Abstract WP4: Age and NIHSS score Predict Outcome in Patients With Mild Stroke and Proximal Large Vessel Occlusion

Background: Current guidelines recommend mechanical thrombectomy for patients with anterior circulation proximal large vessel occlusion (LVO), NIHSS≥ 6, within 6 hours from symptom onset, with a NCCT ASPECTS of 6 or higher. It remains unclear whether patients with NIHSS < 6 and LVO should also undergo mechanical thrombectomy. The benefit of intervention, associated risk and predictors of outcome in this patient population has not been studied. We sought to determine the natural history and predictors of good outcome in patients NIHSS Methods: We abstracted data from our ischemic stroke prospective database and included patients with NIHSS < 6 and presence of proximal large vessel occlusion admitted between January 1 st , 2015 and April 30 th , 2017. The outcome, 90-day mRS, was collected via a phone call at 90 days. Patients were divided into two groups: good outcome (90-day mRS 0-1) and poor outcome (90-day mRS 2-6). We compared baseline demographics, treatments, neuroimaging data (ASPECTS score), and vascular imaging findings (location of occlusion, collateral score: poor, good, and excellent) between the two groups. P-value < 0.05 was considered significant. Results: A total of 68 patients were identified; 50/68 did not undergo mechanical thrombectomy; out of which only 25/50 (50%) had a good 90-day outcome. Patients with a good outcome were younger (Mean ± SD, 69.3 ±3.2 vs 76 ± 2.2 years of age, p=0.033) and had a lower median admission NIHSS score (3 vs. 4, p=0.026).There was a trend towards good outcome with ICA and M1- MCA occlusion when compared to other locations but this was not statistically significant. Other variables also did not achieve statistical significance. Conclusion: Younger age and lower NIHSS predict good functional outcome in patients with LVO and mild deficits. Larger prospective studies are needed to verify our findings and explore the role of mechanical thrombectomy in patients who might be at risk of poor outcome.