ELATE Study: Evaluating Large-vessel Acute Thrombectomy in Extended Time Window (ELATE)

Endovascular thrombectomy (EVT) is an established treatment for patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO) presenting within 24 hours of stroke onset or last known well (LKW). Although landmark trials such as DAWN and DEFUSE 3 used advanced neuroimaging techniques, including CT perfusion (CTP) and MR perfusion (MRP), to identify eligible patients within 6-24 hours, the role of EVT beyond this time window remains insufficiently investigated. This evidence gap is particularly relevant in low- and middle-income countries (LMICs), including Vietnam, where limited public awareness of stroke symptoms, underdeveloped prehospital emergency medical services, and delays in hospital presentation contribute to a substantial proportion of patients presenting in the very late time window. Furthermore, limited access to advanced neuroimaging may restrict treatment opportunities for patients who could potentially benefit from EVT. Therefore, this prospective observational study aims to evaluate clinical outcomes following endovascular thrombectomy compared with best medical treatment in patients with AIS due to anterior circulation LVO presenting 24-72 hours after stroke onset or LKW. Eligible patients are selected based on clinical and imaging criteria, including significant neurological deficits and evidence of potentially salvageable brain tissue, assessed by either perfusion mismatch on CT or MR perfusion imaging or an ASPECTS-based imaging criterion. The findings may provide further evidence regarding the potential role of EVT in this extended time window and help inform clinical decision-making.