Eligibility for Endovascular Trial Enrollment in the 6- to 24-Hour Time Window: Analysis of a Single Comprehensive Stroke Center

Background and purpose: The results of the DAWN trial (Diffusion-Weighted Imaging or Computerized Tomography Perfusion Assessment With Clinical Mismatch in the Triage of Wake Up and Late Presenting Strokes Undergoing Neurointervention With Trevo) support the benefit of endovascular therapy in patients presenting beyond the 6-hour time window with anterior circulation large vessel occlusions. The impact of these results with respect to additional number of eligible patients in clinical practice remains unknown.

Methods: A retrospective review of ischemic stroke admissions to a single DAWN trial-participating comprehensive stroke center was performed during the DAWN enrollment period (November 2014 to February 2017) to identify patients meeting criteria for DAWN and DEFUSE-3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke-3) eligibility. Patients presenting beyond 6 hours were further investigated to clarify reasons for trial exclusion.

Results: Of the 2667 patients with acute ischemic stroke admitted within the study period, 30% (n=792) presented within the 6- to 24-hour time window, and 47% (n=1242) had a National Institutes of Health Stroke Scale ≥6. Further clinical trial-specific selection criteria were applied based on the presence of large vessel occlusion, baseline modified Rankin Scale score, core infarct, and perfusion imaging (when available). There were 45 patients who met all DAWN trial criteria and 47 to 58 patients who would meet DEFUSE-3 trial criteria. Thirty-three percent of DAWN-eligible patients are DEFUSE-3 ineligible.

Conclusions: Of all patients with acute ischemic stroke presenting to a single comprehensive stroke center, 1.7% of patients qualified for DAWN clinical trial enrollment with an additional 0.6% to 1% qualifying for the DEFUSE-3 trial. These data predict an increase in thrombectomy utilization with important implications for comprehensive stroke center resource optimization and stroke systems of care.