233 The Impact of a Large Vessel Screening Tool to Reduce Delays in Evaluation and Intervention in Emergency Department Stroke Patients

Abstract

The DAWN and DEFUSE-3 trials established endovascular thrombectomy (ET) as standard care for select patients with ischemic stroke due to large vessel occlusion (LVO) up to 24 hours from last known well (LKW). In 2018, our institution, a 600-bed Level-1 teaching hospital and Comprehensive Stroke Center with 62,000 emergency department (ED) visits per year, expanded stroke alert activation to include all patients presenting with stroke symptoms within 24 hours of LKW. However, while our volume of stroke alerts increased substantially with this stroke window expansion, the specificity of our alert process declined as many alerted patients were not eligible for neurovascular intervention. In January 2019, with the goal of improving the specificity of our stroke alert and reduce delays in treatment, we revised our stroke alert criteria to include an LVO screening tool such that patients with > 6 hours of stroke symptoms who did not have exam findings consistent with an underlying LVO did not trigger an emergent stroke alert. The vision, aphasia, and neglect (VAN) is a screening tool designed to rapidly assess for possible LVO. In 2019, we trained all emergency physicians and nurses to assess all stroke patients on arrival to the ED using the VAN screening tool. Patients with a LKW of < 6 hours or who had > 6 hours since LKW, but were VAN positive triggered a stroke alert within our facility. We then retrospectively reviewed ED stroke alert data from 2018 after we extended our stroke alert window and 2019 when we revised our stroke protocol to include the VAN tool. We compared process metrics pre- and post- intervention with our new protocol using the VAN tool. We report mean times (min) with 95% confidence interval (CI) and perform comparisons using Student’s t-tests. In 2018, our ED called 596 stroke alerts; 170 patients (30.2%) were ultimately diagnosed with ischemic stroke. January through March of 2019, 106 alerts were activated, of which 37 were diagnosed with an ischemic stroke (35%) following the implementation of our new VAN protocol. In 2018, 52 patients (8.7%) received tissue plasminogen activator (tPA) and 37 patients (6.4%) underwent ET, compared to 14 patients (13.2%) receiving tPA and 2 patients (1.9 %) undergoing ET in 2019. Mean door to alert time decreased from 18 min [16.5, 19.4] in 2018 to 13 min [6.26,11.74] in 2019 (p = 0.024). Mean treatment times decreased from door to tPA of 57.1 min [48.5, 66.1] in 2018 to 53.3. min [50.27, 56.34] in 2019 (p= 0.15), and door to groin puncture of 93.6 min [74.2, 113] in 2018 to 64 min [36.56, 91.44] in 2019 ( p> .05). Utilizing the VAN screening tool as part of our stroke alert protocol improved the overall specificity of our stroke alert. Additionally, we observed decreased door to alert, door to tPA, and door to thrombectomy times, following the implementation of our new protocol. The LVO screening tool does not appear to dramatically reduce stroke resource utilization within the ED; however, the teaching of this screening tool likely improved provider education to detect stroke symptoms and reduced delays in assessment and treatment.