|April 7, 2017
J. Med. Devices
, (2017); doi: 10.1115/1.4036391
Overlapping stents are widely used in vascular stent surgeries. However, the rate of stent fractures (SF) and in-stent restenosis (ISR) after using overlapping stents is higher than those after using a single stent. The current studies to investigate the nature of overlapping stents were mainly based on medical images, which can only reveal the effect of surgery without providing insights on how stent overlapping influences the implantation process. In this paper, a finite element analysis of overlapping stent implantation process was performed to study the interaction between overlapping stents. Four different cases based on three typical stent overlapping modes and two classical balloons were carried out. The results showed that overlapping contact patterns among struts were edge to edge, edge to surface and non-contact. These were mainly induced by the non-uniform deformation of stent in the radial direction and stent tubular structures. Meanwhile the results showed the most of contact pressure concentrated occurred in the edge of overlapping struts. In the stent overlapping evolution, the pattern of most contacts was edge to edge contact at beginning; and edge to surface contact pattern occurred as the contact pressure increase. The interactions between overlapping stents suggest that the failure of overlapping stent frequently occurs in the edge of stent, it matches favorably to an experiment about the safety of overlapping stent. This paper provides a fundamental understanding of overlapping stent’s mechanical properties.