Sonography of Transjugular Intrahepatic Portosystemic Shunts: Detection of Elevated Portosystemic Gradients and Loss of Shunt Function

Abstract

To evaluate the role of ultrasound (US) in the detection of elevated portosystemic gradients and loss of shunt function in patients with a transjugular intrahepatic portosystemic shunt (TIPS). The authors' prospectively compared 151 Doppler hepatic sonograms with follow-up portal venograms in 64 patients with TIPS. Sonographic data from within the portal system, hepatic arteries, and three areas within the TIPS were collected. Statistical analysis of these parameters was used to establish the US criteria for shunt dysfunction. Midshunt velocity thresholds of less than 50 and less than 60 cm/sec yielded sensitivities and specificities of 46% and 93%, and 57% and 89%, respectively, for the detection of portosystemic gradients exceeding 15 mm Hg. Use of a threshold midshunt velocity of less than 60 cm/sec or main portal vein velocity of less than 40 cm/sec raised the shunt dysfunction detection sensitivity to 86%, with a specificity of 54%. Doppler US is an effective noninvasive screening tool for detecting elevated portosystemic gradients and evaluating the functional status of a TIPS. Midshunt velocities of less than 60 cm/sec or main portal vein velocities less than 40 cm/sec are a useful threshold for detecting shunt dysfunction.