In silico assessment of the effects of material on stent deployment

Investigation of Drug Eluting Stents performance in human atherosclerotic artery through in silico modeling

Atherosclerosis is a chronic inflammatory disease associated with heart attack and stroke. It causes the growth of atherosclerotic plaques inside the arterial vessels, which in turn results to the reduction of the blood flow to the different organs. Drug-Eluting Stents (DES) are mesh-like wires, carrying pharmaceutical coating, designed to dilate and support the arterial vessel, restore blood flow and through the controlled local drug delivery inhibit neo-intimal thickening. In silico modeling is an efficient method of accurately predicting and assessing the performance of the stenting procedure. The present in silico study investigates the performance of two different stents (Bare Metal Stent, Drug-Eluting Stent) in a patient-specific coronary artery and assesses the effect of stent coating, considering that the same procedural approach is followed by the interventional cardiologist. The results demonstrate that even if small differences are obtained in the two models, the incorporation of the stent coatings (in DES) does not significantly affect the outcomes of the stent deployment, the stresses and strains in the scaffold and the arterial tissue. Nevertheless, it is suggested that regarding the DES expansion, higher pressure should be applied at the inner surface of the stent.

A Three-Dimensional Finite Element Analysis of Aramany Class I Obturator Fabricated with Different Alloys

Aim

The aim of the research was to develop a model that accurately represents an Aramany class I defect and its obturator prostheses fabricated with cobalt-chromium alloy and titanium alloy to compare the deflection and the stress distribution in the rehabilitated area.

Materials and Methods

Aramany class I defect and the obturator prostheses were generated geometrically using ANSYS 14.5; both were superimposed on each other to mimic the prostheses and the maxilla as one unit. Meshing of models was carried out using hypermesh software and materialistic properties were assigned. The 120 newton load was constituted on the teeth in different directions.

Statistical Analysis Used

Statistical analysis of Finite element was not possible. Self-explanatory decoding results in the software were used.

Results

The stress distribution and deflection executed by ANSYS provided results that enabled the tracing of Von Mises stress and deflection field in the form of color-coded bands with values in mega pascal.

Conclusions

The study shows that Von Mises stresses are higher for the frame work fabricated with cobalt-chromium alloy compared to titanium alloy. The framework made of titanium alloy showed more deflection than cobalt-chromium alloy.