Application Of CTnI And NT-proBNP In Predicting Postoperative Acute Kidney Injury In Non-cardiac Surgery A Single-centered Retrospective Cohort Study

Background and objective:Acute kidney injury(AKI)is a clinical syndrome characterized by rapid loss of renal excretion function,resulting in metabolic waste accumulation or urine output reduction,or both.AKI is one of the most common postoperative complications in surgical patients,which has an important impact on their prognosis.Studies have shown that postoperative AKI is associated with a variety of risk factors.In cardiac surgery,a number of preoperative risk predictive models for postoperative AKI have been established by using AKI-related predictors,but there are few preoperative risk predictive models for postoperative AKI in non-cardiac surgery.Cardiac troponin I(cTnI)and amino-terminal brain natriuretic peptide precursor(NT-proBNP)have been revealed to have outstanding performance in the prediction of cardiovascular disease and postoperative cardiovascular complications in surgeries.However,it remains unclear whether these two indices are of value in the prediction of postoperative AKI in non-cardiac surgery.Therefore,we intend to explore the predictive value of cTnI and NT-proBNP in postoperative AKI in non-cardiac surgery through a single-center retrospective cohort study.Methods:The predictors involved in the risk prediction model of postoperative AKI in patients undergoing major non-cardiac surgery were selected in previous studies abroad.Data platform of Department of Anesthesiology,Nanfang Hospital of Southern Medical University was used to collect relevant data of patients undergoing major non-cardiac surgery.Specifically,only those who had preoperative cTnI and NT-proBNP test were included in our study.Multiple logistic regression analysis was used to construct risk predictive model of postoperative AKI in this cohort.Then cTnI and NT-proBNP were included as independent variables in the above model,and the predictive ability of these two models were compared.Results:A total of 2968 patients were enrolled in the study.In this cohort,the incidence of postoperative AKI was 10.3%(306/2968).The area under the receiver operating characteristic curve(AUROC)of the risk predictive model established with 11 selected predictors was 0.746,among which male,chronic kidney disease,hypertension,ASA grade,intraabdominal surgery and emergent surgery were still independent risk factors of postoperative AKI.After addition of cTnI and NT-proBNP,the AUROC of the model increased by 0.009,with a net reclassification index(NRI)of 5.25%(p<0.05),and an integrated discrimination improvement(IDI)of 0.73%(p<0.05).These results revealed that cTnI and NT-proBNP can improve the predictive ability of the original model for postoperative AKI in non-cardiac surgery.Conclusion:In major non-cardiac surgery,the incidence of postoperative AKI is 10.3%.The application of cTnI and NT-proBNP can improve the predictive ability of preoperative risk prediction model for postoperative AKI in patients undergoing major non-cardiac surgery.