Risk Factor Management In patients with a stroke or TIA attributable to 50% to 99% stenosis of a major intracranial artery, maintenance of SBP below 140 mmHg, high-intensity statin therapy, and at least moderate physical activity are recom- mended to prevent recurrent stroke and Angioplasty and Stenting In patients with severe stenosis (70%-99%) of a major intracranial artery and actively pro- gressing symptoms or recurrent TIA or stroke after institution of aspirin and clopidogrel therapy, achievement of SBP <140 mmHg, and high- intensity statin therapy (so-called medical failures), the usefulness of angio- plasty alone or stent placement to prevent ischemic stroke in the territory of the stenotic artery is unknown.350 352 3: Harm A In patients with stroke or TIA attributable to severe stenosis (70% 99%) of a major intracranial artery, angioplasty and stenting should not be performed as an initial treat- ment, even for patients who were taking an antithrombotic agent at the time of the stroke 3: Harm B-NR In patients with a stroke or TIA attributable to moderate stenosis (50% 69%) of a major intracranial artery, angioplasty or stenting is associated with excess morbidity and mortal- ity compared with medical management Other Procedures Benefit B-R In patients with stroke or TIA attributable to 50% to 99% stenosis or occlusion of a major intracranial artery, extracranial-intracra- nial bypass surgery is not recommended.361 Synopsis ICAS is a common cause of stroke worldwide with a high rate of recurrent stroke.362 Severity of stenosis is a strong predictor of risk of recurrent stroke in the ter- ritory of the stenotic artery, with 1-year rates as high as Therapeutic tri- als have demonstrated that for most patients with ICAS, antithrombotic therapy and vascular risk factor control are effective for stroke prevention. However, there may be a subset of patients (eg, those with low flow or poor collaterals) who have an even higher risk of recurrent stroke despite medical therapy.357,363,364 Current research is focused on identifying characteristics of patients with ICAS at highest risk and studying new therapies for stroke prevention. 