Efficacy and Safety of ENN0403 in Patients At High Risk for Acute Kidney Injury Following Elective Cardiac Surgery

Inclusion Criteria: 1. Ability to understand and comply with the study requirements and able to provide written informed consent; 2. Age ≥18 and ≤85 years; 3. Male subjects (and their fertile female spouses/partners) do not have pregnancy plans during the screening period and within 3 months after the last dose, voluntarily take highly effective contraception, and must not donate sperm or ova. Only non-fertile women will be enrolled, and female subjects who meet the following criteria are not considered fertile: Postmenopausal status has been achieved, normal menstruation has stopped for at least 12 consecutive months with an FSH \>30 IU/L in the absence of other pathophysiological causes, or there is a medical record showing hysterectomy \\ bilateral tubal resection and/or bilateral ovariectomy. 4. Subjects must be scheduled for cardiac surgery requring cardiopulmonary bypass: Coronary artery bypass grafting (CABG) and/or heart valve surgery and/or aortic root, ascending aorta and aortic arch surgery; 5. Subjects have the risk of developing AKI with at least one of the following criteria: coronary artery bypass grafting combined with one or more heart valves surgery plus at least one risk factor for AKI; Multiple heart valves surgery plus at least one AKI risk factor; Coronary artery bypass grafting or aortic valve surgery combined with aortic root, ascending aorta, and aortic arch surgery (non-aortic dissection) plus at least one risk factor for AKI; Coronary artery bypass grafting alone or single heart valve surgery plus at least 2 risk factors for AKI. Exclusion Criteria: 1. Receive ICD or permanent pacemaker implantation, mechanical ventilation, IABP, LVAD or other mechanical circulatory AIDS within 1 week before surgery; 2. Cardiopulmonary resuscitation is performed within 14 days prior to screening; 3. Abnormal renal function with eGFR\<20 mL/min/1.73 m2 within 30 days before screening; 4. Receive renal replacement therapy or the presence of AKI within 30 days before surgery, except for transient (≤5 days) stage 1 AKI after iodized contrast agent exposure; 5. Participate in other clinical trials within the past 1 month; 6. Have a known allergy to investigational drug or any of its constituents, or allery to any constituents used during the study; 7. Subjects with intractable hypotension, severe hypoxemia or other emergency during surgery.