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GENERAL CONSIDERATION AND HISTORY
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The history of portal hypertension is intriguing. It is believed that Leonardo Vinci was the first to describe portal hypertension in the fifteenth century. However, Leonardo thought that the changes in the portal vein that becomes large and tortuous cause the changes in the liver, which he described as “liver dires and liver becomes as a frozen bran in color and consistency.”
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In 1543, Andreas van Wesel (Vesalio in Latin) demonstrated that the blood comes from the heart and not from the liver. He described with a great deal of accuracy the portal system. He described a case of bleeding hemorrhoids which he attributed to the dilatation of the portal branches. Later on, Glisson of London in the seventeenth century demonstrated the details of the portal circulation.1 The term cirrhosis was mentioned in 1819 by Renee Laennes of Paris. The word cirrhosis is derived from two Greek words: Skirros (Hard fibrotic) and Kirrhos (yellowish).2 While most of the work was focusing on liver cirrhosis, Augustine Gilbert in Paris introduced the term “portal hypertension” and he described with some details the enlargement of the natural collaterals between the portal and the venous system including the esophageal veins.3 The portal pressure was measured for the first time by Thompson in 1937, who directly measured the pressure in the portal vein in an open abdomen.4
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Blood flow to the liver is provided through both the portal vein and hepatic artery. The portal vein provides approximately 75% of the 1500 mL of blood entering liver each minute. Despite being largely deoxygenated blood, its high flow provides 50% to 70% of the liver’s oxygen. The lack of valves in the portal venous system makes it possible to accommodate high flow at low pressure due to low resistance. Additionally, this allows for the measurement of portal venous pressure at any point along the portal venous system.5 The common hepatic artery provides about 25% of the blood supply to the liver. The hepatic artery arises from the celiac axis and ascends in the hepatoduodenal ligament, then gives the right gastric, gastroduodenal and proper hepatic artery before it divides into right and left hepatic arterial branches in the liver hilum. There are common variations including a replaced right hepatic artery arising from the superior mesenteric artery in 9.6%, and left hepatic artery originating from the left gastric artery (6.6%). In 2.6%, the common hepatic artery has a variant anatomy originating from the superior mesenteric artery and from the aorta. Other anatomical variations include the right hepatic artery arising from the celiac artery (1.8%) and aorta (0.5%).6
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The portal vein is formed at the level of the second lumber vertebra behind the pancreas. The length of the vein is about 6 to 9 cm reaching the hilum of the liver where it divides into the right ...