Remote Ischemic Conditioning for Cognitive Impairment in Cerebral Small Vessel Disease

Inclusion Criteria: * Age 30-80 years. * Diagnosis of cerebral small vessel disease according to the Chinese Guidelines for the Diagnosis and Treatment of Cerebral Small Vessel Disease (2020). * Mild cognitive impairment with a Montreal Cognitive Assessment (MoCA) score of 18-25. * The patient or a legally authorized representative is able and willing to sign written informed consent. Exclusion Criteria: * Any condition that is unsuitable for remote ischemic conditioning, including soft tissue injury, limb deformity or vascular injury in the upper limb, bleeding disorders, or systolic blood pressure \> 200 mmHg. * History or presence of neurological or psychiatric disorders that may interfere with participation or outcome assessment, such as other cerebrovascular diseases, Parkinson's disease, or major depressive disorder. * Current or past severe systemic diseases deemed inappropriate for the study by the investigator, including but not limited to severe cardiovascular diseases (e.g., congestive heart failure, severe arrhythmia, myocardial infarction), severe hepatic diseases (e.g., cirrhosis), severe renal diseases (e.g., requiring hemodialysis or peritoneal dialysis), hematologic diseases with bleeding tendency (e.g., hemophilia), poorly controlled diabetes (blood glucose \> 16.8 mmol/L or \< 2.8 mmol/L) or with severe complications, active or uncontrolled systemic autoimmune diseases or primary/secondary immunodeficiency, or malignancy. * Laboratory abnormalities, including absolute neutrophil count \< 1.5 × 10⁹/L, platelet count \< 100 × 10⁹/L, hemoglobin \< 90 g/L, AST or ALT \> 2.5 × upper limit of normal (ULN), total bilirubin \> 1.5 × ULN, or serum creatinine \> 1.5 × ULN. * Coagulation abnormalities, including for patients not on anticoagulant/antithrombotic therapy: INR \> 1.7 or APTT \> 1.25 × ULN; and for patients on anticoagulant/antithrombotic therapy: INR \> 3.0 or APTT \> 1.5 × ULN. * Positive tests for hepatitis B with detectable HBV-DNA, or positive serology for hepatitis C, syphilis (TPAb/RPR), or HIV. * Pregnant or breastfeeding women. * Contraindications to MRI (e.g., pacemaker or other metallic implants, severe claustrophobia). * Participation in another clinical trial within 3 months prior to enrollment. * Severe trauma or major surgery within 3 months before remote ischemic conditioning, or planned surgery during the study period (except minor procedures and laparoscopic procedures performed within 4 weeks before baseline). * History of substance abuse or alcoholism within 1 year prior to enrollment. * Any other condition that may increase risk or interfere with the interpretation of study results, as judged by the investigator.