Abstract 14086: Optical Coherence Tomography Analysis of Attenuated Plaques Detected by Intravascular Ultrasound in Patients With Acute Coronary Syndromes
Background. Recent intravascular ultrasound (IVUS) studies have demonstrated that hypoechoic plaque with deep ultrasound attenuation despite absence of bright calcium is common in acute coronary syndrome. Such “attenuated plaque” may be an IVUS characteristic of unstable lesion.
Methods. We used optical coherence tomography (OCT) in 104 patients with unstable angina to compare lesion characteristics between IVUS-detected attenuated plaque and non-attenuated plaque.
Results. IVUS-detected attenuated plaque was observed in 41 (39%) patients. There were no significant differences in coronary risk factors between the patients with attenuated and non-attenuated plaque. Although the frequency of Braunwald clinical class I (20% vs. 49%, p=0.002) and class II (7% vs. 29%, p=0.011) was significantly lower in the attenuated plaque group compared with the non-attenuated plaque group, the frequency of class III (73% vs. 22%, p<0.001) was significantly higher in the attenuated plaque group. In the IVUS analysis, plaque burden (78 ± 10% vs. 73 ± 9%, p=0.022) and frequency of positive remodeling (54% vs. 30%, p=0.017) was significantly greater in attenuated plaques compared with non-attenuated plaques. In the OCT analysis, the frequency of lipidic plaque (88% vs. 49%, p<0.001) was significantly higher in attenuated plaques compared with non-attenuated plaques, while the frequency of fibrocalcific plaque (12% vs. 42%, p=0.002) and fibrotic plaque (0% vs. 9%, p=0.042) was significantly lower in attenuated plaques. In the lipidic plaques, fibrous cap thickness (103 ± 70 μm vs. 145 ± 97 μm, p=0.040) was significantly thinner and lipid arc (204 ± 57 degree vs. 166 ± 48 degree, p=0.004) was significantly greater in attenuated plaques compared with non-attenuated plaques. OCT-detected TCFA (48% vs. 16%, p<0.001), plaque rupture (44% vs. 11%, p<0.001) and intracoronary thrombus (54% vs. 17%, p<0.001) was more often seen in attenuated plaques compared with non-attenuated plaques.
Conclusions. IVUS-detected attenuated plaque has many characteristics of unstable coronary lesion. The presence of attended plaque might be an important marker of lesion instability.
- © 2011 by American Heart Association, Inc.