Durable Clinical and Immunologic Advantage of Living Donor Liver Transplantation in Children

Antithrombin supplementation for prevention of vascular thrombosis after pediatric liver transplantation

AIMS

After liver transplantation (LT), synthesis of coagulation factors by the graft recovers faster for pro thrombotic than anti thrombotic factors, resulting in a potential pro thrombotic imbalance. We studied the thrombotic and hemorrhagic complications in our pediatric LT series, providing supplementation of fresh frozen plasma (FFP) and/or antithrombin (AT) in the prophylactic antithrombotic regimen.

METHODS

This was a retrospective observational single center study. All isolated pediatric LTs performed between 1/11/2009 and 31/12/2019 (n = 181) were included. Postoperatively, in addition to low molecular weight heparin, 22 patients (12%) received FFP (10 ml/kg twice daily for 10 days), 27 patients (15%) were given FFP (reduced duration) and AT (50-100 IU/kg/day if AT activity remained <70%), and 132 (73%) received AT only. Complications, outcome, and coagulation profiles in postoperative days 0-10 were analyzed.

RESULTS

In all three treatment groups, AT activity normalized by day 4 while prothrombin remained <70% of normal until day 9. Hepatic artery thrombosis (HAT), portal vein thrombosis (PVT), and hemorrhagic complications occurred in 2.8%, 3.3%, and 3.9% of LTs. One- and 5-year patient and graft survival were 88% (±2.4% Standard Error) and 84% (±2.5%), and 86% (±2.6%) and 84% (±2.7%), respectively, without difference between groups. HAT were associated with low AT on days 0 and 1, and PVT with low AT on day 0.

CONCLUSIONS

Low antithrombin activity after LT was associated with postoperative thromboses. FFP and/or AT supplementation allowed early normalization of AT activity, while thrombotic or hemorrhagic complications were rare, suggesting efficient and safe management of post-LT coagulopathy.

Impact of allograft types on outcomes after pediatric liver transplantation due to biliary atresia

BACKGROUND

Several surgical strategies, including split donor transplantation and living donor transplantation, have been used to increase the donor liver pool. This report focuses on the effects of whole, split, and LDLT on recipient outcomes.

METHODS

We retrospectively analyzed the records of all patients with biliary atresia at Tianjin First Central Hospital between April 2013 and December 2019.

RESULTS

A total of 882 patients were included and divided into three groups by graft type, with 198 in the whole-liver-transplantation group, 78 in the split liver transplantation group, and 606 in the LDLT group. The median follow-up time was 39 months, patient survival rates of three groups were 94.4%, 88.5%, and 95.0%, respectively, and graft survival rates were 90.2%, 83.3%, and 94.7%, respectively. We divided the split liver transplantation group into two subgroups according to the donor's age, and patient survival rates exhibited a significant difference only in the group whose donor age was over 45 years. The postoperative complication rates were significantly higher with respect to hepatic artery thrombosis, portal stenosis, and AR; and lower in hepatic venous stenosis, PTLDs, CMV virus, and EBV infection in the WLT group. Our multivariate model showed that donor age ≥45 years, RBC transfusion, pneumonia, and HAT were the independent predictors of allograft loss.

CONCLUSIONS

The survival of split liver transplantation group was slightly lower. The types of complications are different from different graft types. Therefore, postoperative monitoring and treatment need to be adjusted according to the different graft types used.

Immunologic benefits of maternal living donor allografts in pediatric liver transplantation: fewer rejection episodes and no evidence of de novo allosensitization

BACKGROUND

Pediatric liver transplant (LT) recipients of maternal living liver donor (LLD) grafts have been reported to experience fewer rejection episodes. However, it is unclear whether this benefit translates to reduction in developing donor-specific antibody (DSA) among maternal-LLD recipients. The aim of this study was to compare immunologic outcomes among maternal-LLD, non-maternal-LLD, and deceased donor liver transplant (DDLT) recipients.

METHODS

Children (≤18 years) who underwent LT between 1/1998 and 12/2019 at two high-volume LT centers in North America were evaluated. Patients were divided into three groups by type of graft received (maternal-LLD, non-maternal LLD, and DDLT). Clinical variables and outcomes were compared according to each graft type.

RESULTS

A total of 450 pediatric primary LT were analyzed: 275 (61.1%) DDLT, 73 (16.2%) maternal-LLD, and 102 (22.6%) non-maternal-LLD. Children receiving LLD grafts were less likely to develop rejection when compared to the DDLT group (DDLT 46.9% vs. maternal-LLD 31.5% vs. non-maternal-LLD 28.4%, p = 0.001). There was no difference in rejection rates between maternal and non-maternal-LLD recipients. A higher percentage of maternal-LLD recipients were on immunosuppression monotherapy compared to non-maternal-LLD and DDLT recipients (6.7% vs. 1.2 vs. 2.4%, respectively). A subgroup of 68 patients were tested for DSA post-LT. Maternal-LLD recipients were less likely to develop de novo DSA (maternal-LLD 11.8% vs. non-maternal-LLD 19.3% vs. DDLT 43%, p = 0.018). None of the maternal-LLD recipients developed antibody-mediated rejection.

CONCLUSIONS

These data support the concept of immunologic benefit of maternal-LLD in pediatric LT, with lower rates of rejection and allosensitization post-LT when compared to DDLT recipients.

Clinical characteristics of immune tolerance after pediatric liver transplantation

Background

Clinical operational tolerance is the ultimate goal for liver transplantation. This study aimed to investigate the clinical characteristics of immune tolerance after pediatric liver transplantation and to identify the possible predictors.

Methods

The clinical data from 37 cases of pediatric patients 2 year later after liver transplantation surgery in the Children’s Hospital of Chongqing Medical University, China, were retrospectively analyzed. According to the status of the current immunosuppressant medications of the patients, they were divided into tolerance (n = 15) and Control (n = 22) groups. The current status regarding prope/operational tolerance was reviewed and screened based on the immunosuppressant medications.

Results

The patients in the tolerance group were younger than that of Controls (p < 0.001). The children in the tolerance group experienced no acute rejection episode and exhibited no obvious abnormalities in the liver function during the continuous follow-up period. The primary disease of the tolerance group were more often diagnosed with biliary atresia (p = 0.011), and received with a living donor liver graft (p = 0.005). There were less glomerular function, diabetes mellitus, arterial hypertension events presented in the tolerance group compared with the control group, indicating low toxicity profile.

Conclusion

In the current study, there were really certain quantity of recipients following liver transplantation attained long term immune tolerance, with low toxicity and satisfied liver graft function. The younger age of the recipient and maternal donor seems to promote long-term clinical immune tolerance. Further work in larger series should be required to describe the overall perspective of tolerance.

Long-term Outcomes of Pediatric Living Versus Deceased Donor Liver Transplantation Recipients: A Systematic Review and Meta-analysis

Living donor liver transplantation (LDLT) emerged in the 1980s as a viable alternative to scarce cadaveric organs for pediatric patients. However, pediatric waitlist mortality remains high. Long-term outcomes of living and deceased donor liver transplantation (DDLT) are inconsistently described in the literature. Our aim was to systematically review the safety and efficacy of LDLT after 1 year of transplantation among pediatric patients with all causes of liver failure. We searched the MEDLINE, Medline-in-Process, MEDLINE Epub Ahead of Print, Embase + Embase Classic (OvidSP), and Cochrane (Wiley) from February 1, 1947 to February 26, 2020, without language restrictions. The primary outcomes were patient and graft survival beyond 1 year following transplantation. A meta-analysis of unadjusted and adjusted odds and hazard ratios was performed using a random-effects model. A total of 24 studies with 3677 patients who underwent LDLT and 9098 patients who underwent DDLT were included for analysis. In patients with chronic or combined chronic liver failure and acute liver failure (ALF), 1-year (odds ratio [OR], 0.68; 95% confidence interval [CI], 0.53-0.88), 3-year (OR, 0.73; 95% CI, 0.61-0.89), 5-year (OR, 0.71; 95% CI, 0.57-0.89), and 10-year (OR, 0.42; 95% CI, 0.18-1.00) patient and 1-year (OR, 0.50; 95% CI, 0.35-0.70), 3-year (OR, 0.55; 95% CI, 0.37-0.83), 5-year (OR, 0.5; 95% CI, 0.32-0.76), and 10-year (OR, 0.26; 95% CI, 0.14-0.49) graft survival were consistently better in LDLT recipients compared with those in DDLT recipients. In patients with ALF, no difference was seen between the 2 groups except for 5-year patient survival (OR, 0.60; 95% CI, 0.38-0.95), which favored LDLT. Sensitivity analysis by era showed improved survival in the most recent cohort of patients, consistent with the well-described learning curve for the LDLT technique. LDLT provides superior patient and graft survival outcomes relative to DDLT in pediatric patients with chronic liver failure and ALF. More resources may be needed to develop infrastructures and health care systems to support living liver donation.

Maternal versus paternal living kidney transplant donation is associated with lower rejection in young pediatric recipients: A Collaborative Transplant Study report

BACKGROUND

Approximately 1700 children per year with end-stage kidney disease undergo kidney transplantation in Europe and the United States of America; 30%-50% are living donor kidney transplantations. There may be immunological differences between paternal and maternal donors due to transplacental exchange of cells between the mother and fetus during pregnancy leading to microchimerism. We investigated whether the outcome of living-related kidney transplantation in young children is different after maternal compared with paternal organ donation.

METHODS

Using the international Collaborative Transplant Study (CTS) database, we analyzed epidemiological data of 7247 children and adolescents aged <18 years who had received a kidney transplant from either mother or father. Risk of treated rejection episodes and death-censored graft failure were computed using the Kaplan-Meier method and multivariable Cox regression.

RESULTS

In the recipient age group 1-4 years, the rate of treated rejection episodes in recipients of kidneys from maternal donors (N = 195) during the first 2 years post-transplant was significantly lower (hazard ratio HR = 0.47, p = .004) than in patients receiving kidneys from paternal donors (N = 179). This association between donor sex and risk of treated rejections was not observed in children aged 5-9 years. The 5-year death-censored graft survival in children aged 1-4 years with a maternal or paternal donor was comparable.

CONCLUSIONS

Maternal kidney donation in young pediatric renal transplant recipients is associated with an approximately 50% lower rate of treated rejection than paternal kidney donation. Whether this phenomenon is due to maternal microchimerism-induced donor-specific hyporesponsiveness must be evaluated in prospective mechanistic studies.

Living Donor Versus Deceased Donor Pediatric Liver Transplantation: A Systematic Review and Meta-analysis

Reduced-size deceased donors and living donor liver transplantation (LDLT) can address the organ shortage for pediatric liver transplant candidates, but concerns regarding technical challenges and the risk of complications using these grafts have been raised. The aim of this study was to compare outcomes for pediatric LDLT and deceased donor liver transplantation (DDLT) via systematic review.

METHODS

A systematic literature search was performed to identify studies reporting outcomes of pediatric (<18 y) LDLT and DDLT published between 2005 and 2019. A meta-analysis was conducted to examine peri- and postoperative outcomes using fixed- and random-effects models.

RESULTS

Overall, 2518 abstracts were screened, and 10 studies met criteria for inclusion. In total, 1622 LDLT and 6326 DDLT pediatric patients from 4 continents were examined. LDLT resulted in superior patient survival when compared with DDLT at 1, 3, and 5 y post-LT (1-y hazard ratio: 0.58, 95% confidence interval [CI] 0.47-0.73, P < 0.0001). Similarly, LDLT resulted in superior graft survival at all time points post-LT when compared with DDLT (1-y hazard ratio: 0.56 [95% CI 0.46-0.68], P < 0.0001]. The OR for vascular complications was 0.73 (95% CI 0.39-1.39) and 1.31 (95% CI 0.92-1.86) for biliary complications in LDLT compared with DDLT, whereas LDLT was associated with lower rates of rejection (OR: 0.66 [95% CI 0.45-0.96], P = 0.03).

CONCLUSIONS

This meta-analysis demonstrates that LDLT may offer many advantages when compared with DDLT in children and suggests that LDLT should continue to be expanded to optimize outcomes for pediatric LT candidates.

Neurological complications after living-donor liver transplantation in children

AIM

Liver transplantation (LT) has been used as a definitive management for children with end-stage liver disease or acute liver failure. Living-donor LT (LDLT) has been a common type of LT performed in Asian countries, including Japan, where deceased donors are rarely available. However, the neurological complications (NCs) associated with LDLT remain unknown. The purpose of this study was to clarify the characteristics of NCs in children after LDLT.

METHODS

This study is a retrospective observational study carried out at a tertiary children's hospital in Japan. We studied children who had undergone LDLT between January 2001 and January 2020.

RESULTS

We examined 602 cases of LT, of which 559 were LDLT cases (92.9%). NCs after LT were present in 21 cases (3.8%). The most common neurological symptoms were seizure (n = 17), whereas disturbance of consciousness without seizure was observed in four cases. The frequency of NCs for each of the indications was 12.2% for fulminant hepatic failure, 6.5% for metabolic liver disease, and 0.7% for cholestatic liver disease.

INTERPRETATION

We report the characteristics of NCs after LDLT in children. The frequency of NCs after LT was high in cases of fulminant hepatic failure and metabolic diseases, who might have had neurological symptoms or impaired consciousness before LT.

Understanding the Long-Term Impact of Living-Related Liver Transplantation on Youth and Young Adults and their Family

PURPOSE

The purpose of this mixed methods study was to better understand the long term impact of living-related liver donation (LRLD) on youth and young adult (YYA) recipients and their family.

DESIGN AND METHODS

Semistructured interviews were conducted with YYA, aged 11-18 years, who received a living donation from a parent. Interviews were audiotaped, transcribed, and analyzed to aggregate themes that represented the participants' views as live-liver recipients. An ethnographic process was conducted to understand the participants' social behavior. At interview, participants completed a demographics questionnaire and the Youth Quality of Life Instrument-Research Version (YQOL-R).

RESULTS

Thirteen adolescents were interviewed; six were re-interviewed as key informants. Three major categories were created from the data: Developing Identity, Redefining Family Relationships, Feeling Gratitude to Donors. The overarching theme was Resiliency. Findings from the YQOL-R showed no difference in overall scores or separate domains when compared with a reference population with no chronic illness.

CONCLUSION

Qualitative and quantitative data highlight the positive effect that LRLD can have on pediatric patients as they transition from childhood to adolescence to young adulthood.

PRACTICE IMPLICATIONS

As pediatric transplant centers in the United States soon mark 30 years of performing live-liver donation, recipients are becoming adults and understanding more clearly that the long-term effects of such donations will lead to improvements in future care.

Immunologic benefit of maternal donors in pediatric living donor liver transplantation

PURPOSE OF REVIEW

Long-term follow-up has suggested that pediatric LDLT may have superior outcomes compared to deceased donor recipients. In this review, we describe the subset of LDLT recipients with maternal donors that have lower reported rates of rejection and improved allograft survival.

RECENT FINDINGS

Pediatric LDLT recipients, particularly those with a primary diagnosis of biliary atresia who receive grafts from their mothers, have been reported to have lower rates of acute cellular rejection post-transplant and graft failure. Maternal-fetal microchimerism and the persistence of regulatory T cells may be related to improved outcomes observed in recipients with maternal donors. Further, recent studies have shown that up to 60% of pediatric LDLT recipients can undergo intentional withdrawal of immunosuppression and achieve long-term operational tolerance. The impact of graft type on operational tolerance has not been thoroughly investigated; however, investigation of tolerant pediatric LDLT patients with maternal donors may provide key insights into the mechanisms of immune tolerance.

SUMMARY

While excellent outcomes can be achieved in pediatric LDLT, there is still a measurable decrease in graft and patient survival over time post-transplant. Recipients of maternal donor liver transplants are a subset of patients who may be advantaged toward improved outcomes by means of immune tolerance.