Test characteristics of a 5‐element cortical screen for identifying anterior circulation large vessel occlusion ischemic strokes

Abstract

Abstract Objective Stroke severity screens typically include cortical signs, such as field cut, aphasia, neglect, gaze preference, and dense hemiparesis (FANG‐D). The accuracy and reliability of these signs, when assessed by emergency physicians, to identify patients with anterior circulation large vessel occlusion (ACLVO) acute ischemic stroke (AIS) is unknown. We hypothesized that the FANG‐D screen applied by emergency physicians would be sensitive and reliable for identifying ACLVO AIS. Methods We conducted a prospective cohort study enrolling consecutive patients with suspected AIS presenting within 4.5 hours of last known well to the emergency department (ED). Emergency physicians performed the FANG‐D screen prior to, and blinded to the results of, imaging. The imaging standard was defined as a non‐contrast computed tomography (CT) for identifying hemorrhage and CT angiography for identifying large vessel occlusion. ACLVO was defined as an occlusion of the internal carotid artery, the middle cerebral artery, or its first branch. A convenience sample of patients had a duplicate FANG‐D screen performed by a second emergency physician to assess interobserver agreement. Results We performed 608 FANG‐D assessments on 491 patients presenting to the ED, of whom 64 (10%) had an ACLVO. FANG‐D had a sensitivity of 91% (confidence interval [CI] = 81%–96%) and a specificity of 35% (CI = 31%–39%) for identifying ACLVO. Interobserver agreement was tested on 133 patients and was found to be substantial, with a Fleiss’ kappa of 0.77 (CI = 0.64–0.88). Conclusions The FANG‐D screen is a sensitive test for identifying ACLVO when performed by emergency physicians and demonstrates substantial interrater reliability.

Keywords

• acute stroke
• screening
• diagnostic imaging
• thrombectomy
• neurology
• emergency medicine