How is transient ischemic attack (TIA) defined?

Updated: Dec 03, 2018
  • Author: Ashish Nanda, MD; Chief Editor: Andrew K Chang, MD, MS  more...
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In 2009, the American Heart Association and the American Stroke Association (AHA/ASA) published a scientific statement that revised the definition of transient ischemic attack (TIA) to the following:  "a transient episode of neurologic dysfunction caused by focal brain, spinal cord or retinal ischemia without acute infarction." [1]  Prior to this revised definition, TIA was often operationally defined based on symptom duration lasting less than 24 hours, with typical episodes lasting less than 1 hour. The de-emphasis on duration was due to multiple studies demonstrating that up to 50% of classically defined TIAs showed brain injury on magnetic resonance imaging (MRI).

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