Mechanical thrombectomy has become the standard of care for patients with stroke secondary to large vessel occlusion (LVO). While the guidelines for the acute treatment of stroke have expanded to include thrombectomy within the 6–24-hour window, within this expanded time window, 45-51% of patients have poor neurological outcomes per modified Rankin scores (mRS), with mortality rates around 15%. While a variety of factors have been identified as correlating with worse clinical outcomes following stroke, a clinically useable model for outcome prognostication has not been established. The purpose of this investigation is to identify clinical and imaging biomarkers for functional outcome following acute stroke secondary to M1/ICA occlusion during the extended time window.

Between  2018 to  2021, 276 patients underwent thrombectomy at our Comprehensive Stroke Center. Of these, 61 (33%) met inclusion criteria. Descriptive statistics were reported. We conducted Fisher’s Exact Tests for categorical variables and Wilcoxon Rank Sum test for continuous variables to determine difference between favorable (90-day mRS 0-2) and unfavorable (90-day mRS 3-6) groups.

Comparing patient populations with favorable and unfavorable outcomes, median ages were 70 and 80 respectively (p = 0.05), with similar gender distributions, site of occlusion, diabetes rates, and smoking histories. Atrial fibrillation (AFib) and hypertension (HTN) were more common among unfavorable outcome population (p = 0.01 and 0.03 respectively) as was timing from symptom onset to presentation (p = 0.01), which propagated to time to groin puncture and reperfusion (p=0.0018 and p=0.0129 respectively)

No statistical differences were present on ASPECTS score, core infarct or penumbra size, thrombolysis in cerebral infarction (TICI) scores or length of stay (LOS).

Several factors (AFib, HTN, time-to-presentation) correlated with unfavorable outcomes. Multivariate analysis is underway to optimize early prognostication and identify patients that may benefit from thrombectomy in the extended time window.