Preventive Effectiveness of Aspirin on Recurrent Stroke

Multiple randomized trials indicated that antiplatelet agents, including aspirin alone, clopidogrel alone, and combined aspirin plus extended-release dipyridamole, can prevent recurrent stroke effectively. Previous findings indicated that aspirin plus extended-release dipyridamole is more effective than aspirin alone for the secondary prevention of stroke. Clopidogrel has been thought as effective as aspirin in the prevention of recurrent stroke. Thus, aspirin plus extended-release dipyridamole has been suggested to be superior to clopidogrel alone for preventing recurrent stroke based on indirect meta-analysis. However, the first clinical trial comparing aspirin plus extended-release dipyridamole and clopidogrel monotherapy directly revealed that aspirin plus extended-release dipyridamole is not different with clopidogrel alone in the risk of recurrent stroke significantly, which is not accordant to the early reports. Therefore, it is not known whether the more expensive agents like aspirin plus extended-release dipyridamole and clopidogrel could reduce the risk of recurrent stroke more effectively than aspirin alone. The 2011 American Heart Association/American Stroke Association guideline showed that aspirin alone, aspirin plus extended-release dipyridamole, and clopidogrel alone are acceptable choice for preventing recurrent stroke, but without a strong suggestion of preference. However, the 2012 update of the American College of Chest Physicians guideline indicated the superiority of aspirin plus dipyridamole for the secondary prevention of stroke compared with aspirin alone, but with a question about the truly beneficial effects on recurrent stroke with aspirin plus dipyridamole. A recent retrospective analysis of large patient numbers from Taiwan Stoke Registry (N = 10,792) indicated that aspirin regimen is not inferior to those more expensive agents such as aspirin plus dipyridamole or clopidogrel alone. In conclusion, based on the well-known efficacy and relative low cost, aspirin is effective as initial antiplatelet therapy for the secondary prevention of stroke in patients with ischemic stroke or transient ischemic attack.