Aspirin, anticoagulants, and hemorrhagic conversion of ischemic infarction: hypothesis and implications.

Anticoagulation may exacerbate possible tendencies for an ischemic infarction to become hemorrhagic. Little is known of any potential added risk of aspirin plus anticoagulation for such hemorrhagic transformation. A patient is reported who sustained a cerebral infarction from carotid artery disease and was treated with aspirin. Anticoagulation was begun and aspirin discontinued when the patient experienced a transient ischemic attack. Despite good control of anticoagulation, the patient sustained a hemorrhage at the site of infarction. The prolonged effects of aspirin combined with anticoagulants may have potentiated the conversion of an ischemic to a hemorrhagic infarction. Caution is advised when using anticoagulation immediately following aspirin therapy in patients with cerebral infarction.