Introduction:
Frequency domain optical coherence tomography (FDOCT) can evaluate erythrocyte-rich thrombus, containing more inflammatory cells and reflect high thrombus burden, leading to impaired myocardial reperfusion in myocardial infarction patients.
Hypothesis:
The purpose of this study was to validate the quantified FDOCT signal analysis in evaluating the erythrocyte-rich thrombus with ex-vivo materials.
Methods:
We evaluated 55 specimens of coronary artery thrombus obtained by thrombectomy from 9 patients with acute coronary syndrome. The thrombi were immersed in saline immediately after the thrombectomy and FDOCT image acquisition was performed. Quantitative FDOCT analysis for all contiguous frames was performed by the dedicated automated software (OCT system software, Light Lab Inc.). In each sample, signal intensity and normalized standard deviation of signal (NSD) were evaluated quantitatively for a frame showing the biggest thrombus area. All thrombi were stained with hematoxylin-eosin, and the cellular component of erythrocyte were stained using monoclonal antibodies against a protein specific to erythrocyte membranes (glycophorin-A). Computer-assisted analysis was performed using dedicated software (WinROOF, Mitani Corp., Tokyo, Japan) for color identification of the erythrocyte area.
Results:
Erythrocyte-rich thrombus (n=26), defined as %erythrocyte area (erythrocyte area/total area X100)≧67%, showed higher [NSD / mean signal intensity X100] than white thrombus (n=21), defined as %erythrocyte area<33% (4.14±0.67 vs. 3.62±0.73, p=0.016). The optimal cut-off point of [NSD/mean signal intensity X100] for prediction of erythrocyte-rich thrombus was 4.20 (sensitivity: 50.0%, specificity: 81.9%, area under the receiver operating characteristic curve: 0.67, respectively).
Conclusions:
This study showed the utility of quantified FDOCT signal analysis on the evaluation of erythrocyte-rich thrombus.
Optical coherence tomography attenuation imaging for lipid core detection: an ex-vivo validation study