2.1. Subjects

Chinese IntraCranial AtheroSclerosis Study (CICAS) is a prospective, multicenter, hospital‐based study. From October 2007 to June 2009, 2864 patients with noncardioembolic IS or transient ischemic attack (TIA) in 22 Chinese general hospitals were enrolled.

Patients enrolled had the onset of symptoms within 7 days and were between 18 and 80 years old. Patients were excluded if they were clinically unstable, required close monitoring, unable to comply with magnetic resonance imaging (MRI). We excluded patients with cardioembolic risk factors (atrial fibrillation, atrial flutter, valvular heart disease, bioprosthetic or mechanical heart valve replacement, myocardial infarct within the past month, sick sinus syndrome, dilated cardiomyopathy, endocarditis, etc.) or other causes of IS as well as undetermined causes. Patients who were diagnosed as TIA, patients without available MR images identifying new cerebral infarct or responsible artery of acute infarcts, patients with IS involving posterior circulation or unilateral internal carotid artery territory or unilateral anterior cerebral artery territory or bilateral anterior circulation, patients with IS involving both anterior and posterior circulation, and patients who underwent angioplasty or stent implantation of intracranial or extracranial artery were also excluded. Finally, 967 patients with noncardiogenic IS in unilateral MCA territory were enrolled (Figure 1). The study protocol was approved by the ethics committee of Beijing Tiantan Hospital, and all participants or their legal proxies signed written informed consent for involvement of the research.

Flow chart of patient enrollment

Clinical information including hypertension, diabetes mellitus, hyperlipidemia, history of coronary heart disease (CHD), smoking history, and heavy drinking history were defined according to the methods in previous paper (Pu et al., 2013). Primary symptoms and signs at admission, National Institutes of Health stroke scale score at admission and discharge, modified Rankin Scale (mRS) at discharge were also recorded. Disability was defined as mRS ≥2.

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.