Computed Tomography Coronary Angiography Possibilities in “High Risk” Plaque Identification in Patients with non-ST-Elevation Acute Coronary Syndrome: Comparison with Intravascular Ultrasound

Abstract

Aim To evaluate structural characteristics of atherosclerotic plaques (ASP) by coronary computed tomography arteriography (CCTA) and intravascular ultrasound (IVUS).Material and methods This study included 37 patients with acute coronary syndrome (ACS). 64-detector-row CCTA, coronarography, and grayscale IVUS were performed prior to coronary stenting. The ASP length and burden, remodeling index (RI), and known CT signs of unstable ASP (presence of dot calcification, positive remodeling of the artery in the ASP area, irregular plaque contour, presence of a peripheral high-density ring and a low-density patch in the ASP). The ASP type and signs of rupture or thrombosis were determined by IVUS.Results The IVUS study revealed 45 unstable ASP (UASP), including 25 UASP with rupture and 20 thin-cap fibroatheromas (TCFA), and 13 stable ASP (SASP). No significant differences were found between distribution of TCFA and ASP with rupture among symptom-associated plaques (SAP, n=28) and non-symptom-associated plaques (NSAP, n=30). They were found in 82.1 and 73.3 % of cases, respectively (p>0.05), which indicated generalization of the ASP destabilization process in the coronary circulation. However, the incidence of mural thrombus was higher for SAP (53.5 and 16.6 % of ASP, respectively; p<0.001). There was no difference between UASP and SASP in the incidence of qualitative ASP characteristics or in values of quantitative ASP characteristics, including known signs of instability, except for the irregular contour, which was observed in 92.9 % of UASP and 46.1 % of SASP (p=0.0007), and patches with X-ray density ≤46 HU, which were detected in 83.3 % of UASP and 46.1 % of SASP (р=0.01). The presence of these CT criteria 11- and 7-fold increased the likelihood of unstable ASP (odd ratio (OR), 11.1 at 95 % confidence interval (CI), from 2.24 to 55.33 and OR, 7.0 at 95 % CI, from 5.63 to 8.37 for the former and the latter criterion, respectively).Conclusion According to IVUS data, two X-ray signs are most characteristic for UASP, the irregular contour and a patch with X-ray density ≤46 HU. The presence of these signs 11- and 7-fold, respectively, increases the likelihood of unstable ASP.

Coronary Artery Characteristics by Volume Computed Tomography in Patients With Acute Coronary Syndrome

“…Участком низкой плотности принимали область бляшки с плотностью <46 HU в соответствии с данными отечественной литературы [10] (рис. 2).…”

“…Сравнение степени стенозирования коронарных артерий по результатам объемной КТ и КАГ у пациентов с ОКС. ференцировки стабильных и нестабильных бляшек, поэтому и был использован в настоящем исследовании [10]. Зарубежные авторы наиболее часто выбирают границу в 30 HU [20], однако встречаются исследования с более высокими пороговыми рентгеновскими плотностями [21].…”

“…Редким признаком нестабильности, выявленным в нашей работе, была неровность контура АСБ. Данный признак встречается преимущественно в симптомсвязанных артериях и отображает непосредственно надрыв бляшки [10,22]. А так как в нашем исследовании анализировали симптом-несвязанные участки коронарного русла, соответственно, неровность контура бляшки была нечастой находкой.…”