Granulation tissue with eosinophil infiltration in the restenotic lesion after coronary stent implantation.

Although stents reduce the rate of vessel restenosis, in-stent restenosis is a recognized clinical problem and it appears that patients positive for allergic patch-test reactions to the stent components nickel and molybdenum have increased rates of it. A patient with angina pectoris had repeated episodes of restenosis after stent implantation and histological examination demonstrated granulation tissue with eosinophil infiltration in the restenotic lesion of the coronary artery. The patient was positive for an allergic reaction to the stent components.