DAWN Trial: Redefining the Treatment Window for Stroke Thrombectomy

Why DAWN Changed Stroke Care

The DAWN trial (DWI or CTP Assessment with Clinical Mismatch in the Triage of Wake-Up and Late-Presenting Strokes Undergoing Neurointervention with Trevo) redefined the timeline for treating ischemic stroke. By demonstrating that carefully selected patients could still benefit from thrombectomy up to 24 hours after symptom onset, DAWN shifted the paradigm of stroke systems of care.

Evidence to Date

DAWN used advanced imaging, including diffusion-weighted imaging (DWI) and computed tomography perfusion (CTP), to identify patients with a mismatch between clinical deficits and infarct core size. Patients receiving thrombectomy plus standard care had dramatically higher rates of functional independence compared to those receiving standard care alone. The trial quickly influenced guidelines and broadened eligibility for endovascular therapy, making imaging a central part of stroke triage.

Ongoing Debates and Research

Questions remain about how best to operationalize late-window thrombectomy. Not all hospitals have rapid access to perfusion imaging, and transfer delays can reduce benefit. Newer studies, such as DEFUSE 3, further confirm extended windows, but patient selection criteria continue to evolve. Additionally, efforts are underway to develop prehospital triage tools that could identify late-window candidates earlier.

Clinical Guidance for Physicians

Stroke teams should use CTP or magnetic resonance imaging (MRI) when considering thrombectomy beyond 6 hours, with DAWN criteria guiding selection. Systems of care should prioritize reducing delays from imaging to reperfusion. Even within extended windows, earlier treatment correlates with better outcomes.

Bottom Line

DAWN proved that “time is brain” extends beyond six hours—if patients are carefully selected. The trial ushered in an era where advanced imaging guides therapy, expanding opportunities for recovery while reinforcing the urgency of rapid systems-based stroke care.

Read more about the DAWN trial here

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