Low Preoperative Antithrombin III level is Associated with Postoperative Acute Kidney Injury after Liver Transplantation

Background: The reno-protective effect of Antithrombin III (ATIII) has been well-studied in various animal studies; however, little is known about the effect of ATIII on kidney function in patients undergoing liver transplantation (LT). This study aimed to determine the association between preoperative ATIII level and postoperative acute kidney injury (AKI) after LT (post-LT AKI).Methods: We retrospectively evaluated 2,395 LT recipients between 2010 and 2018 whose data of perioperative ATIII levels were available. Patients were divided into two groups based on the preoperative level of ATIII (ATIII<50% vs. ATIII≥50%). Multivariable regression analysis was performed to assess the risk factors for post-LT AKI. In addition, subgroup analysis for the Model for End-stage liver disease (MELD) score (<20, ≥20) and donor types (deceased vs. living) were performed to identify the predictive value of ATIII.Results: The mean preoperative ATIII levels were 30.2±11.8% in the ATIII<50% group and 67.2±13.2% in the ATIII≥50% group. The incidence of post-LT AKI was significantly lower in ATIII≥50% group compared to that in the ATIII<50% group (54.7% vs. 75.5%, P<0.001; odds ratio [OR, per 10% increase of ATIII level] 0.86, 95% confidence interval [CI] 0.81–0.92; P<0.001). The prognostic value of ATIII was found to be statistically significant in the low-MELD group (<20, OR 0.82, 95% CI 0.77–0.87, P<0.001) and living donor LT (OR 0.89, CI 0.85–0.94, P<0.001) group. After a backward stepwise regression model, female sex, high body mass index, low albumin, deceased donor LT, longer duration of surgery, and high red blood cell transfusion remained significantly associated with post-LT AKI.Conclusion: Low preoperative ATIII level is associated with post-LT AKI, suggesting that preoperative ATIII might be a prognostic factor for predicting post-LT AKI.