The utility of coronary artery calcium scoring to enhance cardiovascular risk assessment for South Asian adults.

South Asian individuals represent a highly diverse population and are one of the fastest growing ethnic groups in the United States. This population has a high prevalence of traditional and non-traditional cardiovascular disease (CVD) risk factors and a disproportionately high prevalence of coronary heart disease. To reflect this, current national society guidelines have designated South Asian ancestry as a "risk enhancing factor" which may be used to guide initiation or intensification of statin therapy. However, current methods of assessing cardiovascular risk in South Asian adults may not adequately capture the true risk in this diverse population. Coronary artery calcium (CAC) scoring provides a reliable, reproducible, and highly personalized method to provide CVD risk assessment and inform subsequent pharmacotherapy recommendations, if indicated. This review describes the utility of CAC scoring for South Asian individuals.

Assessment of Coronary Artery Calcium Scoring to Guide Statin Therapy Allocation According to Risk-Enhancing Factors: The Multi-Ethnic Study of Atherosclerosis.

Importance: The 2018 American Heart Association/American College of Cardiology Guideline on the Management of Blood Cholesterol recommends the use of risk-enhancing factor assessment and the selective use of coronary artery calcium (CAC) scoring to guide the allocation of statin therapy among individuals with an intermediate risk of atherosclerotic cardiovascular disease (ASCVD). Objective: To examine the association between risk-enhancing factors and incident ASCVD by CAC burden among those at intermediate risk of ASCVD. Design, Setting, and Participants: The Multi-Ethnic Study of Atherosclerosis is a multicenter population-based prospective cross-sectional study conducted in the US. Baseline data for the present study were collected between July 15, 2000, and July 14, 2002, and follow-up for incident ASCVD events was ascertained through August 20, 2015. Participants were aged 45 to 75 years with no clinical ASCVD or diabetes at baseline, were at intermediate risk of ASCVD (≥7.5% to <20.0%), and had a low-density lipoprotein cholesterol level of 70 to 189 mg/dL. Exposures: Family history of premature ASCVD, premature menopause, metabolic syndrome, chronic kidney disease, lipid and inflammatory biomarkers, and low ankle-brachial index. Main Outcomes and Measures: Incident ASCVD over a median follow-up of 12.0 years. Results: A total of 1688 participants (mean [SD] age, 65 [6] years; 976 men [57.8%]). Of those, 648 individuals (38.4%) were White, 562 (33.3%) were Black, 305 (18.1%) were Hispanic, and 173 (10.2%) were Chinese American. A total of 722 participants (42.8%) had a CAC score of 0. Among those with 1 to 2 risk-enhancing factors vs those with 3 or more risk-enhancing factors, the prevalence of a CAC score of 0 was 45.7% vs 40.3%, respectively. Over a median follow-up of 12.0 years (interquartile range [IQR], 11.5-12.6 years), the unadjusted incidence rate of ASCVD among those with a CAC score of 0 was less than 7.5 events per 1000 person-years for all individual risk-enhancing factors (with the exception of ankle-brachial index, for which the incidence rate was 10.4 events per 1000 person-years [95% CI, 1.5-73.5]) and combinations of risk-enhancing factors, including participants with 3 or more risk-enhancing factors. Although the individual and composite addition of risk-enhancing factors to the traditional risk factors was associated with improvement in the area under the receiver operating curve, the use of CAC scoring was associated with the greatest improvement in the C statistic (0.633 vs 0.678) for ASCVD events. For incident ASCVD, the net reclassification improvement for CAC was 0.067. Conclusions and Relevance: In this cross-sectional study, among participants with CAC scores of 0, the presence of risk-enhancing factors was generally not associated with an overall ASCVD risk that was higher than the recommended treatment threshold for the initiation of statin therapy. The use of CAC scoring was associated with significant improvements in the reclassification and discrimination of incident ASCVD. The results of this study support the utility of CAC scoring as an adjunct to risk-enhancing factor assessment to more accurately classify individuals with an intermediate risk of ASCVD who might benefit from statin therapy.

Coronary Artery Calcium Progression Among the US and Japanese Men.

Background The risk of coronary heart disease remains low in Japan, although distributions of several coronary risk factors have become comparable with those in the United States. We prospectively compared coronary atherosclerosis burden, measured with coronary artery calcium (CAC) progression, between men in the 2 countries. Methods In 2 population-based samples of 1712 US White, Black, Hispanic, Chinese men (baseline, 2000-2002) and 697 Japanese men in Japan (2006-2008) aged 45-74 years without clinical cardiovascular disease, we quantified CAC progression by serial computed tomography with medians of 3.4 and 5.2 years between scans, respectively. Results Among White, Black, Hispanic, Chinese, and Japanese men free of baseline CAC, CAC incidence was observed in 35.2%, 26.9%, 29.2%, 18.9%, and 29.2%, respectively. After adjustment for times between scans, demographics, behaviors, coronary risk factors, and their changes between scans, White men had significantly higher CAC incidence than Japanese men (relative risk, 1.68; 95% CI, 1.13-2.50). Among those with detectable baseline CAC, after similar adjustments, all the US race/ethnic groups had significantly greater annual changes in CAC score (mean [95% CI]: 39.4 [35.2-43.6] for White, 26.9 [21.4-32.4] for Black, 30.6 [24.7-36.5] for Hispanic, and 30.2 [22.6-37.8] for Chinese men) than Japanese men (15.9 [10.1-21.8]). Conclusions We found a higher CAC incidence among US White men and greater increases in existing CAC among all the US race/ethnic groups than among Japanese men in Japan. These differences persisted despite adjustment for differences in coronary risk factors.

Use of coronary artery calcium testing to improve coronary heart disease risk assessment in a lung cancer screening population: The Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND: Assessment of coronary artery calcium (CAC) during lung cancer screening chest computed tomography (CT) represents an opportunity to identify asymptomatic individuals at increased coronary heart disease (CHD) risk. We determined the improvement in CHD risk prediction associated with the addition of CAC testing in a population recommended for lung cancer screening. METHODS: We included 484 out of 6814 Multi-Ethnic Study of Atherosclerosis (MESA) participants without baseline cardiovascular disease who met U.S. Preventive Service Task Force CT lung cancer screening criteria and underwent gated CAC testing. 10 year-predicted CHD risks with and without CAC were calculated using a validated MESA-based risk model and categorized into low (<5%), intermediate (5%-10%), and high (≥10%). The net reclassification improvement (NRI) and change in Harrell's C-statistic by adding CAC to the risk model were subsequently determined. RESULTS: Of 484 included participants (mean age = 65; 39% women; 32% black), 72 (15%) experienced CHD events over the course of follow-up (median = 12.5 years). Adding CAC to the MESA CHD risk model resulted in 17% more participants classified into the highest or lowest risk categories and a NRI of 0.26 (p = 0.001). The C-statistic improved from 0.538 to 0.611 (p = 0.01). CONCLUSIONS: CHD event rates were high in this lung cancer screening eligible population. These individuals represent a high-risk population who merit consideration for CHD prevention measures regardless of CAC score. Although overall discrimination remained poor with inclusion of CAC scores, determining whether those reclassified to an even higher risk would benefit from more aggressive preventive measures may be important.

Race/ethnic and sex disparities in the non-alcoholic fatty liver disease-abdominal aortic calcification association: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND AIMS: This study investigated the associations of non-alcoholic fatty liver disease (NAFLD) and abdominal aortic calcification (AAC) volume and density, and whether these relationships vary by race/ethnicity and/or sex, information that are limited in current literature. METHODS: We studied 1004 adults from the Multi-Ethnic Study of Atherosclerosis to assess the relationship between NAFLD (liver-to-spleen ratio <1) and the following measures of AAC: presence (volume score >0, using Poisson regression); change in volume score (increasing vs. no change, using Poisson regression); and morphology (volume and density score, where volume score >0, using linear regression); and interaction by race/ethnicity and sex. RESULTS: Among Blacks, those with NAFLD had greater prevalence for AAC compared to Whites regardless of sex (Prevalence Ratio [PR] = 1.41, CI = 1.15-1.74, p-interaction = 0.02). Concurrent interaction by race/ethnicity and sex was found comparing Chinese and Blacks to Whites (p-interaction = 0.017 and 0.042, respectively) in the association between NAFLD and the prevalence of increasing AAC. Among women, this relationship was inverse among Chinese (PR = 0.59, CI = 0.28-1.27), and positive among Whites (PR = 1.34, CI = 1.02-1.76). This finding was reversed evaluating the men counterpart. Black men also had a positive association (PR = 1.86, CI = 1.29-2.70), which differed from the inverse relationship among White men, and was greater compared to Black women (PR = 1.45, CI = 1.09-1.94). NAFLD was unrelated to AAC morphology. CONCLUSIONS: NAFLD was related to the presence of AAC, however, limited to Blacks. Significant concurrent interaction by race/ethnicity (Chinese and Blacks vs. Whites) and sex was found in the relationship between NAFLD and increasing AAC. These findings suggest disparities in the pathophysiologic pathways in which atherosclerosis develops.

Inflammatory Obesity Phenotypes, Gender Effects, and Subclinical Atherosclerosis in African Americans: The Jackson Heart Study.

OBJECTIVE: Reasons for variations in atherosclerotic burden among individuals with similar levels of obesity are poorly understood, especially in African Americans. This study examines whether high-sensitivity C-reactive protein (hsCRP) is useful for discriminating between benign and high-risk obesity phenotypes for subclinical atherosclerosis in African Americans. APPROACH AND RESULTS: Participants from the Jackson Heart Study (n=4682) were stratified into 4 phenotypes based on the presence of National Heart and Lung and Blood Institute definition of obesity or obesity-equivalent (body mass index ≥30 or body mass index 25-30 with waist circumference >102 cm in men and >88 cm in women) and inflammation by hsCRP ≥2 mg/L. Using multivariate regression models, we conducted cross-sectional analyses of the association between inflammatory obesity phenotypes and subclinical atherosclerosis determined by carotid intima-media thickness or coronary artery calcium scores. Sex-specific analyses were conducted given significant interaction for gender (P=0.03). The prevalence of obesity or equivalent was 65%, of which 30% did not have inflammation. Conversely, 37% of nonobese individuals had inflammation. Among nonobese men, hsCRP ≥2 mg/L identified a subset of individuals with higher carotid intima-media thickness (adjusted mean difference =0.05, 95% confidence interval 0.02, 0.08 mm) compared with their noninflammatory counterparts. Among obese men, hsCRP <2 mg/L identified a subset of individuals with lower coronary artery calcium compared with their inflammatory counterparts. Among women, associations between hsCRP and carotid intima-media thickness or coronary artery calcium were not found. CONCLUSIONS: In the largest African American population-based cohort to date, hsCRP was useful in identifying a subset of nonobese men with higher carotid intima-media thickness, but not in women. hsCRP did not identify a subset of obese individuals with less subclinical atherosclerosis.

Associations of cardiovascular disease risk factors with abdominal aortic calcium volume and density: The Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND AND AIMS: Abdominal aortic calcium (AAC) predicts future cardiovascular disease (CVD) events and all-cause mortality independent of CVD risk factors. The standard AAC score, the Agatston, up-weights for greater calcium density, and thus models higher calcium density as associated with increased CVD risk. We determined associations of CVD risk factors with AAC volume and density (separately). METHODS: In a multi-ethnic cohort of community living adults, we used abdominal computed tomography scans to measure AAC volume and density. Multivariable linear regression was used to determine the period cross-sectional independent associations of CVD risk factors with AAC volume and AAC density in participants with prevalent AAC. RESULTS: Among 1413 participants with non-zero AAC scores, the mean age was 65 ± 9 years, 52% were men, 44% were European-, 24% were Hispanic-, 18% were African-, and 14% were Chinese Americans (EA, HA, AA, and CA respectively). Median (interquartile range, IQR) for AAC volume was 628 mm3 (157-1939 mm3), and mean AAC density was 3.0 ± 0.6. Compared to EA, each of HA, AA, and CA had lower natural log (ln) AAC volume, but higher AAC density. After adjustments for AAC density, older age, ever smoking history, higher systolic blood pressure, elevated total cholesterol, reduced HDL cholesterol, statin and anti-hypertensive medication use, family history of myocardial infarction, and alcohol consumption were significantly associated with higher ln(AAC volume). In contrast, after adjustments for ln(AAC volume), older age, ever smoking history, higher BMI, and lower HDL cholesterol were significantly associated with lower AAC density. CONCLUSIONS: Several CVD risk factors were associated with higher AAC volume, but lower AAC density. Future studies should investigate the impact of calcium density of aortic plaques in CVD.

Charting the Future for Ethnicity and Health Research: Clinical and Population Science Insights From the MESA.

The MESA (Multi-Ethnic Study of Atherosclerosis) has been highly successful in investigating the prevalence, characteristics, and progression of subclinical cardiovascular disease (CVD) in a multiethnic American cohort of adult men and women free of CVD at baseline. MESA has also championed the use of novel biomarkers and emerging imaging techniques for the assessment of subclinical CVD and has created an extensive set of data that continues to fuel dozens of ongoing analyses. Insights from MESA include the first demonstration of ethnic differences in coronary artery calcification and its association with subclinical disease progression and incident CVD. Other findings include ethnic differences in the prevalence of pharmacological, behavioral, and lifestyle interventions for the primary prevention of CVD. MESA has also shown the association between residential neighborhood characteristics and behavioral and biomedical risk factors for CVD. This vast amount of data documenting ethnic differences in progression of subclinical CVD, diabetes, kidney disease, and pulmonary disease contrasts sharply with the relative scarcity of specific information that can pave the way for the elimination of racial and ethnic disparities. Intervention research, however, goes beyond the original objectives of MESA and other observational studies. The time has now come to build on the legacy of MESA by supporting rigorous intervention research that informs clinical and public health strategies as well as policy and environmental changes for eliminating racial and ethnic disparities in CVD and other chronic diseases and advancing the health of multiethnic communities.

Low-dose CT coronary angiography for assessment of coronary artery disease in patients with type 2 diabetes--a cross-sectional study.

BACKGROUND: Silent coronary artery disease (CAD) is prevalent in type 2 diabetes mellitus (T2DM). Although coronary computed tomography angiography (CCTA) over recent years has emerged a useful tool for assessing and diagnosing CAD it's role and applicability for patients with T2DM is still unclarified, in particular in asymptomatic patients. We aimed to assess the role of CCTA in detecting and characterizing CAD in patients with T2DM without cardiac symptoms when compared to gold standard invasive coronary angiography (ICA). METHODS: This was a cross-sectional analysis of patients with T2DM without symptomatic CAD enrolled in the Asker and Baerum Cardiovascular Diabetes Study who, following clinical examination and laboratory assessment, underwent subsequently CCTA and ICA. RESULTS: In total 48 Caucasian patients with T2DM (36 men, age 64.0 ± 7.3 years, diabetes duration 14.6 ± 6.4 years, HbA1c 7.4 ± 1.1 %, BMI 29.6 ± 4.3 kg/m(2)) consented to, and underwent, both procedures (CCTA and ICA). The population was at intermediate cardiovascular risk (mean coronary artery calcium score 269, 75 % treated with antihypertensive therapy). ICA identified a prevalence of silent CAD at 17 % whereas CCTA 35 %. CCTA had a high sensitivity (100 %) and a high negative predictive value (100 %) for detection of patients with CAD when compared to ICA, but the positive predictive value was low (47 %). CONCLUSIONS: Low-dose CCTA is a reliable method for detection and exclusion of significant CAD in T2DM and thus may be a useful tool for the clinicians. However, a low positive predictive value may limit its usefulness as a screening tool for all CAD asymptomatic patients with T2DM. Further studies should assess the applicability for risk assessment beyond the evaluation of the vascular bed.

Shared and discrepant susceptibility for carotid artery and aortic arch calcification: A genetic association study.

Genome-wide association studies (GWASs) have identified several risk loci for coronary artery calcification. Four single-nucleotide polymorphisms (SNPs, rs1537370, rs1333049, rs2026458 and rs9349379) were associated with coronary artery calcification with P values less than 5 × 10(-8) in GWASs. It is unclear if these associations exist in other vascular beds. Thus, we evaluated the impacts of these four SNPs on carotid artery and aortic arch calcification in this study. Computed tomography was applied to quantify the calcification of carotid artery and aortic arch. 860 patients with stroke completed calcification quantification and genotype testing were included in data analysis. Each SNP was evaluated for the association with carotid artery calcification, and with aortic arch calcification using generalized linear model. Among the four tested SNPs, rs2026458 was associated with calcification in both carotid artery (ß = 0.31, 95% confidence interval [CI] 0.10-0.52, P = 0.003) and aortic arch (ß = 0.32, 95% CI 0.10-0.54, P = 0.004), while rs1333049 was only associated with carotid artery calcification (ß = 0.28, 95% CI 0.06-0.50, P = 0.011). In gender-stratified analyses, rs2026458 had significant impacts on carotid artery (P = 0.003) and aortic arch calcification (P = 0.008) in male, but not in female patients; while rs1537370 was significantly associated with carotid artery calcification in female (P = 0.013), but not in male patients. In conclusion, SNPs associated with coronary artery calcification may also increase the risk of calcification in other arteries such as carotid artery and aortic arch.

Conventional versus image-based cardiovascular risk assessment in Korean adults.

OBJECTIVE: The aim of this study is to evaluate the difference between risk stratifications according to the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III) guideline and the coronary artery calcium score (CACS) in a Korean population at an intermediate risk. PARTICIPANTS AND METHODS: A total of 7988 nondiabetic individuals underwent coronary computed tomography to measure coronary artery calcium. The discordantly higher risk group (DHRG) was defined as individuals whose CACS risk category was discordantly higher than their risk category according to the NCEP-ATP III guideline. RESULTS: Among all individuals at a low to moderate risk according to NCEP-ATP III, 9.4% were reclassified to the DHRG by CACS. In the multivariate regression analysis, age [odds ratio, 95% confidence interval (CI): 1.140 (1.123-1.158)], female sex [0.312 (0.208-0.469)], alcohol consumption [1.383 (1.142-1.676)], uric acid [1.079 (1.005-1.158)], hemoglobin A1c [1.716 (1.225-2.404)], fasting insulin [1.275 (1.056-1.539)], and systolic blood pressure [1.008 (1.001-1.016)] were associated independently with the DHRG. In a receiver-operating characteristic analysis, age had the largest area under the curve (AUC) compared with all of the aforementioned significant variables [AUC (95% CI): 0.724 (0.705-0.743)] for the DHRG. For every 5 years over 35 years of age, the risk of being in the DHRG increases by 1.95. CONCLUSION: This study indicates that the NCEP-ATP III guideline underestimates cardiovascular risk in about 10% of asymptomatic nondiabetic Korean individuals in the lower to moderate risk group, and the discrepancy in risk stratification between NCEP-ATP III and CACS is particularly prominent in older individuals. This suggests that an image-based risk assessment such as a coronary calcium scan should be considered for more accurate risk stratification.

Coronary artery calcification and coronary atherosclerotic disease.

The presence of coronary artery calcium is closely associated with the presence of atherosclerotic lesions in the coronary vasculature. Detection of coronary calcium by imaging techniques has evolved over the last few decades and has become especially more sophisticated with advanced imaging technology. Whereas the status of coronary artery calcium as a marker of increased cardiovascular risk is well established, the indication for testing continues to be a topic of debate.