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What is the Hepatic Portal Vein?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

The hepatic portal vein is a major blood vessel in the abdomen, acting as a collection point for blood from the digestive tract and routing this blood into the liver. Almost all the blood passing through the digestive tract ends up in this vein before being circulated back into the body, allowing the liver to filter the blood and remove toxins and begin metabolizing substances absorbed through the gastrointestinal tract. It is important to note that despite the name, this structure is not a true vein in the anatomical sense, as it does not return blood to the heart.

People may refer generally to the hepatic portal vein as simply “the portal vein,” although it is not the only portal vein in the body. A number of smaller blood vessels act as tributaries to feed this vein, including the splenic vein and the superior mesenteric vein. These vessels join together to form the short, thick hepatic portal vein, and the vein splits, feeding the blood to various regions of the liver for processing. Blood drains from the liver through the hepatic vein, and this blood will be purified, as it has already gone through metabolism in the liver.

The hepatic portal vein routs blood into the liver.
The hepatic portal vein routs blood into the liver.

The phenomenon of processing blood in the liver is known as the first pass effect. Certain medications cannot be ingested because when they are absorbed through the intestines, the liver processes them and renders them useless. These medications must be administered in other ways, such as intravenously, transdermally, or through direct absorption in the mucus membranes, so they bypass the liver's metabolism, giving them a chance to act in the body.

The term hepatic refers to the liver.
The term hepatic refers to the liver.

Numerous health conditions can involve the hepatic portal vein and disorders of this vein can be associated with serious medical issues. Cirrhosis commonly leads to portal hypertension, a rise in blood pressure in this vessel that can have dangerous consequences for the patient. Among other things, patients with liver problems can develop ascites, which are buildups of fluid in the abdomen, as a result of complications involving the hepatic portal vein.

Almost all blood that passes through the gastrointestinal tract ends up in the hepatic portal vein before being circulated back into the body.
Almost all blood that passes through the gastrointestinal tract ends up in the hepatic portal vein before being circulated back into the body.

This vein can be visualized during surgical procedures involving the liver and may be visible on medical imaging studies as well. Assessing portal vein health may be recommended in cases where a doctor suspects a patient has portal hypertension or another problem. In patients where liver damage is contributing to problems with this vein, controlling the liver condition is necessary to give the vein an opportunity to recover.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a WiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

cloudel

I can think of a few inhaled drugs that don't have to pass through the hepatic portal system. One is asthma medication, which is administered through an inhaler. Another is a kind of allergy medication that comes in the form of a nasal spray.

I'm guessing that these provide more direct relief than pills that have to pass through the liver before they can take effect. Maybe this kind of medicine would be rendered ineffective by the liver.

I do know that hydrocodone has to pass through the liver to be activated. This powerful painkiller takes around 30 to 45 minutes to take effect, and this is because it has to travel through the hepatic portal vein.

shell4life

I have a friend who caught a rare tropical disease while swimming in water infected with a parasite that came from freshwater snails. She was on vacation in the Caribbean, and she didn't know the water was contaminated.

The disease is called schistosomiasis, and it caused her to develop portal hypertension. The parasites entered her body and developed into worms inside her blood vessels. These worms laid eggs, and they got lodged inside, blocking her blood flow.

She had the disease for years before it caused liver problems. Her doctor prescribed an anti-worm medication often used in animals. She only had to take it for two days, and it worked. Her portal hypertension went away soon thereafter.

orangey03

@OeKc05 – Portal hypertension is pretty serious stuff. My dad suffered from confusion and forgetfulness, and though we figured this was just because he was aging, the doctor said that his poor liver function was causing it.

The doctor recommended that he lower his protein and sodium intake. This would help with the confusion.

After banding and drug therapy failed to help him, the doctor decided to put a stent in his liver. The tube went right in the middle of the organ, and it connected the portal vein to the hepatic vein.

The stent helped, but we were about to give up hope before that. It was scary to see my dad not responding to treatment.

OeKc05

My uncle had a problem with alcohol that caused liver damage. He developed cirrhosis of the liver and portal hypertension because of his constant drinking.

The blood vessels leading to his liver were blocked, so the blood got backed up and flowed back to his heart and then to his lungs. He started having tarry stools full of blood, and he accumulated a lot of fluid in his abdomen.

He had surgery, and the doctor put rubber bands around blood vessels to block them off, because several of them had ruptured and were bleeding. The doctor also gave him a nonselective beta blocker to treat the hypertension.

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    • The hepatic portal vein routs blood into the liver.
      By: Marcelo Reis
      The hepatic portal vein routs blood into the liver.
    • The term hepatic refers to the liver.
      By: nerthuz
      The term hepatic refers to the liver.
    • Almost all blood that passes through the gastrointestinal tract ends up in the hepatic portal vein before being circulated back into the body.
      By: maya2008
      Almost all blood that passes through the gastrointestinal tract ends up in the hepatic portal vein before being circulated back into the body.
    • Cirrhosis commonly leads to portal hypertension.
      By: peterjunaidy
      Cirrhosis commonly leads to portal hypertension.