Assessment and Prognosis in CSA-AKI Using Novel Kidney Injury Biomarkers: A Prospective Observational Study

SIMPLE SUMMARY: Cardiac surgery associated acute kidney injury is a common complication of cardiac surgeries that worsens postoperative outcomes and the patient’s prognosis. One of the main problems concerning this complication is its early diagnostics. In this study, the authors attempt to provide new data regarding the usage of novel kidney injury biomarkers in early detection of acute kidney injury and in the prognosis of the long-term postoperative kidney function. Perioperative factors that may influence kidney function were also analysed. It was concluded that biomarkers such as IL-6, IL-8, TNF-α, MMP-9 and NGAL are reliable acute kidney injury indicators. It was also demonstrated that intraoperative hypoperfusion secondary to hypovolemia is a main factor that damages the kidneys during cardiac surgeries. The authors hope that these findings will contribute to the development of new diagnostic protocols for acute kidney injury, which would involve novel renal biomarkers, thus enabling quicker diagnosis and more effective treatment of acute kidney injury. ABSTRACT: Background: There is a need for early diagnostic solutions for cardiac surgery associated acute kidney injury (CSA-AKI) as serum creatinine changes do not occur dynamically enough. Moreover, new approaches are needed for kidney protective strategy in patients undergoing cardiac surgery procedures; Methods: Samples of serum and urine were taken from the selected group of patients undergoing elective cardiac surgery procedures. The aim of this study was to assess the utility of specific inflammation and kidney injury biomarkers in the early diagnostic of CSA-AKI and in the prognosis of long-term postoperative kidney function; Results: At 6 h after weaning from cardiopulmonary bypass, there were significant differences in IL-6, IL-8, TNF-α, MMP-9 and NGAL concentrations in patients with CSA-AKI, compared to the control group. Serum IL-8 and urine NGAL 6 h after weaning from CPB proved to be independent acute kidney injury predictors. The TNF-α, MMP-9, IL-18, TIMP-1 and MMP-9/TIMP-1 ratio in the early postoperative period correlated with long-term kidney function impairment; Conclusions: Novel kidney injury biomarkers are an eligible tool for early diagnosis of CSA-AKI. They are also reliable indicators of long-term postoperative kidney function impairment risk after cardiac surgery procedures.