Direct Comparison of Virtual-Histology Intravascular Ultrasound and Optical Coherence Tomography Imaging for Identification of Thin-Cap Fibroatheroma.

ABSTRACT: BACKGROUND:Although rupture of thin-cap fibroatheroma (TCFA) underlies most myocardial infarctions, reliable TCFA identification remains challenging. Virtual-histology intravascular ultrasound (VH-IVUS) and optical coherence tomography (OCT) can assess tissue composition and classify plaques. However, direct comparisons between VH-IVUS and OCT are lacking and it remains unknown whether combining these modalities improves TCFA identification. METHODS AND RESULTS:Two hundred fifty-eight regions-of-interest were obtained from autopsied human hearts, with plaque composition and classification assessed by histology and compared with coregistered ex vivo VH-IVUS and OCT. Sixty-seven regions-of-interest were classified as fibroatheroma on histology, with 22 meeting criteria for TCFA. On VH-IVUS, plaque (10.91±4.82 versus 8.42±4.57 mm(2); P=0.01) and necrotic core areas (1.59±0.99 versus 1.03±0.85 mm(2); P=0.02) were increased in TCFA versus other fibroatheroma. On OCT, although minimal fibrous cap thickness was similar (71.8±44.1 ?m versus 72.6±32.4; P=0.30), the number of continuous frames with fibrous cap thickness ?85 ?m was higher in TCFA (6.5 [1.75-11.0] versus 2.0 [0.0-7.0]; P=0.03). Maximum lipid arc on OCT was an excellent discriminator of fibroatheroma (area under the curve, 0.92; 95% confidence interval, 0.87-0.97) and TCFA (area under the curve, 0.86; 95% confidence interval, 0.81-0.92), with lipid arc ?80° the optimal cut-off value. Using existing criteria, the sensitivity, specificity, and diagnostic accuracy for TCFA identification was 63.6%, 78.1%, and 76.5% for VH-IVUS and 72.7%, 79.8%, and 79.0% for OCT. Combining VH-defined fibroatheroma and fibrous cap thickness ?85 ?m over 3 continuous frames improved TCFA identification, with diagnostic accuracy of 89.0%. CONCLUSIONS:Both VH-IVUS and OCT can reliably identify TCFA, although OCT accuracy may be improved using lipid arc ?80° and fibrous cap thickness ?85 ?m over 3 continuous frames. Combined VH-IVUS/OCT imaging markedly improved TCFA identification.

SUBMITTER: Brown AJ 

PROVIDER: S-EPMC4596008 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature