Comparison of Coronary Artery Calcium and Quantitative Coronary Plaque in Predicting Obstructive Coronary Artery Disease: Subgroup Analysis of the CLARIFY Study.

Background: Agatston coronary artery calcium (CAC) score is a strong predictor of mortality. However, the relationship between CAC and quantitative calcified plaque volume (CPV), which is measured on coronary computed tomography angiography (CCTA), is not well understood. Furthermore, there is limited evidence evaluating the difference between CAC versus CPV and CAC versus total plaque volume (TPV) in predicting obstructive coronary artery disease (CAD). Methods: This study included 147 subjects from the CLARIFY registry, a multicentered study of patients undergoing assessment using CCTA and CAC score as part of acute and stable chest pain evaluation. Automated software service (Cleerly.Inc, Denver, CO, USA) was used to evaluate the degree of vessel stenosis and plaque quantification on CCTA. CAC was measured using the standard Agatston method. Spearman correlation and receiver operating characteristic curve analysis was performed to evaluate the diagnostic ability of CAC, CPV and TPV in detecting obstructive CAD. Results: Results demonstrated a very strong positive correlation between CAC and CPV (r=0.76, p=0.0001) and strong correlation between CAC and TPV (r=0.72, p<0.001) at per-patient level analysis. At per-patient level analysis, the sensitivity of CAC (68%) is lower than CPV (77%) in predicting >50% stenosis, but negative predictive value is comparable. However, the sensitivity of TPV is higher compared with CAC in predicting >50% stenosis, and the negative predictive value of TPV is also higher. Conclusion: CPV and TPV are more sensitive in predicting the severity of obstructive CAD compared with the CAC score. However, the negative predictive value of CAC is comparable to CPV, but is lower than TPV. This study elucidates the relationship between CAC and quantitative plaque types, and especially emphasizes the differences between CAC and CPV which are two distinct plaque measurement techniques that are utilized in predicting obstructive CAD.

Association between coronary artery calcium and thoracic spine bone mineral density: Multiethnic Study of Atherosclerosis (MESA).

BACKGROUND AND AIMS: Previously, osteoporosis and coronary artery disease were considered unrelated. However, beyond age, these two conditions appear to share common etiologies that are not yet fully understood. We examined the relationship between thoracic spine bone mineral density (BMD) and severity of coronary artery calcium (CAC) score. METHODS AND RESULTS: MESA is a prospective cohort study of 6814 men and women between the ages of 45 and 84 years, without clinical cardiovascular disease. This study included participants who underwent non-contrast chest CT scans to determine CAC score and thoracic spine BMD. The thoracic spine BMD was categorized into osteoporosis (defined as T score: ≤ -2.5), osteopenia (T-score between: -2.5 and -1) and normal BMD (T-score ≥ -1). There were 3392 subjects who had CAC >0 at baseline. The prevalence of CAC >0 was 36% in normal BMD group, 49% in the osteopenia and 68% in osteoporosis group. After adjusting for risk factors of atherosclerosis, in multivariate regression models we found a significant association between CAC and osteoporosis (OR: 1.40, 95% CI 1.16-1.69, p value < 0.0004). Furthermore, we stratified our results by gender and found a statistically significant association in both men and women. CONCLUSION: Results from this cross-sectional analysis of a large population based ethnically diverse cohort indicate a significant inverse relationship between thoracic BMD and CAC in both genders independent of other cardiovascular risk factors. Future studies need to explore the underlying pathophysiological mechanisms relating BMD and coronary artery calcification.

Association of flow mediated vasodilation and burden of subclinical atherosclerosis by coronary CTA.

BACKGROUND AND AIMS: Endothelial dysfunction and atherosclerosis are linked by multiple mechanisms. Brachial artery flow-mediated dilation (FMD) rate is used to evaluate endothelial function and has been independently associated with adverse cardiac outcomes. The relationship between brachial artery FMD rate and severity of subclinical atherosclerosis by coronary computed tomography angiography (CCTA) is not understood. We hypothesized that brachial FMD is inversely associated with burden of subclinical atherosclerosis measured by CCTA. METHODS: This is a retrospective study of 100 participants with intermediate cardiac risk and atypical symptoms to examine association between brachial artery FMD rate and surrogate markers of severity of subclinical atherosclerosis on CCTA. Multivariate linear regression analysis was used to understand the relationship between brachial artery FMD rate and markers of plaque burden on CCTA including coronary artery calcium (CAC) score, segment involvement score (SIS; total number of segments with any plaque), segment stenosis score (SSS, sum of maximal stenosis score per segment), and total plaque score (TPS, the sum of all segments plaque burden). RESULTS: 52 participants (42%) were female. Mean age of the cohort was 59.3 ± 10.4 years. After adjusting for traditional risk factors, brachial artery FMD rate was inversely associated with higher CAC, TPS, SIS and SSS (p < 0.05 for all). FMD <4.5 predicted the presence of CAC >0 and ≤ 100 most effectively, with a sensitivity of 62.2% and a specificity of 66.7%, respectively (area under the curve (AUC) of 0.5729, p = 0.0302). FMD <2.7 predicted the presence of CAC >100 most effectively, with a sensitivity of 34% and a specificity of 83% respectively (AUC of 0.6226, p = 0.0095). CONCLUSIONS: Brachial FMD is independently associated with the presence and extent of subclinical atherosclerosis on CCTA. Our findings provide more detailed evidence that mechanistically, FMD, a surrogate marker of systemic endothelial dysfunction is a correlate of atherosclerotic burden, assessed by CCTA and CAC.

Cardiovascular risk factors and mitral annular calcification in type 2 diabetes.

OBJECTIVE: Mitral annular calcification (MAC) is a degenerative process of the mitral annulus associated with cardiac disease and stroke. Although thought to be more prevalent in type 2 diabetes (T2DM), MAC remains poorly characterized in this population, due to confounding by renal and cardiac disease. Our goal was to study the risk factors for MAC in a sample of T2DM subjects without renal and cardiac disease. METHODS: The Penn Diabetes Heart Study (PDHS) is a cross-sectional study of diabetic individuals without clinical cardiovascular or renal disease. We quantified and analyzed MAC Agatston scores in baseline cardiac CTs from 1753 individuals. Logistic and tobit regression were used to assess MAC's relationship with risk factors and coronary artery calcium (CAC). RESULTS: MAC was present in 12.0% of subjects, with a median Agatston score of 72.3 [Interquartile range (22.2-256.9)]. Older age, female gender, Caucasian race, and longer diabetes duration were independently associated with both the presence and extent MAC even after controlling for CAC; however, hypertension, hyperlipidemia, tobacco use, CRP levels, and other comorbidities were not associated. CAC was strongly associated with MAC [OR of 4.0 (95% CI 2.4-6.6)] in multivariable models. CONCLUSIONS: Age, female gender, Caucasian race, and diabetes duration were associated with the presence and extent of MAC in T2DM subjects, independent of CAC, which was also strongly associated with MAC. These data suggest that additional mechanisms for MAC formation in diabetics may exist which are distinct from those related to generalized atherosclerosis and deserve further investigation.

A meandering mesenteric artery.

An 83-year-old woman with a history of peripheral vascular disease presented for evaluation of lower left extremity discomfort. A peripheral multidetector CT angiography showed a dilated inferior mesenteric artery acting as an important source of retrograde collateral perfusion secondary to a celiac axis stenosis.