The prospective single-center study investigates the association between changes in Doppler-derived renal venous flow and cardiac surgery-associated acute kidney injury (CSA-AKI).

CSA-AKI is a common postoperative complication in patients undergoing open heart surgery, and is associated with increased mortality and morbidity. Venous congestion has been identified as the principal cause of cardiorenal decompensation in patients with heart failure but the relative contribution of congestion-driven renal function decline in CSA-AKI is not well studied.

The prospective single-center study investigates whether serial Doppler-derived renal venous flow assessments could help identify subset of patients with cardiorenal syndrome and subclinical renal congestion at high risk of CSA-AKI.

Inclusion Criteria:

Inclusion criteria:

1. Subjects older than 18 years
2. Subjects undergoing elective cardiac surgery (with or without cardiopulmonary bypass)
3. Subjects who signed informed consent forms

Exclusion Criteria:

1. Patients requiring mechanical ventilation
2. Patients with mechanical circulatory assist devices or extracorporeal membrane oxygenation
3. Patients with stage 3 AKI with renal replacement therapy (RRT) or life- threatening volume overload treated with RRT
4. Stage ≥4 chronic kidney disease (CKD) stage
5. CKD requiring extracorporeal or peritoneal ultrafiltration for diuretic-resistant volume overload, 6) 6) Prediagnosed glomerulonephritis
6. Autosomal dominant polycystic kidney disease, postrenal obstruction, or solid organ transplantation
7. Anticipated life expectancy of <12 months
8. Likelihood of receiving advanced therapy (mechanical circulatory assist device/cardiac transplant)
9. Pregnancy or possibility of pregnancy in the next 3 months
10. Rhabdomyolysis

Patients undergoing cardiac surgery (with/without cardiopulmonary bypass) at Department of Cardiovascular Surgery, University Hospital Giessen and Marburg, Campus Giessen