Article Text
Abstract
Background Five randomized controlled trials recently appeared in the literature demonstrating that early mechanical thrombectomy in patients with acute ischemic stroke is significantly related to an improved outcome. Stent retrievers are accepted as the most effective devices for intracranial thrombectomy.
Objective To analyze the mechanical properties of stent retrievers, their behavior during retrieval, and interaction with different clots and to identify device features that might correlate with the effectiveness of thrombus removal.
Materials and methods All stent retrievers available in France up to June 2015 were evaluated by mechanical and functional tests aimed at investigating the variation of their radial force and their behavior during retrieval. Devices were also tested during in vitro thrombectomies using white and red experimental thrombi produced with human blood. Functional tests and in vitro thrombectomies were conducted using a rigid 3D printed vascular model.
Results Mechanical tests showed a variation in radial force during retrieval for each stent. A constant radial force during retrieval was related to continuous cohesion over the vessel wall and a higher rate of clot removal efficacy. All stent retrievers failed when interacting with white large thrombi (diameter ≥6 mm).
Conclusions None of the tested devices were effective in removing white clots of large diameter (≥6 mm). Constant radial force during retrieval allows constant cohesion to the vessel wall and pressure over the clot; such features allow for a higher rate of clot removal.
- Stroke
- Thrombectomy
- Stent
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Footnotes
Contributors All authors contributed to planning the research and conducting the experiments. PM and FJ edited the manuscript.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Competing interests AB unrelated: consultancy: Covidien (consultant for ev3), Stryker; grants/grants pending: Covidien. VC: consultancy: Balt, Codman Neuro-DePuy Synthes, Stryker, MicroVention; payment for lectures (including service on speakers bureaus): Stryker, Balt; payment for development of educational presentations: Covidien.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement We are agreeable to sharing unpublished data with readers if requested.