title: Drug-eluting stents in bifurcations: bench study of strut deformation and coating lesions.
abstract: BACKGROUND
  The use of a drug-eluting stent (DES) has strongly limited the incidence of in-stent restenosis in bifurcation lesions; nevertheless, restenosis still remains a problem at the origin of the bifurcation side branch. The aim of this study is to analyze the consequences of the kissing postdilatation technique on 5 DESs, using microfocus x-ray computerized tomography and scanning electron microscopy.
  
  
  RESULTS
  Five different DESs (Cypher, Cypher Select, Endeavor, Taxus Express, and Taxus Liberté) were deployed using kissing postdilatation protocols in a bench-top model. For all types of DES, microfocus x-ray computerized tomography analysis showed that (1) kissing postdilatation of the stent by 2 coaxial balloons caused elliptic deformation in the proximal segment and (2) kissing postdilatation technique reduced the ratio of potential metal to artery (manufacturer's data/calculated ratio [%]: Cypher, 12.7/8.8; Cypher Select, 13.5/10.2; Endeavor, 19.0/13.3; Taxus Express, 20.5/4.7; Taxus Liberté, 17.9/12.5) and the potential drug application to area in the proximal segment, including the ostial struts (struts adjacent to and lying around the side branch ostium) (manufacturer's data/calculated drug application [microg/mm(2)]: Cypher, 1.4/1.0; Cypher Select, 1.4/1.1; Endeavor, 1.6/1.1; Taxus Express, 1.0/0.7; Taxus Liberté, 1.0/0.7). Scanning electron microscopy analysis showed a significantly greater coating damage to the ostial struts in all stents evaluated (P<0.05).
  
  
  CONCLUSIONS
  Commercially available DESs subjected to simultaneous kissing balloon postdilatation in an unconstrained model may contribute to side branch ostial restenosis by proximal segment elliptic deformation and damage to the polymer coating.
authors.affiliation: INSERM UMR915, l'institut du thorax, 8 quai Moncousu, Nantes cedex 1, France. patrice.guerin@chu-nantes.fr
authors.forename: Patrice
authors.initials: P
authors.lastname: Guérin
authors.forename: Paul
authors.initials: P
authors.lastname: Pilet
authors.forename: Gérard
authors.initials: G
authors.lastname: Finet
authors.forename: Yann
authors.initials: Y
authors.lastname: Gouëffic
authors.forename: Jean Michel
authors.initials: JM
authors.lastname: N'Guyen
authors.forename: Dominique
authors.initials: D
authors.lastname: Crochet
authors.forename: Isabelle
authors.initials: I
authors.lastname: Tijou
authors.forename: Pierre
authors.initials: P
authors.lastname: Pacaud
authors.forename: Gervaise
authors.initials: G
authors.lastname: Loirand
mesh_terms: D015906:Angioplasty, Balloon, Coronary / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D023903:Coronary Restenosis / Q000209:etiology; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D003331:Coronary Vessels / Q000254:growth & development / Q000473:pathology* / Q000601:surgery; D054855:Drug-Eluting Stents / Q000009:adverse effects*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009389:Neovascularization, Pathologic; D011108:Polymers; D014057:Tomography, X-Ray Computed
chemical_list: D011108:Polymers