Abstract WMP8: Use, Characteristics, and Outcomes of Endovascular Thrombectomy in Acute Ischemic Stroke Patients Beyond 6 Hours of Stroke Onset in US Clinical Practice

Abstract

Introduction: Two recent RCTs have shown benefit of endovascular thrombectomy (EVT) in acute ischemic stroke (AIS) 6-24 h from last known well (LKW) using imaging-guided patient selection, however little is known about outcomes in contemporary non-trial settings. We assessed the frequency and outcomes of EVT beyond 6 h in the US national GWTG-Stroke clinical registry. Methods: We analyzed all AIS hospitalizations between 1/1/09 - 10/1/18 at fully participating GWTG-Stroke sites to identify 53,702 patients at 697 sites treated with EVT (± IV tPA) who had valid LKW, symptom discovery (SxD) and treatment times recorded. Hospital characteristics were analyzed at the 470 sites that treated > 10 patients during the study. Table 1 shows significant covariates (standardized differences >10%) and adjusted outcomes based on logistic regression models. Results: Treatment >6 h from LKW occurred in 33% of all EVT cases (median 4.7 h, IQR 3.3-7 h), and all were treated <6 h from SxD. The proportion of EVT cases treated >6 h from LKW varied widely across sites (median 30%, IQR 24-38%) and increased sharply in 2018 (Fig). Compared to < 6 h, patients treated >6 h differed in age, AF, arrival mode/time, stroke severity and use of anticoagulation, and presented to higher EVT volume centers. Late window EVT patients had less favorable adjusted outcomes at discharge for mortality, ambulation and disposition to home or IRF compared to <6 h patients (Table). Conclusions: EVT is frequently performed >6h, accounting for one-third of cases nationally. As adjusted functional outcomes at discharge are worse in these patients, further research is required to ensure optimal EVT outcomes in clinical practice settings