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Original research
An in vitro evaluation of distal emboli following Lazarus Cover-assisted stent retriever thrombectomy
  1. Ju-Yu Chueh,
  2. Ajit S Puri,
  3. Matthew J Gounis
  1. Department of Radiology, New England Center for Stroke Research, University of Massachusetts, Worcester, Massachusetts, USA
  1. Correspondence to Dr Matthew J Gounis, Department of Radiology, University of Massachusetts, 55 Lake Ave N, SA-107R, Worcester, MA 1655, USA; matthew.gounis{at}


Background Formation of clot fragments during mechanical thrombectomy for acute ischemic stroke can occlude the distal vasculature, which may reduce the rate of good clinical outcome.

Objective To examine the hypothesis that distal embolization can be reduced using stent retriever thrombectomy in combination with Lazarus Cover technology.

Methods Hard, fragment-prone clots were used to create middle cerebral artery occlusions in a vascular phantom. Three different treatment strategies using Solitaire FR included: group 1—proximal flow control with an 8F balloon guide catheter (BGC), group 2—thrombectomy through a 6F conventional guide catheter (CGC), and group 3—a similar thrombectomy procedure to group 2 but including the Lazarus Cover device. The primary endpoint was distal emboli quantified by the number and size of the clot debris.

Results The Cover-assisted stent retriever thrombectomy significantly reduced the generation of clot fragments >200 μm as compared with thrombectomy with a CGC, and was similar to the BGC group. Particle size distribution <200 μm was similar across the groups. All groups were associated with high rates of recanalization, with only one failed recanalization with partial clot retention after three passes in one experiment of stent retriever thrombectomy through a CGC. Use of the adjunctive Cover device did not prolong the procedure as compared with control groups.

Conclusions For a fragment-prone clot, Solitaire thrombectomy in conjunction with the Cover device may lower the risk of distal embolization and is comparable to BGC-protected embolectomy.

  • Thrombectomy
  • Stroke
  • Device

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  • Contributors J-YC: designed and performed the experiments, analyzed and processed the data, drafted the manuscript. ASP and MJG: designed the study, performed the experiments, revised the draft manuscript.

  • Funding This study was supported by Medtronic Neurovascular. The content is solely the responsibility of the authors, and does not necessarily represent the official views of Medtronic Neurovascular.

  • Competing interests MJG: has been a consultant on a fee per hour basis for Codman Neurovascular and Stryker Neurovascular; holds stock in InNeuroCo; and has received research support from the National Institutes of Health (NIH), Codman Neurovascular, Stryker Neurovascular, Microvention, Medtronic Neurovascular, Philips Healthcare, InNeuroCo, Neuronal Protection Systems, the Wyss Institute and Silk Road. ASP: holds stock in InNeuroCo, and has received research grants from Medtronic Neurovascular and Stryker Neurovascular.

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