Characterization of Implanted Stents through Neointimal Tissue Bioimpedance Simulations

Abstract

This work describes how is possible the definition of the light hole or lumen in implanted stents affected by restenosis processes using the BioImpedance (BI) as biomarker. The main approach is based on the fact that neointimal tissues implied in restenosis can be detected and measured thanks to their respective conductivity and dielectric properties. For this goal, it is proposed a four-electrode setup for bioimpedance measurement. The influence of the several involved tissues in restenosis: fat, muscle, fiber, endothelium and blood, have been studied at several frequencies, validating the setup and illustrating the sensitivity of each one. Finally, a real example using a standard stent, has been analyzed for stable and vulnerable plaques in restenosis test cases, demonstrating that the proposed method is useful for the stent obstruction test. Bioimpedance simulation test has been performed using the electric physics module in COMSOL Multiphysics®.

Evaluation of Implanted Stent Occlusion Status Based on Neointimal Tissue Bioimpedance Simulations

“…As previously mentioned, FEA was performed with the COMSOL Multiphysics® computer program [19]. For each simulation, and therefore, for each frequency, a geometric (size) and electrical (conductivity and permittivity) description of the tissue layer under test was introduced.…”

“…Each one has its own electrical properties, derived from its electrical parameters, that is, conductivity (σ) and permittivity (ε) [23], which depend on frequency. The geometry of each layer as well as the assignment of the corresponding conductivity and permittivity at each operation frequency must be incorporated into the FEA [18,19,24]. Thus, the analysis is carried out for several types and sizes of tissues, reproducing the restenosis phenomenon for a given setup test.…”

“…There exist methods to monitor cell cultures in vivo based on their BI [17][18][19][20]. In [17], a cell-culture was transformed into a "biological oscillator" whose characteristic parameters (i.e., frequency, amplitude, phase, etc.)…”