The impact of time to reperfusion on recanalization rates and outcome after mechanical thrombectomy: A single center experience

Background: Timely and effective recanalization to salvage the penumbra is the main determinant of outcome in acute ischemic strokes. Randomized controlled trials on late window mechanical thrombectomy (MT) have proved its safety and efficacy upto 24 h after stroke onset. We looked at the impact of time to reperfusion on vessel recanalization rates and short-term outcome in patients undergoing MT for large vessel occlusion. Methods: The clinical, imaging, and outcome of all patients undergoing MT upto 24 h from last seen normal was extracted from a prospectively maintained ischemic stroke database from January 2012 till September 2019. Results: There were 145 patients with a mean (SD) age of 58.2 (±14) years. Of them, 28 had wake up/unknown time of onset stroke and 9 presented beyond >360 min. There were 23 vertebrobasilar strokes. Median National Institute of Health Stroke scale score (NIHSS) at admission was 16.4 (Inter quartile range (IQR) 12–21). CT-Alberta Stroke program early CT score (CT-ASPECTS) was excellent (8–10) in 39 (31.6%) and fair (5–7) in 77 (63.6%) patients in anterior circulation strokes. About 25% underwent bridging therapy. Recanalization rates did not differ between those presenting early (<6 h) versus wake up strokes and late presenting patients (81.79% vs 71.9%). Symptomatic Intracerebral hemorrhage (ICH) occurred in 5%. At 3 months, excellent outcome (modified rankin scale <2) was observed in 28.9%. While Admission NIHSS remained strong predictor of poor outcome at 3 months, delay in presentation did not impact MT outcome (37.5% vs 45.79% and P = 0.460). Conclusions: The recanalization rates were similar in patients irrespective of the time to reperfusion from stroke onset. The functional outcome was not inferior in late presenters selected by advanced imaging.