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A portacaval anastomosis or portocaval anastomosis is a specific type of circulatory anastomosis that occurs between the veins of the portal circulation and the vena cava, thus forming one of the principal types of portasystemic anastomosis or portosystemic anastomosis, as it connects the portal circulation to the systemic circulation, providing an alternative pathway for the blood.
Portacaval anastomosis, by contrast, is a veno-venous anastomosis between a vein of the portal circulation and a vein of the systemic circulation, which allows blood to bypass the liver in patients with portal hypertension, often resulting in hemorrhoids, esophageal varices, or caput medusae.
Portacaval anastomosis, by contrast, is an anastomosis between a vein of the portal circulation and a vein of the systemic circulation, which allows blood to bypass the liver in patients with portal hypertension, often resulting in hemorrhoids, esophageal varices, or caput medusae. [citation needed]
The bare area of the liver is clinically important because of the portacaval anastomosis. It is a site where infection can spread from the abdominal cavity to the thoracic cavity . It encloses the right extraperitoneal subphrenic space.
A portacaval shunt, portocaval shunt, or portal-caval shunt is a surgical procedure where a connection (a shunt) is made between the portal vein and the inferior vena cava. Under normal circumstances, the portal vein drains blood from the abdomen to the liver.
The superficial epigastric vein drains to the femoral vein which ultimately drains into the inferior vena cava directly through the external iliac and common iliac vein, thereby bypassing the liver. Dilation of this particular portacaval anastomosis results in what is referred to as caput medusae.
Portal hypertension is defined as increased portal venous pressure, with a hepatic venous pressure gradient greater than 5 mmHg. [3] [4] Normal portal pressure is 1–4 mmHg; clinically insignificant portal hypertension is present at portal pressures 5–9 mmHg; clinically significant portal hypertension is present at portal pressures greater than 10 mmHg. [5]
Esophageal varices and gastric varices result from collateral circulation in the esophagus and stomach (a process called portacaval anastomosis). [41] When the blood vessels in this circulation become enlarged, they are called varices. Varices are more likely to rupture at this point. [9] Variceal rupture often leads to severe bleeding, which ...