Balloon-occluded retrograde transvenous obliteration (BRTO)

What is BRTO?

The liver is supplied by two blood vessels, the hepatic and portal vein arteries. In patients with cirrhosis due to changes in the liver, there is an increase in resistance within the liver which makes it difficult for the portal vein to empty into the liver. This causes what is commonly called portal hypertension, which refers increased high blood pressure in the portal veins. There might be non-cirrhotic causes of portal hypertension too.

Portal hypertension creates a situation like a traffic jam on the highway. The body tries to solve this by diverting the blood through other veins so that the flow continues (just like the police do when there is a problem on the highway). The veins which help empty the portal vein are smaller in size and are not used to the unusually high volume of blood coming through. With time, they adapt to accommodate this flow by increasing in size and becoming tortoise. When these veins dilate (enlarge) and become tortoise, they are called varices. They resemble the varicose veins that sometimes happen in legs, only in this case they are around the stomach or the esophagus. These veins are fragile and can burst or rupture, causing bleeding. One of the major possible complications of portal hypertension is gastric variceal bleeding. Gastric variceal bleeding is the bleeding that occurs when dilated vessels in the stomach rupture, and is associated with high morbidity (make you very sick) and mortality (may cause loss of life) rates.

BRTO is a minimally invasive technique that is used to treat gastric variceal bleeding. The procedure involves blocking the dilated vessels, reducing the risk of rupture. It can be used in addition to or as an alternative to TIPS, which used to be the primary treatment for gastric varices.

How does the procedure work?

The interventional radiologist will insert a balloon catheter (a thin, flexible tube with a tiny balloon at one end) through a vein in your thigh or neck and guide the catheter to the liver using fluoroscopy for guidance. The catheter is then directed to the gastrorenal or gastrocaval shunt and the balloon is expanded to block the shunt.

The interventional radiologist will then perform a venography, which is a type of imaging technique in which X-rays are used to see the vessels clearly. This will allow the interventional radiologist to confirm exactly which vessels need to be treated and if there are any other abnormal or dilated vessels which have not previously been identified. A medication will then be injected into the dilated vessels through the catheter, until they are completely filled. This medication will remain in the vessel for a short period of time, and will then be removed under fluoroscopy.

Another venography will then be performed, to confirm that the blood flow in the shunt has stopped. Finally, the balloon will be deflated and the interventional radiologist will withdraw the catheter.

Why perform it?

You may be advised to undergo this procedure if you are at risk of or already have gastric variceal bleeding with or without hepatic encephalopathy. Hepatic encephalopathy is a condition caused due poor liver function. You may experience it as black outs or memory difficulties. It may be temporary.

BRTO has tended to be used to prevent gastric variceal bleeding. It is also an effective therapy for sclerosis (closing) of similar shunts (dilated abnormal veins) in other regions of the body in patients with the additional complication of hepatic encephalopathy. One of the greatest advantages of BRTO is its preservation of liver function, there by reducing the risk of hepatic encephalopathy. Moreover, the increase of blood flow towards the liver after BRTO can also improve liver function in cases where the patient has cirrhosis (scarring of the liver).

What are the risks?

Procedure-related complications are minor and include bleeding and infection. In rare cases, the blockage of the blood to the gastric varices can further increase the pressure on the liver, causing damage to the liver.

The most serious complications of the procedure, however, are related to the medication used to block the vessels, which is called ethanolamine oleate. Inflow of a relatively large amount of ethanolamine oleate can lead to serious complications. These complications include pulmonary embolism (blockage in a lung’s main artery), fluid in or around the lungs, hypersensitivity, fever, problems with blood flow to the heart and the formation of small blood clots in vessels throughout the body. Ethanolamine oleate also causes haemolysis, which is the rupturing of red blood cells. Newer medications have reduced these risk. There are variations in the techniques with regards to materials used to block or close the veins. Your doctor will choose which one is right for you after considering other risk factors you may have.

Other risks include displacement of metallic products used. Your physician can explain to you the course of action that will be taken if that were to happen.

Bibliography

1. Kitamoto M, Imamura M, Kamada K, et al. Balloon-occluded retrograde transvenous obliteration of gastric fundal varices with hemorrhage. AJR Am J Roentgenol. 2002;178:1167–1174.
2. Wael E. A. Saad, M.D., F.S.I.R.1 and Saher S. Sabri, M.D Balloon-occluded Retrograde Transvenous Obliteration (BRTO): Technical Results and OutcomesSemin Intervent Radiol. Sep 2011; 28(3): 333–338.