Estimation and Comparison of Natural Frequency of Coronary Metallic Stents using Modal Analysis

A recent report states that more than 2,000,000 stents are used worldwide per year. Coronary artery obstruction is caused by the presence of high level of cholesterol which leads to ischemia. To prevent the elastic contraction of the artery that occurs immediately after the removal of the obstruction, typically a cardiovascular stent is placed. Structural integrity of the stent is an essential parameter determining the life span of the stent. In order to prevent the stent failure, we modelled a cardio vascular stent and subjected it to modal analysis to estimate the natural frequency of the stent. For this study three commonly used stent materials namely stainless steel (316L), cobalt-chromium alloy (CoCrMo) and titanium alloy (Ti₆Al₄V) were chosen. The natural frequencies were significantly different (P<0.05) for the three metallic stents at each corresponding modes. The vibrating modes at each frequency showed pronounced changes in their shapes for every stent material. The outcome of this work will be used by the medical product designers for designing new stents with better structural integrity by analyzing the modelled stent using ANSYS software before stent insertion, substituting in vivo experiment that is difficult and unpractical.