Service de Neuroradiologie, CHRU Strasbourg, Strasbourg, France.
Neuroradiology. 2013 Jan;55(1):85-92. doi: 10.1007/s00234-012-1082-0. Epub 2012 Aug 16.
High-porosity (HP) and flow-diverting (FD) stents are increasingly used to treat intracranial aneurysms. In vivo device deformations and their impact on the porosity of the segment of device lying over the aneurysm neck remain inadequately characterized.
Porosities of different braided FDs were studied in straight and 90° curved glass tubes. In vivo, 11 experimental lateral wall aneurysms were treated with FD (n = 7) or HP (n = 4) stents. At 3 months, the segment of FDs and HP stents over the aneurysm neck was analyzed, paying attention to changes in device diameter, metallic porosity, and neointimal closure of pores over the aneurysm or branch ostia. Device deformations were reproduced with benchtop experiments.
In 90° curved tubes, FD porosity was higher (P = 0.025) and pore density was lower (P = 0.01) on convex compared to concave surfaces, but variations remained within 5-10 %. After in vivo deployment, a spindle-shaped deformation of FDs occurred, with focal expansion at the level of the aneurysm neck (P = 0.004). This deformation translated into an accordion-like distribution of stent struts across the aneurysm neck, where porosity was not uniform. The midsection of the aneurysm ostium had more metal coverage than adjacent ostial areas (P = 0.002). Mean porosity over the aneurysm neck was 78 ± 9.4 and 32.6 ± 12.1 % for HP and FD stents, respectively (P = 0.008), decreasing to 13.0 ± 10.1 and 1.4 ± 0.6 % (P = 0.022) following neointimal coverage, respectively. Spindle-shaped deformations and accordion effects were reproduced with benchtop manipulations; fluctuations in porosity and diameter changes correlated closely (R = 0.81; P = 0.005).
Alterations in porosity may occur following in vivo implantation.
高孔隙率（HP）和血流导向（FD）支架越来越多地用于治疗颅内动脉瘤。在体内，装置的变形及其对动脉瘤颈部上方装置段的孔隙率的影响仍未得到充分描述。
研究了不同编织 FD 的孔隙率在直玻璃管和 90°弯曲玻璃管中的变化。在体内，用 FD（n=7）或 HP（n=4）支架治疗 11 例实验性侧壁动脉瘤。3 个月时，分析了 FD 和 HP 支架在动脉瘤颈部上方的节段，注意装置直径、金属孔隙率以及动脉瘤或分支口孔隙的新生内膜覆盖的变化。用台式实验再现了装置的变形。
在 90°弯曲管中，FD 的孔隙率（P=0.025）更高，凸面的孔密度（P=0.01）更低，但变化仍在 5-10%范围内。FD 在体内释放后，会发生纺锤形变形，在动脉瘤颈部水平出现焦点扩张（P=0.004）。这种变形导致支架支柱在动脉瘤颈部呈手风琴状分布，孔隙率不均匀。动脉瘤口的中部比相邻的口区域有更多的金属覆盖（P=0.002）。FD 和 HP 支架在动脉瘤颈部的平均孔隙率分别为 78±9.4%和 32.6±12.1%（P=0.008），新生内膜覆盖后分别降至 13.0±10.1%和 1.4±0.6%（P=0.022）。通过台式操作再现了纺锤形变形和手风琴效应；孔隙率的波动与直径变化密切相关（R=0.81；P=0.005）。
在体内植入后，孔隙率可能会发生变化。
