Early Neurologic Improvement Based on the National Institutes of Health Stroke Scale Score Predicts Favorable Outcome within 30 Minutes after Undergoing Intravenous Recombinant Tissue Plasminogen Activator Therapy

Abstract

The aim of the present study was to evaluate whether early neurologic improvement (within 30 minutes), as measured using the National Institutes of Health Stroke Scale (NIHSS) score, predicts favorable outcome at 90 days. Consecutive acute ischemic stroke patients treated with intravenous recombinant tissue plasminogen activator (i.v. rt-PA) within 3 hours poststroke between March 2006 and September 2011 were analyzed retrospectively. The association between early neurologic improvement based on the NIHSS score (an improvement of ≥3 points at 15 minutes and ≥5 points at 30 minutes) and favorable outcome at 90 days was examined. A favorable outcome was defined as a modified Rankin scale (mRS) score of 0 or 1 at 90 days after treatment. On examination of the time course of the NIHSS score in patients with an improvement of ≥8 points or a score of 0 on the NIHSS after 24 hours, the NIHSS score improved significantly from 15 minutes after i.v. rt-PA treatment (P = .042) and at 30 minutes (P = .014). On logistic regression analysis, an improvement of ≥3 NIHSS points at 15 minutes (odds ratio [OR] 6.78; 95% confidence interval [CI] 1.72-26.70; P = .006) and an improvement of ≥5 NIHSS points at 30 minutes (OR 4.83; 95% CI 1.05-22.28; P = .043) were associated with a favorable outcome. An improvement of at least 3 points in the NIHSS score at 15 minutes or of at least 5 points at 30 minutes appears to be a predictor of favorable outcome and helps to identify patients who will not respond to rt-PA therapy.