Factors Determining Postoperative Acute Kidney Injury Following Cardiac Surgery

Abstract

Purpose: Acute kidney injury is a recognised complication following cardiac surgery. Though the aetiologies, and risk factors are widespread, it can be associated with increased morbidity, mortality, and length of stay. Methodology: A retrospective review of prospectively collected data from Royal Perth Hospital and Fiona Stanley Hospital in Perth, Western Australia, over the previous five years identified all patients who sustained an acute kidney injury following cardiac surgery. Patients with preoperative dialysis or working kidney transplant were excluded. Results: Of 1,554 patients identified, 205 (13.2%) suffered an acute kidney injury. They tended to be older (64.21 ± 0.98 vs 60.37 ± 0.41 years, p = 0.0005), more likely to be diabetic (17.1% vs 11.4%, p = 0.002), and more likely receiving surgery for endocarditis (27.2% vs 13.7%, p = 0.002). Blood transfusion was also associated with a higher incidence (61.2% vs 38.1%, p < 0.001). There was no difference in the incidence of renal failure in Indigenous patients (10.98% vs 13.45%, p = 0.46), nor male gender (71.2% vs 71.7%, p = 0.89). Preoperative creatinine was also surprisingly not associated (115.8 ± 4.22 vs 106.4 ± 3.08, p = 0.25). There was significantly higher 30-day mortality in the cohort with acute kidney injury (12.2% vs 1.48%, p < 0.001). Conclusion: We have identified several preoperative characteristics for the development of acute kidney injury following cardiac surgery. We also discuss intraoperative factors, including fluid management, and drug administration.