[Morphological findings after stent implantation in the carotid artery]

This report describes the pathological-anatomical and immunohistochemical findings of carotid arteries after incorporation of self-expanding metal stents. Ten stent specimens were examined. All specimens displayed variable expression patterns of chronic low-grade foreign body reactions in the vicinity of the incorporated stent struts as characterized by the appearance of CD68-positive macrophages and mainly CD3- and CD45-R0-positive T lymphocytes. Overwhelming proliferations in relation to intimal hyperplasia can be regarded as the main cause of stent-associated vascular restenosis. After a period of 6 months the expression of factor VIII-positive neoendothelial cells on the luminal surface can be detected in individual cases. Reactions of the vascular wall depend on the state of the underlying atherosclerotic lesions prior to stenting. In cases of predominantly atheromatous soft plaques, the typical reaction pattern triggered by the metallic foreign body pressed into vessel tissue can be absent. In summary, the morphological findings show a chronic tissue reaction in response to stent incorporation. In addition, individually differing reaction patterns ranging from discrete inflammatory changes to massive stenoses were identified and documented.