Stent implantation into the tracheo-bronchial system in XXXX : histopathologic sequelae in bare metal vs. drug-eluting stents.

@entity1 @entity95 @entity6377 @entity3446
BACKGROUND: Stent implantation into the tracheo-bronchial system may be life-saving in selected pediatric @entity1 with otherwise intractable stenosis of the upper airways. Following implantation, significant tissue proliferation may occur, requiring re-interventions. We sought to evaluate the effect of immunosuppressive coating of the stents on the extent of tissue proliferation in an animal model. METHODS: Bare metal and @entity3446 -coated stents (Bx Sonic and Cypher Select, Johnson _ Johnson, Cordis) were implanted into non-stenotic lower airways of New Zealand white @entity95 (weight 3.1 to 4.8  kg). Three stents with @entity3446 coating and six bare metal stents could be analyzed by means of histology and immunohistochemistry 12  months after implantation. RESULTS: On a macroscopic evaluation, all stents were partially covered with a considerable amount of whitish tissue. Histologically, these proliferations contained fiber-rich connective tissue and some fibromuscular cells without significant differences between both stent types. The superficial tissue layer was formed by typical respiratory epithelium and polygonal cells. Abundant lymphocyte infiltrations and moderate granulocyte infiltrations were found in both groups correspondingly, whereas @entity6377 was more pronounced around @entity3446 -eluting stents. CONCLUSIONS: After stent implantation in the tracheo-bronchial system of @entity95 , we found tissue reactions comparable to those seen after stent implantation into the vascular system. There was no difference between coated and uncoated stents with regard to quality and quantity of tissue proliferation. We found, however, a significantly different inflammatory reaction with a more pronounced @entity6377 in @entity3446 -coated stents. In our small series, drug-eluting stents did not exhibit any benefit over bare metal stents in an experimental setting.
