Neurologic Examination at 24 to 48 Hours Predicts Functional Outcomes in Basilar Artery Occlusion Stroke

Abstract

Background and Purpose - Accurate long-term outcome prognostication in basilar artery occlusion strokes may guide clinical management in the subacute stage. We determine the prognostic value of the follow-up neurological examination using the National Institutes of Health stroke scale (NIHSS) and identify 24- to 48-hour NIHSS risk categories in basilar artery occlusion patients. Methods - Participants of an observational registry of radiologically confirmed acute basilar artery occlusion (BASICS [Basilar Artery International Cooperation Study]) with prospectively collected 24- to 48-hour NIHSS and 1-month modified Rankin scale scores were included. Uni- and multivariable modeling were performed to identify independent predictors of poor outcome. Predictive powers of baseline and 24- to 48-hour NIHSS for poor outcome (modified Rankin scale, 4-6) and 1-month mortality were determined by receiver operating characteristic analyses. Classification and regression tree analysis was performed to identify risk groups. Results - Three hundred seventy-six of 619 BASICS participants were included, of whom 65.4% had poor outcome. In multivariable analyses, 24- to 48-hour NIHSS (odds ratio=1.28 [1.21-1.35]), history of minor stroke (odds ratio=2.64 [1.04-6.74], time to treatment >6 hours (odds ratio=3.07 [1.35-6.99]), and age (odds ratio=1.02 [0.99-1.04]) were retained in the final model as predictors of poor outcome. Prognostic power of 24- to 48-hour NIHSS was higher than baseline NIHSS for 1-month poor outcome (area under the curve, 0.92 versus 0.75) and mortality (area under the curve, 0.85 versus 0.72). Classification and regression tree analysis identified five 24- to 48-hour NIHSS risk categories with poor outcome rates of 9.4% (NIHSS 0-4), 36% (NIHSS 5-11), 84.3% (NIHSS 12-22), 96.1% (NIHSS 23-27), and 100% (NIHSS≥28). Conclusions - Twenty-four- to 48-hour NIHSS accurately predicts 1-month poor outcome and mortality and represents a clinically valuable prognostic tool for the care of basilar artery occlusion patients.