Lee Jong Young, Cho Young Dae, Kang Hyun-Seung, Han Moon Hee
Department of Neurosurgery, Hallym University Gangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
J Korean Neurosurg Soc. 2020 Jan;63(1):34-44. doi: 10.3340/jkns.2019.0067. Epub 2019 Jul 15.
Despite widespread use of flow diverters (FDs) to treat aneurysms, the exact healing mechanism associated with FDs remains poorly understood. We aim to describe the healing process of aneurysms treated using FDs by demonstrating the histopathologic progression in a canine aneurysm model.
Twenty-one side wall aneurysms were created in common carotid artery of eight dogs and treated with two different FDs. Angiographic follow-ups were done immediately after placement of the device, 4 weeks and 12 weeks. At last follow-up, the aneurysm and the device-implanted parent artery were harvested.
Histopathologic findings of aneurysms at 4 weeks follow-up showed intra-aneurysm thrombus formation in laminating fashion, and neointimal thickening at the mid-segment of aneurysm. However, there are inhomogenous findings in aneurysms treated with the same type of FD showing same angiographic outcomes. At 12 weeks, aneurysms of complete and near-complete occlusion revealed markedly shrunken aneurysm filled with organized connective tissues with thin neointima. Aneurysms of incomplete occlusion at 12 weeks showed small amount of organized thrombus around fringe neck and large empty space with thick neointmal formation. Neointimal thickness and diameter stenosis was not significantly different between the groups of FD specification and follow-up period.
Intra-aneurysmal thrombus formation and organization seem to be an important factor for the complete occlusion of aneurysms treated using the FD. Neointimal formation could occur along the struts of the FD independently of intra-aneurysmal thrombus formation. However, neointimal formation could not solely lead to complete aneurysm healing.
尽管血流导向装置（FDs）在治疗动脉瘤方面已被广泛应用，但其确切的愈合机制仍不清楚。我们旨在通过展示犬动脉瘤模型中的组织病理学进展，来描述使用FDs治疗的动脉瘤的愈合过程。
在8只犬的颈总动脉上制造21个侧壁动脉瘤，并用两种不同的FDs进行治疗。在装置植入后、4周和12周时进行血管造影随访。在最后一次随访时，获取动脉瘤和植入装置的母动脉。
随访4周时动脉瘤的组织病理学结果显示，动脉瘤内血栓呈分层状形成，且动脉瘤中段有新生内膜增厚。然而，使用相同类型的FDs治疗且血管造影结果相同的动脉瘤存在不均匀的表现。在12周时，完全闭塞和近乎完全闭塞的动脉瘤显示，动脉瘤明显缩小，充满有组织的结缔组织，新生内膜较薄。12周时不完全闭塞的动脉瘤显示，边缘颈部周围有少量有组织的血栓，并有大的空隙和增厚的新生内膜形成。FD规格组和随访期组之间的新生内膜厚度和直径狭窄无显著差异。
动脉瘤内血栓形成和机化似乎是使用FDs治疗的动脉瘤完全闭塞的重要因素。新生内膜形成可独立于动脉瘤内血栓形成沿着FD的支柱发生。然而，新生内膜形成并不能单独导致动脉瘤完全愈合。
