Abstract TP75: Safety and Outcome of Thrombolysis in Acute Stroke with Prolonged Onset-to-Treatment Times and Low National Institute of Health Stroke Scale Scores. Report on Experience in China, First 1000 Patients of 3300 Treated

Introduction: Stroke in China is the leading cause of death. We report on a collaboration between a large metropolitan hospital in China, Tianjin Huanhu Hospital, and Inova Fairfax and Inova Alexandria Stroke Programs presenting data on the first 1000 (of more than 3300 treated since 2012) patients treated with IV-rtPA. The safety and efficacy of treatment with rtPA between 4.5-6 hours after onset is unclear. Similarly there is little data on outcome of patients treated with rtPA with normal or low NIHSS. Methods: Patients were treated with thrombolysis between late 2012 and fall of 2014. Patients had MRI scans at 24 hours. Patients had NIHSS scores before and after treatment, and modified Rankin Scores (mRS) at 90 days after treatment. Results: See Chart. Conclusions: 1) IV-rtPA can be given safely between 4.5-6 hours without significant risk of sICH and worsening outcomes. 2) Higher NIHSS before thrombolysis was correlated with poorer outcomes. 3) There was no significant correlation between onset to treatment time up to 6 hours and outcome. 4) Outcome was excellent (mRS 0-1) in 72% treated 0-3 hours, 74% 3-4.5 hours and remarkably 85% 4.5-6 hours. The data set includes many patients who were asymptomatic or nearly so prior to treatment. This will need to be more fully evaluated in the remainder (2300) of this cohort of more than 3300 treated patients. Comment: This cohort represents one of the largest series of acute stroke patients treated with IV-rtPA u003e 4.5 hours after onset. It also reveals outcome of treatment in patients with low NIHSS treated at various intervals after last know well.