Overview of pediatric liver transplantation

Liver transplantation is a successful and useful therapy for children with chronic or end-stage liver disease and those with a variety of extrahepatic metabolic diseases that can be corrected by liver replacement. Major developments in medical management, donor availability and procurement, operative techniques, and post-operative management all contributed to the dramatic improvement in outcome and growth of liver transplantation from its inception in 1963 [1,7,21]. The excellent long-term outcomes that have been achieved are the product of the coordinated efforts of liver transplant surgeons, specialists in pediatric hepatology and other medical areas, nurses, local practitioners, and the patients and their families. Future advances in transplant immunobiology, organ availability and infection control are likely to lead to still greater improvements in short and long-term outcome [34].     

Recent advances in pediatric liver transplantation

Pediatric liver transplantation has matured into a wellestablished, highly successful treatment for advanced pediatric liver disease. Recent 1-year success rates range from 85% to 95%. This unprecedented achievement is the result of careful selection criteria and optimal timing of transplantation, technical advances in surgical technique, and improved treatment following transplant. This report highlights many recent published findings representing advances that have led to current successful approaches.     

Current status of pediatric liver transplantation

Increased survival for young liver transplant recipients has greatly improved. Increasing success has led to broader indications, thereby increasing the number of potential recipients. Pediatric liver centers are developing new strategies to cope with the ever-increasing demands for suitable size appropriate grafts. UNOS is in the process of updating guidelines to regulate the sharing of organs which become available from new surgical techniques. In the future, alternative therapies, such as artificial liver assist devices and techniques of cellular transplantation and genetic modification of hepatocytes, may decrease the number of children who die while waiting for a suitable organ or even obviate the need for the liver transplantation.     

Current developments in pediatric liver transplantation

In 1953, the pioneer of human orthotopic liver transplantation(LT), Thomas E Starzl, was the first to attempt an orthotopic liver transplant into a 3 years old patient suffering from biliary atresia. Thus, the first LT in humans was attempted in a disease, which, up until today, remains the main indication for pediatric LT(p LT). During the last sixty years, refinements in diagnostics and surgical technique, the introduction of new immunosuppressive medications and improvements in perioperative pediatric care have established LT as routine procedure for childhood acute and chronic liver failure as well as inherited liver diseases. In contrast to adult recipients, p LT differs greatly in indications for LT, allocation practice, surgical technique, immunosuppression and postoperative life-long aftercare. Many aspects are focus of ongoing preclinical and clinical research. The present review gives an overview of current developments and the clinical outcome of p LT, with a focus on alternatives to full-size deceased-donor organ transplantation.     

Adult to pediatric living donor liver transplantation for portal cavernoma

Aim:  Portal cavernoma (PC) is an important cause of non-cirrhotic portal hypertension with severe complications, such as variceal hemorrhage in pediatric patients. With the development of new surgical techniques, living donor liver transplantation (LDLT) has recently been recognized as a viable but challenging treatment option for PC. The purpose of the present study was to summarize the efficacy of LDLT in PC patients and to carry out a follow-up study of pediatric recipients.
Methods:  The primary indication for LDLT in our research was PC with severe variceal bleeding and liver function decompensation. Three patients were diagnosed with PC following evaluation with computed tomography angiography and abdominal color Doppler ultrasonography (CDU).
Results:  Various surgical techniques, including jump bypass grafting for portal vein anastomosis, were carried out according to the range and degree of cavernous transformation within the splenic vein and superior mesenteric vein. Postoperative CDU confirmed the early integrity of the portal vein (PV) in each patient. PV rethrombosis occurred in one patient 7 days after LDLT, despite anticoagulation therapy with coumadin. Two of the three patients had no further episodes of variceal hemorrhage during the 2-year follow-up period.
Conclusions:  The present study is the first report of the successful use of LDLT to treat pediatric PC patients. We conclude that LDLT is effective for the majority of pediatric patients with PC.     

儿童急性肝衰竭的肝移植治疗

儿童急性肝衰竭(PALF)是一种罕见的综合征,致死率高。肝移植仍然是目前PALF唯一疗效肯定的治疗方法。近年来,我国儿童肝移植技术日趋成熟,已显著改善PALF预后。但PALF进行肝移植仍存在许多问题,充分讨论PALF患儿行肝移植术术前、术中和术后存在的客观问题,将进一步改善PALF患儿的整体预后。     

Progressive histological damage in liver allografts following pediatric liver transplantation

The long-term histological outcome after pediatric liver transplantation (OLT) is not yet fully understood. De novo autoimmune hepatitis, consisting of histological chronic hepatitis associated with autoantibody formation and allograft dysfunction, is increasingly recognized as an important complication of liver transplantation, particularly in the pediatric population. In this study, 158 asymptomatic children with 5-year graft survival underwent protocol liver biopsies (113, 135, and 64 at 1, 5, and 10 years after OLT, respectively). Histological changes we re correlated with dinical,biochemical, and serological findings. All patients received cydosporine A as primary immunosuppression with withdrawal of corticosteroids at 3 months post OLT. Normal or near-normal histology was reported in 77 of 113 (68%), 61 of 135 (45%), and 20 of 64 (31%) at 1, 5, and 10 years, respectively. The commonest histological abnormality was chronic hepatitis (CH), the incidence of which increased with time [25/113 (22%), 58/135 (43%), and 41/64 (64%) at 1, 5, and 10 years, respectively) (P < .0001)]. The incidence of fibrosis associatedwith CH increasedwith time [13/25 (52%), 47/58 (81%), and 37/41 (91%) at 1, 5, and 10 years, respectively) (P < .0001)]. The severity of fibrosis associated with CH also increased with time, such that by 10 years 15% had progressed to cirrhosis. Aspartate aminotransfemse (AST) levels were slightly elevated in children with CH (median levels 52 IU/L, 63 IU/L, and 48 IU/L at 1, 5, and 10 years, respectively), but this did not reach statistical significance compared with those with normal histology. On multivariate analysis, the only factor predictive of chronic hepatitis was autoantibody positivity (present in 13% and 10% of children with normal biopsies at 5 and 10 years, respectively, and 72% and 80% of those with CH at 5 and 10 years, respectively) (P < .0001). Four children with CH and autoantibodies, who also had raised immunoglobulin G (IgG) levels and AST greater than 1.5 x normal fulfilled the diagnostic criteria for de novo autoimmune hepatitis (AIH). Another two were found to be hepatitis C positive. No definite cause for CH could be identified in the other cases. In condusion, chronic hepatitis is a common finding in children after liver transplantation and is associated with a high risk of developing progressive fibrosis, leading to cirrhosis. Standard liver biochemical tests cannot be relied on either in the diagnosis or in the monitoring of progress of chronic allograft hepatitis. In contrast, the presence ofautoantibodies is strongly associated with the presence of CH. The cause of chronic hepatitis in transplanted allografts is uncertain but may be immune mediated, representing a hepatitic form of chronic rejection.     

Endotipsitis as an indication for pediatric liver transplantation

Endotipsitis is a rare but severe complication of transjugular intrahepatic portosystemic shunt (TIPS), a device widely used to treat portal hypertension in adults, but sparsely used in children. We report a case of endotipsitis in a 3‐year‐old child affected of biliary atresia. She underwent a Kasai procedure at 3 months of age but, although the bile flow was restored, she presented upper gastrointestinal bleeding due to portal hypertension 1.5 years later. A TIPS was placed in order to control the hemorrhage. A year after TIPS placement, she started presenting repeated episodes of cholangitis. Blood cultures were positive to Enterobacter cloacae. Even with long antibiotic courses, adjusted to blood cultures, infectious signs were observed after antibiotic withdrawal. Device infection was demonstrated through Positron emission tomography‐Computed tomography scan. The patient was listed for liver transplantation, and intravenous antibiotic treatment was maintained until stent removal during the liver transplant 8 months later. No infectious complications were demonstrated after the surgery. To the best of our knowledge, this is the first case report of endotipsitis described in a pediatric patient.     

Current status and outcome of pediatric liver transplantation

In this article the diagnostic indications for hepatic transplantation are addressed in detail. The outcome of liver transplantation is also examined, including the impact of the following factors on survival: age and weight at transplantation, type of liver disease, and size of liver allograft, including living related transplantation. Morbidity and quality of life after transplantation are other aspects reviewed in this chapter.     

Herpes simplex virus hepatitis after pediatric liver transplantation

T. Hori, Y. Ogura, S. Okamoto, A. Nakajima, K. Kami, J. Iwasaki, Y. Yonekawa, K. Ogawa, F. Oike, Y. Takada, H. Egawa, J.H. Nguyen, S. Uemoto. Herpes simplex virus hepatitis after pediatric liver transplantation
Transpl Infect Dis 2010: 12: 353–357. All rights reserved Abstract: Herpes simplex virus (HSV) hepatitis has a fatal impact on the outcome of organ transplanted recipients. Here, we present a thought‐provoking case of HSV hepatitis in a high‐risk recipient after living‐related liver transplantation (LRLT). A 1‐month‐old female newborn infant was affected by HSV encephalitis. Fulminant hepatic failure (FHF) of unknown etiology occurred suddenly at 4.4 years of age. Viral infections were ruled out as the cause of FHF. Intensive care including plasma exchange (PE) was started, and the preoperative treatments for ABO incompatibility were performed. Thereafter, LRLT was performed emergently. Although strong immunosuppression for ABO incompatibility was continued after LRLT, antibody‐mediated rejection (AMR) occurred on postoperative day (POD) 4. PE was repeated and improvements were obtained. However, liver dysfunction appeared on POD 8. Histopathological findings of liver needle biopsy clearly revealed HSV hepatitis, although the results of HSV DNA and antibody titer in blood sample did not clearly indicate HSV infection. On POD 21, thrombotic microangiopathy (TMA) occurred and the plasma and immunoglobulin were replenished. Our pediatric recipient recovered successfully from AMR, HSV hepatitis, TMA, and repeated sepsis. We conclude that well considered therapy based on the real‐time detection of HSV hepatitis is indispensable for the further improvements of outcome in HSV hepatitis after LRLT.     

Coagulopathy and transfusion therapy in pediatric liver transplantation

Bleeding and coagulopathy are critical issues complicating pediatric liver transplantation and contributing to morbidity and mortality in the cirrhotic child. The complexity of coagulopathy in the pediatric patient is illustrated by the interaction between three basic models. The first model, developmental hemostasis, demonstrates how a different balance between pro- and anticoagulation factors leads to a normal hemostatic capacity in the pediatric patient at various ages. The second, the cell based model of coagulation, takes into account the interaction between plasma proteins and cells. In the last, the concept of rebalanced coagulation highlights how the reduction of both pro- and anticoagulation factors leads to a normal, although unstable, coagulation profile. This new concept has led to the development of novel techniques used to analyze the coagulation capacity of whole blood for all patients. For example, viscoelastic methodologies are increasingly used on adult patients to test hemostatic capacity and to guide transfusion protocols. However, results are often confounding or have limited impact on morbidity and mortality. Moreover, data from pediatric patients remain inadequate. In addition, several interventions have been proposed to limit blood loss during transplantation, including the use of antifibrinolytic drugs and surgical techniques, such as the piggyback and lowering the central venous pressure during the hepatic dissection phase. The rationale for the use of these interventions is quite solid and has led to their incorporation into clinical practice; yet few of them have been rigorously tested in adults, let alone in children. Finally, the postoperative period in pediatric cohorts of patients has been characterized by an enhanced risk of hepatic vessel thrombosis. Thrombosis in fact remains the primary cause of early graft failure and re-transplantation within the first 30 d following surgery, and it occurs despite prolongation of standard coagulation assays. Data, however, are currently lacking regarding the use of anti-aggregation/anticoagulation therapies and how to best monitor for thrombosis in the early postoperative period in pediatric patients. Therefore, further studies are necessary to elucidate the interaction between the development of the coagulation system and cirrhosis in children. Moreover, strategies to optimize blood transfusion and anticoagulation must be tested specifically in pediatric patients. In conclusion, data from the adult world can be translated with difficulty into the pediatric field as indication for transplantation, baseline pathologies and levels of pro- and anticoagulation factors are not comparable between the two populations.     

Brucella infection with pancytopenia after pediatric liver transplantation

Brucellosis is considered the most widespread zoonosis in the world. It has been reported that the prevalence of seropositivity among the Turkish population varies from 3% to 14%. We present a case of brucellosis after pediatric liver transplantation. A 15‐year‐old boy with the diagnosis of neuro Wilson's disease underwent deceased‐donor liver transplantation. The postoperative immunosuppressive protocol consisted of steroids and tacrolimus. Two months after the operation the patient experienced fever to 40°C. The patient complained of poor appetite, headache, and diarrhea. He had had pancytopenia. Despite administration of appropriate antibiotics, antiviral and antifungal agents, fever persisted for > 1 month. Multiple blood, urine, stool, and sputum cultures were negative. Bone marrow aspirate revealed hypocellularity. Liver biopsy was performed, but rejection was not observed on biopsy specimen. Brucella serology was positive and Brucella agglutination titer was 1:320. Bone marrow culture was positive for Brucella but blood culture was negative. The patient was then treated with oral doxycyline and rifampin for 8 weeks. No previous case report about Brucella infection after liver transplantation has appeared in the literature, to our knowledge; our case is presented as the first. Bone marrow hypoplasia is a rare feature of Brucella infection. Our patient with brucellosis and pancytopenia had had hypocellular bone marrow. The clinical and hematologic findings resolved with treatment of the infection. Brucella infection should be suspected in liver transplanted recipients with fever of unknown origin, especially in a recipient who has lived in an endemic area. Brucella also should be considered as a possible diagnosis in patients with pancytopenia.     

Liver transplantation for pediatric inherited metabolic liver diseases

Liver transplantation(LT) remains the gold standard treatment for end stage liver disease in the pediatric population. For liver based metabolic disorders(LBMDs),the decision for LT is predicated on a different set of paradigms. With improved outcomes post-transplantation, LT is no longer merely life saving, but has the potential to also significantly improve quality of life. This review summarizes the clinical presentation, medical treatment and indications for LT for some of the common LBMDs. We also provide a practical update on the dilemmas and controversies surrounding the indications for transplantation, surgical considerations and prognosis and long terms outcomes for pediatric LT in LBMDs. Important progress has been made in understanding these diseases in recent years and with that we outline some of the new therapies that have emerged.     

De-novo hepatocellular carcinoma after pediatric living donor liver transplantation

De-novo malignancies carry an incidence ranging between 3%-26% after transplant and account for the second highest cause of post-transplant mortality behind cardiovascular disease. While the majority of de-novo malignancies after transplant usually consist of skin cancers, there has been an increasing rate of solid tumor cancers over the last 15 years. Although, recurrence of hepatocellular carcinoma(HCC) is well understood among patients transplanted for HCC, there are increasing reports of de-novo HCC in those transplanted for a non-HCC indication. The proposed pathophysiology for these cases has been mainly connected to the presence of advanced graft fibrosis or cirrhosis and always associated with the presence of hepatitis B or C virus. We report the first known case of de-novo HCC in a recipient, 14 years after a pediatric living related donor liver transplantation for end-stage liver disease due to biliary atresia without the presence of hepatitis B or C virus before and after transplant. We present this case report to increase the awareness of this phenomenon and address on the utility for screening and surveillance of hepatocellular carcinoma among these individuals. One recommendation is to use similar guidelines for screening, diagnosis, and treatment for HCC as those used for primary HCC in the pre-transplant patient, focusing on those recipients who have advanced fibrosis in the allograft, regardless of etiology.     

Pretransplantation fetal-maternal microchimerism in pediatric liver transplantation from mother

AIM To investigate the rates of pretransplantation fetalmaternal microchimerism(MC) and its effect on rejection in children receiving maternal liver grafts. METHODS DNA or blood samples before liver transplantation(LT) were available in 45 pediatric patients and their mothers. The presence of pretransplantation MC to non-inherited maternal antigens(NIMAs)(NIMA-MC) in the peripheral blood was tested using nested PCRsingle-strand conformation polymorphism analysis for the human leukocyte antigen(HLA)-DRB1 alleles. NIMA-MC was successfully evaluated in 26 of the 45 children. Among these 45 pediatric LT recipients,23 children(51.1%) received transplants from maternal donors and the other 22 from non-maternal donors.RESULTS Among these 26 children,pretransplantation NIMAMC was detected in 23.1%(n = 6),6.1(range,0.8-14) years after birth. Among the children with a maternal donor,the rate of biopsy-proven cellular rejection(BPCR) was 0% in patients with NIMA-MC positivity(0/3) and those with HLA-DR identity with the mother(0/4),but it was 50% in those with NIMA-MC negativity(5/10). Patients with NIMA-MC positivity or HLA-DR identity with the mother showed significantly lower BPCR rate compared with NIMA-MC-negative patients(0% vs 50%,P = 0.04). NIMA-MC-positive patients tended to show lower BPCR rate compared with NIMAMC-negative patients(P = 0.23). CONCLUSION The presence of pretransplantation NIMA-MC or HLADR identity with the mother could be associated with BPCR-free survival in pediatric recipients of LT from maternal donors.     

Surgical complications and long-term outcome in pediatric liver transplantation

BACKGROUND/AIMS: Liver transplantation has been widely accepted for the treatment of children with end-stage liver disease over the last 10 years particularly with the advent of reduced-size liver transplant technique. This study reviewed the perioperative and long-term results in the pediatric program of the Queensland Liver Transplant Service, Brisbane, Australia. METHODOLOGY: Retrospective analysis was performed in 153 children who received 176 liver grafts between 1985 and 1995, including 109 (62%) reduced-size and 67 (38%) whole liver grafts. Median follow-up period was 5.3 years. RESULTS: One-, 5-, and 10-year patient and graft survival rates were 82% and 74%, 75% and 63%, and 70% and 60%, respectively. Normal physical and intellectual development was observed in 98% of survivors. There were no significant differences in patient or graft survival rates between transplants using reduced-size and whole liver grafts. Portal vein thrombosis was the most common vascular complication, occurring in 8%. Hepatic artery thrombosis occurred in 7%, including 11% of children less than 1 year old and 8% of those under 10 kg. Biliary complication was found in 16% and posttransplant gastrointestinal perforation in 19%. CONCLUSIONS: Liver transplantation has the potential to cure and allow development in children with end-stage liver disease.     

Living donor liver transplantation for pediatric and adult recipients

Living donor liver transplantation (LDLT) was initially developed to provide suitable liver grafts for pediatric patients with end-stage liver disease. This innovation was remarkable for the prospective nature of its development and the public discussions that resolved the ethical dilemma of removing a portion of a liver from a healthy donor for the benefit of another person. Since its inception, this procedure has been uniformly adopted by most pediatric transplant centers, with excellent results. Unfortunately, liver grafts obtained from this procedure did not provide sufficient hepatocyte mass for use in adult recipients. An adult donor procedure was, therefore, developed to provide larger liver grafts, which were derived from the right lobe of the liver. Much of the driving force for adult-to-adult LDLT has been in countries that lack the health-care infrastructure for obtaining deceased donors or have cultural objections to deceased donor transplantation. In developed countries, the initial growth of adult-to-adult LDLT has been tempered by notable donor complications, including death, but it continues to have an important role in providing life-saving liver grafts for recipients who are unable to compete for deceased donor grafts in the current organ-allocation system.     

Beyond five years: Long-term follow-up in pediatric liver transplantation

Pediatric liver transplant patients are now routinely surviving 10 years or more. Beyond the first year after transplant, surgical biliary or vascular complications are rare, and the incidence of acute rejection episodes falls precipitously. Attention is turning to minimizing the toxicity of immunosuppressive regimens and their potential negative impact on growth, bone health, cognitive development, renal function, and quality of life. Innovative combinations of immunosuppressive medications are being used as initial management after transplantation to minimize acute rejection and allow rapid weaning of corticosteroids and reduction in maintenance levels of calcineurin inhibitors. The substitution of potentially less toxic immunosuppressive agents, such as mycophenolate mofetil and rapamycin, is being studied in patients who develop renal dysfunction. A major current emphasis is on defining the natural history of long-term graft injury and elucidating histopathologic changes that mimic autoimmune chronic active hepatitis but are likely a form of chronic rejection due to production by the recipient of antibodies to foreign graft antigens. As patients survive longer, we are seeing various forms of immune dysregulation engendered by the presence of the graft and chronic immunosuppression of the host. By defining the resulting patterns of graft injury and understanding their immunopathogenesis, we can devise rational adjustments in immunosuppression that will preserve graft function and maximize graft life.