Safety & Efficacy of RenalGuard® Therapy in the Prevention of Cardiac Surgery Associated Acute Kidney Injury

Inclusion Criteria: 1. Male or female and \>18 years old. 2. Patient able to give written consent. 3. Scheduled for the following non-emergent cardiac surgery procedure requiring CPB, isolated or in combination: * coronary artery bypass graft (CABG) * aortic valve replacement or repair alone, with or without aortic root repair * mitral, tricuspid, or pulmonic valve replacement or repair * simultaneous replacement of several cardiac valves * CABG with aortic, mitral, tricuspid, or pulmonic valve replacement or repair * Surgery on the aorta: aortic root and/ or ascending aorta * AF ablation surgery if combined with other cardiac procedures. * ASD closure if combined with other cardiac procedures. * Excision of myxoma if combined with other cardiac procedures 4. Have at least one of the following risk factors for CSA-AKI: * CKD-EPI eGFR 20-59 mL/min/1.73 m² * Undergoing combined surgery (e.g. CABG + Valve) * STS Score ≥4 or Logistic EuroScore of ≥5 or, Euroscore II of ≥4 * Left ventricular ejection fraction (LVEF) ≤ 35% * Insulin-requiring diabetes * Non-insulin-requiring diabetes with HbA1C ≥ 6.1% in the last 6 months * Preoperative anemia (hemoglobin ≤11g/dl for men and women) within 4 weeks of surgery Exclusion Criteria: 1. Patient requiring emergency surgery 2. Surgery to be performed without CPB 3. Patient receiving furosemide at a dose\>100 mg/day orally (or the equivalent dose of an alternative loop diuretic) in the last week 4. Patient who cannot be urethrally catheterize for any reason 5. Patients already dialysis dependent 6. Patients with CKD-EPI eGFR \<20 mL/min/1.73 m² 7. Known or suspected AKI (KDIGO criteria) at the time of screening 8. IV contrast within 48 hours of surgery 9. Patients participating in another interventional drug or device study or have received an investigational drug or device treatment within the last 30 days 10. Pregnant patient, self-reported 11. Patients whose planned surgery to be performed under conditions of circulatory arrest or hypothermia with rectal temperature \< 28°Celsius (82.4° Fahrenheit) 12. Patient with suspected or confirmed bacteraemia, endocarditis, or pyelonephritis at hospital admission 13. Patients with pneumonia, aspiration, or bilateral pulmonary infiltrates from an infectious aetiology reported on chest x-ray or CT scan in the last 7 days 14. Patients in cardiogenic shock or hemodynamic instability which require inotropes or vasopressors or other mechanical devices (Impella, IABP) within 24 hours prior to surgery 15. Patients on extracorporeal membrane oxygenation (ECMO) or durable ventricular assist device (VAD) at the time of screening, or planned use within 24h prior to surgery 16. Patients currently treated with chemotherapy or radiation therapy that may have an impact on kidney function. 17. Patient underwent prior solid organ transplantation 18. Patients underwent major surgery within the last 3 months 19. Any condition which, in the judgement of the investigator, might increase the risk to the patient