In vivo assessment of high-risk coronary plaques at bifurcations with combined intravascular ultrasound and optical coherence tomography.
OBJECTIVE
This study sought to evaluate the in vivo frequency and distribution of high-risk plaques (i.e., necrotic core rich) at bifurcations using a combined plaque assessment with intravascular ultrasound-virtual histology (IVUS-VH) and optical coherence tomography (OCT).


BACKGROUND
Pathological examinations have shown that atherosclerotic plaque rich in necrotic core is prone to develop at bifurcations. High-risk plaque detection could be improved by the combined use of a technique able to detect necrotic core (IVUS-VH) and a high-resolution technique that allows the measurement of the fibrous cap thickness (OCT).


METHODS
From 30 patients imaged with IVUS-VH and OCT, 103 bifurcations were selected. The main branch was analyzed at the proximal rim of the ostium of the side branch, at the in-bifurcation segment and at the distal rim of the ostium of the side branch. Plaques with more than 10% confluent necrotic core by IVUS-VH were selected and classified as fibroatheroma (FA) or thin-cap fibroatheroma (TCFA) depending on the thickness of the fibrous cap by OCT (>65 or < or =65 microm for FA and TCFA, respectively).


RESULTS
Twenty-seven FA (26.2%) and 18 TCFA (17.4%) were found out of the 103 lesions studied. Overall the percentage of necrotic core decreases from proximal to distal rim (16.8% vs. 13.5% respectively, p = 0.01), whereas the cap thickness showed an inverse tendency (130 +/- 105 microm vs. 151 +/- 68 microm for proximal and distal rim, respectively, p = 0.05). The thin caps were more often located in the proximal rim (15 of 34, 44.1%), followed by the in-bifurcation segment (14 of 34, 41.2%), and were less frequent in the distal rim (5 of 34, 14.7%).


CONCLUSIONS
The proximal rim of the ostium of the side branch has been identified as a region more likely to contain thin fibrous cap and a greater proportion of necrotic core.
Gonzalo
Nieves
N
Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands.
Garcia-Garcia
Hector M
HM
Regar
Evelyn
E
Barlis
Peter
P
Wentzel
Jolanda
J
Onuma
Yoshinobu
Y
Ligthart
Jurgen
J
Serruys
Patrick W
PW
D000368:Aged; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D005355:Fibrosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D011237:Predictive Value of Tests; D018570:Risk Assessment; D041623:Tomography, Optical Coherence; D018084:Ultrasonography, Interventional