Flow Diverters Can Occlude Aneurysms and Preserve Arterial Branches: A New Experimental Model

Abstract

<h3>BACKGROUND AND PURPOSE:</h3> FDs are new intracranial stents designed to occlude aneurysms while preserving flow to jailed arterial branches. We tested this fundamental principle in a new aneurysm model. <h3>MATERIALS AND METHODS:</h3> Canine lateral wall aneurysms, featuring a branch located immediately opposite the aneurysm, were created in 16 animals to study the effects on aneurysm or branch occlusion using single HP stents (<i>n</i> = 4), 2 overlapping HP stents (<i>n</i> = 4), or an FD (<i>n</i> = 8). Two other animals, in which an efferent arterial branch was anastomosed to the aneurysm fundus, were also treated with FDs. Angiographic results after deployment, at 2 weeks, and at 3 months were scored using an ordinal scale. The metal porosity of the FSS and the amount of FSS neointima formation was determined by postmortem photography. <h3>RESULTS:</h3> FDs led to better angiographic occlusion scores compared with HP stents (<i>P</i> = .026). FDs were significantly more likely to occlude the aneurysm than the branch (<i>P</i> = .01). When the branch was switched to originate from the aneurysm fundus, the FDs became ineffective (0/2). Neointimal closure of the aneurysm ostium was significantly better with FDs than with single or double HP stents (<i>P</i> = .039). Angiographic occlusion correlated with metallic porosity and neointimal tissue coverage (Spearman ρ = −0.81; <i>P</i> = .001). <h3>CONCLUSIONS:</h3> In this study, flow diverters occluded lateral wall aneurysms more readily than branches. Metal device porosity strongly influenced the occlusion rate.