Prodromal Transient Ischemic Attack or Minor Stroke and Outcome in Basilar Artery Occlusion

BACKGROUND The presence of prodromal transient ischemic attacks (TIAs) has been associated with a favorable outcome in anterior circulation stroke. We aimed to determine the association between prodromal TIAs or minor stroke and outcomes at 1 month, in the Basilar Artery International Cooperation Study, a registry of patients presenting with an acute symptomatic and radiologically confirmed basilar artery occlusion. METHODS A total of 619 patients were enrolled in the registry. Information on prodromal TIAs was available for 517 patients and on prodromal stroke for 487 patients. We calculated risk ratios and corresponding 95% confidence intervals (CIs) for poor clinical outcome (modified Rankin Scale score ≥4) according to the variables of interest. RESULTS Prodromal minor stroke was associated with poor outcome (crude risk ratio [cRR], 1.26; 95% CI, 1.12-1.42), but TIAs were not (cRR, .93; 95% CI, .79-1.09). These associations remained essentially the same after adjustment for confounding variables. CONCLUSIONS Prodromal minor stroke was associated with an unfavorable outcome in patients with basilar artery occlusion, whereas prodromal TIA was not.