Remote ischemic conditioning (RIC) is a noninvasive strategy in which one or more cycles of brief and transient limb ischemia confers protection against prolonged and severe ischemia in distant organs.This study aimed to investigate whether RIC is safe and effective in patients with AIS complicating ACS

Remote ischemic conditioning (RIC) is a noninvasive strategy in which one or more cycles of brief and transient limb ischemia confers protection against prolonged and severe ischemia in distant organs (e.g., brain and heart).It has been demonstrated to be an effective strategy to reduce plasma myocardial enzyme, infarct volume, and incidence of post-ACS heart failure in patients with ACS. Additionally, recent studies have found that RIC was safe and feasible in patients with AIS even in those caused by large artery occlusion and treated with reperfusion therapy, and it might benefit AIS patients by reducing the risk of brain tissue infarction and improving functional outcomes. To date, however, it is still unknow whether RIC, a systematic protective strategy, could benefit patients with AIS complicating ACS.This study aimed to investigate whether RIC is safe and effective in patients with AIS complicating ACS.

Inclusion Criteria:

• age≥60yo
• AIS within 24 hours after symptom onset which meet the diagnostic criteria for acute ischemic stroke of the 2013th ASA guidelines, AIS was defined as a clinical episode of neurological dysfunction caused by focal cerebral infarction that can be detected on imaging(e.g.,computed tomography or magnetic resonance imaging of head)
• ACS within 24 hours of stroke onset , and ACS contains ST-segment elevation myocardial infarction, non-ST-elevation myocardial infarction, unstable angina and it was defined when there is a rise and/or fall of plasma cardiac biomarkers (e.g., myocardial enzyme，cardiac troponin I), along with supportive evidence in the form of typical symptoms (e.g., chest pain), suggestive electrocardiographic changes, or imaging evidence of new loss of viable myocardium or new regional wall motion abnormality
• The patients missed the opportunity of or contradicted to reperfusion therapy (i.e., intravenous thrombolysis and endovascular treatments) for both AIS and ACS.
• Informed consent obtained

Exclusion Criteria:

• Unstable vital signs
• Prior ipsilateral stroke with residual deficits
• AIS caused by cardioembolism, suspicious arterial dissection, intracranial sinus thrombolysis, vasculitis, and moyamoya disease.
• Intracranial bleeding.
• Advanced malignancy.
• Uncontrolled hypertension (defined as systolic blood pressure ≥200 mm Hg despite medications at enrollment).
• Any vascular, soft tissue, or orthopedic injury (eg, superficial wounds and fractures of the arm) that contraindicated bilateral arm ischemic preconditioning.
• Peripheral vascular disease that affecting the upper limbs' arteries
• Any disorder that could potentially increase pre-stroke myocardial enzyme concentrations (eg, percutaneous coronary intervention or myocardial infarction within the previous 6 weeks)
• Coronary artery stenosis requiring coronary bypass surgery for the index event within 3 months; or severe heart failure requiring mechanical ventilation or use of an intra-aortic balloon pump
• Taking drugs in the study period or are participating in other clinical trials.
• Severe psychiatric disease.
• Patients who cannot keep treatment or follow-up.

The RIC and sham procedure were performed by using identical devices with different cuff pressures (200mmHg versus 60 mmHg). Patients, investigators, and raters were all blinded to the treatment assignment.