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Original research
Stroke imaging modality for endovascular therapy in the extended window: systematic review and meta-analysis
  1. Joel M Sequeiros1,
  2. Aaron Rodriguez-Calienes2,
  3. Sandra S Chavez-Malpartida3,4,5,
  4. Cristian Morán-Mariños6,7,
  5. Giancarlo Alvarado-Gamarra4,8,9,
  6. Marco Malaga4,
  7. Alvaro Quincho-Lopez3,
  8. Wendy Hernadez-Fernandez5,
  9. Kevin Pacheco-Barrios10,11,
  10. Santiago Ortega-Gutierrez12,
  11. Daniel Hoit13,
  12. Adam S Arthur13,
  13. Andrei V Alexandrov1,
  14. Carlos Alva-Diaz2,5,
  15. Lucas Elijovich1,13
  1. 1 Department of Neurology, University of Tennessee Health Science Center, Memphis, Tennessee, USA
  2. 2 Grupo de Investigacion Neurociencia, Efectividad Clinica y Salud Publica, Universidad Científica del Sur, Lima, Peru
  3. 3 Facultad de Medicina Humana, Universidad Nacional Mayor de San Marcos, Lima, Peru
  4. 4 Red de Eficacia Clínica y Sanitaria, REDECS, Lima, Peru
  5. 5 Servicio de Neurologia, Departamento de Medicina y Oficina de Apoyo a la Docencia e Investigacion, Hospital Daniel Alcides Carrion, Callao, Peru
  6. 6 Unidad de Investigacion en Bibliometria, Universidad San Ignacio de Loyola, Lima, Peru
  7. 7 Servicio de Neumologia, Hospital Nacional Dos de Mayo, Lima, Peru
  8. 8 Departamento de Pediatria, Hospital Nacional Edgardo Rebagliati Martins, Lima, Peru
  9. 9 Departamento de Pediatria, Instituto de Investigación Nutricional, Lima, Peru
  10. 10 Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Boston, Massachusetts, USA
  11. 11 Vicerrectorado de Investigacion, Unidad de Investigacion para la Generacion y Síntesis de Evidencias en Salud, Universidad San Ignacio de Loyola, Lima, Peru
  12. 12 Department of Neurology, Neurosurgery and Radiology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
  13. 13 Department of Neurosurgery, University of Tennessee Health Science Center – Semmens Murphy Clinic, Memphis, TN, USA
  1. Correspondence to Dr Joel M Sequeiros, University of Tennessee Health Science Center, Memphis, TN 38163, USA; jsequei1{at}


Background In anterior circulation large vessel occlusion (LVO) in the extended time window, the guidelines recommend advanced imaging (ADVI) to select patients for endovascular therapy (EVT). However, questions remain regarding its availability and applicability in the real world. It is unclear whether an approach to the extended window EVT that does not use ADVI would be equivalent.

Methods In April 2022, a literature search was performed to identified randomized controlled trials (RCT) and observational studies describing 90-day outcomes. We performed a meta-analysis of the proportion of aggregate using a random effect to estimate rates of functional independence, defined as modified Rankin Scale (mRS) score ≤2 at 90 days, mean mRS, mortality and symptomatic intracranial hemorrhage (sICH) stratified by imaging modality.

Results Four RCTs and 28 observational studies were included. The pooled proportion of functional independence among patients selected by ADVI was 44% (95% CI 39% to 48%; I2=80%) and 48% (95% CI 41% to 55%; I2=75%) with non-contrast CT/CT angiography (NCCT/CTA) (p=0.36). Mean mRS with ADVI was 2.88 (95% CI 2.36 to 3.41; I2=0.0%) and 2.79 (95% CI 2.31 to 3.27; I2=0.0%) with NCCT (p=0.79). Mortality in patients selected by ADVI was 13% (95% CI 10% to 17%; I2=81%) and 16% (95% CI 12% to 22%; I2=69%) with NCCT (p=0.29). sICH with ADVI was 4% (95% CI 3% to 7%; I2=73%) and 6% with NCCT/CTA (95% CI 4% to 8%; I2=6%, p=0.27).

Conclusions Our study suggests that, in anterior circulation LVO, the rates of functional independence may be similar when patients are selected using ADVI or NCCT for EVT in the extended time window. A simplified triage protocol does not seem to increase mortality or sICH.

Protocol registration number (PROSPERO ID: CRD42021236092).

  • stroke
  • CT
  • thrombectomy

Data availability statement

Data are available upon reasonable request.

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Data availability statement

Data are available upon reasonable request.

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  • Twitter @joelsequeiros, @AaronCalienes, @Giancarlo, @CerebrovascLab, @AdamArthurMD

  • Contributors Conception and design of the study: JMS, CA-D, LE and AR-C. Acquisition and analysis of data: JMS, AR-C, SSC-M, MM, CM-M, GA-G, AQ-L, WH-F, CA-D and KP-B. Drafting a significant portion of the manuscript or figures: JMS, CA-D, LE, SO-G, DH, ASA, AVA, AR-C. Guarantor: JMS.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

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

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.