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. Recommendation-Specific Supportive Text 1. In the WASID trial (Warfarin-Aspirin Symptomatic Intracranial Disease), warfarin (target INR, 2 3) compared with aspirin 650 mg twice a day was found to have a higher rate of major hemorrhages (relative difference, 5.1%) and all-cause death (rela- tive difference, 5.4%) but did not prevent more pri- mary end points (stroke, ICH, vascular death) (22% in both arms at a mean follow-up of 1.8 years) or ischemic strokes in the territory of the stenotic artery (2-year rate: 15% for aspirin versus 13% for The optimal dose of aspirin for second- ary prevention in patients with ICAS has not been determined, but doses <1300 mg/d are probably effective given that lower doses of aspirin have been shown to be effective for secondary prevention in trials of heterogeneous causes of stroke and that patients in the medical arm of the SAMMPRIS trial were treated with 325 mg aspirin once daily alone after the first 90 days with favorable results.336 2. Support for the use of short-term combination aspirin and clopidogrel for secondary prevention in patients with severe ICAS comes from post hoc analyses of clinical trials and RCTs studying surro- gate end points for stroke. 