title: Acute Thrombogenicity of a Durable Polymer Everolimus-Eluting Stent Relative to Contemporary Drug-Eluting Stents With Biodegradable Polymer Coatings Assessed Ex Vivo in a Swine Shunt Model.
abstract: OBJECTIVE
  This study sought to evaluate whether the permanent fluoropolymer-coated Xience Xpedition everolimus-eluting stent (Xience-EES) exhibits lower acute thrombogenicity compared with contemporary drug-eluting stents (DES) with biodegradable polymer coatings in an acute swine shunt model.
  
  
  BACKGROUND
  Previous pre-clinical and clinical experience suggests that several factors may influence the predisposition for acute thrombus formation of polymer-coated DES, including stent design and the polymer coating technology. It remains unclear whether relevant differences exist with respect to acute thrombogenicity, particularly between current commercial stent designs using permanent polymers and those using biodegradable polymers.
  
  
  METHODS
  An ex vivo carotid to jugular arteriovenous porcine shunt model involving a test circuit of 3 in-line stents, was used to test acute thrombogenicity, where Xience-EES (n = 24) was compared with 4 CE-marked DES with biodegradable polymer coatings (BioMatrix Flex, Synergy, Nobori, and Orsiro [n = 6 each]). After 1 h of circulation, platelet aggregation in whole mount stents was evaluated by confocal microscopy with immunofluorescent staining against dual platelet markers (CD61/CD42b) along with scanning electron microscopy.
  
  
  RESULTS
  Xience-EES showed the least percentage of thrombus-occupied area as compared with the biodegradable polymer-coated DES, with a significant difference compared with BioMatrix Flex and Synergy (mean differences: [BioMatrix Flex: 15.54, 95% confidence interval [CI]: 11.34 to 19.75, p < 0.001; Synergy: 8.64, 95% CI: 4.43 to 12.84, p < 0.001; Nobori: 4.22, 95% CI: -0.06 to 8.49, p = 0.055; Orsiro: 2.95, 95% CI: -1.26 to 7.15, p = 0.286). The number of cell nuclei on strut surfaces was also the least in Xience-EES, with a significant difference relative to BioMatrix Flex, Nobori, and Orsiro (mean ratios: BioMatrix Flex: 4.73, 95% CI: 2.46 to 9.08, p < 0.001; Synergy: 1.44, 95% CI: 0.75 to 2.76, p = 0.51; Nobori: 5.97, 95% CI: 3.11 to 11.44, p < 0.001; Orsiro: 5.16, 95% CI: 2.69 to 9.91, p < 0.001).
  
  
  CONCLUSIONS
  Xience-EES's overall design confers acute thromboresistance relative to contemporary DES with biodegradable coatings, with less platelet aggregation versus BioMatrix Flex and Synergy, and less inflammatory cell attachment versus BioMatrix Flex, Nobori, and Orsiro, in an ex vivo swine shunt model, which lends support to reported clinical findings of lower early stent thrombosis.
authors: CVPath Institute, Inc., Gaithersburg, Maryland.
authors: Fumiyuki
authors: F
authors: Otsuka
authors: CVPath Institute, Inc., Gaithersburg, Maryland.
authors: Qi
authors: Q
authors: Cheng
authors: CVPath Institute, Inc., Gaithersburg, Maryland.
authors: Kazuyuki
authors: K
authors: Yahagi
authors: CVPath Institute, Inc., Gaithersburg, Maryland.
authors: Eduardo
authors: E
authors: Acampado
authors: Abbott Vascular, Santa Clara, California.
authors: Alexander
authors: A
authors: Sheehy
authors: CVPath Institute, Inc., Gaithersburg, Maryland.
authors: Saami K
authors: SK
authors: Yazdani
authors: CVPath Institute, Inc., Gaithersburg, Maryland.
authors: Kenichi
authors: K
authors: Sakakura
authors: CVPath Institute, Inc., Gaithersburg, Maryland.
authors: Kristina
authors: K
authors: Euller
authors: Abbott Vascular, Santa Clara, California.
authors: Laura E L
authors: LEL
authors: Perkins
authors: CVPath Institute, Inc., Gaithersburg, Maryland.
authors: Frank D
authors: FD
authors: Kolodgie
authors: CVPath Institute, Inc., Gaithersburg, Maryland.
authors: Renu
authors: R
authors: Virmani
authors: CVPath Institute, Inc., Gaithersburg, Maryland. Electronic address: mjoner@cvpath.org.
authors: Michael
authors: M
authors: Joner
mesh_terms: D000208:Acute Disease; D000818:Animals; D001777:Blood Coagulation; D002317:Cardiovascular Agents / Q000008:administration & dosage*; D020099:Coated Materials, Biocompatible; D054855:Drug-Eluting Stents; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation*; D000068338:Everolimus / Q000008:administration & dosage*; D007249:Inflammation / Q000097:blood / Q000209:etiology / Q000517:prevention & control; D008422:Materials Testing; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D010974:Platelet Aggregation; D011108:Polymers / Q000737:chemistry*; D011474:Prosthesis Design; D013552:Swine; D013927:Thrombosis / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D013997:Time Factors
chemical_list: D002317:Cardiovascular Agents; D020099:Coated Materials, Biocompatible; D011108:Polymers; D000068338:Everolimus
keywords: coronary disease; pathology; stents; thrombosis