Impact of different stent alloys on human vascular response to everolimus-eluting stent: an optical coherence tomography study: the OCTEVEREST.

BACKGROUND: New generation drug-eluting stents (DES) incorporate thinner struts and novel alloys to improve clinical performance. Nevertheless, the impact of novel stent materials and designs on human vascular response to DES remains elusive. We sought to evaluate the in-vivo coronary artery response to platinum-chromium (PtCr) versus cobalt-chromium (CoCr) stents featuring the same durable polymer and antiproliferative drug by optical coherence tomography (OCT). METHODS AND RESULTS: A total of 42 patients with de novo lesions in native coronary vessels was treated with PtCr-everolimus eluting stent (EES; n = 21) or CoCr-EES (n = 21). Angiography, intravascular ultrasound, and OCT were performed at the index procedure and 6-month follow-up. PtCr-EES and CoCr-EES had similar concentric expansion (stent eccentricity index; median 0.91 vs. 0.90, respectively, P = 0.47) and very low rate of strut malapposition (median 1.15 vs. 1.80%, P = 0.92) at post implantation. Proportion of struts embedded in tissue was lower in PtCr-EES compared to CoCr-EES (median 2.67 vs. 15.23%, P < 0.001). The primary prespecified end point, the percentage of uncovered struts per patient at 6 months follow-up, was 8.46% [interquartile range (IQR) = 3.05-17.26] in PtCr-EES and 5.88% (IQR = 1.35-13.27) in CoCr-EES (P = 0.36), whereas malapposed struts were observed in 0.00% (IQR = 0.00-0.25) versus 0.48% (IQR = 0.00-1.44), respectively, (P = 0.10). Strut-level neointimal thickness did not differ between the two platforms (median 0.09 vs. 0.08 mm, P = 0.49). CONCLUSIONS: Acute and mid-term responses to EES using PtCr or CoCr platforms were similar, with concentric stent expansion, low malapposition, similar strut coverage and limited amount of neointima. Conversely, at postprocedure, PtCr-EES had fewer embedded struts compared with CoCr-EES.