New study aims to predict kidney damage after heart surgery using metabolic clues

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * All patients is going to undergo non-emergency cardiac surgeries, including cardiopulmonary bypass or non-cardiopulmonary bypass surgeries; * Patients must have the risk of developing AKI, and at least meet one of the following criteria: cardiopulmonary bypass cardiac surgery + at least one risk factor; or non-cardiopulmonary bypass surgery such as simple coronary artery bypass grafting + at least two AKI risk factors. The risk factors includes: * Age ≥ 70 years; * Diabetes (type 1 or type 2), requiring at least one oral hypoglycemic drug or insulin; * 30 ≤ eGFR ≤ 60 mL/min/1.73 m2 (CKD-EPI formula); * Recorded history of proteinuria (random urine albumin-to-creatinine ratio UACR \> 30 mg/g, or 24-hour urine albumin \> 300 mg/24 hours, or urine protein ≥ +1 in urine test strips/urine routine tests); * Previous history of hospitalization for congestive heart failure or NYHA classification III/IV; * Left ventricular ejection fraction (LVEF) ≤ 40%; ⑦ Previous history of open-chest cardiac surgery; * CABG combined with valve surgery; ⑨ Surgery involving more than one heart valve; ⑩ Emergency surgery; ⑪ Preoperative IABP Exclusion Criteria: * There were urgent indications for initiating RRT at the time of enrollment, including serum potassium ≥ 6.0 mmol/L, pH value ≤ 7.20, serum bicarbonate ≤ 12 mmol/L, oxygenation index ≤ 200 mmHg; presence of volume overload, severe respiratory failure, etc.; * Preoperative end-stage CKD (eGFR \< 30 mL/min/1.73 m2; or RRT treatment had been received within 4 weeks before enrollment); * AKI was present at screening. But transient (≤ 5 days) stage 1 AKI after iodinated contrast agent exposure will be included in this study. * Previous kidney transplantation or urinary tract obstruction and other urinary system diseases; * End-stage heart disease, HIV infection, hematological tumors, etc., * with an expected survival period of \< 1 year; * being in a moribund state (with an anticipated likelihood of death within 48 hours); * Multiple transfers to ICU; * Pregnant or lactating women; * Medical or psychological conditions that the investigator believed might interfere with the subject's participation in the study, or confuse the subject's assessment or study outcome.