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Liver Transplant

Indications



  • Primary liver diseases: Biliary Atresia comprises ~50% of all pediatric liver transplants, Alagille's syndrome, primary sclerosing cholangitis, Progressive Familiar Intrahepatic Cholestasis (PFIC)
  • Metabolic disease: Urea cycle defects, alpha-1 antitrypsin deficiency, glycogen storage disease, tyrosinemia
  • Fulminant Hepatic Failure: Viral hepatitis, autoimmune
  • Tumor: Hepatoblastoma, HCC


Organ Allocation

  • PELD (Pediatric End-stage Liver Disease) score, similar to adult MELD score used to determine priority
  • PELD consists of bilirubin, INR, serum albumin, age <1 yr, and growth failure. Additional PELD points for hepatopulmonary syndrome, urea cycle defects, and neoplasms
  • PELD not a predictor of 30 day or long-term outcome following transplantation

Graft Options

  • Whole organ transplantation is ideal
  • Split liver transplantation where single liver can be used with two recipients
  • Living donor transplantation
  • Graft to recipient body weight ratio (GRWR) used to determine optimal graft volume with a GRWR of 1-3%
  • Grafts from pediatric donors have improved outcomes in the pediatric population than grafts from adult donors (81 vs 63% 3 year graft survival in one study)

From: Boston Children's Hospital


Postoperative Care

  • Major general principles are:
    • Maintain patency of the graft vascular anastamoses (particularly the hepatic artery but also the portal and hepatic veins)
    • Provide normal to slightly supraphysiologic blood pressure to ensure adequate perfusion of the graft while avoiding significant hypertension that may predispose to bleeding
    • Communication with the transplant team is key
  • In general, we keep postoperative livers on the "wet" side and diuretics should be used judiciously, with the concern for volume depletion and vascular thrombosis
  • Similarly, vasoconstrictive agents should be used judiciously and only after discussion with the transplant team
  • Monitoring vascular patency is typically done with doppler ultrasound
  • Hepatic artery thrombosis has an estimated incidence of 1.7-10% overall
  • Understand that organ perfusion pressure is determined by the driving pressure (MAP) and the back pressure (typically Right Atrial Pressure as estimated by CVP but can also be abdominal compartment pressure if there is significantly elevated abdominal pressures or intracranial pressure in the case of cerebral edema). Thus, in most circumstances: Organ perfusion pressure = MAP- RAP (estimated by CVP)
  • Avoid hemoconcentration as this may predispose to increased viscosity and vascular thrombosis (our center typically aims for a hematocrit ~25%)
  • Immune supression (managed by the transplant service) typically consists of the calcineurin inhibitor tacrolimus as well as cyclosporine (mycophenolate mofetil) and steroids
  • Primary nonfunction (accounts for ~ 25% of all graft failure within 30 days) leads essentially to fulminant liver failure and requires retransplantation
  • Bleeding can be monitored both by the hematocrit as well as careful attention to surgical drainage devices' quality and quantity of drainage
  • Judicious treatment of coaguloapthy and thrombocytopenia with fresh frozen plasma and platelets should be emphasized, again balancing the risk of bleeding with that of vascular thrombosis
  • Reactive right sided pleural effusions are commonly seen
  • Sepsis can occur in the postoperative period as patients are immunocompromised 
  • Must consider EBV, CMV as these are the most common viral infections postoperatively (also check donor status)
  • Bile leaks can also occur (can occur secondary to bile duct ischemia from hepatic artery thrombosis or due to dehiscence of the anatastamosis)
  • Rejection, when it does occur, generally occurs about 7-16 days posttransplant
  • Hypertension common due to steroids, tacrolimus, and cyclosporine



References

1) S. McDiarmid: Current status of liver transplantation in children.Pediatr Clin North Am. 50:1335-1374 2003 14710783

2) J.C. Emond, et al.: Liver transplantation in the management of fulminant hepatic failure.Gastroenterology. 96:1583-1588 1989 2653944

3) E. Rand, K. Olthoff: Overview of pediatric liver transplantation. Gastroenterol Clin. 32:913-929 2003

4) Miloh T. Medical management of children after liver transplantation. Curr OpinOrgan Transplant. 2014 Aug 27. [Epub ahead of print] PubMed PMID: 25162538.

5) McDiarmid SV. Liver transplantation. The pediatric challenge. Clin Liver Dis. 2000 Nov;4(4):879-927. Review. PubMed PMID: 11232362.