NIHSS Subitems Enhance LVO Prediction in Minor Stroke Patients

Introduction While stroke is a leading cause of disability and mortality, recent advancements in neurovascular interventions to treat large vessel occlusions (LVO) are very promising. A focal point of these advancements is determining if there are appropriate criteria for the expansion of treatment beyond the initial inclusion criteria to low NIHSS or more distal occlusions. While these scenarios are being evaluated in clinical trials, the utilization of acute vessel imaging has grown dramatically. Determining how to best identify the patients for acute vessel imaging is of high importance. The purpose of this study is to evaluate the utilization of low NIHSS subitems to help determine which patients with a low NIHSS are most likely to have a LVO. Methods Acute stroke consultations seen in the emergency department with CT angiogram ± perfusion performed and admitting diagnosis of stroke or TIA in 227 facilities (27 states) from July 1, 2021 to December 31, 2021 were extracted from the TeleCare by TeleSpecialists TM database. The encounters were reviewed for LVO detected, demographics, stroke risk factors, pre‐morbid modified Rankin Score (p‐mRS), location of LVO, treatment with thrombolytics, median door to needle (DTN) times for thrombolytics candidates, last known normal (LKN) to arrival median time, NIHSS total score, and NIHSS score with individual subitems. Baseline characteristics and stroke metrics will be compared between LVO and non‐LVO patients. The odds ratio (OR) of having a LVO with points in each individual NIHSS subitem as well as an adjusted odds ratio for age and gender were calculated for the total population and the NIHSS <6 patient population. Results There were 9,719 patients with 1,383 having a LVO and 8,336 non‐LVO patients. The two groups had significant differences in median age, median NIHSS score, history of hypertension, atrial fibrillation and coronary artery disease. There were significantly shorter DTN times (non‐LVO 41 minutes vs LVO 38 minutes, p<0.0001), LKN to arrival times (non‐LVO 195 minutes vs LVO 170 minutes, P=0.0052), and higher thrombolytic treatment rate (non‐LVO 14.5% vs LVO 30.59%, p<0.0001) in the LVO group. Orientation questions ( adjusted OR of 1.40; 95% CI 1.15‐1.69), following commands (adjusted OR of 2.39; 95% CI 1.24‐4.16), visual fields (adjusted OR of 1.69; 95% CI 1.34‐2.09), Facial Weakness (adjusted OR of 1.55; 95% CI 1.30‐1.84), Left arm motor (adjusted OR of 1.31; 95% CI 1.02‐1.64), sensation (adjusted OR of 0.63; 95% CI 0.47‐0.84), aphasia (adjusted OR of 1.93; 95% CI 1.64‐2.26), dysarthria (adjusted OR of 1.60; 95% CI 1.25‐2.03) and extinction (adjusted OR of 4.93; 95% CI 2.55‐8.96). Conclusions The goal of this study was to evaluate for individual NIHSS subitems that could predict LVO during the initial stroke assessment. Nine of the fifteen variables were found to have a significant difference in the LVO population. This demonstrates the large spectrum of presentations in the low NIHSS population making it challenging to use individual subitems as a prediction model for LVO, supporting the utilization of CTA for all acute stroke patients.