Finite Element Analysis of the Implantation Process of Overlapping Stents

Abstract

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 that of single stent implantations. Published studies investigating the nature of overlapping stents rely primarily on medical images, which can only reveal the effect of the surgery without providing insights into how stent overlap influences the implantation process. In this paper, a finite element analysis of the overlapping stent implantation process was performed to study the interaction between overlapping stents. Four different cases, based on three typical stent overlap modes and two classical balloons, were investigated. The results showed that overlapping contact patterns among struts were edge-to-edge, edge-to-surface, and noncontact. These were mainly induced by the nonuniform deformation of the stent in the radial direction and stent tubular structures. Meanwhile, the results also revealed that the contact pressure was concentrated in the edge of overlapping struts. During the stent overlap process, the contact pattern was primarily edge-to-edge contact at the beginning and edge-to-surface contact as the contact pressure increased. The interactions between overlapping stents suggest that the failure of overlapping stents frequently occurs along stent edges, which agrees with the previous experimental research regarding the safety of overlapping stents. This paper also provides a fundamental understanding of the mechanical properties of overlapping stents.

Fretting-corrosion of cardiovascular stent materials: The role of electrochemical polarisation on debris generation mechanisms

“…The advent of drug-eluting stents (DES) has gone some way to reducing the incidence of ISR but the issue remains in a non-negligible patient subset (5). In contrast with the clinical post-failure analysis conducted in orthopaedic implants, stents with ISR are typically not removed from the patient: re-stenting or bypass grafts are used (6,7).…”

“…Surface analysis of retrieved vascular devices has demonstrated that interfaces are susceptible to fretting-corrosion; the combined action of mechanical wear and corrosion at small displacement amplitudes. Evidence of fretting-corrosion has been observed at the braided stent strut interface (7,8) and in vivo at overlapping interfaces were the use of multiple stents may be necessary to treat long lesions and those arising from complex and dynamic biomechanics, particularly in peripheral stents (6,7,9). Such interfaces are shown in Figure 1.…”

Hemodynamics of Aortas with Multiple Overlapping Endografts: A New Design Consideration

“…Based on the result of the study conducted by Rikhtegar et al [68], in cases where stent overlap cannot be avoided, new deployment strategies or stent designs should be considered to reduce the size of low wall shear stress areas. Although customized vascular stent has not been a prevalent clinical practice, enhanced precision, reliability and affordability of such products could promote practice of employing personalized endografts [75,76].…”

Recent Advances in Manufacturing Innovative Stents

“…Overlapping stent design: Xu et al [242] studied the interaction types and location of overlapping stents. It was found that all the overlapping contact patterns between struts are edge-to-edge or edge-to-surface with no surface-to-surface contact pattern.…”