Relationship between Hepatic Venous Anatomy and Blood Loss: Proposal of Vena Cava Half-Clamp with Trendelenburg Posture to Control Hepatic Venous Bleeding during Hepatectomy

Abstract

Introduction: Predicting increased blood loss based on anatomical intervascular relationships is essential in major hepatectomy to understand the mechanism of hepatic venous bleeding. Method: We assessed 63 consecutive patients undergoing anatomical hepatectomy exposing the hepatic vein (HV) trunk at two institutes. Correlations between anatomical alterations of the hepatic inferior vena cava (IVC), HV, hepatic IVC, or right atrium (RA) and the blood loss per standard weight (BLSW) or blood transfusion (n=18) were analyzed. The results of IVC partial clamping (PC) were additionally examined. Result: The BLSW in type V-up anatomical morphology was significantly higher than that in straight type (p<0.05). The parameters associated with an increased BLSW (>13.5 mL/kg) were tumour size (>4 cm), prothrombin activity (<87%), CVP (>7 mmHg), area of suprahepatic IVC (<360 mm2), IVC-RA gap (>28 mm), longitudinal angle of IVC (<160°), and axial angle of the MHV (<55°). Multivariate analysis revealed that a high IVC-RA gap was a significant independent risk factor (odds ratio; 4.3, p<0.05). Among 25 patients undergoing IVC-PC, only three showed a remarkable decrease in hepatic venous bleeding. Although IVC-PC led to a decrease in systolic arterial pressure and difficult to control systemic circulation in many cases, the combined Trenderenburg posture could solve this problem. Conclusions: The IVC-RA gap might be a promising novel predictive parameter reflecting increased blood loss leading to blood transfusion in anatomical hepatectomy. Further, in the case of increased IVC gap and hepatic venous bleeding is difficult, our proposal combined procedure is feasible、easy, safe and useful.