Pediatric liver transplantation

BiliQML: a supervised machine-learning model to quantify biliary forms from digitized whole slide liver histopathological images

The progress of research focused on cholangiocytes and the biliary tree during development and following injury is hindered by limited available quantitative methodologies. Current techniques include two-dimensional standard histological cell-counting approaches, which are rapidly performed, error prone, and lack architectural context or three-dimensional analysis of the biliary tree in opacified livers, which introduce technical issues along with minimal quantitation. The present study aims to fill these quantitative gaps with a supervised machine-learning model (BiliQML) able to quantify biliary forms in the liver of anti-keratin 19 antibody-stained whole slide images. Training utilized 5,019 researcher-labeled biliary forms, which following feature selection, and algorithm optimization, generated an F score of 0.87. Application of BiliQML on seven separate cholangiopathy models [genetic (Afp-CRE;Pkd1l1null/Fl, Alb-CRE;Rbp-jkfl/fl, and Albumin-CRE;ROSANICD), surgical (bile duct ligation), toxicological (3,5-diethoxycarbonyl-1,4-dihydrocollidine), and therapeutic (Cyp2c70-/- with ileal bile acid transporter inhibition)] allowed for a means to validate the capabilities and utility of this platform. The results from BiliQML quantification revealed biological and pathological differences across these seven diverse models, indicating a highly sensitive, robust, and scalable methodology for the quantification of distinct biliary forms. BiliQML is the first comprehensive machine-learning platform for biliary form analysis, adding much-needed morphologic context to standard immunofluorescence-based histology, and provides clinical and basic science researchers with a novel tool for the characterization of cholangiopathies.NEW & NOTEWORTHY BiliQML is the first comprehensive machine-learning platform for biliary form analysis in whole slide histopathological images. This platform provides clinical and basic science researchers with a novel tool for the improved quantification and characterization of biliary tract disorders.

Utilization of older deceased donors for pediatric liver transplant may negatively impact long-term survival

BACKGROUND

Multiple adult studies have investigated the role of older donors (ODs) in expanding the donor pool. However, the impact of donor age on pediatric liver transplantation (LT) has not been fully elucidated.

METHODS

UNOS database was used to identify pediatric (≤18 years) LTs performed in the United States during 2002-22. Donors ≥40 years at donation were classified as older donors (ODs). Propensity analysis was performed with 1:1 matching for potentially confounding variables.

RESULTS

A total of 10,024 pediatric liver transplantation (PLT) patients met inclusion criteria; 669 received liver grafts from ODs. Candidates receiving OD liver grafts were more likely to be transplanted for acute liver failure, have higher Model End-Stage Liver Disease/Pediatric End-Stage Liver Disease (MELD/PELD) scores at LT, listed as Status 1/1A at LT, and be in the intensive care unit (ICU) at time of LT (all p < 0.001). Kaplan-Meier (KM) analyses showed that recipients of OD grafts had worse patient and graft survival (p < 0.001) compared to recipients of younger donor (YD) grafts. KM analyses performed on candidates matched for acuity at LT revealed inferior patient and graft survival in recipients of deceased donor grafts (p < 0.001), but not living donor grafts (p > 0.1) from ODs. Cox regression analysis demonstrated that living donor LT, diagnosis of biliary atresia and first liver transplant were favorable predictors of recipient outcomes, whereas ICU stay before LT and transplantation during 2002-12 were unfavorable.

CONCLUSION

Livers from ODs were used for candidates with higher acuity. Pediatric recipients of livers from ODs had worse outcome compared to YDs; however, living donor LT from ODs had the least negative impact on recipient outcomes.

Etiology, risk factors and management of hypertension post liver transplantation

BACKGROUND

Cardiovascular events are one of the most important causes of morbidity and mortality in the long-term follow-up of liver transplant recipients. Hypertension is a significant cardiovascular risk factor that occurs frequently after pediatric liver transplantation. Chronic use of immunosuppressants - mainly calcineurin inhibitors - plays a major role in the development of post-transplant hypertension and circadian disturbances such as flattening of the nocturnal blood pressure dip. This requires special attention in children given the long timeframe during which immunosuppressive therapy is necessary. Careful and structured blood pressure monitoring and adequate treatment of hypertension are essential to optimize the quality of life and life expectancy of pediatric liver transplant patients. However, evidence-based guidelines for monitoring and management of post-transplant hypertension and its complications are lacking.

METHODS

We conducted a comprehensive review of the current knowledge and practices concerning post-transplant hypertension. The databases Pubmed, Embase, Web of Science and Google Scholar were scanned with the following keywords: pediatric liver transplantation, immunosuppression, tacrolimus, cardiovascular effects, hypertension, heart function, kidney function, circadian rhythm, mechanism, monitoring, and management.

RESULTS

In this review, we describe the incidence and etiology of hypertension in pediatric liver transplant recipients, the underlying mechanisms and characteristics of calcineurin inhibitor-induced hypertension, and the consequences of and risk factors for post-transplant hypertension. We hereby present an overview of the current practices in blood pressure monitoring and antihypertensive treatment as well as an algorithm for the evaluation and management of hypertension post liver transplantation. Finally, we discuss knowledge gaps and suggestions for future research.

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.

Pediatric Transplant Interventions

The field of pediatric organ transplantation has grown significantly in recent decades, with interventional radiology (IR) playing an essential role in managing pre and post-transplant complications. Pediatric transplant patients face unique challenges compared to adults, including donor-recipient size mismatch, and complications of a growing child with changing physiology. Interventional radiologists play a major role in pediatric renal and liver transplant. IR interventions begin early in the child's pretransplant journey, with diagnostic procedures such as biopsies, angiograms, and cholangiograms. These procedures are essential for understanding the etiology of organ failure and identifying potential transplant candidates. Minimally invasive therapeutic procedures may serve as bridges to transplant and may include vascular access optimization for hemodialysis, transjugular intrahepatic portosystemic shunts (TIPS) creation, and tumor embolization or ablation. After transplant, image-guided biopsies for the surveillance of graft rejection and treatment of vascular or luminal stenoses, pseudoaneurysms, and anastomotic leaks can maintain the function and longevity of the transplant organ. Careful consideration must be given to patient size and evolving anatomy, radiation exposure, and the need for deeper sedation for pediatric patients. Despite these challenges, the integration of IR in pediatric transplant care has proven beneficial, offering minimally invasive alternatives to surgery, faster recovery times, and improved outcomes.

Postoperative Bloodstream Infection Is Associated with Early Vascular Complications in Pediatric Liver Transplant Recipients with Biliary Atresia

Bloodstream infection (BSI) after pediatric liver transplantation (PLT) is a common and severe complication that affects patient survival. Children with biliary atresia (BA) are at an increased risk for clinically significant infections. This study evaluated the impact of post-PLT BSI on clinical outcomes in children with BA. A total of 67 patients with BA aged <18 years who underwent PLT between April 2006 and September 2020 were analyzed and divided into two groups according to the occurrence of post-PLT BSI within 1 month (BSI vs. no BSI = 13 [19.4%] vs. 54 [80.6%]). The BSI group was significantly younger at the time of PLT and had a higher frequency of BSI at the time of PLT than the no BSI group. Early vascular complications within 3 months and reoperations were significantly more frequent in the BSI group. Univariate and multivariate analyses revealed that bacteremia within 1 month of PLT and graft-to-recipient weight ratio >4% were significantly associated with vascular complications. In conclusion, BSI after PLT is associated with increased vascular complications and reoperations. Proper control of bacterial infections and early liver transplantation before uncontrolled BSI may reduce vascular complications and unexpected reoperations in children with BA.

Immunological Nuances and Complications of Pediatric Organ Transplant: A Narrative Review

Organ transplantation is considered an exaggerated immune state in which the body reacts in an elaborate cascade of reactions against the lifesaving graft transplanted. Unrepairable organ damage is the main indication for a pediatric patient to undergo a transplant. The host and the donor must fulfill the criteria for a successful transplant to have as few side effects as possible. There has been much-needed research in the domain of surgery of organ transplantation, thereby extending into the pediatric age group. This article elaborates on the post-transplant management, the immuno-biochemistry aspect, and its post-surgery treatment. The post-surgery period requires great emphasis as morbidity and mortality are highest. There is much to understand about managing transplant patients to avoid complications such as infections, hypertension, or side effects of immunosuppressive drugs. The treating clinician faces the challenges of managing the dose and frequency of immuno-suppressive medicines to prevent complications in the patients. If the dose is inadequate, there are chances of graft rejection. If the immuno-suppression is prolonged, there may be chances of infections in the patient. This article aims to summarize the mechanism of graft rejection and put forth the need for further research about creating a universal protocol for managing a patient's immune system post-transplant. The authors hope this protocol will help the clinician better understand the patient's current state and help in appropriately using immuno-suppressive drugs. It calls upon the need for a reliable and easily repeatable battery of investigations that will help solve this dilemma.

Imaging and Intervention in the Management of Vascular Complications Following Liver Transplantation

Liver transplantation is the treatment of choice in majority of the patients with end stage liver disease. Vascular complication following liver transplantation is seen in around 7-13% of the patients and is associated with graft dysfunction and high morbidity and mortality. Early diagnosis and prompt treatment are crucial in management of these patients. Advances in interventional radiology have significantly improved the management of vascular complications using minimally invasive percutaneous approach. Endovascular management is preferred in patients with late hepatic artery thrombosis, or stenosis, whereas retransplantation, surgical revision, or endovascular management can be considered in patients with early hepatic artery thrombosis or stenosis. Hepatic artery pseudoaneurysm, arterioportal fistula, and splenic artery steal syndrome are often treated by endovascular means. Endovascular management is also preferred in patients with symptomatic portal vein stenosis, early portal vein thrombosis, and symptomatic late portal vein thrombosis, whereas surgical revision or retransplantation is preferred in patients with perioperative portal vein thrombosis occurring within 3 days of transplantation. Venoplasty with or without stent placement can be considered in patients with hepatic venous outflow tract or inferior vena cava obstruction. Transjugular intrahepatic portosystemic shunt (TIPS) may be required in transplant recipients who develop cirrhosis, often, secondary to disease recurrence, or chronic rejection. Indications for TIPS remain same in the transplant patients; however, major difference is altered vascular anatomy, for which adjunct techniques may be required to create TIPS.

Portal Dynamics After Living Donor Liver Transplant in Pediatric Recipients: A 10-Year Follow-Up Retrospective Study

BACKGROUND

It may be difficult for pediatric patients to evaluate the impact of liver transplantation (LT) on splenomegaly due to the natural growth course. The long-term dynamics of portal vein (PV) size and PV flow after LT in pediatric patients are unclear. We aimed to evaluate the long-term transition of the splenic size, PV size, and PV flow velocity in pediatric patients who underwent successful living donor liver transplantation (LDLT) and survived >10 years.

METHODS

From October 2004 to December 2010, 39 pediatric patients (25 boys; 14 girls) underwent LDLT, received pre-LDLT and post-LDLT computed tomography scans and long-term ultrasound sonography follow-up, and survived >10 years without additional intervention at our institution. We analyzed the short- to mid-term and long-term impact of LDLT on splenic size, PV size, and PV flow velocity over time.

RESULTS

The PV diameter increased throughout the 10-year follow-up (P < .001). The PV flow velocity increased 1 day after LDLT (P< .001); proceeded to decrease 3 days after LDLT, reaching a low point 6 to 9 months after LDLT; and remained stable throughout the 10-year follow-up. Regression of the splenic volume at 6 to 9 months after LDLT (P < .001) was noted. However, the splenic size steadily increased on long-term follow-up.

CONCLUSIONS

Although LDLT has a significant short-term reduction effect on splenomegaly, the long-term transitional trend of the splenic size and PV diameter may increase along with children's growth. The PV flow reached a stable status 6 to 9 months after LDLT and remained so until 10 years after LDLT.

Opportunities and considerations for studying liver disease with microphysiological systems on a chip

Advances in microsystem engineering have enabled the development of highly controlled models of the liver that better recapitulate the unique in vivo biological conditions. In just a few short years, substantial progress has been made in creating complex mono- and multi-cellular models that mimic key metabolic, structural, and oxygen gradients crucial for liver function. Here we review: 1) the state-of-the-art in liver-centric microphysiological systems and 2) the array of liver diseases and pressing biological and therapeutic challenges which could be investigated with these systems. The engineering community has unique opportunities to innovate with new liver-on-a-chip devices and partner with biomedical researchers to usher in a new era of understanding of the molecular and cellular contributors to liver diseases and identify and test rational therapeutic modalities.

Comparing the Outcomes of Pediatric Liver Transplantation

BACKGROUND

Liver transplantation is a life-saving treatment for end-stage pediatric liver failure. We aimed to present the results of pediatric liver transplants performed in our center in the last 11 years (between 2012 and March 2022) in association with prognostic factors affecting survival.

METHODS

Demographic characteristics, etiologic reasons, previous operations (Kasai procedure), morbidity, mortality, survival, and bilio-vascular complication rates were determined, and outcomes were evaluated. In the postoperative period, the duration of mechanical ventilation and intensive care unit stay and surgical and other complications were evaluated. Graft and patient survival rates were determined, and univariate and multivariate factors affecting these rates were evaluated.

RESULTS

In the last 10 years, 229 pediatric liver transplantaion (Pe-LT)/1513 adult liver taransplantation (Ad-LT) (21.35%) were performed in our center. This ratio (Pe-LT/Ad-LT ratio) is 1741/15,886 (10.95%) for our country. A total of 229 liver transplants were performed in 214 pediatric patients. Retransplantation was performed in 15 patients (6.55%). Cadaveric liver transplantation was performed in 9 patients. Graft survival rates were 87%, 83%, 78%, 78%, 78%, and 78% at <30 days, 30 to 90 days, 91 to 364 days, 1 to 3 years, and >3 years, respectively. Patient survival rates for <30 days, 30 to 90 days, 91 to 364 days, 1 to 3 years, and >3 years were 91.5%, 85.7%, 82%, 81.5%, and 81.5%, respectively. Our 5-year survival rates in metabolic diseases and the acute fulminant failure group are 93.8% and 100%, respectively.

CONCLUSIONS

The fact that the 1- and 5-year survival rates are the same shows that when patients overcome biliary vascular and infectious problems, their survival is prolonged.

Long-term mortality in pediatric solid organ recipients-A nationwide study

BACKGROUND

The present study aimed at investigating long-term mortality of patients who underwent solid organ transplantation during childhood and at identifying their causes of death.

METHODS

A cohort of 233 pediatric solid organ transplant recipients who had a kidney, liver, or heart transplantation between 1982 and 2015 in Finland were studied. Year of birth-, sex-, and hometown-matched controls (n = 1157) were identified using the Population Register Center registry. The Causes of Death Registry was utilized to identify the causes of death.

RESULTS

Among the transplant recipients, there were 60 (25.8%) deaths (median follow-up 18.0 years, interquartile range of 11.0-23.0 years). Transplant recipients' risk of death was nearly 130-fold higher than that of the controls (95% CI 51.9-1784.6). The 20-year survival rates for kidney, liver, and heart recipients were 86.1% (95% CI 79.9%-92.3%), 58.5% (95% CI 46.2%-74.1%), and 61.4% (95% CI 48.1%-78.4%), respectively. The most common causes of death were cardiovascular diseases (23%), infections (22%), and malignancies (17%). There were no significant differences in survival based on sex or transplantation era.

CONCLUSION

The late mortality is still significantly higher among pediatric solid organ recipients in comparison with controls. Cardiovascular complications, infections, and cancers are the main causes of late mortality for all studied transplant groups. These findings emphasize the cruciality of careful monitoring of pediatric transplant recipients in order to reduce long-term mortality.

Examining need and capacity for the development of a pediatric liver transplantation program in Kenya

BACKGROUND

In Africa, pediatric liver transplantation (PLT) is currently only performed in Egypt and South Africa, leaving those who require treatment in Kenya to travel abroad. The aim of this study was to determine whether sufficient capacity and need exists in Kenya to establish a safe and sustainable PLT program.

METHODS

A descriptive analysis of the intensive care unit (ICU) beds, surgical workforce, current hepatobiliary volume, and estimated prevalence of pediatric liver disease (PLD) was conducted across 17 hospitals in Kenya between July and September 2020. Data were collected from medical superintendents, directors of surgical departments, or nominated proxies at Kenyan Level 5 and 6 hospitals via a web-based survey.

RESULTS

A total of 165 ICU beds were reported at 17 facilities, with 15 facilities reporting five or more beds. About 39% of general surgeons at responding hospitals performed hepatobiliary procedures, and 30% performed pediatric surgeries. Only 10% of surgeons had pediatric training. Over half (57%) of hospitals performed hepatobiliary procedures; at the maximum, 1-5 cases were performed per week including cholecystectomy to Kasai portoenterostomy and hepatectomy. Across 13 hospitals, there were an estimated 192-570 cases of PLD seen per month. The most common PLDs were hepatitis B, neonatal hepatitis, cirrhosis, and acute hepatic failure. Overall, two hospitals possessed the minimum workforce and resources to attempt PLT.

CONCLUSIONS

In Kenya, ICU bed availability, pediatric surgical training, and hepatobiliary volume are limited. However, the high prevalence of PLD demonstrated a significant need for PLT across all Kenyan hospitals.

Disparate Intent-to-Treat Outcomes for Pediatric Liver Transplantation Based on Indication

Background

The impact of indication for pediatric liver transplantation on waitlist and post-transplant mortality outcomes is well known, but the impact on intent-to-treat outcomes has not been investigated. Intent-to-treat survival analysis is important in this study because it is more comprehensive, combining the transplant outcomes of waitlist mortality, post-transplant mortality, and transplant rate into a single metric to elucidate any disparities in outcomes based on indication.

Methods

Cox regression was used to analyze factors impacting survival in 8,002 children listed for liver transplant in the UNOS database between 2006 and 2016. The Kaplan-Meier method and log-rank test were used to assess differences in waitlist, post-transplant, and intent-to-treat mortality among the top 5 indications of biliary atresia, acute hepatic necrosis, metabolic disorders, hepatoblastoma, and autoimmune cirrhosis.

Results

When compared to the reference group of biliary atresia, multivariate analyses showed that every indication was associated with inferior intent-to-treat outcomes except for metabolic disorders. Hepatoblastoma (hazard ratio (HR): 3.73), autoimmune cirrhosis (HR: 1.86), and AHN (HR: 1.77) were associated with significantly increased intent-to-treat mortality. Hepatoblastoma was also associated with increased post-transplant mortality (HR: 3.77) and was the only indication significantly associated with increased waitlist mortality (HR: 6.43).

Conclusion

Significant disparity exists across all indications with respect to an increased intent-to-treat mortality, along with an increased post-transplant and waitlist mortality, when compared to the biliary atresia reference group. If further studies validate these findings, a reexamination of the equitable distribution of allografts for transplant may be warranted as well as a focus on disparities in survival after transplant.

Organoids and regenerative hepatology

The burden of liver diseases is increasing worldwide, with liver transplantation remaining the only treatment option for end-stage liver disease. Regenerative medicine holds great potential as a therapeutic alternative, aiming to repair or replace damaged liver tissue with healthy functional cells. The properties of the cells used are critical for the efficacy of this approach. The advent of liver organoids has not only offered new insights into human physiology and pathophysiology, but also provided an optimal source of cells for regenerative medicine and translational applications. Here, we discuss various historical aspects of 3D organoid culture, how it has been applied to the hepatobiliary system, and how organoid technology intersects with the emerging global field of liver regenerative medicine. We outline the hepatocyte, cholangiocyte, and nonparenchymal organoids systems available and discuss their advantages and limitations for regenerative medicine as well as future directions.

[Postoperative Imaging Findings of Biliary Atresia]

The Kasai portoenterostomy is the first-line treatment for the restoration of the flow of bile to the small intestine in patients with biliary atresia. Various complications can occur after Kasai portoenterostomy, including ascending cholangitis, biliary cirrhosis, and portal hypertension. Of these potential complications, ascending cholangitis in the most common. In cases of patients having uncontrolled complications due to progressive liver cirrhosis, portal hypertension, or progressive hyperbilirubinemia, liver transplantation is the indicated as treatment plan. Lifelong follow-up, particularly involving imaging studies, is important for the identification of various complications arising from biliary atresia after Kasai portoenterostomy. Additionally, imaging studies play a crucial role in the evaluation of potential liver donors and recipients. US is a key imaging modality utilized in the management of patients who undergo Kasai portoenterostomy, while CT and MRI are imperative to obtaining an accurate diagnosis.

Human Cholangiocytes Form a Polarized and Functional Bile Duct on Hollow Fiber Membranes

Liver diseases affect hundreds of millions of people worldwide; most often the hepatocytes or cholangiocytes are damaged. Diseases of the biliary tract cause severe patient burden, and cholangiocytes, the cells lining the biliary tract, are sensitive to numerous drugs. Therefore, investigations into proper cholangiocyte functions are of utmost importance, which is restricted, in vitro, by the lack of primary human cholangiocytes allowing such screening. To investigate biliary function, including transepithelial transport, cholangiocytes must be cultured as three-dimensional (3D) ductular structures. We previously established murine intrahepatic cholangiocyte organoid-derived cholangiocyte-like cells (CLCs) and cultured them onto polyethersulfone hollow fiber membranes (HFMs) to generate 3D duct structures that resemble native bile ducts at the structural and functional level. Here, we established an efficient, stepwise method for directed differentiation of human intrahepatic cholangiocyte organoids (ICOs) into CLCs. Human ICO-derived CLCs showed key characteristics of cholangiocytes, such as the expression of structural and functional markers, formation of primary cilia, and P-glycoprotein-mediated transport in a polarized fashion. The organoid cultures exhibit farnesoid X receptor (FXR)-dependent functions that are vital to liver bile acid homeostasis in vivo. Furthermore, human ICO-derived CLCs cultured on HFMs in a differentiation medium form tubular architecture with some tight, confluent, and polarized monolayers that better mimic native bile duct characteristics than differentiated cultures in standard 2D or Matrigel-based 3D culture plates. Together, our optimized differentiation protocol to obtain CLC organoids, when applied on HFMs to form bioengineered bile ducts, will facilitate studying cholangiopathies and allow developing therapeutic strategies.

Portal plate bile duct diameter in biliary atresia is associated with long-term outcome

PURPOSE

Kasai portoenterostomy (KPE) is the only treatment currently available for biliary atresia (BA). Age at KPE and surgical experience are prognostic factors for a successful KPE. Here, we aimed to assess whether the size of bile ductules at the porta hepatis during KPE correlates with KPE success and transplant-free survival (TFS).

METHODS

A retrospective analysis of patients diagnosed with BA during 2000-2019. Porta hepatis biopsies were reviewed for diameters of five representative ducts, and a mean ductal diameter (MDD) was calculated. Laboratory values including pre- and postoperative bilirubin levels were analyzed.

RESULTS

The cohort included 77 patients; for 33, ductal plate biopsy was available. KPE was successful in six of eight patients with MDD ≥ 50 µm, and in five of 25 with MDD < 50 µm, p = 0.008, OR = 12.0 (95% CI 1.83-78.3). Ten-year survival with native liver was higher in patients with MDD ≥ 50 µm than in patients with MDD < 50 µm, p < 0.001, HR 0.038 (95% CI 0.007-0.207). Direct bilirubin < 1 mg/dl 3 months post-KPE was associated with improved 2-year post-KPE TFS (27.7% vs. 13.9%, p < 0.0001).

CONCLUSIONS

MDD ≥ 50 µm correlates with KPE success and a higher rate of TFS. Direct bilirubin < 1 mg/dl 3 months post-operation may serve as a marker of successful biliary excretion, and a predictor of 2-year TFS.

Pediatric Liver Transplantation: Long-Term Follow-Up Issues

Pediatric liver transplant is an established life-saving procedure for children with end-stage liver diseases, achieving excellent graft and patient survival but with effects on quality of life and psychological welfare in the long-term. With the natural increase in the number of pediatric transplant patients becoming adults, it is essential to successfully plan and manage issues affecting late outcomes in the vulnerable pediatric transplant population. This study offers an overview of the long-term surgical complications, the consequences of immunosuppression (such as posttransplant diabetes, hypertension, cardiovascular disease, and renal dysfunction), and the infection and malignancy risks. Finally, because quality of life is now an inclusive measurement of patient satisfaction, guidance on how to facilitate the transition to adulthood, empowering transplant recipients, is also provided.

Factors associated with postoperative respiratory conditions and critical outcomes on pediatric liver transplantation: A single-center experience

BACKGROUND

Orthotopic liver transplantation (OLT) is an established therapeutic option for pediatric end-stage liver disease (PELD). The postoperative respiratory conditions of OLT recipients may be associated with subsequent clinical outcomes including length of stay (LOS) in the pediatric intensive care unit (PICU). This study aimed to characterize the postoperative respiratory conditions, associated factors, and outcomes after pediatric OLT.

METHODS

Clinical data of children receiving OLT from July 2014 to July 2020 were retrospectively collected. Postoperative respiratory conditions were defined as time to extubation, significant pleural effusion, and initial postoperative PaO2/FiO2 ratio. Logistic and multiple regressions were applied to analyze the associations among clinical factors, postoperative respiratory conditions, and clinical outcomes.

RESULTS

Twenty-two patients with median age of 1.4-year-old (range: 25 days to 12 years old) were analyzed. Mortality within 28 days was 4.5% and median LOS in the PICU was 18 days. Of 22 patients, 11 patients (50.0%) were extubated over 24 hours after surgery, and 8 patients (36.4%) required drainage for pleural effusions. Longer LOS in the PICU were noted in patients extubated over 24 hours (p = 0.008), complicated with significant pleural effusions (p = 0.02) after surgery, and having low initial postoperative PaO2/FiO2 (<300 mmHg) (p = 0.001). Among clinical factors, massive intraoperative blood transfusion (>40 mL/kg) was significantly associated with prolonged intubations, significant pleural effusions, low initial postoperative PaO2/FiO2, and prolonged LOS in the PICU (>14 days). The initial postoperative PaO2/FiO2 significantly depended on age, disease severity (PELD score), and whether the patient received massive intraoperative blood transfusion.

CONCLUSION

Pediatric patients of OLT with poor postoperative respiratory conditions including low initial PaO2/FiO2 ratio, extubation over 24 hours or significant pleural effusions have longer LOS in the PICU, and the requirement of massive intraoperative transfusion was a risk factor for both poor postoperative respiratory conditions and prolonged LOS in the PICU.

When Push Comes to Shove! Emergency ABO-Incompatible Pediatric Living Donor Liver Transplant for Acute Wilson's Disease

ABO-incompatible living donor liver transplantation (ABOi-LDLT) is on the rise as a viable option in countries with limited access to deceased donor grafts. While reported outcomes of ABOi-LT in children are similar to ABO- Compatible liver transplant (ABOc-LT), most children beyond 1-2 years of age will need desensitization to overcome the immunological barrier of incompatible blood groups. The current standard protocol for desensitization is Rituximab that targets B lymphocytes and is given 2-3 weeks prior to LT. However, this timeline may not be feasible in children requiring emergency LT for acute liver failure (ALF) or acute-on-chronic liver failure (ACLF). In this emergency situation of ABOi-LT, a safe multipronged approach may be an acceptable alternative solution. We report a child with acute Wilson's disease with rapidly deteriorating liver function who underwent a successful ABOi-LDLT using a rapid desensitization protocol.

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.

Biliary Atresia - emerging diagnostic and therapy opportunities

Biliary Atresia is a devastating pediatric cholangiopathy affecting the bile ducts of the liver. In this review, we describe recent progress in the understanding of liver development with a focus on cholangiocyte differentiation and how use of technical platforms, including rodent, zebrafish and organoid models, advances our understanding of Biliary Atresia. This is followed by a description of potential pathomechanisms, such as autoimmune responses, inflammation, disturbed apical-basal cell polarity, primary cilia dysfunction as well as beta-amyloid accumulation. Finally, we describe current and emerging diagnostic opportunities and recent translation breakthroughs for Biliary Atresia in the area of emerging therapy development, including immunomodulation and organoid-based systems for liver and bile duct repair.

Management of Biliary Stricture in Pediatric Liver Transplantation Patients: Long-Term Outcomes

Postoperative biliary complications have been reported to occur in 10% to 33% of pediatric liver transplantation (LT) recipients. Percutaneous intervention has become the primary treatment method for these complications; however, the efficacy and outcomes of these patients have not been well studied. Institutional pediatric LT from 1998 to 2019 were retrospectively reviewed to determine the patients referred for percutaneous treatment of post-LT biliary strictures. Clinical parameters, percutaneous transhepatic cholangiograms (PTCs), biliary catheter placement, cholangioplasty, and long-term outcomes were analyzed. Of the 396 consecutive pediatric LT recipients during our study period, 50 (12.6%) were diagnosed with biliary strictures on PTC. LT biliary reconstructions were Roux-en-Y hepaticojejunostomy in 28 patients (56%), choledochojejunostomy in 11 patients (22%), and choledochocholedochostomy in 11 patients (22%). Median age at LT was 23.2 months (interquartile range [IQR], 10.9-90.6), and 14 patients (28%) developed hepatic artery thrombosis. A total of 44 patients (88%) were treated with internal/external biliary catheters, of whom 38 (76%) underwent balloon cholangioplasty. By 12 months, 84% of patients had complete stricture resolution and catheter removal. Median total duration of catheter drainage was 152 days (IQR, 76-308). A total of 8 patients required additional surgery (biliary reconstruction or repeat LT [re-LT]) or died with a drainage catheter in place from complications unrelated to PTC intervention. Among the 6 patients (12%) treated with unilateral external biliary drainage catheters, 2 had catheters removed for inadequate drainage but then had spontaneous biliary obstruction resolution, 1 underwent duct reconstruction, and 3 required long-term catheterization. Biliary strictures following pediatric LT can be successfully treated with internal/external biliary drainage catheters and cholangioplasty if the stricture can be crossed. However, patients with isolated strictured ducts may require long-term external catheter drainage until re-LT or percutaneous obliteration of isolated ducts.

Kidney disease in children with heart or liver transplant

Over the past few decades, there has been increasing recognition of kidney disease in children with non-kidney solid organ transplantation. The risk of kidney disease in children undergoing heart or liver transplantation is higher than the general population as the underlying disease and its associated management may directly impair kidney function. Both heart and liver failures contribute to hypoperfusion and kidney ischemia before patients reach the point of transplant. The transplant surgery itself can often be complicated by acute kidney injury (AKI), which may be further exacerbated by a complicated postoperative course. In the short- and long-term post-transplant period, these children are at risk of acute illness, exposed to nephrotoxic medications, and susceptible to rare but severe infections and immunologic insults that may contribute to AKI and chronic kidney disease (CKD). In some, CKD can progress to kidney failure with replacement therapy (KFRT). CKD and KFRT are associated with increased morbidity and mortality in this patient population. Therefore, it is critical to monitor for and recognize the risk factors for kidney injury in this population and mitigate these risks. In this paper, the authors provide an overview of kidney disease pertaining to heart and liver transplantation in children with guidance on monitoring, diagnosis, prevention, and management.

Pediatric deceased donor liver transplantation with in situ size reduction for recipient-graft size matching

We present a case of pediatric deceased donor liver transplantation using a reduced whole liver graft in a 25-month-old boy weighing 12.7 kg. After he had undergone Kasai portoenterostomy for biliary atresia, his general condition deteriorated progressively. He was enrolled on the waiting list for liver transplantation with Pediatric End-stage Liver Disease score of 15. The donor was a 51-monthold boy with body weight of 20 kg. The donor-to-recipient body weight ratio was 158%. The liver graft appeared to be larger than the recipient's abdominal cavity. Thus, we planned to do in situ size reduction. Recipient surgery was performed following standard procedures. We performed graft outflow vein reconstruction using a modified piggyback technique like the double inferior vena cava method. Since the portal vein was hypoplastic, a side-to-side anastomosis technique was used. We also performed intraoperative portogram to embolize venous collaterals. After completing the graft implantation, we found that the liver graft was too large to be accommodated within the abdomen. After in situ resection of the left lateral section parenchyma, we successfully performed primary closure of the abdominal wound. This patient experienced episodes of acute rejection. He has been doing well for four years after the transplantation.

Evaluation of arterial hypertension by ambulatory blood pressure monitoring in pediatric liver transplant recipients

OBJECTIVE

Many cardiovascular complications, including hypertension, are seen in pediatric liver transplantation. The purpose of this study was to analyze the frequency of arterial hypertension of pediatric liver transplant recipients and also to determine the related risk factors.

METHODS

Thirty-six pediatric liver transplant recipients aged 8-17 years were prospectively studied by manual and ambulatory blood pressure measurement (ABPM) technique.

RESULTS

The mean age of patients was 12.42 ± 2.74 years and the mean ABPM measurement time after transplantation was 2 years (3 months-5.9 years). Only one (2.7%) patient was detected as hypertensive by casual measurement, but 17 (47.2%) patients were found to be hypertensive when measured through ABPM. Of children that were found to be hypertensive as a result of ABPM, 64.7% were observed to have a nondipper pattern. Considering the time passed after the transplantation, patients were found to be more hypertensive in the first 2 years posttransplant although it was not found statistically significant.

CONCLUSIONS

In this study, it has been shown that it is possible to diagnose hypertension at an earlier period of transplantation using ABPM in pediatric liver transplant patients. ABPM is needed to detect masked hypertension that may develop following liver transplantation.

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.

Time is of the essence: A single-center experience of hepatic arterial supply impairment management in pediatric liver transplant recipients

BACKGROUND

Impairment of hepatic arterial flow including hepatic arterial thrombosis (HAT), hepatic arterial stenosis (HAS), and splenic artery steal syndrome (SASS) is potentially life-threatening complications. The proposed early diagnosis and urgent treatment strategy of graft arterial flow reduction aim to decrease morbidity and mortality.

METHODS

Pediatric patients with known hepatic arterial flow impairment were retrospectively reviewed. Patients were grouped by occlusive (HAT) and non-occlusive (HAS/SASS) arterial flow reduction. Patients with HAT were further divided in two groups based on the estimated maximal hepatic artery occlusion time ≤8 and >8 hours.

RESULTS

Impairment of hepatic arterial flow developed in 32 of 416 pediatric liver transplant recipients. HAT, HAS, and SASS incidences were 4.1% (n = 17), 2.2% (n = 9), and 1.4% (n = 6), respectively. Neither graft loss nor death occurred in the non-occlusive group. The probabilities of sepsis (OR, 1.7; 95% CI, 1.14-2.53; P=.008) and graft loss or death (OR, 1.42; 95% CI, 1.04-1.92; P=.046) were higher in the occlusive group. Patients with estimated maximal duration of hepatic artery occlusion ≤ 8 hours (n = 7; 41.2%) did not have ischemic-type biliary lesions and sepsis (P=.044 and 0.010, respectively) but had excellent 3-year graft survival compared with > 8 hours group (100% vs 40%; P=.037). Multivariate analysis revealed HAT manifestation by fever was associated with increased chances of graft loss or death.

CONCLUSION

Occlusive arterial complications impose higher risks of graft loss and death. Thorough arterial supply monitoring by Doppler ultrasonography and urgent endovascular arterial flow restoration may salvage both graft and the recipient.

Real-world management of maple syrup urine disease (MSUD) metabolic decompensations with branched chain amino acid-free formulas in France and Germany: A retrospective observational study

Maple syrup urine disease (MSUD) is a rare inborn metabolic disorder, managed with a strict protein-restricted diet. At any time or age patients may still experience metabolic decompensations, requiring administration of branched chain amino acid (BCAA)-free formula to reduce leucine levels. This retrospective observational study of 126 decompensation episodes from 54 MSUD patients treated at five centers in France and Germany from 2010 to 2016, describes episodes and outcomes for patients stratified into groups who received enteral/oral or intravenous (IV) BCAA-free formula, and by pediatric or adult age categories. IV administration of BCAA-free formula was required in cases of gastric intolerance (33%), refusal to undergo nasogastric tubing (31%), "emergency" (14%) or coma patients (8%), and as prophylaxis before surgery (6%). Overall, mean duration of hospitalization was 6.6 days with oral/enteral BCAA-free formula and 5.4 days with IV formula. Leucine levels at discharge decreased by a mean of 548.5 μmol/L (69.3%) in the oral/enteral group and 657.2 μmol/L (71.3%) in the IV group. In the pediatric subgroup, there were no marked differences between administration groups on any outcome. In the adult subgroup, mean time to episode resolution was 15.8 days in the oral/enteral group and 7.7 days in the IV group (P = .008); mean duration of hospitalization was 6 days in the oral/enteral group and 4.6 days in the IV group (P = NS). Overall, seven serious adverse events in two patients were reported, of which only nausea and vomiting were treatment related.

Sarcopenia in Children With End-Stage Liver Disease on the Transplant Waiting List

Sarcopenia predicts morbidity and mortality in adults with end-stage liver disease (ESLD) and is determined by total psoas muscle area (tPMA) measurement from computed tomography (CT) imaging. Recently developed pediatric age- and sex-specific tPMA growth curves provide the opportunity to ascertain prevalence and impact of sarcopenia in children awaiting liver transplantation (LT). This retrospective single-center study evaluated sarcopenia in children between 1 and 16 years with ESLD and a clinically indicated abdominal CT less than 3 months before first isolated LT. Sarcopenia was defined as tPMA z score less than -2 measured at the intervertebral L4-5 level. Patient demographic, biochemical, and outcome data were recorded. tPMA was compared with other measures of nutritional status using univariate and multivariate logistic analyses. Outcome measures included 1-year morbidity events and mortality after LT. CT images from 25 (64% female) children with median age of 5.50 (interquartile range [IQR], 3.75-11.33) years were reviewed. Ten children (40%) had a tPMA z score less than -2. Sarcopenia was associated with lower z scores for weight (odds ratio [OR], 0.38; P = 0.02), height (OR, 0.32; P = 0.03), and nutritional support before LT (OR, 12.93; P = 0.01). Sarcopenic children had a longer duration of pediatric intensive care unit (PICU) stay (3.50 [IQR, 3.00-6.00] versus 2.00 [IQR, 2.00-3.50] days; P = 0.03). Sarcopenia was prevalent in 40% of children with ESLD awaiting LT, and lower tPMA z score was associated with deficient anthropometrics and need for nutritional support before LT. Post-LT PICU duration was increased in children with sarcopenia, reflecting adverse outcomes associated with muscle loss. Further studies are needed to elucidate the underlying mechanisms of sarcopenia in children with ESLD.

Post-operative heparin reduces early venous thrombotic complications after orthotopic paediatric liver transplantation

BACKGROUND

Despite significant improvements in surgical techniques and medical care, thrombotic complications still represent the primary cause of early graft failure and re-transplantation following paediatric liver transplantation. There is still no standardized approach for thrombosis prevention.

MATERIALS AND METHODS

The study aimed to evaluate the effectiveness of early intravenous unfractionated heparin started 12 hours postoperatively at 10 UI/kg per hour and used a retrospective "before and after" design to compare the incidence of early thrombotic complications prior to (2002-2010) and after (2011-2016) the introduction of heparin in our institute.

RESULTS

From 2002 to 2016, 479 paediatric patients received liver transplantation in our institution with an overall survival rate over one year of 0.91 (95% CI: 0.87-0.94). Of 365 eligible patients, 244 did not receive heparin while 121 did receive heparin. We reported a lower incidence of venous thrombosis (VT) in the group treated with heparin: 2.5% (3/121) vs 7.9% (19/244) (p=0.038). All clinical and laboratory variables considered potential risk factors for VT were studied. By multivariate stepwise Cox proportional hazards models, heparin prophylaxis resulted significantly associated to a reduction in VT (HR=0.29 [95% CI: 0.08-0.97], p=0.045), while age <1 year was found to be an independent risk factor for VT (HR=2.62 [95% CI: 1.11-6.21]; p=0.028).

DISCUSSION

Early postoperative heparin could be considered a valid and safe strategy to prevent early VT after paediatric liver transplantation without a concomitant increase in bleeding. A future randomised control trial is mandatory in order to strengthen this conclusion.

Undiagnosed liver diseases

The landscape of chronic liver disease has drastically changed over the past 20 years, largely due to advances in antiviral therapy and the rise of metabolic syndrome and associated non-alcoholic fatty liver disease (NAFLD). Despite advances in the diagnosis and treatment of a variety of liver diseases, the burden of chronic liver disease is increasing worldwide. The first step to addressing any disease is accurate diagnosis. Here, we discuss liver diseases that remain undiagnosed, either because they are difficult to diagnose or due to hepatic manifestations of an unrecognized systemic disease. Additionally, their underlying etiology may remain unknown or they represent previously uncharacterized and therefore novel liver diseases. Our goal is to provide a framework for approaching undiagnosed liver diseases which elude standard hepatic diagnostic work-up and whose patterns of disease are often overlooked.

Perioperative blood transfusion decreases long-term survival in pediatric living donor liver transplantation

BACKGROUND

The impact of perioperative blood transfusion on short- and long-term outcomes in pediatric living donor liver transplantation (PLDLT) must still be ascertained, mainly among young children. Clinical and surgical postoperative complications related to perioperative blood transfusion are well described up to three months after adult liver transplantation.

AIM

To determine whether transfusion is associated with early and late postoperative complications and mortality in small patients undergoing PLDLT.

METHODS

We evaluated the effects of perioperative transfusion on postoperative complications in recipients up to 20 kg of body weight, submitted to PLDLT. A total of 240 patients were retrospectively allocated into two groups according to postoperative complications: Minor complications (n = 109) and major complications (n = 131). Multiple logistic regression analysis identified the volume of perioperative packed red blood cells (RBC) transfusion as the only independent risk factor for major postoperative complications. The receiver operating characteristic curve was drawn to identify the optimal volume of the perioperative RBC transfusion related to the presence of major postoperative complications, defining a cutoff point of 27.5 mL/kg. Subsequently, patients were reallocated to a low-volume transfusion group (LTr; n = 103, RBC ≤ 27.5 mL/kg) and a high-volume transfusion group (HTr; n = 137, RBC > 27.5 mL/kg) so that the outcome could be analyzed.

RESULTS

High-volume transfusion was associated with an increased number of major complications and mortality during hospitalization up to a 10-year follow-up period. During a short-term period, the HTr showed an increase in major infectious, cardiovascular, respiratory, and bleeding complications, with a decrease in rejection complications compared to the LTr. Over a long-term period, the HTr showed an increase in major infectious, cardiovascular, respiratory, and minor neoplastic complications, with a decrease in rejection complications. Additionally, Cox hazard regression found that high-volume RBC transfusion increased the mortality risk by 3.031-fold compared to low-volume transfusion. The Kaplan-Meier survival curves of the studied groups were compared using log-rank tests and the analysis showed significantly decreased graft survival, but with no impact in patient survival related to major complications. On the other hand, there was a significant decrease in both graft and patient survival, with high-volume RBC transfusion.

CONCLUSION

Transfusion of RBC volume higher than 27.5 mL/kg during the perioperative period is associated with a significant increase in short- and long-term postoperative morbidity and mortality after PLDLT.

Outcomes following liver transplantation in young infants: Data from the SPLIT registry

Liver transplantation (LT) in young patients is being performed with greater frequency. We hypothesized that objective analysis of pre-, intra-, and postoperative events would help understand contributors to successful outcomes and guide transplant decision processes. We queried SPLIT registry for pediatric transplants between 2011 and 2018. Outcomes were compared for age groups: 0-<3, 3-<6, 6-<12 months, and 1-<3 years (Groups A, B, C, D respectively) and by weight categories: <5, 5-10, >10 kg; 1033 patients were available for analysis. Cholestatic disease and fulminant failure were highest in group A and those <5 kg; and biliary atresia in group C (72.8%). Group A had significantly higher life support dependence (34.6%; P < .001), listing as United Network for Organ Sharing status 1a/1b (70.4%; P < .001), and shortest wait times (P < .001). The median (interquartile range) for international normalized ratio and bilirubin were highest in group A (3.0 [2.1-3.9] and 16.7 [6.8-29.7] mg/dL) and those <5 kg (2.6 [1.8-3.4] and 13.5 [3.0-28.4] mg/dL). A pediatric end -stage liver disease score ≥40, postoperative hospital stays, rejection, and nonanastomotic biliary strictures were highest in group A with lowest survival at 93.1%. Infants 0 to <3 months and those <5 kg need more intensive care with lower survival and higher complications. Importantly, potential LT before reaching status 1a/1b and aggressive postoperative management may positively influence their outcomes.

Catastrophic Brain Aspergillosis after Liver Transplantation

Background. Liver transplantation has many complications. Because of receiving immunosuppressive regimens, infectious complications in these patients may have fatal results. Aspergillosis in solid organ recipients is one of the most common fungal infections that usually occur 1 month after transplantation. Aspergillus infection mainly involves the lungs. Although the central nervous system may get involved due to hematogenous spreading from lungs, isolated central nervous system involvement is rarely reported. Case Presentation. The patient was an 8-year-old boy, with a case of Wilson disease, who underwent liver transplantation due to acute fulminant hepatic failure. Four days after the surgery, he was affected by fever, agitation, loss of consciousness, hemiparesis, and focal seizure. Brain MRI showed abscess formation, whereas chest X-ray was normal. Intravenous antibiotics were initiated but the patient's condition was not improving; therefore, surgical drainage of the abscess was performed. The pathological investigation was compatible with aspergillosis. Antifungal therapy with voriconazole was administrated. His symptoms were resolved but unfortunately, brain lesions caused persistent vegetative state. Discussion. Aspergillus is a ubiquitous organism that mainly occurs in immunocompromised patients. Aspergillosis could be prevented by environmental modification such as installing high-efficiency particulate air filters. Chemoprevention with triazoles, echinocandins, and polyenes is also effective. Voriconazole is the drug of choice for aspergillosis treatment. Although voriconazole is a highly effective antifungal drug, cerebral aspergillosis is often fatal.

Survival and Complication of Liver Transplantation in Infants: A Systematic Review and Meta-Analysis

Background: Modern surgical techniques and scientific advancements have made liver transplant (LT) in infants feasible. However, there are only a small number of studies examining the short- as well as long-term outcomes of LT in this vulnerable subset of children. Methods: Comprehensive searches were done systematically through the PubMed, Scopus, and Google scholar databases. Studies that were retrospective record based or adopted a cohort approach and reported either patient survival rates or graft survival rates or complications of LT in infants were included in the meta-analysis. Statistical analysis was done using STATA version 13.0. Results: A total of 22 studies were included in the meta-analysis. The overall pooled patient survival rate at 1 year, >1-5 years, and >5 years post-transplantation was 85% (95% CI: 78--92%), 71% (95% CI: 59-83%), and 80% (95% CI: 69-91%), respectively. The overall pooled graft survival rate at 1 year, >1-5 years, and >5 years post-transplantation was 72% (95% CI: 68-76%), 62% (95% CI: 46-78%), and 71% (95% CI: 56-86%), respectively. The overall pooled rate for vascular complications, need for re-transplantation, biliary complications, and infection/sepsis was 12% (95% CI: 10-15%), 16% (95% CI: 12-20%), 15% (95% CI: 9-21%), and 50% (95% CI: 38-61%), respectively. Conclusion: The current meta-analysis showed modest patient and graft survival rates for infant liver transplantation. However, the complication rates related to infection/sepsis were high. More comprehensive evidence is required from studies with larger sample sizes and a longer duration of follow-up.

Association Between Serum Lactate and Unsatisfactory Outcomes in Critically Ill Children in the Immediate Post-operative Period of Liver Transplantation

OBJECTIVES

Serum lactate is a useful biomarker of tissue perfusion in critically ill patients. We evaluated the behavior of serum lactate in children in the pediatric intensive care unit (PICU) immediately after liver transplantation and its association with surgical complications, graft dysfunction and 90-day mortality.

MATERIALS AND METHODS

A prospective observational study carried out between November 2009 and December 2019. Multidisciplinary PICU at the University Children's Hospital, Fundación Cardioinfantil-IC, Bogotá, Colombia.

MEASUREMENTS AND MAIN RESULTS

Patients between 1 month and 18 years of age who were in the immediate post-operative period following living-donor or cadaveric liver transplantation were included. A total of 145 patients with a median age of 14 months (IQR 8-60) met the inclusion criteria. Biliary atresia was the main diagnosis in 56.5% of the cases. A serum lactate level > 3.0 mmol/L on admission to the PICU was associated with biliary complications (AUC 0.73 95% CI 0.54-0.93; p = 0.05) and mortality (AUC 0.72 95% CI 0.63-0.8; p = 0.01). A lactate level > 2 mmol/L after 6 h in the PICU was associated with mortality (AUC 0.70 95% CI 0.54-0.83; p = 0.02). Higher lactate levels and lack of clearance were associated with the presence of tardus et parvus waveforms (p = 0.001) on liver Doppler, primary dysfunction (p < 0.001), arterial thrombosis (p < 0.001) and neurological complications (p = 0.04). There was an inverse correlation between admission lactate and the volume of fluids administered during surgery (rho = 0.36; p < 0.001). A total procedure time > 350 min, along with a vasopressor score > 7 and elevated lactate, were associated with worse outcomes (p < 0.001).

CONCLUSIONS

In post-operative pediatric liver transplant patients, the level of serum lactate is associated with post-operative surgical complications and mortality.

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.

What is the long-term outlook for young people following liver transplant? A single-centre retrospective analysis of physical and psychosocial outcomes

LT is a successful treatment for end-stage liver disease. The long-term outcome of patients transplanted in childhood has not previously been widely reported. This project assessed the long-term impact of transplantation in patients surviving >15 years. Retrospective data on growth, end-organ damage and psychosocial development were collected in young people transplanted from 1985 to 2000 in a single centre. Clinical notes were reviewed, and patients interviewed at clinic follow-up. 224 patients were transplanted between 1985 and 2000. 143 recipients (63.8%) survived >15 years with a median survival of 19.52 years. The majority were well, and only 10% had abnormal graft function (biochemical/synthetic), the main cause of which was chronic hepatitis (6%). Renal dysfunction and the necessity for renal transplant were identified in 32.8%, of whom 16.7% of patients had a cGFR <70 mL/min/1.73 m² and 6% of patients had either undergone or awaiting renal transplant. This cohort was healthier than the average age-matched UK population in terms of body mass index (9% obese), smoking and alcohol consumption. 92% of patients had completed or were in education (93/123 had completed education and 20/123 remained in school). 63.7% of patients had been transitioned into adult services, and 46.3% of these patients were employed. 67.5% were in a relationship, one patient was divorced, and 10.6% of patients had one or more children. 11 patients had symptoms that corresponded to a DSM IV diagnosis of depression. Four patients had anorexia nervosa. Developmental delay was identified in 9 out of 99 patients. The development of malignancy, including PTLD, occurred in 10/143 (7%) patients at a median time post-transplant of 2.76 years (range 0.76-9.06 years). Epstein-Barr infection was implicated in 75% of these malignancies. We conclude the long-term outcome of LT in childhood is good with 63.8% surviving into adulthood and over 60% transferring into adult services. Graft dysfunction and end organ damage are minimal. Our cohort is healthier than the general population, and the majority have completed education, sought employment and formed relationships with peers, contributing well to society.

Fulminant hepatic failure: A rare and devastating manifestation of Coronavirus disease 2019 in an 11-year-old boy

Although several typical manifestation of novel coronavirus disease 2019 (COVID-19) including respiratory symptoms, weakness, fever, and fatigue have been reported, some rare and novel manifestations have also been observed, particularly in children. We report a pediatric case of fulminant hepatic failure associated with COVID-19. Although the patient was treated for acute fulminant hepatic failure in the context of COVID-19, he died following the progression of the disease to stage 4 hepatic failure with encephalopathy and brain death.

Oral health-related quality of life among pediatric liver transplant candidates

To assess the impact of oral conditions on the oral health-related quality of life (OHRQoL) of pediatric liver transplant candidates. This cross-sectional study included 60 children aged 13 to 48 months who were liver transplant candidates that attended the AC Camargo Cancer Center, São Paulo, Brazil. On the day of oral examinations, the children's mothers were invited to answer two questionnaires; one related to children's OHRQoL using the B-ECOHIS and another related to socioeconomic/demographic characteristics. Thereafter, a single, adequately trained dentist carried out children's oral examinations for gingival inflammation (Silness-Löe index), dental plaque (Green-Vermillion Simplified index), dental caries (dmft index), developmental defects of enamel (DDE index), tooth discoloration, oral mucosal/lip alterations. The data collected also included socioeconomic/demographic characteristics and liver disease. The adjusted Poisson regression model was used to associate children's socioeconomic/demographic characteristics and clinical conditions to the outcome. The adjusted regression model showed that children with untreated caries lesions (RR = 3.35, p < 0.0001) and tooth discoloration (RR = 1.74, p = 0.04) had poorer total B-ECOHIS scores. Dental discoloration and untreated caries lesions had a negative impact on the OHRQoL in pediatric liver transplant candidates.

Hepatic Artery Thrombosis in Liver Transplantation in Adult Recipients Using Pediatric Deceased Donors

INTRODUCTION

Routinely, pediatric donor (PD) grafts are allocated to pediatric liver transplantation (LT) recipients; however, occasionally they can be allocated for adult recipients (ARs). Some authors reported decreased patient/graft survival and higher vascular complications, such as hepatic artery thrombosis (HAT), in LT in ARs using PDs.

METHODS

It is a retrospective study enrolling 1202 ARs undergoing LT using whole liver grafts during the period of January 2002 to April 2019. The patients were categorized according to donor age in 2 groups: PDs and adult donors (ADs). The variables were collected from the database including the graft to recipient weight ratio (GWRW) and the incidence of HAT and graft primary nonfunction (PNF).

RESULTS

The AD group had 1152 patients, and the PD group had 50 patients. PNF occurred in 68 (5.66%) patients, and the distribution between the 2 groups were similar: 65 (5.64%) in the AD group, and 3 (6%) in the PD group (P = .915). HAT was diagnosed in 30 (2.6%) patients in the AD group and in 6 (12%) patients in the PD group. HAT was significantly higher in the PD group (P = .001). In the PD group, the GWRWs among patients diagnosed with HAT were similar (P = .152).

CONCLUSION

HAT is higher in PDs, although it is a viable alternative with satisfactory results. Serial Doppler in the first week and early introduction of platelet antiaggregants and/or anticoagulants may be beneficial, albeit it is not clear if it could reduce the incidence of HAT.

Lifestyle Modification Leads to Spatially Variable Reduction in Hepatic Steatosis in Potential Living Liver Donors

The spatial variability of hepatic fat reduction in potential living liver donors with hepatic steatosis (HS) who undergo lifestyle modification has not been investigated. Here, we aimed to examine the intrasegmental and intersegmental variability of changes in liver attenuation on computed tomography (CT) in potential living liver donors with HS after diet modification and exercise. A total of 87 living liver donor candidates (30.5 ± 7.0 years; 74 males) with biopsy-proven macrovesicular fat (MaF) ≥10% were included. All underwent diet modification and exercise to improve HS, baseline and follow-up unenhanced CT scans, and liver biopsies. Attenuation and its variability (mean and standard deviation, respectively, in Hounsfield units) in segmental, lobar, superficial, deep, and whole areas of the liver were measured across 32 different regions of interest on both baseline and follow-up CT. At baseline, the right lobe and superficial areas of liver showed significantly lower and more variable attenuation than left lobe and deep areas. Greater variability was noted in patients with more severe HS. Mean interval changes in liver attenuation and variability before and after diet modification and exercise were 13.7 (range, -10.6 to 46.2) and 4.7 (1.6-10.6), respectively. The mean interval change in liver attenuation was significantly higher in the right lobe than in the left (14.7 versus 12.7; P < 0.001), and in superficial areas than in deep areas (14.0 versus 13.4; P = 0.02). Greater variability and larger interval changes in liver attenuation were noted in those who responded (≥20% decrease in MaF) to diet modification and exercise than in those who did not. In conclusion, potential living liver donors with HS show significant intrasegmental and intersegmental variability in hepatic fat reduction on CT before and after diet modification and exercise.

Tubercular hemoptysis in a young liver transplanted patient: Case report

RATIONALE

Liver transplanted patients have excellent survival rates, but infectious complications are a major cause of morbidity and mortality. Diagnosis and treatment of tuberculosis (TB) in liver recipients are very challenging. Specific recommendations for anti-TB treatment in liver transplanted patients are lacking.

PATIENT CONCERNS AND DIAGNOSIS

A 22-year-old male liver transplanted patient because of biliary atresia showed unexpected acute hemoptysis while he was on immunosuppressive therapy with tacrolimus and mycophenolate mofetil. Computed tomography (CT) identified a pulmonary arteriovenous malformation (PAVM) successfully treated with endovascular embolization. A post-embolization thoracic CT revealed pulmonary cavitation and miliary pattern suggesting pulmonary TB causing PAVM. TB diagnosis was confirmed by microbiological assays and genetic amplification techniques.

INTERVENTION

Anti-TB 4-drug regimen was started. Following the beginning of treatment, liver enzymes increased. In order to clarify if liver cytolysis was due to hepatotoxicity or hepatic rejection linked to the reduction of immunosuppression or a worsening of pre-existing graft hepatitis, a liver biopsy was performed. A mild graft rejection was found so that tacrolimus doses were increased despite the risk of tubercular dissemination.

OUTCOME

The patient completed anti-TB therapy in 8 months with resolution of TB disease and stable liver disease.

LESSONS

TB management in liver transplanted patients is challenging and needs to be individualized especially if chronic graft hepatitis is present.

Pathobiology of inherited biliary diseases: a roadmap to understand acquired liver diseases

Bile duct epithelial cells, also known as cholangiocytes, regulate the composition of bile and its flow. Acquired, congenital and genetic dysfunctions in these cells give rise to a set of diverse and complex diseases, often of unknown aetiology, called cholangiopathies. New knowledge has been steadily acquired about genetic and congenital cholangiopathies, and this has led to a better understanding of the mechanisms of acquired cholangiopathies. This Review focuses on findings from studies on Alagille syndrome, polycystic liver diseases, fibropolycystic liver diseases (Caroli disease and congenital hepatic fibrosis) and cystic fibrosis-related liver disease. In particular, knowledge on the role of Notch signalling in biliary repair and tubulogenesis has been advanced by work on Alagille syndrome, and investigations in polycystic liver diseases have highlighted the role of primary cilia in biliary pathophysiology and the concept of biliary angiogenic signalling and its role in cyst growth and biliary repair. In fibropolycystic liver disease, research has shown that loss of fibrocystin generates a signalling cascade that increases β-catenin signalling, activates the NOD-, LRR- and pyrin domain-containing 3 inflammasome, and promotes production of IL-1β and other chemokines that attract macrophages and orchestrate the process of pericystic and portal fibrosis, which are the main mechanisms of progression in cholangiopathies. In cystic fibrosis-related liver disease, lack of cystic fibrosis transmembrane conductance regulator increases the sensitivity of epithelial Toll-like receptor 4 that sustains the secretion of nuclear factor-κB-dependent cytokines and peribiliary inflammation in response to gut-derived products, providing a model for primary sclerosing cholangitis. These signalling mechanisms may be targeted therapeutically and they offer a possibility for the development of novel treatments for acquired cholangiopathies.

An Overview of Liver Transplant Pathology: Data from a Tertiary Referral Centre in Western India

INTRODUCTION AND AIM

1. Study of liver explants - Etiologic types of end-stage chronic liver disease (ESCLD) and acute liver failure (ALF) in adults and children. 2. Assessment of donor steatosis and incidental granulomas. 3. Post-transplant liver biopsies.

MATERIAL AND METHODS

Specimens of 180 explant hepatectomies, 173 donor wedge and 30 core liver biopsies, and 58 post transplant liver biopsies received in our department from April 2013 to March 2017.

RESULTS

1. Most common causes of ESCLD in adults were: alcohol related (30.32%), hepatitis virus related (18.71%) and non-alcoholic steatohepatitis related (18.06%); and in children ≤ 12 years were: biliary atresia (27.27%), autoimmune disease (18.18%) and Wilson's disease (18.18%). Most common causes of ALF in adults and children were anti-tubercular therapy induced and idiopathic respectively. 2. Prevalence rate of moderate steatosis (between 30-60%) was 4.28%. Incidental granulomas were seen in 5 cases. 3. Most common diagnoses of post-transplant biopsies in adults included acute cellular rejection (ACR) (36.17%), recurrence of viral disease (8.51%) and moderate non-specific portal triaditis (8.51%). Among children ≤ 12 years, most common diagnoses included unremarkable liver parenchyma, ACR and ischemia/reperfusion injury.

CONCLUSION

1. Alcohol- and hepatitis- virus related ESCLD, and biliary atresia are leading indications for liver transplantation in adults and children respectively. 2. Prevalence of 4.28% of moderate steatosis, is much lower than that documented in western literature. Only 5 cases of incidental granulomas is unexpectedly low in a country endemic for tuberculosis. 3. Most common diagnoses of post-transplant liver biopsies in adults has been acute rejection, which is similar to the findings from much larger published series.