Impact of the course of the segment 4 hepatic artery on proximal ductal margin status in right hepatectomy for perihilar cholangiocarcinoma

Background: The relationship between the course of the segment 4 hepatic artery and proximal ductal margin status in the right hepatectomy (H15678-B) for perihilar cholangiocarcinoma is unclear. This study aimed to evaluate proximal ductal margin status according to the course of the segment 4 hepatic artery in patients with perihilar cholangiocarcinoma treated with right hepatectomy. Methods: Consecutive patients with perihilar cholangiocarcinoma who underwent a right hepatectomy between January 2006 and August 2021 were retrospectively reviewed. The course of the segment 4 hepatic artery was classified based on the positional relationship with the umbilical portion of the left portal vein into R-UP and L-UP types. The R-UP type had the segment 4 hepatic artery running along the right caudal position of the umbilical portion of the left portal vein, whereas the L-UP type had the segment 4 hepatic artery running along the left cranial position of the umbilical portion of the left portal vein, with or without another branch running along the right caudal position of the umbilical portion of the left portal vein. Proximal ductal margin status after the right hepatectomy was compared between types. Results: Among 102 patients, 72 (70.5%) were R-UP type, and 30 (29.5%) were L-UP type. Rates of negative proximal ductal margin were higher with the L-UP type (27/30, 90.0%) than with the R-UP type (51/72, 70.8%; P = .04). On multivariate analysis, Bismuth-Corlette type II and IIIa (risk ratio 4.13, 95% confidence interval 1.52-11.5; P =.005) and L-UP type (risk ratio 4.03, 95% confidence interval 1.18-18.8; P = .04) were independent predictors of negative proximal ductal margin after a right hepatectomy for perihilar cholangiocarcinoma. Conclusion: For the course of the segment 4 hepatic artery, L-UP type rather than R-UP type might be anatomically advantageous for achieving negative proximal ductal margin in a right hepatectomy for perihilar cholangiocarcinoma. (c) 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).