Anatomical complexity of the right-lobe grafts: influence on the outcomes in living donor liver transplantation

Background: The effect of graft anatomical complexity on post-transplant outcomes in living donor liver transplantation (LDLT) has not been fully elucidated. This retrospective study investigated the association between graft anatomical complexity and long-term graft survival in patients undergoing LDLT. Methods: Overall, 908 adult LDLT recipients of right-lobe grafts were categorized into complex (n=418) and control (n=490) groups based on graft anatomical complexities, such as multiple branches of the hepatic artery, portal vein, inferior hepatic vein (IHV), and bile duct (BD). Outcomes of both donors and recipients were compared, including matched analyses for each anatomical complexity. Results: Five-year graft survival rates were similar between the complex and control groups (83.1% vs . 77.9%, P=0.16), confirmed by propensity score matching (82.7% vs . 77.5%, P=0.27) and multivariate analysis [adjusted hazard ratio (aHR) 0.79, P=0.16]. Graft complexity was associated with an increased risk of BD complications (aHR 1.26, P=0.02). In the matched analyses for each anatomical complexity, grafts with two hepatic arteries showed comparable complication rates (7.7% vs . 3.4%, P=0.53) and higher BD complication rates than controls (79.5% vs . 43.4%, P=0.02). Interestingly, multiple IHV grafts were associated with better graft survival compared to those with one or fewer IHVs (93.4% vs . 75.4%, P=0.003), despite higher hepatic vein complication rates (8.2% vs . 3.5%, P=0.04). Major postoperative complications in living donors were similar in both groups (3.3%, P=0.99). Conclusions: Anatomical complexities of right-lobe grafts do not affect graft survival in LDLT, despite higher BD complications. Notably, multiple IHVs may be a positive factor for graft survival after LDLT.