Correlation between vasoactive-inotropic score and postoperative acute kidney injury after cardiovascular surgery

Abstract

Background: Acute kidney injury (AKI) is a common complication of cardiovascular surgery. The aim of this study was to investigate the correlation between Vasoactive-Inotropic Score (VIS) and postoperative acute kidney injury in adult patients with cardiovascular surgery. Methods: We retrospectively reviewed the data of 1935 adult patients who underwent cardiovascular surgery between September 2017 and May 2019. The data of patients included demographic data, laboratory findings, intraoperative details, and postoperative clinical outcomes. We calculated VIS-max by using the highest doses of vasoactive and inotropic medications during the first 24h after cardiovascular surgery. Logistic regression model was used to evaluate whether the VIS-max was independently associated with postoperative AKI. Additionally, improvements in risk reclassification and discrimination were evaluated by calculating the net reclassification improvement (NRI), C-index and the integrated discrimination improvement (IDI) with the addition of the VIS-max to a baseline model of the Society of Thoracic Surgeons (STS) score for analyzing the association of VIS-max with postoperative AKI. Results: In 1935 patients, 291 patients (15.0%) developed postoperative AKI from the second to seventh day after cardiovascular surgery, and 30 patients (1.6%) needed renal replacement therapy (RRT). In 291 patients with AKI, 3 patients (0.2%) with AKI class 1, 12 patients (0.6%) with AKI class 2, and 15 patients (0.8%) with AKI class 3 needed RRT. Multivariate logistic regression analysis showed that VIS-max was associated with postoperative AKI (odds ratio [OR]: 1.19, 95% confidence interval [CI]: 1.11-1.34, P < 0.001) and the need for RRT in AKI patients (OR: 1.29, 95%CI: 1.01-1.83, P = 0.007). The area under the ROC curves (AUROC) of VIS-max combining STS score for predicting postoperative AKI (AUROC: 0.84, 95%CI: 0.81-0.87, P < 0.001) and need of RRT (AUROC: 0.91, 95%CI: 0.86-0.96, P < 0.001) significantly were higher than the AUC of VIS-max, STS score and EuroSCORE. Inclusion of VIS-max into basic risk model of STS score provided an increase in all indexes of prognostic accuracy for postoperative AKI and need of RRT: C-statistic: 0.721, NRI: 21.8%, IDI: 4.9%; and C-statistic: 0.745, NRI: 24.7%, IDI: 5.6%, respectively. Conclusion: VIS-max is an independent predictor of postoperative AKI in adult patients after cardiovascular surgery and increases prognostic accuracy of STS score, allowing a risk reclassification.