Perioperative neurological complications in cardiovascular surgical procedures are associated with a significant risk of mortality and disability. The goal of this clinical trial is to learn if ischemic preconditioning and transcranial electrical stimulation to reduce perioperative neurological complications. It will also learn about the safety of remote ischemic preconditioning and transcranial electrical stimulation before cardiac surgery. The main questions it aims to answer are "Do remote ischemic preconditioning and transcranial electrical stimulation make good effect on perioperative neurological complications?" "Are remote ischemic preconditioning and transcranial electrical stimulation safe?" Researchers will compare remote ischemic preconditioning and transcranial electrical stimulation to traditional treatment to see if remote ischemic preconditioning and transcranial electrical stimulation work to reduce perioperative neurological complications.

Participants will:Undergo remote ischemic preconditioning and transcranial electrical stimulation or sham treatment twice every day for 3 days before surgery.

Undertake psychological assessment and clinical symptom follow-up after cardiac surgery.

Inclusion Criteria:

1. Age range: 18-80 years old;
2. Surgical patients with heart disease;
3. Elective surgery;
4. Patients identified as high-risk for postoperative neurological complications; Previous stroke history; Moderate to severe stenosis of the head and neck arteries was evaluated;
5. Be able to understand and comply with the requirements of clinical trial protocols, and voluntarily sign informed consent forms.

Exclusion Criteria:

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