Early bifurcation of hepatic artery in right-sided living-donor hepatectomy at Asan Medical Center: rarely a critical issue

In living donor liver transplantation (LDLT), early bifurcation of hepatic artery (HA) relative to the cutting line of bile duct (BD) requires additional skeletonization of the hilar plate, especially around BD, compared to opposite condition. Subsequently, it may preclude higher chances of biliary complications such as bile leak and biliary stenosis in the donor. Hence, donor surgeons should be well aware of the anatomical correlations among HA, BD, and portal vein (PV), based on preoperative 3-dimensional (3D) images, and also intraoperatively perform meticulous dissection of HA from the surrounding tissues and minimize the damage of microcirculation to the BD without using energy devices such as electrocautery (1). When extensive dissection around BD & its ischemic damage in the donor is expected to obtain single HA opening of the harvesting graft, we prefer separate two HA openings including right anterior and posterior HAs to single right HA (RHA) opening without skeletonization of donor’s BD.

Kusakabe et al. conducted a retrospective analysis about the association of early bifurcation of HA with artery injury in 500 right-sided living-donor hepatectomy cases using preoperative All-in-one 3D images (2). The authors described informative anatomical results about the proportion of early bifurcation of the RHA and also the right posterior HA (RPHA) according to its infra- or supra-portal position. The overall incidence of early bifurcation was 19.9% for RHA and 43.6% for RPHA. For right posterior sector graft (RPSG) procurement, particular care should be taken for early bifurcation or separate branching of artery to segment 6 (A6) and 7 (A7). All-in-one 3D imaging is superior to conventional 3D imaging in regard to detection of those anatomical variations.

At Asan Medical Center (AMC), preoperatively we have not performed All-in-one 3D imaging but performed both conventional 3D imaging and magnetic resonance (MR) cholangiography for donor hepatectomy. Until now, there has been no accidental arterial injury related to the insufficient anatomical information obtained from both conventional 3D imaging and MR cholangiography. As a result, we might infer all-in-one 3D imaging can be a useful tool to delineate hilar anatomies and be helpful in making a preoperative plan, but it is recommended to avoid arterial injury because donor surgeons already have many experiences not only as an assistant to donor hepatectomy but also as an operator of hepatic resection, obtaining adequate anatomical information preoperatively from the conventional imaging studies alone, and subsequently careful and meticulous hilar dissection to identify RHA or RPHA is much more important to avoid arterial injury.

Considering around 20% incidence of early bifurcation RHA reported by Kusakabe et al. (2) there might be a high chance of biliary ischemic damage from skeletonization of hilar plate to obtain single RHA opening in right lobe graft (RLG) procurement. However, biliary ischemic damages in the donor have rarely occurred at AMC, and it can be explained by two critical reasons. First, we perform meticulous hilar dissection maximally preserving peri-ductal connective disuse and maintaining micro-vascular supplies to BD. Second, when skeletonization of hilar plate is inevitable to obtain single RHA opening and ischemic biliary damage is expected, we would rather dissect right anterior & posterior HAs at the peripheral side of RHA without denuding of peri-ductal connective tissues. From our study by Kim et al. (3), among 1,601 right lobe LDLTs, two HA openings came out in 83 RLGs (83/1,601, 5.2%), and 45 RLGs (45/1,601, 2.8%) had two HA openings due to early bifurcation of RHA. Other two HA openings of 32 RLGs were related to accessory RHA from the superior mesenteric artery (19 RLGs) and gastroduodenal artery (18 RLGs). Both HAs of 77 RLG (77/83, 92.8%) were all reconstructed except 6 RLG undergone one HA reconstruction to the larger HA due to mainly absence of adequate inflow or some technical difficulty. HA thrombosis occurred in 1.2% (20/1,601) who underwent surgical revascularization, but there was 0% HA thrombosis in 77 RLG undergone both HA reconstruction. According to Kusakabe et al. (2), they had only two cases of HA injuries but all the other RLGs seemed to have single RHA opening. If it was correct presumption, there would be higher chances of ischemic biliary damage in the donors considering AMC experiences that 2.8% of RLGs had two HA openings related to early bifurcation of RHA to avoid harmful ischemic damages in the donors’ BD.

Kusakabe et al. (2) described around 44% of RPHA had early bifurcation, and in Fig. 3, the authors exclude PV type 3 patients (22 patients), and experienced accidental A6 injury in 1 case among 5 RPSG procurement. We must emphasize why authors perform RPSG in the donors having unfavorable anatomical conditions such as A6 injury case with type 1 PV. At our institution, Hwang et al. (4) reported about feasible condition and anatomy of RPSG as follows. Exact assessment of the RPSG volume and PV anatomy should be taken into consideration simultaneously for successful procurement of RPSG. When the left volume is disproportionately small (<30% of whole liver volume), the presence of type 3 PV will make the possibility of RPSG procurement acceptably high due to surgical feasibility of extrahepatic encircling of RPHA and right posterior PV. However, nearly all of the liver with type 1 PV and many of livers with type 2 PV may not be suitable for RPSG procurement because their associated anatomy will not permit uneventful isolation of the RPSG. As a result, 26 LDLTs were performed using RPSG between January 2004 and June 2018, and all the RPSG had single-orifice BD and RPHA without accidental arterial injury due to the anatomical feasibility, and subsequently reduced biliary complications (5).

As surgeons who perform hepatectomy for diseased patients or living donors, we should obtain detailed anatomical information about vascular and biliary tract based on preoperative imaging and prevent critical injuries during operation. Kusakabe et al. report gives us useful anatomical knowledges using All-in-one 3D images and can be helpful to perform preoperative surgical imaging training. However, their surgical approaches at the time of donor hepatectomy might be a risk factor to the donor in some aspects compared to our former mentioned practice. In addition, association of early bifurcation of HA with arterial injury is rarely a critical issue in right-sided living-donor hepatectomy at AMC.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Hepatobiliary Surgery and Nutrition. The article did not undergo external peer review.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://hbsn.amegroups.com/article/view/10.21037/hbsn-24-75/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Lee SG. A complete treatment of adult living donor liver transplantation: a review of surgical technique and current challenges to expand indication of patients. Am J Transplant 2015;15:17-38. [Crossref] [PubMed]
2. Kusakabe J, Taura K, Sasaki K, et al. Association of Early Bifurcation of Hepatic Artery With Arterial Injury in Right-Sided Living-Donor Hepatectomy: Retrospective Analysis of 500 Cases. Ann Surg 2023;277:e353-8. [Crossref] [PubMed]
3. Kim SM, Moon DB, Ahn CS, et al. Reconstruction of all hepatic arteries in right lobe grafts with 2 hepatic arteries and zero percent hepatic artery thrombosis. Liver Transpl 2024;30:628-39. [Crossref] [PubMed]
4. Hwang S, Lee SG, Lee YJ, et al. Donor selection for procurement of right posterior segment graft in living donor liver transplantation. Liver Transpl 2004;10:1150-5. [Crossref] [PubMed]
5. Na BG, Park GC, Hwang S, et al. Biliary Complications After Single- and Dual-Graft Living-Donor Liver Transplantation Using a Right Posterior Section Graft of Donor with a Type III Portal Vein Variation. Transplant Proc 2020;52:1838-43. [Crossref] [PubMed]