Flow diverters can occlude aneurysms and preserve arterial branches: a new experimental model

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.

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 (n = 4), 2 overlapping HP stents (n = 4), or an FD (n = 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.

FDs led to better angiographic occlusion scores compared with HP stents (P = .026). FDs were significantly more likely to occlude the aneurysm than the branch (P = .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 (P = .039). Angiographic occlusion correlated with metallic porosity and neointimal tissue coverage (Spearman ρ = -0.81; P = .001).

In this study, flow diverters occluded lateral wall aneurysms more readily than branches. Metal device porosity strongly influenced the occlusion rate.