Abstract Number: Esoc2026a786 Outcomes of Extended Window Thrombolysis: A Real-World Study

Abstract Background and aims Intravenous thrombolysis (IV tPA) is standard treatment for acute ischemic stroke, typically restricted to a 4.5-hour window. Expanding the window to 4.5-9 hours, guided by imaging demonstrating favourable perfusion-to-core mismatch, can improve outcomes. This project reviewed the characteristics and outcomes of patients receiving IV tPA in this extended window at the National Hospital of Neurology and Neurosurgery (NHNN). Methods This single-centre, observational study retrospectively analysed electronic health records for patients admitted to the Emergency Stroke Unit at the NHNN between 01/04/2023 - 01/04/2024. Patients met local criteria for the extended window lysis. Results Of 2368 stroke admissions, 19 patients received IV tPA in the extended window. The mean age was 68 ±15 years, and 57.9% were male. The median NIHSS on arrival was 8 and the median door-to-needle time was 69 minutes (min: 30 – max: 181), with delays primarily attributed to assessing DOAC effectiveness. Median core volume was 6mL, and median penumbra volume was 50.5mL, confirming significant tissue at risk (median mismatch volume: 35.5mL). The median NIHSS at 24 hours was 4. Symptomatic ICH occurred in 1 patient, with parenchymal haematoma in 2. Death occurred in one patient. Median mRS on discharge was 2 (min: 0 – max: 6). Conclusions Treatment in the extended thrombolysis window for carefully selected patients is feasible and appears safe, demonstrating a favourable clinical response with a median NIHSS improvement of 4 points at 24 hours and a low rate of symptomatic ICH. Delays related to assessing anticoagulation remain a key area for improvement. Conflict of interest Claudia Zeicu: nothing do disclose; David Turner: nothing to disclose