We retrospectively reviewed AIS patients admitted between 2009 and 2017 to a large healthcare system in the northeastern United States that were enrolled in a system-wide exome sequencing project. Patients with occlusions of the internal carotid artery, or M1 or M2 segments of the middle cerebral artery were randomly split into 2/3 derivation and 1/3 validation cohorts for development of an anterior circulation LVO prediction model and score, which was further curtailed for a potential prehospital setting.

1,654 AIS were reviewed, including 248 (15%) with anterior circulation LVO AIS. In the derivation cohort, National Institute of Health Stroke Score Scale (NIHSS) score on admission, current smoking status, type 2 diabetes mellitus, extracranial carotid, and intracranial atherosclerotic stenosis were significantly associated with anterior circulation LVO stroke. The prehospital score was curtailed to admission NIHSS, current smoking status, and type 2 diabetes mellitus. The area under the curve for the prediction model, prehospital score, and admission NIHSS alone were 0.796, 0.757, and 0.725 for the derivation cohort, and 0.770, 0.689, and 0.665 for the validation cohort, respectively.

Previously reported LVO stroke prediction scores focus on elements of the neurologic exam. In addition to the NIHSS, smoking, type 2 diabetes mellitus, extracranial carotid, and intracranial atherosclerotic stenosis were associated with anterior circulation LVO AIS in this study. Smoking and diabetes mellitus history can be readily obtained and represent important elements of the prehospital score supplementing NIHSS.