Abstract 3787: Impact of Intramural Thrombus on the Accuracy of Tissue Characterization by Virtual HistologyTM
Background: Virtual HistologyTM (VH) intravascular ultrasound (IVUS) enables to differentiate between 4 different tissue phenotypes: fibrous; fibro-fatty; necrotic core; and dense calcium. However, the current classification tree cannot differentiate the presence of intramural thrombus with other components. The aim of this study was to evaluate the impact of mural thrombus on the correlative accuracy between in vitro histopathology of coronary atheroscle-rotic plaque obtained by directional coronary atherectomy with corresponding in vivo tissue characterization obtained by VH-IVUS.
Methods: Coronary IVUS imaging of 30 coronary artery lesions in 28 patients were obtained using a 20-MHz phased-array IVUS catheter with the motorized pull-back system at 0.5 mm/s. Debulking region of in vivo histology image was predicted from comparison between pre and post- first debulking 4 color coded maps. Cross sectional histology slices were cut every 0.5 mm starting from the most proximal part of the formalin-fixed debulking tissue. Histology slices were divided into two groups by the presence or absence of pathological thrombus.
Results: A total of 259 in vitro histology slices were obtained and compared with the corresponding in vivo color coded map. Of these slices, pathological thrombus was detected in 81 slices. Correlation was favorable with high sensitivity for all plaque components, however, specificity and predictive accuracy for fibrous and fibro-fatty were lower in thrombus slices, as shown in table⇓.
Conclusions: Intramural thrombus was colored as fibrous or fibro-fatty by VH-IVUS, reducing the VH accuracy in these kinds of lesions.