Yonsei Med J.  2010 Nov;51(6):823-831. 10.3349/ymj.2010.51.6.823.

Comparisons of the Effects of Stent Eccentricity on the Neointimal Hyperplasia between Sirolimus-Eluting Stent versus Paclitaxel-Eluting Stent

• Kim BK
• Ko YG
• Oh S
• Kim JS
• Kang WC
• Jeon DW
• Yang JY
• Choi D
• Hong MK
• Ahn T
• Jang Y

• KMID: 1779626
• DOI: http://doi.org/10.3349/ymj.2010.51.6.823

Abstract

PURPOSE
Previous studies suggested that asymmetric stent expansion did not affect suppression of neointimal hyperplasia (NIH) after sirolimus-eluting stents (SES) implantation. The aim of this study was to evaluate the effects of stent eccentricity (SE) on NIH between SES versus paclitaxel-eluting stents (PES) using an intravascular ultrasound (IVUS) analysis from the randomized trial.
MATERIALS AND METHODS
Serial IVUS data were obtained from Post-stent Optimal Expansion (POET) trial, allocated randomly to SES or PES. Three different SE (minimum stent diameter divided by maximum stent diameter) were evaluated; SE at the lesion site with maximal %NIH area (SE-NIH), SE at the minimal stent CSA [SE-minimal stent area (SE-MSA)], and averaged SE through the entire stent (SE-mean). We classified each drug-eluting stents (DES) into the concentric (> or = mean SE) and eccentric groups (< mean SE) based on the mean value of SE.
RESULTS
Among 301 enrolled patients, 233 patients [SES (n = 108), PES (n = 125)] underwent a follow-up IVUS. There was no significant correlation between %NIH area and SE-NIH (r = - 0.083, p = 0.391) or SE-MSA (r = - 0.109, p = 0.259) of SES. However, SE-NIH of PES showed a weak but significant correlation with %NIH area (r = 0.269, p < 0.01). As to the associations between SE-mean and NIH volume index, SES revealed no significant correlation (r = - 0.001, p = 0.990), but PES showed a weak but significant correlation (r = 0.320, p < 0.01). However, there was no difference in the restenosis rate between the eccentric versus concentric groups of both DES.
CONCLUSION
This study suggests that lower SE of both SES and PES, which means asymmetric stent expansion, may not be associated with increased NIH.

Keyword

Drug-eluting stents; intravascular ultrasonography; restenosis

MeSH Terms

Aged
Angiography/methods
Coronary Restenosis/pathology/ultrasonography
*Drug-Eluting Stents
Female
Humans
Hyperplasia/*drug therapy/pathology
Immunosuppressive Agents/administration & dosage
Male
Middle Aged
Paclitaxel/*administration & dosage
Sirolimus/*administration & dosage
Tunica Intima
Ultrasonography, Interventional/methods

Figure

• 

  Fig. 1 Schematic examples of three different determinations of stent eccentricity (SE). SE is defined as minimum stent diameter (D1) divided by maximum stent diameter (D1'). Outer lager circle and smaller circle on each slice mean EEM and stent CSA, respectively. (A) SE-NIH was determined at the lesion site with maximal %NIH area on the follow-up IVUS. (B) SE-MSA was determined at the site with MSA. (C) SE-mean was determined by the averaged SE through the entire stent at the interval of 1 mm. EEM, external elastic membrane; CSA, cross-sectional area; NIH, neointimal hyperplasia; MSA, minimal stent area.

• 

  Fig. 2 Association between three different SEs and neointimal hyperplasia. (A) Correlation between SE-NIH (determined at the narrowest portion with large NIH on follow-up IVUS) and %NIH area. (B) Correlation between SE-MSA (determined at the site with minimal stent CSA) and %NIH area. (C) Correlation between mean SE (averaged value through the entire stent) and NIH volume index. SE, stent eccentricity; NIH, neointimal hyperplasia; IVUS, intravascular ultrasound; MSA, minimal stent area; CSA, cross-sectional area.

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