Associations of coronary artery calcified plaque density with mortality in type 2 diabetes: the Diabetes Heart Study.

BACKGROUND: Coronary artery calcified plaque (CAC) is strongly predictive of cardiovascular disease (CVD) events and mortality, both in general populations and individuals with type 2 diabetes at high risk for CVD. CAC is typically reported as an Agatston score, which is weighted for increased plaque density. However, the role of CAC density in CVD risk prediction, independently and with CAC volume, remains unclear. METHODS: We examined the role of CAC density in individuals with type 2 diabetes from the family-based Diabetes Heart Study and the African American-Diabetes Heart Study. CAC density was calculated as mass divided by volume, and associations with incident all-cause and CVD mortality [median follow-up 10.2 years European Americans (n = 902, n = 286 deceased), 5.2 years African Americans (n = 552, n = 93 deceased)] were examined using Cox proportional hazards models, independently and in models adjusted for CAC volume. RESULTS: In European Americans, CAC density, like Agatston score and volume, was consistently associated with increased risk of all-cause and CVD mortality (p ≤ 0.002) in models adjusted for age, sex, statin use, total cholesterol, HDL, systolic blood pressure, high blood pressure medication use, and current smoking. However, these associations were no longer significant when models were additionally adjusted for CAC volume. CAC density was not significantly associated with mortality, either alone or adjusted for CAC volume, in African Americans. CONCLUSIONS: CAC density is not associated with mortality independent from CAC volume in European Americans and African Americans with type 2 diabetes.

Improved Detection of Small and Low-Density Plaques in Virtual Noncontrast Imaging-based Calcium Scoring at Photon-Counting Detector CT.

Purpose To investigate the impact of plaque size and density on virtual noncontrast (VNC)-based coronary artery calcium scoring (CACS) using photon-counting detector CT and to provide safety net reconstructions for improved detection of subtle plaques in patients whose VNC-based CACS would otherwise be erroneously zero when compared with true noncontrast (TNC)-based CACS. Materials and Methods In this prospective study, CACS was evaluated in a phantom containing calcifications with different diameters (5, 3, and 1 mm) and densities (800, 400, and 200 mg/cm3) and in participants who underwent TNC and contrast-enhanced cardiac photon-counting detector CT (July 2021-March 2022). VNC images were reconstructed at different virtual monoenergetic imaging (55-80 keV) and quantum iterative reconstruction (QIR) levels (QIR,1-4). TNC scans at 70 keV with QIR off served as the reference standard. In vitro CACS was analyzed using standard settings (3.0-mm sections, kernel Qr36, 130-HU threshold). Calcification detectability and CACS of small and low-density plaques were also evaluated using 1.0-mm sections, kernel Qr44, and 120- or 110-HU thresholds. Safety net reconstructions were defined based on background Agatston scores and evaluated in vivo in TNC plaques initially nondetectable using standard VNC reconstructions. Results The in vivo cohort included 63 participants (57.8 years ± 15.5 [SD]; 37 [59%] male, 26 [41%] female). Correlation and agreement between standard CACSVNC and CACSTNC were higher in large- and medium-sized and high- and medium-density than in low-density plaques (in vitro: intraclass correlation coefficient [ICC] ≥ 0.90; r > 0.9 vs ICC = 0.20-0.48; r = 0.5-0.6). Small plaques were not detectable using standard VNC reconstructions. Calcification detectability was highest using 1.0-mm sections, kernel Qr44, 120- and 110-HU thresholds, and QIR level of 2 or less VNC reconstructions. Compared with standard VNC, using safety net reconstructions (55 keV, QIR 2, 110-HU threshold) for in vivo subtle plaque detection led to higher detection (increased by 89% [50 of 56]) and improved correlation and agreement of CACSVNC with CACSTNC (in vivo: ICC = 0.51-0.61; r = 0.6). Conclusion Compared with TNC-based calcium scoring, VNC-based calcium scoring was limited for small and low-density plaques but improved using safety net reconstructions, which may be particularly useful in patients with low calcium scores who would otherwise be treated based on potentially false-negative results. Keywords: Coronary Artery Calcium CT, Photon-Counting Detector CT, Virtual Noncontrast, Plaque Size, Plaque Density Supplemental material is available for this article. © RSNA, 2024.

Is plasma-soluble CD36 associated with density of atheromatous plaque and ankle-brachial index in early-onset coronary artery disease patients?

BACKGROUND: CD36 is a major macrophage scavenger receptor for oxidised low-density lipoprotein particles. Soluble CD36 (sCD36) is circulating as a ligand-bound complex and may be present in microparticles shed from cells such as platelets, monocytes/macrophages, or adipocytes. Positive association of plasma sCD36 with insulin resistance has been reported, and it has been proposed that sCD36 might represent a marker of macrophage activation and inflammation leading to atherosclerosis. Recently we have identified an association between CD36 polymorphism and low thickness of atheromatous plaque, suggesting its protective effect against atherosclerosis development. AIM: To obtain insight into the relationship between plasma concentration of sCD36 and radiological parameters of atherosclerosis in patients with early-onset coronary artery disease (CAD). METHODS: The study group comprised 70 clinically stable patients (18 women and 52 men) with early CAD (aged no more than 50 years for men and 55 years for women). Fasting blood sample was taken for serum glucose, lipid profile, ApoA1, ApoB, Lp(a), and plasma sCD36 protein measurements. Each subject's weight, height, waist and hip circumference, and systolic and diastolic blood pressure were measured, and the body mass index, waist-to-hip ratio, and mean arterial pressure were calculated. Doppler ultrasound examinations of carotid and peripheral arteries were performed in all patients. Thickness of intima-media complex (IMC) of common carotid (CCA) and brachial arteries, as well as density and thickness of atheromatous plaque at CCA bifurcation, were measured with M'Ath programme. Plasma concentrations of CD36 antigen were measured by ELISA. Correlations between quantitative variables and sCD36 plasma concentration were assessed with the Spearman rank correlation coefficient (Rs). Associations between qualitative variables and sCD36 plasma concentration were tested with the Mann-Whitney U test. RESULTS: We observed no significant correlations between sCD36 concentration and radiological parameters of atherosclerosis. We found only borderline significant negative correlation of sCD36 concentration with thickness of IMC of left brachial artery. We also observed a significantly negative correlation with CCA plaque density, but only in the female subgroup and on the right side. Borderline higher sCD36 plasma concentrations were observed in patients with lower ankle-brachial index value (< 0.9). CONCLUSIONS: The results of the study show no strong associations and do not prove either detrimental or beneficial influence of sCD36 on radiological parameters of atherosclerosis. Further research is necessary to assess the association of high plasma sCD36 concentrations with the risk of plaque instability in patients with early-onset CAD.