Availability & Applicability of the National Institute of Health Stroke Scale at Time of Imaging Interpretation for Code Stroke in the Community Hospital Setting.

Abstract

Objective: Stroke is a leading cause of global disability and mortality, a burden projected to grow as populations age worldwide. Early recognition and our ever-advancing interventions can substantially change outcomes and final costs. This has warranted adapting strategies that maximize sensitivity, including a lower threshold for code stroke imaging. This growing demand requires matching resources, an issue that is particularly noticeable in community hospital settings. The National Institutes of Health Stroke Scale (NIHSS) is a well-established quantitative tool for guiding clinical management. This study aimed to assess the availability and applicability of the NIHSS at the time of imaging for code stroke evaluations in a community hospital setting and in comparison to the previous studies conducted in tertiary academic centers. Materials and methods: We performed a retrospective analysis of all code stroke activations at a community Level 1 stroke center from October 2021 to September 2023, when institutional benchmarks were last adapted. All patients underwent non-contrast head CT, CT angiography of the head and neck, and subsequent brain MRI. Data collected included NIHSS documentation status, door-to-CT and door-to-NIHSS times, imaging positivity, final neurological diagnosis, and therapeutic interventions. Statistical analysis included descriptive statistics, t-tests, and receiver operating characteristic (ROC) analysis using NIHSS to predict positive strokes. Results: A total of 291 patients were included (151 women, 140 men). NIHSS documentation prior to imaging was available in 61.2% of cases. Median door-to-CT time was 12 minutes, while median door-to-NIHSS time was 29 minutes. Imaging was positive for acute stroke in 33.6% of cases. Patients with NIHSS documented prior to imaging had a higher stroke positivity rate (36.5% vs 28.0%; odds ratio [OR] 1.45 (95% CI 0.86-2.42). The mean NIHSS among all patients was 6.3, and higher scores correlated with positive imaging (mean 9.1 vs 3.7). ROC analysis for NIHSS predicting imaging positivity yielded an AUC of 0.69. Notably, eight patients (2.7% of all patients) had an NIHSS of 0 but demonstrated acute infarcts on imaging. Conclusion: Our findings demonstrate that NIHSS documentation often lags behind imaging in a community setting, yet its availability can provide useful prognostic information. Higher NIHSS scores correlate with a higher number of positive strokes by imaging, yet, strokes may be seen even with an NIHSS score of 0. These findings emphasize maintaining a low threshold for imaging and the importance of prompt NIHSS documentation, especially in community stroke centers increasingly relying on tele-neurology.