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, patients: 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.
Main outcome measures: 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.
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Additional tables are published online only at http://heart.bmj.com/content/vol95/issue19
Funding RAB was supported by a Research Fellowship in Atherothrombosis from the European Society of Cardiology.
Competing interests AK has received lecture fees from Bristol-Myers, Cordis, Lilly, Medtronic and Sanofi-Aventis. No other authors have any conflict of interest to declare.
Ethics approval Approval from Deutsches Herzzentrum, Technische Universität, Munich, Germany and 1. Medizinische Klinik, Klinikum rechts der Isar, Technische Universität, Munich, Germany.
Provenance and peer review Not commissioned; externally peer reviewed.
See Editorial, p 1556