Abstract 11160: Impact of In-Stent Neoatherosclerosis on Bare-Metal Stent Thrombosis Beyond 3 Years
Purpose: The purpose of this study was to investigate the association between nouveau atherosclerotic changes after the bare-metal stent implantation and stent thrombosis (ST).
Methods: From September 2002 to February 2010, thrombus aspiration was performed in 102 patients with definite bare-metal ST according to the Academic Research Consortium definition. Of these cases, 40 were early ST (within 30 days); 20 were late ST (between 31 and 365 days); and 42 were very late ST (> 1 year). To evaluate progressive atherosclerotic lesions within the stents, fragments of vulnerable plaques such as thin fibrous cap, formy macrophage and cholesterol crystal in the aspirated thrombi were evaluated.
Results: Mean age was 68 ±10 years, and 89 (87.3%) of patients were male. One patient with early ST was excluded due to insufficient material for histopathological analysis. Time distribution plots of pathological findings (Figure) showed formy macrophages, choresterol cristals, or thin fibrous caps were observed within 7 days (9 out of 35 patients) or beyond 3 years (13 out of 33 patients) after the index stent deployment, except for 2 cases. Fragments of vulnerable plaque retrieved from patients with EST within 7 days after stenting would be components of the culprit lesion where initial stents were deployed. Formy macrophage was observed in 13 (31.0%) patients with very late ST compared with one (5.0%) patient with late ST (p = 0.025), and 9 (22.5%) patients with early ST, respectively. Cholesterol crystal was observed in 8 (19.0%) patients with very late ST, one (5.0%) patient with late ST, and 7 (17.5%) patients with early ST, respectively.
Conclusion: Chronic inflammatory responses to the metal prosthetic device resulted in activation of macrophages and lymphocytes which eventually formed a necrotic core covered by a thin fibrous cap. These nouveau atherosclerotic changes caused very late ST beyond 3 years after bare-metal stent implantation.
- © 2011 by American Heart Association, Inc.