The aim of the study is to identify the correlation between ischaemia reperfusion injury and postoperative multiorgan damage during cardiopulmonary cardiac surgery; and to investigate biomarkers that can predict postoperative organ damage in cardiac surgery.

This study proposes to observe multi-organ functional impairment of the heart, kidney and brain after extracorporeal circulation in a prospective study of clinical patients; to obtain markers with diagnostic and predictive efficacy by collecting pre and postoperative serum and heart and ear tissue samples from patients with postoperative organ functional impairment, performing combined proteomic and metabolomic analyses, and by analysing them with detailed postoperative clinical prognostic data using machine learning algorithms.

Inclusion Criteria:

1. Age ≥50 years; patients requiring mitral valve replacement surgery or mitral valve plus aortic valve replacement under cardiopulmonary bypass
2. Agreed to participate in this study, and signed the informed consent form.

Exclusion Criteria:

1. History of neurological disease (stroke, reversible ischemic hypoxia, transient ischemic attack, or Neurodegeneration) ;
2. Patients with severe preoperative renal insufficiency (serum creatinine > 442 μmol/L or need renal replacement therapy) ,
3. liver dysfunction (Child-Pugh grade C)
4. myocardial infarction within 4 weeks
5. ASA grade ≥ V

Patients were screened from the outpatient clinics of the Second Hospital of the Army Medical University who were proposed for mitral valve replacement or mitral valve combined with aortic valve replacement, agreed to participate in this study, and signed an informed consent form.

The individual participant data for this study is available from the sponsor on reasonable request through email.

Within five years