Impact of the inferior vena cava morphology on fluid dynamics of the hepatic veins.

We reported previously that a large vertical interval between the hepatic segment of the inferior vena cava (IVC) and right atrium (RA), referred to as the IVC-RA gap, was associated with more intraoperative bleeding during hemi-hepatectomy. We conducted a computational fluid dynamics (CFD) study to clarify the impact of fluid dynamics resulting from morphologic variations around the liver. The subjects were 10 patients/donors with a large IVC-RA gap and 10 patients/donors with a small IVC-RA gap. Three-dimensional reconstructions of the IVC and hepatic vessels were created from CT images for the CFD study. Median pressure in the middle hepatic vein was significantly higher in the large-gap group than in the small-gap group (P = 0.008). Differences in hepatic vein pressure caused by morphologic variation in the IVC might be one of the mechanisms of intraoperative bleeding from the hepatic veins.