Faculty, Staff and Student Publications

Language

English

Publication Date

2-1-2026

Journal

Stroke

DOI

10.1161/STROKEAHA.125.052355

PMID

41221581

PMCID

PMC12829500

PubMedCentral® Posted Date

11-12-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Background: It remains unclear whether outcomes of patients treated with endovascular thrombectomy with large-vessel occlusion and unwitnessed onset of stroke differ from those with witnessed onset in the extended time window.

Methods: We enrolled patients with anterior circulation large-vessel occlusion (internal carotid artery, M1, or M2 segment of the middle cerebral artery) undergoing endovascular thrombectomy within 6 to 24 hours from the time last seen well, from 2014 to 2022, at 66 sites in Europe, North America, and Asia. Patients with a prestroke modified Rankin Scale score of >3 or age < 18 were excluded. We categorized patients by onset mode as witnessed or unwitnessed. The primary outcome was the modified Rankin Scale shift at 90 days. Secondary outcomes were functional independence, a composite of functional independence or return of Rankin to prestroke level, symptomatic intracranial hemorrhage, mortality, and a composite of severe disability or mortality at 90 days. We applied inverse probability of treatment weighting to compare outcomes between the groups.

Results: Of 5098 patients assessed for eligibility, we included 2073, of whom 1760 (84.9%) had unwitnessed onset, and 313 (15.1%) were witnessed. In the univariate comparison (before inverse probability of treatment weighting), 38.8% of the unwitnessed and 45.7% of the witnessed patients achieved functional independence (P=0.022). Mortality was 21.6% among unwitnessed and 22.0% among witnessed (P=0.847), and symptomatic intracranial hemorrhage rates were 6.6% and 5.8%, respectively (P=0.623). The primary outcome (modified Rankin Scale shift) showed no difference comparing unwitnessed to witnessed patients (odds ratio, 1.35 [95% CI, 0.82-2.20]; P=0.235) in the inverse probability of treatment weighting. Unwitnessed patients were more likely to achieve functional independence or return of Rankin (1.53 [1.01-2.33]; P=0.045). Other secondary outcomes did not differ between the witnessed and unwitnessed patients.

Conclusions: In the extended time window, unwitnessed patients with large-vessel occlusion undergoing endovascular thrombectomy have at least the same likelihood of favorable outcomes as witnessed patients.

Keywords

Aged, Aged, 80 and over, Female, Humans, Male, Middle Aged, Endovascular Procedures, Ischemic Stroke, Stroke, Thrombectomy, Time Factors, Time-to-Treatment, Treatment Outcome, intracranial hemorrhage, ischemic stroke, middle cerebral artery, thrombectomy, tomography

Published Open-Access

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