Stroke vision, aphasia, neglect (VAN) assessment-a novel emergent large vessel occlusion screening tool: pilot study and comparison with current clinical severity indices

Abstract

Background: Identification of emergent large vessel occlusion (ELVO) stroke has become increasingly important with the recent publications of favorable acute stroke thrombectomy trials. Multiple screening tools exist but the length of the examination and the false positive rate range from good to adequate. A screening tool was designed and tested in the emergency department using nurse responders without a scoring system.

Methods: The vision, aphasia, and neglect (VAN) screening tool was designed to quickly assess functional neurovascular anatomy. While objective, there is no need to calculate or score with VAN. After training participating nurses to use it, VAN was used as an ELVO screen for all stroke patients on arrival to our emergency room before physician evaluation and CT scan.

Results: There were 62 consecutive code stroke activations during the pilot study. 19 (31%) of the patients were VAN positive and 24 (39%) had a National Institutes of Health Stroke Scale (NIHSS) score of ≥6. All 14 patients with ELVO were either VAN positive or assigned a NIHSS score ≥6. While both clinical severity thresholds had 100% sensitivity, VAN was more specific (90% vs 74% for NIHSS ≥6). Similarly, while VAN and NIHSS ≥6 had 100% negative predictive value, VAN had a 74% positive predictive value while NIHSS ≥6 had only a 58% positive predictive value.

Conclusions: The VAN screening tool accurately identified ELVO patients and outperformed a NIHSS ≥6 severity threshold and may best allow clinical teams to expedite care and mobilize resources for ELVO patients. A larger study to both validate this screening tool and compare with others is warranted.

Keywords: Economics; Stroke; Thrombectomy.

Figure 1

Stroke process before and after the VAN protocol was initiated. CTA, CT angiography; tPa, tissue plasminogen activator; VAN, vision, aphasia, neglect.

Figure 2

Large vessel occlusion screening tools—brain view. 3I-SS, 3 item stroke scale; CPSSS, Cincinnati Prehospital Stroke Severity Scale; LAMS, Los Angeles Motor Scale; LEGS, legs, eyes, gaze, speech (Texas Stroke Intervention Prehospital Stroke Severity Scale); RACE, Rapid Arterial oCclusion Evaluation Scale; VAN, vision, aphasia, neglect.