Plaque Characterization by Coronary Computed Tomography Angiography and the Likelihood of Acute Coronary Events in Mid-Term Follow-Up

Background: Coronary computed tomography angiography (CTA)-verified positive remodeling and low attenuation plaques are considered morphological characteristics of high-risk plaque (HRP) and predict short-term risk of acute coronary syndrome (ACS).

Objectives: This study evaluated whether plaque characteristics by CTA predict mid-term likelihood of ACS.

Methods: The presence of HRP and significant stenosis (SS) of ≥70% were evaluated in 3,158 patients undergoing CTA. Serial CTA was performed in 449 patients, and plaque progression (PP) was evaluated. Outcomes (fatal and nonfatal ACS) were recorded during follow-up (mean 3.9 ± 2.4 years).

Results: ACS occurred in 88 (2.8%) patients: 48 (16.3%) of 294 HRP(+) and 40 (1.4%) of 2,864 HRP(-) patients. ACS was also significantly more frequent in SS(+) (36 of 659; 5.5%) than SS(-) patients (52 of 2,499; 2.1%). HRP(+)/SS(+) (19%) and HRP(+)/SS(-) (15%) had higher rates of ACS compared with no-plaque patients (0.6%). Although ACS incidence was relatively low in HRP(-) patients, the cumulative number of patients with ACS developing from HRP(-) lesions (n = 43) was similar to ACS patients with HRP(+) lesions (n = 45). In patients with serial CTA, PP also was an independent predictor of ACS, with HRP (27%; p < 0.0001) and without HRP (10%) compared with HRP(-)/PP(-) patients (0.3%).

Conclusions: CTA-verified HRP was an independent predictor of ACS. However, the cumulative number of ACS patients with HRP(-) was similar to patients with HRP(+). Additionally, plaque progression detected by serial CTA was an independent predictor of ACS.