Remote Ischemic Preconditioning for Aute Type A Aortic Dissection Surgery

Inclusion Criteria: 1. Age ≥18 years, with no restriction on sex; 2. Diagnosis of acute Type A aortic dissection requiring emergency surgery (symptom onset \<14 days); 3. Ability to understand the study objectives, voluntary provision of written informed consent by the patient or a legally authorized representative, and willingness to comply with follow-up. Exclusion Criteria: 1. Traumatic or iatrogenic aortic dissection; 2. Previous open cardiac or thoracic aortic surgery; 3. Severe preoperative dysfunction of vital organs, such as persistent deep coma, abdominal compartment syndrome, or circulatory failure; 4. Severe comorbidities, including myocardial infarction within the past 7 days, stroke within the past 2 months; end-stage renal disease (eGFR \<30 ml/min/1.73 m²); end-stage liver disease (total bilirubin \>342 μmol/L or INR \>2.0); 5. Evidence of ischemia in the limb planned for intervention, such as decreased skin temperature, pain, pallor, with or without sensory disturbance, paralysis, or diminished/absent pulses; or severe deformity or prior arteriovenous surgery at the intervention site; 6. Peripheral arterial disease involving the limbs, Raynaud phenomenon, active phlebitis, or a history of deep vein thrombosis of the lower extremities; 7. Current use of sulfonylurea oral hypoglycemic agents or nicorandil; 8. Life expectancy \<1 year (e.g., advanced malignancy); 9. Participation in another clinical trial without having reached its primary endpoint; 10. Pregnancy or lactation; immunodeficiency (e.g., HIV positivity, history of organ transplantation); known bleeding disorders, coagulation abnormalities, or sickle cell anemia; active or uncontrolled infection; 11. Other severe physical or psychiatric disorders, or laboratory abnormalities, which in the investigator's judgment may increase risk or interfere with study outcomes, rendering the patient unsuitable for enrollment.