Acute Kidney Injury After Cardiac Surgery

Inclusion Criteria:

1. Subjects older than 18 years
2. Subjects undergoing elective cardiac surgery (with or without cardiopulmonary bypass)
3. Subjects with an estimated GFR ≥60 ml/min/1.73 m2 (CKD-Epidemiology Collaborationequation)
4. Subjects who signed informed consent forms

Exclusion Criteria:

1. Preexisting acute kidney injury (as determined by all available serum creatininevalues from hospital and outpatient medical records within the previous 90 days)
2. Chronic kidney disease ≥ stage III (KDIGO)
3. Subjects undergoing transcatheter aortic valve implantation (TAVI)
4. Pregnancy
5. Solitary kidney
6. Diabetes mellitus type 1
7. Recent cardiac arrest (within last 3 months)
8. Liver failure or cirrhosis
9. Total parenteral nutrition
10. Hemoglobin <11 g/dl
11. Sepsis
12. History of malabsorption, chronic inflammatory bowel disease, short bowel, orpancreatic insufficiency
13. Transplant donor or recipient
14. Active autoimmune disease with renal involvement
15. Rhabdomyolysis
16. Prostate hypertrophy with International Prostate Symptom Score ≥20
17. Active neoplasm
18. Decompensated heart failure / inability to pause angiotensin-converting enzymeinhibitors or angiotensin II receptor blockers minimum 2 days before protein load
19. Known iodine allergy (exclusion criteria only for those centres who use iohexol plasmaclearance for determination of GFR)
20. TSH <0.3 µU/l (exclusion criteria only for those centres who use iohexol)
21. Subjects who received intravenous radiocontrast agents within the 72 hours before theprotein load
22. Subjects who received NSAIDs within 48 hours before the protein load