Experimental Direct Measurement of Clot-Capturing Ability of Stent Retrievers

Abstract

Background: Stent retrievers (SRs) can be used to perform mechanical thrombectomy for the treatment of acute major arterial occlusion. Recanalization is faster, and outcomes are better with treatment involving these devices than with internal treatment. Although several SRs are available, their clot-capturing abilities are unclear. Therefore in the present study, we numerically evaluated the clot-capturing abilities of SRs in an experimental vascular model.

Methods: A sham clot (urethane foam) was fixed with sutures at the middle of a vascular model (polyvinyl chloride tube). One end of the tube was connected to a measuring instrument. From the other end, an SR was inserted and deployed over the sham clot. The delivery wire of the stent was then withdrawn at a constant velocity using an automatic withdrawal machine. The maximum frictional force before the stent left the clot was measured. Five stents (Trevo ProVue [2 sizes], Revive, and Solitaire [2 sizes]) and three stent-deployment techniques (standard, push-and-fluff, and wire-push techniques) were evaluated.

Results: The clot-capturing ability (maximum withdrawing force [N: newton]) was greater for large-diameter stents than for small-diameter stents (mean 0.39 ± 0.11 vs. 0.56 ± 0.18). For Trevo and Revive, the clot-capturing ability was highest with the push and fluff technique (mean 0.43 ± 0.05). For Solitaire, the ability was the highest with the simple wire-push technique (mean 0.705 ± 0.16).

Conclusions: We successfully numerically evaluated the clot-capturing abilities of SRs. The clot-capturing ability differed among SRs and among stent-deployment techniques.

Keywords: Acute ischemic stroke; Endovascular treatment; Experiment; Stent clot retriever; Technique.