Introduction: Early revascularization improves outcomes in patients with acute stroke, and prehospital identification of patients with large vessel occlusions can result in preferential transport to centers with endovascular capability. Several stroke severity scales have been developed to assist with prehospital triage, but emergency medical services (EMS) provider training on new assessment scales presents challenges.
Hypothesis: A dichotomized Cincinnati Prehospital Stroke Scale (CPSS) with a cut-off of 2 correlates with acute stroke revascularization in a large US city.
Methods: Patients with confirmed stroke arriving via EMS between August 2012 and April 2014 at a high-volume stroke center in a large urban city with a single municipal EMS provider were identified. Demographics, prehospital CPSS, initial NIH stroke scale score (NIHSS) at hospital arrival, and type of revascularization (intravenous tissue plasminogen activator [IVtPA] or endovascular) were captured. Spearman’s rank correlation and Mann-Whitney U Test were performed after applying skewness/kurtosis tests. The Youden index was used to identify the optimal cut-off for the dichotomized CPSS. Multivariate logistic regression controlling for age, sex, and race determined the odds ratio (OR) for revascularization.
Results: A total of 144 patients were included; 51% were male, 57% were white, and 33% were black. The mean age was 68.8 years (SD 16.1). A total of 31 patients (21.5%) underwent revascularization, most often with IVtPA alone (n=30). CPSS was ≥2 in 42% of patients, and the median NIHSS in patients with CPSS <2 vs CPSS ≥2 was 2 vs 8 (p<0.0001). CPSS and NIHSS in patients presenting within 4.5 hours were strongly correlated (Spearman's rho = 0.57, p<0.0001). The optimum CPSS cut-off that predicted revascularization was 2, with a sensitivity of 0.79, specificity of 0.81, and a Youden index of 0.61. CPSS ≥2 was strongly associated with revascularization (adjusted OR 14.5, 95% CI 5.0-42.4).
Conclusions: Prehospital dichotomized CPSS with a cut-off of 2 is well correlated with acute stroke revascularization in a large US city. Further studies should investigate how the dichotomized CPSS performs in the prehospital identification of stroke patients with large vessel occlusions.