Extrahepatic portal vein obstruction

Abstract

Extrahepatic portal vein obstruction (EHO) is a disease presenting portal hypertension caused by the obliteration of the prehepatic portion of the portal vein, including the branches at the hepatic hilum. Secondary portal vein thrombosis with diverse background diseases is considered to make an occlusion of the portal vein which leads to the development of EHO. The basic pathophysiology of EHO includes portal hypertension due to prehepatic block of portal blood flow and well-preserved liver function without development of cirrhotic changes of the liver. Furthermore, cavernomatous transformation of the portal vein (CTPV), which is a consequence of the development of hepatopetal collateral vessels around the obliterated portal vein, is directly associated with the pathophysiology of EHO and contributes to the image diagnosis of the disease. Chronic or refractory ascites is uncommon compared with patients with liver cirrhosis. Some patients show biliary symptoms due to CTPV around the bile duct which is called portal biliopathy. Indications and methods for the treatment of gastroesophageal varices and hypersplenism are the same as those for portal hypertension with other causes. For symptomatic portal biliopathy, endoscopic or intervention radiology management is employed. For complete reduction of elevated portal pressure, trials of stent placement over the obstructed portal vein with intervention radiology have been reported, although clinical experience is limited. The overall prognosis is usually good except in patients with severe portal biliopathy or uncontrollable gastrointestinal varices.