Abstract WP036: Endovascular Treatment for Medium and Distal Vessel Occlusion Stroke: Are We Missing the Point?

Introduction: Endovascular treatment (EVT) in combination with best medical management for the treatment of distal/medium vessel occlusion (DMVO) stroke failed to improve disability-related outcomes and was associated with a trend toward worse safety outcomes in three randomized controlled trials (RCTs) recently presented. Our aim was to compare baseline clinical characteristics of patients with DMVO stroke treated in routine clinical practice with those of patients enrolled in RCTs. HYPOTHESIS: The baseline clinical characteristics of patients included in RCTs differ from those of patients treated outside of RCTs. Methods: We conducted a retrospective comparative study using a prospectively recorded, dual-center, database of patients. We included all consecutive patients with an AIS due to isolated primary DMVO (distal or non-dominant M2, M3, A2, A3, P1, P2) who underwent EVT and/or were randomized into a distal occlusion clinical trial from January 2022 to July 2024. Patients were categorized as receiving EVT under routine clinical practice (RP group) or enrolled in a randomized clinical trial for DMVO stroke (clinical trial, CT group). Results: A total of 182 patients with an AIS due to isolated DMVO were included: median age was 79 (IQR 69-86) years, 84 (46.2%) patients were female, and the median baseline mRS was 1 (IQR 0-2). Fifty-three patients (29.1%) were in the CT group, and 129 (70.9%) in the RP group. CT patients showed a trend toward longer time from symptom onset to imaging (431 [IQR 150-630] minutes vs 265 [100-606]; p=0.149), presented lower baseline NIHSS score (5 [4-7] vs 10 [7-15]; p<0.001), higher cumulative vascular risk (41.5% vs 24.6% in RP group, p=0.024), and lower median hypoperfusion volume (Tmax<6s) on admission CTP (27 [16-42] vs 48 [24-70] p<0.001). CONCLUSIONS: Our study highlights potential selection bias in RCTs involving DMVO stroke, with trial patients presenting less severe strokes than those treated in routine clinical practice. These differences may limit the generalizability of RCT findings and emphasize the need for more representative trial designs.