Cre8™ coronary stent: preclinical in vivo assessment of a new generation polymer-free DES with Amphilimus™ formulation.

AIMS: This new generation of DES has attempted to improve clinical safety by avoiding the presence of polymers. The present preclinical in vivo study was designed to investigate the safety profile of Cre8™ stent. This is a new coronary stent based on Amphilimus™, a sirolimus formulated with a polymer-free amphiphilic carrier released from reservoirs machined onto the abluminal stent surface. METHODS AND RESULTS: Cre8™ stents were compared with two controls: R3 (the same platform only loaded with an amphiphilic carrier) and the Cypher Select Plus® stent (Cordis, Johnson & Johnson, Warren, NJ, USA). All devices (48 stents) were implanted in porcine coronary arteries with subsequent histological and morphometric evaluations at seven, 30 and 90 days. Early endothelisation at seven days was almost complete in all stents. Vessel wall histology at 30 days demonstrated a mild inflammation score in all groups (an inflammation score lower than 1 was observed in 100% of Cre8 stent, 71.5% for R3 and 66.7% for Cypher; p=n.s.) while morphometry showed a significantly smaller neointimal area in Cre8™ (Cre8 0.93±0.43 mm2; R3 1.49±0.67 mm2; Cypher 1.81±0.94 mm2; Cre8 vs. Cypher p<0.05); this difference was maintained after 90 days (inflammation score lower than 1 in 100% of Cre8 stent, 100% for R3 and 66.7% for Cypher; p=n.s. Neointimal area was 1.27±0.56 mm2 for Cre8, 1.74±0.60 mm2 for R3 and 2.79±1.14 mm2 for Cypher; Cre8 and R3 vs. Cypher p<0.05 while neointimal thickness was 0.15±0.07 mm for Cre8, 0.21±0.12 mm for R3 and 0.31±0.15 mm for Cypher; Cre8 vs. Cypher p<0.05). CONCLUSIONS: The most significant experimental evidence appears to be the absence of chronic inflammatory response in Cre8™ stent. This is expressed by a reduced neointimal thickness and inflammatory score at all follow-ups. Such an outcome positively compares with the other DES where a trend to neointimal growth and increased cell infiltration was observed.