Abstract WP178: “CTA for All”: Emergency CT Angiography for All Stroke Patients Presenting Within 24 Hours of Onset Improves Outcome After Large Vessel Occlusion

Abstract

Introduction: Computed tomographic angiography (CTA) is an important initial assessment for detecting large vessel occlusion (LVO) in acute ischemic stroke (AIS) and for selecting patients for mechanical thrombectomy (MT). This study is designed to evaluate the impact of an emergency CTA protocol on outcome of AIS patients with LVO. Methods: On July 1, 2017 we implemented the policy of performing CTA at the same time as non-contrast CT (NCCT) in all AIS patients presenting within 24 hours of symptom onset regardless of baseline NIHSS. Previously emergency CTA was reserved for patients presenting within 6 hours with an NIHSS ≥6. We compared treatment processes and outcomes between AIS patients admitted 1-year before (N=396) and 1-year after (N=494) protocol implementation. Results: After protocol implementation, more patients underwent CTA (90% vs 60%, P < 0.001) and had CTA performed at the time of the initial NCCT (77% vs 34%, P <0.001). Median time from last known well (LKW) to CTA was also shorter (2.4 [interquartile range, IQR 1.2-6.0] vs 2.9 [IQR 1.5-7.6] hours, P = 0.005). More cases of LVO were detected (162 vs 93; 33% vs 25% of all AIS, P = 0.007), and more MT cases were performed (110 vs 69; 22% vs 17% of all AIS, P=0.07). Among LVO patients who presented within 6 hours of onset, median time from symptom onset to MT was shorter (209 [IQR 166-289] vs 247 [IQR 195-338] minutes, P = 0.031), and more were discharged with a favorable outcome (GOS 4-5, 54% vs 36%, P = 0.015). Symptomatic intracerebral hemorrhage (1% vs 5%, P = 0.159) and mortality (13% vs 22%, P = 0.097) were also non-significantly lower among LVO patients who presented within 6 hours of symptom onset. Conclusion: Emergency CTA for all stroke patients presenting within 24 hours regardless of baseline NIHSS improves LVO detection, increases the MT treatment population, speeds intervention, and improves outcome after LVO. The benefit primarily affects patients who present within 6 hours of symptom onset.