The hepatic circulation and portal hypertension

Pathophysiological abnormalities attendant to disorders of the hepatic circulation and portal hypertension are chiefly responsible for growing morbidity and mortality from diseases of the liver. Altered metabolism of drugs and foodstuffs, development of oesophageal varices, and a decrease in hepatocyte oxygenation represent the major untoward effects from functional and/or structural changes in the vascular bed of the liver. Clinical investigations of the hepatic circulation, including radiologic visualisation of the vascular bed, measurement of portal pressure and estimation of total hepatic and portal blood flow are desirable in all patients with cirrhosis and endoscopic evidence of oesophageal varices. These diagnostic studies increase therapeutic perspective and permit better selection of candidates for medical or surgical therapy. Special attention should be focused on maintaining adequate perfusion and oxygenation in treatment of liver disease and its complications. This requires attention to preserving substrates and enzymes necessary for adequate oxygen supply, avoidance of procedures or therapy which diminish portal or arterial blood flow, and avoiding injury which alters the microcirculation or interferes with hepatocyte uptake capacity.