Comparison of the Cobalt Alloy and Stainless Steel Core(r) Stent in a Porcine Coronary Restenosis Model

ABSTRACT

BACKGROUND AND OBJECTIVES: The stent material and thickness may influence the rate of restenosis following coronary artery stenting. A thin strut cobalt-alloy stent has been developed in an attempt to reduce the restenosis rate, while maintaining the radiopacity and radial strength. The purpose of this study was to compare a stainless steel Core(r) stent (thickness 90 micrometer/HUMED Co. Ltd, Korea) with that of a cobalt alloy Core(r) stent (thickness 60 micrometer/HUMED Co. Ltd, Korea) in a porcine coronary stent restenosis model. MATERIALS AND METHODS: The cobalt alloy (Co-alloy) and stainless steel (SS) stents were implanted in 24 porcine coronary arteries. Four weeks after stenting, the pigs were sacrificed after quantitative coronary angiography (QCA). The coronary arteries were perfusion-fixed and stained, and a pathological examination performed by computer-aided histomorphometry. RESULTS: The minimal luminal diameter at 4 weeks was larger in the Co-alloy than the SS group according to the QCA (1.8+/-0.8 mm vs. 2.7+/-0.8 mm, p=0.019). The neointimal area was significantly smaller in the Co-alloy than the SS group (1.96+/-0.68 mm2 vs. 0.89+/-0.27 mm2, p<0.001). The intima/media area ratio was significant lower in the Co-alloy than the SS group (1.33+/-0.46 vs. 0.69+/-0.21, p=0.003). CONCLUSION: The thin strut cobalt alloy Core(r) stent significantly reduces the neointimal formation compared to the stainless steel Core(r) stent in a porcine coronary stent injury model.