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Liver transplant

From Surgopaedia

Indications

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  • Acute or fulminant liver failure as per King's College criteria - see separate topic
  • Chronic liver disease with MELD score >=15 by any aetiology
  • MELD exception points:
    • HCC as per Milan criteria (see separate topic)
    • Hilar cholangiocarcinoma
    • Hepatopulmonary syndrome
    • Portopulmonary hypertension
    • Familial amyloid polyneuropathy
    • Primary hyperoxaliuria
    • Cystic fibrosis
    • Hepatic artery thrombosis
  • Liver disease with complicating medical conditions
    • Recurrent cholangitis with PSC
    • Refractory ascites
    • Refractory hepatic encephalopathy
    • Refractory variceal haemorrhage
    • Portal hypertensive gastropathy leading to chronic blood loss
    • Intractable pruritus in a patient with primary biliary cirrhosis
  • Other metabolic disorders
    • Alpha-1 antitrypsin deficiency
    • Some forms of glycogen storage disease
    • Tyrosinaemia
    • Haemochromatosis
    • Wilson disease
    • Acute intermittent porphyria

Contraindications

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  • Unable to tolerate GA due to cardiac or pulmonary disease
  • Active substance abuse
  • Active sepsis
  • Severe metabolic syndrome
  • Smoking
  • Inadequate or absent social support
  • Renal insufficiency is a relative contraindication

MELD - Model for End-stage Liver Disease - see main description under 'cirrhosis'

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  • Has been adopted as a measure of overall need for transplant and prioritisation
  • A MELD score of 15 potentially gives a survival advantage in liver transplant - below this the procedure is less likely to be justified
  • MELD scores <15 can still be an indication for transplant with PSC or HBV in particular
  • Predicts survival in patients with advanced liver disease

Terminology and approaches

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  • Types of transplant
    • Split liver transplantation
      • Either split right and left or left lateral (II-III)
      • Can be transplanted into two people, especially good for children
      • Must be very good quality liver (age <50, BMI, GGT <50, no steatosis)
    • Auxiliary transplant
      • Donor allograft placed heterotopically, leaving the native liver in place
      • Done when there is a chance of recovery
      • In that case, the immunosuppression would be stopped, and the transplant graft would atrophy
    • Orthotopic transplant
      • Main approach - native liver removed and transplant placed
      • Three phases of anaesthetic
        • Hepatectomy
        • Anhepatic - coagulopathy and acidosis
        • Post-implantation phase - ischaemia and reperfusion syndrome
  • Bicaval anastomosis
    • Native liver and retrohepatic IVC resected and replaced by donor liver including IVC
      • Retro-hepatic IVC removed along with the liver
  • Piggyback technique (most common technique in Austin nowadays)
    • Need to create a wide caval anastomosis to prevent venous stricturing, which will lead to Budd-Chiari
    • Caval-preserving techniques makes it easier to avoid venovenous bypass while the anastomosis is taking place, which is beneficial

Approach to an orthotopic piggyback liver transplant

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  • Mercedes Benz incision
  • Hepatectomy
    • Division ligamentous attachments, CBD, CHA, HV and PV
  • Implantation
  • IVC anastomosis
  • PV reconstruction
    • Usually performed end to end
    • Main thing is to avoid kinking/stenosis
    • Allow for a 'growth factor' when tying off the circumferential running suture - because it will expand slightly when flow is returned
    • Getting the length right is important - if too much donor length is used, kinking will occur
    • May need to do PV thrombectomy if PV thrombosis is present
  • Arterial reconstruction
    • Usually direct end to end anastomosis between donor and recipient HA
    • Carrel patch should be used to decrease hepatic artery thrombosis
    • Poor hepatic artery inflow will cause a problem - may need to dissect more proximal to it. Maybe use a donor iliac artery graft to do an accessory conduit direct form aorta.
  • Biliary anastomosis
    • Direct duct to duct vs Roux-en-Y hepaticojejunostomy/choledochojejunostomy
    • Duct to duct is preferable if recipient duct is normal - allows access via ERCP and preserves native anatomy
      • If there is a significant size discrepancy, side to side anastomosis can be used
    • Roux-en-Y is used for a retransplant or for PSC, although the latter is now controversial, and duct to duct anastomosis may still be appropriate
    • T-tubes should not be routinely used for biliary anastomosis

Complications

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  • Immediate
    • Bleeding - coagulopathy - 10% RTT rate
    • Primary non-function - 5% - doesn't regain consciousness, ALT >5000, INR >2.5. Re-list for transplant.
    • Hyper-acute rejection - very uncommon.
  • Early
    • General
    • Bile leak
      • Occurs in 20%
      • Most self-limited - as long as it's well-drained
      • Biliary peritonitis requires laparotomy and conversion to hep-jej
      • Suspect with fluid collection near porta hepatica
      • ERCP can diagnosis and treat
    • Bile duct stricture
      • Anastomotic
        • Early - often technical issues - small calibre ducts or diathermy burns
        • Later - ischaemia at the end of the donor duct leading to fibrotic healing
        • Balloon dilatation with stent, stent replacement every 3 months. Works very well.
      • Non-anastomotic
        • Ischaemia secondary to preservation injury/donation after cardiac death/prolonged vasopressors/rejection/hepatic artery insufficiency/recurrent disease
        • Difficult management - metallic stents may work - may need conversion to Roux-en-Y or re-transplantation
      • MRCP can diagnose, but ERCP better due to therapeutic options
    • Hepatic artery thrombosis
      • Sudden rise in transaminases, biliary problem or hepatic necrosis may be first sign of trouble
      • PV flow often gives enough oxygenation to keep allograft going, but biliary system is dependent on hepatic arterial supply
        • Hepatic artery flow <200ml/min is a/w sixfold increase in hepatic artery thrombosis
      • Duplex USS, MRA or CT can diagnose
      • Thrombectomy successful in 50%
      • Graft failure high probability otherwise
    • PV thrombosis
      • RFs
        • Technical - kinking due to excessive length
        • Preop PVT
        • Hypercoagulability
        • Small PV
        • Reconstruction with vein conduit
      • Seen clinically with ascites and portal hypertension
      • Early PVT can be devastating leading to graft failure -> attempt thrombectomy
    • IVC or HV thrombosis
    • Intra-abdominal sepsis
    • Impaired consciousness
      • Encephalopathy
      • Cerebral infarcts
      • Air embolus
    • Acute rejection
      • Doesn't influence long-term outcome if treated
      • Clinical - low-grade fever, eosinophilia, worsening LFTs
      • Diagnosed on biopsy
  • Late
    • Chronic rejection
      • Bile ducts are obliterated (vanishing bile duct syndrome)
      • Rising ALP and bilirubin
      • Obliteration of small and medium-sized arteries
    • Hepatic artery stenosis
      • 2-10%
      • Insidious - often asymptomatic, or just mild LFT elevation
      • Pick it up with routine screening USS
      • Surgical revision or endovascular interventions such as PTA - PTA now first-line though

Outcomes

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  • Five year survival in 2009 was 70%
  • Poor prognostic indicators:
    • Age > 65
    • HCV (likely that this effect will be reduced now that we can cure it)
    • Malignancy
    • Re-transplantation
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