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

Abstract

BACKGROUND AND PURPOSE: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.

The Varying Porosity of Braided Self-Expanding Stents and Flow Diverters: An Experimental Study

“…We have previously tested both high-porosity braided selfexpanding stents and flow diverters in wide-neck, bifurcation, and giant aneurysm models, and failures have occurred, particularly when devices were deployed in a curved configuration. [1][2][3] Device deformations and subsequent heterogeneity in device porosity were frequent and sometimes quite substantial. [1][2][3] When in vivo porosities of the portion of the devices bridging the aneurysm ostium were measured, it became clear that these were strongly influenced by the discrepancy in diameter between the parent artery and the portion of the device that was free to expand at the level of the aneurysm neck.…”

“…[1][2][3] Device deformations and subsequent heterogeneity in device porosity were frequent and sometimes quite substantial. [1][2][3] When in vivo porosities of the portion of the devices bridging the aneurysm ostium were measured, it became clear that these were strongly influenced by the discrepancy in diameter between the parent artery and the portion of the device that was free to expand at the level of the aneurysm neck. This phenomenon could perhaps explain some failures of flow diversion and the lack of neointima formation at the neck of treated aneurysms, with persisting aneurysm filling despite FD treatment.…”

“…We have previously shown in animal models that as these devices adapt to the constraints of local anatomy, the ensuing deformations can lead to substantial variations in device porosity between cases treated with the same device as well as wide variations in porosity along the different segments of the same device. 1,2 Ideally, the aim of a flow-diversion treatment strategy is to form a tubular conduit of optimal porosity that will normalize linear flow, reconstruct the parent vessel, and effectively occlude the aneurysm while preserving arterial branches and perforators. Because the amount of "metallic coverage" of aneurysm and branch ostia may affect treatment safety and efficacy, it is desirable to accurately predict when and to what extent these deformations will occur and how these will influence device porosity.…”

Tapered flow diverters in the treatment of intracranial aneurysms

“…Focal zones of low porosity and residual flow specifically occur in curved segments or wide-neck aneurysms due to the deformation of the FD (8,13). This deformation at the TZ is a potential cause of failure of flow diversion in wide-neck curved and/or endwall aneurysms (2,(6)(7)(8)13). …”

Thrombosis Heralding Aneurysmal Rupture: An Exploration of Potential Mechanisms in a Novel Giant Swine Aneurysm Model

“…7,8 Thrombusprecipitating rupture has also been implicated in abdominal aortic aneurysms. [9][10][11][12] However, because thrombosis followed by organization and neointimal closure of the neck is required for successful occlusion of aneurysms by endovascular embolization, 11,[13][14][15][16][17][18] there must be additional factors to account for thrombosis leading to rupture rather than occlusion. Such discriminating factors have not been explored experimentally, to our knowledge.…”