2021 Volume 7 Issue 1 Pages 5-9
Background: Vascular response after intracoronary bare metal stent (BMS) implantation is biphasic, composed of early restenosis phase and chronic regression phase. The phase transition occurred at around 6 months after stenting. The biphasic vascular response after drug-eluting stent (DES) implantation has not yet been reported so far.
Aim: The aim of this study was to document if chronic neointimal regression occurs after implantation of Endeavor zotarolimus-eluting stent (E-ZES), the second-generation DES.
Methods: Enrolled were 12 E-ZES-implanted lesions without restenosis in 10 patients with coronary heart diseases. Coronary angioscopy was performed twice after stent implantation, at early phase (1–3 years) and chronic phase (3–6 years), to reveal neointimal coverage (NC) on stent struts. NC was semi-quantified from grade 0, no coverage; grade 1, thin coverage; grade 2, thick coverage; and grade 3, invisible stent struts fully embedded into thick neointima. Angioscopy also visualized presence of in-stent yellow plaques (YP) and mural thrombus (MT).
Results: Dominant NC grade at early phase was greater than that at chronic phase (2.91 ± 0.29 vs. 1.83 ± 0.83, P = 0.0008). YP was observed more frequently at early phase than at chronic phase (17% vs. 8%). MT was not detected at both phases.
Conclusions: Chronic neointimal regression occurred after E-ZES implantation although the vascular response to E-ZES progressed more slowly than BMS implantation.