The Authors' Reply: Anatomical and Extra-Anatomical Hepatic Artery Reconstruction During Living Donor Liver Transplantation: Is It Reasonable to Classify This Way? (2020)

Our study included 800 living donor liver transplantations, 35 (4.4%) of which underwent extra-anatomical reconstruction (EAR).1 As indicated by this small number of cases, EAR is not a preferred method. During living donor liver transplantation, the best option is using branches of the hepatic artery, which enables the easiest and safest reconstruction with regard to length, width, and course of the inflow. Nevertheless, there are situations in which AR is not feasible, and EAR is 1 alternative. The purpose of this study was to analyze the impact of EAR. By carefully reviewing our data and adjusting for confounding factors, we showed that performing EAR when AR is not feasible does not add risk for the recipient. Instead, our data demonstrated that hepatic artery complications are the main risk, and if the surgeon can avoid hepatic artery complications, EAR is safe and feasible for the recipient. In fact, there were no differences in hepatic artery complications after EAR compared with AR (P = 0.699). However, more patients experienced hepatic artery complications in the EAR group (P < 0.001) since 7 patients who experienced complications after AR were included in the EAR group. Multivariable analysis showed that biliary stricture-free (P = 0.059), graft (P = 0.203), and overall survival (P = 0.251) were similar, while the occurrence of hepatic artery complications was associated with biliary stricture-free (P = 0.001), graft (P < 0.001), and overall survival (P = 0.008). Regarding the perfusion of the end arterioles of the bile duct on both the graft and recipient side, the key is not to compromise inflow to the pericholedochal arteries. Performing AR using the right, middle, or left hepatic artery will not provide additional benefit for the bile duct opening on the graft side if EAR can supply a similar amount of blood, since inflow into the end-arterioles is influenced by inflow through the arterial anastomosis. On the other hand, perfusion on the recipient side is supplied by branches from hepatic arteries. Therefore, minimal manipulation of the hilar structure preserves perfusion of the bile duct on the recipient side (Figure 1).FIGURE 1.: Vascular supply of the bile duct during living donor liver transplantation using a right graft. A, Schematic illustration of arterial inflow of the bile duct. B, Arterial inflows of the end bile ducts on the graft and recipient. End perfusion is influenced by arterial inflow through the anastomosis on the graft side and from the small branches from the hepatic arteries on the recipient side. C, End-arterial inflow to the bile duct anastomosis after biliary reconstruction. However, only the bile ducts are anastomosed while end arterial inflows do not communicate with each other. LHA, left hepatic artery; MHA, middle hepatic artery; RHA, right hepatic artery.The classification of AR and EAR was adopted from a study by Uchiyama et al2 that classified AR and EAR based on the original destination of the arterial branches, as is the preference of our surgical team. Although surgeon preference may vary, using the classification proposed by Uchiyama et al seems reasonable. Regarding the preservation solution, we only used histidine-tryptophan-ketoglutarate solution. AR is better than EAR due to its simplicity. However, when AR is impossible due to poor structural quality and short length, EAR is a good alternative.