Limb Remote Ischemic Conditioning and Cerebrovascular Reserve

Inclusion Criteria: \- (1)Symptomatic intracranial arterial stenosis measuring \>=50% by angiography or \>=70% by ultrasound, CT angiography (CTA), or magnetic resonance angiography (MRA);(2)Age range 18-80 years;(3)Compared with normal brain tissue, the reduction of cerebral glucose metabolism (CGM) and/ or cerebral blood flow (CBF) in the focal area\>=8%;(4)Stable vital signs, normal renal and hepatic functions; (5)No hemorrhagic tendency;(6)Subject or his or her legally authorized representative was able to provide an informed conised. Exclusion Criteria: -(1)Uncontrolled hypertension (defined as systolic blood pressure\>=200 mmHg despite medications at enrollment); (2)Any vascular, soft tissue, or orthopedic injury (eg, superficial wounds and fractures of the arm) that contraindicated bilateral arm ischemic preconditioning;(3)Peripheral vascular disease (especially subclavian arterial and upper limb artery stenosis or occlusion); (4)Hematologic disease;(5)Severe or unstable concomitant disease;(6)Can not tolerate LRIC treatment;(7)No informed consent.