Purpose The Woven Endobridge (WEB) device (Sequent Medical, Inc., Aliso Viejo, CA) is an intrasaccular flow-disruption device. The purpose of this study was to evaluate the acute and chronic performance of new generation WEB devices using rabbit aneurysm model.
Materials and methods Six Enhanced Visualization (EV) WEB-DL (Dual Layer with barrel configuration); six EV WEB-SL (Single Layer with barrel configuration); and six EV WEB-SLS (Single Layer Sphere with spherical configuration) were deployed in 18 elastase-inducedaneurysms in the rabbits and followedfor 12 months. Degrees of aneurysm occlusion immediately after treatment and before sacrifice were graded on a 4 point scale from digital subtraction angiography (DSA): Grade 1, complete flow cessation; Grade 2, near complete flow cessation; Grade 3, incomplete flow cessation; Grade 4, fully patent aneurysm. Comparison of aneurysm occlusion between acute and chronic time points was performed using a 3 point scale (stable occlusion, progressive occlusion, or recanalization). Two shapes of aneurysms were defined: Type I, spherical; Type II, cylinder-like. All aneurysms were harvested for histologic analysis.
Results Four spherical and 14 cylinder-like aneurysms were identified. Grade 3 or 4 occlusion was shown in all the three groups acutely. Before sacrifice, Grade 1 (n = 3) and Grade 2 (n = 3) were shown in DL group; Grade 1 (n = 1), Grade 2 (n = 2) and Grade 3 (n = 3) were indicated in SL group; Grade 1 (n = 1), Grade 2 (n = 1), Grade 3 (n = 3), and Grade 4 (n = 1) were shown in SLS group, respectively. Sixteen (89%, 16/18) aneurysms showed progressive occlusion. Aneurysm recanalization was found in one (6%, 1/18) aneurysm of the SLS group. One (6%, 1/18) aneurysm remained stable in SLS group. Extent of occlusion was greater in one spherical aneurysm treated with SLS device by comparison with other spherical aneurysms treated with DL or SL device. Histologic features included unorganized blood clot or organized loose connective tissue filling the aneurysm sac and endothelialized neointima or incompletely organized thrombus across the neck interface. Inflammation within aneurysm lumen was absent or minimal (as localized, patchy, chronic inflammatory foci) (See attached Figure 1).
Conclusion Progressive aneurysm occlusion can be achieved using all the three types of devices. Based on the good healing achieved using SLS for spherical aneurysm, SLS may be helpful to occlude narrow neck (spherical) aneurysms.
Disclosures Y. Ding: None. D. Dai: None. D. Schroeder: None. R. Kadirvel: None. D. Kallmes: None.
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