Objectives: The purpose of this study was to assess neoatherosclerosis in a registry of prospectively enrolled patients presenting with stent thrombosis using optical coherence tomography.
Background: In-stent neoatherosclerosis was recently identified as a novel disease manifestation of atherosclerosis after coronary stent implantation.
Methods: Angiography and intravascular optical coherence tomography were used to investigate etiologic factors of neoatherosclerosis in patients presenting with stent thrombosis >1 year after implantation (very late stent thrombosis [VLST]). Clinical data were collected according to a standardized protocol. Optical coherence tomographic acquisitions were analyzed in a core laboratory. Cox regression analysis was performed to identify factors associated with the formation of neoatherosclerosis and plaque rupture as a function of time.
Results: Optical coherence tomography was performed in 134 patients presenting with VLST. A total of 58 lesions in 58 patients with neoatherosclerosis were compared with 76 lesions in 76 patients without neoatherosclerosis. Baseline characteristics were similar between groups. In-stent plaque rupture was the most frequent cause (31%) in all patients presenting with VLST. In patients with neoatherosclerosis, in-stent plaque rupture was identified as the cause of VLST in 40 cases (69%), whereas uncovered stent struts (n = 22 [29%]) was the most frequent cause in patients without neoatherosclerosis. Macrophage infiltration was significantly more frequent in optical coherence tomographic frames with plaque rupture compared with those without (50.2% vs. 22.2%; p < 0.0001), whereas calcification was more often observed in frames without plaque rupture (17.2% vs. 4%; p < 0.0001). Implantation of a drug-eluting stent was significantly associated with the formation of neoatherosclerosis (p = 0.02), whereas previous myocardial infarction on index percutaneous coronary intervention was identified as a significant risk factor for plaque rupture in patients with neoatherosclerosis (p = 0.003). No significant difference was observed in thrombus composition between patients with or without neoatherosclerosis.
Conclusions: Neoatherosclerosis was frequently observed in patients with VLST. Implantation of a drug-eluting stent was significantly associated with neoatherosclerosis formation. In-stent plaque rupture was the prevailing pathological mechanism and often occurred in patients with neoatherosclerosis and previous myocardial infarction at index percutaneous coronary intervention. Increased macrophage infiltration heralded plaque vulnerability in our study and might serve as an important indicator.
Keywords: imaging; neoatherosclerosis; stent thrombosis.
Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.