title: Distribution of angiographic measures of restenosis after drug-eluting stent implantation.
abstract: BACKGROUND
  A bimodal distribution of measures of restenosis has been demonstrated at 6-8 months after bare metal stent implantation. Drug-eluting stent (DES) treatment has attenuated the impact of certain factors (eg, diabetes) on restenosis but its effect on the distribution of indices of restenosis is not known.
  
  
  OBJECTIVE
  To perform a detailed analysis of the metrics of restenosis indices after DES implantation. Design, settings,
  
  
  METHODS
  Prospective observational study of patients undergoing DES implantation (Cypher, sirolimus-eluting stent; or Taxus, paclitaxel-eluting stent) at two German centres, with repeat angiography scheduled at 6-8 months after coronary stenting.
  
  
  METHODS
  In-stent late luminal loss (LLL) and in-segment percentage diameter stenosis (%DS) as determined by quantitative coronary angiography at recatheterisation.
  
  
  RESULTS
  Paired cineangiograms were available for 2057 patients. Overall mean (SD) LLL was 0.31 (0.50) mm; mean (SD) %DS was 30.3 (15.7)%. Distribution of both LLL and %DS differed significantly from normal (Kolmogorov-Smirnov test; p<0.001 for each). For both parameters a mixed distribution model better described the data (likelihood ratio test with 3df; p<0.001 for each). This consisted of two normally distributed subpopulations with means (SD) of 0.10 (0.25) mm and 0.69 (0.60) mm for LLL, and means (SD) of 22.2 (8.6)% and 40.1 (16.6)% for %DS. The results were consistent across subgroups of DES type, "on-label" versus "off-label" indication, and presence or absence of diabetes.
  
  
  CONCLUSIONS
  LLL and %DS at follow-up angiography after DES implantation have a complex mixed distribution that may be accurately represented by a bimodal distribution model. The introduction of DES treatment has not resulted in elimination of a variable propensity to restenosis among subpopulations of patients with stented lesions.
authors.affiliation: Deutsches Herzzentrum München, Lazarettstrasse 36, 80636 Munich, Germany. byrne@dhm.mhn.de
authors.forename: R A
authors.initials: RA
authors.lastname: Byrne
authors.forename: S
authors.initials: S
authors.lastname: Eberle
authors.forename: A
authors.initials: A
authors.lastname: Kastrati
authors.forename: A
authors.initials: A
authors.lastname: Dibra
authors.forename: G
authors.initials: G
authors.lastname: Ndrepepa
authors.forename: R
authors.initials: R
authors.lastname: Iijima
authors.forename: J
authors.initials: J
authors.lastname: Mehilli
authors.forename: A
authors.initials: A
authors.lastname: Schömig
mesh_terms: D000368:Aged; D001807:Blood Vessel Prosthesis; D016009:Chi-Square Distribution; D017023:Coronary Angiography / Q000706:statistics & numerical data; D023903:Coronary Restenosis / Q000000981:diagnostic imaging* / Q000473:pathology; D054855:Drug-Eluting Stents / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D017202:Myocardial Ischemia / Q000628:therapy; D017239:Paclitaxel / Q000008:administration & dosage; D011446:Prospective Studies; D011475:Prosthesis Failure; D020123:Sirolimus / Q000008:administration & dosage; D016896:Treatment Outcome; D050257:Tubulin Modulators / Q000008:administration & dosage
chemical_list: D050257:Tubulin Modulators; D017239:Paclitaxel; D020123:Sirolimus