Comparison of vascular response to the everolimus-eluting stent versus the paclitaxel-eluting stent: intravascular ultrasound results from the SPIRIT III trial

Aims: The purpose of this study was to investigate the vascular response of the everolimus-eluting stent (EES) compared with the paclitaxel-eluting stent (PES) using serial intravascular ultrasound (IVUS). Methods and results: Data were obtained from the SPIRIT III trial, a multicentre, 2:1 randomised, controlled study comparing EES and PES in de novo native coronary artery lesions. IVUS images were eligible for volumetric analysis at eight-month follow-up in 158 lesions (EES: 113, PES: 45). At eight months, EES had a smaller neointimal volume index (VI: mm(3)/mm) (EES: 0.4 +/- 0.4 vs. PES: 0.8 0.8 mm(3)/mm, p=0.002) and also a smaller % neointimal obstruction (EES: 7.1 +/- 6.7% vs. PES: 11.1 +/- 10.5%, p=0.005) compared with PES. While there was no significant change in vessel VI with EES, there was a significant increase in vessel VI in PES during eight-month follow-up (EES: 0.1 +/- 1.2 vs. PES: 1.2 0.8 mm(3)/mm, p=0.001). There were no statistical differences in the frequency of edge dissection or incomplete stent apposition between the two groups. Conclusions: Detailed IVUS analysis confirmed significantly less neointimal hyperplasia with EES compared with PES. While there was no increase in vessel volume with EES during the eight-month follow-up period, vessel enlargement was seen at the stented segment in PES.