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

BACKGROUND: Recent randomized controlled trials of endovascular treatment (EVT) for distal and medium vessel occlusion (DMVO) stroke did not demonstrate clinical benefit over best medical therapy and suggested potential safety concerns. We aimed to compare baseline characteristics of patients with DMVO stroke enrolled in these trials with those treated with EVT in routine clinical practice (RCP). METHODS: We conducted a retrospective cohort study of a prospectively recorded dual-center database including all consecutive patients with an acute ischemic stroke due to isolated primary DMVO (distal or nondominant M2, M3, A1, A2, A3, P1, P2) between January 2022 and July 2024 who fulfilled trials inclusion/exclusion criteria. Both centers participated in the DMVO trials during the study period. Patients were categorized in 2 groups: those who underwent EVT under RCP (RCP group) versus those randomized in a trial for DMVO stroke (clinical trial, computed tomography group). The 2 groups were evaluated and compared based on demographic, clinical, imaging, and treatment characteristics. RESULTS: Among 182 patients (median age, 79 years; interquartile range IQR, 69–86; 46.2% female), 53 (29.1%) were included in a trial, and 129 (70.9%) were treated in RCP. Compared with RCP patients, those in the computed tomography group presented lower baseline stroke severity (median NIHSS, 5 IQR, 4–7 versus 10 IQR,7–15; P <0.001), smaller admission hypoperfusion volumes (27 mL IQR, 16–42 versus 48 mL IQR, 24–70; P <0.001) and a trend toward more vascular risk factors (2, IQR, 1–3 versus 1 1–2 in RCP patients; P =0.062) was observed. Angiographic outcomes among patients undergoing EVT trended toward higher successful reperfusion in the RCP group (87.6% versus 72.0%; P =0.051). CONCLUSIONS: In our study, conducted at 2 centers participating in DMVO clinical trials, randomized patients presented milder clinical severity and smaller hypoperfusion areas compared with those treated in daily practice, suggesting a potential selection bias. Our findings highlight the importance of consecutive recruitment in future DMVO trials to clarify the role of EVT.