Abstract
Background: The geometry of stent in expansion process has great influence on restenosis of pathological vessels.
Objective: In this paper, the nonlinear finite element method is used to simulate the free expansion process of drug-eluting stents (DES). By analyzing the plastic strain nephograms at each stage in the process of stent deformation, the parameters of holes in the stent is determined. The major aim is to obtain the least tiny deformation occurred during the expansion process and then to guarantee the best drugloading property.
Method: Based on the results of stent expansion, an axially heterogeneous stent structure is set up. Changing rule of uniformity characteristics of the stent during the expansion process is concluded and then suggestions about how to adjust rigidity of the stent edge are also presented.
Result: It is shown that rigidity of the stent edge is a little lower than that of the inner part which is the major reason for dogboning phenomena. Based on this observation, an optimized type of DES with micro drug-loading holes is built up and analyzed in detail.
Keywords: Drug-eluting stent, finite element method, optimization design, dogboning phenomenon, heterogenous stent, restenosis rate.
Graphical Abstract