Virmani R, Kolodgie F D, Dake M D, Silver J H, Jones R M, Jenkins M, Gillespie D L
Department of Cardiovascular Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000, USA.
J Vasc Interv Radiol. 1999 Apr;10(4):445-56. doi: 10.1016/s1051-0443(99)70064-3.
The authors assess a new ePTFE-nitinol stent for its long-term patency, healing, and properties of endothelialization.
Adult greyhounds (n = 18) underwent bilateral iliofemoral placement of an endoprosthesis (Hemobahn) consisting of a nitinol stent lined with an ultrathin expanded polytetrafluoroethylene (ePTFE) material. Histologic and quantitative morphometric analyses were performed on devices explanted at 2 weeks and 1, 3, 6, and 12 months. The source of endothelialization was examined in four additional devices modified by sealing either the proximal and distal ends or the entire graft with poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP), a nonporous laminate to prevent potential transgraft endothelial cell migration.
Device patency assessed with both intravascular ultrasound and histologic study showed minimal arterial stenosis, irrespective of implant duration. The neointima at less than 3 months consisted of fibrin and inflammatory infiltrate; at later time points, it was composed of mostly smooth muscle cells. Flow surfaces were more than 75% endothelialized by 3 months, which was nearly complete by 6 months. Modified endoprostheses entirely enveloped with FEP resulted in endothelialization of only the proximal and distal ends; the middle regions showed nonocclusive thrombi. Conversely, devices wrapped proximally and distally showed nearly complete endothelialization.
This ePTFE-nitinol endoprosthesis demonstrated long-term patency at up to 1 year after implantation and showed early and nearly complete endothelialization by 6 months. The design promoted rapid endothelialization of flow surfaces, particularly in the midregion of the device possibly by transgraft migration.
作者评估一种新型的聚四氟乙烯-镍钛诺支架的长期通畅性、愈合情况及内皮化特性。
18只成年灵缇犬接受双侧髂股动脉内假体（Hemobahn）植入，该假体由内衬超薄膨体聚四氟乙烯（ePTFE）材料的镍钛诺支架组成。对在2周、1个月、3个月、6个月和12个月时取出的装置进行组织学和定量形态学分析。另外四个装置通过用聚（四氟乙烯-共-六氟丙烯）（FEP）密封近端和远端或整个移植物进行改良，FEP是一种无孔层压板，以防止潜在的跨移植物内皮细胞迁移，从而研究内皮化的来源。
通过血管内超声和组织学研究评估的装置通畅性显示，无论植入时间长短，动脉狭窄程度均最小。3个月以内的新生内膜由纤维蛋白和炎性浸润组成；在后期时间点，主要由平滑肌细胞组成。到3个月时，血流表面内皮化超过75%，6个月时几乎完全内皮化。完全用FEP包裹的改良内假体仅导致近端和远端内皮化；中间区域显示非闭塞性血栓。相反，近端和远端包裹的装置显示几乎完全内皮化。
这种ePTFE-镍钛诺内假体在植入后长达1年的时间内显示出长期通畅性，并在6个月时显示出早期且几乎完全的内皮化。该设计促进了血流表面的快速内皮化，特别是在装置的中部区域，可能是通过跨移植物迁移实现的。
