Mechanical Thrombectomy in the Late Presentation of Anterior Circulation Large Vessel Occlusion Stroke: A Guideline From the Society of Vascular and Interventional Neurology Guidelines and Practice Standards Committee

Background Recent clinical trials investigating endovascular therapy in the extended time window have opened new treatment paradigms for patients with late‐presenting large vessel occlusion stroke. The aim of this guideline is to provide up‐to‐date recommendations for the diagnosis, selection, and medical or endovascular treatment of patients with large vessel occlusion presenting in the extended time window. Methods The Society of Vascular and Interventional Neurology Guidelines and Practice Standards committee assembled a writing group and recruited interdisciplinary experts to review and evaluate the current literature. Recommendations were assigned by the writing group using the Society of Vascular and Interventional Neurology Guidelines and Practice Standards Class of Recommendation/Level of Evidence algorithm and Society of Vascular and Interventional Neurology Guidelines and Practice Standards guideline format. The final guideline was approved by all members of the writing group, the Guidelines and Practice Standards committee, and the Society of Vascular and Interventional Neurology board of directors. Results Literature review yielded 3 high‐quality randomized trials and several observational studies that have been extracted to derive the enclosed summary recommendations. In patients with large vessel occlusion presenting in the 6‐ to 24‐hour window and with clinical–imaging mismatch as defined by the DAWN (Diffusion‐Weighted Imaging or Computed Tomography Perfusion Assessment With Clinical Mismatch in the Triage of Wake‐Up and Late Presenting Strokes Undergoing Neurointervention With Trevo) and DEFUSE 3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke) studies, endovascular therapy is recommended. Noncontrast computed tomography can be used to evaluate infarct size as the sole imaging modality for patient selection, particularly when access to computed tomography perfusion or magnetic resonance imaging is limited or if their performance would incur substantial delay to treatment. In addition, several clinical questions were reviewed based on the available evidence and consensus grading. Conclusions These guidelines provide practical recommendations based on recent evidence on the diagnosis, selection, and treatment of patients with large vessel occlusion stroke presenting in the extended time window.