Sonography of transjugular intrahepatic portosystemic shunts.

Transjugular intrahepatic portosystemic shunting (TIPS) is an effective procedure for relieving portal hypertension. Sonography can usefully assist portal vein puncture. Color and duplex sonography after TIPS demonstrates changes in hepatic vascular hemodynamics, detects complications, and confirms shunt patency. A large proportion of shunts will develop progressive stenosis over 12 months. Stenosis occurs because of pseudointimal hyperplasia in the stent or in the hepatic vein. Patent shunts are characterized by velocities in excess of 70 cm/s and hepatofugal flow in the portal circulation distal to the shunt. Although the cause of the stenosis can rarely be seen, velocities of less than 50 cm/s indicate shunt stenosis. Loss of cardiac pulsatility is another useful sign of shunt stenosis. Regular sonographic monitoring reliably detects stenosis, allowing stent revision and preventing recurrence of bleeding.