Mechanical Thrombectomy for Large Vessel Occlusion in Patients Presenting in Late Time Window

Background and Purpose— We sought to evaluate safety and efficacy of mechanical thrombectomy in patients
with anterior circulation large vessel occlusion strokes presented after 6 hours of last known well and selected based
on Diffusion Weighted Imaging (DWI)-Alberta Stroke Program Early Computed Tomography Score (ASPECTS) on
Magnetic Resonance Image (MRI).
Methods— Consecutive patients presented with large vessel occlusion strokes were enrolled from January 2019-Au
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gust 2019 in two-stroke centers if they had anterior circulation ischemic stroke due to intracranial internal carotid
artery (ICA) or proximal middle cerebral artery (MCA) occlusion and had a baseline DWI-ASPECTS >5. Patients
underwent mechanical thrombectomy plus best medical management or best medical management alone depending
upon the hospital of presentation. The primary outcome was the shift in the degree of disability at 90-day as measured
by the modified Rankin scale (mRS). Secondary outcome was functional independence at 90-day (mRS 0-2). Safety
measures were the rates of symptomatic intracranial hemorrhage (sICH) and 90-day mortality
.

Results— Fifty-seven patients were eligible for the analysis. Demographics, and baseline clinical characteristics
were similar between the patients who underwent mechanical thrombectomy (n=32) and control groups (n=25).
Mechanical thrombectomy was associated with a favorable shift in the overall distribution of 90-day mRS (P<0.001,
adjusted odds ratio; 7.985, 95% cofidence interval (CI) [2.759-25.031], p<0.001). Similarly, patients who underwent
mechanical thrombectomy had higher rates of functional independence (56.3% vs. 12%, p=0.001, adjusted odds
ratio; 16.760, 95% CI [2.822-99.548], p=0.002) at 90 days. The rates of sICH and 90-day mortality were similar
between the two groups.
Conclusions— We found that patients presenting after 6 hours of last well-known normal benefit from mechanical
thrombectomy when selected based on Diffusion Weighted Imaging-ASPECTS.