A comparison between fractured Xience-like and Palmaz-like stents using a novel computational model.
We developed a novel mathematical model to study the mechanical properties of endovascular stents in their expanded state. The model is based on the one-dimensional theory of slender curved rods. Stent struts are modeled as linearly elastic curved rods that satisfy the kinematic and dynamic contact conditions at the vertices where the struts meet. A Finite Element Method for a numerical computation of its solution was developed and used to study mechanical properties of two commonly used coronary stents (Palmaz-like and Xience-like stent) in their expanded, fractured state. A simple fracture (separation), corresponding to one stent strut being disconnected from one vertex in a stent, was considered. Our results show a drastic difference in the response of the two stents to the physiologically reasonable uniform compression and bending forces. In particular, deformation of a fractured Xience-like stent (with one strut separated from one vertex) is significantly larger than that of a fractured Palmaz-like stent when exposed to uniform compression and bending. This presents conditions which may be a precursor for the clinically observed complications associated with in-stent thrombosis and in-stent restenosis of fractured coronary stents.
Tambaca
Josip
J
Department of Mathematics, University of Zagreb, Bijenicka 30, Croatia.
Canić
Suncica
S
Paniagua
David
D
D001696:Biomechanical Phenomena; D001698:Biomedical Engineering; D004548:Elasticity; D019544:Equipment Failure Analysis / Q000379:methods* / Q000706:statistics & numerical data; D020342:Finite Element Analysis; D006801:Humans; D066298:In Vitro Techniques; D008962:Models, Theoretical; D011474:Prosthesis Design; D011475:Prosthesis Failure; D015607:Stents