Vascular response to paclitaxel-eluting nitinol self-expanding stent in superficial femoral artery lesions: post-implantation angioscopic findings from the SHIMEJI trial (Suppression of vascular wall Healing after IMplantation of drug Eluting peripheral stent in Japanese patients with the Infra inguinal lesion: serial angioscopic observation)

The aim of this study was to elucidate the vascular responses to paclitaxel-eluting stent (Zilver PTX stent) in superficial femoral artery lesion at different elapsed times using angioscopy. Patients who received Zilver PTX stent implantation from five centers were enrolled. We performed angioscopic examinations at 2, 6, and 12 months after implantation and evaluated neointimal coverage (NIC) grade, intra-stent thrombus (IS-Th) grade, and presence of yellow plaque. NIC grade 0 was defined as stent struts exposed; grade 1, struts transparently visible although covered; grade 2, struts embedded in the neointima, but translucent; and grade 3, struts fully embedded and invisible. IS-Th was graded as follows: grade 0 (none), 1 (focal), and 2 (diffusely spread). Angioscopic follow-up evaluation was performed at 2 months (25 patients, 42 lesions), 6 months (18 patients, 23 stents), and 12 months (14 patients, 24 stents) after stent implantation. Dominant NIC grade significantly increased over time; however, 16.3% of the cases had NIC grade 1 or 2 at 12 months. IS-Th grade decreased; however IS-Th and yellow plaque were persistently observed in 62.5% and 83.3% cases, respectively, at 12 months. An ongoing healing response was observed at 12 months after implantation; however, thrombogenic findings were noted. Prolonged dual antiplatelet therapy could potentially enhance the clinical utility of Zilver PTX.