Objective: We aimed to use multi-slice computed to-mography angiography (CTA) for assessment of mor-phological characteristics of culprit lesions producing an ACS in the next several months after CT assessment, in comparison with morphological characteristics of unstable coronary atherosclerotic plaques which did not trigger an ACS.
Methods: We analyzed 40 patients in whom CTA reve-aled presence of unstable coronary lesions, exhibiting at least one marker of vulnerability: napkin ring sign (NRS), spotty calcium (SC), positive remodeling (PR) or presence of low attenuation plaque (LAP), divided in 2 groups: group 1 – 20 patients who developed an ACS in the next 6 months following CTA examination, and group 2 – 20 patients matched for age, gender and risk factors, who did not present any cardiovascular event 6 month after CTA assessment. Post-processing of mul-ti-slice CTA images was performed in order to assess morphological characteristics and CT-derived markers of atherosclerotic plaque instability.
Results: Similar mean values of plaque length (17.1 +/-5.9 mm vs 16.9 +/- 3.4 mm; p=0.6) and total atheroma volume (188.1 +/- 104.7 mm3 vs. 186.4 +/- 90.7 mm3; p=0.8) were obtained for both groups. The mean num-ber of vulnerability markers was 1.6 in group 1 vs. 1.2 in group 2 (p=0.07). However, atherosclerotic lesions in patients from group 1 presented significantly higher values of lipid-rich atheroma (9.8 +/- 10.8 mm3 vs. 2.6 +/- 1.0 mm3; p=0.01) and remodeling index (1.14 +/-0.3 in group 1 vs. 0.89 +/- 0.19 in group 2, p=0.04). At the same time, atheromatous plaques in patients who developed an ACS during the 6-months follow-up showed in a significantly higher proportion LAP (45% in group vs. 10% in group 2, p=0.03) and PR (15% in group 1 vs 5% in group 2, p=0.04), but not NRS (30% vs. 25%, p=ns) or SC (65% vs. 40%, p=0.2).
Conclusions: Atherosclerotic plaques producing an ACS exhibit a different phenotype than unstable plaqu-es that remain silent. The CTA profile of atheromatous plaques producing an ACS includes the presence of low attenuation, positive remodeling, higher RI and lipid-rich atheroma. Presence of these features in high-risk coronary plaques identifies very high-risk patients, who can benefit from adapted therapeutic strategy in order to prevent the development of an ACS.