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Portal hypertension: at the bedside
Published on November 30, 2022 55 min
A selection of talks on Physiology & Anatomy
Hello, my name is Clara Tow and I am a transplant hepatologist at the Montefiore Medical Center, Albert Einstein College of Medicine in New York City. It gives me great pleasure to talk to you today about portal hypertension at the bedside.
In this talk, we will be reviewing many aspects of portal hypertension. I think it's important to understand the anatomy of the portal circulation and talk about what is normal before we define what is abnormal. We will discuss how portal hypertension develops, the different complications that can occur and end on a discussion about the best treatments we have for this disease process.
The liver is a very complex organ, if I had to summarize it, I would say that it was a metabolically active filter. Because it is this filter, blood flow through it is really key. It's all about how the blood interacts with the liver and the individual cells, and how that blood flow allows the liver to do all the activities it's supposed to do.
The liver is a very unique organ because it has a dual vascular supply. It has a hepatic artery that delivers highly oxygenated blood to this organ. This is a very classic arterial system. The liver also has a portal vein, which delivers partially oxygenated blood to the liver. It is responsible for about 20% of the total oxygen delivery. The blood from the portal vein is derived from draining veins throughout the GI tract and spleen, and they eventually converge to form the portal vein. As the blood moves through the liver, it goes through smaller and smaller channels until we get to the most microscopic level where blood is literally flowing between sheets of hepatocytes. Then they begin to converge into the outflow track, which is what we call the hepatic vein. The veins draining from the GI tract and the spleen, the portal vein, the flow of blood through the liver and eventually leaving the liver through the hepatic vein. This is what we call portal circulation.