title: Peri-strut low-intensity areas in optical coherence tomography correlate with peri-strut inflammation and neointimal proliferation: an in-vivo correlation study in the familial hypercholesterolemic coronary swine model of in-stent restenosis.
abstract: BACKGROUND
  Peri-strut low-intensity area (PLI) is a common imaging finding during the evaluation of in-stent neointima using optical coherence tomography (OCT). We aimed to determine the biological significance of PLI by comparing in-vivo OCT images with the corresponding histological sections obtained from the familial hypercholesterolemic swine model of coronary stenosis.
  
  
  METHODS
  A total of 26 coronary vessels of nine familial hypercholesterolemic swine were injured with 30% balloon overstretch and then immediately followed by everolimus eluting or bare metal stent placement at 20% overstretch. At 30 days, all stented vessels were subjected to in-vivo OCT analysis and were harvested for histological evaluation. For OCT analysis, stent cross-sections (three per stent) were categorized into presence (PLI+) or absence (PLI-) of PLI. In histology, inflammation and fibrin deposition were scored semiquantitatively from 0 (none) to 3 (severe).
  
  
  RESULTS
  PLI was found in 64.9% of stent sections. Peri-strut inflammation was more frequently observed in OCT sections PLI (+) compared with PLI (-) (56.0 vs. 7.4%, P=0.01). In contrast, peri-strut fibrin deposits was similar in both groups (PLI+=58.0% vs. PLI-=59.3%, P=0.94). Histological neointimal thickness was significantly higher in PLI (+) sections (mean±SE: 0.68±0.06 vs. 0.34±0.02 mm; P<0.01), yielding a higher percent area stenosis compared with PLI (-) (mean±SE: 59.0±4.4 vs. 34.1±2.2%, P<0.01). The PLI diagnostic sensitivity and specificity for inflammation were 80 and 76.1%, respectively (>56% PLI, area under the curve=0.86, P<0.01), whereas for fibrin deposition, the sensitivity and specificity were 42.2 and 76.1%, respectively (area under the curve=0.56, P=NS). Area under the receiver operating characteristic curve was significantly higher for identifying inflammation than fibrin (0.86 vs. 0.56, P<0.01). The severity of PLI correlated with the neointimal thickness when assessed by OCT (R=0.79, P<0.001).
  
  
  CONCLUSIONS
  The presence of PLI in OCT correlates with neointimal thickness and appears to have a diagnostic value in the recognition of peri-strut inflammation, therefore possibly serving as a surrogate for in-vivo assessment of stent efficacy.
authors.affiliation: aJack H. Skirball Center for Cardiovascular Research, Cardiovascular Research Foundation, Orangeburg, New York bMemorial Hospital of Rhode Island, Alpert Medical School of Brown University, Pawtucket, Rhode Island cDepartment of Preclinical Sciences, Boston Scientific Corporation, Natick, Massachusetts, USA.
authors.forename: Armando
authors.initials: A
authors.lastname: Tellez
authors.forename: Maxwell E
authors.initials: ME
authors.lastname: Afari
authors.forename: Piotr P
authors.initials: PP
authors.lastname: Buszman
authors.forename: Paul
authors.initials: P
authors.lastname: Seifert
authors.forename: Yanping
authors.initials: Y
authors.lastname: Cheng
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Milewski
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: McGregor
authors.forename: Javier A
authors.initials: JA
authors.lastname: Garza
authors.forename: Mary B
authors.initials: MB
authors.lastname: Roberts
authors.forename: Geng Hua
authors.initials: GH
authors.lastname: Yi
authors.forename: Greg L
authors.initials: GL
authors.lastname: Kaluza
authors.forename: Juan F
authors.initials: JF
authors.lastname: Granada
mesh_terms: D000818:Animals; D003324:Coronary Artery Disease; D023903:Coronary Restenosis / Q000378:metabolism / Q000473:pathology*; D003331:Coronary Vessels / Q000378:metabolism / Q000473:pathology*; D004195:Disease Models, Animal; D054855:Drug-Eluting Stents; D005337:Fibrin / Q000378:metabolism; D006083:Graft Occlusion, Vascular / Q000378:metabolism / Q000473:pathology*; D006938:Hyperlipoproteinemia Type II; D006965:Hyperplasia; D007249:Inflammation / Q000378:metabolism / Q000473:pathology*; D008297:Male; D058426:Neointima / Q000378:metabolism / Q000473:pathology*; D015607:Stents; D013552:Swine; D041623:Tomography, Optical Coherence
chemical_list: D005337:Fibrin