The SAMMPRIS suggested that aggressive treatment was superior to intravascular stenting in patients with severe symptomatic intracranial atherosclerotic stenosis (ICAS) due to high complication rate in patients in stenting group. However the intravascular therapy is going on because of low complication rate in considerable Chinese studies coming from several high volume stroke centers. Given to 12.2% patients failing to aggressive medical therap in the SAMMPRIS study, it is imperative to performing an multiple prospective registry study of stenting for patients with ICAS in China.

This study is a multicentre prospective single-arm registry study and the protocol is approved by the ethics committee at the coordinating centre and by the local institutional review board at each participating centre. This study is initiated by the investigators, with 20 participating stroke centres (see online supplementary appendix II), and plans to recruit 300 consecutive patients who meet the inclusion and exclusion criteria. After the enrolment, all participants would be evaluated at baseline, day 4, day 30, months 6, months 9 and year 1 (see online supplementary appendix I). The Wingspan stent system is provided by the Boston Scientific company and the Apollo stent is provided by the MicroPort Company, but they will not participate in data collection, analysis, editing or make decisions about the publication. This study is sponsored and conducted by the Cerebrovascular Disease Center of Tiantan Hospital in addition to its responsibility for data analysis. An independent Data and Safety Monitoring Board (DSMB) oversees the conduction, safety and efficacy of the study.

Inclusion Criteria:

18~80 years old; Primary or recurrent symptomatic intracranial arteriostenosis ineffective through the internal medicine treatment (i.e. stroke or TIA within 90 days during the treatment with at least one anti-thrombotic drugs and vascular risk factor intervention (e.g. hypotensors for hypertension and hypolipidemics for hyperlipidemia);

• 70% stenosis of intracranial responsible angiopathic area under the DSA angiography (as judged through the WASID method);
• 2mm diameter and <15mm length of ill blood vessel, but normal distal blood vessel

Poor blood circulation in the side branch of responsible angiopathic area under the radiography within one week before the operation:

Blood flow rate peak of ≥200cm/s at the systolic phase under the transcranial doppler ultrasonic examination (TCD); and Low perfusion in the responsible angiopathic area under the skull perfusion CT (i.e. at a decrease of more than 30% over the perfusion at the opposite side); or <4 scores of blood circulation in the side branch under the DSA; or Hemodynamic ischemic foci under the skull MRI; or Poor blood circulation in the side branch of responsible angiopathic area under the single photon emission computer tomography (SPECT)

Exclusion Criteria:

• >50% stenosis beyond the responsible intracranial artery Acute ischemic stroke within 3 weeks Obstruction of bypass branch of ill simple carrier artery under the skull MRI Non-atherosclerotic lesion: MoyaMoya disease, any known vascular inflammatory disease, herpes zoster, angiopathy caused by the chicken-pox, herpes zoster or other viruses, neurosyphilis, other intracranial infections, radioactive angiopathy, maldevelopment of fibrous muscle, sickle-cell anemia, neurofibroma, benign angiopathy of central nervous system, postpartum angiopathy, suspicious vasospasm, and recanalization of suspicious thrombosis Intracranial hemorrhage in the angiopathic area within 6 weeks; Potential source for cardiac embolism Concomitant intracranial tumor, aneurysm or intracranial arteriovenous malformation >50% stenosis of extracranial carotid or vertebral artery at the same side as intracranial angiopathic area; Known contraindications for heparin, Aspirin, Clopidogrel, anesthetics and contrast medium; hemoglobin <10g/dl, and blood platelet count <100000 Serious neural dysfunction due to the responsible angiopathy as the sequel of cerebral infarction (mRS≥3) International normalization ratio (INR) >1.5 (irreversible), uncorrectable hemorrhagic factor; life expectancy due to the illness <1 year Pregnant/lactating women Inapplicable for intravascular treatment in the viewpoints of investigators

Symptomatic ischemic cerebrovascular disease caused by Intracranial atherosclerotic atherosclerosis.Patients with ≥70% stenosis of angiopathic area symptomatic ICAD caused by hypoperfusion combined with poor collateral flow.