Stroke is the leading cause of long-term adult disability in the United States. An ischaemic stroke — accounting for 87% of all strokes — occurs when a blood clot blocks a cerebral artery. A haemorrhagic stroke occurs when a blood vessel ruptures, bleeding directly into brain tissue. Both types cause rapid neurological injury that is time-dependent. The FAST acronym captures the cardinal signs: Face drooping, Arm weakness, Speech difficulty, Time to call 911. Intravenous thrombolysis with alteplase can dissolve clots when administered within 4.5 hours of onset; mechanical thrombectomy — catheter-based clot removal — is effective up to 24 hours in selected patients. Time is brain: approximately 1.9 million neurons die each minute a large-vessel stroke is untreated.
