Doppler estimation of portal blood flow after percutaneous transhepatic portal vein embolization

Objective To elucidate changes in portal blood flow (PBF) after percutaneous transhepatic portal vein embolization and their possible association with hypertrophy of the nonembolized hepatic segments. Summary Background Data The increase in PBF of the nonembolized hepatic segments after embolization is presumed to trigger hypertrophy of these segments. However, changes in PBF after embolization have not been investigate, and their extent remains unknown. Methods The authors prospectively measured PBF velocity, using color Doppler ultrasound, in 21 patients without cirrhosis who underwent embolization of the right portal vein or the right portal vein plus the left medial portal branch. Liver hypertrophy was assessed with a volumetric study using computed tomography. Results The PBF velocity significantly increased, from 11.1 +/- 3.6 cm/sec before embolization to 20.1 +/- 7 cm/sec 1 day after embolization. Subsequently, the velocity gradually decreased, but it remained significantly elevated until postembolization day 14. The volume of the nonembolized segments significantly increased from 370 +/- 141 cm(3) to 488 +/- 145 cm(3). the hypertrophy rate (cm(3)/day) of the nonembolized segments after embolization correlated closely with the extent of increase in the PBF velocity, expressed as the velocity on day 1 divided by the velocity before embolization. The hypertrophy rate had a significant correlation with the absolute value of the PBF velocity on day 1, but its correlation coefficient was low. No significant correlations were observed between the hypertrophy rate and other clinical variables. Conclusions The hypertrophy rate of nonembolized hepatic segments after embolization is predictable from the extent of the increase in the PBF velocity. This can be estimated easily and noninvasively with Doppler ultrasound 1 day after embolization.