Large Vessel Occlusion Score: A Screening Tool to Detect Large Vessel Occlusion in the Acute Stroke Setting

Background: The results of recent trials of mechanical thrombectomy for acute ischemic stroke have increased the demand for identification of patients with large vessel occlusion (LVO) at the primary stroke center, where a prompt detection may expedite transfer to a comprehensive stroke center for endovascular treatment. However, in developing countries, a noncontrast computed tomography (NCCT) may be the only neuroimaging modality available at the primary stroke center scenario, what calls for a screening strategy accurate enough to avoid unnecessary transfers of noneligible patients for endovascular therapy. Algorithms based on National Institute of Health Stroke Scale (NIHSS) and NCCT findings can be used to screen for LVO in patients with anterior circulation stroke (ACS). Objective: To test the accuracy of a score based on NIHSS and NCCT to detect LVO in patients with ACS. Methods: We evaluated 178 patients from a prospective stroke registry of patients admitted to an academic tertiary emergency unit. NIHSS and vessel attenuation values of the middle cerebral artery on NCCT absolute vessel attenuation (VA) were collected by 2 investigators that were blind to CT angiography (CTA) findings. We used receiver operating characteristics curve analysis and C-statistics to predict LVO on CTA. Results: NIHSS and vessel attenuation were highly associated with LVO with an area under the curve (AUC) of .86 and .77. The LVO score, built by logistic regression coefficients of the NIHSS and VA, showed the highest accuracy for the presence of LVO on CTA (AUC of .91). Conclusion: The LVO score may be a useful screening approach to identify LVO in patients with ACS.