Abstract WP4: Intravenous Thrombolysis And Outcomes In Patients With Large-vessel Stroke Directly Admitted Or Transferred To A Thrombectomy-capable Center

Objective: To assess whether the effect of intravenous thrombolysis in patients with large-vessel occlusion differed between patients directly admitted to thrombectomy-capable centers and patients transferred from local stroke centers without thrombectomy capabilities.

Methods: We included 3206 patients with an acute ischemic large-vessel stroke with first imaging within 7 hours after onset that were directly admitted to thrombectomy-capable centers and treated with thrombectomy, or transferred from local stroke centers for thrombectomy evaluation, between 2017 and 2021 in Catalonia, Spain. Primary outcome was the degree of disability at 90 days, as evaluated by the shift analysis on the mRs score. Secondary outcomes included mortality at 90 days and the rate of parenchymal hemorrhage and successful reperfusion. Inverse-probability weighting clustered at the type of stroke center was used to estimate the effects.

Results: The analysis included 2268 patients (975[49%] treated with thrombolysis) directly admitted to thrombectomy-capable centers and 938 patients (580[66%] treated with thrombolysis and 616[67%] treated with thrombectomy) transferred from local stroke centers (mean age 72±13 years, median NIHSS score 17[IQR 12-21], 1363 female[48%]). Patients treated with intravenous thrombolysis were younger, had shorter time from onset to first image acquisition, and higher rates of wake-up stroke, atrial fibrillation and anticoagulation intake. The effect of intravenous thrombolysis on the primary outcome was similar in patients directly admitted to thrombectomy-capable centers (acOR 1.50, 95% CI 1.24-1.81) and patients transferred from local stroke centers (acOR 1.44, 95% CI 1.04 to 2.01)(p interaction =0.68). Patients treated with intravenous thrombolysis had lower mortality rate, higher rate of parenchymal hematoma and similar rate of successful reperfusion, with no difference according to type of center (p interaction >0.1).

Conclusion: Administration of intravenous thrombolysis in patients with a large-vessel stroke with intention to thrombectomy was associated with higher odds of good functional outcome and higher rates of parenchymal hematoma, independently of the type of stroke center were it was administered.