Attack Interval Is the Key to the Likely Pathogenesis of Multiple Transient Ischemic Attacks

<b><i>Introduction:</i></b> The aim of this study was to test the hypothesis that the attack interval of multiple transient ischemic attacks (TIAs) is correlated with the underlying pathogenesis of ischemia. <b><i>Methods:</i></b> Patients with multiple TIAs, defined as 2 or more motor deficits within 7 days, were studied. The attack interval between the last 2 episodes was classified into 3 groups: 2 episodes within an hour (Hour group), over hours within a day (Day group), and over days within a week (Week group). Patients with a lacunar syndrome, no cortical lesions, and no embolic sources were recognized as having a small vessel disease (SVD) etiology for their multiple events. <b><i>Results:</i></b> Of 312 TIA patients admitted over a 9-year period, 50 (37 males, 13 females, mean 67.6 years) had multiple TIAs. Twelve patients were classified as being within the Hour group, 23 within the Day group, and 15 within the Week group. Lacunar syndromes were observed in 30 (75%, 35%, and 67%), embolic sources were detected in 28 (25%, 65%, and 67%), and a high signal lesion on diffusion-weighted imaging was depicted in 30 (75%, 48%, and 67%) patients (18 cortical, 11 subcortical, and one cerebellar). Patients in the Hour group had a significantly higher prevalence of SVD etiology (75%) than those in the Day and Week groups (30%, <i>p</i> = 0.0165; 27%, <i>p</i> = 0.0213, respectively). Four patients had a subsequent stroke within 7 days. <b><i>Conclusion:</i></b> Attack intervals of multiple TIAs may be correlated with the underlying pathogenesis of ischemia. Two motor deficits within an hour are more likely to suggest a SVD etiology.