The study aims to identify the Following: -

1. incidence and mortality of cardiac Surgery associated -AKI based on the new consensus diagnostic systems of KDIGO (Kidney Disease Improving Global Outcomes).
2. use of biomarkers for the early detection of clinical and subclinical cardiac Surgery associated-AKI.
3. risk factors and prediction models of cardiac Surgery associated-AKI.
4. optimal cardiac surgical procedures including conventional versus minimally invasive approaches, on-pump versus off-pump, and optimal management of cardiac surgical support including duration of CPB, perfusion pressure, hemodilution, and hypothermia during CPB.
5. controversial pharmacologic therapies for the prevention and treatment of cardiac Surgery associated-AKI including statins, sodium bicarbonate, and N-acetylcysteine (NAC).

Acute renal injury (AKI) is a severe complication that occurs in 3.5-31.0% of patients undergoing cardiac surgery, making it one of the most common complications observed in this group of patients.

Evidence suggests that even slight postoperative increases in serum creatinine levels are associated with a significant increase in the risk of death. Among individuals undergoing cardiac surgery, mortality has been reported to be as high as 8% and postoperative AKI can increase the mortality rate to over 60%. The occurrence of AKI in patients undergoing cardiac surgery raises the mortality rate from 0.4-4.4% to 1.3-22.3%; when those same patients require dialysis, rates range from 25% to 88.9%, making severe postoperative AKI an independent risk factor for mortality that results in an 8-fold increase in the risk of death. Therefore, cardiac surgery AKI is associated with serious complications as well as with prolonged intensive care unit (ICU) stays and with a worse quality of life. It also increases early and late mortality and health care expenditures.

The early identification of patients at risk of developing AKI after cardiac surgery is an important strategy for improving the care of such patients during the intraoperative and postoperative periods. Many factors have been found to facilitate the development of AKI after cardiac surgery such as: age; obesity; female gender; valve replacement surgery; myocardial infarction in the last 30 days; low cardiac output; blood transfusion; and many others.

Epidemiological studies of AKI in cardiac surgery patients are important because they allow for better diagnosis of AKI and facilitate the prognosis estimation, as well as the development of new, more effective strategies to prevent and minimize this complication, thus reducing the associated morbidity and mortality.

Inclusion Criteria:

• On-pump cardiac surgery;
• Off-pump Cardiac Surgery;
• Informed and written consent of the patient or inclusion according to the emergency procedure;
• Affiliated patient or beneficiary of a social protection.

Exclusion Criteria:

• Patients who underwent cardiac surgery for congenital heart disease.
• Patients who underwent emergency heart surgery.
• patients who, within the last 72 hours before surgery, were injected with iodinated contrast (because of its potential nephrotoxicity).
• patients with chronic Kidney disease. 5- patients with a preoperative serum creatinine >2 mg/dL.
• patients who died within the first 24 hours after surgery.
• patients on mechanical ventilation before intervention.
• Patients with preoperative medical disorders other than cardiac affection.

All patients between 18 and 80 years of age who will undergo cardiac surgery, between 2021 and 2024, except those mentioned in exclusion criteria. All the procedures will be performed at a tertiary care cardiac hospital that serves the public and private sector.