Abstract 12933: Increased Lipid Tissue in the Neointima of Late Restenosis after Stent Implantation: Integrated Backscatter Intravascular Ultrasound Analysis for In-Stent Restenosis
Background: Although late restenosis is one of the long-term complications after stent implantation, the pathogenesis has not been fully elucidated. The purpose of this study is to compare the tissue characterization of neointima between early restenosis and late restenosis using integrated backscatter intravascular ultrasound (IB-IVUS).
Methods: A total of 73 consecutive patients with in-stent restenosis (ISR) after bare-metal stent (BMS, n=48) or sirolimus-eluting stent (SES, n=25) implantation were enrolled. All enrolled patients underwent initial follow-up angiography from 6 to 12 months after stent implantation. When ISR was detected at initial follow-up angiography, this lesion was classified as the early restenosis group. On the other hand, when ISR was detected at 13 months or later without ISR at initial follow-up angiography, this lesion was classified as the late restenosis group. Volumetric evaluation of neointima within the stented segment using IB-IVUS was performed.
Results: Late restenosis were observed in 21 lesions (15 lesions in SES, 6 lesions in BMS). A higher prevalence of late restenosis was observed in SES than in BMS (60.0% vs. 12.5%; p<0.001). As the clinical presentation at the onset of restenosis, acute coronary syndrome (ACS) was more often identified in patients with late restenosis than those of early restenosis (33.3% vs. 9.6%; p=0.016). On IB-IVUS analysis, the percentage of lipid tissue in the neointima was significantly higher in the late restenosis group than in the early restenosis group (29.9 ± 9.9% vs. 19.8 ± 11.3%; p<0.001). In subgroup analysis, similar results were observed after classification by stent type into BMS and SES (BMS; 29.7 ± 7.3% vs. 19.7 ± 11.5%; p=0.045, SES; 30.0 ± 11.1% vs. 20.7 ± 10.8%; p=0.048).
Conclusion: The onset of late restenosis tended to be more sudden than that of early restenosis. We could identified the significantly increased lipid tissue in the neointima of late restenosis compared to that of early restenosis, suggesting atherosclerotic change after stent implantation may be one of the possible mechanisms of late restenosis.
- © 2012 by American Heart Association, Inc.