Epidemiological impact in the United States of a tissue-based definition of transient ischemic attack

Bruce Ovbiagele, Chelsea S. Kidwell, Jeffrey L. Saver

Research output: Contribution to journalArticle

83 Scopus citations

Abstract

Background and Purpose - The traditional definition of transient ischemic attack (TIA), based on an arbitrary time criterion of symptom resolution within 24 hours, is problematic because a large number of patients with traditionally defined TIAs have a relevant cerebral infarction on brain imaging. The objective of this study was to characterize the epidemiological impact of adopting a tissue-based definition of TIA. Methods - Estimates of the annual US incidence of traditionally defined transient ischemic attacks were abstracted from the literature. Models were then constructed for determining the frequency of brain injury in traditionally defined TIAs, derived from recent human studies of MR diffusion-weighted imaging (DWI) in transient cerebral ischemia. Results - Traditionally defined US TIA annual incidence rates ranged from 37 to 107 per 100 000 per year. Across 5 series, the raw frequency of DWI positivity in traditionally defined TIAs was 44%. Adjusting for an overrepresentation of longer-duration TIAs in MR series yielded an expected frequency of diffusion MRI positivity of 33% in unselected, traditionally defined TIAs. Applying this model to the US population in the year 2000 showed that adopting a tissue-based definition of TIA would decrease the annual number of events classified as TIAs from 179 840 to 120 493 and increase events classified as strokes from 821 181 to 880 520. Conclusions - Adopting a tissue-based definition of transient ischemic attack would reduce estimates of the annual incidence of TIA by 33% (sensitivity analysis range, 19% to 44%) and increase estimates of the annual incidence of stroke in the United States by 7% (range, 4% to 10%).

Original languageEnglish (US)
Pages (from-to)919-924
Number of pages6
JournalStroke
Volume34
Issue number4
DOIs
StatePublished - Apr 1 2003
Externally publishedYes

Keywords

  • Cerebral ischemia, transient
  • Epidemiology
  • Incidence
  • Magnetic resonance imaging, diffusion-weighted
  • United States

ASJC Scopus subject areas

  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine
  • Advanced and Specialized Nursing

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