Portal hypertension: state of the art

In the last decade, the knowledge of the pathogenesis of portal hypertensio n has increased dramatically. Indeed, apart from the well-known pathogeneti c importance of structural factors, the role of vasoactive factors, which e nhance the increase in intrahepatic resistance, has been highlighted. The t wo pathogenetic factors of portal hypertension are: the increase in portal outflow resistance and an increase in splanchnic bloodflow, which worsens a nd maintains the increased increased pressure in the portal vein. The incre ase in portal inflow is part of the hyperdynamic circulatory syndrome, whic h is a haemodynamic characteristic of cirrhotic patients, In portal hyperte nsive patients, almost all the known vasoactive systems/substances are acti vated or increased and the most recent studies have stressed the importance of the endothelial factors, such as endothelins, nitric oxide and prostagl andins. Knowledge of the haemodynamic mechanisms allows a pathogenetic appr oach to the treatment of portal hypertension, particularly as far as medica l therapy is concerned. The main categories of drugs used are: the vasocons trictors (i.e., vasopressin, glypressin, somatostatin, non-selective beta-b lockers), which act by decreasing portal inflow, and the vasodilators (i.e. , nitroderivatives), which act mainly by decreasing intrahepatic portal res istance. Moreover, technological developments have introduced new tools for diagnosis, such as echo-colour-Doppler; and therapy, like variceal banding and transjugular intrahepatic porto-systemic shunt.