Morphometric analysis of conformational changes in hepatic venous system after right lobe living donor liver transplantation

Aim: After living donor liver transplantation (LDLT), the graft liver regenerates to the standard liver volume. However, little is known about the influence of this phenomenon on the hepatic venous system. Methods: Fourteen right lobe LDLT without the middle hepatic vein were included in this study. Computed tomography before and 1 month after LDLT was performed to measure the inflow angle of the right hepatic vein (RHV), the aspect ratio of the inferior vena cava (IVC), the coordinate position of IVC and diameter of RHV. In addition, the regeneration index (RI) was determined on each liver segment. Results: RHV showed a clockwise rotation at early postoperative months, the average increase of the inflow angle being 14.5 +/- 15.6 (mean +/- standard deviation) degrees. IVC was shifted from right to left with a deformity to a long oval shape on horizontal sections. The center of IVC moved dorsally at an average of 0.55 +/- 0.77 cm and leftward at an average of 0.82 +/- 0.89 cm. Diameter of RHV decreased at an average of 0.65 +/- 0.39 cm at its root. The extent of liver regeneration was more prominent in the posterior segment as compared to the anterior segment, the average RI values being 1.65 +/- 0.65 and 1.17 +/- 0.44, respectively (P < 0.05). Hepatic vein outflow block (HVOB) was encountered in two patients with a marked conformational deformity observed in the hepatic venous system at early postoperative months after LDLT. Conclusion: After right lobe LDLT, the hepatic venous system exhibits a profound conformational change, which most likely plays a role in the onset of HVOB.