Abstract 340: A Few but Nonnegligible Patients Without Any Coronary Calcification Had CT-based Vulnerable Plaque
Background: Although coronary artery calcium is an important prognostic indicator of coronary events, plaque characteristics including positive remodeling and lipid richness determine the vulnerability of plaques to rupture. Severity of luminal stenosis is not associated with adverse events. The present study was performed to evaluate coronary plaques in patients without any coronary calcification.
Methods: 4884 consecutive patients underwent coronary CTCA (Toshiba, Aquilion 64) at our Center. Of these, 3404 patients with no history of previous myocardial infarction (MI) or intervention (PCI) were divided into coronary calcification (Ca group, n=2010) and non-calcific (No-Ca, n=1394) patient groups. Definition of CT-based “Vulnerable Plaque” on CTCA was to fulfill the exist of “positive remodeling” and “≤50HU CT value”.
Results: Ca group included 0 vessel disease (0-VD, plaques is present, but no significant stenosis) (n=1324), 1-VD (425), 2-VD (190), 3-VD (68); No-Ca group included patients with normal vessels (n=938), 0-VD (423), 1-VD (27), 2-VD (6). In Ca-group, Age(P<0.0001), BPs(P<0.0001) and10-year risk (P<0.0001) were significantly higher than No-Ca group. In Non-Calc group, 10-year risk (P<0.0001) and mean PWV (P=0.007) of patients with significant stenosis (N=33) were significantly higher and HDL lower (P=0.0453) than patients without significant stenosis. 33 (2.4%) of 1394 patients in No-Ca group had significant stenosis and 17 lesions in 15 patients of them were defined as vulnerable plaque. Therefore 67 lesions in 60 of 423 patients with 0-VD in No-Ca group were also defined as vulnerable plaques. Their mean minimum plaque attenuation of vulnerable plaque was 21±20HU. Totally, 75 (5.4%) patients in No-Ca group had 84 vulnerable plaques.
Conclusions: 2.4% of patients in No-Ca group demonstrated significant luminal stenosis, and 5.4% of patients in No-Ca group had CT-based unstable lesions.