Liver Transplantation in Children

Expert consensus on the diagnosis and treatment of end-stage liver disease complicated by infections

End-stage liver disease (ESLD) is a life-threatening clinical syndrome and when complicated with infection the mortality is markedly increased. In patients with ESLD, bacterial or fungal infection can induce or aggravate the occurrence or progression of liver decompensation. Consequently, infections are among the most common complications of disease deterioration. There is an overwhelming need for standardized protocols for early diagnosis and appropriate management for patients with ESLD complicated by infections. Asia Pacific region has the largest number of ESLD patients, due to hepatitis B and the growing population of alcohol and NAFLD. Concomitant infections not only add to organ failure and high mortality but also to financial and healthcare burdens. This consensus document assembled up-to-date knowledge and experience from colleagues across the Asia-Pacific region, providing data on the principles as well as evidence-based current working protocols and practices for the diagnosis and treatment of patients with ESLD complicated by infections.

Management of pediatric liver failure with therapeutic plasma exchange and continuous renal replacement therapy: A retrospective observational study

Liver failure represents a critical medical condition, marked by the rapid decline of hepatic functions. Emerging therapies, notably therapeutic plasma exchange (TPE) and continuous venovenous hemodiafiltration (CVVHDF), have demonstrated potential in mitigating these conditions through their roles in detoxification and hepatic support. The utility of these treatments, whether applied individually or in tandem, constitutes a significant area of research concerning the management of liver failure in pediatric patients. This study aims to evaluate the role and efficacy of TPE or TPE combined with CVVHDF in the treatment of liver failure among children. This retrospective study was conducted in a LTICU by reviewing the medical history of pediatric patients aged 1 month to 18 years. Patients were admitted between January 1, 2021 and December 1, 2023 due to acute liver failure or acute-chronic liver failure. The study evaluated those who received TPE or continuous renal replacement therapy combined with TPE. In statistical analyses, a P-value of <.05 was considered statistically significant. The study involved 24 patients with liver failure, comprising 13 males and 11 females. Sixteen patients (66.6%) received only TPE, while 8 patients (33.4%) were treated with TPE and CVVHDF. For patients treated only with TPE, the median INR reduced from 3.1 to 1.26, alanine aminotransferase from 1255 to 148, and aspartate aminotransferase from 2189 to 62. Similar significant reductions were observed in the TPE and CVVHDF group: INR from 3.9 to 1.26, alanine aminotransferase from 1749 to 1148, and aspartate aminotransferase from 1489 to 62. These changes were statistically significant with P-values of .01 for each parameter in both groups. Overall, 14 patients survived without requiring a liver transplant, while 4 patients underwent liver transplantation. Our study on pediatric liver failure treatment shows that both standalone TPE and its combination with CVVHDF are effective, especially as a bridge to transplantation. With 58% transplant-free survival, these therapies demonstrate significant clinical improvements. Future multicentric studies are needed for broader validation of these findings in liver failure management.

Evaluation of liver transplantation services in Kazakhstan from 2012 to 2023

There is a scarcity of publications evaluating the performance of the national liver transplantation (LTx) program in Kazakhstan. Spanning from 2012 to 2023, it delves into historical trends in LTx surgeries, liver transplant centers, and the national cohort of patients awaiting LTx. Survival analysis for those awaiting LTx, using life tables and Kaplan-Meier, is complemented by time series analysis projecting developments until 2030. The overall per million population (pmp) LTx rate varied from 0.35 to 3.77, predominantly favoring living donor LTx. Liver transplant center rates ranged from 0.06 to 0.40. Of 474 LTx patients, 364 on the waiting list did not receive transplantation. The 30-day and 1-year survival rates on the waiting list were 87.0% and 68.0%, respectively. Viral hepatitis and cirrhosis prevalence steadily rose from 2015 to 2023, with projections indicating a persistent trend until 2030. Absent targeted interventions, stable pmp rates of LTx and liver transplant centers may exacerbate the backlog of unoperated patients. This study sheds light on critical aspects of the LTx landscape in Kazakhstan, emphasizing the urgency of strategic interventions to alleviate the burden on patients awaiting 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.

The Ratio of Intraoperative Red Blood Cell Transfusion to Blood Loss Associated with Early Postoperative Complications in Pediatric Liver Transplantation Patients

Introduction

Liver transplantation (LT) is an operation purposed to save the lives of children with acute or chronic liver diseases, hepatic tumors, and some genetic and metabolic diseases. However, patients who underwent LT have a significant risk of intraoperative blood loss and red blood cell (RBC) transfusion, especially in pediatric patients.

Methods

In this study, 569 pediatric patients (<18 years old) who underwent LT at a tertiary university hospital between 2013 and 2020 were included. Multiple logistic regression was used to analyze the association between the ratio of intraoperative RBC transfusion to blood loss (IRTBL) and the complications after LT in pediatric patients. IRTBL was divided into quartiles in the adjusted model. Odds ratios, 95% confidence intervals, and p values for trends were calculated. Restricted cubic spline (RCS) regression was used to evaluate the nonlinear association between IRTBL and complications.

Results

Compared with the lowest level and the highest level of IRTBL, Q2 and Q3 quartiles of IRTBL showed significantly positive association with early complications. A significantly nonlinear association was observed between the IRTBL and early complications in the RCS model with the multiple adjustments of potential covariates (P overall<0.01, P nonlinear<0.01). However, no significant association was observed between late complications and IRTBL.

Conclusion

In this study, we found there was a nonlinear relationship between the ratio of IRTBL and early postoperative complications in pediatric LT patients, which provides a theoretical basis for RBC transfusion in pediatric LT patients.

Live-attenuated vaccination for measles, mumps, and rubella in pediatric liver transplantation

BACKGROUND

Infections are a serious short- and long-term problem after pediatric organ transplantation. In immunocompromised patients, they can lead to transplant rejection or a severe course with a sometimes fatal outcome. Vaccination is an appropriate means of reducing morbidity and mortality caused by vaccine-preventable diseases. Unfortunately, due to the disease or its course, it is not always possible to establish adequate vaccine protection against live-attenuated viral vaccines (LAVVs) prior to transplantation. LAVVs such as measles, mumps, and rubella (MMR) are still contraindicated in solid organ transplant recipients receiving immunosuppressive therapy (IST), thus creating a dilemma.

AIM

This review discusses whether, when, and how live-attenuated MMR vaccines can be administered effectively and safely to pediatric liver transplant recipients based on the available data.

MATERIAL AND METHODS

We searched PubMed for literature on live-attenuated MMR vaccination in pediatric liver transplantation (LT).

RESULTS

Nine prospective observational studies and three retrospective case series were identified in which at least 833 doses of measles vaccine were administered to 716 liver transplant children receiving IST. In these selected patients, MMR vaccination was well tolerated and no serious adverse reactions to the vaccine were observed. In addition, an immune response to the vaccine was demonstrated in patients receiving IST.

CONCLUSION

Due to inadequate vaccine protection in this high-risk group, maximum efforts must be made to ensure full immunization. MMR vaccination could also be considered for unprotected patients after LT receiving IST following an individual risk assessment, as severe harm from live vaccines after liver transplantation has been reported only very rarely. To this end, it is important to establish standardized and simple criteria for the selection of suitable patients and the administration of the MMR vaccine to ensure safe use.

Implementing living-donor pediatric liver transplantation in Southern Vietnam: 15-year results and perspectives

BACKGROUND

ND2 in Ho Chi Minh City is currently the only public center that performs PLT in Southern Vietnam. In 2005, the first PLT was successfully performed, with support from Belgian experts. This study reviews the implementation of PLT at our center and evaluates the results and challenges.

METHODS

Implementation of PLT at ND2 required medico-surgical team building and extensive improvement of hospital facilities. Records of 13 transplant recipients from 2005 to 2020 were studied retrospectively. Short- and long-term complications, as well as the survival rates, were reported.

RESULTS

The mean follow-up time was 8.3 ± 5.7 years. Surgical complications included one case of hepatic artery thrombosis that was successfully repaired, one case of colon perforation resulting in death from sepsis, and two cases of bile leak that were drained surgically. PTLD was observed in five patients, of whom three died. There were no cases of retransplantation. The 1-year, 5-year, and 10-year patient survival rates were 84.6%, 69.2%, and 69.2%, respectively. There were no cases of complication or death among the donors.

CONCLUSION

Living-donor PLT was developed at ND2 for providing a life-saving treatment to children with end-stage liver disease. Early surgical complication rate was low, and the patient survival rate was satisfactory at 1 year. Long-term survival decreased considerably due to PTLD. Future challenges include surgical autonomy and improvement of long-term medical follow-up with a particular emphasis on prevention and management of Epstein-Barr virus-related disease.

Prospective comparison of an 18-gauge versus 16-gauge needle for percutaneous liver core-needle biopsy in children

PURPOSE

The objective of this study was to analyzed the impact of needle gauge (G) on the adequacy of specimens and hemorrhagic complications in pediatric patients undergoing ultrasound (US)-guided transplanted liver biopsies.

METHODS

The study included 300 consecutive biopsies performed in 282 pediatric patients (mean age 6.75 ± 3.82 years, range 0.84-17.90) between December 2020 and April 2022. All pediatric patients that referred to our institution for US-guided core-needle liver biopsy (CNLB) were randomized to undergo 16-G or 18-G CNLB. Hemorrhagic complications were qualitatively evaluated. The number of complete portal tracts (CPTs) per specimen was counted and specimen adequacy was assessed based on the American Association for the Study of Liver Diseases guidelines.

RESULTS

The incidence of bleeding was 7.00% (n = 21) and adequate specimens for accurate pathological diagnosis were obtained from 98.33% (n = 295) of patients. There was no significant difference in the incidence or amount of bleeding between the 16-G and 18-G groups (11 vs 10, p = 0.821; 35.0 mL vs 31.3 mL, p = 0.705). Although biopsies obtained using a 16-G needle contained more complete portal tracts than those obtained using an 18-G needle (20.0 vs 18.0, p = 0.029), there was no significant difference in specimen inadequacy according to needle gauge (2 vs 3, p = 1.000).

CONCLUSIONS

Biopsy with a 16-G needle was associated with a greater number of CPTs but did not increase the adequate specimen rate. There was no significant difference in the complication rate between 16-G biopsy and 18-G biopsy.

Outcome of pediatric living donor liver transplant: Experience from Pakistan; a resource limited setting

INTRODUCTION

Liver transplantation (LT) has emerged as a lifesaving modality for many liver diseases in children. Pediatric LT is an established treatment in the Western world but is relatively a new procedure in resource-limited countries like Pakistan. The study aims to highlight the outcomes and survival of pediatric recipients from the first pediatric liver transplant center in Pakistan.

METHOD

A retrospective analysis of pediatric LT was done from 2012 to 2019. The study was conducted in the Hepatobiliary and liver transplant department of Shifa International Hospital (SIH), Islamabad. A detailed analysis for indications for pediatric LT, survival, and complications was done.

RESULTS

Forty-five patients under 18 years of age underwent Living donor liver transplant (LDLT) in SIH. Median age was 9 years and M:F of 2:1. Cryptogenic liver disease followed by Wilson disease were the two most common indications of LT. The majority of patients had chronic liver disease 34 (75%) while 11 (24%) had acute liver failure. The right lobe graft was the most common type of graft 19 (42.2%). Thirty days, 1-year, 3-year, and 5-year survival was 77.8%, 75.6%, 73.3%, and 60.6% respectively. Mortality was highest in patients with biliary atresia 4 (33%). Causes of death included pulmonary embolism, sepsis, surgical complications, and acute kidney injury. Mean survival was 88.850 months (±7.899) (CI 73.369-104.331).

CONCLUSION

Pediatric LDLT has offered disease-free survival for patients. Survival can improve further with nutritional rehabilitation and anticipation and management of post-operative complications.

Feasibility of steroid-free tacrolimus-basiliximab immunosuppression in pediatric liver transplantation and predictors for steroid requirement

Avoidance of steroids in pediatric liver transplantation may reduce toxicity and morbidity. The aim of this study was to analyze the feasibility of a steroid-free tacrolimus-basiliximab immunosuppression scheme, the risk factors associated with steroid requirement, and safety parameters. Patients who underwent liver transplantation for biliary atresia between 2011 and 2019 were included and followed for 6 months after transplantation. Immunosuppression consisted of tacrolimus-based treatment with basiliximab induction. Steroid-free survival was estimated, and risk factors for steroid requirement were evaluated using multivariate Cox regression analysis. A total of 76 patients were included, of whom 42 (55.3%) required steroids (>14 d) due to biopsy-proven acute rejection (47.6%, n = 20), instability in liver function tests (35.7%, n = 15), tacrolimus-related adverse drug reactions (14.3%, n = 6), or other reasons (bronchospasm episode, n = 1). Steroid-free survival was 45.9% (95% CI, 35.9-58.8). Independent factors associated with steroid requirement included tortuosity in tacrolimus trough levels (≥1.76 vs. <1.76: HR 5.8, 95% CI, 2.6-12.7; p < 0.001) and mean tacrolimus trough levels (≥ 6.4 ng/mL vs. < 6.4 ng/mL: HR 0.4, 95% CI, 0.2-0.7; p = 0.002). The rate of bacterial and viral infections was comparable between patients with and without steroids, although in the former group, cytomegalovirus infection developed earlier ( p = 0.03). Patients receiving steroids had higher total cholesterol, LDL, and HDL levels ( p < 0.05) during follow-up, but no changes in the height Z-score were observed 1 year after transplantation. Basiliximab induction in combination with tacrolimus-based treatment avoided steroid requirements in 45% of the patients. Tacrolimus variability and trough levels below 6.4 ng/mL independently increased the risk of steroid requirement. Further efforts should be focused on personalizing immunosuppressive treatment.

Establishment of Biliary Atresia Prognostic Classification System via Survival-Based Forward Clustering - A New Biliary Atresia Classification

OBJECTIVES

To develop a machine learning algorithm with prognosis data to identify different clinical phenotypes of biliary atresia (BA) and provide instructions for choosing treatment schemes.

METHODS

Six hundred thirty-nine cases of type III BA were retrospectively collected from the Children's Hospital of Fudan University from Jan 1st, 2017 to Dec 1st, 2019 as a training dataset, and a survival-based forward clustering method, which can also be used to predict the subtype of a new patient was developed to identify BA subtypes.

RESULTS

A total of 2 clusters were identified (cluster 1 = 324 and cluster 2 = 315), where cluster 2 had a lower 2 y native liver survival post-Kasai rate. The infant patients in cluster 2 have higher weight, liver, and spleen volume, wider portal vein width, and older operative age; worse coagulation and liver function results; higher grade of liver fibrosis and detection rate of hepatic portal fibrous mass, and higher recent infection detection rate of herpes simplex virus type I. With the proposed prognostic classification system, the authors predicted the subtypes of the 187 cases of type III BA in a testing dataset collected from the whole year of 2020. The p-value computed from the log-rank testing for the Kaplan-Meier survival curves of the predicted two testing groups was 0.0113.

CONCLUSIONS

This classification system would be a convenient tool to choose appropriate treatment and accelerate the choice-making between clinicians and infant patients.

Pure laparoscopic versus open left lateral hepatectomy in pediatric living donor liver transplantation: a review and meta-analysis

PURPOSE

The meta-analysis was conducted to evaluate the safety and feasibility of pure laparoscopic left lateral hepatectomy in comparison with open approach for pediatric living donor liver transplantation (LDLT).

METHODS

A systemic literature survey was performed by searching the PubMed, EMBASE and Cochrane Library databases for articles that compared pure laparoscopic left lateral living donor hepatectomy (LLDH) and open left lateral living donor hepatectomy (OLDH) by November 2021. Meta-analysis was performed to assess donors' and recipients' perioperative outcomes using RevMan 5.3 software.

RESULTS

A total of five studies involving 432 patients were included in the analysis. The results demonstrated that LLDH group had significantly less blood loss (WMD = -99.28 ml, 95%CI -152.68 to -45.88, p = 0.0003) and shorter length of hospital stay (WMD = -2.71d, 95%CI -3.78 to -1.64, p < 0.00001) compared with OLDH group. A reduced donor overall postoperative complication rate was observed in the LLDH group (OR = 0.29, 95%CI 0.13-0.64, p = 0.002). In the subgroup analysis, donor bile leakage, wound infection and pulmonary complications were similar between two groups (bile leakage: OR = 1.31, 95%CI 0.43-4.02, p = 0.63; wound infection: OR = 0.38, 95%CI 0.10-1.41, p = 0.15; pulmonary complications: OR = 0.24, 95%CI 0.04-1.41, p = 0.11). For recipients, there were no significant difference in perioperative outcomes between the LLDH and OLDH group, including mortality, overall complications, hepatic artery thrombosis, portal vein and biliary complications.

CONCLUSION

LLDH is a safe and effective alternative to OLDH for pediatric LDLT, reducing invasiveness and benefiting postoperative recovery. Future large-scale multi-center studies are expected to confirm the advantages of LLDH in pediatric LDLT.

CLINICAL, LABORATORIAL AND EVOLUTIONARY ASPECTS OF PEDIATRIC PATIENTS WITH LIVER DISEASE DUE TO ALPHA 1-ANTITRYPSIN DEFICIENCY

BACKGROUND

Alpha 1-antitrypsin deficiency (AATD) is a hereditary codominant autosomal disease. This liver disease ranges from asymptomatic cases to terminal illness, which makes early recognition and diagnosis challenging. It is the main cause of pediatric liver transplantation after biliary atresia.

OBJECTIVE

To describe the clinical characteristics, as well as those of histologic and laboratory tests, phenotypic and/or genetic evaluation and evolution of a cohort of pediatric patients with AATD.

METHODS

This is a retrospective observational study of 39 patients with confirmed or probable AATD (without phenotyping or genotyping, but with suggestive clinical features, low serum alpha 1-antitrypsin (AAT) level and liver biopsy with PAS granules, resistant diastasis). Clinical, laboratory and histological varia-bles, presence of portal hypertension (PH) and survival with native liver have been analyzed.

RESULTS

A total of 66.7% of 39 patients were male (26/39). The initial manifestation was cholestatic jaundice in 79.5% (31/39). Liver transplantation was performed in 28.2% (11/39) of patients. Diagnosis occurred at an average of 3.1 years old and liver transplantation at 4.1 years of age. 89.2% (25/28) of the patients with confirmed AATD were PI*ZZ or ZZ. The average AAT value on admission for PI*ZZ or ZZ patients was 41.6 mg/dL. All transplanted patients with phenotyping or genotyping were PI*ZZ (or ZZ). Those who were jaundiced on admission were earlier referred to the specialized service and had higher levels of GGT and platelets on admission. There was no significant difference in the survival curve when comparing cholestatic jaundiced to non-cholestatic jaundiced patients on admission. Comparing patients who did or did not progress to PH, higher levels of AST and APRI score at diagnosis (P=0.011 and P=0.026, respectively) were observed and in the survival curves patients with PH showed impairment, with 20.2% survival with native liver in 15 years.

CONCLUSION

Jaundice is an important clinical sign that motivates referral to a specialist, but it does not seem to compromise survival with native liver. Patients progressing to PH had higher AST, APRi score on admission and significantly impaired survival with native liver. It is important to pay attention to these signs in the follow-up of patients with AATD.

Cost-effectiveness analysis of liver transplantation in biliary atresia according to the severity of end-stage liver disease

BACKGROUND

Timing for liver transplantation (LT) in biliary atresia (BA) children with end-stage liver disease (ESLD) is associated with all-cause mortality. The cut-off value of pediatric end-stage liver disease (PELD) score for LT consideration varies across institutions. We aimed to determine the cost-effectiveness of LT to prevent death among BA children registered on the waiting list with different severities of ESLD.

METHODS

Subjects were BA children aged < 12 years at a transplant center between 2010 and 2021. A decision tree was developed for cost-effectiveness analysis from a hospital perspective to compare all-cause death between patients initially registered with a low PELD score (< 15) and a high PELD score (≥ 15). Each patient's direct medical cost was retrieved from the beginning of registration until 5 years after LT, adjusted with an inflation rate to 2022 Thai Baht (THB).

RESULTS

Among 176 children, 138 (78.4%) were initially registered with the high PELD score. The cost and mortality rate of the low PELD score group (THB1,413,424 or USD41,904 per patient and 31.6% mortality) were less than the high PELD score group (THB1,781,180 or USD52,807 per patient and 47.9% mortality), demonstrating the incremental cost-effectiveness ratio (ICER) of THB2,259,717 or USD66,994 per death prevented. The cost of early post-operative admission had the highest effect on the ICER. Considering the break-even analysis, cost among children initially registered at the low PELD score was also less expensive over time.

CONCLUSIONS

Registration for LT at PELD score < 15 was more cost-effective to prevent death among BA children with ESLD.

The Factors Affecting Mortality After Pediatric Liver Transplantation and Long-Term Survival Outcomes: A Single Center Experience

BACKGROUND

Liver transplantation (LT) is a treatment modality in the pediatric population for several diseases like biliary atresia, metabolic liver disease, hepatoblastoma, and so on. According to the Organ Procurement and Transplantation Network, 5-year survival was reported as 85.4% to 93.5% by age after pediatric liver transplantation (PLT). This study aimed to evaluate our single-center experience of PLT by analyzing long-term results, comparing the outcomes with the literature, and identifying predictors of patient survival.

METHODS

The data of 40 patients who underwent LT at <18 years of age between June 2015 and June 2021 were studied retrospectively. Recipient characteristics such as age, sex, etiology of liver disease follow-up time, postoperative vascular and biliary complications, and donor characteristics were evaluated.

RESULTS

There were 20 (50%) girls and 20 (50%) boys, and the median age was 42 (IQR = 9-117) months. The most common indications of LT were biliary disorders (45%). A whole liver graft was used in 7 (17%), a right lobe graft in 9 (23%), a left lobe graft in 4 (10%), and a left lateral lobe graft in 20 (50%) of the recipients. The 1-, 3-, 5-, and 7-year survival rates were 85%, 82.1%, 82.1%, and 82.1%, respectively. The multivariate survival analysis revealed that the pediatric end-stage liver disease score, hepatic artery thrombosis, and portal vein thrombosis are associated with overall mortality.

CONCLUSION

In conclusion, our long-term survival is similar to the literature, with satisfactory results. However, reducing the vascular complication rates can provide superior results on PLT.

A European International Multicentre Survey on the Current Practice of Perioperative Antibiotic Prophylaxis for Paediatric Liver Transplantations

(1) Background: Postoperative infections are major contributors of morbidity and mortality after paediatric liver transplantation (pLTX). Evidence and recommendations regarding the most effective antimicrobial strategy are lacking. (2) Results: Of 39 pLTX centres, 20 responded. Aminopenicillins plus ß-lactamase inhibitors were used by six (30%) and third generation cephalosporins by three (15%), with the remaining centres reporting heterogenous regimens. Broad-spectrum regimens were the standard in 10 (50%) of centres and less frequent in the 16 (80%) centres with an infectious disease specialist. The duration ranged mainly between 24-48 h and 3-5 days in the absence and 3-5 days or 6-10 days in the presence of risk factors. Strategies regarding antifungal, antiviral, adjunctive antimicrobial, and surveillance strategies varied widely. (3) Methods: This international multicentre survey endorsed by the European Liver Transplant Registry queried all European pLTX centres from the registry on their current practice of perioperative antibiotic prophylaxis and antimicrobial strategies via an online questionnaire. (4) Conclusions: This survey found great heterogeneity regarding all aspects of postoperative antimicrobial treatment, surveillance, and prevention of infections in European pLTX centres. Evidence-based recommendations are urgently needed to optimise antimicrobial strategies and reduce the spectrum and duration of antimicrobial exposure.

Late airway complications following pediatric liver transplantation: A case series

BACKGROUND

Late airway complications, as consequence of immunosuppression following pediatric liver transplantation are uncommonly reported.

METHODS

In this retrospective case series, we describe two young children presenting with symptoms of airway obstruction, secondary to differing pathologies in the supraglottic airway, as a result of immunosuppression following liver transplantation.

RESULTS

Case 1, a 2-year-old girl who presented with stridor 12-months following liver transplantation, was found to have a proliferative soft tissue mass involving the supraglottic larynx. Biopsies were consistent with infiltrative eosinophilic laryngitis and associated eosinophilic esophagitis. Case 2, a 12-month-old female who presented with stridor 5-months following liver transplantation, was found to have an exophytic soft tissue mass involving the supraglottis and hypopharynx. Biopsies revealed polymorphic Epstein-Barr virus (EBV) driven post-transplant lymphoproliferative disease (PTLD). Case 1 was managed with local resection and high dose oral corticosteroids. Case 2 responded to debulking of the necrotic supraglottic mass, reduction of immunosuppression and rituximab.

CONCLUSION

A high index of suspicion needs to be maintained for complications of immunosuppression for appropriate diagnosis of airway presentations following pediatric liver transplantation. Further research is necessary to improve early detection and consolidate management strategies for these airway lesions.

Advances in metformin for the treatment of non-alcoholic fatty liver disease in children

INTRODUCTION

The increased economic and social burdens for NAFLD worldwide make treating such a disease a significant public health issue. Metformin, a kind of insulin sensitizer generally used to treat type 2 diabetes, has been recently found to have efficacy on children's NAFLD in various areas such as glucolipid metabolism, intestinal bacterial metabolism, oxidative stress, and anti-inflammatory response. This article aims to provide an overview of the possible mechanisms of NAFLD in children and the potential therapeutic application of metformin.

AREAS COVERED

The Cochrane Library, PubMed, Scopus, and EMBASE database was systematically searched on 12 April 2022, using the keywords metformin; non-alcoholic fatty liver disease; and children to identify similar studies. An additional search for recently published research was performed in June 2020.

EXPERT OPINION

Although metformin has been proved to have an excellent therapeutic effect on children's NAFLD; we can still explore its potential impacts and mechanisms from different angles, such as combined medication. At the same time, we should also pay attention to its side effects.

Living Donor Liver Transplantation vs. Split Liver Transplantation Using Left Lateral Segment Grafts in Pediatric Recipients: An Analysis of the UNOS Database

Split and LDLT in pediatric patients have the potential to decrease wait times and waitlist mortality. Using UNOS-STAR data, we compared outcomes of pediatric patients undergoing LDLT and SLT using LLS grafts. The baseline characteristics and post-operative outcomes were compared between groups. Actuarial graft and patient survival were analyzed with Kaplan-Meier curves. Between 2010 and 2019, 911 pediatric LT were included in the analysis (LD graft group, n = 508, split graft group, n = 403). LD graft recipients spent more time on the waitlist vs. the split graft group (60 (22–138) days vs. 46 (16–108) days; p = 0.007). LD recipients had a lower rate of graft failure, found in 9.8% of patients compared with 14.6% in the split graft group (p = 0.02). HAT was the most common graft failure cause, with similar rates. Graft and patient survival at 1-, 3-, and 5-years was comparable between LDLT and SLT. In subgroup analyses, patients with biliary atresia, those ≤10 kg or ≤10 years old receiving an LD graft showed improved graft survival. In conclusion, LDLT is associated with a lower rate of graft failure in pediatric patients. The use of LLS regardless of the type of donor is a safe way to facilitate access to transplantation to pediatric patients with acceptable short and long-term outcomes.

Not only a small liver - The pathologist's perspective in the pediatric liver transplant setting

Pediatric liver transplantation represents a safe and long-lasting treatment option for various disease types, requiring the pathologist’s input. Indeed, an accurate and timely diagnosis is crucial in reporting and grading native liver diseases, evaluating donor liver eligibility and identifying signs of organ injury in the post-transplant follow-up. However, as the procedure is more frequently and widely performed, deceptive and unexplored histopathologic features have emerged with relevant consequences on patient management, particularly when dealing with long-term treatment and weaning of immunosuppression.

In this complex and challenging scenario, this review aims to depict the most relevant histopathologic conditions which could be encountered in pediatric liver transplantation. We will tackle the conditions representing the main indications for transplantation in childhood as well as the complications burdening the post-transplant phases, either immunologically (i.e., rejection) or non-immunologically mediated. Lastly, we hope to provide concise, yet significant, suggestions related to innovative pathology techniques in pediatric liver transplantation.

Contrast-enhanced ultrasound of transplant organs - liver and kidney - in children

Ultrasound (US) is the first-line imaging tool for evaluating liver and kidney transplants during and after the surgical procedures. In most patients after organ transplantation, gray-scale US coupled with color/power and spectral Doppler techniques is used to evaluate the transplant organs, assess the patency of vascular structures, and identify potential complications. In technically difficult or inconclusive cases, however, contrast-enhanced ultrasound (CEUS) can provide prompt and accurate diagnostic information that is essential for management decisions. CEUS is indicated to evaluate for vascular complications including vascular stenosis or thrombosis, active bleeding, pseudoaneurysms and arteriovenous fistulas. Parenchymal indications for CEUS include evaluation for perfusion defects and focal inflammatory and non-inflammatory lesions. When transplant rejection is suspected, CEUS can assist with prompt intervention by excluding potential underlying causes for organ dysfunction. Intracavitary CEUS applications can evaluate the biliary tract of a liver transplant (e.g., for biliary strictures, bile leak or intraductal stones) or the urinary tract of a renal transplant (e.g., for urinary obstruction, urine leak or vesicoureteral reflux) as well as the position and patency of hepatic, biliary and renal drains and catheters. The aim of this review is to present current experience regarding the use of CEUS to evaluate liver and renal transplants, focusing on the examination technique and interpretation of the main imaging findings, predominantly those related to vascular complications.

Wilson Disease in Children; Chelation Therapy or Liver Transplantation? A 10-Year Experience from Pakistan

Background

Wilson disease (WD) is a rare genetic disorder with vast clinical presentations and a higher incidence in areas where consanguinity is common. Most patients can be treated with oral chelation, but some require advanced surgical intervention, like liver transplantation (LT). This study aims to review outcomes of WD patients presenting to a tertiary care center over a period of 10 years.

Material/Methods

This retrospective analysis was conducted at Shifa International Hospital, Islamabad, Pakistan. Patients <18 years who were diagnosed with WD per ESPAGHAN guidelines from 2010 to 2020 were included. Presentation, diagnosis, treatment, and LT and its complications were recorded. Follow-ups were recorded, and patients were contacted by phone in cases of interrupted follow-up. Frequencies and percentages of variables were calculated.

Results

A total of 48 patients with WD were identified. Symptomatic disease was seen in 45 patients, with 3 diagnosed on screening. The hepatic form was common (62.2%). Mean age at diagnosis was 9.74 (range 5–17) years, 28 (58.3%) were male, while 17 (35.4%) were female. Urinary copper was increased in all patients (645.82±528.40). Oral treatment with penicillamine was given to 34 (75.5%) patients; 4 (8.9%) died while on oral treatment. Living donor LT was performed in 11 (22.9%) patients, who had a mean King’s Wilson index of 11 (range, 6–14). Currently, all LT patients are alive, with maximum graft survival of 7 years.

Conclusions

LT offers a promising treatment with good outcomes in pediatric WD. However, timely diagnosis and management with oral chelation therapy can prolong survival without LT.

Mental Health and Well-Being of Solid Organ Transplant Donors. The Forgotten Sacrifices

In light of a global organ shortage, living donor transplantation has become increasingly relevant as an alternative to deceased donor transplantation. While current research has revolved around the medical aspects of transplantation, there remains a paucity of literature regarding the quality of life (QOL) of living donors. Hence, this review aims to provide a comprehensive outline of the current landscape of living liver and kidney transplantation, with a focus on the mental health and wellbeing of donors. As highlighted in previous studies, organ donation has a significant impact on both physical and mental aspects of donor wellbeing, with marked deteriorations occurring in the short term. Furthermore, other qualitative aspects such as financial burden contribute greatly to donor distress, reflecting a need for improved donor care. To address these pertinent issues, recommendations for a successful transplant program are detailed in this review, which encompasses psychological and social aspects of donor care throughout the donation process. Further research can be done on the impact of recipient deaths on donor QOL and appropriate interventions. Overall, given the selfless sacrifices of living donors, the care of their mental wellbeing is essential. Therefore, greater emphasis should be placed on the provision of adequate psychosocial support for them.

Investigation of the prognostic value of psoas muscle area measurement in pediatric patients before liver transplantation: A single-center retrospective study

BACKGROUND

In this study, our aim is to investigate the prognostic value of psoas muscle area (PMA) evaluation before liver transplantation (LT) in pediatric patients.

METHODS

Two hundred seventy-six patients under 18 years of age who underwent LT between January 2012 and December 2019 were included in the study. The patients' demographic, laboratory, clinical, and imaging data were scanned retrospectively. PMA was measured at the L4/5 level using computed tomography images. To determine reproducibility, a different radiologist evaluated 30 randomly selected patients.

RESULTS

In patients with end-stage liver disease (ESLD), PMA was significantly lower than in patients with acute liver failure (P < .001). In patients with ESLD, a weakly significant correlation was found between PMA and 1-year survival after LT (r: .251, P = .030), hospitalization period (r: -.275, P = .039), and pediatric ESLD score (r: -.338, P < .001). Interobserver correlation was excellent (ICC: .941, 95% CI: .925, .971).

CONCLUSION

In children with ESLD, PMA evaluated before LT can be used as a negative prognostic factor.

Pediatric metabolic liver diseases: Evolving role of liver transplantation

Metabolic liver diseases (MLD) are the second most common indication for liver transplantation (LT) in children. This is based on the fact that the majority of enzymes involved in various metabolic pathways are present within the liver and LT can cure or at least control the disease manifestation. LT is also performed in metabolic disorders for end-stage liver disease, its sequelae including hepatocellular cancer. It is also performed for preventing metabolic crisis’, arresting progression of neurological dysfunction with a potential to reverse symptoms in some cases and for preventing damage to end organs like kidneys as in the case of primary hyperoxalosis and methyl malonic acidemia. Pathological findings in explant liver with patients with metabolic disease include unremarkable liver to steatosis, cholestasis, inflammation, variable amount of fibrosis, and cirrhosis. The outcome of LT in metabolic disorders is excellent except for patients with mitochondrial disorders where significant extrahepatic involvement leads to poor outcomes and hence considered a contraindication for LT. A major advantage of LT is that in the post-operative period most patients can discontinue the special formula which they were having prior to the transplant and this increases their well-being and improves growth parameters. Auxiliary partial orthotopic LT has been described for patients with noncirrhotic MLD where a segmental graft is implanted in an orthotopic position after partial resection of the native liver. The retained native liver can be the potential target for future gene therapy when it becomes a clinical reality.

Dermatologic manifestations in pediatric patients after liver and HSCT: A 20-year retrospective cohort study

LT and HSCT are now potentially curative treatments for many medical conditions. Dermatologic manifestations are one of the sequelae after transplantation. To study the prevalence and associated risk factors of dermatologic manifestations after pediatric LT and HSCT. A 20-year retrospective cohort study was conducted in children, aged ≤15 years, who received LT or HSCT from January 1, 1997, to December 31, 2017. Medical records were reviewed for data collection until December 31, 2018. A total of 70 LT and 51 HSCT recipients were included. The percentages of overall dermatologic manifestations after LT and HSCT were 64.3% and 64.7%, respectively. Viral infection was the most common manifestation in both groups, with mucocutaneous HSV infection as the most prevalent. One HSCT recipient developed leukemia cutis. GVHD was revealed in 27.5% of HSCT recipients. Impetigo and xerosis were significantly observed in patients using azathioprine and prednisolone. Approximately two-thirds of pediatric LT and HSCT recipients experienced dermatologic manifestations, potentially associated with immunosuppressive agents. Thus, regular skin examination and optimized immunosuppression would be beneficial in these recipients.

Gastrointestinal perforations and associated risk factors in children after liver transplantation

In this study, possible risk factors of gastrointestinal perforations (GIP) that increase mortality after liver transplantation in children were investigated. One hundred and thirty-one pediatric patients who underwent 139 liver transplants between January 2016 and February 2020 were evaluated retrospectively based on preoperative and surgical data. Furthermore, cases with biliary atresia, which constitute 26.7% (35) of the patients, were compared within themselves and with other groups. It was found that the cases that developed perforations were younger, lower in weight, and had higher number of surgeries than those who did not, while the mortality and morbidity rates were higher in these patients. When cases with biliary atresia were analyzed within themselves, no significant difference was found between perforated biliary atresia and non-perforated cases in terms of age, weight, and previous surgery. When biliary atresia and other etiologies were compared, biliary atresia cases were found to be transplanted at a younger age, at a lower weight, and this group had a higher risk for perforation. Early laparotomy should be performed in order to reduce mortality in GIPs. Patients that are younger, underweight, previously operated, and using mesh must be closely monitored.

[Application of double plasma molecular adsorption system in children with acute liver failure]

OBJECTIVE

To study the efficacy and safety of double plasma molecular absorption system (DPMAS) in the treatment of pediatric acute liver failure (PALF).

METHODS

A prospective analysis was performed on the medical data of children with PALF who were hospitalized in the Intensive Care Unit (ICU), Hunan Children's Hospital, from March 2018 to June 2020. The children were randomly divided into two groups:plasma exchange group (PE group) and DPMAS group (n=18 each). The two groups were compared in terms of clinical indices after treatment, laboratory markers before and after treatment, and adverse events after treatment.

RESULTS

Compared with the PE group, the DPMAS group had a significantly lower number of times of artificial liver support therapy and a significantly shorter duration of ICU stay (P < 0.05), while there was no significant difference in the 12-week survival rate between the two groups (P > 0.05). There was no significant difference in laboratory markers between the two groups before treatment (P > 0.05). After treatment, both groups had reductions in the levels of total bilirubin, interleukin-6, and tumor necrosis factor-α, and the DPMAS group had significantly greater reductions than the PE group (P < 0.05). Both groups had a significant reduction in alanine aminotransferase (P < 0.05), while there was no significant difference between the two groups (P > 0.05). The PE group had a significant increase in albumin, while the DPMAS group had a significant reduction in albumin (P < 0.05). The PE group had a significant reduction in prothrombin time, while the DPMAS group had a significant increase in prothrombin time (P < 0.05). There was no significant difference between the two groups in the rebound rate of total bilirubin and the overall incidence rate of adverse events after treatment (P > 0.05).

CONCLUSIONS

DPMAS is safe and effective in the treatment of PALF and can thus be used as an alternative to artificial liver support therapy.

Living donor liver transplantation for pediatric patients with metabolic disease vs. deceased donation

BACKGROUND

There are conflicting reports on the outcomes of patients with metabolic liver disease after liver transplantation. We aimed to compare the outcomes of living donor liver transplantation (LDLT) for metabolic disease vs orthotopic liver transplantation (OLT) from deceased donation.

METHODS

Clinical data of 89 patients undergoing liver transplantation for the treatment of metabolic disorders were reviewed. Pre- and peri-transplant demographics, survival rate, complications and laboratory test data were collected and analyzed.

RESULTS

For the 89 patients, only 2 died by the end of the last follow-up. The post-transplant EAD rate and severe complications were higher for OLT than LDLT. No significant difference was found between LDLT and OLT for the incidence of EBV and CMV infections. In terms of laboratory indexes, the recovery time of PLT, AKP and AST levels were significantly longer for OLT than LDLT. Among different types of metabolic disease, no significant difference was found in viral infection, EAD, laboratory indexes, severe complications or duration of hospital stay.

CONCLUSIONS

LDLT shows a lower incidence rate of EAD and complications, while it also shows a 1-year survival rate and incidence of viral infections compared similar to that of OLT. LDLT is the better treatment option of pediatric liver transplantation for metabolic liver disease compared with OLT.

Effect of remote ischemic preconditioning among donors and recipients following pediatric liver transplantation: A randomized clinical trial

BACKGROUND

Studies suggested that remote ischemic preconditioning (RIPC) may effectively lessen the harmful effects of ischemia reperfusion injury during organ transplantation surgery.

AIM

To investigate the protective effects of RIPC on living liver donors and recipients following pediatric liver transplantation.

METHODS

From January 2016 to January 2019 at Renji Hospital Affiliated with Shanghai Jiao Tong University School of Medicine, 208 donors were recruited and randomly assigned to four groups: S-RIPC group (no intervention; n = 55), D-RIPC group (donors received RIPC; n = 51), R-RIPC group (recipients received RIPC, n = 51) and DR-RIPC group (both donors and recipients received RIPC; n = 51). We primarily evaluated postoperative liver function among donors and recipients and incidences of early allograft dysfunction, primary nonfunction and postoperative complications among recipients.

RESULTS

RIPC did not significantly improve alanine transaminase and aspartate aminotransferase levels among donors and recipients or decrease the incidences of early allograft dysfunction, primary nonfunction, and postoperative complications among recipients. Limited protective effects were observed, including a lower creatinine level in the D-RIPC group than in the S-RIPC group on postoperative day 0 (P < 0.05). However, no significant improvements were found in donors who received RIPC. Furthermore, RIPC had no effects on the overall survival of recipients.

CONCLUSION

The protective effects of RIPC were limited for recipients who received living liver transplantation, and no significant improvement of the prognosis was observed in recipients.

Modified Dual Hepatic Vein Anastomosis in Pediatric Living-Donor Liver Transplantation Using Left Lateral Segment Grafts With Two Wide Orifices

Background: The anatomic variation of hepatic vein in the left lateral segment (LLS) increases the risk of outflow complication in pediatric living liver transplantation (LDLT). Here, we share a modified method for dual hepatic vein reconstruction in pediatric LDLT using LLS with two wide orifices. Methods: From Sep 2018 to Dec 2019, 434 pediatric LDLTs using LLS were performed in our center. Hepatic veins of grafts were classified into three types with emphasis on the number, size, and location of orifices at the cut surface: a single opening (type I, n = 341, 78.57%); two adjacent orifices (type II, n = 66, 15.21%); two wide orifices with orifices distances <20 mm (type IIIa, n = 15, 3.46%); and two wide orifices with orifices distances >20 mm (type IIIb, n = 12, 2.76%). Rv was defined as the ratio of diameter of V2 and V3 (refer to hepatic vein drained segments II and III). We developed a modified dual hepatic vein anastomosis to reconstruct outflow for type IIIb grafts with Rv ≤1. Briefly, the hepatic vein of segment II was anastomosed to the common stump of middle hepatic vein (MHV) and left hepatic vein (LHV), followed by unification of V3 and the longitudinal incision orifice in inferior venous cave (IVC). Results: During median follow-up of 15.6 months (7.5-22.9 months), no hepatic vein complications occurred. Conclusion: This novel modified dual hepatic vein anastomosis could serve as a feasible surgical option for type IIIb LLS grafts with Rv ≤1 in pediatric LDLT.

Higher Waitlist Mortality in Pediatric Acute-on-chronic Liver Failure in the UNOS Database

OBJECTIVES

Acute-on-chronic liver failure (ACLF), whereas increasingly well-defined in adults, has been poorly characterized in pediatric patients other than having a poor prognosis. This study aimed to identify ACLF and evaluate prognosis in the American pediatric population.

METHODS

Modified ACLF definitions (p-CLIF) were applied to 11,300 children listed for liver transplantation from March 2002 through 2017 in the Organ Procurement and Transplantation Network (OPTN) database.

RESULTS

Pediatric ACLF patients have greater mortality within 90 days from listing (46.6% by p-CLIF) than other types of failure (<30%), including acute liver failure, as well as greater mortality within the first 30 and 90 days after transplantation than all other types of liver failure, but do not have increased mortality rates relative to other groups between 90 and 365 days from transplant. Although some ACLF listings also received 1B status, ACLF mortality at 90 days was greater than the general 1B population (50 vs 29.4%). Model for End-Stage Liver Disease/Pediatric End-Stage Liver Disease scores of ACLF patients are lower than 1B listings, and do not predict waitlist or posttransplant death. Greater number of organ failures does correlate with increased mortality. Biliary atresia is the leading etiology of pediatric chronic liver disease, accounting for over 30% of chronic and 45% of ACLF listings, yet is protective against mortality (hazard ratio [HR] = 0.142 for ACLF). Receiving exception approval is independently but similarly protective in ACLF (HR = 0.145).

CONCLUSIONS

These findings pose a challenge for allocation decisions but indicate greater attention to ACLF is needed, as scoring systems may not capture these children's risk of early death, which appears to currently be mitigated by exceptions. Multicenter, clinical, preferably prospective study of ACLF is necessary to determine how to prioritize ACLF relative to other liver failure types to address its relatively higher early mortality.

Gene Therapy for Progressive Familial Intrahepatic Cholestasis: Current Progress and Future Prospects

Progressive Familial Intrahepatic Cholestasis (PFIC) are inherited severe liver disorders presenting early in life, with high serum bile salt and bilirubin levels. Six types have been reported, two of these are caused by deficiency of an ABC transporter; ABCB11 (bile salt export pump) in type 2; ABCB4 (phosphatidylcholine floppase) in type 3. In addition, ABCB11 function is affected in 3 other types of PFIC. A lack of effective treatment makes a liver transplantation necessary in most patients. In view of long-term adverse effects, for instance due to life-long immune suppression needed to prevent organ rejection, gene therapy could be a preferable approach, as supported by proof of concept in animal models for PFIC3. This review discusses the feasibility of gene therapy as an alternative for liver transplantation for all forms of PFIC based on their pathological mechanism. Conclusion: Using presently available gene therapy vectors, major hurdles need to be overcome to make gene therapy for all types of PFIC a reality.

High Frequency of Concomitant Food Allergy Development and Autoantibody Formation in Children Who Have Undergone Liver Transplantation

BACKGROUND

Allergy and other immune-mediated diseases are more frequently reported in children who have undergone liver transplantation. Furthermore, autoantibodies are also prevalent, suggesting a state of immune dysregulation in these patients. Whether or not these processes occur simultaneously in the same individual has not been studied previously.

METHODS

A cohort of 43 children who had undergone liver transplantation for nonautoimmune liver disease at median age of 1.3 years was investigated for allergy and autoimmune disease. Sensitization to food and inhalant allergens was assessed, and autoantibodies were measured.

RESULTS

The prevalence of food allergy was 26% and that of respiratory allergy was 23%, whereas 33% and 26% of the subjects were sensitized to food and inhalant allergens, respectively. Autoimmune disease (ie, autoimmune hepatitis) occurred in a single individual (2%), whereas autoantibodies were present in 44% of the children. Food allergy and autoantibodies occurred concomitantly in 19% of the children, which was almost twice the frequency expected by chance (11%, P = 0.04). Respiratory allergy and the presence of autoantibodies were unrelated (12% concurrence versus the expected 10%, P = 0.73). In the logistic regression analysis, autoantibody formation was associated with discontinued immunosuppression and food allergy, with odds ratios of 13 (P = 0.01) and 7.1 (P = 0.03), respectively.

CONCLUSIONS

In contrast to respiratory allergy, food allergy and autoantibody formation occurred together in the same children who underwent liver transplantation at a frequency higher than would be expected by chance. This may reflect an underlying immune dysregulation that impairs immune tolerance to both food allergens and autoantigens.

Etiology of liver dysfunction after liver transplantation in children with metabolic disorders

AIM

It has been reported that the long-term outcome for children with metabolic disorders after liver transplantation (LT) is excellent. However, there are several reports citing LT patients with metabolic disorders developing liver dysfunction early after LT. We examined the pathogenesis of liver dysfunction observed after LT in recipients with metabolic disorders at the National Center for Child Health and Development.

METHODS

Of 106 children (aged <18 years) with metabolic disorders who underwent LT at our center, 36 patients who underwent liver biopsy within 60 days after LT were enrolled. The underlying diseases were urea cycle disorders (14 patients), methylmalonic acidemia (11 cases), Wilson's disease (3 patients), mitochondrial hepatopathy (3 patients), and others (5 patients). The median age was 1 year 2 months at LT. The reasons for biopsy were liver dysfunction (31 patients) and ascites (5 patients).

RESULTS

The main findings of graft liver biopsy were diffuse steatosis (21 patients), rejection (8 patients), infection (3 patients), and others (4 patients). Of 21 patients who received graft biopsy showing steatosis, all the donor livers originally showed no steatosis or only mild steatosis. The liver function improved immediately after biopsy in 18 of 21 patients that showed diffuse steatosis.

CONCLUSIONS

The major cause of liver dysfunction after LT in recipients with metabolic disorders was steatosis and the risk of rejection was low. It is important to take a liver biopsy and examine the cause of liver dysfunction to avoid administration of excess immunosuppressant, and select the right therapy for recipients with metabolic disorders.