For patients who have a noncardioembolic AIS while taking antiplatelet therapy, switching to warfarin is not indicated for secondary stroke prevention. III: No Benefit B-NR New recommendation. In patients taking aspirin at the time of baseline stroke in WARSS (Warfarin Aspirin Recurrent Stroke Study; n=181), there was no difference in recurrence of stroke between those randomized to remain on aspirin and those who In addition, post hoc analysis from the WASID trial found no difference in the primary outcome of ischemic stroke, brain hemorrhage, or vascular death in patients taking antiplatelet therapy at the time of their qualifying event who were subsequently randomized to warfarin.376,377 See Table LXXXIX in online Data Supplement 1. In patients with noncardioembolic ischemic stroke, treatment with triple antiplatelet therapy (aspirin+clopidogrel+dipyridamole) for secondary stroke prevention is harmful and should not be administered. III: Harm B-R New recommendation. The TARDIS trial (N=3096) was a multicenter, prospective, randomized, open-label trial conducted in Denmark, Georgia, New Zealand, and the United Kingdom of short-term triple antiplatelet therapy for secondary stroke prevention in patients with recent noncardioembolic ischemic stroke or TIA.350 The open-label treatment arms included aspirin+clopidogrel+dipyridamole versus either clopidogrel alone or aspirin and dipyridamole for 30 days from symptom onset. There was no benefit of triple therapy in prevention of stroke or TIA at 90 days (6% versus 7%; HR, 0.90 [95% CI, 0.67 1.20]; P=0.47). Moreover, there was a significant increase in risk of all hemorrhage (20% versus P=0.0063), and extracranial hemorrhage (HR, 2.37; 95% CI, 1.93 2.91; P<0.0001). See Table XLVIII in online Data Supplement 1. 6.6.2. Atrial Fibrillation COR LOE New, Revised, or Unchanged For most patients with an AIS in the setting of atrial fibrillation, it is reasonable to initiate oral anticoagulation between 4 and 14 days after the onset of neurological symptoms. 