Budd-Chiari Syndrome: A condition in which the hepatic venous outflow is obstructed anywhere from the small HEPATIC VEINS to the junction of the INFERIOR VENA CAVA and the RIGHT ATRIUM. Usually the blockage is extrahepatic and caused by blood clots (THROMBUS) or fibrous webs. Parenchymal FIBROSIS is uncommon.Vena Cava, Inferior: The venous trunk which receives blood from the lower extremities and from the pelvic and abdominal organs.Hepatic Veins: Veins which drain the liver.Portasystemic Shunt, Transjugular Intrahepatic: A type of surgical portasystemic shunt to reduce portal hypertension with associated complications of esophageal varices and ascites. It is performed percutaneously through the jugular vein and involves the creation of an intrahepatic shunt between the hepatic vein and portal vein. The channel is maintained by a metallic stent. The procedure can be performed in patients who have failed sclerotherapy and is an additional option to the surgical techniques of portocaval, mesocaval, and splenorenal shunts. It takes one to three hours to perform. (JAMA 1995;273(23):1824-30)Portasystemic Shunt, Surgical: Surgical venous shunt between the portal and systemic circulation to effect decompression of the portal circulation. It is performed primarily in the treatment of bleeding esophageal varices resulting from portal hypertension. Types of shunt include portacaval, splenorenal, mesocaval, splenocaval, left gastric-caval (coronary-caval), portarenal, umbilicorenal, and umbilicocaval.Phlebography: Radiographic visualization or recording of a vein after the injection of contrast medium.Portacaval Shunt, Surgical: Surgical portasystemic shunt between the portal vein and inferior vena cava.Syndrome: A characteristic symptom complex.Behcet Syndrome: Rare chronic inflammatory disease involving the small blood vessels. It is of unknown etiology and characterized by mucocutaneous ulceration in the mouth and genital region and uveitis with hypopyon. The neuro-ocular form may cause blindness and death. SYNOVITIS; THROMBOPHLEBITIS; gastrointestinal ulcerations; RETINAL VASCULITIS; and OPTIC ATROPHY may occur as well.Portal Vein: A short thick vein formed by union of the superior mesenteric vein and the splenic vein.Echinococcosis, Hepatic: Liver disease caused by infections with parasitic tapeworms of the genus ECHINOCOCCUS, such as Echinococcus granulosus or Echinococcus multilocularis. Ingested Echinococcus ova burrow into the intestinal mucosa. The larval migration to the liver via the PORTAL VEIN leads to watery vesicles (HYDATID CYST).Splenic Vein: Vein formed by the union (at the hilus of the spleen) of several small veins from the stomach, pancreas, spleen and mesentery.Radiography, Abdominal: Radiographic visualization of the body between the thorax and the pelvis, i.e., within the peritoneal cavity.Liver Transplantation: The transference of a part of or an entire liver from one human or animal to another.Technetium Tc 99m Sulfur Colloid: A gamma-emitting radionuclide imaging agent used for the diagnosis of diseases in many tissues, particularly in the gastrointestinal system, liver, and spleen.Venous Pressure: The blood pressure in the VEINS. It is usually measured to assess the filling PRESSURE to the HEART VENTRICLE.Mesenteric Veins: Veins which return blood from the intestines; the inferior mesenteric vein empties into the splenic vein, the superior mesenteric vein joins the splenic vein to form the portal vein.Angioplasty, Balloon: Use of a balloon catheter for dilation of an occluded artery. It is used in treatment of arterial occlusive diseases, including renal artery stenosis and arterial occlusions in the leg. For the specific technique of BALLOON DILATION in coronary arteries, ANGIOPLASTY, BALLOON, CORONARY is available.Iliac Vein: A vein on either side of the body which is formed by the union of the external and internal iliac veins and passes upward to join with its fellow of the opposite side to form the inferior vena cava.Ascites: Accumulation or retention of free fluid within the peritoneal cavity.Venous Thrombosis: The formation or presence of a blood clot (THROMBUS) within a vein.Liver Circulation: The circulation of BLOOD through the LIVER.Anticoagulants: Agents that prevent clotting.Methods: A series of steps taken in order to conduct research.Myeloproliferative Disorders: Conditions which cause proliferation of hemopoietically active tissue or of tissue which has embryonic hemopoietic potential. They all involve dysregulation of multipotent MYELOID PROGENITOR CELLS, most often caused by a mutation in the JAK2 PROTEIN TYROSINE KINASE.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Factor V: Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor V accomplishes this by forming a complex with factor Xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor V leads to Owren's disease.