Association between time to treatment and clinical outcomes in endovascular thrombectomy beyond 6 hours without advanced imaging selection

Permesh Singh Dhillon (Lead / Corresponding author), Waleed Butt, Anna Podlasek, Norman McConachie, Robert Lenthall, Sujit Nair, Luqman Malik, Pervinder Bhogal, Hegoda Levansri Dilrukshan Makalanda, Oliver Spooner, Kailash Krishnan, Nikola Sprigg, Alex Mortimer, Thomas Calvert Booth, Kyriakos Lobotesis, Philip White, Martin A. James, Philip Bath, Robert A. Dineen, Timothy J. England

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Background: The effectiveness and safety of endovascular thrombectomy (EVT) in the late window (6-24 hours) for acute ischemic stroke (AIS) patients selected without advanced imaging is undetermined. We aimed to assess clinical outcomes and the relationship with time-to-EVT treatment beyond 6 hours of stroke onset without advanced neuroimaging. 

Methods: Patients who underwent EVT selected with non-contrast CT/CT angiography (without CT perfusion or MR imaging), between October 2015 and March 2020, were included from a national stroke registry. Functional and safety outcomes were assessed in both early (<6 hours) and late windows with time analyzed as a continuous variable. 

Results: Among 3278 patients, 2610 (79.6%) and 668 (20.4%) patients were included in the early and late windows, respectively. In the late window, for every hour delay, there was no significant association with shift towards poorer functional outcome (modified Rankin Scale (mRS)) at discharge (adjusted common OR 0.98, 95% CI 0.94 to 1.01, p=0.27) or change in predicted functional independence (mRS ≤2) (24.5% to 23.3% from 6 to 24 hours; aOR 0.99, 95% CI0.94 to 1.04, p=0.85). In contrast, predicted functional independence was time sensitive in the early window: 5.2% reduction per-hour delay (49.4% to 23.5% from 1 to 6 hours, p=0.0001). There were similar rates of symptomatic intracranial hemorrhage (sICH) (3.4% vs 4.6%, p=0.54) and in-hospital mortality (12.9% vs 14.6%, p=0.33) in the early and late windows, respectively, without a significant association with time. 

Conclusion: In this real-world study, there was minimal change in functional disability, sICH and in-hospital mortality within and across the late window. While confirmatory randomized trials are needed, these findings suggest that EVT remains feasible and safe when performed in AIS patients selected without advanced neuroimaging between 6-24 hours from stroke onset.

Original languageEnglish
Pages (from-to)336–342
Number of pages7
JournalJournal of Neurointerventional Surgery
Issue number4
Early online date16 Mar 2022
Publication statusPublished - 18 May 2023


  • CT angiography
  • CT perfusion
  • intervention
  • stroke
  • thrombectomy

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


Dive into the research topics of 'Association between time to treatment and clinical outcomes in endovascular thrombectomy beyond 6 hours without advanced imaging selection'. Together they form a unique fingerprint.

Cite this