Question 6

College answer

Not available.

Discussion

Mechanism of TIPS:

• Portal hypertension causes the majority of the morbidity from chronic liver disease
• This is due to raised portal pressure
• TIPS decompresses the portal circulation by allowing it to empty into the comparatively lower central venous circulation
• Ergo, TIPs should relieve the majority of the morbidity from chronic liver disease

Indications:

• Refractory ascites or hepatic hydrothorax
• Refractory rebleeding in variceal disease
• Hepatorenal syndrome
• Hepatopulmonary syndrome
• Bridge to liver transplant
• Hepatic vein thrombosis
• Hepatic veno-occlusive disease
• Portal vein thrombosis

Contraindications for portal venous shunt (Boyer and Haskal, 2009)

• Absolute contraindications:
  • Moderate to severe pulmonary hypertension
  • Congestive heart failure
  • Multiple hepatic cysts
  • Uncontrolled sepsis
  • Uncontrolled biliary obstruction
  • Total portal vein thrombosis (in the absence of any patent intrahepatic branches)
• Relative contraindications:
  • A MELD score above 18
  • Central hepatocellular carcinoma
  • Portal vein thrombosis (in the absence of an experienced operator)
  • Hepatic vein thrombosis
  • Severe coagulopathy or thrombocytopenia

• Technical complications:

  • Vascular access complications
  • Hepatic damage (through-and-through puncture): risk of intraperitoneal haemorrhage is 1-2%
  • Haemobilia (damage to the biliary tree)
  • Shunt stenosis or thrombosis (it happens in up to 70%)
  • Shunt migration
  • Hepatic vein stenosis (this can sabotage a future transplant)

• Complications from portal venous shunt:

  • Worsening hepatic encephalopathy
  • Shunt thrombosis or portal vein thrombosis (7-10%). If there is already a portal vein thrombosis, this risk appears to increase somewhat (Perarnau et al, 2010) - which probably reflects the overall prothrombotic diathesis.
  • Bilirubin rise: the diseased liver doesn't even get a chance to metabolise it
  • Ischaemic hepatitis: the liver gets much of its oxygen from the portal vein, and even in spite of the hepatic arterial buffer response there is a risk of ischaemic hepatitis.
  • Right heart failure (the venous return to the heart is increased. The RV may not be prepared for this)
  • Tricuspid endocarditis (organisms may now travel directly from the leaky gut into the systemic circulation)
  • Haemolysis (due to the direct shearing effect of being in contact with the shunt)
  • "Unmasked" cardiomyopathy: the TIPS returns splanchnic blood to the heart and acts as a volume challenge, and if there was pre-existing cardiomyopathy, it may be dramatically revealed in this manner.
  • Shunt infection may occur, where the shunt itself may become the source of infection.