Patients with Low National Institutes of Health Stroke Scale Scores Have Longer Door-to-Needle Times: Analysis of a Telestroke Network

Abstract

The benefits of intravenous tissue-type plasminogen activator (IV-tPA) in acute ischemic stroke (AIS) are time dependent. Because emergency rooms quickly initiate a stroke alert with more severe symptoms, we hypothesized that patients with lower National Institutes of Health Stroke Scale (NIHSS) scores, indicating a less severe stroke, would have longer door-to-needle (DTN) times compared to patients with higher NIHSS scores. Data obtained from the 19-hospital Providence Stroke Registry were used to identify AIS patients who received IV-tPA within 4.5 hours of last-known-well. NIHSS scores were obtained prior to tPA administration at the time of emergency department presentation and categorized as low-NIHSS (score = 0-5) or high-NIHSS (score = 6-42) strokes. Median DTN times were collected for both groups as the primary outcome variable. Linear mixed-effects regression models were used to assess the effect of NIHSS scores on DTN and its 2 components: door-to-CT (DCT) and CT-to-needle (CTN) times. We identified 692 AIS patients who received IV-tPA within 4.5 hours of last-known-well, with 198 patients presenting with low-NIHSS strokes and 494 patients with high-NIHSS strokes. In multivariable analysis, median DTN time was estimated to be 18% higher for low-NIHSS strokes than high-NIHSS strokes after adjusting for covariates (P < .001). Median DCT times were also higher for low-NIHSS (19 minutes) compared to high-NIHSS (11 minutes) strokes after adjusting for covariates (P < .001), whereas CTN times were unchanged (P = .055). In AIS patients receiving IV-tPA in a telestroke network, lower NIHSS scores were associated with longer DTN and DCT times.