This randomized, double-blind, sham-controlled trial aims to evaluate the effect of remote ischemic conditioning (RIC) on cognitive function in patients with cerebral small vessel disease-related mild cognitive impairment. Forty eligible participants will be randomized 1:1 to receive either RIC or sham RIC twice daily for 90 days in addition to standard medical therapy. The primary outcome is the change in Montreal Cognitive Assessment (MoCA) score from baseline to 90 days. Secondary outcomes include changes in white matter hyperintensity burden and diffusion tensor imaging metrics on MRI, EEG functional connectivity, and activities of daily living.

Cerebral small vessel disease (CSVD) is a leading cause of vascular cognitive impairment, characterized by white matter hyperintensities, lacunes, and microbleeds on MRI. Current treatment options for CSVD-related cognitive impairment are limited, and there is a critical need for safe, noninvasive interventions that can improve cognitive function and delay disease progression.

Remote ischemic conditioning (RIC) is a noninvasive, low-cost procedure induced by intermittent cuff inflation on a limb to produce brief episodes of ischemia and reperfusion. Experimental and clinical studies suggest that RIC can improve cerebral perfusion, protect the neurovascular unit, and modulate inflammatory and endothelial pathways, making it a promising strategy for CSVD.

In this single-center, randomized, double-blind, sham-controlled trial, we will enroll 40 patients with CSVD-related mild cognitive impairment. Participants will be randomized to receive either RIC (cuff inflation to 200 mmHg for 5 minutes followed by 5 minutes of reperfusion, 5 cycles per session) or sham RIC (cuff inflation to 60 mmHg, 5 cycles per session). The intervention will be administered twice daily for 90 days, in addition to standard medical therapy.

Cognitive function will be assessed by the Montreal Cognitive Assessment (MoCA). MRI will be used to quantify white matter hyperintensities and diffusion tensor imaging parameters, and EEG will be used to evaluate functional connectivity. Activities of daily living and safety outcomes will also be recorded. This study will provide clinical and mechanistic evidence on whether RIC can prevent or ameliorate cognitive impairment in patients with CSVD.

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.

There is no current plan to share individual participant data (IPD) from this trial with external researchers. De-identified, aggregate study results will be reported in publications and presentations in accordance with institutional and national regulations.