Coronary Artery Calcium Scanning Research Articles

False-Negative Low Tube Voltage Coronary CT Angiography: High Intravascular Attenuation at Coronary CT Angiography Can Mask Calcified Plaques.

To determine the impact of low tube voltage coronary CT angiography on detection of subclinical atherosclerosis. Retrospective sampling of an emergency department coronary CT angiography registry was performed. All patients in the registry underwent a noncontrast coronary artery calcium (CAC) scoring scan at 120 kV before coronary CT angiography. The study sample (n = 264) constituted patients with subclinical atherosclerosis (Coronary Artery Disease Reporting and Data System™ [CAD-RADS] 1 or 2) randomly mixed one-to-one with patients without atherosclerosis (CAD-RADS 0). The patients with coronary CT angiography performed at 70-90 kV were considered the low tube voltage group (n = 159) and patients with coronary CT angiography performed at 100-120 kV were considered the standard tube voltage group (n = 105). The number of coronary plaques and overall CAD-RADS classification (per patient) were evaluated twice: initially, by reading coronary CT angiography alone, and then, by coronary CT angiography in combination with a CAC scan. Considering the combined reading (CT angiography plus CAC scan) as the reference standard, the performance of coronary CT angiography alone was assessed for plaque detection and appropriate CAD-RADS (per patient) classification. The comparisons were made between the low tube voltage and standard tube voltage groups by using a Fisher exact test and χ2 test for proportions and a Mann-Whitney test and Kruskal-Wallis test for means. In total, 455 plaques were identified in 118 patients (70 of 159 patients in the low tube voltage group; 48 of 105 in the standard tube voltage group). When reading coronary CT angiographic images alone, 97 of 455 (21%) plaques were missed that led to an incorrect CAD-RADS classification in 16 of 264 (6%) studies (interpreted as CAD-RADS 0 instead of CAD-RADS 1 or 2). Missed plaques were significantly more frequent in the low tube voltage group versus the standard tube voltage group (41% [85 of 206] vs 5% [12 of 249], respectively; P < .001). Incorrect CAD-RADS classification was also seen more commonly in the low tube voltage group (8.8% [14 of 159] vs 2% [two of 105]; P = .01), typically at low plaque burden (median CAC score, 1; range, 1-4). Calcified plaques that appeared isodense to luminal contrast material attenuation were seen more frequently in the low tube voltage group compared with the standard tube voltage group (20% [32 of 159] vs 7.6% [eight of 105], respectively; P = .005). Coronary artery plaques may be missed at low tube voltage coronary CT angiographic examination performed without a concomitant CAC scan.© RSNA, 2019Supplemental material is available for this article.See also the commentary by Truong in this issue.

The association between progression of coronary artery calcium and colorectal adenoma: A retrospective follow-up study of asymptomatic Koreans.

The potential relationship between coronary artery calcium (CAC) and colorectal adenoma has been widely indicated. This study aimed to investigate the relationship between the risk of colorectal adenoma and CAC progression in asymptomatic Korean adults who underwent serial assessments by colonoscopy and CAC scan.A total of 754 asymptomatic participants, who had undergone serial CAC scans and colonoscopies for screening, were enrolled. Changes in CAC were assessed according to the absolute change between baseline and follow-up results. CAC progression was defined using Multi-Ethnic Study of Atherosclerosis method. Risk for adenoma at follow-up colonoscopy was determined using hazard ratio (HR) by Cox regression. The area under the receiver operating characteristic (ROC) curve was measured.The mean follow-up duration was 3.4 ± 2.5 years. CAC progression was found in 215 participants (28.5%). Participants with adenoma at index colonoscopy showed a higher rate of CAC progression than those without (38.8% vs 23.6%, P < .01). In participants with adenoma at index colonoscopy, CAC progression significantly increased the cumulative risk for adenoma at follow-up colonoscopy (HR = 1.48, 95% confidence interval [CI] 1.06-2.06, log-rank P = .021). In multivariate analysis, male sex (HR = 2.57, 95% CI 1.22-5.42, P = .013), ≥3 adenomas at index colonoscopy (HR = 2.60, 95% CI 1.16-5.85, P = .021), and CAC progression (HR = 2.74, 95% CI 1.48-5.08, P = .001) increased the risk of adenoma at follow-up colonoscopy. In participants without adenoma at index colonoscopy, neither baseline CAC presence nor CAC progression increased the risk of adenoma at follow-up colonoscopy. The interaction between CAC progression and adenoma at index colonoscopy was significant in multivariable model (P = .005). In the ROC analysis, AUC of CAC progression for adenoma at follow-up colonoscopy was 0.625 (95% CI 0.567-0.684, P < .001) in participants with adenoma at index colonoscopy.Participants with CAC progression, who are at high risk of coronary atherosclerosis, may need to be considered for follow-up evaluation of colorectal adenoma, especially those with adenoma at index colonoscopy.

Coronary Artery Calcium Scoring in 2019: Past, Present, and Future

In this review, we sought to present a clinically relevant history of coronary artery calcium (CAC) scoring from its initial introduction, to its more recent widespread adoption and guideline endorsement, to future directions of cutting-edge CAC research. Since prior exhaustive reviews on CAC scoring, the introduction of the Pooled Cohort Equations (PCEs) for the assessment of atherosclerotic cardiovascular disease (ASCVD) risk has been formative in reframing how clinicians discuss risk and prevention with their patients. However, given weaknesses in the performance of the PCEs, additional risk markers have been tested with none being equal to CAC scoring with its ability to reclassify risk. The use of CAC = 0 as a negative risk factor has proven reliable in diverse populations and has led to increased adoption of CAC scoring by clinical practice guidelines. Newer data explores how CAC scoring can be employed for the quantification of risk in different diseases including modeling the competing risks of ASCVD vs. cancer, how CAC can reclassify risk even on non-ECG gated chest computed tomography, and how the algorithm for scoring a CAC scan can be improved in the future. CAC scoring is a powerful adjunct to the PCEs in further characterizing risk, particularly in borderline to intermediate-risk populations. Newer studies suggest that CAC scoring can be adapted to non-ECG gated chest CTs and that newer CAC scores, which take into consideration the number of vessels, the diffusivity of disease, and important gender-specific interactions, can improve on the traditional Agatston method. Future research will continue to explore these newer areas as well as provide models for forecasting the lifetime risks of ASCVD vs. cancer based on age and sex-specific CAC scores.

Validation of the Coronary Artery Calcium Data and Reporting System (CAC-DRS): Dual importance of CAC score and CAC distribution from the Coronary Artery Calcium (CAC) consortium

BackgroundThe Coronary Artery Calcium Data and Reporting System (CAC-DRS), which takes into account the Agatston score category (A) and the number of calcified vessels (N) has not yet been validated in terms of its prognostic significance. MethodsWe included 54,678 patients from the CAC Consortium, a large retrospective clinical cohort of asymptomatic individuals free of baseline cardiovascular disease (CVD). CAC-DRS groups were derived from routine, cardiac-gated CAC scans. Cox proportional hazards regression models, adjusted for traditional CVD risk factors, were used to assess the association between CAC-DRS groups and CHD, CVD, and all-cause mortality. CAC-DRS was then compared to CAC score groups and regional CAC distribution using area under the curve (AUC) analysis. ResultsThe study population had a mean age of 54.2 ± 10.7, 34.4% female, and mean ASCVD score 7.3% ± 9.0. Over a mean follow-up of 12 ± 4 years, a total of 2,469 deaths (including 398 CHD deaths and 762 CVD deaths) were recorded. There was a graded risk for CHD, CVD and all-cause mortality with increasing CAC-DRS groups ranging from an all-cause mortality rate of 1.2 per 1,000 person-years for A0 to 15.4 per 1,000 person-years for A3/N4. In multivariable-adjusted models, those with CAC-DRS A3/N4 had significantly higher risk for CHD mortality (HR 5.9 (95% CI 3.6–9.9), CVD mortality (HR4.0 (95% CI 2.8–5.7), and all-cause mortality a (HR 2.5 (95% CI 2.1–3.0) compared to CAC-DRS A0. CAC-DRS had higher AUC than CAC score groups (0.762 vs 0.754, P < 0.001) and CAC distribution (0.762 vs 0.748, P < 0.001). ConclusionThe CAC-DRS system, combining the Agatston score and the number of vessels with CAC provides better stratification of risk for CHD, CVD, and all-cause death than the Agatston score alone. These prognostic data strongly support new SCCT guidelines recommending the use CAC-DRS scoring.

Coronary artery calcium scoring in low risk patients with family history of coronary heart disease: Validation of the SCCT guideline approach in the coronary artery calcium consortium

BackgroundThe Society of Cardiovascular Computed Tomography (SCCT) recommends consideration of coronary artery calcium (CAC) scoring among individuals with a family history (FH) of coronary heart disease (CHD) and atherosclerotic cardiovascular disease (ASCVD) risk <5%. No dedicated study has examined the prognostic significance of CAC scoring among this population. MethodsThe CAC Consortium is a multi-center observational cohort study from four clinical centers linked to long-term follow-up for cause-specific mortality. All CAC scans were physician referred and performed in patients without a history of CHD. Our analysis includes 14,169 patients with ASCVD scores <5% and self-reported FH of CHD. ResultsThis cohort had a mean age of 48.1 (SD 7.4), was 91.3% white, 47.4% female, had an average ASCVD score of 2.3% (SD 1.3), and 59.4% had a CAC = 0. The event rate for all-cause mortality was 1.2 per 1000 person-years, 0.3 per 1000 person-years for CVD-specific mortality, and 0.2 per 1000 person-years for CHD-specific mortality. In multivariable Cox proportional hazard models, those with CAC>100 had a 2.2 (95% CI 1.5–3.3) higher risk of all-cause mortality, 4.3 (95% CI 1.9–9.5) times higher risk of CVD-specific mortality, and a 10.4 (95% CI 3.2–33.7) times higher risk of CHD-specific mortality compared to individuals with CAC = 0. The NNS to detect CAC >100 in this sample was 9. ConclusionIn otherwise low risk patients with FH of CHD, CAC>100 were associated with increased risk of all-cause and CHD mortality with event rates in a range that may benefit with preventive pharmacotherapy. These data strongly support new SCCT recommendations regarding testing of patients with a family history of CHD.

SCREENING FOR CORONARY ARTERY CALCIUM IN ASYMPTOMATIC ADULTS BASED ON THE 10-YEAR FRAMINGHAM RISK SCORE IN THE SOCIETY FOR HEART ATTACK PREVENTION AND ERADICATION (SHAPE) COHORT

Coronary artery calcium (CAC) scans are increasingly used in low & intermediate-risk asymptomatic patients for detecting subclinical coronary heart disease. CAC scans can further reclassify patients with clinical risk factors into subcategories of low, intermediate and high. Identifying at-risk

UTILITY OF PATIENT RISK QUESTIONNAIRE TO IDENTIFY CANDIDATES FOR CORONARY CALCIUM SCREENING

Coronary artery calcium (CAC) scanning is a useful tool to assess atherosclerotic cardiovascular disease (ASCVD) risk. Guidelines for CAC scanning have focused on intermediate risk patients for ASCVD. We examined the utility of a patient risk questionnaire (PRQ) including non-traditional risk

A Simplified Approach to Reducing Cardiovascular Risk

Cardiovascular disease remains the number one cause of morbidity and mortality in the United States, despite major advances in our understanding of its pathogenesis and prevention. One reason for this continued epidemic is the poor adherence to treatment guidelines by caregivers and the lack of understanding by patients relative to its reversibility with treatment. Current guidelines are complex and often contradictory; there are at least 21 organizations publishing guidelines. This article proposes a simplified approach that is based on the low-density lipoprotein (LDL) hypothesis stating that the lower the LDL cholesterol (LDL-C), the less the cardiovascular disease. This goal focuses on obtaining a plasma LDL-C <50 mg/dL. A positive coronary artery calcium scan in conjunction with an intermediate online cardiovascular risk score will identify individuals with substantial cardiovascular disease risk. With lifestyle improvements (including a low cholesterol diet) and low-dose hypolipemic generic oral medications, this LDL-C concentration is readily achievable in the majority of asymptomatic patients at risk for atherosclerosis. Controlling the cardiovascular epidemic will require participation of both the patient and the physician caregiver. By simplifying the therapeutic regimen, patient compliance will increase, and an important reduction in cardiovascular morbidity and mortality will follow.

Association of All-Cause and Cardiovascular Mortality With High Levels of Physical Activity and Concurrent Coronary Artery Calcification

Few data are available to guide clinical recommendations for individuals with high levels of physical activity in the presence of clinically significant coronary artery calcification (CAC). To assess the association among high levels of physical activity, prevalent CAC, and subsequent mortality risk. The Cooper Center Longitudinal Study is a prospective observational study of patients from the Cooper Clinic, a preventive medicine facility. The present study included participants seen from January 13, 1998, through December 30, 2013, with mortality follow-up through December 31, 2014. A total of 21 758 generally healthy men without prevalent cardiovascular disease (CVD) were included if they reported their physical activity level and underwent CAC scanning. Data were analyzed from September 26, 2017, through May 2, 2018. Self-reported physical activity was categorized into at least 3000 (n = 1561), 1500 to 2999 (n = 3750), and less than 1500 (n = 16 447) metabolic equivalent of task (MET)-minutes/week (min/wk). The CAC scores were categorized into at least 100 (n = 5314) and less than 100 (n = 16 444) Agatston units (AU). All-cause and CVD mortality collected from the National Death Index Plus. Among the 21 758 male participants, baseline mean (SD) age was 51.7 (8.4) years. Men with at least 3000 MET-min/wk were more likely to have prevalent CAC of at least 100 AU (relative risk, 1.11; 95% CI, 1.03-1.20) compared with those accumulating less physical activity. In the group with physical activity of at least 3000 MET-min/wk and CAC of at least 100 AU, mean (SD) CAC level was 807 (1120) AU. After a mean (SD) follow-up of 10.4 (4.3) years, 759 all-cause and 180 CVD deaths occurred, including 40 all-cause and 10 CVD deaths among those with physical activity of at least 3000 MET-min/wk. Men with CAC of less than 100 AU and physical activity of at least 3000 MET-min/wk were about half as likely to die compared with men with less than 1500 MET-min/wk (hazard ratio [HR], 0.52; 95% CI, 0.29-0.91). In the group with CAC of at least 100 AU, men with at least 3000 MET-min/wk did not have a significant increase in all-cause mortality (HR, 0.77; 95% CI, 0.52-1.15) when compared with men with physical activity of less than 1500 MET-min/wk. In the least active men, those with CAC of at least 100 AU were twice as likely to die of CVD compared with those with CAC of less than 100 AU (HR, 1.93; 95% CI, 1.34-2.78). This study suggests there is evidence that high levels of physical activity (≥3000 MET-min/wk) are associated with prevalent CAC but are not associated with increased all-cause or CVD mortality after a decade of follow-up, even in the presence of clinically significant CAC levels.

Utility of novel serum biomarkers to predict subclinical atherosclerosis: A sub-analysis of the EISNER study

Background and aimsCertain novel biomarkers may predict atherosclerotic cardiovascular disease (ASCVD) events; however, data on their relationship to coronary atherosclerosis and its progression as measured by coronary artery calcium (CAC) scanning is lacking. We evaluated the association between novel biomarkers and presence or progression of CAC. MethodsThe EISNER study was a prospective trial of patients without known ASCVD. Data on CAC and several biomarkers (hs-CRP, LTβR, osteopontin [OPN], RAGE, TNFR1α and TROY) were available at baseline and 4-year follow-up. Biomarkers were standardized and summed for a composite score. CAC progression was defined by the square-root (CACSQRT) method and rapid (top decile) progression. Adjusted regression models created a final prediction model for baseline CAC and CAC progression. Results1207 subjects (mean age 58.4 ± 8 years, 53% male) were evaluated; 621 had a baseline CAC >0, in whom 323 progressed by CACSQRT, and 121 rapidly progressed. Baseline CAC was associated only with OPN (p = 0.03), TROY (p = 0.0058) and TNFR1α (p = 0.0039) in unadjusted analyses. In adjusted analyses, only OPN was independently related to CAC progression using CACSQRT (p = 0.04). ConclusionsOPN identifies progression of atherosclerosis in persons free of ASCVD at baseline and may be a useful predictive tool to guide ASCVD prevention management.

Coronary Artery Dose-Volume Parameters Predict Risk of Calcification After Radiation Therapy.

BACKGROUNDRadiation exposure increases the risk of coronary artery disease (CAD). We explored the association of CAD with coronary artery dose-volume parameters in patients treated with 3D-planned radiation therapy (RT).METHODSPatients who received thoracic RT and were evaluated by cardiac computed tomography ≥ 1 year later were included. Demographic data and cardiac risk factors were retrospectively collected. Dosimetric data (mean heart dose, dmax, dmean, V50 - V5) were collected for the whole heart and for each coronary artery. A coronary artery calcium (CAC) Agatston score was calculated on a per-coronary basis and as a total score. Multivariable generalized linear mixed models were generated. The predicted probabilities were used for receiver operating characteristic analyses.RESULTSTwenty patients with a median age of 53 years at the time of RT were included. Nine patients (45%) had ≥ 3/6 conventional cardiac risk factors. Patients received RT for breast cancer (10, 50%), lung cancer (6, 30%), or lymphoma/myeloma (4, 20%) with a median dose of 60 Gy. CAC scans were performed a median of 32 months after RT. CAC score was significantly associated with radiation dose and presence of diabetes. In a multivariable model adjusted for diabetes, segmental coronary artery dosimetric parameters (dmax, dmean, V50, V40 V30, V20, V10, and V5) were significantly associated with CAC score > 0. V50 had the highest area under the ROC curve (0.89, 95% confidence interval, 0.80-0.97).CONCLUSIONSCoronary artery radiation exposure is strongly correlated with subsequent segmental CAC score. Coronary calcification may occur soon after RT and in individuals with conventional cardiac risk factors.

Age- and gender-adjusted percentiles for number of calcified plaques in coronary artery calcium scanning

BackgroundAge- and gender-adjusted percentiles of coronary artery calcium (CAC) score are commonly reported to compare a patient's coronary atherosclerosis burden to that of others of the same age and gender. The number of calcified plaques (numCP) detected on CAC scanning, a measure of plaque diffusivity, is associated with increased cardiovascular risk and, in the intermediate CAC range, adds to the CAC score in predicting mortality. This study aims to develop adjusted percentiles for numCP to provide a better context for understanding CAC scan findings. Methods and resultsUsing nonparametric modeling techniques, the distribution of numCP was analyzed in 70,320 consecutive, asymptomatic patients without prior clinically-diagnosed cardiovascular disease who were part of the Coronary Artery Calcium Consortium and supplemented by additional patients referred for clinical CAC scanning in a single center between 1998 and 2016. Nomograms for age-adjusted numCP percentiles for each gender were generated using quantile regression. The prevalence and average number of calcified coronary plaque were found to be higher in men than women. Distribution of numCP in women was found to closely mirror that of men approximately a decade younger. NumCP increased consistently across age groups in both men and women for each quantile category. ConclusionsA nomogram for age and gender-adjusted percentiles for the numCP on CAC scans has been developed in a large population of asymptomatic patients studied across multiple centers. This numCP nomogram may provide an additional tool for refining physician recommendations regarding treatment and expressing to patients how their CAC findings relate to others of similar age and gender. The numCP percentiles may also provide a meaningful way to evaluate and report the rate of progression of CAC on serial studies.

Reduced radiation dose with model based iterative reconstruction coronary artery calcium scoring

Assessing coronary artery calcium (CAC) is a valuable tool for individualizing cardiac risk assessment. In CAC scanning, this technical report assesses the use of a true model-based iterative reconstruction algorithm using forward projected model-based iterative reconstruction (“FIRST”) and assess whether FIRST allows for reduced radiation dose CAC scanning on 320-detector row computed tomography (320-CT). Here, 100 consecutive patients prospectively underwent reduced and standard dose scans. For the patients (59 ± 9 years, 61% male) stratified by Agatston categories 0, 1–10, 11–100, 101–400,> 400, agreement between reduced dose with FIRST versus standard dose with FBP was excellent at 81% (95% CI: 73–88%) with kappa 0.74 (95% CI: 0.64–0.85). Median radiation exposure was 75% lower for reduced (0.35 mSv) versus standard dose (1.37 mSv) scans. In conclusion, agreement was excellent for reduced dose with FIRST and standard dose with FBP in 320-detector row CT CAC imaging in well-established categories of cardiovascular risk. These methods make it possible to reduce radiation exposure by 75%.

Serum Uric Acid Is Independently Associated with Coronary Calcification in an Asymptomatic Population

Detecting early-stage atherosclerosis is an important step towards cardiovascular disease prevention. Coronary artery calcium (CAC) score is a sensitive and non-invasive tool for detecting coronary atherosclerosis. Higher serum uric acid (SUA) levels are known to be associated with cardiovascular diseases. However, there is inconsistency regarding the independence of the association. The aim of our study was to assess the association of CAC and SUA in an asymptomatic population. CAC scans of 281 participants were analyzed in a voluntary screening program. A health questionnaire, physical examination, and laboratory tests were also performed. Participants with a history of cardiovascular disease were excluded from the analysis. 36.3% (n = 102) of the participants had no detectable CAC and 13.9% (n = 39) had a CAC score of > 300. SUA showed positive correlation with CAC score (0.175, p < 0.01). SUA was independently associated with Ca score > 300 (OR 5.17, p = 0.01) after the effects of conventional risk factors were eliminated.

Agatston score of the descending aorta is independently associated with coronary events in a low-risk population

ObjectivesA standard coronary artery calcium scan includes part of the aorta. This additional information is often not included in routine analyses. We aimed to determine the feasibility of assessing the...

Radiation exposure and coronary artery calcium scans in the society for heart attack prevention and eradication cohort.

Coronary artery calcium (CAC) scoring is used in asymptomatic patients to improve their clinically predicted risk for future cardiovascular events. Current CT protocols seek to reduce radiation exposure without diminishing image quality. Reported radiation exposure remains widely variable (0.8-5mSv) depending on the type of protocol. In this study, we report the radiation exposure of CAC scoring from the Society for Heart Attack Prevention and Eradication (SHAPE) early detection program cohort sites, which spanned multiple centers using 64-MDCT (multi-detector computed tomography) scanners. We reviewed radiation exposure in milliSieverts (mSv) for 82,214 participants from the SHAPE early detection program cohort who underwent CAC scoring. This occurred over a 2.5-year period (2012-2014) divided among 33 sites in 7 countries with four different types 64-MDCT scanners. The effective radiation dose was reported as mSv. Mean radiation dosing amongst all 82,214 participants was 1.03mSv, a median dose of 0.94mSv. The mean radiation dose ranged from 0.76 to 1.31mSv across the 33 sites involved with the SHAPE program cohort. Subgroup analysis by age, gender or body mass index (BMI) less than 30kg/m2 showed no variability. Radiation dose in patients with BMI > 30kg/m2 were significantly greater than other subgroups (µ = 1.96mSv, p < 0.001). The use of 64-MDCT scanners and protocols provide the effective radiation dose for CAC scoring, which is approximately 1mSv. This is consistently lower than previously reported for CAC scanning, regardless of scanner type, age or gender. In contrast, a greater BMI influenced mean radiation doses.

The Synergistic Use of Coronary Artery Calcium Imaging and Noninvasive Myocardial Perfusion Imaging for Detecting Subclinical Atherosclerosis and Myocardial Ischemia

This review aims to assess the synergistic use of coronary artery calcium (CAC) scanning and stress-rest SPECT myocardial perfusion imaging (MPI) for the workup of patients with suspected coronary artery disease (CAD). The CAC score bears a proportional relationship to both the frequency of obstructive CAD and inducible ischemia. Consequently, the test can be used to improve the Bayesian assessment of pre-test CAD likelihood and assist in triaging patients for stress testing. The CAC score and MPI findings are synergistic for predicting cardiac risk, which increases for patients with abnormal MPI studies who also have CAC abnormality. CAC scanning also improves the diagnostic sensitivity of SPECT-MPI by identifying normal SPECT-MPI patients with subclinical atherosclerosis. Finally, CAC scanning helps improve the interpretation of borderline SPECT-MPI scan abnormalities. Combined, these findings indicate a clear benefit for incorporating CAC scanning into the diagnostic workup of patients who are candidates for the evaluation of chest pain symptoms by SPECT-MPI.

Long-term prognostic value of coronary artery calcium scanning, coronary computed tomographic angiography and stress myocardial perfusion imaging in patients with suspected coronary artery disease

BackgroundWe compared the long-term prognostic value of coronary artery calcium (CAC) scanning, coronary computed tomographic angiography (CCTA), and stress single-photon emission computed tomography myocardial perfusion imaging (MPI) in patients with suspected coronary artery disease (CAD). Methods and ResultsA total of 164 patients were studied. CAC score was measured according to the Agatston method and patients were categorized into 3 groups (0, 1-300, and >300). The following events were recorded: cardiac death, nonfatal infarction, and unstable angina requiring revascularization. Follow-up was 95% complete during a mean period of 82 ± 34 months. During follow-up, 22 events occurred (14% cumulative event rate). Event-free survival decreased with worsening of CAC score category (P < .001) and it was worse (P < .001) in patients with significant CAD (≥50% stenosis) and in those with stress-induced ischemia (summed difference score >2). At multivariable analysis, CAC (P = .001) and ischemia (P = .012) were independent predictors of events. MPI data added prognostic information to a model including clinical variables, CAC and CCTA findings, increasing the global Chi-square from 36.2 to 41.9 (P = .013). The decision curve analyses in patients with CAC score >0 indicate that the prognostic model including MPI resulted in a higher net benefit across a wide range of decision threshold probabilities. ConclusionsCAC and MPI, but not CCTA, are independent predictors of cardiac events. Stress MPI appears to improve risk stratification over clinical variables, CAC scanning and CCTA findings.

Abstract P281: All-cause and Cardiovascular Mortality in Men With High Levels of Physical Activity and Coronary Artery Calcification

Introduction: Recent studies have suggested that extreme levels of physical activity (endurance athletes) are associated with subclinical atherosclerosis as well as increased mortality. The safety of continuing high levels of physical activity is uncertain once coronary artery calcification (CAC) is discovered. Hypothesis: We hypothesized that men performing &amp;ge3000 MET·minutes/week of physical activity would have greater all-cause and cardiovascular (CV) mortality compared to those with &amp;lt1500 or 1500-&amp;lt3000 MET·minutes/week of physical activity and that mortality risk would be greater in those with CAC&amp;ge100 compared to &amp;lt100 Agatston units. Methods: The cohort studied included 16,109 men without prevalent CV disease who reported physical activity levels and underwent EBT or MDCT scan. Physical activity was categorized into &amp;ge3000 (n=1,266), 1500-3000 (n=3,027), and &amp;lt1500 (n=11,816) MET·minutes/week. CAC scanning included EBT scans (1997-2007) or MDCT scans (2007-2013), and CAC score was categorized into &amp;ge100 (n=3,547) and &amp;lt100 (n=12,562) Agatston units. We fit separate proportional hazards regression models to follow-up times for all-cause and CV mortality. The models included all combinations of CAC and physical activity categories and were adjusted for baseline age, smoking, BMI, cholesterol, HDLc, and systolic blood pressure. Results: The average age of participants at baseline was 51.3±8.3 years. Men with the highest activity level had a lower BMI and higher HDLc. After an average follow-up of 8.9 years, there were 329 all-cause and 60 CV deaths, including 174 all-cause and 38 CV deaths in those with CAC&amp;ge100. The sample had 80% power to detect all-cause mortality hazard ratios &amp;ge 1.9 and 1.8 for physical activity &amp;ge3000 versus &amp;lt1500 in those with CAC&amp;lt100 and &amp;ge100, respectively. The corresponding minimum detectable CV mortality hazard ratios were 3.5 and 2.8. Comparing physical activity &amp;ge3000 to &amp;lt1500 in those with CAC&amp;ge100, the hazard ratios (95% CI) were 0.9 (0.5, 1.5) for all-cause mortality and 0.9 (0.3, 3.1) for CV mortality. Hazard ratios were similar when comparing physical activity &amp;ge3000 to 1500-&amp;lt3000 in those with CAC &amp;ge100. Finally, when comparing physical activity categories, there was no evidence that hazard ratios varied by CAC category, p&amp;gt0.7. Conclusions: This sample offers no evidence that levels of activity &amp;ge3000 MET·minutes/week are associated with increased all-cause or CV mortality compared to those with &amp;lt1500 or 1500- &amp;lt3000 MET·minutes/week, regardless of CAC level.

OSTEOPONTIN: A NEW FRONTIER IN BIOMARKERS FOR ASCVD PREDICTION

Certain novel biomarkers may predict atherosclerotic cardiovascular disease (ASCVD) events; however, data on their relationship to coronary atherosclerosis and its progression as measured by coronary artery calcium (CAC) scanning is lacking. We evaluated the association between novel biomarkers and