Transjugular intrahepatic portosystemic shunt and hepatic encephalopathy.
Hepatic encephalopathy (HE) is a frequent complication of portosystemic shunts with an incidence of about 25%. In side-to-side shunts, such as the transjugular intrahepatic portosystemic shunt (TIPS), there is relation between the incidence of postshunt HE and the diameter of the shunt. A smaller shunt with a diameter of < 8 mm has a lower risk of HE by maintaining some prograde portal perfusion in most patients and preventing arterioportal blood flow which may be of disadvantage in most conditions. On the other hand, a smaller shunt diameter limits the reduction in the portal-systemic pressure gradient and, therefore, may have a higher risk of rebleeding. The size of the shunt must be based on these risks which may be estimated by factors such as age, Child class, previous episodes of HE, size of varices and severity of previous bleedings. In retrospect, the decision for a specific diameter, i.e. pressure reduction, was right if the patient's liver function remained stable after TIPS, no HE occurred, and the varices disappeared. If this is not the case, the shunt diameter needs fine tuning with reduction in case of HE or functional deterioration, or enlargement if rebleeding occurred or the varices show a higher risk of such an event. This potential of fine tuning at any time is the major advantage of TIPS over the surgical shunting procedures.