Doppler sonography findings associated with transjugular intrahepatic portosystemic shunt malfunction

OBJECTIVE. Our purpose was to determine the overall accuracy of Doppler sonography and the accuracy of specific Doppler parameters associated with a compromised transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS. For 43 patients who had undergone TIPS, 64 correlated sonogram- venogram paired examinations were analyzed. Sonographic parameters assessed included absolute velocities plus absolute and percentage changes in velocities measured in the main portal vein (MPV) and in several intrashunt locations (including peak and minimum velocity). Direction of flow and change in direction of flow in the left and right portal veins were also examined, TIPS malfunction was defined as any shunt with greater than or equal to 50% stenosis or any stenosis with a portosystemic gradient greater than 15 mm Hg. RESULTS. The prospective interpretation of the sonograms using all available parameters resulted in a sensitivity of 92% and a specificity of 72% for detecting TIPS malfunction. Peak shunt velocity (absolute velocity and velocity change), distal shunt velocity, MPV velocity (absolute velocity and percentage change in velocity), change in minimum shunt velocity, and direction of flow in branch portal veins were found to have statistically significant differences between normal and abnormal shunts. Sensitivities for these individual parameters ranged from 64% to 84%, and specificities ranged from 70% to 100%. When either the MPV velocity or the distal shunt velocity was abnormal, the sensitivity was 94%. When both parameters were abnormal, the specificity for detecting TIPS malfunction was 100%. CONCLUSION. Doppler sonography is a sensitive and relatively specific means of revealing TIPS malfunction. Accuracy depends on analysis or multiple sonographic parameters.