Numerical Investigation on Flexibility of Metal Cardiovascular Stent

In practical field, “ease of stent delivery” during PCI is important for cardiologists since the stent goes through a very complex passage of blood artery before arriving the plaque blockage. However, there was no standard yet for representing it and thus various opinions existed for among cardiologists. In the current study, “ease of stent delivery” would be presented by flexibility. The flexibility of cardiovascular stent is determined numerically by curvature-index which is ratio of rotation angle to the length of the stent. The curvature-index was depicted at crimped or non-expanded and inflated or expanded conditions. Bending moment was applied to the stent in respect to x and y axes. Numerical work was performed by software ABAQUS. A stent model was open cell design made of stainless steel 316L with size of 100mm thick, strut and link width of 80mm, 20 mm long and initial outer diameter of 1.237 mm. Results on flexibility simulation showed that there were proportional values of bending moments of less than 0.4 N-mm and curvature index of less than 0.01 rad/mm. Beyond that value, the curvature index increased steeply. However, in general the expanded stent showed more flexible compared to that of non-expanded. To improve its flexibility with remained design, it could be carried out by reducing its thickness for less than 100 mm of its strut and link width for less than 80 mm.