Hepatic encephalopathy (HE) is a frequent complication of portosystemi
c 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 H
E by maintaining some prograde portal perfusion in most patients and p
reventing arterioportal blood flow which may be of disadvantage in mos
t conditions. On the other hand, a smaller shunt diameter limits the r
eduction 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 cl
ass, 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 th
is is not the case, the shunt diameter needs fine tuning with reductio
n in case of HE or functional deterioration, or enlargement if rebleed
ing 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 ov
er the surgical shunting procedures.