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Intrahepatic Shunts

Intrahepatic Shunts

Direct Shunt embolisation - a novel technique for intrahepatic shunt closure

  • Superior way of intrahepatic shunt closure 
  • Superior long term outcome compared to other techniques
  • SCVS is the only referral centre in the UK offering this novel method
  • Patients can be booked directly for the intervention if adequate diagnostics (Angio-CT and blood tests) have been performed elsewhere
  • Please contact SCVS on 01425 485 615 and ask for Darren Kelly or Tobias Wagner if you have a patient which might be suitable

General information about intrahepatic shunt closure

What are the options for closing intrahepatic shunts?

There are three different techniques available

  • Surgical ligation
  • Stent&Coil technique
  • Direct Shunt embolisation (Novel technique used at SCVS)

Does closure of intrahepatic shunts always work?

The two main potential complications following closure of intrahepatic shunts are:

  • Development of portal hypertension
  • Formation of collateral secondary shunt vessels

Portal hypertension

Portal hypertension commonly develops following shunt closure as a consequence of poorly developed vasculature in the liver. Following shunt closure, the large blood volume normally draining from the gastrointestinal tract into the 
systemic circulation is partially occluded. In order for shunt closure to be successful gradual closure of the shunt, which 
allows hepatic vessels to re-develop, is key. Gradual closure using surgical ligation or stent & coil techniques can only achieved with repeated procedures. The novel Direct Shunt embolisation achieves gradual shunt closure after only one intervention in most patients, using a unique and complex heparinisation protocol.

Formation of collateral secondary shunt vessels

Hepatic veins have pre-connections between each other. These connections are usually non-patent and don't carry any blood flow in normal circumstances. However, with increased hepatic venous pressure these connections become patent, resulting in the formation of secondary 
collateral shunts 
Hepatic vein pressure increases if the hepatic vein instead of the shunt vessel itself is closed as this is often the case with surgical shunt ligation and the stent&coil technique. Direct Shunt embolisation does not carry this risk.

Formation of collateral shunt vessels

 

The intrahepatic shunt (black part of the vessel) connects the portal vein (purple vessel) with the hepatic vein (blue) and caudal vena cava. 'Toxic' blood reaches the systemic circulation via the shunt vessel.
The portal vein branches into the liver, but these branch vessesls are usually underdeveloped and only very few are present.
Several hepatic veins (small blue vessels) exist and drain the liver pranchyma.

 

 

There are preformed connections between all the hepatic veins (dotted lines). These remain closed and do not carry any blood flow as long as the pressure within the liver veins remains low

 

 

 

 

Ligation of the hepatic vein will dramatically increase the pressure within the hepatic veins

 

 

Pre-formed connections between the hepatic veins open and a new shunt vessel develops

 

 

Shunt closure techniques compared

Surgical Ligation

Depending on the type and location of the intrahepatic shunt, surgical ligation is usually performed at the level of the hepatic vein or at the level of the portal vein. If ligated at the level of the hepatic vein, then very likely secondary shunt vessels will often develop over time, resulting in a poor long term outcome. Ligation at the level of the portal vein impairs portal blood flow, resulting in severe portal hypertension. Often complete shunt closure cannot be achieved.

Stent & Coil Technique

A stent is placed in the caudal vena cava. Thereafter the hepatic vein is embolised with multiple small coils. This again represents a technique which closes the hepatic vein and not the shunt vessel itself. It is therefore prone to formation of secondary shunts.

 

 

Stent positioned in the vena cava. Coils embolise the hepatic vein

 

 

A collateral shunt vessel forms secondary to increased pressure in the hepatic vein following coil embolisation.

 

 

 

Direct Coil Embolisation (novel technique used at SCVS)

Direct Coil embolisation of the shunt positions a single large coil directly at the level of the shunt vessel. This avoids the risk of formation of secondary colateral shunts and results in a very good long term outcome for the patient.

 

Positioning of a single large coil at the level of the shunt preventing development of collateral shunts.

 

 

 

 

Complex heparinisation protocol guarantees gradual shunt closure and avoids severe portal hypertension.

 

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