Abstract 1928: Differences In Vascular Response Following Sirolimus And Paclitaxel Eluting Stents
Background Clinical randomized trials have reported different late loss between sirolimus-(Cypher) and paclitaxel- (Taxus) eluting stents however, the mechanism for this difference have not been fully explored. The aim of the current study was to determine the mechanisms responsible for these differences by histologic examination at autopsy.
Methods From a registry totaling 81 autopsy cases with DES, 42 patients (62 lesions; Cypher=33 and Taxus=29) who died >30 days following implantation were analyzed (We are still enrolling new cases). Morphometric analysis using calibrated software was performed. Pathologic findings such as fibrin deposition, endothelialization, presence of giant cell, and eosinophil were also recorded.
Results Duration of implantation, number of stents per lesion, and stent length were similar between 2 groups. Extent of fibrin deposition was greater in Taxus vs. Cypher while the eosinophilic infiltration and giant cell reaction was significantly greater in Cypher vs. Taxus (Table⇓).
Conclusion Although both stents demonstrate delayed arterial healing, the vascular response due to the use of different drugs and polymer shows differences being greater fibrin deposition in Taxus than in Cypher while frequent hypersensitivity reactions, eosinophilic infiltrate and giant cell reaction was observed in Cypher than in Taxus. We therefore speculate that these differences may reflect a decrease in hypersensitivity reaction to the Taxus stent.