Effect of Clopidogrel Added to Aspirin in Patients with Atrial Fibrillation

A randomized trial enrolled 7554 patients with atrial fibrillation who were at increased risk of stroke but not candidates for vitamin K antagonists. Participants were assigned to aspirin or aspirin plus clopidogrel. At a median of 3.6 years, the risk of major vascular events decreased significantly with clopidogrel, primarily because of reduced risk of stroke. The risk of major bleeding increased significantly with clopidogrel. At a median of 3.6 years, the risk of major vascular events decreased significantly with clopidogrel, primarily because of reduced risk of stroke. The risk of major bleeding increased significantly with clopidogrel. Atrial fibrillation is a common cardiac arrhythmia that increases the risk of stroke by a factor of five. 1 Adjusted-dose vitamin K antagonists and antiplatelet agents reduce the risk of stroke by 64% and 22%, respectively. 2 As compared with aspirin, vitamin K antagonists reduce the risk of stroke by 38% but more than double the risk of intracranial hemorrhage and increase the risk of major extracranial hemorrhage by 70%. They do not reduce mortality from any cause or from vascular causes. 2 , 3 On the basis of these data, vitamin K antagonists are recommended for patients at higher risk for stroke, and . . .