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Serial long-term evaluation of neointimal stent coverage and thrombus after sirolimus-eluting stent implantation by use of coronary angioscopy
  1. Masamichi Takano1,
  2. Masanori Yamamoto1,
  3. Yong Xie1,
  4. Daisuke Murakami1,
  5. Shigenobu Inami1,
  6. Kentaro Okamatsu1,
  7. Koji Seimiya1,
  8. Takayoshi Ohba1,
  9. Yoshihiko Seino1,
  10. Kyoichi Mizuno2
  1. 1
    Department of Internal Medicine, Chiba-Hokusoh Hospital, Nippon Medical School, Chiba, Japan
  2. 2
    Division of Cardiology, Nippon Medical School, Tokyo, Japan
  1. Dr M Takano, Department of Internal Medicine, Chiba-Hokusoh Hospital, Nippon Medical School, 1715 Kamakari, Imba, Chiba, 270-1694, Japan; takanom{at}


Objective: Progression of neointimal stent coverage (NSC) and changes in thrombus were evaluated serially by coronary angioscopy for up to 2 years after sirolimus-eluting stent (SES) implantation.

Methods: Serial angioscopic observations were performed in 20 segments of 20 patients at baseline, at 6 months and at 2 years after SES implantation. NSC was classified as follows: 0, uncovered struts; 1, visible struts through thin neointima; or 2, no visible struts. In each patient, maximum and minimum NSC was evaluated. Existence of thrombus was also examined.

Results: The maximum NSC increased from 6 months to 2 years (mean (SD) 1.2 (0.4) vs 1.8 (0.4), respectively, p = 0.005), while the minimum NSC did not change (0.7 (0.5) vs 0.8 (0.4), respectively, p = 0.25). The prevalence of patients with uncovered struts did not decrease from 6 months to 2 years (35% vs 20%, respectively, p = 0.29). Although there were no thrombus-related adverse events, new thrombus formation was found in 5% of 6-month, and in 20% of 2-year follow-up evaluations. The prevalence of thrombus inside the SES at baseline, 6 months and 2 years was similar (40%, 40% and 30%, respectively; p = NS).

Conclusions: Neointimal growth inside the SES progressed heterogeneously. Uncovered struts persisted in 20% of the patients for up to 2 years and subclinical thrombus formation was not uncommon.

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  • Conflict of interest: None.

  • Abbreviations:
    late stent thrombosis
    neointimal stent coverage
    sirolimus-eluting stent