martes, 3 de septiembre de 2019

TIPS Procedure Complications

Download PDF Copy

Although the transjugular intrahepatic portosystemic shunt (TIPS) procedure is performed in patients with severe liver disease, the complication rate is less than 5%. These must be identified and treated promptly to avoid danger to life.

Procedural complications

Vascular Access

The catheter through which the procedure is performed is introduced through a puncture in the vascular wall. This may cause carotid artery injury and right atrial perforation. Carotid arterial rupture may occur when the catheter is attempted to be passed through the internal jugular vein. Again, perforations or breaches of the right atrial wall may occur. These are due to migration of the long 10-F access sheath used in this procedure and which is left behind in some cases to facilitate the administration of intravenous fluids, treatments, or subsequent follow-up. It may cause lesions in the wall of the right atrium.

Difficulty Faced During Portal Vein Localization

An important step in the TIPS procedure is localizing the portal vein. If the accurate position of the portal vein is identified, then the radiologist can target the vein precisely. This avoids the need to make repeated punctures with the consequent risk of unwanted bleeding.

The portal vein is usually localized using a wedged hepatic venogram. A balloon-occlusion catheter or an angiographic catheter is placed in one of the hepatic veins and through this carbon dioxide (CO2) or iodine is injected to achieve the opacification of the portal vein. During this procedure, liver laceration may occur if the injection is given too forcefully.

Difficulties During Portal Vein Access

Gaining access to the portal vein is a very challenging step and various techniques have been proposed to ease this procedure. It is always preferable to avoid making repeated punctures so as to avoid vessel perforation and catastrophic bleeding. The hepatic veins are the first route of access but if they are not suitable, the inferior vena cava is tapped instead and the catheter is guided directly into the portal vein. This leads to increased risk of inferior vena cava laceration, however.

Damage to the hepatic artery is not uncommon during this procedure, but may be accompanied by severe bleeding and even death. Hepatic artery embolization is to be avoided during TIPS as it increases the risk of hepatic failure in the post-operative period. The weakened hepatic artery wall may also form a pseudoaneurysm or become the point of hepatic infarction.

Puncture and opacification of the biliary duct are quite common during the performance of TIPS. Injury of the bile duct is very rare. Infections, shunt stenosis, and fever are some of the symptoms that occur due to the formation of a fistula between the shunt tract and the biliary system.

Difficulties During Stent Placement

Difficult stent placement may lead to shunt failure as a result of technical problems.

The commonly used stent at present is the Wallstent, which can be repositioned and recaptured. But this type of stent tends to recoil at the end of the hepatic vein, making the stent length inadequate to sustain shunt longevity.

Stent migration is a serious condition and needs immediate clinical attention. When it moves forward, an additional stent is required to be placed in tandem to cover the whole tract with the stent. If the original stent moves into the right atrium centrally, it may result in cardiac chamber perforation or hemodynamic complications.

Stent migration from the right atrium can result in aortoatrial fistula development and atrial perforation. This subsequently leads to catastrophic outcomes. Shunt thrombosis may also result from stent migration.

Post-Procedural Complexities

TIPS diverts the blood flow through the portal vein with the help of the shunt, in order to reduce the portal system pressure. However, this increases the volume of circulating blood in patients with liver cirrhosis. After the successful implementation of TIPS, there are inevitable changes in pulmonary artery pressure, pulmonary vascular resistance, right atrial pressure, and cardiac indices. These changes may lead to severe decompensation in post-TIPS patients.

A functioning shunt leads to a change in the direction of portal flow which can lead to liver failure after TIPS. 25% of blood to the liver is supplied by the hepatic artery and the remaining blood flow is via the portal vein. The hepatic artery normally responds to a sudden reduction in portal artery flow and compensates for this drop. When this is absent, a rapid fall in hepatic blood flow can precipitate hepatic failure with a steep rise in the bilirubin level. This can culminate in rapidly progressing fulminant liver failure and death. The most common complication that develops after TIPS is hepatic encephalopathy, which is defined by confusion, irregular sleep patterns, and an overall change in the quality of life.

Occasionally, radiation injuries occur after a prolonged TIPS procedure. Many of these difficulties have been overcome by the development of new technology which makes it possible to do a total fluoroscopy within 20 to 30 min. Radiation injuries can be avoided by following the basic standards for decreasing radiation exposure.

Thus, the patient faces various potential complications during the TIPS procedure and the radiologist should be aware of their possibility and take steps to prevent them as far as possible.