Abstract A083: Safety and feasibility of direct-to-angio among transferred patients receiving EVT in late time window – a secondary analysis of a retrospective cohort study

Introduction: Direct-to-angio(DTA) approach has been shown to reduce time to endovascular thrombectomy(EVT) and is associated with improved functional outcomes, but detailed evaluation of DTA approach in late and very late windows has not been explored yet. We aimed to assess the association of DTA vs repeat imaging(RI) approach with functional and safety outcomes across <6hr vs ≥ 6hr and <12hr vs ≥12hr time windows. Methods: In a secondary analysis of a retrospective cohort study, transferred patients who received EVT under DTA vs RI approach were stratified based on time from last known well(LKW) to procedure into <6hr vs ≥ 6hr and <12hr vs ≥12hr. The association of DTA vs RI approach with functional and safety outcomes were assessed using appropriate regression models, adjusted for age, occlusion location, stroke severity, serum glucose, time to procedure and successful reperfusion(mTICI 2b-3) status. Results: Of 1140 participants, 621(54%) received EVT <6 hours(DTA:202, RI:419) and 519(46%) received EVT ≥6 hours(DTA:125, RI:394) – of which 196(17%) received EVT ≥12 hours(DTA:47, RI:149). Age, sex, stroke severity and anesthesia type were similar, however, DTA patients had lower serum glucose and more frequent witnessed stroke onset. Better functional outcome with DTA sustained among <12hr(acOR:1.44, 95%CI:1.09-1.90, p=0.01) vs ≥12hr(acOR:2.60, 95%CI:1.32-5.13, p=0.006, p-int=0.19), with similer other functional outcomes. sICH was similar across <12hr(DTA:9.4% vs RI:9.9%, aOR:1.09, 95%CI:0.65-1.83, p=0.73) and ≥12hr(DTA:4.3% vs RI:11.6%, aOR:0.16, 95%CI:0.02-1.35, p=0.09, p-int=0.16). Both low (NIHSS<15) and high NIHSS (≥15) at presentation had improved outcomes with DTA among ≥12hr (<15: acOR:2.79, 95%CI: 0.90-8.66, p=0.075, ≥15: acOR:3.03, 95%CI: 1.29-7.09, p=0.011, p-int=0.83). Similar results were also observed across <6hr vs ≥6hr. Conclusions: Association of DTA with improved outcomes persevered ≥6 and ≥12hr of LKW, without an increase in symptomatic hemorrhage, including patients with both low and high stroke severity. These exploratory findings suggest that feasibility of DTA approach can be extended to EVT patients in late and very late time window without undue safety risks.