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Endovascular thrombectomy beyond 24 hours from ischemic stroke onset: a propensity score matched cohort study
  1. Permesh Singh Dhillon1,2,
  2. Waleed Butt3,
  3. Anna Podlasek2,
  4. Emma Barrett4,5,
  5. Norman McConachie1,
  6. Robert Lenthall1,
  7. Sujit Nair1,
  8. Luqman Malik1,
  9. Martin A James6,7,8,
  10. Robert A Dineen2,9,
  11. Timothy J England10,11
  1. 1Interventional Neuroradiology, Queens Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham, UK
  2. 2NIHR Nottingham Biomedical Research Centre, Nottingham, UK
  3. 3Interventional Neuroradiology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS Trust, Birmingham, UK
  4. 4Department of Research and Innovation (Medical Statistics), Manchester University NHS Foundation Trust, Manchester, UK
  5. 5Centre for Biostatistics, Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
  6. 6Exeter Medical School, University of Exeter, Exeter, UK
  7. 7Stroke, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
  8. 8Sentinel Stroke National Audit Programme, King’s College London, London, UK
  9. 9Radiological Sciences, Mental Health and Clinical Neuroscience, University of Nottingham, Nottingham, UK
  10. 10Stroke Trials Unit, Mental Health & Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, UK
  11. 11Stroke, University Hospitals of Derby and Burton NHS Foundation Trust, Derby, UK
  1. Correspondence to Dr Permesh Singh Dhillon, B Floor, Interventional Neuroradiology, Queens Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham NG7 2UH, UK; permesh.dhillon{at}


Background The safety and functional outcome of endovascular thrombectomy (EVT) in the very late (VL; >24 hours) time window from ischemic stroke onset remains undetermined.

Methods Using data from a national stroke registry, we used propensity score matched (PSM) individual level data of patients who underwent EVT, selected with CT perfusion or non-contrast CT/CT angiography, between October 2015 and March 2020. Functional and safety outcomes were assessed in both late (6–24 hours) and VL time windows. Subgroup analysis was performed of imaging selection modality in the VL time window.

Results We included 1150 patients (late window: 1046 (208 after PSM); VL window: 104 (104 after PSM)). Compared with EVT treatment initiation between 6 and 24 hours, patients treated in the VL window had similar modified Rankin Scale (mRS) scores at discharge (ordinal shift; common OR=1.08, 95% CI 0.69 to 1.47, p=0.70). No significant differences in achieving good functional outcome (mRS ≤2 at discharge; 28.8% (VL) vs 29.3% (late), OR=0.97, 95% CI 0.58 to 1.64, p=0.93), successful reperfusion (modified Thrombolysis in Cerebral Infarction score of 2b–3) (p=0.77), or safety outcomes of symptomatic intracranial hemorrhage (p=0.43) and inhospital mortality (p=0.23) were demonstrated. In the VL window, there was no significant difference in functional outcome among patients selected with perfusion versus those selected without perfusion imaging (common OR=1.38, 95% CI 0.81 to 1.76, p=0.18).

Conclusion In this real world study, EVT beyond 24 hours from stroke onset or last known well appeared to be feasible, with comparable safety and functional outcomes to EVT initiation between 6 and 24 hours. Randomized trials assessing the efficacy of EVT in the VL window are warranted, but may only be feasible with a large international collaborative approach.

  • thrombectomy
  • stroke
  • CT perfusion
  • CT angiography

Data availability statement

Data may be obtained from a third party and are not publicly available. Data access requests should be directed to SSNAP as the data provider and the HQIP as the data controller.

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Data availability statement

Data may be obtained from a third party and are not publicly available. Data access requests should be directed to SSNAP as the data provider and the HQIP as the data controller.

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  • Contributors Conception and design: PSD and WB. Acquisition of the data: PSD. Analysis and interpretation of the data: PSD, EB, AP, and WB. Critical revision of the manuscript: PSD, WB, AP, EB, NM, RL, SN, LM, MAJ, RAD, and TJE. Study supervision: RAD and TJE. All authors approved the final version of the manuscript. Guarantor of this work: PSD.

  • Funding SSNAP is commissioned by the Health Quality Improvement Partnership and funded by National Health Service (NHS) England and the Welsh Government. MAJ is supported by the National Institute for Health Research Applied Research Collaboration South West Peninsula.

  • Disclaimer The views expressed in this publication are those of the author(s) and not necessarily those of the National Institute for Health Research or the Department of Health and Social Care. No specific funding was sought for this study.

  • Competing interests MAJ has received lecture and consultancy fees from Medtronic.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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