|
Transjugular intrahepatic portosystemic shunt or transjugular intrahepatic portosystemic stent shunting (commonly abbreviated as TIPS or TIPSS) is an artificial channel within the liver that establishes communication between the inflow portal vein and the outflow hepatic vein. It is used to treat portal hypertension (which is often due to liver cirrhosis) which frequently leads to intestinal bleeding, life-threatening esophageal bleeding (esophageal varices) and the buildup of fluid within the abdomen (ascites). An interventional radiologist creates the shunt using an image-guided endovascular (via the blood vessels) approach, with the jugular vein as the usual entry site. The procedure was first described by Josef Rösch in 1969 at Oregon Health and Science University. It was first used in a human patient by Dr. Ronald Colapinto, of the University of Toronto, in 1982, but did not become reproducibly successful until the development of endovascular stents in 1985. In 1988 the first successful TIPS was realized by M. Rössle, G.M. Richter, G. Nöldge and J. Palmaz at the University of Freiburg. The procedure has since become widely accepted as the preferred method for treating portal hypertension that is refractory to medical therapy, replacing the surgical portocaval shunt in that role. ==Mechanism of action== Portal hypertension, an important consequence of liver disease, results in the development of significant collateral circulation between the portal system and systemic venous drainage (porto-caval circulation). Portal venous congestion causes venous blood leaving the stomach and intestines to be diverted along auxiliary routes of lesser resistance in order to drain to systemic circulation. With time, the small vessels that comprise a collateral path for porto-caval circulation become engorged and dilated. These vessels are fragile and often hemorrhage into the GI tract. (''See esophageal, gastric, rectal varices''). A TIPS procedure decreases the effective vascular resistance of the liver through the creation of an alternative pathway for portal venous circulation. By creating a shunt from the portal vein to the hepatic vein, this intervention allows portal blood an alternative avenue for draining into systemic circulation. In bypassing the flow-resistant liver, the net result is a reduced pressure drop across the liver and a decreased portal venous pressure. Decreased portal venous pressure in turn lessens congestive pressures along veins in the intestine so that future bleeding is less likely to occur. The reduced pressure also makes less fluid develop, although this benefit may take weeks or months to occur. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Transjugular intrahepatic portosystemic shunt」の詳細全文を読む スポンサード リンク
|