Simulation of electrode impedance and current densities near an atherosclerotic lesion

A four-point electrode measuring impedance in the vicinity of an atherosclerotic lesion was modeled using FEM software. The simulation modeled the electrodes as being attached to an angioplasty balloon in a coronary artery. Impedance was calculated when the "balloon" was uninflated (not in contact with the lesion) and inflated (in contact with the lesion). Additionally, different lesion types (Va and Vb, as defined by the American Heart Association) and the effects of the low-conductivity calcium layer were considered. Results showed that the real component of the impedance was much higher when the electrodes were in contact with lesion. When the electrodes were not in contact with the lesion, the real component was low. Also, when the electrodes were in direct physical contact with the lesion, the difference between various lesion morphologies could be seen by observing the differences in the imaginary and phase component of the impedance. As a consequence of these simulations, it appears plausible that four-point electrodes mounted to an angioplasty balloon may be useful in determining whether a balloon has made contact with a lesion, and in characterizing that lesion