Abstract TP58: NIH Stroke Scale as Predictor of Prognosis in Posterior Circulation Stroke

Abstract

BACKGROUND: The NIHSS is an indispensable tool that aids in the decision-making of acute stroke management. Posterior circulation strokes often have lower NIHSS scores. This may result in withholding treatment with IV tPA and poor outcome in this population. We aimed to assess the predictive value of the NIHSS on poor functional outcome in anterior circulation (AC) versus posterior circulation (PC) strokes. METHODS: This was a retrospective analysis of a prospectively collected database from a single center. Adult patients admitted to the stroke service with acute ischemic stroke from January 2000 through December 2011 were included. Data collected included demographics, initial NIHSS, vascular distribution of infarct, complications, and outcome at 3 months. Since this study focused on minor strokes, death or disability was defined as death or a score of < 18 on the modified Barthel Index (BI) scale. RESULTS: The analysis included 1,197 patients with AC stroke and 372 with PC stroke. Table 1 lists the characteristics of the two groups. The NIHSS score on admission was lower in PC stroke and the majority (63%) of PC stroke patients had baseline NIHSS scores < 4. AC stroke patients were more likely to be treated with IV tPA or endovascular treatment. Surprisingly, 15% of patients with posterior circulation strokes and admission NIHSS score < 4 had death or disability at 3 months. On multivariable analyses, higher NIHSS score was an independent predictor of death or disability at 3 months in both AC (OR 1.20, 95% CI 1.17-1.23, p <0.001) and PC (1.15, 1.08-1.21, p <0.001) stroke. In PC stroke, treatment with IV tPA was a strong predictor of excellent outcome at 3 months (OR 5.62, 95% CI 1.06-29.9, p < 0.05). CONCLUSION: There is a potential risk for death or disability in patients with PC stroke even with low NIHSS scores. These data suggest that treatment with IV tPA should not be withheld from patients with PC stroke syndromes based on the NIHSS score.