The Cross-Sectional Area Ratio of Right-to-Left Portal Vein Predicts the Effect of Preoperative Right Portal Vein Embolization

Background and Objectives: Preoperative right portal vein embolization (RPVE) is often attempted before right hepatectomy for liver tumors to increase the future remnant liver volume (FRLV). Although many factors affecting FRLV have been discussed, few studies have focused on the ratio of the cross-sectional area of the right portal vein to that of the left portal vein (RPVA/LPVA). The aim of the present study was to evaluate the effect of RPVA/LPVA on predicting FRLV increase after RPVE. Materials and Methods: The data of 65 patients who had undergone RPVE to increase FRLV between 2004 and 2021 were investigated retrospectively. Using computed tomography scans, we measured the total liver volume (TLV), FRLV, the proportion of FRLV relative to TLV (FRLV%), the increase in FRLV% (Delta FRLV%), and RPVA/LPVA twice, immediately before and 2-3 weeks after RPVE; we analyzed the correlations among those variables, and determined prognostic factors for sufficient Delta FRLV%. Results: Fifty-four patients underwent hepatectomy. Based on the cut-off value of RPVA/LPVA, the patients were divided into low (RPVA/LPVA <= 1.20, N = 30) and high groups (RPVA/LPVA > 1.20, N = 35). The Delta FRLV% was significantly greater in the high group than in the low group (9.52% and 15.34%, respectively, p < 0.001). In a multivariable analysis, RPVA/LPVA (HR = 20.368, p < 0.001) was the most significant prognostic factor for sufficient Delta FRLV%. Conclusions: RPVE was more effective in patients with higher RPVA/LPVA, which is an easily accessible predictive factor for sufficient Delta FRLV%.