In vivo comparison of braided (Accero) and laser-cut intracranial stents (Acclino, Credo): evaluation of vessel responses at subacute and mid-term follow-up in a rabbit model

Ruben Mühl-Benninghaus,Umut Yilmaz,Christoph Brochhausen,Stefanie Krajewski,Giorgio Cattaneo,Mara Kießling,Andreas Simgen,Wolfgang Reith,Toshiki Tomori,Philipp Dietrich

doi:10.1007/s10856-020-06460-z

Abstract

This study aimed to investigate in vivo two stent technologies, with particular emphasis on thrombogenicity and inflammatory vessel remodeling processes. The micro-stents tested in this study were developed for intracranial aneurysm treatment. In our study twelve, New Zealand white rabbits were divided into two groups: 18 laser-cut stents (LCS) and 18 braided stents (BS) were impanated without admiration of antiplatelet medication. Three stents were implanted into each animal in the common carotid artery, subclavian artery, and abdominal aorta. Digital subtraction angiography was performed before and after stent implantation and at follow-up for the visualization of occurring In-stent thromboembolism or stenosis. The Stents were explanted for histopathological examination at two different timepoints, after 3 and 28 days. Angiographically neither in-stent thrombosis nor stenosis for both groups was seen. There was a progressive increase in the vessel diameter, which was more pronounced for BS than for LCS. We detected a higher number of thrombi adherent to the foreign material on day 3 for BS. On day 3, the neointima was absent, whereas the complete formation observed was on day 28. There was no significant difference between both groups regarding the thickness of the neointima. The in vivo model of our study enabled the evaluation of blood and vessel reactions for two different stent technologies. Differences in vessel dimension and tissue around the stents were observed on day 28. Histological analysis on day 3 enabled the assessment of thrombotic reactions, representing an important complementary result in long-term studies.

Highlights

Stent-assisted coiling of wide-necked intracranial aneurysms aims to prevent coil prolapse into the parent vessel, enhancing vessel remodelling processes
A systematic comparison of two neurovascular stent technologies was performed in a new animal model in the absence of antiplatelet therapy, including two histological follow-up times
No stenosis or in-stent thrombosis was detected during follow-up for both stent types

Summary

Introduction

Stent-assisted coiling of wide-necked intracranial aneurysms aims to prevent coil prolapse into the parent vessel, enhancing vessel remodelling processes. This neurovascular technique has proven effective and safe in several studies, the presence of foreign material within the vessel lumen is associated with clinical complications. The divergent manufacturing processes result in consistent differences between both stent technologies, regarding stent elements (squared struts in LCS vs round wires in BS), stent profile (thicker in BS because of crossing wires at interconnecting points), and radial expansion force (high in both stents, depending on construction parameters and size) surface finishing is usually different in the two technologies [7]

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