ICCM Conferences, The 8th International Conference on Computational Methods (ICCM2017)

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Fatigue life prediction of stents in a realistic coronary stenosis model
xinyang cui

Last modified: 2017-05-26


Background The clinical outcome and fatigue life of stent are closely related to the biomechanical environment of coronary stenosis. In order to predict fatigue life of coronary stents, the stents’ adaptability and safety in a realistic stenosis model combined with the clinical data was studied in this paper.


Methods Coronary artery stenosis models were built with Mimics based on CT angiography (CTA) data. Finite element method (FEM) was used to simulate the stent expansion in a realistic and an idealized coronary stenosis model. The stress/strain of the two different models was compared. Based on the mechanical analysis, the influence of cyclic loading effect on the fatigue life of the stents was studied. Stents’ fatigue rupture was calculated with Goodman diagram, and the fatigue performance parameters such as the cycle to failure, the fatigue life, fatigue safety factor (FSF), cumulative fatigue damage rate were also analyzed.


Results The maximum stresses in the stent, plaque, and the vessel wall in the realistic stenosis model were 413.8 MPa, 6.06 MPa, and 3.39 MPa, respectively. While in the idealized model, they were 418.3 MPa, 4.46 MPa, and 1.13 MPa, respectively. Although the maximum stress was always located at the bending area of crowns, the stress distributions were different largely in the two models. The relative error ratios of the maximum stress in the plaque and vessel wall between the two models were 26.4%, 66.7%. In the fatigue analysis, the stent would not fail for fatigue rupture calculated by Goodman diagram. The closest point to the fatigue limit was also located at the inner bend of crowns. The predicted number of cycles to failure was 5.32*108, the fatigue life was 14 years, the FSF was 2.8, and the maximum cumulative fatigue damage rate was about 71.5%.


Conclusion The mechanical parameters (stress/strain) were associated with the realistic coronary stenosis model. It is feasible to use a realistic model to calculate the accurate stress/strain for a coronary stent to predict the dangerous point and to evaluate the accurate fatigue performance parameters. This method can serve as a useful tool to support interventional planning for stent implantation in order to minimize the risk of fatigue fracture.

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