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In-stent neoatherosclerosis: are first generation drug eluting stents different than bare metal stents? An optical coherence tomography study

Purpose: In-stent neoatherosclerosis has been recognised in pathologic specimens of bare metal stents (BMS), and recently in first generation drug eluting stents (1st-DES), as well. However, in vivo data are scarce. By optical coherence tomography, we investigated the incidence and morphological characteristics of neoatherosclerosis (NA) very late after BMS or 1st-DES implantation. Methods: From 1/1/2007 to 31/1/2012, 52 patients from two institutions underwent >24 months follow-up OCT assessment of a BMS or a 1st-DES (13 BMS – 39 1st-DES). NA was characterized using criteria for native atherosclerosis. Results: BMS had longer follow-up interval but no differences in clinical presentation at follow-up. No significant differences were evident in the incidence of NA, neointimal rupture, lipid content, neovascularization or macrophage infiltration between BMS and 1st-DES. There was however a trend for lower fibrous cap thickness (FCT) and for higher calcification in BMS (FCT: 51±31 μm vs. 92±59 μm, p=0.057; calcifications: 46.2% vs. 15.4%, p=0.051). 1st-DES with neoatherosclerosis had longer interval from implantation compared to 1st-DES with homogeneous coverage [Median 71 months (range 25-130) vs. 57 months (24-68), p<0.05], but there was no difference for BMS with or without neoatherosclerosis [Median 125 months (range 90-201) vs. 168 months (132-168), p=0.63]. Conclusions: The incidence and morphological characteristics of NA are similar between 1st-DES and BMS of more prolonged follow-up. Our findings suggest a time-dependent pattern in the incidence of NA in 1st-DES with 2-11 years follow-up.