ABSTRACT NUMBER: ESOC2026A1823 A DETAILED ANALYSIS OF FIRST PASS REPERFUSION AND NUMBER OF PASSES IN MEVO STROKE THROMBECTOMY

Abstract Background and aims Acute stroke due to medium-vessel occlusion (MeVO) represents a distinct subgroup with unproven benefit of endovascular treatment (EVT). Reperfusion success after EVT and the number of EVT passes may be associated with clinical and imaging outcomes in MeVO strokes. Methods Secondary analysis of patients randomized to EVT in the ESCAPE-MeVO trial. Final reperfusion was assessed with the MeVO-expanded Thrombolysis in Cerebral Infarction (MeVO-eTICI) Score. First pass near-complete reperfusion was defined as MeVO-eTICI 2c-3 after 1 pass and multi-pass near-complete reperfusion as MeVO-eTICI 2c-3 after >1 pass. The primary outcome was the modified Rankin Score (mRS) at 90 days. Secondary outcomes included 90-day mRS 0-1, mRS 0-2, mortality, 24-hour infarct volume and symptomatic intracranial hemorrhage. Associations were assessed using regression models. Results Of 255 patients randomized to EVT (48.3%), 206 remained for the final analysis. First pass near-complete reperfusion was associated with decreased infarct volume (median 12.8ml [IQR 0.15-25.3] versus: 22.4ml [6.71-56.38 ml], adjusted beta-coefficient-1.68 [95%CI:-2.54–(-0.81)]), but not with clinical outcomes. Similarly, improved reperfusion status was associated with lower infarct volumes (adjusted beta-coefficient -0.98[95%CI:-1.38–(-0.57)]) only. Number of EVT passes was associated with higher 90-day mRS (acOR 1.41[95%CI:1.04-1.91] per 1-additional pass) and larger infarct volume (adjusted beta-coefficient 1.12[95%CI:0.63-1.61]). Conclusions Achieving first pass near-complete reperfusion with EVT in MeVO stroke patients was associated with reduced infarct volumes without resulting in improved clinical outcomes. Performing more EVT passes was associated with increased infarct volume and poorer outcomes. Conflict of interest Alexander Stebner: nothing to disclose, Salome Bosshart: nothing to disclose, Dar Dowlatshahi: nothing to disclose, Shahid Nimjee: nothing to disclose, Mouhammad Jumaa: nothing to disclose, Markus Möhlenbruch: nothing to disclose, David Volders: nothing to disclose, Michael D. Hill: reports grants from Canadian Institutes for Health Research, Alberta Innovates, and NoNO, for the conduct of the study; reports personal fees from Merck; reports non-financial support from Hoffmann-La Roche Canada; reports grants from Covidien (Medtronic), Boehringer-Ingleheim, Stryker, and Medtronic, outside the submitted work; reports a patent for systems and methods for assisting in decision-making and triaging for acute stroke patients, issued to US Patent office Number 62/086,077; owns stock in Calgary Scientific; is a director of the Canadian Federation of Neurological Sciences and Circle NeuroVascular; and has received grant support from Alberta Innovates Health Solutions, CIHR, Heart & Stroke Foundation of Canada, and the National Institutes of Neurological Disorders and Stroke, Mayank Goyal: holds grants from Johnson & Johnson and Medtronic and is a consultant to Medtronic, Mentice, Microvention, Philips and Stryker, Johanna Ospel: is a consultant for Nicolab.