Correlation of aneurysm occlusion with actual metal coverage at neck after implantation of flow-diverting stent in rabbit models

A remarkable curing rate has been achieved in the treatment of intracranial intractable aneurysms by using flow-diverting stents (FDS). An appropriate metal coverage (MC) of this device influences the hemodynamics of aneurysm significantly but little to branches in vitro. The MC changes after elongation or compression and the actual changes are still unknown in vivo. In this paper, we analyzed the correlation of aneurysm occlusion with actual MC after implantation of FDS in rabbit models. FDS was implanted across the necks of 22 elastase-induced aneurysms in rabbits. Animals were performed for angiography at 4 weeks and sacrificed at 3 months after angiography for pathology. Tissue was explanted with stent for micro-computed tomography scan, and local shape of stent at neck was reconstructed. Actual MC at neck was calculated, and the correlations of aneurysm occlusion with effective factors were analyzed. Greater than 95% angiographic aneurysm occlusion rates for the FDS, which covered the neck of aneurysms, were 61.9% at 4 weeks and 57.9% by angiography at 3 months. Aneurysm occlusion was positively correlated with local MC of stent at neck (r (s) = 0.486; P = 0.026). A 35% actual MC at the neck predicted greater than 95% angiographic aneurysm occlusion with a specificity of 100% and sensitivity of 53.8%. Aneurysm occlusion was positively correlated with local MC of stent at the neck. The FDS with 35% MC can predict greater than 95% angiographic aneurysm occlusion.