Abstract W P47: Recanalization After IV TPA Alone Among Acute Ischemic Stroke Patients Treated With Combined IV-Endovascular Recanalization: Impact of Arterial Occlusion Site

Background: Combined IV TPA and catheter-based reperfusion is an emerging treatment strategy for acute ischemic stroke. Both patient care and clinical trial design would be enhanced by delineation of which patients rapidly respond to IV TPA alone, before endovascular therapy can be initiated. Methods: In a prospectively maintained registry of patients treated under a general policy of combined IV TPA and endovascular therapy, we analyzed subjects with MRA/CTA-confirmed anterior circulation occlusions prior to IV TPA start. Results: Among 118 patients meeting study entry criteria, age was mean 71.5 (SD 14.5), 53.0% were female, and baseline NIHSS was 14.4 (SD 7.1). Confirmed sites of occlusion prior to IV TPA were internal cerebral artery (ICA) in 22.9%, M1 segment of middle cerebral artery (MCA) in 50.0%, and M2-3 in 27.1%. Among patients undergoing catheter cerebral angiography, median time from start of IV TPA to diagnostic catheter angiogram was 75 mins (IQR 50-113). A total of 48 (40.7%) patients achieved partial or complete recanalization (AOL 2-3) of the initial target artery with IV TPA alone (partial in 22 (18.6%) and complete in 26 (22.2%)); an additional 44 (37.3%) achieved partial or complete recanalization after endovascular therapy. Recanalization rates after IV TPA alone varied by target occlusion site: ICA - 22.2%, M1 - 40.7%, and M2-3 - 56.2%. In multivariate logistic regression analysis, independent predictors of recanalization with IV TPA alone were: M2-3 clot location, OR 3.04 (95% CI 1.20-7.73, p=0.019) and TOAST etiology large-artery atherosclerosis, OR 0.14 (CI 0.04-0.50, p = 0.003). Good outcome (mRS ≤ 3) rates at 3 months were 76.6% among recanalizers with IV TPA alone and 47.5% among recanalizers after both IV TPA and catheter therapy. Conclusions: When combined IV-endovascular treatment is pursued, recanalization with IV TPA alone occurs in 4 out of 10 patients before catheter therapy is started, is more common with more distal clot location, and is associated with a high rate of excellent clinical outcomes.