Protective Effects of RIC in Elderly With Acute Ischemic Stroke Complicating Acute Coronary Syndrome

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.