Abstract 14330: Effect of Strut Thickness on Atherosclerotic Change in Neointima Over An Extended Follow-up Period (≥ 5 Years) after Bare-metal Stent Implantation: In Vivo Optical Coherence Tomography Study
Background: Neointima of bare-metal stent (BMS) can transform into atherosclerotic plaque in the very late phase due to a persistent foreign-body inflammatory reaction to the metal. We sought to investigate whether the strut thickness may impact on atherosclerotic change in neointima ≥ 5 years after BMS implantation by using optical coherence tomography.
Methods: A total of 21 patients with BMS ≥ 5 years after implantation were enrolled. The strut was defined as thin when < 100μm and thick when ≥ 100μm. According to this criteria, patients were divided into 2 groups (thin-strut group; n=8, thick-strut group; n=13). Neointima was categorized into normal neointima, or lipid-laden intima with marked signal attenuation and a diffuse border region. The presence of intimal disruption, thrombus, and neovascularization was also evaluated.
Results: The mean stent length (18.3±5.4mm vs. 20.7±5.6mm, p=0.35), mean stent diameter (3.4±0.4mm vs. 3.3±0.5mm, p=0.64), and mean period after stenting (80±8 months vs. 88±18 months, p=0.25) were comparable between the 2 groups. Peri-strut neovascularization was a common finding in both groups (88% vs. 85%, p=1.0). The frequency of intra-intima neovascularization was similar between the 2 groups (50% vs. 69%, p=0.65). In the thick-strut group, lipid-laden intima (85% vs. 25%, p=0.0176), thin-cap fibroatheroma-like intima (54% vs. 0%, p=0.018), intimal disruption (46% vs. 0%, p=0.046), and thrombus (46% vs. 0%, p=0.046) were found more frequently. The incidence of symptomatic coronary events associated with the previously stented segment was higher in the thick-strut group than in the thin-strut group (77% vs. 0%, p=0.001).
Conclusions: A reduced strut thickness had favorable effects on atherosclerotic changes of neointima and coronary events in the very late phase after BMS implantation. Even in the drug-eluting stent era, the choice of a stent with a thinner strut thickness may lead to better long-term patient outcomes.
- © 2010 by American Heart Association, Inc.