A portacaval shunt is a treatment for high blood pressure in the liver. A connection is made between the portal vein, which supplies 75% of the liver's blood, and the inferior vena cava

Inferior vena cava

The inferior vena cava , also known as the posterior vena cava, is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart....

, the vein that drains blood from the lower two-thirds of the body. The most common causes of liver disease resulting in portal hypertension

Portal hypertension

In medicine, portal hypertension is hypertension in the portal vein and its tributaries.It is often defined as a portal pressure gradient of 10 mmHg or greater.-Causes:Causes can be divided into prehepatic, intrahepatic, and posthepatic...

 are cirrhosis

Cirrhosis

Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules , leading to loss of liver function...

 caused by alcohol abuse

Alcohol abuse

Alcohol abuse, as described in the DSM-IV, is a psychiatric diagnosis describing the recurring use of alcoholic beverages despite negative consequences. Alcohol abuse eventually progresses to alcoholism, a condition in which an individual becomes dependent on alcoholic beverages in order to avoid...

 and viral hepatitis

Viral hepatitis

Viral hepatitis is liver inflammation due to a viral infection. It may present in acute or chronic forms. The most common causes of viral hepatitis are the five unrelated hepatotropic viruses Hepatitis A, Hepatitis B, Hepatitis C, Hepatitis D, and Hepatitis E...

 (hepatitis B and C). Less common causes include diseases such as hemochromatosis, primary biliary cirrhosis

Primary biliary cirrhosis

Primary biliary cirrhosis, often abbreviated PBC, is an autoimmune disease of the liver marked by the slow progressive destruction of the small bile ducts within the liver. When these ducts are damaged, bile builds up in the liver and over time damages the tissue. This can lead to scarring,...

 (PBC), and portal vein thrombosis

Portal vein thrombosis

Portal vein thrombosis is a form of venous thrombosis affecting the hepatic portal vein, which can lead to portal hypertension and reduction in the blood supply to the liver.-Causes:...

.

Cirrhotic patients with portacaval shunts who have esophageal varices

Esophageal varices

In medicine , esophageal varices are extremely dilated sub-mucosal veins in the lower esophagus...

 (or any upper GI bleed) can suffer ammonium intoxication

Hepatic encephalopathy

Hepatic encephalopathy is the occurrence of confusion, altered level of consciousness and coma as a result of liver failure. In the advanced stages it is called hepatic coma or coma hepaticum...

which may lead to coma.