title: Short- and long-term histopathologic evaluation of stenting using a self-expanding nitinol stent in pig carotid and iliac arteries.
abstract: Stenting is increasingly being used to treat carotid artery disease. However, complications including distal embolization, stent thrombosis, stent collapse from external compression, the need for high-pressure inflation with increased neointimal response, or balloon rupture during stent expansion and stent loss are all potential problems and of concern. To address each of these specific concerns, a new stent was designed, which is self-expandable, made of nitinol, with temperature-dependent superelastic properties, and with high vessel wall surface coverage. Since this device has a number of novel characteristics, we aimed to assess the short- and long-term histopathologic response in pig carotid and iliac arteries. Single stents were deployed in pig carotid and iliac arteries after overstretch balloon injury. Angiograms were performed pre- and poststenting and prior to sacrifice. Intravascular ultrasound was used before implantation to determine vessel size. Vessels were examined histologically at 1 month (n = 6) and 6 months (n = 6) for morphometric analysis, hemorrhage and thrombus, endothelialization, and inflammatory and fibrotic responses. There was a 100% angiographic success rate at implantation. In one case, it was determined histologically that a single stent was implanted in a dissection plane of a pig's left iliac artery and was occluded by organized thrombus, with the true lumen being patent. At 6-month follow-up, this was the only evidence of a single stent occlusion, with flow adjacent to the stent in the true lumen. In the other vessels, the stents showed good vessel wall-stent apposition and the lumens were patent with a concentric and thin neointima. Inflammatory cells were rare and there were no mural thrombi. Coverage of the vessel wall by endothelial-like cells was complete at 1 month. The novel nitinol EndoStent appears to have favorable biocompatibility with minimal thrombus deposition or inflammatory response, and its use is feasible for clinical application in carotid and iliac arteries.
authors.affiliation: Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia, USA.
authors.forename: S
authors.initials: S
authors.lastname: Verheye
authors.forename: M Y
authors.initials: MY
authors.lastname: Salame
authors.forename: K A
authors.initials: KA
authors.lastname: Robinson
authors.forename: M J
authors.initials: MJ
authors.lastname: Post
authors.forename: J P
authors.initials: JP
authors.lastname: Carrozza
authors.forename: D S
authors.initials: DS
authors.lastname: Baim
authors.forename: U
authors.initials: U
authors.lastname: Sigwart
authors.forename: S B
authors.initials: SB
authors.lastname: King
authors.forename: N A
authors.initials: NA
authors.lastname: Chronos
mesh_terms: D000497:Alloys; D000818:Animals; D001157:Arterial Occlusive Diseases / Q000601:surgery; D001672:Biocompatible Materials; D019917:Blood Vessel Prosthesis Implantation; D002339:Carotid Arteries / Q000473:pathology / Q000601:surgery*; D004195:Disease Models, Animal; D005500:Follow-Up Studies; D007083:Iliac Artery / Q000473:pathology / Q000601:surgery*; D011474:Prosthesis Design; D015607:Stents; D013552:Swine
chemical_list: D000497:Alloys; D001672:Biocompatible Materials; C013616:nitinol