Increased thin-cap neoatheroma and periprocedural myocardial infarction in drug-eluting stent restenosis: multimodality intravascular imaging of drug-eluting and bare-metal stents.

BACKGROUND Re-endothelialization is delayed after drug-eluting stent (DES) implantation. In this setting, neointima is more prone to become lipid laden and develop neoatherosclerosis (NA), potentially increasing plaque vulnerability. METHODS AND RESULTS Optical coherence tomography and near-infrared spectroscopy with intravascular ultrasound were used to characterize NA in 65 (51 DES and 14 bare-metal stents) consecutive symptomatic patients with in-stent restenosis. Median duration poststent implantation was 33 months. Optical coherence tomography-verified NA was observed in 40 stents with in-stent restenosis (62%), was more prevalent in DES than bare-metal stents (68% versus 36%; P=0.02), and demonstrated significantly higher prevalence of thin-cap neoatheroma (47% versus 7%; P=0.01) in DES. Near-infrared spectroscopy assessment demonstrated that the total lipid core burden index (34 [interquartile range, 12-92] versus 9 [interquartile range, 0-32]; P<0.001) and the density of lipid core burden index (lipid core burden index/4 mm, 144 [interquartile range, 60-285] versus 26 [interquartile range, 0-86]; P<0.001) were higher in DES compared with bare-metal stents. Topographically, NA was classified as I (thin-cap NA), II (thick-cap NA), and III (peri-strut NA). Type I thin-cap neoatheroma was more common in DES (20% versus 3%; P=0.01) and in areas of the stented segment without significant in-stent restenosis (71%). Periprocedural myocardial infarction occurred only in DES (11 versus 0; P=0.05), of which 6 (55%) could be attributed to segments with >70% in-stent restenosis. By logistic regression, prior DES was the only independent predictor of both NA (odds ratio, 7.0; 95% confidence interval, 1.7-27; P=0.006) and periprocedural myocardial infarction (odds ratio, 1.8; 95% confidence interval, 1.1-2.4; P=0.05). CONCLUSIONS In-stent thin-cap neoatheroma is more prevalent, is distributed more diffusely across the stented segment, and is associated with increased periprocedural myocardial infarction in DES compared with bare-metal stents. These findings support NA as a mechanism for late DES failure.