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Original research
What to do about fibrin rich ‘tough clots’? Comparing the Solitaire stent retriever with a novel geometric clot extractor in an in vitro stroke model
  1. Vernard S Fennell1,
  2. Swetadri Vasan Setlur Nagesh2,
  3. Karen M Meess3,4,5,
  4. Liza Gutierrez6,
  5. Rhys H James3,
  6. Michael E Springer3,
  7. Adnan H Siddiqui3,7
  1. 1 Department of Neurosurgery, University at Buffalo, State University of New York, Buffalo, New York, USA
  2. 2 Toshiba Stroke & Vascular Research Center, University at Buffalo, State University of New York, Buffalo, New York, USA
  3. 3 Jacobs Institute, Buffalo, New York, USA
  4. 4 Department of Biomedical Engineering, University at Buffalo, State University of New York, Buffalo, New York, USA
  5. 5 CUBRIC Inc, Buffalo, New York, USA
  6. 6 Toshiba Stroke and Vascular Research Center, University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, New York, USA
  7. 7 Departments of Neurosurgery and Radiology, Toshiba Stroke Research Center, University at Buffalo, State University of New York, Buffalo, New York, USA
  1. Correspondence to Dr Adnan H Siddiqui, University at Buffalo Neurosurgery, 100 High Street, Suite B4, Buffalo, NY 14203, USA; asiddiqui{at}


Background Despite advances in revascularization tools for large vessel occlusion presenting as acute ischemic stroke, a significant subset of clots remain recalcitrant to current strategies. We assessed the effectiveness of a novel thrombectomy device that was specifically designed to retrieve resistant fibrin rich clots, the geometric clot extractor (GCE; Neuravi, Galway, Ireland), in an in vitro cerebrovascular occlusion stroke model.

Methods After introducing fibrin rich clot analogues into the middle cerebral artery of the model, we compared the rates of recanalization between GCE and Solitaire flow restoration stent retriever (SR; Medtronic, Minneapolis, Minnesota, USA; control group) cases. A maximum of three passes of each device was allowed. If the SR failed to recanalize the vessel after three passes, one pass of the GCE was allowed (rescue cases).

Results In a total of 26 thrombectomy cases (13 GCE, 13 SR), successful recanalization (Thrombolysis in Cerebral Infarction score of 2b or 3) was achieved 100% of the time in the GCE cases with an average of 2.13 passes per case. This rate was significantly higher compared with the Solitaire recanalization rate (7.7%, P<0.0001) with an average of three passes per case. After SR failure (in 92% of cases), successful one pass GCE rescue recanalization was achieved 66% of the time (P<0.005).

Conclusion Application of the GCE in this experimental stroke model to retrieve typically recalcitrant fibrin rich clots resulted in higher successful recanalization rates than the SR.

  • flow diverter
  • stroke
  • thrombectomy
  • technique
  • technology

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  • VSF and SVSN contributed equally.

  • Contributors Conception and design: AHS, VSF, SVSN, and KMM. Data acquisition: VSF, SVSN, KMM, and LG. Data analysis and interpretation: all authors. Drafting the manuscript: SVSN, VSF, and AHS. Critically revising the manuscript: all authors. Final approval of the manuscript: all authors.

  • Funding Funding and devices were provided by Neuravi Ltd. Data collection, analysis, and interpretation of results was performed by the authors, independent of company input; and all content is solely the responsibility of the authors.

  • Competing interests AHS declares the following competing interests: Financial interests: Apama Medical, Buffalo Technology Partners Inc., Cardinal Health, Endostream Medical Ltd., International Medical Distribution Partners, Medina Medical Systems, Neuro Technology Investors, StimMed, Valor Medical; Consultant:Amnis Therapeutics Ltd., Cerebrotech Medical Systems Inc., Cerenovus (formerly Codman Neurovascular, Neuravi, and Pulsar Vascular), CereVasc LLC, Claret Medical Inc., Corindus Inc., GuidePoint Global Consulting, Integra (formerly Codman Neurosurgery), Medtronic (formerly Covidien), MicroVention, Penumbra, Rapid Medical, Rebound Therapeutics Corporation , Silk Road Medical, Stryker, The Stroke Project Inc., Three Rivers Medical Inc., Toshiba America Medical Systems Inc., W.L. Gore & Associates; Principal Investigator/National Steering Committees: Codman & Shurtleff LARGE Aneurysm Randomized Trial, Covidien (now Medtronic) SWIFT PRIME and Solitaire With the Intention For Thrombectomy Plus Intravenous t-PA Versus DIRECT Solitaire Stent-retriever Thrombectomy in Acute Anterior Circulation Stroke (SWIFT DIRECT) trials, MicroVention CONFIDENCE Study and FRED Trial: Flow Diversion Versus Traditional Endovascular Coiling Therapy, Penumbra 3D Separator Trial, Penumbra COMPASS, and INVEST trials, MUSC POSITIVE trial, Neuravi ARISE II Trial Steering Committee; Board Member:Intersocietal Accreditation Committee. (Dr. Siddiqui receives no consulting salary arrangements. All consulting is per project and/or per hour.) All other authors declare no competing interests.

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

  • Data sharing statement Additional data may be made available by contacting the corresponding author.