among NASH patients was 90.3% at 1 year and 82.4% at 3 years compared with 88.9% at 1 year and 80.4% at 3 years for non-NASH patients (log-rank P = 0.58 and P = 0.59, respectively). Within 1 year after LT, the incidence of graft rejection (17.4%), biliary strictures (20.9%), and solid organ cancers (4.9%) were comparable. Rates of cardiovascular (CV) complications, renal failure, and infection were also similar in both groups. We observed similar posttransplant morbidity and mortality outcomes for NASH and non-NASH LT recipients. Certain CV risk factors were more prevalent in this population, although posttransplant outcomes within 1 year including CV events and renal failure were similar to non-NASH LT recipients.

Trends in EMR for nonmalignant colorectal polyps in the United States

BACKGROUND AND AIMS

Although most large nonpedunculated colorectal lesions can be safely and efficaciously removed using EMR, the use of colectomy for benign colorectal lesions appears to be increasing. The reason(s) is unclear. We aimed to determine the use and adverse events of EMR in the United States.

METHODS

We used Optum's de-identified Clinformatics Data Mart Database (2003-2016), a database from a large national insurance provider, to identify all colonoscopies performed with either EMR or simple polypectomy on adult patients from January 1, 2011 to December 31, 2015. We measured time trends, regional variation, and adverse event rates. We assessed risk factors for adverse events using multivariate logistic regression.

RESULTS

The rate of EMR use in the US increased from 1.62% of all colonoscopies in 2011 to 2.48% of colonoscopies in 2015 (P < .001). There were, however, significant regional differences in the use of EMRs, from 2.4% of colonoscopies in the western United States to 2.0% of colonoscopies in the southern United States. Between 2011 and 2015, we found stable rates of perforation, GI bleeding (GIB), infections, and cardiac adverse events and decreasing rates of admissions after EMR. In our multivariate model, EMR was an independent risk factor for adverse events, albeit the rates of adverse events were low (1.35% GIB, .22% perforation).

CONCLUSIONS

Use of EMR is rising in the United States, although there is significant regional variation. The rates of adverse events after EMR and polypectomies were low and stable, confirming the continued safety of EMR procedures. A better understanding of the regional barriers and facilitators may improve the use of EMR as the standard management for benign colorectal lesions throughout the United States.

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 transplantation for hepatitis C virus (HCV) non-viremic recipients with HCV viremic donors

In the context of organ shortage, the opioid epidemic, and effective direct-acting antiviral (DAA) therapy for hepatitis C virus (HCV), more HCV-infected donor organs may be used for liver transplantation. Current data regarding outcomes after donor-derived HCV in previously non-viremic liver transplant recipients are limited. Clinical data for adult liver transplant recipients with donor-derived HCV infection from March 2017 to January 2018 at our institution were extracted from the medical record. Ten patients received livers from donors known to be infected with HCV based on positive nucleic acid testing. Seven had a prior diagnosis of HCV and were treated before liver transplantation. All recipients were non-viremic at the time of transplantation. All 10 recipients derived hepatitis C infection from their donor and achieved sustained virologic response at 12 weeks posttreatment with DAA-based regimens, with a median time from transplant to treatment initiation of 43 days (IQR 20-59). There have been no instances of graft loss or death, with median follow-up of 380 days (IQR 263-434) posttransplant. Transplantation of HCV-viremic livers into non-viremic recipients results in acceptable short-term outcomes. Such strategies may be used to expand the donor pool and increase access to liver transplantation.

De Novo Hepatocellular Carcinoma Among Liver Transplant Registrants in the Direct Acting Antiviral Era

The risk of hepatocellular carcinoma (HCC) in patients with hepatitis C virus (HCV) receiving direct acting antivirals (DAAs) has been debated. This study aims to describe the incidence of HCC among patients listed for liver transplantation (LT) in the DAA era. Individuals with cirrhosis listed for LT from January 2003 to December 2015 were identified using the Scientific Registry for Transplant Recipients database. Patients with HCC at listing or HCC exception within 180 days were excluded. Patients were divided into three eras based on listing date: eras 1 (2003-2010), 2 (2011-2013), and 3 (2014-2015). Incidence rates of HCC were calculated by era and compared using incident rate ratios (IRRs). The association between HCC and listing era was evaluated using Cox regression and competing risk analyses, the latter considering death and LT as competing events. Of the 48,158 eligible wait-list registrants, 3112 (6.5%) received HCC exceptions after a median of 493 days. In 20,039 individuals with HCV, the incidence of HCC was 49% higher in era 3 versus era 1 (IRR 1.49, 95% confidence interval [CI] 1.24-1.79). In multivariate analysis, those in era 3 had a higher hazard of HCC compared with era 1 (hazard ratio 1.22, 95% CI 1.01-1.48). However, in multivariable competing risks analysis, with death and LT considered as competing events for de novo HCC, era was no longer associated with HCC (subdistribution hazard ratio 0.83, 95% CI 0.69-1.00).

CONCLUSION

In this large population-based cohort of LT registrants, the incidence of HCC among HCV patients has increased in the DAA era. Competing risks analysis suggests that this may be explained by changes in rates of LT and wait-list mortality in the HCV population during this time. (Hepatology 2018; 00:000-000).

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).

Outcomes for liver transplant candidates listed with low model for end-stage liver disease score

The Model for End-Stage Liver Disease (MELD) score, which estimates mortality within 90 days, determines priority for liver transplantation (LT). However, longer-term outcomes on the wait list for patients who are initially listed with low MELD scores are not well characterized. All adults listed for primary LT at a single, high-volume center from 2005 to 2012 with an initial laboratory MELD score of 22 or lower were evaluated. Excluded were those patients listed with MELD exception points who underwent living donor liver transplantation (LDLT) or transplantation at another center, or who were removed from the wait list for nonmedical reasons. Outcomes and causes of death were identified by United Network for Organ Sharing, the National Death Index, and an electronic medical record review. Multivariate competing risk analysis evaluated predictors of death compared to deceased donor liver transplantation (DDLT); 893 patients were listed from 2005 to 2012. By the end of follow-up, 27% had undergone DDLT, and 31% were removed from the wait list for death or clinical deterioration. In a competing risks assessment, only MELD score of 6-9, older age, lower serum albumin, lower body mass index, and diabetes conferred an increased risk of wait-list dropout compared to DDLT. Listing for simultaneous liver-kidney transplantation was protective against wait-list dropout. Of the patients included, 275 patients died or were delisted for being too sick; 87% of the identifiable causes of death were directly related to end-stage liver disease or hepatocellular carcinoma. In conclusion, patients with low listing MELD scores remain at a significant risk for death due to liver-related causes and may benefit from early access to transplantation, such as LDLT or acceptance of high-risk donor livers. Predictors of death compared to transplantation may allow for early identification of patients who are at risk for wait-list mortality.

Liver fibrosis in elderly cadavers: localization of collagen types I, III, and IV, α-smooth muscle actin, and elastic fibers

We have shown a high prevalence of liver fibrosis in elderly cadavers with diverse causes of death by Sirius red stain; however, the various collagen types in these samples have yet to be evaluated. To further characterize the histopathology of the fibrotic lesions in the livers of these elderly cadavers, this study used immunohistochemistry and histochemistry to identify the principal collagens produced in liver fibrosis, fibrogenic cells and elastic fibers. Collagen I and III immunoreactions were found to colocalize in collagen fibers of fibrotic central veins, perisinusoidal fibrotic foci, portal tract stroma, and fibrous septa. α-Smooth muscle actin-expressing perisinusoidal hepatic stellate cells (HSCs), as well as perivenular, portal, and septal myofibroblasts, were closely associated with collagen fibers, reflecting their fibrogenic functions. HSCs and myofibroblasts were also noted to express collagen IV, which may contribute to production of basal lamina-like structures. In fibrotic livers, the sinusoidal lining showed variable immunostaining for collagen IV. Collagen IV immunostaining revealed vascular proliferation and atypical ductular reaction at the portal-septal parenchymal borders, as well as capillary-like vessels in the lobular parenchyma. While elastic fibers were absent in the space of Disse, they were found to codistribute with collagens in portal tracts, fibrous septa and central veins. Our combined assessment of collagen types, HSCs, myofibroblasts, and elastic fibers is significant in understanding the histopathology of fibrosis in the aging liver.

Downregulation of hepatic stellate cell activation by retinol and palmitate mediated by adipose differentiation-related protein (ADRP)

Hepatic stellate cells (HSCs) store retinoids and triacylglycerols in cytoplasmic lipid droplets. Two prominent features of HSC activation in liver fibrosis are loss of lipid droplets along with increase of alpha-smooth muscle actin (alpha-SMA), but the link between these responses and HSC activation remains elusive. In non-adipose cells, adipose differentiation-related protein (ADRP) coats lipid droplets and regulates their formation and lipolysis; however its function in HSCs is unknown. Here, we observed, in human liver sections or primary HSC culture, ADRP localization to lipid droplets of HSCs, and reduced staining coincident with loss of lipid droplets in liver fibrosis and in culture-activated HSCs, consistent with HSC activation. In the LX-2 human immortalized HSCs, with scant lipid droplets and features of activated HSCs, we found that the upregulation of ADRP mRNA by palmitate is potentiated by retinol, accompanied by increased ADRP protein, generation of retinyl palmitate, and lipid droplet formation. ADRP induction also led to decreased expression of alpha-SMA mRNA and its protein, while ADRP knockdown with small interfering RNA (siRNA) normalized alpha-SMA expression. Furthermore, ADRP induction by retinol and palmitate resulted in decreased expression of collagen I and matrix metalloproteinase-2 mRNA, fibrogenic genes associated with activated HSCs, while increasing matrix metalloproteinase-1 mRNA; ADRP knockdown with siRNA reversed these changes. Tissue inhibitor of metalloproteinase-1 was not affected. Thus, ADRP upregulation mediated by retinol and palmitate promotes downregulation of HSC activation and is functionally linked to the expression of fibrogenic genes.