Intrahepatic hemodynamic changes following portal vein embolization: a prospective Doppler study

The aim of this study was to describe the intrahepatic hemodynamic modifications induced by right portal vein embolization (RPVE) using Doppler ultrasound. Eighteen patients with hepatocellular carcinoma (n = 8), liver metastases (n = 9), or multiple adenomas, underwent RPVE 1 month before right hepatectomy in order to increase the size of future remnant liver. Doppler ultrasound was performed before and 1 month after RPVE. The portal vein flow and the hepatic artery resistive index in right and left lobes (segments V and III) were calculated. We recorded simultaneously artery and portal vein of segment III to measure the arterioportal ratio calculated as follows: (maximal arterial systolic velocity minus maximal portal vein velocity)/maximal arterial systolic velocity. Results were compared in cirrhotic patients (group A) and in healthy liver patients (group B). In both groups, portal flow was not significantly modified following RPVE. In the left lobe, in both groups the hepatic artery resistive index was not significantly modified. In group B, the arterioportal ratio decreased significantly (0.71 +/- 0.18 and 0.42 +/- 0.23, respectively, before and after embolization; p < 0.01), whereas it was not statistically modified in group A (0.75 +/- 0.17 and 0.69 +/- 0.14, respectively, before and after embolization). The right hepatic arterial resistive index decreased significantly in both groups after embolization (0.74 +/- 0.07 to 0.66 +/- 0.07, p<0.05; and 0.66 +/- 0.07 to 0.61 +/- 0.06, p < 0.05, respectively, before and after RPVE for groups A and B). Total portal flow was unchanged after RPVE (750 +/- 337 ml/mn and 696 +/- 231 ml/mn, respectively, before and after RPVE). The hepatic artery resistive index was unchanged before and after embolization in the left lobe (0.75 +/- 0.13 and 0.74 +/- 0.14, respectively), but significantly decreased in the right lobe (0.7 +/- 0.08 and 0.62 +/- 0.06 respectively, p < 0.05). The left arterioportal ratio decreased significantly from 0.76 +/- 0.17 to 0.52 +/- 0.23 after PVE, p < 0.02). Our study confirms that right portal occlusion induces a decrease in hepatic artery resistive index in the right lobe and does not modify total portal flow. The left and right lobes of the liver have separate arterioportal regulation.