Electric impedance spectroscopy of human atherosclerotic lesions.
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+/-66Omega vs. 375+/-47Omega, p=0.05), PII (455+/-66Omega vs. 358+/-63Omega, p=0.007), PIII (455+/-66Omega vs. 342+/-52Omega, p=0.003), PIV (455+/-66Omega vs. 356+/-41Omegap=0.013) and the MEI of PVb was significantly increased compared to the MEI of PI (698+/-239Omega vs. 375+/-47Omega, p<0.001), PII (698+/-239Omega vs. 358+/-63Omegap<0.001), PIII (698+/-239Omega vs. 342+/-52Omegap<0.001), PIV (698+/-239Omega vs. 356+/-41Omegap<0.001), PVa (698+/-239Omega vs. 455+/-66Omega, p<0.001). Performing ROC analyses for the detection of grouped PVa/PVb lesions, the largest AUC was found at 100kHz with a cut-off value of 441Omega presenting a sensitivity of 74% and a specificity of 94%.


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.
First Department of Medicine, University Hospital of Mannheim, Faculty of Medicine Mannheim, University of Heidelberg, Heidelberg, Germany. ines.streitner@med.ma.uni-heidelberg.de
Ines
I
Streitner
Markus
M
Goldhofer
Sungbo
S
Cho
Hagen
H
Thielecke
Ralf
R
Kinscherf
Florian
F
Streitner
Jürgen
J
Metz
Karl K
KK
Haase
Martin
M
Borggrefe
Tim
T
Suselbeck
D001011:Aorta / Q000503:physiopathology; D050197:Atherosclerosis / Q000175:diagnosis / Q000473:pathology* / Q000503:physiopathology; D017097:Electric Impedance; D005263:Femoral Artery / Q000503:physiopathology; D006801:Humans; D008839:Microelectrodes; D011379:Prognosis; D013057:Spectrum Analysis / Q000379:methods; D017539:Tunica Intima / Q000473:pathology; D017540:Tunica Media / Q000473:pathology