Assessment of Coronary Stent Deployment in Tapered Arteries: Impact of Arterial Tapering

Abstract

Coronary stents are used to prop open blocked arteries in order to restore normal blood flow. A major setback in this technology is in-stent restenosis (ISR), which gravely limits the clinical success of stents, especially in tapered vessels. The present study used the finite element method to study the effects of arterial tapering on the biomechanical behavior of both stents and vessels during stent deployment inside tapered arteries. The effect of arterial tapering was demonstrated by a combination of corresponding tapered arteries with various tapering angles, including a straight artery case for comparison. Results indicated that an increase of vessel tapering led to an increase in stent radial recoil, stent tapering following expansion, and von Mises stresses on vessels. However, an increase of vessel tapering also led to a decrease in stent foreshortening. The analysis provides suggestions for clinical application in tapered vessels. The finite element method evaluated mechanical stent behavior in tapered vessels, and can help designers to optimize the design of stents for tapered vessels.

Finite element simulation and optimization of mechanical performance of the magnesium‐alloy biliary stent

“…The bile duct with larger β is, prone to cause ISR, and the short axis plane is more likely to be injured than the long axis plane. The value of the maximum von Mises stress in this research is about 0.220 MPa, while that in the vessel wall expanded by a stainless stent is 1 MPa, 6 and that in the vessel wall expanded by a poly-L-lactic acid (PLLA) stent is 3 MPa. 22 Accordingly, the magnesium alloy stent generated smaller concentration stress values in the bile duct wall than other stents, having a low risk level with reference to ISR, fully in agreement with the finding of Lu et al 27 The incomplete stent apposition caused by the gap between the outer surface of the stent and the inner wall of the bile duct may result in stent shifting.…”

“…In the process of stent expansion, the stent deformation, as well as the shortening speed and recoil force of the stent, and so on, caused by the extrusion and the shape of lumens 5–7 and diseased tissues, 8,9 has a great influence on the expansion performance of the stent. Of course, the mechanical behavior of the expansion of the stent in different lumens will, in turn, affect the biomechanical environment of the lumen wall in contact with the stent, and may change the geometry of the lumen, and the upper stress of the lumen wall caused by the expansion of the stent plays an important role in the occurrence of restenosis.…”

A Systematic Review on Cardiovascular Stent and Stenting Failure: Coherent Taxonomy, Performance Measures, Motivations, Open Challenges and Recommendations

“…Moreover, the effects of the artery tapering level on the structural properties of coronary stent design as well as its biomechanical influence on the blood-vessel during stent deployment were sought [75]. In 2014, McGrath et al [76] investigated the axial buckling which observed through crimping of a long diameter Nitinol stent and through clarification of the buckling mechanism to remove it from the design. However, for investigating whether stent and blood-vessel deformation have a main effect on the hemodynamic environment in stented coronary arteries [77].…”

“…and radiopacity have been enhanced [21], [29], [35], [51], [61], [66]. As well as, the biodegradable stent (BDS) give the possibility to improve long-term patency rates for supporting the artery wall to heal, other researchers examined the mechanical properties for fully covered biodegradable stent by using finite element method (FEM) [16], [27], [33], [43], [56], [76]. Nevertheless, the geometric of stents design response on the mechanical behavior which leads to innovate or develop the new generation of stent geometry, however, stent versus stent researches one kind of randomized trials to show superiority of the new stent designs that should be guarantee fatigue strength and a sufficient vessel scaffolding [3], [4], [15], [39], [50], [55], [71], [74].…”