Computer-Aided Analysis of the Corrosion Inhibition by Carbon-Based Thin-Film Coating on Vascular Bare Metal Stent Models

A simulation study of inhibiting the corrosion and corrosion-based restenosis is presented by diamond-like carbon (DLC) thin-film coating on bare-metallic intravascular stent models. The stents are designed and placed in a blood vessel model including a fatty-plaque layer in the study. 316L-stainless steel, CoCr-alloy, and nitinol are assigned to the stent models considering stent manufacturing. Modeled stents are coated with a carbon-based structure that mimics the DLC thin film. The electrochemical simulations are performed under the dynamic non-Newtonian blood flow condition for a 1 year period. Electrolytic current densities, corrosion, and restenosis rates of the bare and coated stents are simulated using time-dependent laminar flow and corrosion modules in multiphysics analysis software. Among the bare-stent models, the highest corrosion rate is observed for 316L with 79 µm year−1 and the minimum corrosion rate is observed for nitinol with 9 µm year−1. Restenosis rates increase up to 36 µm year−1 due to the charged-particle adhesion on the bare stent surfaces. However, DLC-thin-film coating reduces corrosion and in-stent restenosis (ISR) rates down to 0.94 and 0.2 µm year−1 respectively. It can be concluded that surface passivation by thin-film DLC coating may be considered a promising candidate for novel stent designs having lower corrosion-based issues and ISR risks