Background: There is limited evidence on the performance of emergent large-vessel occlusion (LVO) stroke screening tools when used by emergency medical services (EMS) and emergency department (ED) providers. We assessed the validity and predictive value of the vision, aphasia, neglect (VAN) assessment when completed by EMS and in the ED among suspected stroke patients.
Methods: We conducted a retrospective study of VAN performed by EMS providers and VAN inferred from the National Institutes of Health Stroke Scale performed by ED nurses at a single hospital. We calculated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of VAN by EMS and in the ED for LVO and a combined LVO and intracerebral hemorrhage (ICH) outcome.
Results: From January 2018 to June 2020, 1,547 eligible patients were identified. Sensitivity and specificity of ED VAN were similar for LVO (72% and 74%, respectively), whereas EMS VAN was more sensitive (84%) than specific (68%). PPVs were low for both EMS VAN (26%) and ED VAN (21%) to detect LVO. Due to several VAN-positive ICHs, PPVs were substantially higher for both EMS VAN (44%) and ED VAN (39%) to detect LVO or ICH. EMS and ED VAN had high NPVs (97% and 96%, respectively).
Conclusions: Among suspected stroke patients, we found modest sensitivity and specificity of VAN to detect LVO for both EMS and ED providers. Moreover, the low PPV in our study suggests a significant number of patients with non-LVO ischemic stroke or ICH could be over-triaged with VAN.
Keywords: stroke.
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