ABSTRACT
Portal hypertension is defined as the elevation of portal venous pressure above 12mmHg. The portal pressure is more accurately measured in relation to the inferior vena caval pressure, and portal hypertension is considered present if the difference between portal pressure and caval pressure (knownas the corrected portal pressure) exceeds 11mmHg (150mm saline).[1] In clinical practice, however, portal hypertension is usually recognized by the pathologic disturbances it produces, including esophageal varices and splenomegaly, and in the presenceof underlying liver disease, portal hypertension usually contributes to the development of ascites and liver cell failure.
Portal hypertension is generally the result of obstruction of the portal blood flow.Very rarely, portal hypertension occurs due to increased portal flow as a result of a splanchnic arteriovenous fistula. Portal hypertension is classically divided into two major categories, depending onwhether the obstruction to flow occurs before the level of the hepatic sinusoids (presinusoidal portal hypertension) or at or beyond the sinusoids (sinusoidal or postsinusoidal portal hypertension). The clinical implication of this distinction is related to the fact that, unlike sinusoidal or postsinusoidal causes of portal hypertension, the liver function in presinusoidal portal hypertension is usually well preserved until the very late stages of the disease. These patients thus tolerate the complications of the disease as well as the interventions needed quite well.
