Wakhloo A K, Schellhammer F, de Vries J, Haberstroh J, Schumacher M
Department of Neuroradiology, University of Freiburg, Federal Republic of Germany.
AJNR Am J Neuroradiol. 1994 Mar;15(3):493-502.
To assess the efficacy of metal stents for the treatment of different forms and sizes of carotid aneurysms.
A total of 14 experimentally constructed aneurysms in dogs were treated with transfemorally placed balloon-expandable tantalum and self-expanding nitinol stents.
In 10 cases, stenting produced either immediate complete occlusion of the aneurysm (n = 7) or complete delayed thrombosis after 7 to 10 days (n = 3). In two cases treated with balloon-expandable tantalum endoprostheses, repeated angiography showed a persistent aneurysmal neck with a diameter of 1 mm. No incompletely occluded aneurysms were visible after implantation of nitinol stents. Nine-month angiographic follow-up revealed maximal stenosis of the stented vessel segment of up to 40% after placement of tantalum endoprostheses. However, no more than 15% stenosis followed the deployment of nitinol stents. Histologic examination confirmed these findings. Significantly greater intimal fibrocellular tissue growth surrounded tantalum filaments than nitinol filaments, which were covered with a smooth, thin neointimal layer. In two carotid arteries a subtotal and total occlusion of the parent vessel occurred after the insertion of a tantalum and nitinol stent, respectively. No recanalization of completely occluded aneurysms or delayed migration of a stent was observed.
Porous, tubular self-expanding nitinol stents may become the treatment of choice for broad-based and fusiform aneurysms of the internal carotid artery. However, blood flow dynamics of the aneurysms must be studied carefully in order to select an appropriate mesh size for complete occlusion while preserving the parent vessel. Improvements in the introducing system, stent material, and stent shape are required for simple implantation and reduction of intimal hyperplasia.
评估金属支架治疗不同形态和大小颈动脉动脉瘤的疗效。
对14只实验构建的犬颈动脉动脉瘤经股动脉置入球囊扩张钽支架和自膨式镍钛合金支架进行治疗。
10例中，支架置入后动脉瘤立即完全闭塞（7例）或在7至10天后完全延迟血栓形成（3例）。在用球囊扩张钽内支架治疗的2例中，重复血管造影显示动脉瘤颈部持续存在，直径为1毫米。植入镍钛合金支架后未见不完全闭塞的动脉瘤。9个月的血管造影随访显示，钽内支架置入后，支架血管段最大狭窄达40%。然而，镍钛合金支架置入后狭窄不超过15%。组织学检查证实了这些发现。钽丝周围内膜纤维细胞组织生长明显多于镍钛丝，镍钛丝覆盖有光滑、薄的新生内膜层。分别在插入钽支架和镍钛合金支架后，两条颈动脉主干血管发生了次全闭塞和完全闭塞。未观察到完全闭塞的动脉瘤再通或支架延迟移位。
多孔管状自膨式镍钛合金支架可能成为颈内动脉宽基底和梭形动脉瘤的首选治疗方法。然而，必须仔细研究动脉瘤的血流动力学，以便选择合适的网眼尺寸以实现完全闭塞，同时保留主干血管。为了便于植入和减少内膜增生，需要改进导入系统、支架材料和支架形状。
