Transient neurological attack before vertebrobasilar stroke

Patients with vertebrobasilar (VB) circulation ischemia can present with nonspecific symptoms, which complicate the distinction of transient ischemic attack (TIA) from other benign disorders. According to previously accepted classifications, typical TIA does not occur with VB symptom such as vertigo, diplopia, or dysarthria in isolation. However, there is a lack of evidence to support this hypothesis.

This hospital-based study included 214 consecutive patients with acute ischemic VB stroke. We defined transient neurological attacks (TNAs) as temporary (<24h) episodes with neurological symptoms, and further divided them into TIA, nonspecific TNA, or other specific disorder groups. We investigated the incidence and clinical symptoms of TNAs within 3months prior to the stroke episode, and comparisons were made between patients with and without previous TNA history with respect to their background and stroke profiles.

Among 214 patients with VB stroke, 56 (26.2%) had previous TNAs. Six of them were diagnosed with other specific disorders and excluded from the analysis. The remaining 33 and 17 were diagnosed with TIA and nonspecific TNA, respectively. Twenty-one (42.0%) had attacks with a nonfocal symptom in isolation, and acute infarction in neuroimaging was confirmed in 4 of these patients. Vertigo was the most frequent nonspecific TNA symptom. Patients with prior TNA had a significantly higher rate of atherothrombotic stroke than those without TNA (40.0% vs. 21.5%, P=0.009).

A considerable fraction of TIAs due to VB circulation ischemia may be overlooked among clinically nonfocal TNAs.