Abstract Background Percutaneous coronary intervention (PCI) has improved outcomes for culprit lesions in patients with acute coronary syndrome (ACS). However, the incidence of major adverse cardiovascular events in non-culprit lesions remains high, highlighting the importance of early detection of unstable plaques. Purpose This study aimed to compare the plaque characteristics of non-culprit lesions in patients with ACS and chronic coronary syndrome (CCS) using coronary computed tomography angiography (CCTA). The primary objective was to evaluate the characteristics of non-culprit lesions in ACS patients on CCTA. Methods A total of 88 non-culprit lesions from 37 patients (20 with ACS and 17 with CCS) who underwent PCI between April 2024 and February 2025 were analyzed using CCTA. Morphometric analysis and plaque volume measurements were performed using SYNAPSE VINCENT. Soft plaques were classified into two types—protrusion type and smooth type—based on their morphological characteristics. Protrusion type was defined as a soft plaque extending into the lumen, whereas smooth type was defined as either the absence of soft plaque or the presence of a soft plaque that did not extend into the lumen. Results Patients in the ACS group were significantly younger and had a higher prevalence of hyperuricemia. In contrast, patients in the CCS group had a significantly higher prevalence of diabetes mellitus and chronic kidney disease. Lesion characteristics, including lesion length, stenosis percentage, and minimum lumen area, were similar between the two groups. The percentage of soft plaque volume was significantly larger in the ACS group compared to the CCS group (13.3% IQR 10.9%-16.0% vs. 12.2% IQR 8.2%-14.4%, p = 0.02). Additionally, protrusion type plaques were significantly more common in the ACS group (68.4% vs. 23.3%, p = 0.0002). In contrast, the percentage of calcified plaque volume was significantly lower in the ACS group (3.0% IQR 0.4%-11.1% vs. 16.8% IQR 3.1%-29.4%, p = 0.005). Multivariable logistic regression analysis demonstrated that ACS was significantly associated with protrusion type plaques (OR: 4.4; 95% CI: 1.4–13.4; p = 0.01). Conclusion Non-culprit lesions in ACS patients exhibited a larger soft plaque volume and a higher prevalence of protrusion type plaques. The presence of protrusion type plaques in non-culprit lesions on CCTA was strongly associated with ACS and may serve as an indicator of unstable plaques. CCTA may be a useful modality for evaluating soft plaque morphology in non-culprit lesions.
Kato et al. (2025) studied this question.