Fatigue life analysis and experimental verification of coronary stent

Abstract

A computational and experimental method on biomechanics of stent is presented to analyze the stress distribution of different phases and evaluate the fatigue life according to Goodman criteria. As a result, the maximum stress and alternating stress were always located at the curvature area of rings, the fatigue bands in the experiment also verified the computation rationality. Matching between the numerical simulation and experimental results was satisfactory, which proved that the finite element analysis could provide theoretical evidence and help design and optimize the stent structure.

Fatigue of Metallic Stents: From Clinical Evidence to Computational Analysis

“…Numerical results from the literature show that high stresses/strains usually develop near the most curved region of a stent strut due to stress concentration effects and small sizes, 5,12,42,43,53,58,79,82 in accordance with experimental evidences. 48,53 Such zones are the most vulnerable to the risk of long-term fatigue failure and they present the highest fatigue indicator factors (see Figs.…”

“…Several works have proposed Goodman analyses for 316L stainless steel, 10,12 L605 cobalt chromium, 41,42,53 and Nitinol 24,43,57 stents. The three-dimensional application of this criterion is generally based on the use of the first principal strains/ stresses as index of risk.…”

“…31 Currently, 85% of coronary interventions involve stents, 31 adding up to more than 1 million stents per year. 53 The successful clinical use of stents has highlighted issues associated with long-term endurance of implants. 3 Fractured stents lose their ability to scaffold occluded arteries and may cause restenosis, 75 thrombosis, 15 or artery perforation.…”

“…As an example, accelerated pulsatile testing at 65 Hz takes about 72 days to complete 4 9 10 8 cycles. 53 Therefore, computer-based design modeling represents an assessment tool for the prediction of stent performance and lifetime. 25,47 Such a tool allows for the improvement of both clinical procedures and stent design and it is now also accepted by regulatory bodies.…”

Fracture of Cardiovascular Stents in Patients With Congenital Heart Disease

“…57,[64][65][66][67][68][69][70][71][72] Computational analyses, such as finite element modeling, can be valuable for evaluating the mechanical response of a device to fatigue during the design process and other stages of stent development and use. Computational simulation is an attractive tool for this purpose because it can account for complex loading conditions that cannot be replicated on the bench, thus facilitating assessment of mechanical performance in more realistic environments.…”