Banff 2022 Liver Group Meeting report: Monitoring long-term allograft health.

The Banff Working Group on Liver Allograft Pathology met in September 2022. Participants included hepatologists, surgeons, pathologists, immunologists, and histocompatibility specialists. Presentations and discussions focused on the evaluation of long-term allograft health, including noninvasive and tissue monitoring, immunosuppression optimization, and long-term structural changes. Potential revision of the rejection classification scheme to better accommodate and communicate late T cell-mediated rejection patterns and related structural changes, such as nodular regenerative hyperplasia, were discussed. Improved stratification of long-term maintenance immunosuppression to match the heterogeneity of patient settings will be central to improving long-term patient survival. Such personalized therapeutics are in turn contingent on a better understanding and monitoring of allograft status within a rational decision-making approach, likely to be facilitated in implementation with emerging decision-support tools. Proposed revisions to rejection classification emerging from the meeting include the incorporation of interface hepatitis and fibrosis staging. These will be opened to online testing, modified accordingly, and subject to consensus discussion leading up to the next Banff conference.

Impact of early immunosuppression on pediatric liver transplant outcomes within 1 year.

OBJECTIVES: The Starzl Network for Excellence in Pediatric Transplantation identified optimizing immunosuppression (IS) as a priority practice improvement area for patients, families, and providers. We aimed to evaluate associations between clinical characteristics, early IS, and outcomes. METHODS: We analyzed pediatric liver transplant (LT) data from 2013 to 2018 in the United Network for Organ Sharing (UNOS) and the Society of Pediatric Liver Transplantation (SPLIT) registries. RESULTS: We included 2542 LT recipients in UNOS and 1590 in SPLIT. IS choice varied between centers with steroid induction and mycophenolate mofetil (MMF) use each ranging from 0% to 100% across centers. Clinical characteristics associated with early IS choice were inconsistent between the two data sets. T-cell depleting antibody use was associated with improved 1-year graft (hazard ratio [HR] 0.50, 95% confidence interval [CI] 0.34-0.76) and patient (HR 0.40, 95% CI 0.20-0.79) survival in UNOS but decreased 1-year patient survival (HR 4.12, 95% CI 1.31-12.93) and increased acute rejection (HR 1.58, 95% CI 1.07-2.34) in SPLIT. Non-T-cell depleting antibody use was not associated with differential risk of survival nor rejection. MMF use was associated with improved 1-year graft survival (HR 0.73, 95% CI 0.54-0.99) in UNOS only. CONCLUSIONS: Variation exists in center choice of early IS regimen. UNOS and SPLIT data provide conflicting associations between IS and outcomes in multivariable analysis. These results highlight the need for future multicenter collaborative work to identify evidence-based IS best practices.

Caregivers' and providers' perspectives of social and medical care after pediatric liver transplant: Results from the multicenter SOCIAL-Tx study.

Disparities exist in pediatric liver transplant (LT). We characterized barriers and facilitators to providing transplant and social care within pediatric LT clinics. This was a multicenter qualitative study. We oversampled caregivers reporting household financial strain, material economic hardship, or demonstrating poor health literacy. We also enrolled transplant team members. We conducted semistructured interviews with participants. Caregiver interviews focused on challenges addressing transplant and household needs. Transplant provider interviews focused on barriers and facilitators to providing social care within transplant teams. Interviews were recorded, transcribed, and coded according to the Capability, Opportunity, Motivation-Behavior model. We interviewed 27 caregivers and 27 transplant team members. Fifty-two percent of caregivers reported a household income <$60,000, and 62% reported financial resource strain. Caregivers reported experiencing (1) high financial burdens after LT, (2) added caregiving labor that compounds the financial burden, (3) dependency on their social network's generosity for financial and logistical support, and (4) additional support being limited to the perioperative period. Transplant providers reported (1) relying on the pretransplant psychosocial assessment for identifying social risks, (2) discomfort initiating social risk discussions in the post-transplant period, (3) reliance on social workers to address new social risks, and (4) social workers feeling overburdened by quantity and quality of the social work referrals. We identified barriers to providing effective social care in pediatric LT, primarily a lack of comfort in assessing and addressing new social risks in the post-transplant period. Addressing these barriers should enhance social care delivery and improve outcomes for these children.

Association of state Medicaid expansion policies with pediatric liver transplant outcomes.

Children from minoritized/socioeconomically deprived backgrounds suffer disproportionately high rates of uninsurance and graft failure/death after liver transplant. Medicaid expansion was developed to expand access to public insurance. Our objective was to characterize the impact of Medicaid expansion policies on long-term graft/patient survival after pediatric liver transplantation. All pediatric patients (<19 years) who received a liver transplant between January 1, 2005, and December 31, 2020 in the US were identified in the Scientific Registry of Transplant Recipients (N = 8489). Medicaid expansion was modeled as a time-varying exposure based on transplant and expansion dates. We used Cox proportional hazards models to evaluate the impact of Medicaid expansion on a composite outcome of graft failure/death over 10 years. As a sensitivity analysis, we conducted an intention-to-treat analysis from time of waitlisting to death (N = 1 1901). In multivariable analysis, Medicaid expansion was associated with a 30% decreased hazard of graft failure/death (hazard ratio, 0.70; 95% confidence interval, 0.62, 0.79; P < .001) after adjusting for Black race, public insurance, neighborhood deprivation, and living in a primary care shortage area. In intention-to-treat analyses, Medicaid expansion was associated with a 72% decreased hazard of patient death (hazard ratio, 0.28; 95% confidence interval, 0.23-0.35; P < .001). Policies that enable broader health insurance access may help improve outcomes and reduce disparities for children undergoing liver transplantation.

Ambient air pollution is associated with graft failure/death in pediatric liver transplant recipients.

Children exposed to disproportionately higher levels of air pollution experience worse health outcomes. In this population-based, observational registry study, we examine the association between air pollution and graft failure/death in children following liver transplantation (LT) in the US. We modeled the associations between air pollution (PM2.5) levels localized to the patient's ZIP code at the time of transplant and graft failure or death using Cox proportional-hazards models in pediatric LT recipients aged <19 years in the US from 2005-2015. In univariable analysis, high neighborhood PM2.5 was associated with a 56% increased hazard of graft failure/death (HR: 1.56; 95% CI: 1.32, 1.83; P < .001). In multivariable analysis, high neighborhood PM2.5 was associated with a 54% increased risk of graft failure/death (HR: 1.54; 95% CI: 1.29, 1.83; P < .001) after adjusting for race as a proxy for racism, insurance status, rurality, and neighborhood socioeconomic deprivation. Children living in high air pollution neighborhoods have an increased risk of graft failure and death posttransplant, even after controlling for sociodemographic variables. Our findings add further evidence that air pollution contributes to adverse health outcomes for children posttransplant and lay the groundwork for future studies to evaluate underlying mechanisms linking PM2.5 to adverse LT outcomes.

Caregiver Perceptions of Social Risk Screening in Pediatric Liver Transplantation: From the Multicenter SOCIAL-Tx Study.

BACKGROUND: The social determinants of health contribute to adverse post-liver transplant outcomes. Identifying unmet social risks may enable transplant teams to improve long-term outcomes for at-risk children. However, providers may feel uncomfortable asking about household-level social risks in the posttransplant period because they might make their patients/families uncomfortable. METHODS: We conducted a mixed-methods analysis of caregiver participants (ie, parents/guardians of pediatric liver transplant recipients) in the Social and Contextual Impact on Children Undergoing Liver Transplantation study to assess their perceptions of provider-based social risk screening. Participants (N = 109) completed a 20-min social determinants of health questionnaire that included questions on the acceptability of being asked intimate social risk questions. A subset of participants (N = 37) engaged in an in-depth qualitative interview to share their perceptions of social risk screening. RESULTS: Of 109 participants across 9 US transplant centers, 60% reported financial strain and 30% reported at least 1 material economic hardship (eg, food insecurity, housing instability). Overall, 65% of respondents reported it very or somewhat appropriate and 25% reported being neutral to being screened for social risks in a liver transplant setting. In qualitative analyses, participants reported trust in the providers and a clear understanding of the intention of the screening as prerequisites for liver transplant teams to perform social risk screening. CONCLUSIONS: Only a small minority of caregivers found social risk screening unacceptable. Pediatric liver transplant programs should implement routine social risk screening and prioritize the patient and family voices when establishing a screening program to ensure successful implementation.

Immunosuppression-Free Life after Pediatric Liver Transplant: A Case-Control Study from the Society of Pediatric Liver Transplant (SPLIT) Registry.

OBJECTIVE: To compare long-term outcomes of pediatric liver transplant (LT) recipients off immunosuppression (IS) with matched controls on IS using data from the Society of Pediatric Liver Transplant (SPLIT) registry. STUDY DESIGN: This was a retrospective case-control study. SPLIT participants <18 years of age, ≥4 years after isolated LT, and off IS for ≥1 year (cases) were age- and sex-matched 1:2 to patients with the same primary diagnosis and post-LT follow-up duration (controls). Primary outcomes included retransplantation, allograft rejection, IS comorbidities, and prevalence of SPLIT-derived composite ideal outcome (c-IO) achieved at the end of the follow-up period. Differences were compared using multiple linear regression for continuous outcomes and logistic regression for dichotomous data. RESULTS: The study cohort was composed of 33 cases (42.4% male, 60.6% biliary atresia, median age at LT of 0.7 [P25, P75, 0.5, 1.6] years, median IS withdrawal time of 9 [P25, P75, 6, 12] years after LT) and 66 age- and sex-matched controls. No cases required retransplantation. Cases and controls had similar growth parameters, laboratory values, calculated glomerular filtration rates, rates of post-transplant lymphoproliferative disease, graft rejection, and attainment of c-IO. CONCLUSIONS: No differences in allograft rejection rates, IS complications, or c-IO prevalence were seen between SPLIT patients off IS and age- and sex-matched controls remaining on IS. Discontinuation of IS most commonly occurred in the context of rigorously designed IS withdrawal trials. The available sample size was small, affecting generalizability to the broader pediatric LT population.

Mapping children by ALT 4-5 years after liver transplant: Potential individual and population applications.

INTRODUCTION: Although clinicians repeatedly measure ALT to assess allograft health in children with liver transplants, they generally make decisions based on single values or qualitative trends without quantitative aggregation or synthesis. We therefore aimed to derive and test a holistic ALT metric for the 5th post-transplant year (Yr 4-5) that may better guide clinical decision-making and/or population comparisons. METHODS: We derived the "adjusted mean Yr 4-5 ALT" for children transplanted in 2005-2016 by averaging the median ALT from each month. Patients in quartiles (Q1-4) defined by the adjusted mean Yr 4-5 ALT were compared by clinical variables, Yr 5-8 outcomes, and tacrolimus standard deviation (MLVI). RESULTS: For 97 children [49 male; 77 deceased donors; median (IQR) age at LT 2.5 (0.8-11.7) years], the 25th, 50th, and 75th percentile thresholds for adjusted mean Yr 4-5 ALT were 19, 28, and 47 U/L, respectively. Age, donor type, LT indication, rejection history, and mean tacrolimus levels did not differ between quartiles (Q). Children in Q4 had more Yr 4-5 acute rejection episodes (p < .01), higher Yr 4-5 MLVI (p < .01), and more Yr 5-8 for-cause liver biopsies (p < .01) than those in Q1 + Q2. Children in Q3 also had higher Yr 4-5 MLVI than Q1 + Q2 (p = .047). Rates of chronic rejection and therapeutic liver-related procedures were higher in Q4 but the difference did not reach significance. CONCLUSION: An integrated ALT metric calculated utilizing all available ALT values correlates with MLVI and future for-cause biopsies. Further study of this novel ALT metric as a predictor of clinical outcomes and descriptor of populations is warranted.

Balancing immunosuppression in pediatric liver transplantation: Playing the long game.

The overarching goal in the care of pediatric liver transplant recipients is to optimize allograft and patient health. Balancing immunosuppression to maintain allograft health while avoiding medication side effects is essential for long-term survival and optimal quality of life in pediatric liver transplant recipients. Utilizing precision medicine to personalize immunosuppression, which includes minimization and withdrawal, is core to this effort. The unique anatomy and physiology of the liver make it more tolerant to immune-mediated injury and a more favorable organ for immunosuppression minimization and withdrawal. However, several challenges exist. Standard biochemical values and histologic features may not reliably predict allograft health after a reduction in immunosuppression. Additionally, biochemical values alone do not reliably identify which patients can successfully develop operational tolerance, as there may be occult allograft injury despite normal liver enzymes. Finally, the durability of tolerance after successful reduction in immunosuppression remains uncertain over time. Innovative tools show promise in circumventing these challenges, but more research is needed to determine actual clinical utility. While immunosuppression-free transplant may not be a current reality for most pediatric liver transplant recipients, strategies to safely minimize immunosuppression without compromising allograft health are within reach. Each liver allograft and recipient pair requires a different degree of immune modulation, and through a structured process of minimization and withdrawal, immunosuppression can indeed be tailored in a precise, personalized way to optimize outcomes. This review focuses on the progress that has been made to individualize immunosuppression in pediatric liver transplantation to ensure optimal allograft and recipient health.