Etiology, Duration, and Prognosis of Transient Ischemic Attacks

CONTEXT: A transient ischemic attack (TIA) has been arbitrarily defined as a focal cerebral ischemic deficit lasting less than 24 hours. OBJECTIVE: To determine if TIAs of short duration (<1 hour) and long duration (1 hour to <24 hours) differ from each other and from ischemic stroke (IS). DESIGN, SETTING, AND PATIENTS: Inception cohorts of 1429 patients with acute TIAs and 5206 patients with IS were prospectively documented in 15 German medical centers with neurology departments and acute stroke units. Outcome after 3 months was assessed in 72.8% of the patients with TIAs. MAIN OUTCOME MEASURES: Risk factor distribution, etiology, and prognosis of TIAs and IS. RESULTS: Patients with TIAs, especially those with symptoms lasting less than 1 hour, were significantly more likely to have a history of TIAs and less likely to have diabetes mellitus, arterial hypertension, or atrial fibrillation at admission compared with those with IS. Cardioembolic etiologies were less frequent and unknown etiologies more frequent among patients with TIAs than those with IS. Functional outcome and mortality did not differ significantly in patients with TIAs of different durations. CONCLUSION: This study demonstrates differences in comorbidity and etiology among patients with TIAs of different durations and IS.