Last updated: 02/17/2009

The portal vein carries blood from the stomach and abdominal organs to the liver. It is a major vein that splits into many branches. In people with liver failure and cirrhosis, a chronic degenerative liver disease causing irreversible scarring of the...

liver, the liver is incapable of processing blood from the bowels. As a result, an abnormally high pressure develops in the veins that drain blood from the bowels as the body tries to form other channels for the blood to empty into the main circulation. These channels consist of fragile veins that surround the esophagus, stomach, or other areas of the digestive tract. Because of the fragility of these veins, they are prone to rupturing, which can result in massive amounts of bleeding. The abnormally high pressure within the veins draining into the liver, called portal hypertension, can also result in the formation of fluid seeping from the surface of the liver and collecting in large quantities in the abdominal cavity, a condition known as ascites.

Massive internal bleeding caused by portal hypertension occurs in about 40% of patients with cirrhosis. It is initially fatal in at least half of these patients. Patients who survive are likely to experience bleeding recurrence. Portal vein bypass, also called portacaval shunting, is performed on these surviving patients to control bleeding.

The purpose of portal vein bypass surgery is to lower portal hypertension by shunting blood away from the portal venous system and into the main venous system.