Definition of Hepatic vein obstruction (Budd-Chiari):

Hepatic vein obstruction refers to a blockage of the hepatic vein, which carries blood away from the liver.

Causes, incidence, and risk factors:

Hepatic vein obstruction prevents blood from flowing out of the liver and back to the heart. This blockage can cause liver damage. Obstruction of this vein can be caused by masses pressing on the vessel (tumor) or by thrombus (clot) formation within the vessel.

Most often, it is caused by conditions that increase the body's propensity to form blood clots. These include:

• Any of a number of hereditary or acquired clotting abnormalities
• Myeloproliferative disorders -- abnormal proliferation of cells from the bone marrow
• Chronic inflammatory or autoimmune diseases
• Cancers
• Oral contraceptives and pregnancy
• Infections