Abstract W MP76: Diagnostic Accuracy and Characteristics of Missed Ischemic Strokes in the Emergency Department

Objectives: The failure to recognize an acute stroke in the ED represents a missed opportunity for potential thrombolytic therapy and for prompt treatment for secondary prevention. The aim of this study was to examine the diagnostic accuracy of acute ischemic strokes at a large academic center and to identify common characteristics of these missed strokes. Methods: A retrospective review was performed on a random sample of patients >18 years old with a discharge diagnosis of ischemic stroke in 2013. All acute strokes were confirmed on CT or MRI. A stroke was “missed” if practitioners in the ED did not initially consider stroke in the differential, or the diagnosis was delayed causing the patient to miss the therapeutic window for thrombolytic therapy. Results: Two hundred ischemic stroke patients were included in the study. The mean patient age was 72 years, and the mean initial NIHSS was 7. There were 36 “missed” strokes (18%) in this population. Of the strokes that were initially misdiagnosed, 20 of 36 (56%) presented in the time window for thrombolytic therapy and potentially could have received intervention. Posterior circulation strokes were more likely to be missed overall (20/58 posterior, 34%, vs 16/142 anterior, 11%, p < 0.001). Seventy-six percent of patients with posterior stroke had stroke in the original differential compared with 96% in those with anterior circulation stroke (p < 0.001). Symptoms independently associated with posterior circulation strokes included nausea/vomiting (OR=6.9, 95% CI: 2.0-23), headache (OR=6.4, 95% CI: 1.5-27) and difficulty walking (OR=3.5, 95% CI: 1.3-9.5). Anterior circulation patients more commonly presented with focal weakness (OR=0.11, 95% CI: 0.05-0.25) and aphasia (OR=0.17, 95% CI: 0.06-0.45). Conclusions: Despite having a certified stroke program in a large academic medical center, 18% of acute ischemic strokes were missed in the ED. Posterior circulation strokes were 3 times more likely than anterior strokes to be missed. Posterior stroke patients were more likely to present with nausea/vomiting, headache and difficulty walking, and these symptoms should serve as triggers to consider ischemic stroke in the ED.