Abstract P499: The Effect of Small Vessel Disease Burden on Core/Penumbra Mismatch and Outcomes in Extended Window Thrombectomy

Abstract

Objective: Recent studies have shown the benefit of revascularization in select patients with extended window large vessel occlusion (EWLVO). We sought to assess the effect of cerebral small vessel disease (CSVD) burden on eligibility for intervention with mechanical thrombectomy (MT) and functional outcomes in patients with EWLVO. Methods: We conducted a retrospective single-center study of 135 patients with anterior circulation LVO who presented in the extended time window, 6 to 24 hours from LKW, between August 2018 and March 2020. All patients underwent perfusion imaging at initial presentation and those with target ischemic core to penumbra mismatch profiles, as defined by DAWN/DEFUSE3 criteria, were treated with MT. Included patients were evaluated for CSVD burden using T2-FLAIR MRI. The Fazekas scale (0-3) was used to quantify the amount of white matter T2 hyperintense lesions in both the periventricular (PVWM) and deep white matter (DWM). Patients’ functional outcomes were assessed at 90 days using the mRS. Multivariate ordinal logistic regression models were used and adjusted for age, gender, thrombus location and LKW to perfusion imaging time. Patient information was collected from the Houston Methodist Hospital Outcomes Based Prospective Endpoints in Stroke (HOPES) registry. Results: Of the 135 patients, 111 met imaging inclusion criteria for revascularization with MT for EWLVO. MT was deferred in 44 of these patients due to other clinical exclusions or patient refusal. Patients ineligible for MT were approximately 13 times more likely to have a higher PVWM Fazekas grade (OR =13.53, 95% CI. [2.94 - 62.39], p=0.001) and 17 times more likely to have a higher DWM Fazekas grade (OR =17.54, 95% CI. [4.20 - 73.17], p<0.001), when compared to patients who were eligible for MT. Patients who did not meet criteria for MT were nearly 7 times more likely to have poor functional outcomes at 90 days (OR =6.85, 95% CI. [2.09 - 22.44], p=0.001). Conclusion: Based on our analytical cohort of EWLVO patients, those with severe CSVD burden were more likely to be excluded from MT and had worse functional outcomes. Poor cerebrovascular reserve and diminished collateral flow leading to rapid infarct progression in patients with greater CSVD burden may be a potential explanation.