Relevance of Slpi as Biomarker of Acute Kidney Injury After Open and Endovascular Complex Aortic Surgery

Abstract

Introduction: Open and endovascular repair of thoracoabdominal aortic aneurysm (TAAA) is related to a relevant rate of postoperative complications such as acute kidney injury (AKI), which is in turn closely linked with poor patients` outcome. Hence an early detection of AKI may enable an immediate start of specific treatment bundles. In this context, the necessity of clinically available early and reliable biomarkers for AKI becomes evident. Secretory leukocyte proteinase inhibitor (SLPI) is a protease inhibitor and regulator of innate and adaptive immunity. It is synthesized predominantly in immune cells and epithelial cells of mucosal surfaces, such as the pancreas and kidney. Patients with AKI showed significantly increased SLPI plasma and urine levels when compared with patients without AKI. The aim of this study was to evaluate SLPI as a potential predictive biomarker of postoperative AKI in patients undergoing complex open and endovascular aortic aneurysm repair. Methods: Between January and December 2017 33 patients have been enrolled in this prospective, non-randomized single-center study. Serum samples were collected at six defined time points until 72 hours after surgery. AKI was defined according to the KDIGO criteria. In a subgroup analysis, patients with preexisting kidney disease (defined as preoperative serum creatinine > 1.2 mg/dl according to the Cleveland clinic foundation score) were excluded. Results: The mean patients' age was 66 ± 16 years. A total of 13 patients (53.3 %) developed postoperative AKI. Serum SLPI showed an early and significant increase within the first 12 hours after surgery until 72 hours after surgery. Patients suffering from AKI showed significantly higher serum SLPI 12 hours after surgery when compared to patients without AKI (p=0.008). The ROC analysis revealed a prognostic accuracy with an Area under Curve [AUC]=0.783 for SLPI as a biomarker of AKI 12 hours after surgery (p=0.009). After exclusion of patients with underlying kidney disease, 20 patients were further analyzed from which 11 patients (55%) showed postoperative AKI. In this group, an even stronger correlation between serum SLPI and AKI was evident: Significantly increased serum SLPI 12, 24, and 48 h after surgery could be observed (12 h: p=0.0002, 24 h: p=0.0016, 48 h: p=0.025). Besides, the respective ROC analysis showed an AUC=0.949 for 12 hours after surgery (p=0.0001), AUC=0.899 for 24 hours after surgery (p=0.0003), and AUC=0.795 for 48h after surgery (p=0.025). Conclusion: The present findings highlight SLPI as a reliable and promising marker for the early detection of postoperative AKI after open and endovascular TAAA repair, Besides, these results potentially suggest a general applicability of SLPI as a biomarker of AKI. Disclosure: Nothing to disclose