COVID-19 IgG/IgM antibody testing in Los Angeles County, California.

Evidence suggests that asymptomatic and mild SARS-CoV-2 infections comprise > 95% of all cases. Developing a test that indicates past infection and possible immunity against the virus is important. We administered 244 antibody tests to three groups of high-risk population. The test consisted of an IgG component and an IgM component. The overall IgM/IgG positivity for patients with none, mild, moderate, and severe symptoms were 21.1%, 21.8%, 14.2%, and 26.9%, respectively. Those with moderate or severe symptoms were no more or less likely to have positive antibody tests than those with no or mild symptoms.

Apixaban versus warfarin in evaluation of progression of atherosclerotic and calcified plaques (prospective randomized trial).

Warfarin has been showed to increase vascular calcification. Apixaban, a direct factor Xa inhibitor, has no interaction with vitamin K and its effect on coronary plaques is unknown. We randomized and compared warfarin and apixaban on progression of coronary atherosclerotic plaques measured by coronary computed tomographic angiography in 66 subjects with non-valvular atrial fibrillation over the period of one-year follow up. There was significant higher total, calcified and low attenuation plaque volume in the group randomized to warfarin as compared to apixaban (all P < .05). Greater volume of total (ß2 = 28.54; P = .03), low attenuation plaque (ß2 = 3.58; P = .02) and calcified (ß2 = 14.10; P = .005) plaque progression was observed in the VKA_group.

Automated estimation of image quality for coronary computed tomographic angiography using machine learning.

OBJECTIVES: Our goal was to evaluate the efficacy of a fully automated method for assessing the image quality (IQ) of coronary computed tomography angiography (CCTA). METHODS: The machine learning method was trained using 75 CCTA studies by mapping features (noise, contrast, misregistration scores, and un-interpretability index) to an IQ score based on manual ground truth data. The automated method was validated on a set of 50 CCTA studies and subsequently tested on a new set of 172 CCTA studies against visual IQ scores on a 5-point Likert scale. RESULTS: The area under the curve in the validation set was 0.96. In the 172 CCTA studies, our method yielded a Cohen's kappa statistic for the agreement between automated and visual IQ assessment of 0.67 (p < 0.01). In the group where good to excellent (n = 163), fair (n = 6), and poor visual IQ scores (n = 3) were graded, 155, 5, and 2 of the patients received an automated IQ score > 50 %, respectively. CONCLUSION: Fully automated assessment of the IQ of CCTA data sets by machine learning was reproducible and provided similar results compared with visual analysis within the limits of inter-operator variability. KEY POINTS: • The proposed method enables automated and reproducible image quality assessment. • Machine learning and visual assessments yielded comparable estimates of image quality. • Automated assessment potentially allows for more standardised image quality. • Image quality assessment enables standardization of clinical trial results across different datasets.

Aged Garlic Extract Reduces Low Attenuation Plaque in Coronary Arteries of Patients with Metabolic Syndrome in a Prospective Randomized Double-Blind Study.

BACKGROUND: Although several previous studies have demonstrated that aged garlic extract (AGE) inhibits the progression of coronary artery calcification, its effect on noncalcified plaque (NCP) has been unclear. OBJECTIVE: This study investigated whether AGE reduces coronary plaque volume measured by cardiac computed tomography angiography (CCTA) in patients with metabolic syndrome (MetS). METHODS: Fifty-five patients with MetS (mean ± SD age: 58.7 ± 6.7 y; 71% men) were prospectively assigned to consume 2400 mg AGE/d (27 patients) or placebo (28 patients) orally. Both groups underwent CCTA at baseline and follow-up 354 ± 41 d apart. Coronary plaque volume, including total plaque volume (TPV), dense calcium (DC), NCP, and low-attenuation plaque (LAP), were measured based upon predefined intensity cutoff values. Multivariable linear regression analysis, adjusted for age, gender, number of risk factors, hyperlipidemia medications, history of coronary artery disease, scan interval time, and baseline %TPV, was performed to examine whether AGE affected each plaque change. RESULTS: The %LAP change was significantly reduced in the AGE group compared with the placebo group (-1.5% ± 2.3% compared with 0.2% ± 2.0%, P = 0.0049). In contrast, no difference was observed in %TPV change (0.3% ± 3.3% compared with 1.6% ± 3.0%, P = 0.13), %NCP change (0.2% ± 3.3% compared with 1.4% ± 2.9%, P = 0.14), and %DC change (0.2% ± 1.4%, compared with 0.2% ± 1.7%, P = 0.99). Multivariable linear regression analysis found a beneficial effect of AGE on %LAP regression (ß: -1.61; 95% CI: -2.79, -0.43; P = 0.008). CONCLUSIONS: This study indicates that the %LAP change was significantly greater in the AGE group than in the placebo group. Further studies are needed to evaluate whether AGE has the ability to stabilize vulnerable plaque and decrease adverse cardiovascular events. This trial was registered at clinicaltrials.gov as NCT01534910.

Measurement of phantomless thoracic bone mineral density on coronary artery calcium CT scans acquired with various CT scanner models.

PURPOSE: To determine the accuracy and precision of thoracic phantomless bone mineral density (BMD) measurements obtained on coronary artery calcium (CAC) computed tomography (CT) scans by using a variety of commercially available CT scanners. MATERIALS AND METHODS: The institutional review board approved this Health Insurance Portability and Accountability Act-compliant study. A total of 4126 asymptomatic subjects (2022 [49%] men, 2104 [51%] women; mean age, 63.7 years ± 11.8 [standard deviation]) underwent CAC CT with the use of a quantitative CT calibration phantom for evaluation of subclinical atherosclerosis. Two hundred eighty subjects also underwent CT of the chest, abdomen, and pelvis (C7 through L5). Mean BMD of three consecutive thoracic vertebrae (in the T7-T10 range) was measured in all 4126 subjects. Individual calibration factors for each phantom insert and a general calibration factor for the spine were determined for each CT scanner model. The study population was then divided into three subgroups: All calibration factors were generated from group 1 (n = 1536) and were applied and tested in group 2 (n = 1587), and effects of various image acquisition parameters were assessed in group 3 (n = 1003). Accuracy (bias) and precision of thoracic phantomless BMD measurements across 14 CT scanner models from five manufacturers were determined. RESULTS: Phantomless BMD values correlated highly with standard phantom-based quantitative CT BMD values (r = 0.987, P < .001). Bias was 3.9% ± 1.4 for phantomless BMD measurements, and the mean coefficient of variation for the general calibration factor was 4.9% ± 2.4. CONCLUSION: Phantomless BMD can be measured accurately on CAC CT scans acquired with a variety of CT scanners without additional radiation exposure.

Serum Thyrotropin Elevation and Coronary Artery Calcification in Hemodialysis Patients.

INTRODUCTION: Hypothyroidism is highly prevalent in end-stage kidney disease patients, and emerging data show that lower circulating thyroid hormone levels lead to downregulation of vascular calcification inhibitors and coronary artery calcification (CAC) in this population. To date, no studies have examined the association of serum thyrotropin (TSH), the most sensitive and specific single biochemical metric of thyroid function, with CAC risk in hemodialysis patients. METHODS: In secondary analyses of patients from the Anti-Inflammatory and Anti-Oxidative Nutrition in Hypoalbuminemic Dialysis Patients trial, we examined serum TSH levels and CAC risk assessed by cardiac computed tomography scans collected within a 90-day period. We evaluated the relationship between serum TSH with CAC Volume (VS) and Agatston score (AS) (defined as >100 mm3 and >100 Houndsfield Units, respectively) using multivariable logistic regression. RESULTS: Among 104 patients who met eligibility criteria, higher TSH levels in the highest tertile were associated with moderately elevated CAC VS and AS in case-mix-adjusted analyses (ref: lowest tertile): adjusted ORs (95% CIs) 4.26 (1.18, 15.40) and 5.53 (1.44, 21.30), respectively. TSH levels >3.0 mIU/L (ref: ≤3.0 mIU/L) were also associated with moderately elevated CAC VS and AS. In secondary analyses, point estimates of incrementally lower direct free thyroxine levels trended toward elevated CAC VS and AS, although associations did not achieve statistical significance. CONCLUSIONS: In hemodialysis patients, higher serum TSH was associated with elevated CAC VS and AS. Further studies are needed to determine if thyroid hormone supplementation can attenuate CAC burden in this population.

Coronary computed tomography angiography evaluation of plaque morphology and its relationship to HDL and total cholesterol to HDL ratio.

BACKGROUND: While population studies have demonstrated that high density lipoprotein cholesterol (HDL-C) and the ratio of total cholesterol to HDL (TC/HDL) improve cardiovascular risk prediction, the mechanism by which these parameters protect the cardiovascular system remains uncertain. OBJECTIVE: To investigate the relationship between the HDL-C level and the total cholesterol to HDL (TC/HDL) ratio with the morphology of coronary artery plaque as determined by coronary computed tomography angiography (CCTA). METHODS: This is a cross-sectional study involving 190 subjects with stable coronary artery disease. Semi-automated plaque analysis software was utilized to quantify plaque and plaque volumes are presented as total atheroma volume normalized (TAVnorm). Multivariate regression models were used to evaluate the association of HDL-C and TC/HDL ratio with coronary plaque volumes. RESULTS: Of the 190 subjects the average (SD) age was 58.9 (9.8) years, with 63% being male. After adjustment for cardiovascular risk factors, HDL- C (>40 mg/dl) is inversely associated with fibrous (p = 0.003), fibrous fatty (p = 0.007), low attenuation plaque (LAP) (p = 0.007), total non-calcified plaque (TNCP) (p = 0.002) and total plaque (TP)(p = 0.004) volume. Furthermore, the TC/HDL ratio (> 4.0) is associated with fibrous (p = 0.047) and total non-calcified plaque (p = 0.039), but not with fibrofatty, LAP, dense calcified plaque, or TP volume. CONCLUSION: There is a strong association between low HDL-C levels and increasing TC/HDL ratio with certain types of coronary plaque characteristics, independent of traditional risk factors. The findings of this study suggest mechanistic evidence supporting the protective role of HDL-C and the TC/HDL ratio's clinical relevance in coronary artery disease management.

Radiation Doses in Patients Undergoing Computed Tomographic Coronary Artery Calcium Evaluation With a 64-Slice Scanner Versus a 256-Slice Scanner.

Computed tomographic coronary artery calcium scanning enables cardiovascular risk stratification; however, exposing patients to high radiation levels is an ongoing concern. New-generation computed tomographic systems use lower radiation doses than older systems do. To quantify comparative doses of radiation exposure, we prospectively acquired images from 220 patients with use of a 64-slice GE LightSpeed VCT scanner (control group, n=110) and a 256-slice GE Revolution scanner (study group, n=110). The groups were matched for age, sex, and body mass index; statistical analysis included t tests and linear regression. The mean dose-length product was 21% lower in the study group than in the control group (60.2 ± 27 vs 75.9 ± 22.6 mGy·cm; P <0.001) and also in each body mass index subgroup. Similarly, the mean effective radiation dose was 21% lower in the study group (0.84 ± 0.38 vs 1.06 ± 0.32 mSv) and lower in each weight subgroup. After adjustment for sex, women in the study group had a lower dose-length product (50.4 ± 23.4 vs 64.7 ± 27.6 mGy·cm) than men did and received a lower effective dose (0.7 ± 0.32 vs 0.9 ± 0.38 mSv) (P=0.009). As body mass index and waist circumference increased, so did doses for both scanners. Our study group was exposed to radiation doses lower than the previously determined standard of 1 mSv, even after adjustment for body mass index and waist circumference. In 256-slice scanning for coronary artery calcium, radiation doses are now similar to those in lung cancer screening and mammography.

Relationship between genomic risk scores (GRS) and coronary artery calcium (CAC) score: A pilot study.

BACKGROUND: Coronary artery disease (CAD) genomic risk scores (GRS), as FDR202, GRS46K, 1.7M, and MetaGRS, help in assessing cardiovascular related morbidity and mortality. Interventions to adhere to a healthy lifestyle as a means of prevention based on the GRS have a potential to greatly reduce incident CAD event rates. We performed a prospective observational study to see the relationship between GRS and coronary artery calcium (CAC) scoring in individuals who are at risk. METHODS: 104 subjects with mean age 55.1 ± 8.8 years were enrolled and consented and all the participants underwent CAC scoring. 55 (53%) were male. CAC score was measured using the Agatston method. Spearman correlation analysis assessed relationships between GRS scores and CAC scores, in the entire sample and in subjects with CAC score greater than zero. Multivariable linear regression analyzed associations while adjusting potential confounding variables. RESULTS: Mean ± SD CAC score of the study population was 49.0 ± 130. A significant negative correlation was noted between FDR202 Prevalence and total CAC Score in 39 subjects with CAC >0, r = -0.35, p = 0.02. Multivariable analysis shows a significant association between FDR202 prevalence and log adjusted CAC score in subjects with CAC >0 while adjusting age, gender, hypertension and hyperlipidemia (ß = -0.2, SE = 0.1, p = 0.04). No significant correlations were found between GRS46K, 1.7M, and MetaGRS with CAC score. CONCLUSION: Additional research is necessary in a larger population to evaluate the potential role of GRS for the detection of CAD. This allows the individuals to adopt a healthy lifestyle modification to minimize the cardiovascular risk and delays the onset of most diseases of old age to prolong the life.

Elevated serum thyrotropin levels and endothelial dysfunction in a prospective hemodialysis cohort.

INTRODUCTION: Thyroid dysfunction is a highly prevalent yet under-recognized complication in hemodialysis patients. In the general population, hypothyroidism has been associated with endothelial dysfunction due to impaired vasodilator synthesis and activity. Little is known about the association of serum thyrotropin (TSH), the most sensitive and specific single biochemical metric of thyroid function, with endothelial function in hemodialysis patients. METHODS: In a secondary analysis of 99 patients from the Anti-inflammatory and anti-oxidative nutrition in hypoalbuminemic dialysis patients (AIONID) trial, we examined measurements of serum TSH and endothelial function ascertained by fingertip digital thermal monitoring (DTM), a novel method used to measure micro-vascular reactivity, collected within a 90-day period. DTM was used to measure changes in fingertip temperature during and after an ischemic stimulus (blood pressure cuff occlusion) as an indicator of changes in blood flow, and two DTM indices were assessed, namely adjusted (a) Temperature Rebound (TR), defined as the maximum temperature rebound post-cuff deflation, and adjusted (b) Area Under the Temperature Curve (TMP-AUC), defined as area under the curve between the maximum and minimum temperatures. We examined the relationship between serum TSH with impaired TR (separately) and TMP-AUC (both defined as less than the median level of observed values) using multivariable logistic regression. FINDINGS: In unadjusted and case-mix analyses, higher serum TSH levels (defined as the three highest quartiles) were associated with lower (worse) TR (ref: lowest TSH quartile): ORs (95% CI) 2.64 (1.01-6.88) and 2.85 (1.08-7.57), respectively. In unadjusted and case-mix analyses, higher TSH levels were associated with lower (worse) TMP-AUC: ORs (95% CI) 2.64 (1.01-6.88) and 2.79 (1.06-7.38), respectively. DISCUSSION: In HD patients, higher serum TSH levels were associated with worse micro-vascular reactivity measured by DTM. Further studies are needed to determine if thyroid hormone supplementation improves endothelial function in hemodialysis patients with lower levels of thyroid function.

The relationship between coronary artery calcium density and optical coherence tomography-derived plaque characteristics.

BACKGROUND AND AIMS: Although coronary artery calcium (CAC) density has been associated with plaque stability, pathological evidence is lacking. We investigated the relationship between coronary computed tomography (CCT)-derived CAC density and multiple calcified and high-risk plaque (HRP) characteristics using optical coherence tomography (OCT). METHODS: We analyzed 83 plaques from 33 stable angina patients who underwent both CCT and OCT. CAC density was measured at calcium plaques with ≥90 Hounsfield units (HU) and ≥130 HU using custom CT software. The correlation between median CAC density and OCT-derived calcium size (thickness and area) was assessed. To investigate whether median CAC densities measured at the 90 HU threshold were associated with plaque vulnerability, OCT-derived plaque characteristics and HRP characteristics were compared between the low (90-129 HU), intermediate (130-199 HU) and high (≥200 HU) CAC HU groups. RESULTS: Median CAC densities at 130 HU were moderately associated with calcium thickness (R = 0.573, p < 0.001) and area (R = 0.560, p < 0.001). Similar results were observed at 90 HU (thickness, R = 0.615, p < 0.001; area, R = 0.612, p < 0.001). Among groups with low, intermediate and high HU levels, calcium thickness (0.42 ± 0.14 mm, 0.60 ± 0.17 mm and 0.77 ± 0.19 mm, respectively; p < 0.001) and area (0.55 ± 0.29 mm2, 1.20 ± 0.58 mm2 and 1.78 ± 0.87 mm2, respectively; p < 0.001) were significantly greater in the high HU group. HRP characteristics, however, did not differ among the three groups. CONCLUSIONS: OCT-derived calcium size, but not HRP characteristics, were associated with CAC density, suggesting that CAC density is driven mainly by calcified plaque size but not local plaque vulnerability.

Lower Radiation Dosing in Cardiac CT Angiography: The CONVERGE Registry.

Coronary artery disease is the leading cause of morbidity and mortality. Tools have been developed to accurately diagnose and evaluate coronary artery disease. Coronary CT angiography (CCTA) provides detailed imaging to deliver precise analysis and prognostic information. We sought to compare the radiation dose from a 256-detector-row CT scanner with that from a 64-detector-row CT scanner across a similar profile of patients. Methods: Consecutive patients were screened for the Converge Registry study and, after consenting to be included, were enrolled in accordance with an Institutional Review Board-approved protocol. A control group who underwent 64-row CCTA were matched by age, sex, and body mass index (BMI) with a group who underwent 256-row CCTA. Results: We compared 110 patients in each group. We found that mean dose-length product (DLP) was significantly lower in the 256-row group than in the 64-row group (P < 0.05). The radiation dose was reduced by 32% with use of the 256-row scanner for BMIs of 18.5-24.9 (DLP, 111.2 vs. 76.1 mGy-cm [1.56 vs. 1.07 mSv]; P < 0.05). For each BMI subgroup, there was a significant decrease in dose. Regression analysis found that with increasing BMIs, DLP significantly increased for both scanners. Conclusion: The 256-row scanner provided CCTA scans at significantly lower radiation doses than the 64-row scanner in different BMI groups, with all other variables accounted for. Lower radiation exposure along with lower contrast requirements can provide images with high diagnostic accuracy and less risk to the patient.

Relationship between cardio-ankle vascular index and obstructive coronary artery disease.

BACKGROUND: Cardio-ankle vascular index (CAVI) is an inexpensive, noninvasive, office-based method to evaluate arterial stiffness in the aorta and legs, which reflects the degree of coronary atherosclerosis. It has been applied clinically to assess arterial stiffness in patients who were diagnosed with coronary artery disease (CAD), stroke and those at risk. We intend to evaluate relationship between the CAVI and obstructive CAD. METHODS: We enrolled 285 individuals with mean age of 55.8 ± 13.5 years, clinically referred for Coronary Artery Calcium (CAC) scoring and coronary computed tomography angiography (CCTA) at our site. After informed consent, CAVI measurements were done using a vascular screening system, VaSera VS-1500 AU (FUKUDA Denshi) on the same day of CCTA. CAC was measured using the Agatston method. A semiquantitative scale was used by CCTA readers to grade the extent of luminal stenosis as a percentage of the vessel diameter using visual estimations. We evaluated if CAVI was associated with severe stenosis (>50%) or CAC >100, defined as obstructive CAD. RESULTS: The degree of CAC and severe coronary stenosis demonstrated significant correlation with CAVI (r = 0.44, P ≤ 0.0001 and r = 0.43, P ≤ 0.0001). Receiver operating characteristic curve analysis indicated that CAVI measure of 7.8 was an optimal cut-point for sensitivity and specificity in detecting obstructive CAD. Unadjusted logistic regression demonstrated CAVI >7.8, significantly associated with obstructive CAD [odds ratio (OR) = 4.60, 95% confidence interval (CI) (2.0-10.56), P = 0.0003] and CAC score >100 [OR = 6.96, 95% CI (3.68-13.17), P < 0.0001]. CONCLUSION: CAVI reflects coronary atherosclerosis and may be used as a screening tool for early identification of subclinical atherosclerosis in preventive care and optimize management.

Non-contrast cardiac CT-based quantitative evaluation of epicardial and intra-thoracic fat in healthy, recently menopausal women: Reproducibility data from the Kronos Early Estrogen Prevention Study.

BACKGROUND: Cardiac fat is emerging as an important parameter for cardiovascular risk stratification. Accurate and reproducible volumetric measurements can facilitate in the serial assessment of cardiac fat by computed tomography (CT). We assessed the intra- and inter-observer variability of cardiac fat volumetric measurements using a semi-automated CT software. METHODS: We used non-contrast coronary calcium CT scans to quantify epicardial and intra-thoracic fat volumes. Two expert readers analyzed baseline and follow up CT scans of 45 subjects by using a semi-automated CT software (QFAT 2.0, Cedars Sinai-Medical Center). Correlation and Bland-Altman analysis was performed for both intra- and inter-observer comparisons for each cardiac fat type. RESULTS: The intra-observer correlation coefficients ranged between 0.86 to 0.99 and 0.87 to 0.99 for epicardial (median fat per reader (cm3) 20.9 to 25.7) and intra-thoracic (median fat per reader (cm3) 27.1 to 31.6) fat volumes respectively, with no significant differences between individual data points (all p > 0.38). The inter-observer correlation coefficient was 0.99 (p < 0.0001 for correlation) for both epicardial and intra-thoracic fat. By Bland-Altman analysis for epicardial fat measurements, mean difference of intra-observer was 0.90 cm3 with 95% confidence intervals (0.22,1.7) and -1.8 cm3 for inter-observer, with 95% CI (-2.9, -0.69). Bland-Altman plots for intra-thoracic fat measurements were similarly impressive for both inter- and intra-observer reads. CONCLUSIONS: Our data showed that measuring epicardial and intra-thoracic fat volumes by CT using a semi-automated software has excellent intra-observer and inter-observer reliability. Cardiac fat volumes can be obtained easily and reproducibly from routine calcium scoring scans and may help in assessing cardiovascular risk. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00154180; Keywords: Epicardial fat volume; intra-thoracic fat volume; computed tomography; intra-observer; inter-observer.

Association of high-density lipoprotein levels with baseline coronary plaque volumes by coronary CTA in the EVAPORATE trial.

BACKGROUND AND AIMS: Dyslipidemia with elevated triglycerides (TGL) and low high-density lipoprotein cholesterol (HDL-C) predicts residual cardiovascular risk, despite goal LDL-C levels and optimal statin therapy. Coronary plaque characterization by CCTA can provide mechanistic understanding of coronary artery disease and associated prognosis. The role of HDL-C in the pathogenesis of atherosclerosis is not well understood in statin-treated patients with elevated TGL. We sought to examine the association of HDL-C levels with baseline coronary plaque volumes, namely total plaque (TP) and total non-calcified plaque (TNCP) volumes by CCTA in participants enrolled in the EVAPORATE trial. METHODS: We analyzed 80 participants who were enrolled in the trial. Linear regression analysis as a univariate and multivariate model adjusted for significant cardiovascular risk factors was performed to evaluate independent association of HDL-C and baseline coronary plaque volumes. In an exploratory analysis, stratified by sex, we compared the association of serum HDL-C levels with baseline coronary plaque volumes in males and females. RESULTS: Mean (SD) age of participants (n = 80) was 57.1 (8.6) years and 43% were male. Median (Inter Quartile Range/IQR) log-TNCP volume was 83.0 (0.1-7.3) mm3 and median (IQR) log-TP volume was 144.8 (0.1-7.1) mm3. After adjustment for relevant clinical covariates including age, gender, BMI, hypertension, diabetes, past smoking and baseline TGL levels, increasing levels of HDL-C remain independently associated with lower baseline log-TNCP volumes (ß: 0.043 ± 0.021, p = 0.042) and baseline log-TP volumes (ß: 0.046 ± 0.022, p = 0.035) on CCTA. On stratifying by sex in a multivariable regression analysis, HDL-C levels were inversely associated with baseline log-TNCP volumes (ß: 0.066 ± 0.026, p = 0.018) and log-TP volumes (ß: 0.077 ± 0.025, p = 0.004) in females, but not in males (log-TNCP volumes ß: 0.038 ± 0.034, p = 0.282) and log-TP volumes (ß: -0.033 ± 0.036, p = 0.364). CONCLUSIONS: In a cohort of statin treated patients with known atherosclerosis and residually elevated TGL, there was a significant inverse relationship between HDL-C levels and baseline coronary plaque, TP and TNCP volumes on CCTA. Our findings provide more detailed mechanistic evidence regarding the protective role of HDL-C in coronary atherosclerosis in a high-risk cohort. Further investigation to evaluate the interaction of HDL-C levels and coronary plaque volumes on differential CVD risk in statin-treated patients with elevated TGL levels is warranted.

A novel density-volume calcium score by non-contrast CT predicts coronary plaque burden on coronary CT angiography: Results from the MACS (Multicenter AIDS cohort study).

BACKGROUND: The purpose of this study is to determine if a new score calculated with coronary artery calcium (CAC) density and volume is associated with total coronary artery plaque burden and composition on coronary CT angiography (CCTA) compared to the Agatston score (AS). METHODS: We identified 347 men enrolled in the Multicenter AIDS cohort study who underwent contrast and non-contrast CCTs, and had CAC>0. CAC densities (mean Hounsfield Units [HU]) per plaque) and volumes on non-contrast CCT were measured. A Density-Volume Calcium score was calculated by multiplying the plaque volume by a factor based on the mean HU of the plaque (4, 3, 2 and 1 for 130-199, 200-299, 300-399, and ≥400HU). Total Density-Volume Calcium score was determined by the sum of these individual scores. The semi-quantitative partially calcified and total plaque scores (PCPS and TPS) on CCTA were calculated. The associations between Density-Volume Calcium score, PCPS and TPS were examined. RESULTS: Overall, 2879 CAC plaques were assessed. Multivariable linear regression models demonstrated a stronger association between the log Density-Volume Calcium score and both the PCPS (ß 0.99, 95%CI 0.80-1.19) and TPS (ß 2.15, 95%CI 1.88-2.42) compared to the log of AS (PCPS: ß 0.77, 95%CI 0.61-0.94; TPS: ß 1.70, 95%CI 1.48-1.94). Similar results were observed for numbers of PC or TP segments. CONCLUSION: The new CAC score weighted towards lower density demonstrated improved correlation with semi-quantitative PC and TP burden on CCTA compared to the traditional AS, which suggests it has utility as an alternative measure of atherosclerotic burden.

Lower Radiation Dosing in Cardiac Computed Tomographic Angiography: the CONVERGE Registry.

Intro: Coronary artery disease is the leading cause for morbidity and mortality. Tools have been developed to accurately diagnose and evaluate coronary artery disease. Coronary computed tomographic angiography (CCTA) scans provide detailed imaging along with analysis to in order to deliver precise analysis and prognostic information. We sought to evaluate the radiation doses of the 256 detector CT scanner to a 64 slice scanner across a similar profile of patients. Methods: Consecutive patients were screened, enrolled, and consented for the Converge Registry study, in accordance with the Institutional Review Board (IRB) approved protocol. 110 patients underwent CCTA using the GE Revolution 256 detector CT scanner. We matched patients by age, gender and body mass index (BMI) who underwent 64 slice CT scanning. Results: We compared 110 patients in each group. We found that mean dose length product (DLP, presented also in the tables below in millisieverts (mSv)) was significantly lower in the Revolution 256 detector group compared to the 64 slice control group (p<0.05). The radiation dose was reduced 32% with use of Revolution 256 detector scanner for BMI between 18.5 and 24.9 (DLP = 111.2 vs 76.1; 1.56 vs 1.07 mSv; p<0.05). For each BMI subgroup, there was a significant decrease in dose. Regression analysis found that with the increase in BMI both scanners experienced a significant increase in DLP. Conclusion: We are able to demonstrate that the 256 slice CT scanner is able to provide CCTA scans at significantly lower radiation doses compared to the 64 row scanner at different BMI groups, with all other variables accounted for. Lower radiation exposures along with lower contrast requirements can provide quality imaging with high diagnostic accuracy and less risk to the patient.

Changes in Coronary Plaque Volume: Comparison of Serial Measurements on Intravascular Ultrasound and Coronary Computed Tomographic Angiography.

Serial measurements of coronary plaque volume have been used to evaluate drug efficacy in atherosclerotic progression. However, the usefulness of computed tomography for this purpose is unknown. We investigated whether the change in total plaque volume on coronary computed tomographic angiography is associated with the change in segment plaque volume on intravascular ultrasound. We prospectively enrolled 11 consecutive patients (mean age, 56.3 ± 5 yr; 6 men) who were to undergo serial invasive coronary angiographic examinations with use of grayscale intravascular ultrasound and coronary computed tomography, performed <180 days apart at baseline and from 1 to 2 years later. Subjects underwent 186 serial measurements of total plaque volume on coronary computed tomography and 22 of segmental plaque volume on intravascular ultrasound. We used semiautomated software to examine percentage relationships and changes between total plaque and segmental plaque volumes. No significant correlations were found between percentages of total coronary and segment coronary plaque volume, nor between normalized coronary plaque volume. However, in the per-patient analysis, there were strong correlations between the imaging methods for changes in total coronary and segment coronary plaque volume (r=0.62; P=0.04), as well as normalized plaque volume (r=0.82; P=0.002). Per-patient change in plaque volume on coronary computed tomography is significantly associated with that on intravascular ultrasound. Computed tomographic angiography may be safer and more widely available than intravascular ultrasound for evaluating atherosclerotic progression in coronary arteries. Larger studies are warranted.

Multicenter AIDS Cohort Study Quantitative Coronary Plaque Progression Study: rationale and design.

BACKGROUND AND AIM: The association of HIV with coronary atherosclerosis has been established; however, the progression of coronary atherosclerosis over time among participants with HIV is not well known. The Multicenter AIDS Cohort Study Quantitative Coronary Plaque Progression Study is a large prospective multicenter study quantifying progression of coronary plaque assessed by serial coronary computed tomography angiography (CTA). PATIENTS AND METHODS: HIV-infected and uninfected men who were enrolled in the Multicenter AIDS Cohort Study Cardiovascular Substudy were eligible to complete a follow-up contrast coronary CTA 3-6 years after baseline. We measured coronary plaque volume and characteristics (calcified and noncalcified plaque including fibrous, fibrous-fatty, and low attenuation) and vulnerable plaque among HIV-infected and uninfected men using semiautomated plaque software to investigate the progression of coronary atherosclerosis over time. CONCLUSION: We describe a novel, large prospective multicenter study investigating incidence, transition of characteristics, and progression in coronary atherosclerosis quantitatively assessed by serial coronary CTAs among HIV-infected and uninfected men.

The relationship between cardio-ankle vascular index and subclinical atherosclerosis evaluated by cardiac computed tomographic angiography.

BACKGROUND: The cardio-ankle vascular index (CAVI) is a new noninvasive index to evaluate arterial stiffness. We investigated whether CAVI can predict severity, extent, and burden of coronary artery disease by comparing results with cardiac computed tomographic angiography (CCTA). HYPOTHESIS: CAVI may predict the presence of subclinical atherosclerosis. METHODS: We prospectively enrolled 95 patients (66% male; mean age, 50 ± 16 years) who underwent both CCTA and CAVI consecutively. We evaluated if CAVI correlated with (1) severe stenosis (≥50%); (2) plaque extent, determined by a segment-involvement score (SIS), defined by the total number of coronary artery segments containing any plaque; and (3) plaque burden, determined by a segment-stenosis score (SSS), defined by the extent of obstruction of coronary luminal diameter in individual coronary artery segments. RESULTS: Bivariate analysis showed a statistically significant relationship not only between CAVI and SIS, but also between CAVI and SSS (r2 = 0.4, P < 0.0001 for SIS; r2 = 0.36, P < 0.0001 for SSS). Multivariable logistic analysis demonstrated that CAVI is significantly associated with SSS >5 (odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.1-7.8, P = 0.03) and SIS >5 (OR: 2.3, 95% CI: 1.1-5.8, P = 0.02), but not severe stenosis (OR: 1.7, 95% CI: 0.9-4.3, P = 0.13), after adjusting for age, sex, chest pain, hypertension, dyslipidemia, family history, diabetes, and current smoking. CONCLUSIONS: We demonstrated that CAVI had a significant relationship with subclinical coronary atherosclerosis evaluated by CCTA, especially in relation to plaque burden and plaque extent, but not severe stenosis. Thus, CAVI may reflect coronary atherosclerosis burden more than severity.