Difference of vascular response between everolimus- and paclitaxel-eluting stents for small coronary artery disease: Optical coherence tomography analysis

Background: Previous clinical trials have demonstrated the clinical and angiographic superiority of everolimus-eluting stents (EES) compared with paclitaxel-eluting stents (PES) in the small coronary vessel. However, the differences of vascular response including assessment of morphological neointimal tissue (NIT) characteristics using optical coherence tomography (OCT) have not been fully evaluated. The aim of this study is to evaluate the differences of chronic vascular response following small coronary stenting between EES and PES using OCT.

Methods and results: A prospective OCT examination at 9 month follow-up was performed for 50 small coronary artery diseases (50 patients) treated by a single 2.5 mm stent for each stent group. Cross-sectional area within stent segments were analyzed at an interval of 1 mm. NIT structure (homogeneous or heterogeneous) was evaluated for qualitative assessment. Homogeneous NIT was observed significantly higher and heterogeneous NIT was lower in EES compared with PES (93% vs. 89%; p = 0.003, 6.5% vs. 10.3%; p = 0.002, respectively). The frequencies of exposed and malapposed struts were lower in EES compared with PES (0.2% vs. 1.7%; p = 0.0001, 0.1% vs. 0.3%; p = 0.001, respectively). NIT eccentricity index and NIT area were lower in EES compared with PES (0.69 ± 0.08 vs. 0.76 ± 0.10; p = 0.001, 0.97 ± 0.42 mm² vs. 1.27 ± 0.67 mm²; p = 0.01, respectively).

Conclusions: A favorable vascular response was observed after EES implantation compared with PES for small coronary artery disease. In addition, the characteristics of NIT after EES implantation were more stable than PES at 9 month follow-up.