Pressures in the IVC and portal vein are measured with a saline (spinal) manometer by direct needle puncture before performance of the portacaval anastomosis. For all pressure measurements, the bottom of the manometer is positioned at the level of the IVC, which is marked on the skin surface of the body with a towel clip (A-1 to A-5). All portal pressures are corrected by subtracting the IVC pressure from the portal pressure. A portal vein-IVC pressure gradient, also known as the corrected free portal pressure, of 150 mm saline or higher, represents clinically significant portal hypertension. Most patients with bleeding esophageal varices have a portal vein-IVC gradient of 200 mm saline or higher. The pressure measurements include:
■ IVCP - inferior vena caval pressure
■ FPP - free portal pressure
■ HOPP - hepatic occluded portal pressure, obtained on the hepatic side of a clamp occluding the portal vein
■ SOPP - splanchnic occluded portal pressure, obtained on the intestinal side of a clamp occluding the portal vein
In normal humans, HOPP is much lower than FPP, and SOPP is much higher. In patients with portal hypertension, the finding of an HOPP that is higher than the FPP suggests the possibility that blood flow in the portal vein is reversed because of severe hepatic outflow obstruction.
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...