Predictive utility of postoperative serum myoglobin in acute kidney injury after liver transplantation

BACKGROUND Acute kidney injury (AKI) is a common and multifactorial complication after liver transplantation (LT). Myoglobin (Mb) which can be served as O2 storage and delivery depot is present in muscles and cardiac myocytes. Previous studies had shown the close relationship between Mb and AKI. But there is a lack of clinical studies for Mb with the risk of AKI due to LT. This study was performed to determine the association between the serum level of Mb and incidence of AKI in patients underwent LT. METHODS The clinical data of 140 consecutive adult patients who underwent LT at our center from June 2018 to August 2020 were analyzed in this study. One hundred and fifteen patients met the inclusion criteria. The performances of postoperative laboratory variables (including serum Mb) were evaluated. The outcomes after LT, including the duration of intensive care unit (ICU) stay, hospital stay and 28-day mortality, were also measured. RESULTS We divided 115 patients into AKI group (n=44) and non-AKI group (n=71). Serum Mb on postoperative day 0 (POD0) was significantly higher in AKI group than those in non-AKI group (P<0.001). According to univariate and multivariable logistic regression analysis, the levels of serum albumin (P=0.024), alanine transaminase (P=0.007) and Mb (P=0.006) on POD0 were independently associated with development of new AKI. The area under curve (AUC) of serum Mb after LT immediately had the best value for predicting AKI [AUC: 0.755, sensitivity: 63.6%, specificity: 77.3%, 95% confidence interval (CI): 0.661-0.849], its cut-off value was 957 ng/mL. CONCLUSIONS Postoperative serum Mb was an independent risk factor for new AKI and could increase the accuracy of predicting the occurrence of post-LT AKI. TRIAL REGISTRATION The study was registered in Chinese Clinical Trial Registry (registration number: ChiCTR2100044257).