What is "portal hypertension"

n. increase in blood pressure in the veins of the portal system caused by obstruction in the liver (often associated with alcoholic cirrhosis), causing enlargement of the spleen and collateral veins

Portal hypertension is hypertension (high blood pressure) in the hepatic portal system, which is composed of the portal vein and its branches and tributaries. Portal hypertension is defined as elevation of hepatic venous pressure gradient. In clinical practice the pressure is not measured directly until the decision to place a transjugular intrahepatic portosystemic shunt has been made. Part of the procedure, a hepatic vein wedge pressure is measured with the assumption of no pressure drop across the liver yielding portal vein pressure.