Histopathological Comparison among Biolimus, Zotarolimus and Everolimus-Eluting Stents in Porcine Coronary Restenosis Model

Background and Objectives: The aim of this study was to examine the histolopathogical effects among the biolimus, zotarolimus, and everolimus eluting stent (EES) in the porcine coronary restenosis model. Subjects and Methods: Pigs were randomized into three groups in which the coronary arteries (15 pigs, 10 coronaries in each group) had either a biolimus A9 eluting stent (BES, n=10), zotarolimus eluting stent (ZES, n=10) or an EES (n=10). Histopathologic analysis was performed at 28 days after stenting. Results: There were no significant differences in the injury score among the three groups. There was a significant difference in the internal elastic lamina, lumen area, neointima area, percent area stenosis, and the fibrin and inflammation score among the three groups ($4.3{\pm}0.53mm^2$, $2.5{\pm}0.93mm^2$, $1.8{\pm}1.03mm^2$, $40.7{\pm}20.80%$, $1.7{\pm}0.41$, $1.4{\pm}0.72$ in the BES group vs. $5.1{\pm}0.55mm^2$, $2.3{\pm}1.14mm^2$, $2.8{\pm}1.00mm^2$, $55.4{\pm}21.23%$, $2.0{\pm}0.39$, $1.6{\pm}0.76$ in the ZES group vs. $4.4{\pm}0.53mm^2$, $1.7{\pm}1.22mm^2$, $2.8{\pm}1.23mm^2$, $64.0{\pm}26.00%$, $1.8{\pm}0.76$, $2.1{\pm}0.90$ in the EES group, respectively). BES is more effective in inhibiting neointimal hyperplasia compared to ZES and EES (p<0.0001). According to the fibrin and inflammation score, BES and EES are more effective in decreasing the fibrin deposition compared to ZES (p<0.001). Moreover, BES and ZES are more effective in reducing the inflammatory reaction compared to EES (p<0.001). Conclusion: The result demonstrates that BES shows better histopathological characteristics than ZES and EES at one month after stenting in the porcine coronary restenosis model.