Electric impedance spectroscopy of human atherosclerotic lesions

Abstract Objective The aim of this in vitro study was to investigate the feasibility of a new highly flexible microelectrode on human tissue and its potential of differentiating atherosclerotic lesions by electric impedance spectroscopy (EIS). Methods Electric impedance measurements (EIM) were performed on 148 spots of 7 aortic and 6 femoral human arteries at 1kHz, 10kHz and 100kHz. Results According to the AHA classification 33 (25%) grade I lesions (PI), 34 (26%) grade II (PII), 21 (16%) grade III (PIII), 21 (16%) grade IV (PIV), 13 (10%) grade Va (PVa) and 10 (8%) grade Vb (PVb) could be identified by histology. At 1kHz, 10kHz and 100kHz the mean electric impedance (MEI) of PI, PII, PIII and PIV was statistically not different. At 100kHz the MEI of PVa showed significantly higher values compared to the MEI of PI (455±66Ω vs. 375±47Ω, p =0.05), PII (455±66Ω vs. 358±63Ω, p =0.007), PIII (455±66Ω vs. 342±52Ω, p =0.003), PIV (455±66Ω vs. 356±41Ω p =0.013) and the MEI of PVb was significantly increased compared to the MEI of PI (698±239Ω vs. 375±47Ω, p p p p p Conclusions EIM could be performed on human aortic and femoral tissue. The results show that EIS has the potential to distinguish between different plaque types.