Abstract 78: Time to Endovascular Treatment and Outcomes in the DAWN Trial

Abstract

Introduction: It is well-established that, within 0-6 hours, the benefit of thrombectomy rapidly decays over time. The DAWN trial demonstrated that, in the presence of clinical-core mismatch (CCM), thrombectomy remains beneficial within 6-24 hours. We aim to assess the effect of time to randomization on outcomes in the DAWN. Methods: We used traditional multivariate logistic regression controlling age and NIHSS at baseline adding an interaction between Trevo and Time last seen well and then generated the odds ratio of the interaction of Trevo and time at particular time points. Results: Each 1-hour delay to treatment markedly impacted functional independence (OR,0.89 [95% CI 0.75 to 1.03]). Although the odds of functional independence at 90 days (mRS 0-2) with thrombectomy declined with longer time from last seen well (TLSW) to puncture, treatment benefit was observed through 24 hours : cOR at 8 hours, 6.8 (95% CI, 2.1 to 22.0), absolute risk difference (ARD) for mRS 0-2, 24.4%; cOR at 12 hours, 9.4 (95% CI, 4.1 to 21.6), ARD, 35.1%; cOR at 16 hours, 13.0 (95% CI, 4.1 to 41.3), ARD, 37.2%; cOR at 20 hours, 17.8 (95% CI, 2.9 to 110.4), ARD, 36.5%; cOR at 24 hours, 24.6 (95% CI, 1.9 to 322), ARD, 35.5% (Figure). Comparable analysis using time from symptoms first observed (TSFO) yielded similar results. Conclusion: In patients selected based on CCM, treatment benefit persists all the way to 24 hours; however, both the chances of good outcome and the overall treatment effect continuously drop over time.