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.

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.

Epstein-Barr virus-associated post-transplant lymphoproliferative disorders in pediatric transplantation: A prospective multicenter study in the United States.

BACKGROUND: Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disorders (PTLD) is the most common malignancy in children after transplant; however, difficulties for early detection may worsen the prognosis. METHODS: The prospective, multicenter, study enrolled 944 children (≤21 years of age). Of these, 872 received liver, heart, kidney, intestinal, or multivisceral transplants in seven US centers between 2014 and 2019 (NCT02182986). In total, 34 pediatric EBV+ PTLD (3.9%) were identified by biopsy. Variables included sex, age, race, ethnicity, transplanted organ, EBV viral load, pre-transplant EBV serology, immunosuppression, response to chemotherapy and rituximab, and histopathological diagnosis. RESULTS: The uni-/multivariable competing risk analyses revealed the combination of EBV-seropositive donor and EBV-naïve recipient (D+R-) was a significant risk factor for PTLD development (sub-hazard ratio: 2.79 [1.34-5.78], p = .006) and EBV DNAemia (2.65 [1.72-4.09], p < .001). Patients with D+R- were significantly more associated with monomorphic/polymorphic PTLD than those with the other combinations (p = .02). Patients with monomorphic/polymorphic PTLD (n = 21) had significantly more EBV DNAemia than non-PTLD patients (p < .001) and an earlier clinical presentation of PTLD than patients with hyperplasias (p < .001), within 6-month post-transplant. Among non-liver transplant recipients, monomorphic/polymorphic PTLD were significantly more frequent than hyperplasias in patients ≥5 years of age at transplant (p = .01). CONCLUSIONS: D+R- is a risk factor for PTLD and EBV DNAemia and associated with the incidence of monomorphic/polymorphic PTLD. Intensive follow-up of EBV viral load within 6-month post-transplant, especially for patients with D+R- and/or non-liver transplant recipients ≥5 years of age at transplant, may help detect monomorphic/polymorphic PTLD early in pediatric transplant.

Optimizing the pediatric transplant candidate.

PURPOSE OF REVIEW: Advances in pediatric transplant parallel those in adult populations; however, there remain critical unique considerations and differences that require specialized knowledge and a specific skill set to optimize care afforded to the pediatric transplant candidate. We introduce general themes regarding optimization of the transplant candidate that are unique to children. RECENT FINDINGS: The pathologies leading to pediatric organ transplant candidacy differ from adults and a precise understanding of the physiologies and natural histories of such diseases is critical for optimized care. Regardless of etiology, comorbidities including malnutrition, sarcopenia, and developmental delay are seen and often require disease and organ specific approaches to management. Additionally, an understanding of the concepts of developmental immunology and their relevance to transplant is critical. SUMMARY: When looking to optimize pretransplant care, awareness of the pediatric-specific challenges by the transplant community in addition to organ- and age-specific management strategies enable the best outcomes for children awaiting solid organ transplantation.

Distinct association between chronic Epstein-Barr virus infection and T cell compartments from pediatric heart, kidney, and liver transplant recipients.

Chronic Epstein-Barr virus (EBV) infection after pediatric organ transplantation (Tx) accounts for significant morbidity and mortality. The risk of complications, such as posttransplant lymphoproliferative disorders, in high viral load (HVL) carriers is the highest in heart Tx recipients. However, the immunologic signatures of such a risk have been insufficiently defined. Here, we assessed the phenotypic, functional, and transcriptomic profiles of peripheral blood CD8+/CD4+ T cells, including EBV-specific T cells, in 77 pediatric heart, kidney, and liver Tx recipients and established the relationship between memory differentiation and progression toward exhaustion. Unlike kidney and liver HVL carriers, heart HVL carriers displayed distinct CD8+ T cells with (1) up-regulation of interleukin-21R, (2) decreased naive phenotype and altered memory differentiation, (3) accumulation of terminally exhausted (TEX PD-1+T-bet-Eomes+) and decrease of functional precursors of exhausted (TPEX PD-1intT-bet+) effector subsets, and (4) transcriptomic signatures supporting the phenotypic changes. In addition, CD4+ T cells from heart HVL carriers displayed similar changes in naive and memory subsets, elevated Th1 follicular helper cells, and plasma interleukin-21, suggesting an alternative inflammatory mechanism that governs T cell responses in heart Tx recipients. These results may explain the different incidences of EBV complications and may help improve the risk stratification and clinical management of different types of Tx recipients.

Mutations in latent membrane protein 1 of Epstein-Barr virus are associated with increased risk of posttransplant lymphoproliferative disorder in children.

Epstein-Barr virus (EBV)-positive posttransplant lymphoproliferative disorder (PTLD) results in significant morbidity and mortality in pediatric transplant recipients. Identifying individuals at an increased risk of EBV-positive PTLD could influence clinical management of immunosuppression and other therapies, improving posttransplant outcomes. A 7-center prospective, observational clinical trial of 872 pediatric transplant recipients evaluated the presence of mutations at positions 212 and 366 of EBV latent membrane protein 1 (LMP1) as an indicator of risk of EBV-positive PTLD (clinical trials: NCT02182986). DNA was isolated from peripheral blood of EBV-positive PTLD case patients and matched controls (1:2 nested case:control), and the cytoplasmic tail of LMP1 was sequenced. Thirty-four participants reached the primary endpoint of biopsy-proven EBV-positive PTLD. DNA was sequenced from 32 PTLD case patients and 62 matched controls. Both LMP1 mutations were present in 31 of 32 PTLD cases (96.9%) and in 45 of 62 matched controls (72.6%) (P = .005; OR = 11.7; 95% confidence interval, 1.5, 92.6). The presence of both G212S and S366T carries a nearly 12-fold increased risk of development of EBV-positive PTLD. Conversely, transplant recipients without both LMP1 mutations carry a very low risk of PTLD. Analysis of mutations at positions 212 and 366 of LMP1 can be informative in stratifying patients for risk of EBV-positive PTLD.

Center use of technical variant grafts varies widely and impacts pediatric liver transplant waitlist and recipient outcomes in the United States.

To assess the impact of technical variant grafts (TVGs) [including living donor (LD) and deceased donor split/partial grafts] on waitlist (WL) and transplant outcomes for pediatric liver transplant (LT) candidates, we performed a retrospective analysis of Organ Procurement and Transplantation Network (OPTN) data on first-time LT or liver-kidney pediatric candidates listed at centers that performed >10 LTs during the study period, 2004-2020. Center variance was plotted for LT volume, TVG usage, and survival. A composite center metric of TVG usage and WL mortality was developed to demonstrate the existing variation and potential for improvement. Sixty-four centers performed 7842 LTs; 657 children died on the WL. Proportions of WL mortality by center ranged from 0% to 31% and those of TVG usage from 0% to 76%. Higher TVG usage, from deceased donor or LD, independently or in combination, significantly correlated with lower WL mortality. In multivariable analyses, death from listing was significantly lower with increased center TVG usage (HR = 0.611, CI: 0.40-0.92) and LT volume (HR = 0.995, CI: 0.99-1.0). Recipients of LD transplants (HR = 0.637, CI: 0.51-0.79) had significantly increased survival from transplant compared with other graft types, and recipients of deceased donor TVGs (HR = 1.066, CI: 0.93-1.22) had statistically similar outcomes compared with whole graft recipients. Increased TVG utilization may decrease WL mortality in the US. Hence, policy and training to increase TVG usage, availability, and expertise are critical.

State of pediatric liver transplantation in the United States and achieving zero wait list mortality with ideal outcomes: A statement from the Starzl Network for Excellence in Pediatric Transplant Surgeon's Working Group.

BACKGROUND: Liver transplant is a life-saving therapy that can restore quality life for several pediatric liver diseases. However, it is not available to all children who need one. Expertise in medical and surgical management is heterogeneous, and allocation policies are not optimally serving children. Technical variant grafts from both living and deceased donors are underutilized. METHODS: Several national efforts in pediatric liver transplant to improve access to and outcomes from liver transplant for children have been instituted and include adjustments to allocation policies, UNOS-sponsored collaborative improvement projects, and the emergence of national learning networks to study ongoing challenges in the field the Surgical Working group of the Starzl Network for Excellence in Pediatric Transplantation (SNEPT) discusses key issues and proposes potential solutions to eliminate the persistent wait list mortality that pediatric patients face. RESULTS: A discussion of the factors impacting pediatric patients' access to liver transplant is undertaken, along with a proposal of several measures to ensure equitable access to life-saving liver transplant. CONCLUSIONS: Pediatric liver transplant wait list mortality can and should be eliminated. Several measures, including collaborative efforts among centers, could be leveraged to acheive this goal.

Impact of the acuity circle model for liver allocation on multivisceral transplant candidates.

Liver allocation was updated on February 4, 2020, replacing a Donor Service Area (DSA) with acuity circles (AC). The impact on waitlist outcomes for patients listed for combined liver-intestine transplantation (multivisceral transplantation [MVT]) remains unknown. The Organ Procurement and Transplantation Network/United Network for Organ Sharing database was used to identify all candidates listed for both liver and intestine between January 1, 2018 and March 5, 2021. Two eras were defined: pre-AC (2018-2020) and post-AC (2020-2021). Outcomes included 90-day waitlist mortality and transplant probability. A total of 127 adult and 104 pediatric MVT listings were identified. In adults, the 90-day waitlist mortality was not statistically significantly different, but transplant probability was lower post-AC. After risk-adjustment, post-AC was associated with a higher albeit not statistically significantly different mortality hazard (sub-distribution hazard ratio[sHR]: 8.45, 95% CI: 0.96-74.05; p = .054), but a significantly lower transplant probability (sHR: 0.33, 95% CI: 0.15-0.75; p = .008). For pediatric patients, waitlist mortality and transplant probability were similar between eras. The proportion of patients who underwent transplant with exception points was lower post-AC both in adult (44% to 9%; p = .04) and pediatric recipients (65% to 15%; p = .002). A lower transplant probability observed in adults listed for MVT may ultimately result in increased waitlist mortality. Efforts should be taken to ensure equitable organ allocation in this vulnerable patient population.

Predictors of survival following liver transplantation for pediatric hepatoblastoma and hepatocellular carcinoma: Experience from the Society of Pediatric Liver Transplantation (SPLIT).

Management of unresectable pediatric hepatoblastoma (HB) and hepatocellular carcinoma (HCC) remains challenging. The Society of Pediatric Liver Transplantation (SPLIT) database was used to study survival predictors in pediatric liver transplantation (LT) for HB and HCC. Event-free survival (EFS), associated risk factors, and postoperative complications were studied in children requiring LT for HB/HCC at 16 SPLIT centers. Three-year EFS was 81% for HB (n = 157) and 62% for HCC (n = 18) transplants. Of HB transplants, 6.9% were PRETEXT II and 15.3% were POST-TEXT I/II. Tumor extent did not impact survival (p = NS). Salvage (n = 13) and primary HB transplants had similar 3-year EFS (62% versus 78%, p = NS). Among HCC transplants, 3-year EFS was poorer in older patients (38% in ≥8-year-olds vs 86% <8-year-olds) and those with larger tumors (48% for those beyond versus 83% within Milan criteria, p = NS). Risk of infection (HR 1.5, 95% CI 1.1-2.2, p = .02) and renal injury (HR 2.4, 95% CI 1.7-3.3, p < .001) were higher in malignant versus nonmalignant LT. Survival is favorable for pediatric HB and HCC LT, including outcomes after salvage transplant. Unexpected numbers of LTs occurred in PRE/POST-TEXT I/II tumors. Judicious patient selection is critical to distinguish tumors that are potentially resectable; simultaneously, we must advocate for patients with unresectable malignancies to receive organs.

Factors associated with improved patient and graft survival beyond 1 year in pediatric liver transplantation.

With advances in surgical techniques, medical management, and more equitable allocation systems, children who receive a liver transplantation (LT) today can expect remarkable outcomes early after LT. However, beyond 1 year after transplant, attrition rates have not improved. We reviewed two separate eras (Era 1: January 1995-June 2004 vs. Era 2: July 2004-March 2018) of the Society of Pediatric Liver Transplantation registry to explore the evolution and associated factors contributing to late graft loss (LGL) and late mortality (LM). The fraction of long-term pediatric LT recipients surviving after 1 year with their first graft significantly improved (81.5% in Era 1 vs. 85.7% in Era 2; p < 0.0001). This improvement occurred despite significant changes in patient selection toward higher risk populations (p < 0.001) and without notable improvement in perioperative complications such as hepatic artery thrombosis (p = 0.24) and early posttransplant reoperation (p = 0.94) that have historically contributed to poor late-allograft outcomes. Improved outcomes were associated with changes in patient characteristics and perioperative practices, which subsequently impacted both early post-LT complications as well as other sequalae known to contribute to adverse events in long-term pediatric LT recipients. In conclusion, despite significant changes in patient selection toward higher risk populations, and without notable improvement in several perioperative complications known to contribute to poor late-allograft outcomes, significant improvements in LGL and a trend toward improvement in LM was seen in a more contemporary cohort of children receiving an LT.

Efficacy and Safety of Immunosuppression Withdrawal in Pediatric Liver Transplant Recipients: Moving Toward Personalized Management.

BACKGROUND AND AIMS: Tolerance is transplantation's holy grail, as it denotes allograft health without immunosuppression and its toxicities. Our aim was to determine, among stable long-term pediatric liver transplant recipients, the efficacy and safety of immunosuppression withdrawal to identify operational tolerance. APPROACH AND RESULTS: We conducted a multicenter, single-arm trial of immunosuppression withdrawal over 36-48 weeks. Liver tests were monitored biweekly (year 1), monthly (year 2), and bimonthly (years 3-4). For-cause biopsies were done at investigators' discretion but mandated when alanine aminotransferase or gamma glutamyltransferase exceeded 100 U/L. All subjects underwent final liver biopsy at trial end. The primary efficacy endpoint was operational tolerance, defined by strict biochemical and histological criteria 1 year after stopping immunosuppression. Among 88 subjects (median age 11 years; 39 boys; 57 deceased donor grafts), 33 (37.5%; 95% confidence interval [CI] 27.4%, 48.5%) were operationally tolerant, 16 were nontolerant by histology (met biochemical but failed histological criteria), and 39 were nontolerant by rejection. Rejection, predicted by subtle liver inflammation in trial entry biopsies, typically (n = 32) occurred at ≤32% of the trial-entry immunosuppression dose and was treated with corticosteroids (n = 32) and/or tacrolimus (n = 38) with resolution (liver tests within 1.5 times the baseline) for all but 1 subject. No death, graft loss, or chronic, severe, or refractory rejection occurred. Neither fibrosis stage nor the expression level of a rejection gene set increased over 4 years for either tolerant or nontolerant subjects. CONCLUSIONS: Immunosuppression withdrawal showed that 37.5% of selected pediatric liver-transplant recipients were operationally tolerant. Allograft histology did not deteriorate for either tolerant or nontolerant subjects. The timing and reversibility of failed withdrawal justifies future trials exploring the efficacy, safety, and potential benefits of immunosuppression minimization.

Sarcopenia prevalence in pediatric intestinal transplant recipients: Implications on post-transplant outcomes.

BACKGROUND: Sarcopenia has been associated with poor surgical outcomes but has not been studied in pediatric intestinal transplantation. We aimed to determine sarcopenia prevalence in intestinal transplant recipients and the association of sarcopenia with outcomes. METHODS: We performed a cross-sectional retrospective chart review of intestinal transplant recipients from 2000-present. We estimated total psoas muscle area (tPMA) at L3-L4 and L4-L5 from computed tomography scans prior to or in the immediate peri-operative period. Sarcopenia was defined by tPMA below the 5th percentile for age and sex. We built a Cox-proportional hazards model to determine the association between sarcopenia and patient and graft survival. RESULTS: Of the 56 intestinal transplant recipients included, 36 (64%) were sarcopenic. Graft survival was 79% at one year and 59% at five years. Overall patient survival was 86% at one year and 76% at five years. Peri-transplant sarcopenia was associated with improved graft survival (Hazard ratio 0.42, 95% confidence interval: 0.20-0.88) but not overall survival (Hazard ratio 0.47, 95% confidence interval: 0.19-1.20). CONCLUSIONS: In this first report of sarcopenia in pediatric intestinal transplant, we found a high sarcopenia prevalence without an association with worse outcomes. The potential improved graft survival in sarcopenic patients along with underlying mechanisms warrant further exploration.

Long-term outcomes of intestinal transplantation from donors aged under 1 year.

BACKGROUND: The aim of the study was to analyze the long-term outcomes of transplants utilizing ITx donors <1 year and to compare these results with older donors. METHODS: Between January 2007 and December 2019, the primary ITx donors in the Children's Hospital of Pittsburgh of UPMC were retrospectively reviewed. Short- and long-term outcomes of recipients receiving a deceased donor organ from donors <1 year were compared with those found in all other recipients. RESULTS: During the study period, there were 89 primary ITx donors, using 30 donors (33.7%) aged <1 year. The mean age of their recipients was 1.6 ± 0.7 (0.7-3.2) years. The 30 graft types were isolated intestine (n = 3, 10.0%), liver bowel (n = 20, 66.7%), and multivisceral (n = 7, 23.3%). Technical complications occurred in 12 (40.0%) recipients. Candidates transplanted with intestine allografts from donors <1 year of age had shorter wait times (p < .001), more liver-inclusive grafts (p < .001), and less donor-specific antibodies (DSA) (p = .014). During follow-up, the recipients had less graft loss (p = .018), and more remained alive with graft in place (p = .011). Among children transplanted with such donors, 3-year and graft survival rates were 86.7% and 82.9% compared to 62.8% and 49.9% in the cohort of donors >1 year (p = .032 and .011). CONCLUSIONS: Donor age <1 year was associated with improved graft survival. Optimal utilization of this population for toddler candidates would increase intestine availability, reduce time to transplantation, and potentially improve long-term outcome.

Liver simulated allocation model does not effectively predict organ offer decisions for pediatric liver transplant candidates.

The SRTR maintains the liver-simulated allocation model (LSAM), a tool for estimating the impact of changes to liver allocation policy. Integral to LSAM is a model that predicts the decision to accept or decline a liver for transplant. LSAM implicitly assumes these decisions are made identically for adult and pediatric liver transplant (LT) candidates, which has not been previously validated. We applied LSAM's decision-making models to SRTR offer data from 2013 to 2016 to determine its efficacy for adult (≥18) and pediatric (<18) LT candidates, and pediatric subpopulations-teenagers (≥12 to <18), children (≥2 to <12), and infants (<2)-using the area under the receiver operating characteristic (ROC) curve (AUC). For nonstatus 1A candidates, all pediatric subgroups had higher rates of offer acceptance than adults. For non-1A candidates, LSAM's model performed substantially worse for pediatric candidates than adults (AUC 0.815 vs. 0.922); model performance decreased with age (AUC 0.898, 0.806, 0.783 for teenagers, children, and infants, respectively). For status 1A candidates, LSAM also performed worse for pediatric than adult candidates (AUC 0.711 vs. 0.779), especially for infants (AUC 0.618). To ensure pediatric candidates are not unpredictably or negatively impacted by allocation policy changes, we must explicitly account for pediatric-specific decision making in LSAM.

Cost-Effectiveness of Primary Liver Transplantation Versus Hepatoportoenterostomy in the Management of Biliary Atresia in the United States.

Biliary atresia (BA) is the leading indication to perform a pediatric liver transplantation (LT). Timely hepatoportoenterostomy (HPE) attempts to interrupt the natural history and allow for enteric bile flow; however, most patients who are treated with HPE require LT by the age of 10 years. We determined the cost-effectiveness of foregoing HPE to perform primary LT (pLT) in children with BA compared with standard-of-care HPE management. A Markov model was developed to simulate BA treatment over 10 years. Costs were measured in 2018 US dollars and effectiveness in life-years (LYs). The primary outcome was incremental cost-effectiveness ratio (ICER) between treatments. Model parameters were derived from the literature. In the base model, we assumed similar LT outcomes after HPE and pLT. Sensitivity analyses on all model parameters were performed, including a scenario in which pLT led to 100% patient and graft survival after LT. Children undergoing HPE accumulated $316,692 in costs and 8.17 LYs per patient. Children undergoing pLT accumulated $458,059 in costs and 8.24 LYs per patient, costing $1,869,164 per LY gained compared with HPE. With parameter variation over plausible ranges, only post-HPE and post-LT costs reduced the ICER below a typical threshold of $100,000 per LY gained. On probabilistic sensitivity analysis, 93% of iterations favored HPE at that threshold. With 100% patient and graft survival after pLT, pLT cost $283,478 per LY gained. HPE is more economically favorable than pLT for BA. pLT is unfavorable even with no graft or patient loss. The ability to predict those patients who may experience high costs after HPE or low costs after LT may help identify those patients for whom pLT could be considered.

Approaches to Research Determination of Late Acute Cellular Rejection in Pediatric Liver Transplant Recipients.

A central pathology or site reading of biopsy slides is used in liver transplant clinical trials to determine rejection. We evaluated interrater reliability of readings of "rejection or not" using digitized slides from the Medication Adherence in Children who had a Liver Transplant (MALT) study. Four masked experienced pathologists read the digitized slides and then reread them after a study-specific histologic endpoint development program. Agreement was expressed throughout as a Kappa or Fleiss Kappa statistic (Ò¡). A Ò¡ > 0.6 was predefined as desirable. Readings were correlated with immunosuppressant adherence (the Medication Level Variability Index, [MLVI]), and maximal liver enzyme levels during the study period. Interrater agreement between site and central review in MALT, and between 4 pathologists later on, was low (Ò¡ = 0.44, Fleiss Ò¡ = 0.41, respectively). Following the endpoint development program, agreement improved and became acceptable (Ò¡ = 0.71). The final reading was better-aligned with maximal gamma-glutamyl transferase levels and MLVI as compared with the original central reading. We found substantial disagreement between experienced pathologists reading the same slides. A unique study-specific procedure improved interrater reliability to the point it was acceptable. Such a procedure may be indicated to increase reliability of histopathologic determinations in future research, and perhaps also clinically.

Metabolic Control and "Ideal" Outcomes in Liver Transplantation for Maple Syrup Urine Disease.

OBJECTIVES: To assess outcomes following liver transplantation for maple syrup urine disease by determining attainment and sustainability of metabolic control and apply an "ideal" outcome composite in long-term survivors. STUDY DESIGN: A single center, retrospective review collected clinical data including branched-chain amino acid (leucine, isoleucine, and valine) levels following liver transplant and determined achievement of an ideal long-term outcome profile of a first allograft stable on immunosuppression monotherapy, normal growth, and absence of common transplant-related sequelae. RESULTS: Of 77 patients meeting inclusion criteria identified, 23 were long-term (≥10-year) survivors and were additionally assessed for ideal outcome attainment. Patient and graft survival were 100% and 99%, respectively, and all patients were on an unrestricted protein intake diet. Although significant variation was noted in mean isoleucine (P < .01) and leucine (P < .05) levels postliver transplantation, no difference was seen in valine (P = .29) and overall clinical impact was likely negligible as metabolic stability was achieved and sustained beyond 3 years postliver transplantation and no metabolic crises were identified. Of 23 long-term survivors with available data, 9 (39%) achieved all composite metrics determined to define "ideal" outcomes in pediatric postliver transplantation populations. CONCLUSIONS: Liver transplant enables long-term metabolic stability for patients with maple syrup urine disease. A combination of experience and improvement in both pre- and postliver transplantation care has enabled excellent survival and minimal comorbidities following transplant.

Living Related Liver Transplantation for Metabolic Liver Diseases in Children.

ABSTRACT: Metabolic liver diseases (MLDs) are a heterogeneous group of inherited conditions for which liver transplantation can provide definitive treatment. The limited availability of deceased donor organs means some who could benefit from transplant do not have this option. Living related liver transplant (LrLT) using relatives as donors has emerged as one solution to this problem. This technique is established worldwide, especially in Asian countries, with shorter waiting times and patient and graft survival rates equivalent to deceased donor liver transplantation. However, living donors are underutilized for MLDs in many western countries, possibly due to the fear of limited efficacy using heterozygous donors. We have reviewed the published literature and shown that the use of heterozygous donors for liver transplantation is safe for the majority of MLDs with excellent metabolic correction. The use of LrLT should be encouraged to complement deceased donor liver transplantation (DDLT) for treatment of MLDs.

Domino transplantation for pediatric liver recipients: Obstacles, challenges, and successes.

BACKGROUND: Domino liver transplantation aims to address the need to increase the liver donor supply. In a domino liver transplant, the domino recipient receives the explanted liver from the recipient of a traditional liver transplant. The domino donor typically requires liver transplant to correct a metabolic disorder; the explanted liver thus has a single gene defect but otherwise normal structure and function. METHODS: In this review, we detail the history of domino liver transplantation, appropriate domino donor indications, the technical advances to the surgical approach, current outcomes, and future opportunities. RESULTS: Development of de novo disease in the domino recipient has relegated adult domino liver transplant to be considered a source of marginal donor livers. However, pediatric domino liver transplant has leveraged certain metabolic disorders, especially maple syrup urine disease, in which the liver enzyme deficiency can be compensated by the systemic presence of sufficient enzyme. Advances in the surgical aspects of assuring adequate length of vasculature have improved the safety of the procedure in both domino donors and recipients. CONCLUSIONS: Pediatric domino liver transplant utilizing domino donors with specific metabolic liver diseases should be considered a viable live donor option for children awaiting liver transplant.