Association Between Liver Graft to Recipient Weight Ratio and Acute Kidney Injury Following Liver Transplantation: A Historical Cohort Study

Introduction: Acute kidney injury (AKI) is a frequent complication following liver transplantation (LT) that has a multifactorial etiology. While some perioperative risk factors have been associated with postoperative AKI, the impact of liver graft weight to recipient body weight ratio (GW/RBW) has been poorly explored. We hypothesized that a high GW/RBW ratio would be associated with AKI after LT.

Methods: This single-center historical cohort study included all consecutive adults who had LT at Paul Brousse Hospital between 2018 and 2022. Patients requiring preoperative renal replacement therapy, combined solid organ transplantation, retransplantation, split or domino graft were excluded, as well as those with missing graft weight and creatinine values during the first postoperative week. The primary exposure was GW/RBW ratio expressed as a proportion. The primary outcome was the incidence of postoperative AKI within 7 days after surgery, defined using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The secondary outcome was the AKI severity (KDIGO grades). We estimated logistic and ordinal regression models adjusted for potential confounding factors and explored nonlinear associations.

Results: Of 467 patients analyzed, 211 (45%) developed AKI. A high GW/RBW ratio was associated with both the risk of postoperative AKI and the severity of AKI (KDIGO grades), especially above a threshold of 2.5% (non-linear effect).

Conclusion: A high GW/RBW ratio was associated with an exponential increase in the risk of AKI after LT. A high GW/RBW ratio was also associated with an increased AKI severity. Our findings may help improve graft allocation in patients undergoing LT.