Inclusion Criteria:  Patients aged ≥18 years； Patients undergoing elective isolated coronary artery bypass surgery (with or without bypass)； In line with ethics, the patients volunteered to take the test and signed the informed consent for the clinical study;  Exclusion Criteria:  Patients with severe renal insufficiency before surgery; Preoperative patients with moderate or more than moderate valvular lesions required surgery; Diabetic patients with a history of serious diabetic complications (diabetic ketoacidosis, hyperosmolar coma, various infections, macrovascular lesions, diabetic nephropathy)； Patients with TEE contraindications