The effect of CD34-capturing coronary stents with abluminal sirolimus coating on endothelial coverage

Abstract

Aims: Drug-eluting stents (DES) reduce neointimal hyperplasia by inhibition of vascular smooth muscle cell proliferation, concomitantly inhibiting stent endothelialisation and increasing the risk for stent thrombosis. The present study compares a contemporary DES to an endothelial progenitor cell-capturing DES (COMBO stent), with regard to intimal hyperplasia and endothelial coverage. Methods and results: Twelve New Zealand white rabbits were subjected to bilateral iliac artery stent placement. Each animal received both an everolimus-eluting stent (EES) and a COMBO stent. Four weeks after implantation, optical coherence tomography (OCT) was performed in six animals and tissue was harvested from the other six animals. Endothelial stent coverage assessed by scanning electron microscopy was significantly higher in COMBO stents than in EES (96.6±3.5% vs. 78.5±16.8%; p<0.05). Neointimal hyperplasia by OCT differed significantly (EES: 0.227±0.025 mm2 vs. COMBO: 0.188±0.044 mm2; p<0.05), but not by histology (EES: 0.823±0.200 mm2 vs. COMBO: 0.891±0.312 mm2; p=NS). No differences were observed in late loss between EES and COMBO stents (0.29±0.19 mm2 vs. 0.29±0.16 mm2; p=NS). Conclusions: Endothelialisation is significantly improved in the COMBO stent with equal inhibition of intimal hyperplasia, which may reduce thrombotic events after DES implantation and allow earlier discontinuation of dual antiplatelet therapy.