Abstract 16533: Carotid Vasa Vasorum Density Measured in vivo by Contrast-Enhanced Ultrasound is Associated with Acute Coronary Events

Abstract

Background: Coronary artery adventitial vasa vasorum (VV) proliferation is a feature of the “vulnerable” plaques (VP) that cause acute coronary syndromes (ACS). Carotid contrast enhanced ultrasound (CEUS) visualizes VV proliferation in vivo, which is associated with greater stroke risk. The specific association of CEUS carotid VV proliferation and coronary VP is unknown. We hypothesized that CEUS carotid VV density is greater in patients with coronary VP as defined by recent myocardial infarction (MI), compared to those with stable or no coronary artery disease (CAD).

Methods: Bilateral CEUS was performed in a cross-sectional, observational study of 3 groups of patients referred for cardiac catheterization (n=66): 1) Acute MI within 15 days (n=18); 2) Stable CAD (n=31) by angiography (>50% stenosis) but no ACS in past 3 months; and 3) No angiographic CAD (n=17). VV density was quantified as video intensity in adventitial regions of interest normalized to luminal video intensity. Two observers analyzed the first 32 subjects to derive inter-rater Spearman correlation. ANOVA and chi squared tests were used to assess associations and adjust for covariates.

Results: Subjects were mostly male (70%), mean age 59.9± 9.2 yrs. Spearman correlation coefficient (0.76) showed good interobserver image analysis reliability. VV density was higher in subjects with recent MI (0.131±0.056) than those with stable CAD (0.065±0.054, p<0.001), and those with no CAD (0.045±0.038, p<0.001), despite similar angiographic CAD severity between the Acute MI and Stable CAD groups (p=0.58). Compared to Stable CAD subjects, those with Acute MI were more likely to be smokers (p<0.001) and less likely to be on a statin (p=0.001). Acute MI and Stable CAD carotid VV density differences remained after adjusting for active smoking, statin or aspirin use, and dyslipidemia (0.045; 95% CI: 0.002-0.088).

Conclusion: Adventitial carotid artery VV density is greater in patients with recent ACS compared to those with stable CAD. These data suggest that despite comparable atherosclerotic burden in the groups with Acute MI and Stable CAD, the presence of carotid adventitial VV proliferation specifically discriminates presence of coronary VP, and confirms the value of CEUS for ACS risk prediction.