Are there clinical factors that help identify patients with ESUS who may benefit from anticoagulation rather than antiplatelet treatment for secondary prevention? One of the primary challenges in identifying treat- ments to reduce the risk of second stroke in patients with ESUS is the difficulty of clearly defining criteria for ESUS diagnosis. Future trials should address these topics: The use of different strategies for long-term arrhyth- mia detection and their impact on ESUS diagnosis criteria. The use of additional cardiac markers of atrial pathology, including atrial size, and their impact on ESUS diagnosis criteria, secondary stroke risk, and response to anticoagulation. 5.19. Use of Antithrombotic Medications in Secondary Stroke Prevention As described in prior sections of this guideline, recom- mendations for secondary stroke prevention have been constructed on the basis of the best evidence among patients with a specific cause of their initial ischemic stroke. For patients with noncardioembolic ischemic stroke who do not have a specific identified cause, ques- tions about optimal antithrombotic medication use for secondary prevention may thus arise. In general, when those specific antithrombotic recommendations vary slightly from the general recommendations that follow in this section, the most specific recommendation should be prioritized. Recommendations for Antithrombotic Medications Referenced studies that support recommendations are summarized in online Data Supplements 57 59. COR LOE Recommendations In patients with noncardioembolic ischemic stroke or TIA, antiplatelet therapy is indicated in preference to oral anticoagulation to reduce the risk of recurrent ischemic stroke and other cardiovascular events while minimizing the risk For patients with noncardioembolic ischemic stroke or TIA, aspirin 50 to 325 mg daily, clopidogrel 75 mg, or the combination of aspi- rin 25 mg and extended-release dipyridamole 200 mg twice daily is indicated for secondary prevention of ischemic stroke.