In patients with ischemic stroke or TIA who are <3 months after an extracranial carotid or vertebral arterial dissection, it is reasonable to use either aspirin or warfarin to prevent recur- rent stroke or TIA.593,594 In patients with stroke or TIA and extracranial carotid or vertebral artery dissection who have recurrent events despite antithrombotic therapy, endovascular therapy may be consid- ered to prevent recurrent stroke or TIA.595,596 Synopsis Extracranial carotid or vertebral dissections can be the result of trauma or spontaneous. It is a relatively uncom- mon mechanism of ischemic stroke that is relevant mostly to younger individuals.597 The most common mechanism of stroke with extracranial dissection is artery-to-artery from an intraluminal thrombus, which is the rationale for using antithrombotic agents to decrease the rate of ischemic stroke.599 Although most dissections heal spontaneously, a subset of patients will undergo disease progression and arterial complications such as CLINICAL STATEMENTS AND GUIDELINES Kleindorfer Recommendation-Specific Supportive Text 1. The recommendation of using antithrombotic agents is based on expert opinion. Although arterial dissec- tion is a hemorrhagic process within the arterial wall, the most common mechanism for stroke is artery- from an intraluminal throm- bus. This is the rationale for using antithrombotic agents to decrease the rate of ischemic stroke.599 2. CADISS (Cervical Artery Dissection in Stroke Study) was an open-label trial that randomized 250 patients with extracranial dissection within 7 days from symptom onset to receive either antiplatelets or anticoagulants in the following 3 months.593 The specific agents and treatment regimens were left to the treating physician. 