Abstract TMP14: Contemporary Use of IV Alteplase in Acute Ischemic Stroke Beyond 4.5 Hours of Stroke Onset in Clinical Practice is Rare

Abstract

Introduction: Two RCTs conducted from 2010-2018 showed benefit in ischemic stroke (IS) of IV tPA >4.5 h from last known well (LKW) using advanced imaging selection. Many subjects were wakeup strokes treated < 4.5 h of symptom discovery (SxD). We assessed the frequency of IV tPA > 4.5 h in the national GWTG-Stroke clinical registry during the same period as the RCTs were performed. Methods: We analyzed all IS hospitalizations between 1/1/09 - 10/1/18 at fully participating GWTG-Stroke sites to identify 219,565 patients at 1919 sites who received IV tPA (no thrombectomy) and had valid LKW, SxD and treatment times recorded. Table shows significant covariates (standardized differences >10%) Results: Treatment beyond 4.5 h from LKW was rare, occurring in 2.19% (n=4798) of all tPA cases, and 50% of those treated were still within 4.5 h from SxD. The distribution of time to treatment in minutes was similar when stroke onset was defined by LKW compared to SxD (median (IQR) 134 (100-174) vs. 125 (94-163)) (Fig). The use of IV tPA at >4.5 h from LKW as a proportion of all tPA cases treated varied substantially across sites (median (IQR) 1.7% (0-3.1%)) but fewer than ~10% of sites had more than 5% of their tPA use occurring beyond 4.5 h. Compared to < 4.5 h, patients treated >4.5 h differed in age, AF, arrival mode/time, stroke severity and hospital region (Table). Conclusions: During the past decade and prior to published RCT evidence that extended window IV tPA was effective, US sites in GWTG-Stroke rarely treated patients beyond the guideline-approved window of 4.5 h. It will be important to monitor adoption of extended window thrombolysis in the US, and determine if additional RCT data are required to change practice.