Section 10. Liver and Gallbladder Disorders

Chapter 138. Blood Vessel Disorders of the Liver

Topics: Introduction | Abnormalities of the Hepatic Artery | Veno-occlusive Disease | Budd-Chiari Syndrome | Portal Vein Thrombosis | Blood Vessel Disorders Resulting From Other Diseases

Abnormalities of the Hepatic Artery

The hepatic artery carries oxygen-rich blood to the liver from the heart or its branches. It is the main supply of blood and oxygen to the liver. The portal artery also supplies blood to the liver, helping ensure that this vital organ always receives enough blood.

Narrowing or Blockage: A narrowing or blockage can reduce the flow of blood through the hepatic artery. If this happens, blood flow to the liver is reduced. Narrowing or blockage of the hepatic artery can have various causes, including injuries, such as a gunshot wound or surgical trauma, or blood clots. Blood clots generally are caused by inflammation of the arterial wall (arteritis) or by an infusion of chemotherapy drugs or other toxic or irritating substances into the artery. Blockage of the hepatic artery can be detected using x-rays enhanced with the injection of radiopaque dye (arteriography) or through magnetic resonance angiography (MRA).

Reduced blood flow through the hepatic artery can be due to other causes as well, including shock (for example, due to heart failure, severe blood or body fluid loss, or infection) and sickle cell disease.

Because the liver has a dual blood supply, reduced blood flow through the hepatic artery usually does not damage the liver or causes only minor problems. However, severe damage to the liver resulting from reduced blood flow, called ischemic hepatitis, can occur in a person who has had a liver transplantation or a previous blood clot of the portal vein. Ischemic hepatitis is often of less immediate concern than are the problems resulting from the cause of the reduced blood flow, such as shock resulting from severe heart failure. Symptoms of ischemic hepatitis include nausea, vomiting, and liver enlargement and tenderness. Abnormal results of liver function tests help confirm the diagnosis. Treatment of ischemic hepatitis is concentrated on treating the underlying cause and thereby restoring blood flow to the liver. There is no specific treatment for the liver itself.

Unlike the liver, the large bile ducts outside the liver, such as the left and right hepatic ducts and the common bile duct, do not have a dual blood supply. They receive their blood exclusively from the hepatic artery. Thus, any obstruction of blood flow through the hepatic artery to the ducts can result in damage (ischemia), causing death of some of the cells forming the ducts. Death of some of the cells can result in a narrowing (stricture) of the affected bile duct, which leads to obstruction and may result in jaundice (a yellowish discoloration of the skin and the whites of the eyes). The obstruction is treated with endoscopic retrograde cholangiopancreatography (see Section 10, Chapter 134) and the insertion of a stent (stenting).

Aneurysms: An aneurysm is a bulge at a weak spot in an artery (see Section 3, Chapter 35); an aneurysm in the hepatic artery is usually caused by infection, atherosclerosis, injury, or polyarteritis nodosa (see Section 5, Chapter 69). An aneurysm that presses on a nearby bile duct may narrow or even block it, which then blocks bile flow from the liver. This blockage results in jaundice. An aneurysm may also bleed into a nearby bile duct. Unless treated, up to 75% of aneurysms of the hepatic artery rupture, often causing massive bleeding and possible death.

Imaging tests, such as x-rays enhanced by injection of a radiopaque dye (a dye visible on x-rays) in a technique called arteriography or computed tomography (CT) scanning enhanced by injection of a radiopaque dye, may be used to diagnose an aneurysm.

An aneurysm may be treated by inserting a catheter into the hepatic artery and injecting an irritating substance that causes a clot to form, thereby blocking the artery. If this procedure (called embolization) fails, surgery is performed to tie off (ligate) the artery directly.