Improved Outcomes for Liver Transplantation in Patients with Biliary Atresia Since Pediatric End-Stage Liver Disease Implementation: Analysis of the Society of Pediatric Liver Transplantation Registry

Major surgical conditions of childhood and their lifelong implications: comprehensive review

BACKGROUND

In recent decades, the survival of children with congenital anomalies and paediatric cancer has improved dramatically such that there has been a steady shift towards understanding their lifelong health outcomes. Paediatric surgeons will actively manage such conditions in childhood and adolescence, however, adult surgeons must later care for these 'grown-ups' in adulthood. This article aims to highlight some of those rare disorders encountered by paediatric surgeons requiring long-term follow-up, their management in childhood and their survivorship impact, in order that the adult specialist may be better equipped with skills and knowledge to manage these patients into adulthood.

METHODS

A comprehensive literature review was performed to identify relevant publications. Research studies, review articles and guidelines were sought, focusing on the paediatric management and long-term outcomes of surgical conditions of childhood. The article has been written for adult surgeon readership.

RESULTS

This article describes the aforementioned conditions, their management in childhood and their lifelong implications, including: oesophageal atresia, tracheo-oesophageal fistula, malrotation, short bowel syndrome, duodenal atresia, gastroschisis, exomphalos, choledochal malformations, biliary atresia, Hirschsprung disease, anorectal malformations, congenital diaphragmatic hernia, congenital lung lesions and paediatric cancer.

CONCLUSION

The increasing survivorship of children affected by surgical conditions will translate into a growing population of adults with lifelong conditions and specialist healthcare needs. The importance of transition from childhood to adulthood is becoming realized. It is hoped that this timely review will enthuse the readership to offer care for such vulnerable patients, and to collaborate with paediatric surgeons in providing successful and seamless transitional care.

Long-term outcomes of liver transplantation for biliary atresia and results of policy changes: over 20 years of follow-up experience

Objective

Biliary atresia (BA) patients develop chronic liver disease after the Kasai operation and are eventually indicated for liver transplantation (LT). The purposes of this study were to analyze long-term outcomes after LT and risk factors that affect complications to reduce graft failure.

Study design

Overall, 145 pediatric patients who underwent LT between June 1996 and June 2020 after a diagnosis of BA were included. We performed a retrospective analysis of medical records and evaluated patient and graft survival, cumulative incidence of complications, risk factors, and the results of policy changes.

Results

Patient and graft survival rates in over 20 years were 95.8% and 91.0%, respectively. Post-transplantation lymphoproliferative disease was frequently observed in the early period of immunosuppression within the first 1-2 years after LT. The incidence of cholangitis and rejection steadily increased over time. Weight-to-portal vein size was evaluated as a risk factor for cholangitis and bile duct strictures (OR = 12.82, p = 0.006 and OR = 16.54, p = 0.015, respectively). When evaluated using 2013 as a reference point, the split graft indication was expanded and the group that received LT after 2013 had a significantly lower survival over time compared with that of the group that received LT before 2013 (p = 0.006).

Conclusion

This study revealed time differences in prevalence of complications. The evaluation of weight-to-duct or vessel size is a more important factor in considering complications than the graft-to-recipient weight ratio. Survival outcomes may have been altered by a policy change that affects the donor type ratio in transplantation.

Combining living and deceased donation for pediatric first isolated liver transplantation: A win-win even in countries with high deceased donor donation rates

BACKGROUND

Split and living donor liver transplantations are both key surgical strategies for development of pediatric liver transplant programs. Often, however, teams tend to prioritize only one preferentially.

METHODS

In the context of a very active national split liver graft allocation program (Italy), retrospective study of 226 consecutive pediatric first isolated liver transplants performed by a single team using organs from both deceased and living donors. Clinical characterisitics and outcome were compared.

RESULTS

In the context of a steadily slowly decreasing split graft offer, living donation activity steadily increased. Deceased and living donation accounted for 52.6% and 47.4% of transplantations, respectively. Both strategies were equally used for transplanting patients up to 30 kg of weight, while deceased donors were predominantly used for older recipients. Technical variants represented 86% of all transplants, with 183 conisting of left lateral segment grafts (76 split liver grafts and 107 left grafts from living donors). Outcome of both surgical strategies was similar, with excellent outcomes at early, mid-, and long-term.

CONCLUSIONS

Splitting livers of deceased donors and using living donation were complementary and non-competitive strategies for developping pediatric liver transplant activity. Implementing both activities in parallell allowed to maintain stable the number of annual transplant in Italy and allowed to reach superior outcomes. This analysis provides evidence that living donation plays a role in Italy despite an existing very active "mandatory-split" national policy.

Biliary atresia and liver transplantation in the United States: A contemporary analysis

BACKGROUND

Biliary atresia (BA) remains the number one indication for paediatric liver transplantation (LT) worldwide but is an uncommon indication for older LT recipients. The impact of recent donor allocation changes, pervasive organ shortage and evolving LT practices on the BA LT population is unknown.

METHODS

We identified patients who underwent LT between January 2010 and December 2021 using the UNOS database. We compared clinical outcomes between patients with BA and those with non-BA cholestatic liver disease. Groups were stratified by age, <12 years (allocated via PELD system) and ≥12 years (allocated via MELD system). Waitlist outcomes were compared using competing-risk regression analysis, graft survival rates were compared using Kaplan-Meier time-to-event analysis and Cox proportional hazards modelling provided adjusted estimates.

RESULTS

There were 2754 BA LT waitlist additions and 2206 BA LTs (1937 <12 years [younger], 269 ≥12 years [older]). There were no differences in waitlist mortality between BA and non-BA cholestatic patients. Among BA LT recipients, there were 441 (20.0%) living-donor liver transplantations (LDLT) and 611 (27.7%) split deceased-donor LTs. Five-year graft survival was significantly higher among BA versus non-BA cholestatic patients in the older group (88.3% vs. 79.5%, p < .01) but not younger group (89.3% vs. 89.5%). Among BA LT recipients, improved graft outcomes were associated with LDLT (vs. split LT: HR: 2, 95% CI: 1.03-3.91) and higher transplant volume (volume >100 vs. <40 BA LTs: HR: 3.41, 95% CI: 1.87-6.2).

CONCLUSION

Liver transplant outcomes among BA patients are excellent, with LDLT and higher transplant centre volume associated with optimal graft outcomes.

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.

The impact of low recipient weight [≤ 7kg] on long-term outcomes in 1078 pediatric living donor liver transplantations

BACKGROUND

infants who require liver transplantation represent a treatment challenge because chronic liver disease at this early age affects the child's growth and development during a critical phase. The aim is to compare demographics, operative data, and long-term outcomes according to recipient weight at the time of LDLT.

METHODS

This retrospective study included primary LDLT analyzed in 2 groups: BW ≤ 7 kg (n = 322) and BW > 7 kg (n = 756). A historical comparison between periods was also investigated.

RESULTS

BW ≤ 7 kg had significantly lower height/age and weight/age z-scores, with median PELD score of 19. Transfusion rates were higher in the BW ≤ 7 kg group (30.9 ml/kg versus 15.5 ml/kg, P < 0.001). Higher frequencies of PV complications were seen in the BW ≤ 7 kg cohort. HAT and retransplantation rates were similar. Those with BW ≤ 7 kg required longer ICU and hospital stays. Patient and graft survival were similar. Patient survival in BW≤ 7 kg was significantly better in the most recent period.

CONCLUSION

Malnutrition and advanced liver disease were more frequent in BW ≤ 7 kg. Despite increased rates of PVT and longer hospital stay, patient and graft long-term survival were similar between groups.

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.

Primary vs. salvage liver transplantation for biliary atresia: A retrospective cohort study

INTRODUCTION

Kasai hepatoportoenterostomy is the standard of care for children with biliary atresia, but a majority of patients progress to end-stage liver disease and require a salvage liver transplant. Given the high failure rates of the hepatoportoenterostomy operation, some have advocated for primary liver transplantation as a superior treatment approach. The aim of this study was to compare outcomes of pediatric candidates with biliary atresia listed for primary vs. salvage liver transplantation.

METHODS

The SRTR/OPTN database was retrospectively reviewed for all children with biliary atresia listed for liver transplant between March 2002 and February 2021. Candidates were categorized as primary liver transplant if they had not undergone previous abdominal surgery prior to listing and salvage liver transplant if they had. Salvage transplants were further categorized as early failure if listed within the first year of life or late failure if listed at an older age.

RESULTS

3438 children with biliary atresia were listed for transplant during the study period, with 15% of them listed for a primary transplant, 17% for salvage transplant after early failure, and 67% after late failure. Recipients of salvage liver transplant with late failure had lower bilirubin levels and were less critically ill as demonstrated by MELD/PELD scores and hospitalization status. Correspondingly, these recipients had higher waiting list and graft survival, though this did not remain statistically significant after adjustment in multivariable models. There were no differences in waiting list, recipient, or graft survival with primary vs. salvage liver transplant after early failure.

CONCLUSION

Kasai hepatoportoenterostomy should remain the standard of care in biliary atresia as it may delay need for transplant beyond the first year of life in a subset of recipients and does not jeopardize subsequent transplant outcomes, even with early failure.

LEVELS OF EVIDENCE

Retrospective cohort study (Level III).

[Overview of Biliary Atresia]

Biliary atresia is a progressive, idiopathic, obliterative disease of the extrahepatic biliary tree that presents with biliary obstruction in the neonatal period. It is the most common indication for liver transplantation in children. If untreated, progressive liver cirrhosis leads to death by two years of age. Nowadays, more than 90% of biliary atresia patients survive into adulthood with the development of Kasai portoenterostomy and liver transplantation technology. Early diagnosis is critical since the success rate of the Kasai portoenterostomy decreases with time. This study comprehensively reviews the recent advances in the etiology, classification, prevalence, clinical manifestations, treatment, and prognosis of biliary atresia.

Reduced peroxisome proliferator-activated receptor-α and bile acid nuclear receptor NR1H4/FXR may affect the hepatic immune microenvironment of biliary atresia

Background

Biliary atresia (BA) is a childhood liver disease characterized by fibrous obstruction and obstruction of the extrahepatic biliary system and is one of the most common and serious biliary disorders in infants. Significant inflammation and fibrosis of the liver and biliary tract are the most prominent features, regardless of the initial damage to the BA. Abnormalities in innate or adaptive immunity have been found in human patients and mouse models of BA. We previously reported that children with BA had abnormal lipid metabolism, including free serum carnitine.

Objective

To study gene and protein expression levels of the hepatic peroxisome proliferator-activated receptor-α (PPARα) signaling pathway and farnesoid X receptor (FXR) in BA and BA fibrosis, and assess their clinical values.

Methods

Low expression of PPARα and NR1H4 (FXR) in BA were validated in the Gene Expression Omnibus database. Functional differences were determined by gene set enrichment analysis based on of PPARα and NR1H4 expression. BA patients from GSE46960 were divided into two clusters by using consensus clustering according to PPARα, NR1H4, and SMAD3 expression levels, and immunoinfiltration analysis was performed. Finally, 58 cases treated in our hospital were used for experimental verification. (IHC: 10 Biliary atresia, 10 choledochal cysts; PCR: 10 Biliary atresia, 14 choledochal cysts; WB: 10 Biliary atresia, 4 choledochal cysts).

Results

Bioinformatics analysis showed that the expression of PPARα, CYP7A1 and NR1H4 (FXR) in the biliary atresia group was significantly lower than in the control group. More BA-specific pathways, including TGFβ signaling pathway, P53 signaling pathway, PI3K-AKT-mTOR signaling pathway, etc., are enriched in BA patients with low PPARα and NR1H4 expression. In addition, low NR1H4 expression is abundant in inflammatory responses, IL6/STAT3 signaling pathways, early estrogen responses, IL2 STAT5 signaling pathways, and TGFβ signaling pathways. The TGFβ signaling pathway was significant in both groups. According to the expression of PPARα, NR1H4 and SMAD3, a key node in TGFβ pathway, BA patients were divided into two clusters using consensus clustering. In cluster 2, SMAD3 expression was high, and PPARα and NR1H4 expression were low. In contrast to cluster 1, immune cell infiltration was higher in cluster 2, which was confirmed by immunohistochemistry. The mRNA and protein levels of PPARα and NR1H4 in BA patients were lower than in the control group by immunohistochemistry, Western blot analysis and real-time PCR.

Conclusions

The downregulation of PPARα and NR1H4 (FXR) signaling pathway may be closely related to biliary atresia.

Biliary Atresia in Children: Update on Disease Mechanism, Therapies, and Patient Outcomes

Biliary atresia is a rare disease but remains the most common indication for pediatric liver transplantation as there are no effective medical therapies to slow progression after diagnosis. Variable contribution of genetic, immune, and environmental factors contributes to disease heterogeneity among patients with biliary atresia. Developing a deeper understanding of the disease mechanism will help to develop targeted medical therapies and improve patient outcomes.

Primary Liver Transplantation vs. Transplant after Kasai Portoenterostomy for Infants with Biliary Atresia

Introduction: Primary liver transplants (pLT) in patients with biliary atresia (BA) are infrequent, since most babies with BA undergo a prior Kasai portoenterostomy (KPE). This study compared transplant outcomes in children with BA with or without a prior KPE. We hypothesized that pLT have less morbidity and better outcomes compared to those done after a failed KPE. Methods: A retrospective review of patients with BA transplanted at our institution was performed. Patients were included if they received a pLT or if they were transplanted less than 2 years from KPE. Outcomes were compared between those groups. Comparisons were also made based on era (early: 1997−2008 vs. modern: 2009−2020). p < 0.05 was considered significant. Results: Patients who received a pLT were older at diagnosis (141.5 ± 46.0 vs. KPE 67.1 ± 25.5 days, p < 0.001). The time between diagnosis and listing for transplant was shorter in the pLT group (44.5 ± 44.7 vs. KPE 140.8 ± 102.8 days, p < 0.001). In the modern era, the calculated PELD score for the pLT was significantly higher (23 ± 8 vs. KPE 16 ± 8, p = 0.022). Two waitlist deaths occurred in the KPE group (none in pLT, p = 0.14). Both the duration of transplant surgery and transfusion requirements were similar in both groups. There was a significant improvement in graft survival in transplants after KPE between eras (early era 84.3% vs. modern era 97.8%, p = 0.025). The 1-year patient and graft survival after pLT was 100%. Conclusions: Patient and graft survival after pLT are comparable to transplants after a failed KPE but pLT avoids a prior intervention. There was no significant difference in pre- or peri-transplant morbidity between groups other than wait list mortality. A multicenter collaboration with more patients may help demonstrate the potential benefits of pLT in patients predicted to have early failure of KPE.

Organ-Specific Comorbidities Are Associated With Distinct Complications After Liver Transplantation for Biliary Atresia

Although transplant outcomes for biliary atresia (BA) have improved, there are few data to predict the risk of specific posttransplant complications. We therefore defined the impact of comorbidities in BA on posttransplant outcomes. Patients enrolled in the Society of Pediatric Liver Transplantation registry from 2011 to 2019 (n = 1034) were grouped by comorbidities of >1.0% incidence: any supplemental feeding, dialysis, other abdominal surgery (not Kasai portoenterostomy [KPE]), hepatopulmonary syndrome, and cardiac disease requiring intervention. Demographic and outcome data were compared using the Kruskal-Wallis, chi-square, and log-rank tests. Cox proportional hazards models and binary logistic regression were performed for modeling. Patients with BA with comorbidities comprised 77% (n = 799) of our cohort and had evidence of greater medical acuity, including higher calculated Pediatric End-Stage Liver Disease scores and hospitalizations in the intensive care unit before transplant (P < 0.001 for both) versus those without comorbidities. After transplant, patients with BA with comorbidities had more graft loss (P = 0.02), longer initial hospitalization and intubation (P < 0.001 for both), and increased rates of reoperation (P = 0.001) and culture-proven infection (P < 0.001) within 30 days after transplant. Only patients with BA with comorbidities on supplemental feed had increased rates of patient death (P = 0.02). Multivariate analysis identified lower z weight and higher creatinine as risk factors for graft and patient loss in patients with BA with comorbidities. Prior KPE was protective against culture-proven infection and vascular complications within 30 and 90 days, respectively. Patients with BA with comorbidities have evidence of higher medical acuity at transplant and reduced graft survival; however, they overall did not experience greater incidence of patient death. Our data provide organ-system-specific data to risk-stratify patients with BA and posttransplant outcomes.

Recipient-Specific Risk Factors Impairing Patient and Graft Outcome after Pediatric Liver Transplantation-Analysis of 858 Transplantations in 38 Years

(1) Background and Aim: Despite excellent long-term results in pediatric liver transplantation (pLTx), mortality and graft loss still are to be diminished. We aim to describe time-dependent changes and long-term outcome of a large single-center pLTx cohort and to identify independent recipient-related risk factors impairing patient and graft survival. (2) Methods: This is a retrospective single-center study analyzing all pediatric liver transplants from 1983–2020. Risk factors for mortality and graft loss were identified by univariable and multi-linear regression analysis. (3) Results: We analyzed 858 liver transplantations in 705 pediatric patients. Five-year patient/graft survival increased from 60.9%/48.0% (1983–1992) to 97.5%/86.5% (OR = 12.5; p < 0.0001/OR = 6.5; p < 0.0001) (2014–2020). Indications changed significantly over time, with a higher proportion of patients being transplanted for malignancies and metabolic disease and indications of PFIC and α1AT-deficiency declining. The era of transplantation (log7.378/9.657; p < 0.0001) and indication of acute liver failure (log = 1.944/2.667; HR = 2.015/1.772; p = 0.0114/0.002) impairs patient/graft survival significantly in the multivariate analysis. Furthermore, patient survival is worsened by re-transplantation (log = 1.755; HR = 1.744; p = 0.0176) and prolonged waiting times in high-urgency status (log = 2.588; HR = 1.073; p = 0.0026), whereas the indication of biliary atresia improved outcome (log = 1.502; HR = 0.575; p = 0.0315). Graft survival was additionally impaired by pre-existing portal vein thrombosis (log = 1.482; HR = 2.016; p = 0.0330). (4) Conclusions: Despite more complex indications, patient and graft survival after pLTx continue to improve.. Acute liver failure remains the indication with poorest outcome, and listing for high urgency liver transplantation should be considered carefully and early to keep waiting time on HU list short. Furthermore, pre-transplant portal vein thrombosis should be prevented whenever possible to improve graft survival.

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.

Standardization of post-operative antimicrobials reduced exposure while maintaining good outcomes in pediatric liver transplant recipients

Infections following orthotopic liver transplant (OLT) result in significant morbidity and mortality, warranting careful consideration of risks associated with antibiotic overuse and benefits of infection prevention. In the absence of specific guidelines for antimicrobial prophylaxis in pediatric OLT, we developed a standardized approach to post-operative (post-op) antimicrobial therapy including 48 hours of antibiotics, no vancomycin for post-op fever within the first 48 hours, and caspofungin only for certain situations. The goal was to reduce antimicrobial utilization and adverse outcomes associated with longer duration of and broader treatment while maintaining good outcomes. The impact of this standardization on antimicrobial utilization and clinical outcomes at the largest pediatric liver transplant center in the United States is described. All individuals receiving an OLT from 1/1/17-9/30/17 (N = 38) and 3/14/18-12/13/18 (N = 27) were included in the pre-intervention (PreI) and post-intervention (PostI) groups, respectively. The intervention resulted in a significant reduction in individuals receiving post-op broad-spectrum gram-negative antibiotics for >48 hours (76% PreI vs 44% PostI OLT recipients, P = .01) and post-op vancomycin use (50% PreI, vs 7.4% PostI, P < .001). There were no statistically significant differences between groups for post-op fever, positive pre-/post-operative cultures, receipt of massive transfusion, or hospital length of stay. In conclusion, following the implementation of a standardized approach to post-op prophylaxis, antimicrobial exposure was significantly reduced without affecting OLT recipient outcomes.