Portal Flow Pulsatility as a Risk Factor for Acute Kidney Injury After Cardiac Surgery

Inclusion Criteria: * 18 years and older. * Undergoing cardiac surgery with the use of cardiopulmonary bypass * Able to provide consent. Exclusion Criteria: * Chronic renal replacement therapy before the procedure. * Chronic kidney disease stage 5 defined as a estimated glomerular filtration rate by the MDRD equation (eGFR-MDRD) of 15 mL/min/1,73m2 or less. * Critical pre-operative state defined as aborted sudden death, preoperative cardiac massage, preoperative ventilation before anaesthetic room, preoperative inotropes or intra-aortic counterpulsation balloon. * Patients previously diagnosed with a condition interfering with Doppler evaluation of the portal system: Portal vein thrombosis, Cirrhosis. * Patients with documented AKI before surgery. * Confirmed or suspected pregnancy. * Kidney transplant recipients.