Vol.:(0123456789) 1 3 The International Journal of Cardiovascular Imaging https://doi.org/10.1007/s10554-020-01877-7 ORIGINAL PAPER Very late‑phase vascular response after everolimus‑eluting stent implantation assessed by optical coherence tomography Amir Kh. M. Khalifa 1  · Yasushi Ino 1  · Takashi Kubo 1  · Takashi Tanimoto 1  · Kunihiro Shimamura 1  · Yasutsugu Shiono 1  · Masahiro Takahata 1  · Kosei Terada 1  · Daisuke Higashioka 1  · Teruaki Wada 1  · Akira Taruya 1  · Hiroki Emori 1  · Yosuke Katayama 1  · Manabu Kashiwagi 1  · Akio Kuroi 1  · Yoshiki Matsuo 1  · Suwako Fujita 1  · Atsushi Tanaka 1  · Takeshi Hozumi 1  · Takashi Akasaka 1 Received: 18 January 2020 / Accepted: 2 May 2020 © Springer Nature B.V. 2020 Abstract Long-term safety of second generation drug-eluting stents (DES) has not yet been evaluated. We sought to evaluate the very late phase (> 3 years) vascular response after second generation everolimus-eluting stent (EES) as compared with frst genera- tion sirolimus-eluting stent (SES) by using optical coherence tomography (OCT). We examined the vascular response in 39 patients with a total of 55 DESs [31 EESs (mean 54 months after stenting) and 24 frst generation SES (mean 66 months after stenting)] by OCT. The frequency of lesions with any malapposed stent struts (19% vs. 46%, p = 0.035) and evagination (6% vs. 42%, p = 0.002) was signifcantly lower. Segments with malapposed stent struts were signifcantly shorter (0.4 ± 0.9 mm vs. 1.9 ± 3.5 mm, p = 0.024), maximal malapposition area and malapposition volume were signifcantly smaller (0.26 ± 0.38 mm 2 vs. 0.95 ± 1.54 mm 2 , p = 0.019, and 0.78 ± 1.35 mm 3 vs. 6.22 ± 15.76 mm 3 , p = 0.016, respectively) in EES. Compared with frst generation SES, second generation EES showed more favourable vascular responses at the very late phase. Keywords Late vascular response · Optical coherence tomography · Everolimus-eluting stent · First generation drug- eluting stent · Stent malapposition Introduction Drug-eluting stents (DES) have markedly reduced the mid- term (< 12 months) incidence of angiographic restenosis and target lesion revascularization (TLR) after stent implantation in comparison with bare-metal stents (BMS) [1, 2]. How- ever, late-phase clinical events, including late stent thrombo- sis and delayed restenosis, termed as late DES failure, have been proposed as potential concerns after frst generation DES implantation [3, 4]. Several pathological and optical coherence tomography (OCT) studies have demonstrated that delayed arterial healing with poor strut coverage and/or strut malapposition have been identifed as major substrate responsible for late and very late stent thrombosis (LST/ VLST) after frst generation sirolimus-eluting stent (SES) [5–8]. Furthermore, previous studies have demonstrated that atherogenic changes within the neointima after stent implantation, termed as neoatherosclerosis (NA), is one of the major causes of late DES failure [9–12]. Several studies also suggested that chronic infammation, which induced by polymers of DES, develops delayed arterial healing and NA within frst generation DES-treated lesion and contributes toward late DES failure [6–10]. Compared with the frst-generation DES, the second-gen- eration DES, such as the everolimus-eluting stent (EES), have been developed to improve the safety profle by means of more biocompatible polymers, reduced drug dose with adapted release kinetics, and reduced strut thickness [13, 14]. These enhanced properties may diminish development of delayed arterial healing and NA. Some clinical trials demonstrated the superior efcacy and safety of EES within 3 years after stent implantation compared with frst genera- tion DES [13, 15]. However, long-term safety of EES has not yet been evaluated. We therefore evaluated the very late phase (> 3 years) vascular response after second-generation EES as compared with frst generation SES by using OCT. * Yasushi Ino yasushi470923@yahoo.co.jp 1 Department of Cardiovascular Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan