Description:
Hypothesis The morphology of low-density non-calcified coronary plaque is associated with acute coronary syndrome (ACS) and culprit lesion precursors Methods: This was a post-hoc analysis of the multicenter ICONIC study. A subset of 94 patients suspected of coronary artery disease (CAD) underwent coronary CT angiography imaging (CCTA) with subsequent follow-up for the occurrence of the first ACS event were selected. At the time of ACS, the culprit lesion was adjudicated by invasive coronary angiography cardiologists blinded to the CCTA. Quantitative CT was performed by a validated software as a service (Cleerly Labs, Cleerly, Inc., Denver, CO). A level-III reader used multiplanar reformation (MPR) images from this analysis to qualitatively assess individual collections of low-density non-calcified (LDNC) plaques (-189 to 30 HU). The degree of embedded LDNC plaque (DELP) was the amount a LDNC plaque was surrounded by non-calcified plaque. DELP was categorized as 90, 180, 270, and 360. LDNC plaque shape was categorized as crescent, round, lobular, or bean-shaped. DELP and shape were qualitatively assessed using the cross-sectional MPR image with the greatest LDNC plaque area. LDNC plaques with >270 DELP and round or bean-shaped were considered high-risk plaque (HRP) morphology. Results: ACS occurred in 64 patients. 247 LDNC plaques were analyzed. Patients without and with ACS had, on average 0.40±0.86 and 1.02±1.21 (p-value = 0.014) LDNC plaques with HRP morphology. The proportional hazard ratio associating the presence of one or more HRP morphology plaques with ACS was 2.03 (1.19, 3.48; p-value = 0.009), after controlling for diameter stenosis, age, sex, and family history of CAD. The odds ratio of the association of HRP morphology with culprit lesion precursors was 10.93 (3.77, 31.71; p-value <0.001), after controlling for diameter stenosis, age, sex, and family history of CAD. Conclusion HRP morphology may improve the stratification of patients at risk for ACS.