Remote Ischemic Preconditioning for Aute Type A Aortic Dissection Surgery

Inclusion Criteria: 1. Age ≥18 years; 2. Acute type A aortic dissection requiring emergency surgery within 14 days of symptom onset; 3. Written informed consent provided by the participant or a legally authorized representative; 4. Willingness to comply with study follow-up. Exclusion Criteria: 1. Traumatic or iatrogenic aortic dissection; 2. Previous open cardiac or thoracic aortic surgery; 3. Persistent deep coma (Glasgow Coma Scale score ≤8), abdominal compartment syndrome, preoperative mechanical circulatory support, or norepinephrine-equivalent dose \>0.1 μg/kg/min; 4. Estimated glomerular filtration rate \<30 mL/min/1.73 m², total bilirubin \>342 μmol/L, or international normalized ratio \>2.0; 5. Evidence of ischemia in the limb planned for intervention, including decreased skin temperature, pain, or pallor, with or without sensory disturbance, paralysis, or diminished or absent peripheral pulses; severe deformity of the limb; or a history of arterial or venous surgery at the planned intervention site; 6. Peripheral arterial disease involving the limbs, Raynaud phenomenon, active phlebitis, or a history of lower-extremity deep vein thrombosis; 7. Current use of sulfonylureas or nicorandil; 8. Expected survival \<1 year; 9. Concurrent participation in another clinical trial that has not yet reached its primary endpoint; 10. Pregnancy or breastfeeding; 11. Immunodeficiency, a known bleeding or coagulation disorder, sickle cell anemia, or active or uncontrolled infection; 12. Any other condition considered unsuitable for enrollment by the investigator