To Use Perfusion Imaging or Not in Patient Selection for Late Window Endovascular Thrombectomy? That Is the Question

The DAWN (Clinical Mismatch in the Triage of Wake up and Late Presenting Strokes Undergoing Neurointervention with Trevo Thrombectomy Procedure)(1) and DEFUSE-3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3)(2) established the efficacy of endovascular thrombectomy (EVT) in selected patients presenting with a large vessel occlusion (LVO) in the anterior circulation and suspected symptom onset within the late window (last known well between 6 and 24 hours). Both trials selected candidates using CT perfusion (CTP) with eligibility confined to predefined core and penumbra thresholds quantified by an automated computer software. The results of DAWN and DEFUSE-3 have already been incorporated into the most recent guidelines from the American Heart Association/American Stroke Association(3) and the European Stroke Organization,(4) which strongly recommend EVT treatment up to 24 hours for patients with anterior circulation LVO if they satisfy either the DAWN or DEFUSE 3 eligibility criteria, inclusive of the respective core and penumbra thresholds on CTP.