The purpose of this study is to evaluate the protective effects of upper limb ischemic postconditioning on collateral circulationin young symptomatic intracranial atherosclerosis and the baseline characteristics of trial participants, as an open, randomized controlled, prospective controlled trial.

Stroke is a common cardia-cerebrovascular disease with high morbidity, disability and mortality rate. And more and more young patients account for the increasing morbidity. Among them, Symptomatic intracranial atherosclerotic stenosis（sICAS）is a major cause, especially in Asians.

Currently, traditional therapeutic methods present reluctant achievements on reducing stroke recurrence and pose threat on patients'health because of invasive operation and severe side effects. Therefore, other treatment methods are called for urgently. Remote ischemic post-conditioning refers to local or distal ischemia treatment after the occurrence of cerebral ischemia. Prior research has shown that repeatedly ischemic reperfusion have protective effect on lowering the occurrence rate of ischemic events of patients with carotid stenosis. However, in-depth research on cerebral protection and correlation with collateral circulation has not been proven in an open, definitive clinical trial.

Thus, the EPIC-sICAS trial will provide important information on the protective effects of upper limb ischemic post-conditioning on collateral circulation after cerebral Infarction. Hopefully to present us a very meaningful way to improve the patient's quality of life.

Inclusion Criteria:

1. Age between 18 to 45 Years old;
2. Symptomatic intracranial atherosclerotic stenosis (sICAS): cranial CTA/MRA/TCD/DSA confirm the diagnosis, patients got ischemic stroke or transient ischemic attack in the brain region supplied by the stenosis artery;
3. National Institutes of Health Stroke Scale(NIHSS) score 0-15
4. Written informed consent was signed.

Exclusion Criteria:

1. Cerebral hemorrhage and other parts of the active bleeding disease;
2. Severe aphasia, unable to express himself;
3. A history of brain tumor, brain trauma, cerebral embolism or other brain lesions;
4. Severe lesions of severe cardiac, liver or kidney disease, malignancy or other systemic organ dysfunction;
5. Blood Pressure< 90 mmHg/60 mmHg or >200 mmHg/110 mmHg after treatment;
6. Dementia and mental illness;
7. Using angiotensin-converting enzyme inhibitors;
8. A history of major surgery or trauma 4 weeks prior to admission;
9. Without informed consent.

Elimination Criteria：

1. Patients with poor compliance，refuse to take regular treatment and examination;
2. patients' condition get exacerbated, with NIHSS score elevate for more than 4.