Pediatric liver transplantation

It takes a village: primary care of the pediatric liver transplant recipient

PURPOSE OF REVIEW

Long-term survival is now the rule rather than the exception for infants and children who undergo liver transplantation for end-stage liver disease, metabolic liver conditions and a variety of other indications. Pediatricians and primary care providers play vital roles in the care and management of this patient population. The purpose of this review is to highlight key aspects important to the care of the pediatric liver transplant recipient.

RECENT FINDINGS

Significant advances in immunosuppressive therapies and surgical techniques have contributed to improved graft and patient survival rates, shifting the focus beyond immediate survival to strategies to minimize comorbidities related to long-term immunosuppression during growing years, attend to patient and parent-reported outcomes and enhance quality of life. A multidisciplinary approach allows for monitoring and surveillance of both routine (growth, nutritional rehabilitation, cognitive development, mental and psychosocial health, contraception and daily activities) and transplant-related (adverse effects of immunosuppression, susceptible infections, extra-hepatic systems, transition from childhood to adolescence to adulthood) themes.

SUMMARY

Effective communication between the primary care physician and the transplant team is imperative for optimizing best outcomes. The primary care provider should be aware of the multifacet nature of posttransplant management, which includes medication regimens, common complications and infections.

Oral health of pediatric liver transplant recipients

To evaluate oral health conditions in pediatric liver transplant recipients, with special focus on caries, green staining of the teeth, gingival bleeding, and gingival overgrowth. 40 patients (mean age 11.6 years) were examined at a routine follow-up visit, 6 months to 16 years after liver transplantation at the Swiss Center for Liver Disease in Children. After the medical examination, participants were further examined for the presence of dental caries, periodontal disease, GE, and GTC. The mean decay, missing, and filled teeth (dmft/DMFT) score was 3.8. 45% of the participants presented at least one carious lesion. Two-third of the participants had more than 20% of sites with the presence of plaque and gingival inflammation. Signs of GE were found in 18% and GTC in 30% of the participants. A positive correlation was identified between GTC and peak serum bilirubin (P<.001) and primary diagnosis of cholestatic disease (P=.04). Gingival inflammation was associated with plaque (P<.001), use of immunosuppressive medication (P=.04), and was more pronounced in children with cholestatic disease (P=.007). Children and young adults with liver transplants presented a rather poor oral health status. Liver transplant physicians should counsel patients for regular dental follow-up in order to avoid serious dental infections.

Population pharmacokinetic and pharmacogenetic analysis of tacrolimus in paediatric liver transplant patients

AIMS

To build a population pharmacokinetic model that describes the apparent clearance of tacrolimus and the potential demographic, clinical and genetically controlled factors that could lead to inter-patient pharmacokinetic variability within children following liver transplantation.

METHODS

The present study retrospectively examined tacrolimus whole blood pre-dose concentrations (n = 628) of 43 children during their first year post-liver transplantation. Population pharmacokinetic analysis was performed using the non-linear mixed effects modelling program (nonmem) to determine the population mean parameter estimate of clearance and influential covariates.

RESULTS

The final model identified time post-transplantation and CYP3A5*1 allele as influential covariates on tacrolimus apparent clearance according to the following equation: TVCL = 12.9 x (Weight/13.2)(0.75) x EXP(-0.00158 x TPT) x EXP(0.428 x CYP3A5) where TVCL is the typical value for apparent clearance, TPT is time post-transplantation in days and the CYP3A5 is 1 where *1 allele is present and 0 otherwise. The population estimate and inter-individual variability (%CV) of tacrolimus apparent clearance were found to be 0.977 l  h(-1)  kg(-1) (95% CI 0.958, 0.996) and 40.0%, respectively, while the residual variability between the observed and predicted concentrations was 35.4%.

CONCLUSION

Tacrolimus apparent clearance was influenced by time post-transplantation and CYP3A5 genotypes. The results of this study, once confirmed by a large scale prospective study, can be used in conjunction with therapeutic drug monitoring to recommend tacrolimus dose adjustments that take into account not only body weight but also genetic and time-related changes in tacrolimus clearance.

Choledochoduodenostomy in pediatric liver transplantation

Reconstruction of the bile ducts during pediatric liver transplantation is generally performed by a Roux-en-Y CDJ because direct duct-to-duct anastomosis CC is often not possible. Anastomosis of the donor liver bile duct to the duodenum CDD provides another option. We provide preliminary evidence that CDD is an alternative technique for biliary reconstruction when CC is not possible in pediatric liver transplant recipients that have a hostile abdomen or to preserve bowel length.

METHODS

From 2007 to 2008, a total of 19 pediatric cadaveric liver transplants were performed at our center. Four of the 19 had a bile duct reconstruction by CDD.

RESULTS

CDD reconstruction was used in patients who received a liver transplant for a diagnosis of PSC, congenital hepatic fibrosis, biliary atresia, and Alagille syndrome. The ages of the patients were 17 and 10 yr and 10 and 17 months. Three grafts were whole cadaveric livers, and one was a reduced left lobe. CDD was used to revise a prior anastomosis in one patient who had a previous Roux-en-Y that was unusable during the retransplant, and another to repair a stricture in a second patient with a CC. We also performed a CDD in a patient with a hostile abdomen from previous surgery, and another patient to avoid short gut syndrome that a Roux-en-Y may have created. All patients are alive with functioning grafts with a follow-up of at least one yr. None of the patients developed clinically significant biliary complications (leak, stricture, cholangitis).

CONCLUSION

Our preliminary experience suggests that CDD is an option for biliary reconstruction in pediatric transplant patients with hostile abdomens or to preserve bowel length.

Randomized trial of basiliximab induction versus steroid therapy in pediatric liver allograft recipients under tacrolimus immunosuppression

Avoidance of corticosteroids could be beneficial after pediatric liver transplantation (LTx). To test this hypothesis, we performed a randomized prospective study to compare immunosuppression with tacrolimus (TAC) and steroids versus TAC and basiliximab (BAS) after pediatric LTx. Seventy-two patients were recruited, 36 receiving TAC and steroids and 36 TAC and BAS. The primary endpoint was the occurrence of the first rejection episode. Secondary endpoints were the cumulative incidence and severity of rejection, patient and graft survival, and incidence of adverse events. Overall 1-year patient and graft survival rates were 91.4% and 85.5% in the steroid group, and 88.6% and 80% in the BAS group (p = NS). Patients free from rejection were 87.7% in the BAS group and 67.7% in the steroid group (p = 0.036). The use of BAS was associated with a 63.6% reduction in incidence of acute rejection episodes. Overall incidence of infection was 72.3% in the steroid group and 50% in the BAS group (p = 0.035). We conclude that the combination of TAC with BAS is an alternative to TAC and steroid immunosuppression in pediatric LTx, which allows for a significant reduction in the incidence of acute rejection and infectious complications.

Mortality risk score in liver transplantation: changes over time in its predicting power

Since the onset of our liver transplantation program in 1992, 362 transplants were performed in 338 children. A risk score for predicting mortality was designed and implemented over time. The description of a method utilized to design the risk score, changes in mortality rate over 12 yr and the analysis of factors that might have influenced these changes are presented and discussed in this paper.

PATIENTS AND METHODS

Cox regression analysis was applied to a retrospective sample of 110 patients with liver cirrhosis, transplanted between 1992 and 2000. A risk score was prepared using beta coefficients of the two significant variables related to survival time: age (1.08, p=0.02) and bilirubin levels (0.93, p=0.03), and two groups were identified: low- and high-risk score. The score was applied in two consecutive samples: 2000-2002 and 2002-2004.

RESULTS

In the first sample (1992-2000), we found 69 and 41 as low- and high-risk patients, with a median survival time of 93.13 and 2.93 months (p=0.0001). In the 2000-2002 sample, a median survival time of 41.7 and 2.33 months (p=0.03) was found for low- and high-risk groups, respectively. In the third sample (2002-2004), there was a remarkable decrease in mortality in the high-risk group (n=29) and the score did not discriminate between high- and low-risk groups (p=0.35).

CONCLUSION

A scoring system to identify risk levels in liver transplantation patients is an operative and powerful tool during a given period of time but it has to be updated as risk factors will vary following the team's learning curve.

Left and right lobe split-liver transplantation for two paediatric recipients from a 9-year-old donor

Liver splitting increased the number of grafts for paediatric recipients. Usually the two left lateral segments are given to a child and the remaining liver to an adult recipient. Splitting into a right and a left lobe may allow a small adult to benefit from the left lobe while the right lobe goes to another adult recipient. Splitting of paediatric grafts, however, has rarely been performed. We here report on a case where the liver from a 9-year-old donor was ex situ split along the principal fissure creating a right and left lobe which provided grafts for two children aged 2 and 3 years. Immunosuppression consisted of Tacrolimus-based triple drug therapy. Recovery was completely uneventful in both children who are alive and well with normally functioning grafts 11 months following transplantation. These cases demonstrate the feasibility of splitting even paediatric grafts for two small children.