Comparison of in-stent neoatherosclerosis and tissue characteristics between early and late in-stent restenosis in second-generation drug-eluting stents: an optical coherence tomography study.

Optical frequency domain imaging (OFDI) was utilized to compare the prevalence of neoatherosclerosis (NA) and morphological characteristics of the neointimal tissue in second generation drug eluting stent (G2-DES)-treated lesions between early (<1 year, E-ISR) and late (>1 year, L-ISR) in-stent restenotic phases. Data comparing NA and in vivo tissue characteristics between early and late in-stent restenosis (ISR) after implantation of G2-DES is limited. An OFDI analysis was performed in 50 G2-DESs {35 everolimus-eluting stent [22 cobalt-chromium (CoCr), 13 platinum-chromium (PtCr)], and 15 biolimus-eluting stent [BES]} ISR lesions (46 consecutive patients) undergoing target lesion revascularization, classified as E-ISR (n = 22 lesion) and L-ISR (n = 28 lesion). NA, defined as a neointima formation containing lipids or calcification was observed in fewer than half (24/50) of all ISR lesions with no significant difference between E-ISR and L-ISR lesions (50 vs. 46.4%, p = 0.8). There were also no significant differences in the morphological appearance and tissue characteristics between E-ISR and L-ISR lesions. ISR was more likely to occur earlier [median 8.6 (8.3-8.9) months] after PtCr-EES implantations (12 lesions vs. 1, p < 0.001), while 3/4 of the BES ISR lesions and more than 2/3 of the CoCr-EES ISR lesions were observed after 1 year of implantation [median 21.3 (20.7-27.5) months, p < 0.001]. Acknowledging some limitations, our observations may suggest that the prevalence of neoatherosclerosis and the morphological appearance, and tissue characteristics of G2-DESs restenotic lesions are similar between the early and late restenotic phases. Certain platforms (PtCr-EESs) may have preferentially presented with early ISR.