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Effect of definition and methods on estimates of prevalence of large vessel occlusion in acute ischemic stroke: a systematic review and meta-analysis
  1. Muhammad Waqas1,2,
  2. Ansaar T Rai3,
  3. Kunal Vakharia1,2,
  4. Felix Chin2,
  5. Adnan H Siddiqui3,4
  1. 1 Neurosurgery, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York, USA
  2. 2 Neurosurgery, Gates Vascular Institute, Buffalo, New York, USA
  3. 3 Department of Neurointerventional Radiology, West Virginia University, Morgantown, West Virginia, USA
  4. 4 Departments of Neurosurgery and Radiology and Toshiba Stroke Research Center, University at Buffalo, State University of New York, Buffalo, New York, USA
  1. Correspondence to Dr. Adnan H Siddiqui, Departments of Neurosurgery and Radiology and Toshiba Stroke Research Center, University at Buffalo, State University of New York, Buffalo, NY 14260, USA ; asiddiqui{at}, adnan.h.siddiqui{at}


Introduction Accurate estimation of the incidence of large vessel occlusion (LVO) is critical for planning stroke systems of care and approximating workforce requirements. This systematic review aimed to estimate the prevalence of LVO among patients with acute ischemic stroke (AIS), with emphasis on definitions and methods used by different studies.

Methods A systematic literature review was performed to search for articles on the prevalence of LVO and AIS. All articles describing the frequency of LVO frequency among AIS patients were included. Studies without consecutive recruitment or confirmation of LVO with CT angiography or MR angiography were excluded. Heterogeneity of the studies was assessed; meta-regression was performed to estimate the effect of LVO definition and study methods on LVO prevalence.

Results 18 articles met the inclusion criteria: 5 studies presented population based estimates; 13 provided single hospital experiences (5 prospective, 8 retrospective). The AIS denominator (number of all AIS) from which LVO rates were generated was variable. Nine different definitions were used, based on occlusion site. Significant heterogeneity existed among the studies (I2=99%, P<0.001). The prevalence of LVO among patients with suspected AIS ranged from 13% to 52%. Overall prevalence was 30.0% (95% CI 25.0% to 35.0%). Pooled prevalence of LVO among suspected AIS patients was 21% (95% CI 19% to 30%). Based on meta-regression, the method of AIS denominator determination significantly influenced heterogeneity (P=0.018).

Conclusion The heterogeneity of LVO estimates was remarkably high. The method of AIS denominator determination was the most significant predictor of LVO estimates. Studies with a standardized LVO definition and methods of AIS estimation are necessary to estimate the true prevalence of LVO among patients with AIS.

  • large vessel occlusion
  • acute ischemic stroke
  • population-based studies
  • large vessel occlusion definition
  • systematic review

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  • Contributors Conception and design: ATR and MW. Acquisition of the data: all authors. Analysis and interpretation of the data: all authors. Drafting the manuscript: MW. Critically revising the manuscript: all authors. Reviewed submitted version of manuscript: all authors.

  • 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 ATR: consulting agreement with Stryker Neurovascular and Cerenovus Siddiqui; financial interest/investor/stock options/ownership in Amnis Therapeutics, Apama Medical, Blink TBI Inc, Buffalo Technology Partners Inc, Cardinal Consultants, Cerebrotech Medical Systems Inc, Cognition Medical, Endostream Medical Ltd, Imperative Care, International Medical Distribution Partners, Neurovascular Diagnostics Inc, Q’Apel Medical Inc, Rebound Therapeutics Corp, Rist Neurovascular Inc, Serenity Medical Inc, Silk Road Medical, StimMed, Synchron, Three Rivers Medical Inc, Viseon Spine Inc; consultant/advisory board for Amnis Therapeutics, Boston Scientific, Canon Medical Systems USA Inc, Cerebrotech Medical Systems Inc, Cerenovus, Corindus Inc, Endostream Medical Ltd, Guidepoint Global Consulting, Imperative Care, Integra LifeSciences Corp, Medtronic, MicroVention, Northwest University–DSMB Chair for HEAT Trial, Penumbra, Q’Apel Medical Inc, Rapid Medical, Rebound Therapeutics Corp, Serenity Medical Inc, Silk Road Medical, StimMed, Stryker, Three Rivers Medical Inc, VasSol, WL Gore and Associates; principal investigator/steering comment of the following trials: Cerenovus LARGE and ARISE II, Medtronic SWIFT PRIME and SWIFT DIRECT, MicroVention FRED and CONFIDENCE, MUSC POSITIVE, and Penumbra 3D Separator, COMPASS, and INVEST.

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

  • Data sharing statement All study data are included in the manuscript and supplementary material.

  • Patient consent for publication Not required.