The degradation degree was maximum, stating that that area was almost in a state of complete degradation. As it can be seen from the Figures 9 and 10, the biodegradation process occurred across the entire stent. However, the degradation rates were not uniform in different locations along the stent structure: The material at the reinforced strut had the quickest degradation speed whereas the material away from that area had a relatively slower degradation speed. Therefore, it can be observed that the degradation speed of the material is related to the initial strain value of the material prior to degradation, where the greater the initial strain level, the Catharanthine sulfate faster the degradation speed. After 30 days of degradation, the small area at the inner surface of the middle reinforced strut with larger initial strain, had a maximum degradation degree of 0.9, implying that that area was almost in a state of complete degradation. It was found that the stent degradation speed and location were closely related to the stress concentration on the stent after the implantation in the human body since the stents degraded at a relatively faster rate at the sites of stress concentration. When we further dilated the stents which were retrieved after the 6-month degradation, we found that all fracture sites were coincident with stress concentration 
regions with the faster rate of degradation. This study employed in vivo, in vitro and finite element analysis methods to investigate stent degradation and we found that the results of these methods were in good coherence with one another. The radial strength analysis of the bioabsorbable stent was used to verify the accuracy of the biodegradation property model. From a macroscopic point of view, the radial strength curve of the bioabsorbable stent decreased to some extent. Figure 11 shows the comparison of the radial strength in the FE analysis and the experiments. The trends of the radial strength from FEA simulations and experiment tests at different degradation time points were in good coherence. There are some factors Ginsenoside-F2 causing the deviations in the FE analysis In the experimental data of the material degradation, only data of pre-stretch value ranging from 0% to 40% was covered, the experimental data with larger magnitude of pre-stretch was however not taken into consideration; Material properties are closely related to the degradation degree but still, the experimental data did not include the data about the properties of the almost completely degraded material; During the analysis process, since the material had degraded completely, its material property was obtained from the extrapolation of the experimental data, which eventually caused deviation in the results. Furthermore, the experimental data did not include the data about the material properties after complete degradation and this caused certain influence on the accuracy of the FE analysis. Also, the theory of the fatigue analysis method for the bioabsorbable stent still requires further research. In future research work, the above mentioned assumptions and limitations will be taken into consideration. In this study, the FE analysis method of the biodegradation process of bioabsorbable stents was developed. The accuracy of this model was validated by the in vivo and in vitro experiments and the radial strength bench test. The results of the in vivo and in vitro studies and the finite element analysis are in good accordance. The trends in the stent degradation speed, degradation location and changes in the diameter were highly consistent in all the experiments. Therefore, the results of the in vitro experiment and finite element analysis could be used as tools for guidance and reference during stent design.