6. Subject treatable within 24 hours from symptoms onset or time last seen at baseline (i.e., subjects who have stroke symptoms upon awakening will be considered to have their "onset" at beginning of sleep; subjects who are found with new stroke symptoms and are unable to communicate the actual time of symptoms onset will be considered to have their "onset" at the last time they were seen well). Treatment initiation is defined as groin or other access site puncture. Symptoms onset include vertigo, diplopia, midline ataxia, visual loss, sensory or motor deficits.