Background
Although attenuated plaque is a marker for plaque vulnerability, the quantification and its implication have not been known.
Methods
Multimodality pre‐procedural imaging using grayscale intravascular ultrasound (IVUS), virtual histology‐IVUS (VH‐IVUS), and optical coherence tomography (OCT) were performed in 115 coronary lesions with diameter stenosis (DS) >30% and plaque burden ≥50% and compared the diagnostic accuracies for detecting thin‐cap fibroatheromas (TCFA).
Results
A maximal arc of attenuation (40 MHz IVUS) ≥29.0° was the cutoff for predicting VH‐TCFA (sensitivity 74%, specificity 66%); and OCT‐TCFA (sensitivity 89%, specificity 64%), while a maximal arc attenuation ≥29.0° (20MHz IVUS) showed a poor sensitivity for predicting TCFA. Compared to the lesions with an arc of attenuation <30° as a rough cutoff value, the lesions with a maximum arc of attenuation ≥30° (40 MHz) were associated with more severe (smaller angiographic minimum lumen diameter and greater DS, smaller IVUS‐MLA and a larger plaque burden) and had more unstable lesion characteristics: (1) larger remodeling index and more plaque ruptures (grayscale IVUS); (2) greater %necrotic core and more VH‐TCFAs (VH‐IVUS); and (3) more lipid, macrophages, cholesterol crystals, and microchannels; thinner fibrous caps; and more OCT‐TCFAs, OCT‐detected plaque ruptures, and red and white thrombi (OCT). Among 58 patients treated with stent implantation, postintervention peak CK‐MB was higher in patients with the maximal attenuation ≥30° compared to those without (median 2.7 ng/ml [IQR 0.9–18.7 ng/ml] vs. median 0.9 ng/ml [IQR 0.7–2.1 ng/ml], P = 0.012).
Conclusion
Attenuated plaque with a maximal attenuation ≥30° vs. <30° (40 MHz, but not 20 MHz IVUS) were more likely to be associated with unstable lesion morphology that may contribute to the immediate poststenting CK‐MB elevation. © 2016 Wiley Periodicals, Inc.