Biomechanical behaviour of coronary stent design with OCC technology

Purpose: The work presents results of stresses and strains of three-layer vascular stent (Cr-Ni-Mo - Ta - Cr-Ni-Mo) and one-layer uniform one (Cr-Ni-Mo) used in operative cardiology. Design/methodology/approach: On the basis of the geometrical model a finite element mesh was generated. The discretization process was realized with the use of the SOLID95 element. The set boundary conditions represented the phenomena which occur during baloon expanding. Findings: The numerical analysis of the three-layer stent showed diverse distribution of stresses and strains in the individual layers. Minimum stresses in the analyzed range of expansion diameters (d=2.25-3.50 mm) were observed in the middle layer made of tantalum. Maximum stresses were observed in the layer made of the stainless steel. Research limitations/implications: Values of stresses and strains in different stents' regions caused by applied displacements are valuable information for appropriate design of the geometry, hardening of the metallic biomaterial and forming of physio-chemical properties of surface layer. Originality/value: The obtained results are valuable for selection of surface layer which is mainly responsible for ensuring proper hemocompatibility of the stent. The deformable surface layer is an effective way to reduce the surface reactivity of the stent in blood environment and in consequence coagulation.