Reproducibility of coronary artery calcified plaque with cardiac 64-MDCT: the Multi-Ethnic Study of Atherosclerosis

Prognostic significance of aortic valve calcification in relation to coronary artery calcification for cardiovascular diseases

AIMS

Both coronary artery calcification (CAC) and aortic valve calcification (AVC) are strongly associated with cardiovascular diseases (CVDs), but data about the prognostic significance of multiple cardiovascular calcifications are limited. We aim to investigate the interaction relationship between AVC and CAC for major events.

METHODS AND RESULTS

We included 6695 participants from the Multi-Ethnic Study of Atherosclerosis at baseline and divided them into four groups: (i) no AVC or CAC; (ii) only AVC; (iii) only CAC; and (iv) with CAC and CAC. The Cox regression model and the Kaplan-Meier method were used to analyse CVD outcomes. We evaluated the interaction between AVC and CAC and their added predictive value based on the pooled cohort equations (PCEs). Subgroup analyses were also explored. Among 6695 participants (mean age 62.2 ± 10.2 years, 47.2% male), after follow-up, 943 cases (14.1%) of CVD and 1274 cases (19.0%) of all-cause death occurred. For participants with both AVC and CAC, the risk of CVD significantly increased [hazard ratio = 3.43 (2.69-4.37), P < 0.001], even higher than the sum of the ones with only AVC and only CAC. This trend remained the same for all-cause death and among subgroup analyses. The addictive interaction was statistically significant (P < 0.001). When AVC and CAC were added, the predictive value of PCEs increased.

CONCLUSION

Our results indicated a synergistic interaction between valve calcification and coronary calcification in CVDs. Management for both AVC and CAC may bring health co-benefits in preventing poor outcomes.

Coronary artery calcium scoring assessment in ultra-low-dose chest computed tomography

OBJECTIVES

To investigate the effect of non-electrocardiogram (ECG) -triggered ultra-low-dose CT (ULD-CT) with different reconstruction protocols on coronary artery calcium (CAC) scoring assessment, compared with ECG-triggered CAC CT (CAC-CT).

METHODS

This prospective study included 115 patients who underwent CAC-CT and ULD-CT scans under the same topogram images. CAC-CT adopted a prospective ECG-triggered sequential acquisition with a tube potential of 120 kV, and the reconstruction protocol was standard Qr36 + slice 3 mm (CACQr-3mm group). ULD-CT adopted a non-ECG-triggered high-pitch acquisition with a tube potential of Sn100 kV, and four groups of images (named ULDQr-3mm, ULDSa-3mm, ULDQr-1.5mm, and ULDSa-1.5mm) were reconstructed using different reconstruction algorithms (standard Qr36, kV-independent Sa36) and slice thicknesses (3 mm, 1.5 mm). The accuracy of CAC detection by ULD-CT was calculated. The agreement of the CAC score between ULD-CT and CAC-CT scans was assessed using intraclass correlation coefficients (ICC) and Bland-Altman plot, and the agreement of risk categorization was assessed using weighted kappa.

RESULTS

The sensitivity and specificity of the ULDSa-1.5mm group for detecting positive CAC were 100% and 97.4%, respectively (k = 0.980). The CAC score for the ULDSa-3mm and ULDSa-1.5mm groups demonstrated excellent agreement with the CACQr-3mm group (ICC = 0.992, 0.990, respectively), with a mean difference of -12.3 and - 12.4. The agreement of risk categorization based on absolute and percentile CAC score between the ULDSa-1.5mm and CACQr-3mm groups was excellent (weighted k = 0.954, 0.983, respectively), and risk reclassification rates were low (3.5%, 2.8%, respectively). The effective dose was reduced by approximately 77.2% for the ULD-CT compared to the CAC-CT (0.18 mSv vs. 0.79 mSv, p < 0.001).

CONCLUSION

Reconstruction with a 1.5-mm slice thickness and kV-independent iterative algorithmic protocol in ULD-CT yielded excellent agreement in CAC score quantification and risk categorization compared with ECG-triggered CAC-CT.

Assessment of Subclinical Atherosclerosis in Asymptomatic People In Vivo: Measurements Suitable for Biomarker and Mendelian Randomization Studies

BACKGROUND

One strategy to reduce the burden of cardiovascular disease is the early detection and treatment of atherosclerosis. This has led to significant interest in studies of subclinical atherosclerosis, using different phenotypes, not all of which are accurate reflections of the presence of asymptomatic atherosclerotic plaques. The aim of part 2 of this series is to provide a review of the existing literature on purported measures of subclinical disease and recommendations concerning which tests may be appropriate in the prevention of incident cardiovascular disease.

METHODS

We conducted a critical review of measurements used to infer the presence of subclinical atherosclerosis in the major conduit arteries and focused on the predictive value of these tests for future cardiovascular events, independent of conventional cardiovascular risk factors, in asymptomatic people. The emphasis was on studies with >10 000 person-years of follow-up, with meta-analysis of results reporting adjusted hazard ratios (HRs) with 95% CIs. The arterial territories were limited to carotid, coronary, aorta, and lower limb arteries.

RESULTS

In the carotid arteries, the presence of plaque (8 studies) was independently associated with future stroke (pooled HR, 1.89 [1.04-3.44]) and cardiac events (7 studies), with a pooled HR, 1.77 (1.19-2.62). Increased coronary artery calcium (5 studies) was associated with the risk of coronary heart disease events, pooled HR, 1.54 (1.07-2.07) and increasing severity of calcification (by Agaston score) was associated with escalation of risk (13 studies). An ankle/brachial index (ABI) of <0.9, the pooled HR for cardiovascular death from 7 studies was 2.01 (1.43-2.81). There were insufficient studies of either, thoracic or aortic calcium, aortic diameter, or femoral plaque to synthesize the data based on consistent reporting of these measures.

CONCLUSIONS

The presence of carotid plaque, coronary artery calcium, or abnormal ankle pressures seems to be a valid indicator of the presence of subclinical atherosclerosis and may be considered for use in biomarker, Mendelian randomization and similar studies.

Fusion Modeling: Combining Clinical and Imaging Data to Advance Cardiac Care

In addition to the traditional clinical risk factors, an increasing amount of imaging biomarkers have shown value for cardiovascular risk prediction. Clinical and imaging data are captured from a variety of data sources during multiple patient encounters and are often analyzed independently. Initial studies showed that fusion of both clinical and imaging features results in superior prognostic performance compared with traditional scores. There are different approaches to fusion modeling, combining multiple data resources to optimize predictions, each with its own advantages and disadvantages. However, manual extraction of clinical and imaging data is time and labor intensive and often not feasible in clinical practice. An automated approach for clinical and imaging data extraction is highly desirable. Convolutional neural networks and natural language processing can be utilized for the extraction of electronic medical record data, imaging studies, and free-text data. This review outlines the current status of cardiovascular risk prediction and fusion modeling; and in addition gives an overview of different artificial intelligence approaches to automatically extract data from images and electronic medical records for this purpose.

Assessment of Normal Systolic Blood Pressure Maintenance with the Risk of Coronary Artery Calcification Progression in Asymptomatic Metabolically Healthy Korean Adults with Normal Weight, Overweight, and Obesity

Metabolically healthy obesity (MHO) is known to have a close association with subclinical coronary atherosclerosis. Despite recent data on the benefit of intensive systolic blood pressure (SBP) control in diverse clinical conditions, little is known regarding the association of normal SBP maintenance (SBP_maintain) with coronary artery calcification (CAC) progression in MHO. This study included 2724 asymptomatic adults (48.8 ± 7.8 years; 77.9% men) who had no metabolic abnormalities except overweight and obesity. Participants with normal weight (44.2%), overweight (31.6%), and obesity (24.2%) were divided into two groups: normal SBP_maintain (follow-up SBP < 120 mm Hg) and ≥elevated SBP_maintain (follow-up SBP ≥ 120 mm Hg). CAC progression was defined using the SQRT method, a difference of ≥2.5 between the square root (√) of the baseline and follow-up coronary artery calcium score. During a mean follow-up of 3.4 years, the proportion of normal SBP_maintain (76.2%, 65.2%, and 59.1%) and the incidence of CAC progression (15.0%, 21.3%, and 23.5%) was different in participants with normal weight, overweight, and obesity (all p < 0.05, respectively). The incidence of CAC progression was lower in the normal SBP_maintain group than in the ≥elevated SBP_maintain group in only participants with obesity (20.8% vs. 27.4%, p = 0.048). In multiple logistic models, compared to participants with normal weight, those with obesity had a higher risk of CAC progression. Normal SBP_maintain was independently associated with the decreased risk of CAC progression in participants with obesity. MHO had a significant association with CAC progression. Normal SBP_maintain reduced the risk of CAC progression in asymptomatic adults with MHO.

Risk Factors for Incident Coronary Artery Calcium in Younger (Age 32 to 45 Years) Versus Intermediate (46 to 64 Years) Versus Older (65 to 84 Years) Persons

The prognostic value of traditional atherosclerotic cardiovascular disease (ASCVD) risk factors may decrease with age. We sought to determine whether the association between traditional ASCVD risk factors and incident coronary artery calcium (CAC) differs for younger versus older persons. We included 5,108 participants with baseline CAC = 0. Repeat CAC scoring occurred over 3 to 11 years of follow-up. Multivariable Cox proportional hazards regression assessed the association between traditional risk factors and incident CAC in young (32 to 45 years), middle-aged (46 to 64 years), and older adults (65 to 84 years). A total of 61% of the participants were women and 37% were Black. The proportion with incident CAC ranged from 22% among young adults, 34% for middle-aged adults, and 45% for older adults. In young adults, traditional risk factors were significantly associated with incident CAC except for diastolic blood pressure and high-density lipoprotein (HDL) cholesterol, whereas only total cholesterol/HDL cholesterol ≥3.5 (p = 0.04) was significantly associated with incident CAC in older persons. Non-HDL cholesterol (p = 0.02) was more strongly associated with incident CAC in young (hazard ratio [HR] 1.20, 95% confidence interval [CI] 1.09 to 1.31) and middle aged (HR 1.14, 95% CI 1.07 to 1.23) compared to older adults (HR 1.11, 95% CI 0.99 to 1.23). When added to demographics, traditional risk factors provided a greater C-statistic improvement for incident CAC prediction in young (0.752, +0.070, p <0.001) versus middle-aged (0.645, +0.054, p <0.001) and older adults (0.597,+0.025, p = 0.08). In conclusion, traditional risk factors more strongly predict incident CAC in young compared to older adults, underlining the importance of primordial prevention through middle age while identifying the challenges of ASCVD risk assessment in older persons.

Association of Cardiovascular Health Through Young Adulthood With Genome-Wide DNA Methylation Patterns in Midlife: The CARDIA Study

BACKGROUND

Cardiovascular health (CVH) from young adulthood is strongly associated with an individual's future risk of cardiovascular disease (CVD) and total mortality. Defining epigenomic biomarkers of lifelong CVH exposure and understanding their roles in CVD development may help develop preventive and therapeutic strategies for CVD.

METHODS

In 1085 CARDIA study (Coronary Artery Risk Development in Young Adults) participants, we defined a clinical cumulative CVH score that combines body mass index, blood pressure, total cholesterol, and fasting glucose measured longitudinally from young adulthood through middle age over 20 years (mean age, 25-45). Blood DNA methylation at >840 000 methylation markers was measured twice over 5 years (mean age, 40 and 45). Epigenome-wide association analyses on the cumulative CVH score were performed in CARDIA and compared in the FHS (Framingham Heart Study). We used penalized regression to build a methylation-based risk score to evaluate the risk of incident coronary artery calcification and clinical CVD events.

RESULTS

We identified 45 methylation markers associated with cumulative CVH at false discovery rate <0.01 (P=4.7E-7-5.8E-17) in CARDIA and replicated in FHS. These associations were more pronounced with methylation measured at an older age. CPT1A, ABCG1, and SREBF1 appeared as the most prominent genes. The 45 methylation markers were mostly located in transcriptionally active chromatin and involved lipid metabolism, insulin secretion, and cytokine production pathways. Three methylation markers located in genes SARS1, SOCS3, and LINC-PINT statistically mediated 20.4% of the total effect between CVH and risk of incident coronary artery calcification. The methylation risk score added information and significantly (P=0.004) improved the discrimination capacity of coronary artery calcification status versus CVH score alone and showed association with risk of incident coronary artery calcification 5 to 10 years later independent of cumulative CVH score (odds ratio, 1.87; P=9.66E-09). The methylation risk score was also associated with incident clinical CVD in FHS (hazard ratio, 1.28; P=1.22E-05).

CONCLUSIONS

Cumulative CVH from young adulthood contributes to midlife epigenetic programming over time. Our findings demonstrate the role of epigenetic markers in response to CVH changes and highlight the potential of epigenomic markers for precision CVD prevention, and earlier detection of subclinical CVD, as well.

Coronary artery calcium incidence and changes using direct plaque measurements: The MASALA study

BACKGROUND AND AIMS

We aimed to identify predictors of change in direct measures of coronary artery calcium (CAC) volume and density in South Asian participants.

METHODS

We used data from participants in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study with prevalent CAC and direct measures of CAC by serial computed tomography (CT) exams (2010-2013, 2016-2018). We examined the distribution of incident CAC volume and peak density, as well as progression and identified risk factors for progression of change in volume and density in multivariable models.

RESULTS

The study cohort consisted of 102 participants with incident CAC and 285 with CAC progression. CAC volume and density were highest, and incident CAC was most common in the left anterior descending artery (LAD). The greatest progression in volume was in the right coronary artery and the greatest change in density was in the left main. In linear regression models for CAC progression adjusted for baseline density, volume, risk factors, smoking (β +190.1, p = 0.02), baseline volume (β +0.24 per mm³, p < 0.01), and scan interval (β +0.15 per day, p = 0.01) were associated with change in total volume whereas Lp(a) (β +0.81 per mg/dL, p = 0.03), exercise (β +0.19 per 10 MET-min/week, p = 0.01), and baseline volume (β +0.15 per mm³, p < 0.01) and density (β -0.55 per unit, p < 0.01) were associated with change in total density.

CONCLUSIONS

In this South Asian cohort, smoking was associated with CAC volume progression, while Lp(a) and exercise were associated with progression of peak CAC density.

Low-dose coronary calcium scoring CT using a dedicated reconstruction filter for kV-independent calcium measurements

In this prospective, pilot study, we tested a kV-independent coronary artery calcium scoring CT protocol, using a novel reconstruction kernel (Sa36f). From December 2018 to November 2019, we performed an additional research scan in 61 patients undergoing clinical calcium scanning. For the standard protocol (120 kVp), images were reconstructed with a standard, medium-sharp kernel (Qr36d). For the research protocol (automated kVp selection), images were reconstructed with a novel kernel (Sa36f). Research scans were sequentially performed using a higher (cohort A, n = 31) and a lower (cohort B, n = 30) dose optimizer setting within the automatic system with customizable kV selection. Agatston scores, coronary calcium volumes, and radiation exposure of the standard and research protocol were compared. A phantom study was conducted to determine inter-scan variability. There was excellent correlation for the Agatston score between the two protocols (r = 0.99); however, the standard protocol resulted in slightly higher Agatston scores (29.4 [0-139.0] vs 17.4 [0-158.2], p = 0.028). The median calcium volumes were similar (11.5 [0-109.2] vs 11.2 [0-118.0] mm³; p = 0.176), and the number of calcified lesions was not significantly different (p = 0.092). One patient was reclassified to another risk category. The research protocol could be performed at a lower kV and resulted in a substantially lower radiation exposure, with a median volumetric CT dose index of 4.1 vs 5.2 mGy, respectively (p < 0.001). Our results showed that a consistent coronary calcium scoring can be achieved using a kV-independent protocol that lowers radiation doses compared to the standard protocol. KEY POINTS: • The Sa36f kernel enables kV-independent Agatston scoring without changing the original Agatston weighting threshold. • Agatston scores and calcium volumes of the standard and research protocols showed an excellent correlation. • The research protocol resulted in a significant reduction in radiation exposure with a mean reduction of 22% in DLP and 25% in CTDI_vol.

Tube voltage-independent coronary calcium scoring on a first-generation dual-source photon-counting CT-a proof-of-principle phantom study

To evaluate the accuracy of coronary artery calcium (CAC) scoring at various tube voltages and different monoenergetic image reconstructions on a first-generation dual-source photon-counting detector CT (PCD-CT). A commercially available anthropomorphic chest phantom with calcium inserts was scanned at different tube voltages (90 kV, Sn100kV, 120 kV, and Sn140kV) on a first-generation dual-source PCD-CT system with quantum technology using automatic exposure control with an image quality (IQ) level of 20. The same phantom was also scanned on a conventional energy-integrating detector CT (120 kV; weighted filtered back projection) for reference. Extension rings were used to emulate different patient sizes. Virtual monoenergetic images at 65 keV and 70 keV applying different levels of quantum iterative reconstruction (QIR) were reconstructed from the PCD-CT data sets. CAC scores were determined and compared to the reference. Radiation doses were noted. At an IQ level of 20, radiation doses ranged between 1.18 mGy and 4.64 mGy, depending on the tube voltage and phantom size. Imaging at 90 kV or Sn100kV was associated with a size-dependent radiation dose reduction between 23% and 48% compared to 120 kV. Tube voltage adapted image reconstructions with 65 keV and QIR 3 at 90 kV and with 70 keV and QIR 1 at Sn100kV allowed to calculate CAC scores comparable to conventional EID-CT scans with a percentage deviation of ≤ 5% for all phantom sizes. Our phantom study indicates that CAC scoring with dual-source PCD-CT is accurate at various tube voltages, offering the possibility of substantial radiation dose reduction.

Automated coronary artery calcium scoring using nested U-Net and focal loss

Coronary artery calcium (CAC) is a great risk predictor of the atherosclerotic cardiovascular disease and CAC scores can be used to stratify the risk of heart disease. Current clinical analysis of CAC is performed using onsite semiautomated software. This semiautomated CAC analysis requires experienced radiologists and radiologic technologists and is both demanding and time-consuming. The purpose of this study is to develop a fully automated CAC detection model that can quantify CAC scores. A total of 1,811 cases of cardiac examinations involving contrast-free multidetector computed tomography were retrospectively collected. We divided the database into the Training Data Set, Validation Data Set, Testing Data Set 1, and Testing Data Set 2. The Training, Validation, and Testing Data Set 1 contained cases with clinically detected CAC; Testing Data Set 2 contained those without detected calcium. The intraclass correlation coefficients between the overall standard and model-predicted scores were 1.00 for both the Training Data Set and Testing Data Set 1. In Testing Data Set 2, the model was able to detect clinically undetected cases of mild calcium. The results suggested that the proposed model’s automated detection of CAC was highly consistent with clinical semiautomated CAC analysis. The proposed model demonstrated potential for clinical applications that can improve the quality of CAC risk stratification.

Plasma lipid profiles in early adulthood are associated with epigenetic aging in the Coronary Artery Risk Development in Young Adults (CARDIA) Study

Background

GrimAge acceleration (GAA), an epigenetic marker that represents physiologic aging, is associated with atherosclerotic cardiovascular disease. However, the associations between early adulthood lipid levels and GAA in midlife are unknown. Also, it is unknown whether GAA mediates the associations between lipid levels in young adults and subclinical atherosclerosis in midlife.

Results

We estimated measures of epigenetic age acceleration in 1118 White and Black participants from the Coronary Artery Risk Development in Young Adults (CARDIA) Study at examination years (Y) 15 and 20. We used multivariable regression models to examine associations of Y15 and Y20 GAA estimates with plasma lipid levels measured at prior examination years (Y0, Y5, and Y10) and concurrently: triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels. Mediation analysis was used to assess the extent to which GAA may mediate associations between plasma lipids and coronary artery calcification (CAC). In our study each 1-SD higher cumulative TG level was associated with an average 0.73 ± 0.12 years older GAA. Each 1-SD higher cumulative HDL-C level was associated with an average 0.57 ± 0.17 years younger GAA. Stratified analyses showed that the associations between TG and GAA were stronger among female and Black participants and the associations between HDL-C and GAA were stronger among female and White participants. GAA statistically mediated 17.4% of the association of cumulative TG with CAC.

Conclusions

High TG and low HDL-C in early adulthood are associated with accelerated epigenetic aging by midlife. Increased epigenetic age acceleration may partially mediate the associations between high TG levels and the presence of subclinical atherosclerosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01222-2.

Associations of endogenous sex hormone levels with the prevalence and progression of valvular and thoracic aortic calcification in the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND AND AIMS

Sex hormones (SH) may contribute to sex differences in cardiovascular disease (CVD). High free testosterone (T) and low sex hormone binding globulin (SHBG) have been associated with progression of coronary artery calcification in women. We now examined the association of SH with extra-coronary calcification (ECC) prevalence and progression among MESA participants.

METHODS

We studied 2,737 postmenopausal women and 3,130 men free of clinical CVD with baseline SH levels. ECC measurements [ascending and descending thoracic aortic calcification (ATAC, DTAC), mitral annular calcification (MAC), aortic valve calcification (AVC)] were obtained by computed tomography at baseline and after 2.4 ± 0.9 years. We used multivariable Poisson regression to evaluate associations with ECC prevalence and incidence (Agatston scores >0) and linear mixed effects models for ECC progression, per 1-SD increment in log(SH) in women and men separately.

RESULTS

The mean age was 65 ± 9 and 62 ± 10 years for women and men, respectively. In women, greater free T and lower SHBG were associated with MAC incidence in a demographic-adjusted model only. In men, lower free T was associated with MAC prevalence, DTAC incidence and progression, while greater SHBG was associated with MAC prevalence and DTAC progression after further adjusting for CVD risk factors.

CONCLUSIONS

In this diverse cohort free of CVD, we found some associations of SH with ECC measures. In particular, free T was inversely associated with prevalent MAC and DTAC progression in men independent of CVD risk factors. SH may influence vascular calcification, but further work is needed to understand clinical implications of these findings.

Association of Abdominal Aorta Calcium and Coronary Artery Calcium with Incident Cardiovascular and Coronary Heart Disease Events in Black and White Middle-Aged People: The Coronary Artery Risk Development in Young Adults Study

Background Assessing coronary artery calcium (CAC) is among AHA/ACC prevention guidelines for people at least 40 years old at intermediate risk for coronary heart disease (CHD). To study enhanced risk stratification, we investigated the predictive value of abdominal aorta calcium (AAC) relative to CAC for cardiovascular disease (CVD) and CHD events in Black and White early middle-aged participants, initially free of overt CVD. Methods and Results In the CARDIA (Coronary Artery Risk Development in Young Adults) study, a multi-center, community-based, longitudinal cohort study of CVD risk, the CAC and AAC scores were assessed in 3011 participants in 2010-2011 with follow-up until 2019 for incident CVD and CHD events. Distributions and predictions, overall and by race, were computed. During the 8-year follow-up, 106 incident CVD events (55 were CHD) occurred. AAC scores tended to be much higher than CAC scores. AAC scores were higher in Black women than in White women. CAC predicted CVD with HR 1.77 (1.52-2.06) and similarly for AAC, while only CAC predicted CHD. After adjustment for risk factors and calcium in the other arterial bed, the association of CAC with CVD was independent of risk factors and AAC, while the association of AAC with CVD was greatly attenuated. However, AAC predicted incident CVD when CAC was 0. Prediction did not vary by race. Conclusions AAC predicted CVD nearly as strongly as CAC and could be especially useful as a diagnostic tool when it is an incidental finding or when no CAC is found.

Risk Markers for Limited Coronary Artery Calcium in Persons With Significant Aortic Valve Calcium (From the Multi-ethnic Study of Atherosclerosis)

The early stages of aortic valve calcification (AVC) and coronary artery calcification (CAC) include shared ASCVD risk factors, yet there is considerable heterogeneity between the burden of AVC, and CAC. We sought to identify the markers associated with limited CAC among persons with significant AVC. There were 325 participants from the Multi-Ethnic Study of Atherosclerosis without clinical ASCVD and with AVC ≥100 Agatston units (AU) at Visit 1. Multivariable-adjusted prevalence ratios for limited CAC (0 to 99 AU) were calculated using modified Poisson regression. Participants had a mean age of 72.1 years, median AVC score of 209, and 34% were women. A total of 133 (41%) participants had CAC <100, of whom 46/133 had CAC = 0. Younger age (PR = 1.40, 95% CI: 1.22 to 1.62, per 10-years), female gender (PR = 1.68, 95% CI: 1.28 to 2.20), and low 10-year ASCVD risk (PR = 2.30, 95% CI: 1.85 to 2.85) were most strongly associated with limited CAC. Neither a normal lipoprotein(a) nor normal measures of inflammation were significantly associated with limited CAC. Lower serum phosphate (PR = 1.15, 95% CI: 1.01 to 1.31; per 0.5 mg/dl lower) and calcium-phosphate product (PR = 1.16, 95% CI: 1.02 to 1.34; per SD lower) were associated with an approximately 15% higher prevalence of limited CAC. In conclusion, more than 40% of persons with significant AVC had CAC. Beyond traditional risk factors, lower serum phosphate, and lower calcium-phosphate product were associated with a higher prevalence of limited CAC.

Association between blood pressure classification defined by the 2017 ACC/AHA guidelines and coronary artery calcification progression in an asymptomatic adult population

Aims

Coronary artery calcium score (CACS) is widely used for cardiovascular risk stratification in asymptomatic population. We assessed the association of new blood pressure (BP) classification using the 2017 American College of Cardiology/American Heart Association guidelines with coronary artery calcification (CAC) progression according to age in asymptomatic adults.

Methods and results

Overall, 10 839 asymptomatic Korean adults (23.4% aged ≤45 years) who underwent at least two CACS evaluations for health check-up were enrolled. Participants were categorized by age (≤45 and >45 years) and BP [normal (<120/<80 mmHg, untreated), elevated (120-129/<80 mmHg, untreated), Stage 1 hypertension (untreated BP 130-139/80-89 mmHg) or Stage 2 hypertension (BP ≥140/≥90 mmHg or anti-hypertensive use)] groups. CAC progression was defined as a difference of ≥2.5 between the square root (√) of the baseline and follow-up CACS. During a mean 3.3-year follow-up, the incidence of CAC progression was 13.5% and 36.3% in individuals aged ≤45 and >45 years, respectively. After adjustment for age, sex, diabetes, dyslipidaemia, obesity, current smoking, and baseline CACS, hazard ratios (95% confidence interval) for CAC progression in elevated BP, Stage 1 hypertension, and Stage 2 hypertension compared to normal BP were 1.43 (0.96-2.14) (P = 0.077), 1.64 (1.20-2.23) (P = 0.002), and 2.38 (1.82-3.12) (P < 0.001) in the ≤45 years group and 1.11 (0.95-1.30) (P = 0.179), 1.17 (1.04-1.32) (P = 0.009), and 1.52 (1.39-1.66) (P < 0.001) in the >45 years group, respectively.

Conclusion

Newly defined Stage 1 hypertension is independently associated with CAC progression in asymptomatic adults regardless of age.

Atherosclerotic cardiovascular disease events among statin eligible individuals with and without long-term healthy arterial aging

BACKGROUND AND AIMS

A large proportion of statin eligible candidates have a baseline absence of coronary artery calcium (CAC) and low 10-year atherosclerotic cardiovascular disease (ASCVD) risk. We sought to determine the proportion of statin eligible individuals who had long-term healthy arterial aging (persistent CAC = 0) and their examined 15-year ASCVD outcomes.

METHODS

We included 561 statin eligible candidates from the Multi-Ethnic Study of Atherosclerosis who were not on statin therapy with CAC = 0 at Visit 1 (2000-02) and underwent a subsequent CAC scan at Visit 5 (2010-11). Adjusted Cox proportional hazards regression assessed the association between persistent CAC = 0 and ASCVD events over 15.9 years.

RESULTS

Participants were on average 61.7 years old, 50% were women, and 43% maintained long-term CAC = 0. Individuals with an LDL-C ≥190 mg/dL (54%) and those with an ASCVD risk ≥20% (33%) had the highest and lowest proportion of persistent CAC = 0, respectively. There were 57 ASCVD events, and 15-year ASCVD event rates were low for individuals with and without healthy arterial aging (4.3 versus 8.6 per 1,000 persons-years), but the 10-year number needed to treat to prevent one ASCVD event differed by more than two fold (117 versus 54). In multivariable modeling, persistent CAC = 0 conferred a 51% lower risk of ASCVD compared to those with incident CAC (HR = 0.49, 95% CI: 0.27-0.90, p=0.02).

CONCLUSIONS

More than 40% of statin eligible individuals with baseline CAC = 0 had long-term healthy arterial aging. Statin eligible candidates with persistent CAC = 0 had a very low 15-year ASCVD risk, suggesting that statin therapy may be of limited benefit among this group of individuals.

The National Lipid Association scientific statement on coronary artery calcium scoring to guide preventive strategies for ASCVD risk reduction

An Expert Panel of the National Lipid Association reviewed the evidence related to the use of coronary artery calcium (CAC) scoring in clinical practice for adults seen for primary prevention of atherosclerotic cardiovascular disease. Recommendations for optimal use of this test in adults of various races/ethnicities, ages and multiple domains of primary prevention, including those with a 10-year ASCVD risk <20%, those with diabetes or the metabolic syndrome, and those with severe hypercholesterolemia were provided. Recommendations were also made on optimal timing for repeat calcium scoring after an initial test, use of CAC scoring in those taking statins, and its role in informing the clinician patient discussion on the benefit of aspirin and anti-hypertensive drug therapy. Finally, a vision is provided for the future of coronary calcium scoring.

Predicting Long-Term Absence of Coronary Artery Calcium in Metabolic Syndrome and Diabetes: The MESA Study

OBJECTIVES

The purpose of this study was to identify predictors of healthy arterial aging (long-term coronary artery calcification [CAC] of 0) among individuals with metabolic syndrome (MetS) or type 2 diabetes (T2D), which may improve primary prevention strategies.

BACKGROUND

Individuals with MetS or T2D have a heterogeneously increased risk of atherosclerotic cardiovascular disease and not all have a high-intermediate risk.

METHODS

We included 574 participants from the MESA (Multi-Ethnic Study of Atherosclerosis) with MetS or T2D who had CAC=0 at baseline and a repeat CAC scan 10 years later. Multivariable logistic regression assessed the association of traditional and novel atherosclerotic cardiovascular disease risk factors and the MetS severity score (based on the 5 MetS criteria) with healthy arterial aging.

RESULTS

The mean age of participants was 58.9 years, 67% were women, 422 participants had MetS, and 152 had T2D. The proportion with long-term CAC=0 was similar for MetS (42%) and T2D (44%). A younger age was the only individual low/normal traditional risk factor associated with an increased likelihood of long-term CAC=0 (odds ratio [OR]: 1.50; 95% confidence interval [CI]: 1.22 to 1.85 per 10-years younger). The strongest associations of nontraditional risk factors were observed for an absence of thoracic calcification (OR: 2.42; 95% CI: 1.24 to 4.72), absence of carotid plaque (OR: 1.81; 95% CI: 1.25 to 2.61), and among persons with a high sensitivity troponin <3 ng/ml (OR: 1.55; 95% CI: 1.01 to 2.38). In addition, persons with the lowest quartile MetS severity score had a substantially higher odds of healthy long-term CAC=0 (OR: 2.71; 95% CI: 1.27 to 5.76).

CONCLUSIONS

More than 40% of adults with MetS or T2D and baseline CAC=0 had long-term absence of CAC, which was most strongly associated with an absence of extracoronary atherosclerosis and a low MetS score. An optimal overall cardiovascular profile appears to be more important than an ideal value of any individual risk factor to maintain healthy arterial aging.

Coronary 18F-Fluoride Uptake and Progression of Coronary Artery Calcification

Supplemental Digital Content is available in the text.

Background

Positron emission tomography (PET) using ¹⁸F-sodium fluoride (¹⁸F-fluoride) to detect microcalcification may provide insight into disease activity in coronary atherosclerosis. This study aimed to investigate the relationship between ¹⁸F-fluoride uptake and progression of coronary calcification in patients with clinically stable coronary artery disease.

Methods

Patients with established multivessel coronary atherosclerosis underwent ¹⁸F-fluoride PET-computed tomography angiography and computed tomography calcium scoring, with repeat computed tomography angiography and calcium scoring at one year. Coronary PET uptake was analyzed qualitatively and semiquantitatively in diseased vessels by measuring maximum tissue-to-background ratio. Coronary calcification was quantified by measuring calcium score, mass, and volume.

Results

In a total of 183 participants (median age 66 years, 80% male), 116 (63%) patients had increased ¹⁸F-fluoride uptake in at least one vessel. Individuals with increased ¹⁸F-fluoride uptake demonstrated more rapid progression of calcification compared with those without uptake (change in calcium score, 97 [39–166] versus 35 [7–93] AU; P<0.0001). Indeed, the calcium score only increased in coronary segments with ¹⁸F-fluoride uptake (from 95 [30–209] to 148 [61–289] AU; P<0.001) and remained unchanged in segments without ¹⁸F-fluoride uptake (from 46 [16–113] to 49 [20–115] AU; P=0.329). Baseline coronary ¹⁸F-fluoride maximum tissue-to-background ratio correlated with 1-year change in calcium score, calcium volume, and calcium mass (Spearman ρ=0.37, 0.38, and 0.46, respectively; P<0.0001 for all). At the segmental level, baseline ¹⁸F-fluoride activity was an independent predictor of calcium score at 12 months (P<0.001). However, at the patient level, this was not independent of age, sex, and baseline calcium score (P=0.50).

Conclusions

Coronary ¹⁸F-fluoride uptake identifies both patients and individual coronary segments with more rapid progression of coronary calcification, providing important insights into disease activity within the coronary circulation. At the individual patient level, total calcium score remains an important marker of disease burden and progression.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02110303.

Predictors of coronary artery calcium incidence and progression: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

BACKGROUND AND AIMS

There are limited data on serial coronary artery calcium (CAC) assessments outside North American and European populations. We sought to investigate risk factors for CAC incidence and progression in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

METHODS

We included individuals with no prior cardiovascular disease and two CAC measurements in ELSA-Brasil. Incident CAC was defined as a baseline CAC of 0 followed by CAC >0 on the second study. CAC progression was defined according to multiple published criteria. We performed logistic and linear regression to identify risk factors for CAC incidence and progression. We also examined risk factor effect modification by baseline CAC (0 vs. >0).

RESULTS

A total of 2707 individuals were included (57% women, age 48.6 ± 7.7 years). Participants self-identified as white (55%), brown (24%), black (16%), Asian (4%) and Indigenous (1%). The mean period between CAC assessments was 5.1 ± 0.9 years. CAC incidence occurred in 282 (13.3%) of 2127 individuals with baseline CAC of 0. CAC progression occurred in 319 (55%) of 580 participants with baseline CAC >0. Risk factors for CAC incidence included older age, male sex, white race, hypertension, diabetes, higher BMI, smoking, lower HDL-C, higher LDL-C and triglycerides, and metabolic syndrome. Older age and elevated LDL-C were associated with CAC incidence, but not progression. Risk factors consistently associated with CAC progression were hypertension, diabetes, hypertriglyceridemia, and metabolic syndrome. On interaction testing, these four risk factors were more strongly associated with CAC progression as compared to CAC incidence.

CONCLUSIONS

CAC incidence was associated with multiple traditional risk factors, whereas the only risk factors associated with progression of CAC were hypertension, diabetes, hypertriglyceridemia, and metabolic syndrome.

High-pitch dual-source CT for coronary artery calcium scoring: A head-to-head comparison of non-triggered chest versus triggered cardiac acquisition

BACKGROUND

To determine the effect of low-dose, high-pitch non-electrocardiographic (ECG)-triggered chest CT on coronary artery calcium (CAC) detection, quantification and risk stratification, compared to ECG-triggered cardiac CT.

METHODS

We selected 1,000 participants from the ImaLife study, 50% with coronary calcification on cardiac CT. All participants underwent non-contrast cardiac CT followed by chest CT using third-generation dual-source technology. Reconstruction settings were equal for both acquisitions. CAC scores were determined by Agatston's method, and divided dichotomously (0, >0), and into risk categories (0, 1-99, 100-399, ≥400). We investigated the influence of heart rate and body mass index (BMI) on risk reclassification.

RESULTS

Positive CAC scores on cardiac CT ranged from 1 to 6926 (median 39). Compared to cardiac CT, chest CT had sensitivity of 0.96 (95%CI 0.94-0.98) and specificity of 0.99 (95%CI 0.97-0.99) for CAC detection (κ = 0.95). In participants with coronary calcification on cardiac CT, CAC score on chest CT was lower than on cardiac CT (median 30 versus 40, p˂0.001). Agreement in CAC-based risk strata was excellent (weighted κ = 0.95). Sixty-five cases (6.5%) were reclassified by one risk category in chest CT, with fifty-five (84.6%) shifting downward. Higher BMI resulted in higher reclassification rate (13% for BMI ≥30 versus 5.2% for BMI <30, p = 0.001), but there was no effect of heart rate.

CONCLUSION

Low-dose, high-pitch chest CT, using third-generation dual-source technology shows almost perfect agreement with cardiac CT in CAC detection and risk stratification. However, low-dose chest CT mainly underestimates the CAC score as compared to cardiac CT, and results in inaccurate risk categorization in BMI ≥30.

Association of Coronary Artery Calcium in Adults Aged 32 to 46 Years With Incident Coronary Heart Disease and Death

Importance

Coronary artery calcium (CAC) is associated with coronary heart disease (CHD) and cardiovascular disease (CVD); however, prognostic data on CAC are limited in younger adults.

Objective

To determine if CAC in adults aged 32 to 46 years is associated with incident clinical CHD, CVD, and all-cause mortality during 12.5 years of follow-up.

Design, Setting, and Participants

The Coronary Artery Risk Development in Young Adults (CARDIA) Study is a prospective community-based study that recruited 5115 black and white participants aged 18 to 30 years from March 25, 1985, to June 7, 1986. The cohort has been under surveillance for 30 years, with CAC measured 15 (n = 3043), 20 (n = 3141), and 25 (n = 3189) years after recruitment. The mean follow-up period for incident events was 12.5 years, from the year 15 computed tomographic scan through August 31, 2014.

Main Outcomes and Measures

Incident CHD included fatal or nonfatal myocardial infarction, acute coronary syndrome without myocardial infarction, coronary revascularization, or CHD death. Incident CVD included CHD, stroke, heart failure, and peripheral arterial disease. Death included all causes. The probability of developing CAC by age 32 to 56 years was estimated using clinical risk factors measured 7 years apart between ages 18 and 38 years.

Results

At year 15 of the study among 3043 participants (mean [SD] age, 40.3 [3.6] years; 1383 men and 1660 women), 309 individuals (10.2%) had CAC, with a geometric mean Agatston score of 21.6 (interquartile range, 17.3-26.8). Participants were followed up for 12.5 years, with 57 incident CHD events and 108 incident CVD events observed. After adjusting for demographics, risk factors, and treatments, those with any CAC experienced a 5-fold increase in CHD events (hazard ratio [HR], 5.0; 95% CI, 2.8-8.7) and 3-fold increase in CVD events (HR, 3.0; 95% CI, 1.9-4.7). Within CAC score strata of 1-19, 20-99, and 100 or more, the HRs for CHD were 2.6 (95% CI, 1.0-5.7), 5.8 (95% CI, 2.6-12.1), and 9.8 (95% CI, 4.5-20.5), respectively. A CAC score of 100 or more had an incidence of 22.4 deaths per 100 participants (HR, 3.7; 95% CI, 1.5-10.0); of the 13 deaths in participants with a CAC score of 100 or more, 10 were adjudicated as CHD events. Risk factors for CVD in early adult life identified those above the median risk for developing CAC and, if applied, in a selective CAC screening strategy could reduce the number of people screened for CAC by 50% and the number imaged needed to find 1 person with CAC from 3.5 to 2.2.

Conclusions and Relevance

The presence of CAC among individuals aged between 32 and 46 years was associated with increased risk of fatal and nonfatal CHD during 12.5 years of follow-up. A CAC score of 100 or more was associated with early death. Adults younger than 50 years with any CAC, even with very low scores, identified on a computed tomographic scan are at elevated risk of clinical CHD, CVD, and death. Selective use of screening for CAC might be considered in individuals with risk factors in early adulthood to inform discussions about primary prevention.

Implications of coronary artery calcium testing on risk stratification for lipid-lowering therapy according to the 2016 European Society of Cardiology recommendations: The MESA study

AIMS

The European Society of Cardiology (ESC) guideline on cardiovascular risk assessment considers coronary artery calcium a class B indication for risk assessment. We evaluated the degree to which coronary artery calcium can change the recommendation for individuals based on a change in estimated risk.

METHODS AND RESULTS

We stratified 5602 MESA participants according to the ESC recommendation as: no lipid-lowering treatment recommended ( N = 2228), consider lipid-lowering treatment if uncontrolled ( N = 1686), or lipid-lowering treatment recommended ( N = 1688). We evaluated the ability of coronary artery calcium to reclassify cardiovascular risk. Among the selected sample, 54% had coronary artery calcium of zero, 25% had coronary artery calcium of 1-100 and 21% had coronary artery calcium greater than 100. In the lipid-lowering treatment recommended group 31% had coronary artery calcium of zero, while in the lipid-lowering treatment if uncontrolled group about 50% had coronary artery calcium of zero. The cardiovascular mortality rate was 1.7%/10 years in the lipid-lowering treatment if uncontrolled, and 7.0%/10 years in the lipid-lowering treatment recommended group. The absence of coronary artery calcium was associated with 1.4%/10 years in the lipid-lowering treatment if uncontrolled group and 3.0%/10 years in the lipid-lowering treatment recommended group. Compared with coronary artery calcium of zero, any coronary artery calcium was associated with significantly higher cardiovascular mortality in the lipid-lowering treatment recommended group (9.0%/10 years), whereas only coronary artery calcium greater than 100 was significantly associated with a higher cardiovascular mortality in the lipid-lowering treatment if uncontrolled group (3.2%/10 years).

CONCLUSION

The absence of coronary artery calcium is associated with a low incidence of cardiovascular mortality or coronary heart disease events even in individuals in whom lipid-lowering therapy is recommended. A significant proportion of individuals deemed to be candidates for lipid-lowering therapy might be reclassified to a lower risk group with the use of coronary artery calcium.

Ten-year association of coronary artery calcium with atherosclerotic cardiovascular disease (ASCVD) events: the multi-ethnic study of atherosclerosis (MESA)

Aims

While coronary artery calcium (CAC) has been extensively validated for predicting clinical events, most outcome studies of CAC have evaluated coronary heart disease (CHD) rather than atherosclerotic cardiovascular disease (ASCVD) events (including stroke). Also, virtually all CAC studies are of short- or intermediate-term follow-up, so studies across multi-ethnic cohorts with long-term follow-up are warranted prior to widespread clinical use. We sought to evaluate the contribution of CAC using the population-based MESA cohort with over 10 years of follow-up for ASCVD events, and whether the association of CAC with events varied by sex, race/ethnicity, or age category.

Methods and results

We utilized MESA, a prospective multi-ethnic cohort study of 6814 participants (51% women), aged 45-84 years, free of clinical CVD at baseline. We evaluated the relationship between CAC and incident ASCVD using Cox regression models adjusted for age, race/ethnicity, sex, education, income, cigarette smoking status, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, diabetes, lipid-lowering medication, systolic blood pressure, antihypertensive medication, intentional physical exercise, and body mass index. Only the first event for each individual was used in the analysis. Overall, 500 incident ASCVD (7.4%) events were observed in the total study population over a median of 11.1 years. Hard ASCVD included 217 myocardial infarction, 188 strokes (not transient ischaemic attack), 13 resuscitated cardiac arrest, and 82 CHD deaths. Event rates in those with CAC = 0 Agatston units ranged from 1.3% to 5.6%, while for those with CAC > 300, the 10-year event rates ranged from 13.1% to 25.6% across different age, gender, and racial subgroups. At 10 years of follow-up, all participants with CAC > 100 were estimated to have >7.5% risk regardless of demographic subset. Ten-year ASCVD event rates increased steadily across CAC categories regardless of age, sex, or race/ethnicity. For each doubling of CAC, we estimated a 14% relative increment in ASCVD risk, holding all other risk factors constant. This association was not significantly modified by age, sex, race/ethnicity, or baseline lipid-lowering use.

Conclusions

Coronary artery calcium is associated strongly and in a graded fashion with 10-year risk of incident ASCVD as it is for CHD, independent of standard risk factors, and similarly by age, gender, and ethnicity. While 10-year event rates in those with CAC = 0 were almost exclusively below 5%, those with CAC ≥ 100 were consistently above 7.5%, making these potentially valuable cutpoints for the consideration of preventive therapies. Coronary artery calcium strongly predicts risk with the same magnitude of effect in all races, age groups, and both sexes, which makes it among the most useful markers for predicting ASCVD risk.

High-pitch versus sequential mode for coronary calcium in individuals with a high heart rate: Potential for dose reduction

BACKGROUND

To determine the impact of high-pitch spiral acquisition on radiation dose and cardiovascular disease (CVD) risk stratification by coronary artery calcium (CAC) assessment with computed tomography in individuals with a high heart rate.

METHODS

Of the ROBINSCA trial, 1990 participants with regular rhythm and heart rates >65 beats per minute (bpm) were included. As reference, 390 participants with regular heart rates ≤65 bpm were used. All participants underwent prospectively electrocardiographically(ECG)-triggered imaging of the coronary arteries using dual source CT at 120 kVp, 80 ref mAs using both high-pitch spiral mode and sequential mode. Radiation dose, Agatston score, number of positive scores, as well as median absolute difference of the Agatston score were determined and participants were stratified into CVD risk categories.

RESULTS

A similar percentage of participants with low heart rates and high heart rates had a positive CAC score in data sets acquired in high-pitch spiral (low heart rate: 57.7%, high heart rate: 55.8%) and sequential mode (58.0%, 54.7%, p = n.s.). The median absolute difference in Agatston scores between acquisition modes was 14.2% and 9.2%, for the high and low heart rate groups, respectively. Excellent agreement for risk categorization between the two data acquisition modes was found for the high (κ = 0.927) and low (κ = 0.946) heart rate groups. Radiation dose was 48% lower for high-pitch spiral versus sequential acquisitions.

CONCLUSION

Radiation dose for the quantification of coronary calcium can be reduced by 48% when using the high-pitch spiral acquisition mode compared to the sequential mode in participants with a regular high heart rate. CVD risk stratification agreement between the two modes of data acquisition is excellent.

Genome-wide association study of coronary artery calcified atherosclerotic plaque in African Americans with type 2 diabetes

Background

Coronary artery calcified atherosclerotic plaque (CAC) predicts cardiovascular disease (CVD). Despite exposure to more severe conventional CVD risk factors, African Americans (AAs) are less likely to develop CAC, and when they do, have markedly lower levels than European Americans. Genetic factors likely contribute to the observed ethnic differences. To identify genes associated with CAC in AAs with type 2 diabetes (T2D), a genome-wide association study (GWAS) was performed using the Illumina 5 M chip in 691 African American-Diabetes Heart Study participants (AA-DHS), with replication in 205 Jackson Heart Study (JHS) participants with T2D. Genetic association tests were performed on the genotyped and 1000 Genomes-imputed markers separately for each study, and combined in a meta-analysis.

Results

Single nucleotide polymorphisms (SNPs), rs11353135 (2q22.1), rs16879003 (6p22.3), rs5014012, rs58071836 and rs10244825 (all on chromosome 7), rs10918777 (9q31.2), rs13331874 (16p13.3) and rs4459623 (18q12.1) were associated with presence and/or quantity of CAC in the AA-DHS and JHS, with meta-analysis p-values ≤8.0 × 10⁻⁷. The strongest result in AA-DHS alone was rs6491315 in the 13q32.1 region (parameter estimate (SE) = −1.14 (0.20); p-value = 9.1 × 10⁻⁹). This GWAS peak replicated a previously reported AA-DHS CAC admixture signal (rs7492028, LOD score 2.8).

Conclusions

Genetic association between SNPs on chromosomes 2, 6, 7, 9, 16 and 18 and CAC were detected in AAs with T2D from AA-DHS and replicated in the JHS. These data support a role for genetic variation on these chromosomes as contributors to CAC in AAs with T2D, as well as to variation in CAC between populations of African and European ancestry.

Electronic supplementary material

The online version of this article (10.1186/s12863-017-0572-9) contains supplementary material, which is available to authorized users.

Alcohol Use and Cardiovascular Disease Risk in Patients With Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

Cardiovascular disease (CVD) is the leading cause of death among patients with nonalcoholic fatty liver disease (NAFLD). Moderate drinking (vs abstinence) is associated with lower risk of CVD in the general population. We assessed whether alcohol use is associated with CVD risk in patients with NAFLD.

METHODS

We analyzed data from participants in the Coronary Artery Risk Development in Young Adults longitudinal cohort study of 5115 black and white young adults, 18-30 years old, recruited from 4 cities in the United States from 1985 through 1986. Participants self-reported alcohol use at study entry and then again after 15, 20, and 25 years. At year 25 (2010-2011), participants underwent computed tomography examination of the thorax and abdomen and tissue Doppler echocardiography with myocardial strain measured by speckle tracking. Coronary artery calcification was defined as an Agatston score above 0. NAFLD was defined as liver attenuation <51 Hounsfield Units after exclusions. Drinkers reported 1-21 (men) or 1-14 (women) standard drinks/week at years 15, 20, or 25. Nondrinkers reported no alcohol use at years 15, 20, and 25.

RESULTS

Of the 570 participants with NAFLD (mean age, 50 years; 54% black; 46% female), 332 (58%) were drinkers; significantly higher proportions of drinkers were white, male, and with higher levels of education compared with nondrinkers (P < .05 for all). Higher proportions of drinkers had obesity, diabetes, and metabolic syndrome compared with nondrinkers (P < .01). There was no difference in liver attenuation between groups (P = .12). After multivariable adjustment, there was no association between alcohol use and CVD risk factors (diabetes, hypertension, hyperlipidemia) or subclinical CVD measures (coronary artery calcification, early transmitral velocity/late (atrial) transmitral velocity (E/A) ratio, global longitudinal strain).

CONCLUSIONS

In a population-based sample of individuals with NAFLD in midlife, prospectively assessed alcohol use is not associated with significant differences in risk factors for CVD or markers of subclinical CVD. In contrast to general population findings, alcohol use may not reduce the risk of CVD in patients with NAFLD.

The Apolipoprotein L1 Gene and Cardiovascular Disease

Relative to those with European ancestry, African Americans have an excess incidence of nondiabetic chronic kidney disease predominantly due to two coding renal-risk variants in the apolipoprotein L1 gene (APOL1). This APOL1-kidney disease association is independent of systemic hypertension or blood pressure. Recent reports describe extra-renal effects of the APOL1 G1 and G2 renal-risk variants on cardiovascular disease (CVD), subclinical atherosclerosis, lipoprotein particle concentrations, and survival. However, results have been less consistent than those seen in kidney disease, and the observed APOL1 associations with CVD vary from risk to protective. This manuscript reviews the relationships between APOL1 renal-risk variants and CVD, with an emphasis on study-specific factors that may have contributed to disparate observations. It is possible that APOL1 renal-risk variants impact the systemic vasculature, not only the kidneys. As novel therapies for APOL1-associated nephropathy are developed, APOL1 variant protein effects on large blood vessels and risk of CVD will need to be considered.

Progression of coronary artery calcium in Japanese American men and white men in the ERA JUMP study

BACKGROUND

Progression of coronary artery calcium (CAC) is associated with increased risk of coronary heart disease (CHD) and is reported to be greater in whites than blacks, Hispanics, and Chinese in the US. Our objective was to compare progression of CAC between Japanese Americans and whites.

METHODS

Population-based sample of 303 Japanese American men and 310 white men aged 40-49years, free of clinical cardiovascular disease at baseline, were examined for CAC at baseline (2004-2007) and follow-up (2008-2013). Progression of CAC was defined as change in coronary calcium scores (CCS) in participants with baseline CCS>0 and incident CAC in participants with baseline CCS=0. Multiple linear regression and relative risk regression were used to compare change in CCS scores and incident CAC between the two races, respectively.

RESULTS

Japanese American men had significantly greater annual change in CCS than white men (median [interquartile range]: 11.3 Agatston units [1.4, 24.9] vs 2.5 [-0.22, 14.5]) in the unadjusted analyses. After adjusting for cardiovascular risk factors and follow-up time, change in CCS (beta±CI) and incidence rate ratio of CAC was similar in Japanese American men and white men: -0.12 (-0.34, 0.15) and (0.87 [95% CI: 0.20, 3.9]), respectively.

CONCLUSIONS

In contrast to previously reported greater progression of CAC in whites than other races, we found a similar progression of CAC in Japanese American men as white men. Our study identifies Japanese American men as a target group for prevention of CHD. Large prospective studies are warranted to confirm these findings.

Coronary Artery Calcium and Carotid Artery Intima Media Thickness and Plaque: Clinical Use in Need of Clarification

Atherosclerosis begins in early life and has a long latent period prior to onset of clinical disease. Measures of subclinical atherosclerosis, therefore, may have important implications for research and clinical practice of atherosclerotic cardiovascular disease (ASCVD). In this review, we focus on coronary artery calcium (CAC) and carotid artery intima-media thickness (cIMT) and plaque as many population-based studies have investigated these measures due to their non-invasive features and ease of administration. To date, a vast majority of studies have been conducted in the US and European countries, in which both CAC and cIMT/plaque have been shown to be associated with future risk of ASCVD, independent of conventional risk factors. Furthermore, these measures improve risk prediction when added to a global risk prediction model, such as the Framingham risk score. However, no clinical trial has assessed whether screening with CAC or cIMT/plaque will lead to improved clinical outcomes and healthcare costs. Interestingly, similar levels of CAC or cIMT/plaque among various regions and ethnic groups may in fact be associated with significantly different levels of absolute risk of ASCVD. Therefore, it remains to be determined whether measures of subclinical atherosclerosis improve risk prediction in non-US/European populations. Although CAC and cIMT/plaque are promising surrogates of ASCVD in research, we conclude that their use in clinical practice, especially as screening tools for primary prevention in asymptomatic adults, is premature due to many vagaries that remain to be clarified.

Impact of Advanced Modeled Iterative Reconstruction on Coronary Artery Calcium Quantification

RATIONALE AND OBJECTIVES

To evaluate the influence of advanced modeled iterative reconstruction (ADMIRE) on the coronary artery calcium (CAC) scores by computed tomography (CT).

MATERIALS AND METHODS

Sixty patients underwent CAC imaging with dual-source 192-slice CT. Agatston, volume and mass score were calculated from filtered back projection (FBP) and iterative reconstructions with different levels of ADMIRE. Friedman test and Wilcoxon rank sum test were used for multiple comparisons of CAC values and the difference ratio among different ADMIRE groups using FBP as reference.

RESULTS

The median Agatston score (range) using FBP was 115 (0.1-3047) and significantly decreased with incremental ADMIRE levels 1-5: 96 (0.1-2813), 91 (0-2764), 87 (0-2699), 80 (0-2590), 70 (0-2440); all P < 0.001. In comparison with FBP Agatston, volume and mass scores significantly decreased with increasing ADMIRE levels 1-5 (P < 0.001): from -12% to -39%, from -14% to -41%, and from -13% to -40%, respectively. In four patients with low calcium burden, the use of ADMIRE 2 or higher resulted in the disappearance of calcium that was detectable using FBP or ADMIRE 1. The decrease of CAC in high-level ADMIRE resulted in a reassignment to a lower Agatston risk group in 27%.

CONCLUSIONS

ADMIRE causes a substantial reduction of the CAC scores measured by cardiac CT, which leads to an underestimation of cardiovascular risk scores in some patients.

Association between air pollution and coronary artery calcification within six metropolitan areas in the USA (the Multi-Ethnic Study of Atherosclerosis and Air Pollution): a longitudinal cohort study

BACKGROUND

Long-term exposure to fine particulate matter less than 2.5 μm in diameter (PM2.5) and traffic-related air pollutant concentrations are associated with cardiovascular risk. The disease process underlying these associations remains uncertain. We aim to assess association between long-term exposure to ambient air pollution and progression of coronary artery calcium and common carotid artery intima-media thickness.

METHODS

In this prospective 10-year cohort study, we repeatedly measured coronary artery calcium by CT in 6795 participants aged 45-84 years enrolled in the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) in six metropolitan areas in the USA. Repeated scans were done for nearly all participants between 2002 and 2005, for a subset of participants between 2005 and 2007, and for half of all participants between 2010 and 2012. Common carotid artery intima-media thickness was measured by ultrasound in all participants at baseline and in 2010-12 for 3459 participants. Residence-specific spatio-temporal pollution concentration models, incorporating community-specific measurements, agency monitoring data, and geographical predictors, estimated concentrations of PM2.5 and nitrogen oxides (NOX) between 1999 and 2012. The primary aim was to examine the association between both progression of coronary artery calcium and mean carotid artery intima-media thickness and long-term exposure to ambient air pollutant concentrations (PM2.5, NOX, and black carbon) between examinations and within the six metropolitan areas, adjusting for baseline age, sex, ethnicity, socioeconomic characteristics, cardiovascular risk factors, site, and CT scanner technology.

FINDINGS

In this population, coronary calcium increased on average by 24 Agatston units per year (SD 58), and intima-media thickness by 12 μm per year (10), before adjusting for risk factors or air pollutant exposures. Participant-specific pollutant concentrations averaged over the years 2000-10 ranged from 9.2-22.6 μg PM2.5/m(3) and 7.2-139.2 parts per billion (ppb) NOX. For each 5 μg PM2.5/m(3) increase, coronary calcium progressed by 4.1 Agatston units per year (95% CI 1.4-6.8) and for each 40 ppb NOX coronary calcium progressed by 4.8 Agatston units per year (0.9-8.7). Pollutant exposures were not associated with intima-media thickness change. The estimate for the effect of a 5 μg/m(3) higher long-term exposure to PM2.5 in intima-media thickness was -0.9 μm per year (95% CI -3.0 to 1.3). For 40 ppb higher NOX, the estimate was 0.2 μm per year (-1.9 to 2.4).

INTERPRETATION

Increased concentrations of PM2.5 and traffic-related air pollution within metropolitan areas, in ranges commonly encountered worldwide, are associated with progression in coronary calcification, consistent with acceleration of atherosclerosis. This study supports the case for global efforts of pollution reduction in prevention of cardiovascular diseases.

FUNDING

US Environmental Protection Agency and US National Institutes of Health.

Relationships between measures of adiposity with subclinical atherosclerosis in patients with type 2 diabetes

OBJECTIVE

Assess cross-sectional relationships between body mass index (BMI), waist circumference (WC), pericardial (PAT), visceral (VAT), and subcutaneous adipose tissue (SAT) volumes with calcified plaque (CP) in African Americans (AAs) and European Americans (EAs) with type 2 diabetes.

METHODS

Computed tomography measured PAT, VAT, SAT, and CP in coronary arteries (CAC), carotid arteries, and aorta. Generalized estimating equations models were fitted to test for associations between adiposity and CP, stratified by ethnicity while accounting for familial correlations.

RESULTS

AAs (N = 753) vs. EAs (N = 562) had significantly lower PAT and VAT, despite equal or higher BMI. In multivariable models adjusting for age, gender, education, HbA1c, statins, smoking, cardiovascular disease, hypertension, nephropathy, and C-reactive protein, PAT positively associated with presence of CAC in AAs (P < 0.001), not EAs (P = 0.68; ethnicity interaction P < 0.01). Inverse associations were detected between SAT and severity of aorta CP (P < 0.01) in AAs and between BMI, WC, and SAT with severity of aorta CP in all participants.

CONCLUSIONS

Ethnic- and gender-specific differences in BMI, WC, PAT, SAT, and VAT were present in AAs and EAs with diabetes. Only PAT was positively associated with CAC in AAs; paradoxical inverse associations were seen between several other adiposity measures and subclinical cardiovascular disease.

Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Risk Score in Young Adults Predicts Coronary Artery and Abdominal Aorta Calcium in Middle Age: The CARDIA Study

BACKGROUND

We explored whether, the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) coronary and abdominal risk scores measured at 18 to 30 years of age and changes in these scores would more strongly predict coronary artery calcium (CAC) and abdominal aortic calcium (AAC) assessed 25 years later, than scores measured 25 years later.

METHODS AND RESULTS

In the Coronary Artery Risk Development in Young Adults (CARDIA) study, 3008 participants had measurements of risk score components at 5-year intervals beginning at 18 to 30 years of age. CAC and AAC were assessed at 43 to 55 years of age. Odds ratios (ORs) for the presence and extent of CAC/AAC per/point higher score and c-statistics for predicting CAC/AAC were calculated. The prevalence of CAC was 28% and AAC was 53%. For each 1 point higher PDAY score, the odds of CAC were higher using baseline scores than year 25 scores (OR, 1.29; 95% confidence interval [CI], 1.25-1.33 versus OR, 1.12; 95% CI, 1.11-1.14). For AAC, ORs at years 0 and 25 were similar (OR, 1.29; 95% CI, 1.24-1.34 versus OR, 1.22; 95% CI, 1.19-1.26). C-statistic for CAC prediction was higher at year 0 than year 25 (0.731 versus 0.705) but similar at years 0 and 25 for AAC (0.665 versus 0.670). ORs for CAC were highest at baseline, and, for AAC, ORs were highest at year 10. Including change in PDAY scores with baseline scores improved prediction.

CONCLUSIONS

Atherosclerosis risk and change in risk assessed in young adulthood years before subclinical atherosclerosis imaging provide strong prediction of future subclinical atherosclerosis. CAC and AAC reflect chronic risk exposure in addition to risk measured at the time of study.

Implications of Coronary Artery Calcium Testing Among Statin Candidates According to American College of Cardiology/American Heart Association Cholesterol Management Guidelines: MESA (Multi-Ethnic Study of Atherosclerosis)

BACKGROUND

The American College of Cardiology (ACC)/American Heart Association (AHA) cholesterol management guidelines have significantly broadened the scope of candidates eligible for statin therapy.

OBJECTIVES

This study evaluated the implications of the absence of coronary artery calcium (CAC) in reclassifying patients from a risk stratum in which statins are recommended to one in which they are not.

METHODS

MESA (Multi-Ethnic Study of Atherosclerosis) is a longitudinal study of 6,814 men and women 45 to 84 years of age without clinical atherosclerotic cardiovascular disease (ASCVD) risk at enrollment. We excluded 1,100 participants (16%) on lipid-lowering medication, 87 (1.3%) without low-density lipoprotein levels, 26 (0.4%) with missing risk factors for calculation of 10-year risk of ASCVD, 633 (9%) >75 years of age, and 209 (3%) with low-density lipoprotein <70 mg/dl from the analysis.

RESULTS

The study population consisted of 4,758 participants (age 59 ± 9 years; 47% males). A total of 247 (5.2%) ASCVD and 155 (3.3%) hard coronary heart disease events occurred over a median (interquartile range) follow-up of 10.3 (9.7 to 10.8) years. The new ACC/AHA guidelines recommended 2,377 (50%) MESA participants for moderate- to high-intensity statins; the majority (77%) was eligible because of a 10-year estimated ASCVD risk ≥7.5%. Of those recommended statins, 41% had CAC = 0 and had 5.2 ASCVD events/1,000 person-years. Among 589 participants (12%) considered for moderate-intensity statin, 338 (57%) had a CAC = 0, with an ASCVD event rate of 1.5 per 1,000 person-years. Of participants eligible (recommended or considered) for statins, 44% (1,316 of 2,966) had CAC = 0 at baseline and an observed 10-year ASCVD event rate of 4.2 per 1,000 person-years.

CONCLUSIONS

Significant ASCVD risk heterogeneity exists among those eligible for statins according to the new guidelines. The absence of CAC reclassifies approximately one-half of candidates as not eligible for statin therapy.

Radiation dose reduction at coronary artery calcium scoring by using a low tube current technique and hybrid iterative reconstruction

PURPOSE

The aim of this study was to compare the accuracy of coronary artery calcium scoring (CACS) on cardiac computed tomographic images using hybrid iterative reconstruction (hIR) and a low tube current as well as on images acquired with a filtered back projection (FBP) algorithm and a normal tube current.

SUBJECTS AND METHODS

Patients (N = 77) with suspected coronary artery disease were subjected to 2 CACS evaluations based on their Agatston, volume, and mass scores. One CACS evaluation was performed on images obtained with a 364-mA tube current and reconstructed with FBP; the other was performed on images obtained with a 73-mA tube current and reconstructed with hIR at iDose4. All scans were performed with the prospective electrocardiogram-triggered method using a 256-slice computed tomographic scanner (Brilliance iCT; Philips). We assessed agreement between calcium scores obtained with FBP and with IR using the percentage difference and Bland-Altman analysis.

RESULTS

The effective radiation doses for CACS at 80 mA s with FBP and at 16 mA s with IR were 1.20 and 0.24 mSv, respectively (k = 0.014). The mean Agatston, volume, and mass scores at 80 mA s with FBP as well as at 16 mA s with IR were 390.7, 146.5, and 63.2 as well as 377.7, 142.5, and 62.2, respectively. The percentage difference between FBP and hIR for the Agatston, volume, and mass score was 20.7%, 20.7%, and 27.1%, respectively. Bland-Altman analysis showed that there was no systemic bias.

CONCLUSIONS

The radiation dose for CACS can be reduced at a low tube current and hIR without affecting the calcium score.

Scoring of coronary artery calcium scans: history, assumptions, current limitations, and future directions

Coronary artery calcium (CAC) scanning is a reliable, noninvasive technique for estimating overall coronary plaque burden and for identifying risk for future cardiac events. Arthur Agatston and Warren Janowitz published the first technique for scoring CAC scans in 1990. Given the lack of available data correlating CAC with burden of coronary atherosclerosis at that time, their scoring algorithm was remarkable, but somewhat arbitrary. Since then, a few other scoring techniques have been proposed for the measurement of CAC including the Volume score and Mass score. Yet despite new data, little in this field has changed in the last 15 years. The main focus of our paper is to review the implications of the current approach to scoring CAC scans in terms of correlation with the central disease - coronary atherosclerosis. We first discuss the methodology of each available scoring system, describing how each of these scores make important indirect assumptions in the way they account (or do not account) for calcium density, location of calcium, spatial distribution of calcium, and microcalcification/emerging calcium that might limit their predictive power. These assumptions require further study in well-designed, large event-driven studies. In general, all of these scores are adequate and are highly correlated with each other. Despite its age, the Agatston score remains the most extensively studied and widely accepted technique in both the clinical and research settings. After discussing CAC scoring in the era of contrast enhanced coronary CT angiography, we discuss suggested potential modifications to current CAC scanning protocols with respect to tube voltage, tube current, and slice thickness which may further improve the value of CAC scoring. We close with a focused discussion of the most important future directions in the field of CAC scoring.

Distribution of calcification in carotid endarterectomy tissues: Comparison of micro-computed tomography imaging with histology

Background:

Calcification in atherosclerotic plaques has been viewed as a marker of plaque stability, but whether calcification accumulates in specific anatomic sites in the carotid artery is unknown. We determined the burden and distribution of calcified plaque in carotid endarterectomy (CEA) tissues.

Methods:

A total of 22 CEA tissues were imaged with high-resolution micro-computed tomography (micro-CT). Total plaque burden and total calcium score using the Agatston method were quantified. The Agatston score (AS) was also normalized for tissue size. Plaque and calcium distribution were analyzed separately for three CEA regions: common segment (CS), bulb segment (BS), and internal/external segments (IES).

Results:

The average CEA tissue length was 40.83 (interquartile range [IQR] 33.31–42.41) mm with total plaque burden of 103.45 (IQR: 78.84–156.81) mm3 and total AS of 38.58 (IQR 11.59–89.97). Total plaque volume was 21.02 (IQR: 14.47–25.42) mm3 in the CS, 37.89 (22.59–48.32) mm3 in the BS, and 54.05 (36.87–74.52) mm3 in the IES. Of the 22 tissues, 15 had no calcium in the CS compared with three in the bulb and two in the IES. Normalized calcified plaque was most prevalent in the BS, the IES and was least prevalent in the CS. The overall correlation of calcification between histology sections and matched micro-CT images was 0.86 ( p<0.001).

Conclusions:

Calcified plaque is heterogeneously distributed in CEA tissues with most in the bulb and IES regions. The amount of calcification in micro-CT slices shows a high correlation with matched histology sections.

Associations between nonalcoholic fatty liver disease and subclinical atherosclerosis in middle-aged adults: the Coronary Artery Risk Development in Young Adults Study

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is an obesity-related condition associated with cardiovascular mortality. Yet, whether or not NAFLD is independently related to atherosclerosis is unclear. In a population-based cross-sectional sample of middle-aged adults free from liver or heart disease, we tested the hypothesis that NAFLD is associated with subclinical atherosclerosis (coronary artery (CAC) and abdominal aortic calcification (AAC)) independent of obesity.

METHODS

Participants from the Coronary Artery Risk Development in Young Adults study with CT quantification of liver fat, CAC and AAC were included (n = 2424). NAFLD was defined as liver attenuation ≤40 Hounsfield Units after exclusion of other causes of liver fat. CAC and AAC presence was defined as Agatston score >0.

RESULTS

Mean participant age was 50.1 ± 3.6 years, (42.7% men, 50.0% black) and BMI was 30.6 ± 7.2 kg/m(2). The prevalence of NAFLD, CAC, and AAC was 9.6%, 27.1%, and 51.4%. NAFLD participants had increased prevalence of CAC (37.9% vs. 26.0%, p < 0.001) and AAC (65.1% vs. 49.9%, p < 0.001). NAFLD remained associated with CAC (OR, 1.33; 95% CI, 1.001-1.82) and AAC (OR, 1.74; 95% CI, 1.29-2.35) after adjustment for demographics and health behaviors. However, these associations were attenuated after additional adjustment for visceral adipose tissue (CAC OR, 1.05; 95% CI, 0.74-1.48, AAC OR = 1.20; 95% CI, 0.86-1.67). There was no interaction by race or sex.

CONCLUSION

In contrast to prior research, these findings suggest that obesity attenuates the relationship between NAFLD and subclinical atherosclerosis. Further studies evaluating the role of NAFLD duration on atherosclerotic progression and cardiovascular events are needed.

Associations of cardiovascular disease risk factors and calcified atherosclerosis with aortoiliac bifurcation position: the MultiEthnic Study of Atherosclerosis

We investigated associations of cardiovascular disease (CVD) risk factors and calcified atherosclerosis with aortoiliac bifurcation position. The bifurcation position was determined by measuring the distance from the aortoiliac bifurcation to the L5-S1 disk space (or aortoiliac bifurcation distance [AIBD]), using computed tomography scans. The 1711 study participants (51% male) had a mean age of 62 ± 10 years and a mean AIBD of 26 ± 15 mm. In multivariable linear regression, older age, male gender, smoking, hypertension, larger aortic diameter, and smaller lumbar height were each independently associated with a smaller AIBD (more caudal bifurcation position). In contrast, diabetes, elevated triglycerides, and increased pulse pressure were independently associated with a larger AIBD (more cephalad bifurcation position). These findings suggest that age-related bifurcation descent is associated with CVD markers for aortic disease. Future studies should assess whether the bifurcation position is an independent prognosticator for CVD.

Impact of coronary artery calcium on coronary heart disease events in individuals at the extremes of traditional risk factor burden: the Multi-Ethnic Study of Atherosclerosis

AIMS

We sought to evaluate the impact of coronary artery calcium (CAC) in individuals at the extremes of risk factor (RF) burden.

METHODS AND RESULTS

6698 individuals from the Multi-Ethnic Study of Atherosclerosis (MESA) were followed for coronary heart disease (CHD) events over mean 7.1 ± 1 years. Annualized CHD event rates were compared among each RF category (0, 1, 2, or ≥3) after stratification by CAC score (0, 1-100, 101-300, and >300). The following traditional modifiable RFs were considered: cigarette smoking, LDL cholesterol ≥3.4 mmol/L, low HDL cholesterol, hypertension, and diabetes. There were 1067 subjects (16%) with 0 RFs, whereas 1205 (18%) had ≥3 RFs. Among individuals with 0 RFs, 68% had CAC 0, whereas 12 and 5% had CAC >100 and >300, respectively. Among individuals with ≥3 RFs, 35% had CAC 0, whereas 34 and 19% had CAC >100 and >300, respectively. Overall, 339 (5.1%) CHD events occurred. Individuals with 0 RFs and CAC >300 had an event rate 3.5 times higher than individuals with ≥3 RFs and CAC 0 (10.9/1000 vs. 3.1/1000 person-years). Similar results were seen across categories of Framingham risk score.

CONCLUSION

Among individuals at the extremes of RF burden, the distribution of CAC is heterogeneous. The presence of a high CAC burden, even among individuals without RFs, is associated with an elevated event rate, whereas the absence of CAC, even among those with many RF, is associated with a low event rate. Coronary artery calcium has the potential to further risk stratify asymptomatic individuals at the extremes of RF burden.

Asymptomatic subjects with zero coronary calcium score: coronary CT angiographic features of plaques in event-prone patients

The aims of this study were: (a) to assess clinical predictors and coronary computed tomography angiography (CCTA) characteristics of noncalcified coronary plaques (NCP) in subjects who had cardiac events despite a zero coronary artery calcium score (CACS), and (b) to describe computed tomography (CT) plaque characteristics in subjects with cardiac events. A total of 7,961 subjects with zero CACS were evaluated; 6,531 subjects underwent CCTA as part of a health check-up. Those who had zero CACS were included in our mid-term follow-up study. Cardiac events included cardiac death, acute coronary syndrome or revascularization with stable angina. More than one NCP was identified in 441 subjects with zero CACS, including 48 subjects with obstructive coronary artery disease (CAD) caused by NCPs. Age, male gender, hypertension, diabetes and low density lipoprotein were independent predictors of obstructive CAD. Among subjects with obstructive CAD, young adults were classified into low (79.2 %) or moderate (72.9 %) risk groups by the National Centers for Environmental Prediction III guidelines. Approximately 0.2 % of subjects had cardiac events during our follow-up period. All patients with cardiac events had NCPs with significantly lower mean CT numbers, higher remodeling indexes and worse degree of stenosis. In asymptomatic subjects with zero CACS, NCP was associated with cardiac events. CCTA might be useful for risk stratification among select populations with CAD and zero CACS who have certain plaque characteristics associated with cardiac events.