Preclinical Evaluation of the Accero Stent: Flow Remodelling Effect on Aneurysm, Vessel Reaction and Side Branch Patency

Purpose It has been hypothesized that microstents which are used to prevent coil protrusion in the treatment of cerebral aneurysms may have flow diverting and therefore occlusive effects. In a rabbit elastase aneurysm model, we investigated the aneurysm occlusion rate and vessel reaction of a braided Accero stent prototype with porosity in the lower range of other available (non-flow-diverter) microstents. Methods Ten aneurysms were induced the right subclavian artery in New Zealand white rabbits and treated with the Accero stent prototype. In each subject, a second stent was implanted in the abdominal aorta to cover the origins of branch arteries. Angiographic follow-up and explantation of the devices and aneurysms for histological analysis were performed after 3 months (n = 5) and 6 months (n = 5). Results Grades I (< 50%) and II (> 50%) occlusion rates were observed in 9 (90%) and 1 (10%) of ten aneurysms treated with the stent device. The mean reduction in contrast filling at 6 months was 42.1% (p = .02). Neointima thickness was significantly higher in the subclavian artery than in the abdominal aorta after 3 (p = .03), whereas not after 6 months (p = .1). No cases of inadequate wall apposition, branch artery occlusion or stent thrombosis were observed. Conclusion The present study showed flow remodelling properties of the device prototype with progredient aneurysm occlusion. A larger in vivo study with induced aneurysm should be done to confirm these results.