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Title: Late Stent Expansion and Neointimal Proliferation of Oversized Nitinol Stents in Peripheral Arteries

For peripheral endovascular intervention, self-expanding (SE) stents are commonly oversized in relation to target arteries to assure optimal wall apposition and prevent migration. However, the consequences of oversizing have not been well studied. The purpose of this study was to examine the effects of SE stent oversizing (OS) with respect to the kinetics of late stent expansion and the long-term histological effects of OS. Pairs of overlapped 8 x 28-mm Nitinol SE stents were implanted into the iliofemoral arteries of 14 Yucatan swine. Due to variations in target artery size, the stent-to-artery ratio ranged from 1.2:1 to 1.9:1. Lumen and stent diameters were assessed by quantitative angiography at the time of implantation. Following angiographic assessment at 6 months, stented arteries were perfusion-fixed, sectioned, and stained for histological analysis. Immediately following implantation, the stents were found to be expanded to a range of 4.7-7.1 mm, largely conforming to the diameter of the recipient target artery. The stents continued to expand over time, however, and all stents had enlarged to nearly their 8-mm nominal diameter by 6 months. The histological effects of OS were profound, with marked increases in injury and luminal area stenosis, including a statistically significant linear correlation between stent-to-arterymore » ratio and area stenosis. In this experimental model of peripheral endovascular intervention, oversized Nitinol SE stents are constrained by their target artery diameter upon implantation but expand to their nominal diameter within 6 months. Severe OS (stent-to-artery ratio >1.4:1) results in a profound long-term histological response including exuberant neointimal proliferation and luminal stenosis.« less
Authors:
;  [1] ; ; ;  [2] ;  [1]
  1. Abbott Vascular (United States)
  2. CVPath (United States)
Publication Date:
OSTI Identifier:
21428490
Resource Type:
Journal Article
Resource Relation:
Journal Name: Cardiovascular and Interventional Radiology; Journal Volume: 32; Journal Issue: 4; Other Information: DOI: 10.1007/s00270-009-9601-z; Copyright (c) 2009 Springer Science+Business Media, LLC and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ARTERIES; BIOMEDICAL RADIOGRAPHY; EXPANSION; NICKEL ALLOYS; PHENOBARBITAL; PROLIFERATION; SWINE; TITANIUM ALLOYS; TUBES ALLOYS; ANESTHETICS; ANIMALS; ANTICONVULSANTS; AZINES; BARBITURATES; BLOOD VESSELS; BODY; CARDIOVASCULAR SYSTEM; CENTRAL NERVOUS SYSTEM AGENTS; CENTRAL NERVOUS SYSTEM DEPRESSANTS; DIAGNOSTIC TECHNIQUES; DOMESTIC ANIMALS; DRUGS; HETEROCYCLIC COMPOUNDS; HYPNOTICS AND SEDATIVES; MAMMALS; MEDICINE; NUCLEAR MEDICINE; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; ORGANIC OXYGEN COMPOUNDS; ORGANS; PYRIMIDINES; RADIOLOGY; TRANSITION ELEMENT ALLOYS; VERTEBRATES