Cardiac surgery-related acute kidney injury - risk factors, clinical course, management suggestions

OBJECTIVE: Acute kidney injury (AKI) is a common complication after cardiac surgery (CS). Since a therapeutic regime remains scarce, an early implementation of preventive strategies is crucial. We investigated risk factors and the typical clinical course of CS-associated AKI (CS-AKI) to derive strategies for perioperative clinical routine. DESIGN: Retrospective data analysis. SETTING: The data were collected from clinical routine in a maximum care university hospital. PARTICIPANTS: Patients. INTERVENTIONS: We retrospectively analyzed data from 538 patients who underwent CS. MEASUREMENTS AND MAIN RESULTS: The median age of the 466 patients included was 66.6 years; 65.7% were male. AKI occurred in 131 (28.1%) patients, mainly (89.0%) starting within 72 hours postoperatively. 31 (6.7%) patients showed KDIGO AKI stage 3. AKI was significantly more frequent in patients with chronic kidney disease (p<0.001), emergency admission (p<0.001), heart failure (p<0.001) and if postoperative complications occurred (p<0.001). In a multivariable analysis, postoperative CS-AKI risk significantly decreases with each 1 or 10 ml/min preoperative glomerular filtration rate (GFR) (OR 0.962 and 0.677;95% CI 0.947-0.977 and 0.577-0.793;p<0.001 and p<0.0001). Only in patients who developed KDIGO AKI stage 3, a trend to decreased GFR and increased creatinine levels was observed early postoperatively. CONCLUSIONS: Especially in patients with preexisting CKD and signs of CS-AKI occurring on the day of surgery, close monitoring of renal function should be performed for at least 72 hours after CS to detect an onset of AKI early and initiate renal protective strategies. An optimal preoperative fluid management might prevent postoperative AKI