Introduction: With randomized data proving the benefit of endovascular therapy for large vessel occlusion (LVO), there is increasing interest in developing a rapid screening tool to predict LVO in acute ischemic stroke (AIS) patients in the emergency department (ED) setting.
Methods: We implemented a new LVO screening tool in our ED in March 2016. The LVO score ranged from 0-6 and included one point for each of the following individual components: level of consciousness, gaze deviation, aphasia, dysarthria, facial droop, and arm weakness. LVO was defined as an intracranial occlusion of the internal carotid artery, M1 and M2 segments of the middle cerebral artery, A1 and A2 segments of the anterior cerebral artery, P1 and P2 segments of the posterior cerebral artery, basilar artery, or vertebral arteries. We calculated c-statistics to determine the discrimination of the LVO score for presence of LVO on emergent vascular imaging and identified the optimal cut-off score with maximum sensitivity and specificity.
Results: Among 65 consecutive confirmed AIS patients between March and July 2016, 63.1% had a positive LVO screen (score > 0); 97% of the patients underwent emergent CT angiography. Eleven (16.9%) patients had an LVO in the territory of ischemic infarct, 10 of which were in the anterior circulation. The LVO score had a c-statistic of 0.77 (95%CI 0.59-0.96, p< 0.005) for predicting LVO. An optimal cut-off score > 2 was present in 19 patients (29.2%) and was associated with 72.7% sensitivity and 79.6% specificity; positive and negative predictive values were 42.1% and 93.5%, respectively.
Conclusions: In a preliminary analysis, a simple LVO screening tool had acceptable discrimination for predicting LVO in AIS patients in the ED. Further validation and refinement of the tool is necessary.