Thrombogenicity of sirolimus-eluting stents and bare metal stents: evaluation in the early phase after stent implantation.

BACKGROUND Thrombogenicitiy of drug-eluting stents is a matter of controversial debate. The aim of this study was to evaluate the thrombogenicity of sirolimus-eluting stents (SES) compared to bare metal stents (BMS) in a standardised in vitro model. MATERIALS AND METHODS Nine SES and nine BMS were implanted in tubing loops and nine loops without stent served as controls. Initially and after 90 minutes of blood circulation in a modified chandler loop model, thrombin-antithrombin III complex (TAT), PMN-elastase, factor XIIa, SC5b-9, sP-selectin and platelet count were measured. Expression of CD62P, CD45/41 and PAC-1 on platelets were determined by flow cytometry. RESULTS After 90 minutes, platelet count decreased significantly in the loops with BMS and SES (p<0.05). Levels of TAT, PMN-elastase and SC5b-9 were significantly elevated after 90 minutes in all loops (p<0.05). sP-selectin significantly increased in the loops with BMS and SES after 90 minutes. No significant changes occurred in any flow cytometric data. Platelet count, sP-selectin, TAT, PMN-elastase, SC5b-9, CD62P, CD41/CD45 and PAC-1 showed no significant difference between BMS and SES. CONCLUSION These data provide evidence that there is no difference in thrombogenicity of BMS and SES in the in vitro model.