Background and purpose: clinical scores help predict outcome after transient ischemic attack (TIA), and imaging studies may improve the accuracy of predictions. Intracranial large vessel occlusion (LVO) predicts poor outcome after stroke, but the natural history of symptomatic intracranial LVO in patients with TIA is unknown.
Methods: we studied patients presenting with TIA in the STOP Stroke Study, a prospective imaging-based study of stroke outcomes. All patients underwent brain CTA. If an intracranial vascular occlusion was found in an appropriate territory to account for clinical findings, then it was judged to be a symptomatic LVO. Baseline characteristics, follow-up events, and outcomes were collected. Characteristics of patients with and without LVO were compared using χ(2) and t tests. Predictors of LVO were analyzed by univariate and multivariate analysis. LVO was assessed as a predictor of asymptomatic outcome (modified Rankin scale [mRS] score, 0), poor outcome (mRS score ≤ 3), and increase in mRS score over the study period.
Results: of 97 patients with TIA, 13 (13%) had symptomatic intracranial LVO. Patients with LVO had higher baseline NIHSS on emergency department arrival, which was an independent predictor of LVO (OR, 1.15 per point; 95% CI, 1.02-1.29; P=0.02). Patients with LVO were more likely to have an increase in mRS score during the 90-day follow-up (P=0.03). LVO independently predicted an increase in mRS score (OR, 4.76; 95% CI, 1.23-18.43; P=0.02) and was a borderline predictor of poor outcome (mRS score ≥ 3; OR, 5.07; 95% CI, 0.92-28.03; P=0.06).
Conclusions: LVO is found in >1 in 10 patients presenting with TIA and predicts a decline in functional status, likely attributable to new brain ischemia.