To determine whether status of dominant vertebral artery could affect clinical outcome in patients with symptomatic basilar artery occlusion (BAO).

We reviewed patients with symptomatic BAO who underwent endovascular treatment at the institute between January 2007 and July 2014. Patients were categorized into 2 groups according to functional outcome and baseline characteristics, treatment related factors were compared. Variables including clinical and imaging parameters were also compared according to the dominant V1 lesion.

Fifty-nine of 101 patients underwent endovascular treatment and 23 patients (39.0%) showed favorable outcome (modified Rankin score ≤3 at 3 month). Younger age, male sex, lower baseline NIHSS score, higher PC-ASPECTS, absence of hemorrhagic transformation, shorter procedure time, and complete recanalization were associated with favorable outcome. Procedure time tended to be longer in patients with dominant V1 lesion (130.0; range, 105.0–179.0 vs. 101.5; range, 48.0–138.0, P=0.05). Among patients with large artery disease (LAD), higher initial NIHSS, and clinical manifestation of decreased mental status were significantly associated with dominant V1 lesion. Endovascular procedure time tended to be longer, distal basilar occlusion tended to be more frequent, and proportion of the patients with complete recanalization tended to be less in patient with dominant V1 lesion. Poor outcome tended to be more frequent in dominant V1 lesion with LAD (88.9% vs. 42.9%, P=0.05). These findings were comparable in patients who underwent mechanical thrombectomy.

Dominant V1 steno-occlusion may be associated with poor functional outcome in patients with the symptomatic BAO. Status of dominant VA and various treatment strategy should be considered when performing endovascular treatment for recanalization in patients with symptomatic BAO.