Portal hypertension is an increased pressure in the portal venous system. A better way to measure the portal venous system is to measure the pressure ladder between the portal vein and the inferior vena cava, with a normal value of less than 5 mmHg. This pressure represents the perfusion pressure between the true portal and hepatic venous circulation, which is a high blood flow low resistance system under normal conditions. In cirrhosis, the vascular resistance in the liver increases and the return of blood from the viscera will be impeded and will have to be returned to the body circulatory system (heart) through vessels with low resistance. The most important collateral circulation system in patients with cirrhotic portal hypertension is the collateral circulation of the lower esophageal segment of the fundus of the stomach, where in severe cases the vessels dilate and thin and rupture and bleed. Measurement of the hepatic venous pressure ladder is very helpful in determining prognosis and guiding treatment.