A transient ischemic attack (TIA) is a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction. An ischemic stroke is a cerebral infarction. In POINT, eligibility is limited to brain TIAs and to minor ischemic strokes (with an NIH Stroke Scale [NIHSS] score less than or equal to 3).
TIAs are common, and are often harbingers of disabling strokes. Approximately 250,000-350,000 TIAs are diagnosed each year in the US. Given median survival of more than 8 years, there are approximately 2.4 million TIA survivors. In a national survey, one in fifteen of those over 65 years old reported a history of TIA, which is equivalent to a prevalence of 2.3 million in older Americans. Based on the prevalence of undiagnosed transient neurological events, the true incidence of TIA may be twice as high as the rates of diagnosis. Based on our review of the National Inpatient Sample for 1997-2003, there were an average of 200,000 hospital admissions for TIA each year, with annual charges climbing quickly in the period to $2.6 billion in 2003.
Composite endpoint of new ischemic vascular events: ischemic stroke, myocardial infarction or ischemic vascular death at 90 days.