Evaluation of Neointimal Coverage at the Early Stage After Zotarolimus-Eluting Stents Implantation in Porcine Coronary Artery by Optical Coherence Tomography

Objective:To evaluate the neointimal coverage at the early stage after zotarolimus-eluting stents(ZES) implantation in porcine coronary artery by optical coherence tomography(OCT) and scanning electron microscope image. Methods:There were 18 mini-pigs used in our study,each one received a ZES implantation in its right coronary artery.Then the animals were examined at different time points as 3 groups of 7 days,14 days,and 28 days after the implantation,n=6 in each group.The neointimal coverage in stent surface was examined by OCT,the histological changes in related coronary segments were observed by scanning electron microscope. Results:OCT examination showed that there were significant differences of neointimal thickness in stent surface among 3 groups as at 7 days(61.3±37.7)μm,14 days(132.6±103.3)μm and 28 days(244.3±282.3)μm,P0.001 respectively.The rate of neointimal coverage also presented obvious differences among 3 groups,at 7 days(53.62 ± 2.49)%,and at 28 days it reached(94.88 ± 2.93)%.The scanning electron microscope image indicated that 7 days after implantation,the neointima were mainly having inflammatory cells,red blood cells and platelets,while 28 days after implantation,the smooth muscle cells,inflammatory cells and endothelial cells were more observed. Conclusion:Neointima could be clearly seen by OCT at 7 days after stent implantation and most of the struts were covered with neointima at 28 days after ZES implantation.