The study composed of two parts. The first part composed of prospective clinical registry for CAO. The second part compose of a prospective superiority trial, rater blinded, with 1:1 randomization to evaluate the clinical efficacy of interventional therapy for CAO. Eligible candidates for CAO revealed by CT, ultrasonography, angiography, or magnetic resonance imaging (MRI), with abnormal brain perfusion demonstrated by CT perfusion study (CTP) or MRI, will be enrolled in to study. If the participants agreed for randomization, participants will be randomized into 2 groups: the optimal medical therapy (OMT) group and the endovascular revascularization plus optimal medical therapy (ER+OMT) group. The primary end-point of the trial is the NCF improvement at 3 months and thereafter up to 12 months. The secondary endpoint includes: cumulative incidence of death and stroke within 30 days after the procedure; death or ipsilateral stroke between 31 days and 1 year; major stroke, ischemic stroke, or hemorrhagic stroke within 30 days after the procedure; major stroke, ischemic stroke, or hemorrhagic stroke between 31 days and 1 year; cognitive function measured by CANTAB; change of cerebral perfusion measured by CTP; target vessel revascularization rate; technique success rate; procedure success rate; and major procedure complication.