Intravenous Thrombolysis 4.5–9 Hours After Stroke Onset: A Cohort Study from the TRISP Collaboration.

Objective: To investigate the safety and effectiveness of intravenous thrombolysis (IVT) >4.5–9 hours after stroke onset, and the relevance of advanced neuroimaging for patient selection. Methods: Prospective multicenter cohort study from the ThRombolysis in Ischemic Stroke Patients (TRISP) collaboration. Outcomes were symptomatic intracranial hemorrhage, poor 3‐month functional outcome (modified Rankin scale 3–6) and mortality. We compared: (i) IVT >4.5–9 hours versus 0–4.5 hours after stroke onset and (ii) within the >4.5–9 hours group baseline advanced neuroimaging (computed tomography perfusion, magnetic resonance perfusion or magnetic resonance diffusion‐weighted imaging fluid‐attenuated inversion recovery) versus non‐advanced neuroimaging. Results: Of 15,827 patients, 663 (4.2%) received IVT >4.5–9 hours and 15,164 (95.8%) within 4.5 hours after stroke onset. The main baseline characteristics were evenly distributed between both groups. Time of stroke onset was known in 74.9% of patients treated between >4.5 and 9 hours. Using propensity score weighted binary logistic regression analysis (onset‐to‐treatment time >4.5–9 hours vs onset‐to‐treatment time 0–4.5 hours), the probability of symptomatic intracranial hemorrhage (ORadjusted 0.80, 95% CI 0.53–1.17), poor functional outcome (ORadjusted 1.01, 95% CI 0.83–1.22), and mortality (ORadjusted 0.80, 95% CI 0.61–1.04) did not differ significantly between both groups. In patients treated between >4.5 and 9 hours, the use of advanced neuroimaging was associated with a 50% lower mortality compared with non‐advanced imaging only (9.9% vs 19.7%; ORadjusted 0.51, 95% CI 0.33–0.79). Interpretation: This study showed no evidence in difference of symptomatic intracranial hemorrhage, poor outcome, and mortality in selected stroke patients treated with IVT between >4.5 and 9 hours after stroke onset compared with those treated within 4.5 hours. Advanced neuroimaging for patient selection was associated with lower mortality. ANN NEUROL 2023;94:309–320 [ABSTRACT FROM AUTHOR]