New biocompatible polymer surface coating for stents results in a low neointimal response

Clinical studies indicate a more pronounced endothelial response after sten t implantation than after balloon inflation. This might be related to the m etal surface of the stent, and therefore it is speculated that coating of t he stent might partially prevent hyperplasia. One coated and one noncoated Palmaz-Schatz stent were implanted in two separate coronary arteries of sev en pigs. The coating was composed of methylmethacrylate (MMA) (hydrophobic, 70 mol %) and 2-hydroxyethyl methacrylate (HEMA) (hydrophilic 30 mol %). A fter sacrifice (3 weeks), cross sections were made of the stented areas. Ve ssel wall reaction was calculated both independently and dependently of loc al vessel wall injury due to the stent struts. Overall, vessel wall reactio n of the coated stents was lower than that of the non-coated stents. The de gree of hyperplasia was linearly related to the degree of stent-induced ves sel wall injury. Analyses of all the struts showed that significantly less hyperplasia occurred in the coated versus noncoated stents. In this porcine coronary artery model, the MMA/HEMA stent coating resulted in significantl y reduced vessel wall response. However, it remains to be determined whethe r this favorable outcome will also be present in humans. (C) 2000 John Wile y & Sons, Inc.