Left Main Coronary Artery Calcium and Diabetes Confer Very-High-Risk Equivalence in Coronary Artery Calcium >1,000

BACKGROUND

Although a coronary artery calcium (CAC) of ≥1,000 is a subclinical atherosclerosis threshold to consider combination lipid-lowering therapy, differentiating very high from high atherosclerotic cardiovascular disease (ASCVD) risk in this patient population is not well-defined.

OBJECTIVES

Among persons with a CAC of ≥1,000, the authors sought to identify risk factors equating with very high-risk ASCVD mortality rates.

METHODS

The authors studied 2,246 asymptomatic patients with a CAC of ≥1,000 from the CAC Consortium without a prior ASCVD event. Cox proportional hazards regression modelling was performed for ASCVD mortality during a median follow-up of 11.3 years. Crude ASCVD mortality rates were compared with those reported for secondary prevention trial patients classified as very high risk, defined by ≥2 major ASCVD events or 1 major event and ≥2 high-risk conditions (1.4 per 100 person-years).

RESULTS

The mean age was 66.6 years, 14% were female, and 10% were non-White. The median CAC score was 1,592 and 6% had severe left main (LM) CAC (vessel-specific CAC ≥300). Diabetes (HR: 2.04 [95% CI: 1.47-2.83]) and severe LM CAC (HR: 2.32 [95% CI: 1.51-3.55]) were associated with ASCVD mortality. The ASCVD mortality per 100 person-years for all patients was 0.8 (95% CI: 0.7-0.9), although higher rates were observed for diabetes (1.4 [95% CI: 0.8-1.9]), severe LM CAC (1.3 [95% CI: 0.6-2.0]), and both diabetes and severe LM CAC (7.1 [95% CI: 3.4-10.8]).

CONCLUSIONS

Among asymptomatic patients with a CAC of ≥1,000 without a prior index event, diabetes, and severe LM CAC define very high risk ASCVD, identifying individuals who may benefit from more intensive prevention therapies across several domains, including low-density lipoprotein-cholesterol lowering.

Thoracic Aortic Calcium Density and Area in Long-Term Atherosclerotic Cardiovascular Disease Risk Among Men Versus Women

BACKGROUND

The development of thoracic aortic calcium (TAC) temporally precedes coronary artery calcium more often in women versus men. Whether TAC density and area confer sex-specific differences in atherosclerotic cardiovascular disease (ASCVD) risk is unknown.

METHODS

We studied 5317 primary prevention patients who underwent coronary artery calcium scoring on noncontrast cardiac gated computed tomography with TAC >0. The Agatston TAC score (Agatston units), density (Hounsfield units), and area (mm2) were compared between men and women. Cox proportional hazards regression calculated adjusted hazard ratios for TAC density-area groups with ASCVD mortality, adjusting for traditional risk factors, coronary artery calcium, and TAC. Multinomial logistic regression calculated adjusted odds ratios for the association between traditional risk factors and TAC density-area groups.

RESULTS

The mean age was 60.7 years, 38% were women, and 163 ASCVD deaths occurred over a median of 11.7-year follow-up. Women had higher median TAC scores (97 versus 84 Agatston units; P=0.004), density (223 versus 210 Hounsfield units; P<0.001), and area (37 versus 32 mm2; P=0.006) compared with men. There was a stepwise higher incidence of ASCVD deaths across increasing TAC density-area groups in men though women with low TAC density relative to TAC area (3.6 per 1000 person-years) had survival probability commensurate with the high-density-high-area group (4.8 per 1000 person-years). Compared with low TAC density-area, low TAC density/high TAC area conferred a 3.75-fold higher risk of ASCVD mortality in women (adjusted hazard ratio, 3.75 [95% CI, 1.13-12.44]) but not in men (adjusted hazard ratio, 1.16 [95% CI, 0.48-2.84]). Risk factors most strongly associated with low TAC density/high TAC area differed in women (diabetes: adjusted odds ratio, 2.61 [95% CI, 1.34-5.07]) versus men (hypertension: adjusted odds ratio, 1.45 [95% CI, 1.11-1.90]).

CONCLUSIONS

TAC density-area phenotypes do not consistently associate with ASCVD mortality though low TAC density relative to area may be a marker of increased ASCVD risk in women.

Cardiovascular risk stratification among individuals with obesity: The Coronary Artery Calcium Consortium

OBJECTIVE

The effectiveness of coronary artery calcification (CAC) for risk stratification in obesity, in which imaging is often limited because of a reduced signal to noise ratio, has not been well studied.

METHODS

Data from 9334 participants (mean age: 53.3 ± 9.7 years; 67.9% men) with BMI ≥ 30 kg/m2 from the CAC Consortium, a retrospectively assembled cohort of individuals with no prior cardiovascular diseases (CVD), were used. The predictive value of CAC for all-cause and cause-specific mortality was evaluated using multivariable-adjusted Cox proportional hazards and competing-risks regression.

RESULTS

Mean BMI was 34.5 (SD 4.4) kg/m2 (22.7% Class II and 10.8% Class III obesity), and 5461 (58.5%) had CAC. Compared with CAC = 0, those with CAC = 1-99, 100-299, and ≥300 Agatston units had higher rates (per 1000 person-years) of all-cause (1.97 vs. 3.5 vs. 5.2 vs. 11.3), CVD (0.4 vs. 1.1 vs. 1.5 vs. 4.2), and coronary heart disease (CHD) mortality (0.2 vs. 0.6 vs. 0.6 vs. 2.5), respectively, after mean follow-up of 10.8 ± 3.0 years. After adjusting for traditional cardiovascular risk factors, CAC ≥ 300 was associated with significantly higher risk of all-cause (hazard ratio [HR]: 2.05; 95% CI: 1.49-2.82), CVD (subdistribution HR: 3.48; 95% CI: 1.81-6.70), and CHD mortality (subdistribution HR: 5.44; 95% CI: 2.02-14.66), compared with CAC = 0. When restricting the sample to individuals with BMI ≥ 35 kg/m2 , CAC ≥ 300 remained significantly associated with the highest risk.

CONCLUSIONS

Among individuals with obesity, including moderate-severe obesity, CAC strongly predicts all-cause, CVD, and CHD mortality and may serve as an effective cardiovascular risk stratification tool to prioritize the allocation of therapies for weight management.

Coronary Artery Calcium Dispersion and Cause-Specific Mortality

Coronary artery calcium (CAC) measures subclinical atherosclerosis and improves risk stratification. CAC characteristics-including vessel(s) involved, number of vessels, volume, and density-have been shown to differentially impact risk. We assessed how dispersion-either the number of calcified vessels or CAC phenotype (diffuse, normal, and concentrated)-impacted cause-specific mortality. The CAC Consortium is a retrospective cohort of 66,636 participants without coronary heart disease (CHD) who underwent CAC scoring. This study included patients with CAC >0 (n = 28,147). CAC area, CAC density, and CAC phenotypes (derived from the index of diffusion = 1 - [CAC in most concentrated vessel/total Agatston score]) were calculated. The associations between CAC characteristics and cause-specific mortality were assessed. The participant details included (n = 28,147): mean age 58.3 years, 25% female, 89.6% White, and 66% had 2+ calcified vessels. Diabetes, hypertension, and hyperlipidemia were predictors of multivessel involvement (p <0.001). After controlling for the overall CAC score, those with 4-vessel CAC involvement had more CAC area and less dense calcifications than those with 1-vessel. There was a graded increase in all-cause and cardiovascular disease (CVD)- and CHD-specific mortality as the number of calcified vessels increased. Among those with ≥2 vessels involved (n = 18,516), a diffuse phenotype was associated with a higher CVD-specific mortality and had a trend toward higher all-cause and CHD-specific mortality than a concentrated CAC phenotype. Diffuse CAC involvement was characterized by less dense calcification, more CAC area, multiple coronary vessel involvement, and presence of certain traditional risk factors. There is a graded increase in all-cause and CVD- and CHD-specific mortality with increasing CAC dispersion.

Discordance Between Coronary Artery Calcium Area and Density Predicts Long-Term Atherosclerotic Cardiovascular Disease Risk

BACKGROUND

Coronary artery calcium (CAC) is commonly quantified as the product of 2 generally correlated measures: plaque area and calcium density.

OBJECTIVES

The authors sought to determine whether discordance between calcium area and density has long-term prognostic importance in atherosclerotic cardiovascular disease (ASCVD) risk.

METHODS

The authors studied 10,373 primary prevention participants from the CAC Consortium with CAC >0. Based on their median values, calcium area and mean calcium density were divided into 4 mutually exclusive concordant/discordant groups. Cox proportional hazards regression assessed the association of calcium area/density groups with ASCVD mortality over a median of 11.7 years, adjusting for traditional risk factors and the Agatston CAC score.

RESULTS

The mean age was 56.7 years, and 24% were female. The prevalence of plaque discordance was 19% (9% low calcium area/high calcium density, 10% high calcium area/low calcium density). Female sex (odds ratio [OR]: 1.48 [95% CI: 1.27-1.74]) and body mass index (OR: 0.81 [95% CI: 0.76-0.87], per 5 kg/m2 higher) were significantly associated with high calcium density discordance, whereas diabetes (OR: 2.23 [95% CI: 1.85-3.19]) was most strongly associated with discordantly low calcium density. Compared to those with low calcium area/low calcium density, individuals with low calcium area/high calcium density had a 71% lower risk of ASCVD death (HR: 0.29 [95% CI: 0.09-0.95]).

CONCLUSIONS

For a given CAC score, high calcium density relative to plaque area confers lower long-term ASCVD risk, likely serving as an imaging marker of biological resilience for lesion vulnerability. Additional research is needed to define a robust definition of calcium area/density discordance for routine clinical risk prediction.

Coronary Artery Calcium for Risk Stratification of Sudden Cardiac Death: The Coronary Artery Calcium Consortium

BACKGROUND

Coronary artery calcium (CAC) is a marker of plaque burden. Whether CAC improves risk stratification for incident sudden cardiac death (SCD) beyond atherosclerotic cardiovascular disease (ASCVD) risk factors is unknown.

OBJECTIVES

SCD is a common initial manifestation of coronary heart disease (CHD); however, SCD risk prediction remains elusive.

METHODS

The authors studied 66,636 primary prevention patients from the CAC Consortium. Multivariable competing risks regression and C-statistics were used to assess the association between CAC and SCD, adjusting for demographics and traditional risk factors.

RESULTS

The mean age was 54.4 years, 33% were women, 11% were of non-White ethnicity, and 55% had CAC >0. A total of 211 SCD events (0.3%) were observed during a median follow-up of 10.6 years, 91% occurring among those with baseline CAC >0. Compared with CAC = 0, there was a stepwise higher risk (P trend < 0.001) in SCD for CAC 100 to 399 (subdistribution hazard ratio [SHR]: 2.8; 95% CI: 1.6-5.0), CAC 400 to 999 (SHR: 4.0; 95% CI: 2.2-7.3), and CAC >1,000 (SHR: 4.9; 95% CI: 2.6-9.9). CAC provided incremental improvements in the C-statistic for the prediction of SCD among individuals with a 10-year risk <7.5% (ΔC-statistic = +0.046; P = 0.02) and 7.5% to 20% (ΔC-statistic = +0.069; P = 0.003), which were larger when compared with persons with a 10-year risk >20% (ΔC-statistic = +0.01; P = 0.54).

CONCLUSIONS

Higher CAC burden strongly associates with incident SCD beyond traditional risk factors, particularly among primary prevention patients with low-intermediate risk. SCD risk stratification can be useful in the early stages of CHD through the measurement of CAC, identifying patients most likely to benefit from further downstream testing.

Mean Versus Peak Coronary Calcium Density on Non-Contrast CT: Calcium Scoring and ASCVD Risk Prediction

OBJECTIVES

This study sought to assess the relationship between mean vs peak calcified plaque density and their impact on calculating coronary artery calcium (CAC) scores and to compare the corresponding differential prediction of atherosclerotic cardiovascular disease (ASCVD) and coronary heart disease (CHD) mortality.

BACKGROUND

The Agatston CAC score is quantified per lesion as the product of plaque area and a 4-level categorical peak calcium density factor. However, mean calcium density may more accurately measure the heterogenous mixture of lipid-rich, fibrous, and calcified plaque reflective of ASCVD risk.

METHODS

We included 10,373 individuals from the CAC Consortium who had CAC >0 and per-vessel measurements of peak calcium density factor and mean calcium density. Area under the curve and continuous net reclassification improvement analyses were performed for CHD and ASCVD mortality to compare the predictive abilities of mean calcium density vs peak calcium density factor when calculating the Agatston CAC score.

RESULTS

Participants were on average 53.4 years of age, 24.4% were women, and the median CAC score was 68 Agatston units. The average values for mean calcium density and peak calcium density factor were 210 ± 50 HU and 3.1 ± 0.5, respectively. Individuals younger than 50 years of age and/or those with a total plaque area <100 mm2 had the largest differences between the peak and mean density measures. Among persons with CAC 1-99, the use of mean calcium density resulted in a larger improvement in ASCVD mortality net reclassification improvement (NRI) (NRI = 0.49; P < 0.001 vs. NRI = 0.18; P = 0.08) and CHD mortality discrimination (Δ area under the curve (AUC) = +0.169 vs +0.036; P < 0.001) compared with peak calcium density factor. Neither peak nor mean calcium density improved mortality prediction at CAC scores >100.

CONCLUSION

Mean and peak calcium density may differentially describe plaque composition early in the atherosclerotic process. Mean calcium density performs better than peak calcium density factor when combined with plaque area for ASCVD mortality prediction among persons with Agatston CAC 1-99.

Coronary artery calcium is associated with long-term mortality from lung cancer: Results from the Coronary Artery Calcium Consortium

BACKGROUND AND AIMS

Coronary artery calcium (CAC) scores have been shown to be associated with CVD and cancer mortality. The use of CAC scores for overall and lung cancer mortality risk prediction for patients in the Coronary Artery Calcium Consortium was analyzed.

METHODS

We included 55,943 patients aged 44-84 years without known heart disease from the CAC Consortium. There were 1,088 cancer deaths, among which 231 were lung cancer, identified by death certificates with a mean follow-up of 12.2 ± 3.9 years. Fine-and-Gray competing-risk regression was used for overall and lung cancer-specific mortality, accounting for the competing risk of CVD death and after adjustment for CVD risk factors. Subdistribution hazard ratios (SHR) were reported.

RESULTS

The mean age of all patients was 57.1 ± 8.6 years, 34.9% were women, and 89.6% were white. Overall, CAC was strongly associated with cancer mortality. Lung cancer mortality increased with increasing CAC scores, with rates per 1000-person years of 0.2 (95% CI: 0.1-0.3) for CAC = 0 and 0.8 (95% CI: 0.6-1.0) for CAC ≥400. Compared with CAC = 0, hazards were increased for those with CAC ≥400 for lung cancer mortality [SHR: 1.7 (95% CI: 1.2-2.6)], which was driven by women [SHR: 2.3 (95% CI: 1.1-4.8)], but not significantly increased for men. Risks were higher in those with positive smoking history [SHR: 2.2 (95% CI: 1.2-4.2)], with associations driven by women [SHR: 4.0 (95% CI: 1.4-11.5)].

CONCLUSIONS

CAC scores were associated with increased risks for lung cancer mortality, with strongest associations for current and former smokers, especially in women. Used in conjunction with other clinical variables, our data pinpoint a potential synergistic use of CAC scanning beyond CVD risk assessment for identification of high-risk lung cancer screening candidates.

Modeling the Recommended Age for Initiating Coronary Artery Calcium Testing Among At-Risk Young Adults

BACKGROUND

There are currently no recommendations guiding when best to perform coronary artery calcium (CAC) scanning among young adults to identify those susceptible for developing premature atherosclerosis.

OBJECTIVES

The purpose of this study was to determine the ideal age at which a first CAC scan has the highest utility according to atherosclerotic cardiovascular disease (ASCVD) risk factor profile.

METHODS

We included 22,346 CAC Consortium participants aged 30-50 years who underwent noncontrast computed tomography. Sex-specific equations were derived from multivariable logistic modeling to estimate the expected probability of CAC >0 according to age and the presence of ASCVD risk factors.

RESULTS

Participants were on average 43.5 years of age, 25% were women, and 34% had CAC >0, in whom the median CAC score was 20. Compared with individuals without risk factors, those with diabetes developed CAC 6.4 years earlier on average, whereas smoking, hypertension, dyslipidemia, and a family history of coronary heart disease were individually associated with developing CAC 3.3-4.3 years earlier. Using a testing yield of 25% for detecting CAC >0, the optimal age for a potential first scan would be at 36.8 years (95% CI: 35.5-38.4 years) in men and 50.3 years (95% CI: 48.7-52.1 years) in women with diabetes, and 42.3 years (95% CI: 41.0-43.9 years) in men and 57.6 years (95% CI: 56.0-59.5 years) in women without risk factors.

CONCLUSIONS

Our derived risk equations among health-seeking young adults enriched in ASCVD risk factors inform the expected prevalence of CAC >0 and can be used to determine an appropriate age to initiate clinical CAC testing to identify individuals most susceptible for early/premature atherosclerosis.

Prognostic significance of aortic valve calcium in relation to coronary artery calcification for long-term, cause-specific mortality: results from the CAC Consortium

AIMS

Aortic valve calcification (AVC) has been shown to be associated with increased cardiovascular disease (CVD) risk; however, whether this is independent of traditional risk factors and coronary artery calcification (CAC) remains unclear.

METHODS AND RESULTS

From the multicentre CAC Consortium database, 10 007 patients (mean 55.8±11.7 years, 64% male) with concomitant CAC and AVC scoring were included in the current analysis. AVC score was quantified using the Agatston score method and categorized as 0, 1-99, and ≥100. The endpoints were all-cause, CVD, and coronary heart disease (CHD) deaths. AVC (AVC>0) was observed in 1397 (14%) patients. During a median 7.8 (interquartile range: 4.7-10.6) years of study follow-up, 511 (5.1%) deaths occurred; 179 (35%) were CVD deaths, and 101 (19.8%) were CHD deaths. A significant interaction between CAC and AVC for mortality was observed (P<0.001). The incidence of mortality events increased with higher AVC; however, AVC ≥100 was not independently associated with all-cause, CVD, and CHD deaths after adjusting for CVD risk factors and CAC (P=0.192, 0.063, and 0.206, respectively). When further stratified by CAC<100 or ≥100, AVC ≥100 was an independent predictor of all-cause and CVD deaths only in patients with CAC <100, after adjusting for CVD risk factors and CAC [hazard ratio (HR): 1.93, 95% confidence interval (CI): 1.14-3.27; P=0.013 and HR: 2.71, 95% CI: 1.15-6.34; P=0.022, respectively].

CONCLUSION

Although the overall prognostic significance of AVC was attenuated after accounting for CAC, high AVC was independently associated with all-cause and CVD deaths in patients with low coronary atherosclerosis burden.

Implication of thoracic aortic calcification over coronary calcium score regarding the 2018 ACC/AHA Multisociety cholesterol guideline: results from the CAC Consortium

•

TAC in segments of the ascending and descending thoracic aorta can be assessed by routine CAC scanning.

•

TAC assessment with the threshold of 300 improved risk prediction and reclassification for CVD mortality when added to the ASCVD risk score and CAC.

•

TAC >300 may improve patient selection for those who would benefit more strongly from statin use, from intermediate ASCVD risk patients who should consider a statin (CAC=1-100), and those where a statin is not recommended (CAC=0).

Objective

TAC is associated with an increased atherosclerotic cardiovascular disease (ASCVD) risk, but it is unclear how to interpret thoracic aortic calcification (TAC) findings in conjunction with ASCVD risk and coronary artery calcium (CAC) score according to 2018 ACC/AHA Multisociety cholesterol guidelines. We evaluate the incremental value of thoracic aortic calcification TAC over CAC for predicting and reclassifying ASCVD mortality risk.

Method

The study included 30,630 asymptomatic individuals (mean age: 55 ± 8 years, male: 64%) from the CAC Consortium. TAC was categorized as TAC 0, 1-300, and >300. Patients were categorized as low (<5%), borderline (5–7.5%), intermediate (7.5–20%), or high (≥20%) 10-year ASCVD risk according to the Pooled Cohorts Equation. In the intermediate risk group, the utility of TAC beyond CAC for statin eligibility was assessed according to the guideline. CAC was categorized as CAC=0 (no statin), CAC 1-100 (favors statin), or CAC>100 (initiate stain).

Results

During the median 11.2 years (IQR 9.2–12.4) follow-up, 345 (1.1%) CVD deaths occurred. TAC>300 was associated with increased CVD mortality after adjusting for ASCVD risk and CAC (HR:4.72, 95% CI: 3.39–6.57, p<0.001). In borderline and intermediate risk groups, TAC improved discrimination when added to a model included ASCVD risk and CAC (C-statistic: 0.77 vs. 0.68 in borderline group; 0.67 vs. 0.63 in intermediate group, both p < 0.05). The addition of TAC over CAC improved risk reclassification in borderline, intermediate and high-risk groups (categorical net reclassification index: 0.40, 0.29, and 0.49, respectively, all p < 0.001). Of intermediate risk participants for whom consideration of CAC was recommended based on the guideline, TAC >300 was associated with an increased CVD mortality risk across each statin eligibility group (all p < 0.001, compared to TAC 0).

Conclusion

TAC was independently associated with CVD death. Among individuals with borderline or intermediate ASCVD risk, a TAC threshold of 300 may provide added prognostic and reclassification value beyond the current guideline-based approach.

Cardiovascular and All-Cause Mortality Risk by Coronary Artery Calcium Scores and Percentiles Among Older Adult Males and Females

BACKGROUND

Coronary calcium is a marker of coronary atherosclerosis and established predictor of cardiovascular risk in general populations; however, there are limited studies examining its prognostic value among older adults (≥75 years) and even less regarding its utility in older males compared with females. Accordingly, we sought to examine the prognostic significance of both absolute and percentile coronary calcium scores among older adults.

METHODS

The multicenter Coronary Artery Calcium Consortium consists of 66,636 asymptomatic patients without cardiovascular disease. Participants ages ≥75 were included in this study and stratified by sex. Multivariable Cox regression models were constructed to assess cardiovascular and all-cause mortality risk by Agatston coronary calcium scores and percentiles.

RESULTS

Among 2,474 asymptomatic patients (mean age 79 years, 10.4-year follow-up), prevalence of coronary artery calcium was 92%. For both sexes, but in females more so than males, higher coronary calcium score and percentiles were associated with increased cardiovascular and all-cause mortality risk. Those at the lowest coronary calcium categories (0-9 and <25 percentile) had significantly lower risk of cardiovascular and all-cause mortality relative to the rest of the population. Multivariable analyses of traditional cardiovascular risk factors and coronary artery calcium variables revealed that age and coronary calcium were the strongest independent predictors for adverse outcomes.

CONCLUSIONS

Both coronary artery calcium scores and percentiles are strongly predictive of cardiovascular and all-cause mortality among older adults, with greater risk-stratification among females than males. Both low coronary artery calcium scores 0-9 and <25th percentile define relatively low risk older adults.

Relation of Absence of Coronary Artery Calcium to Cardiovascular Disease Mortality Risk Among Individuals Meeting Criteria for Statin Therapy According to the 2018/2019 ACC/AHA Guidelines

The 2013 American College of Cardiology and the American Heart Association (ACC/AHA) guidelines resulted in broad recommendations for preventive statin therapy allocation in patients without known cardiovascular disease (CVD). Subsequent studies demonstrated significant heterogeneity of atherosclerotic cardiovascular disease risk across the primary prevention population. In 2018/2019, the guidelines were revised to optimize risk assessment and cholesterol management. We sought to evaluate the heterogeneity of risk in statin-recommended patients, using coronary artery calcium (CAC) according to 2018/2019 ACC/AHA guidelines in a primary prevention cohort. We evaluated 5,800 statin-naive patients aged 40 to 75 years without known coronary heart disease from the Cedars-Sinai Medical Center study cohort. All participants underwent clinical CAC scoring for risk stratification and were followed for all-cause and CVD-specific mortality. A total of 181 deaths occurred including 54 CVD deaths over a follow-up of 9.5 years. Overall, 1,939 participants would have been recommended statin therapy, 32% of whom had no detectable CAC. CAC = 0 participants had the lowest all-cause and CVD mortality rates in both statin-recommended and nonrecommended groups (0.2 and 0.4 CVD deaths per 1,000 person-years, respectively). Absence of CAC in statin-naive patients portends an approximately 12-fold lower CVD mortality (0.2% vs 2.4%) in those recommended for statin therapy compared with any CAC present. In conclusion, in a cohort of patients meeting the 2018/2019 ACC/AHA guidelines for statin therapy for primary prevention, there was a marked heterogeneity of CAC scores, with about one-third of the statin recommended population having no detectable CAC (CAC = 0) with a significantly lower CVD mortality compared with CAC>0.

Association between coronary artery calcium and cardiovascular disease as a supporting cause in cancer: The CAC consortium

BACKGROUND

Identifying cancer patients at high risk of CVD is important for targeting CVD prevention strategies and evaluating chemotherapy options in the context of cardiotoxicity. Coronary artery calcium (CAC), a strong marker of coronary atherosclerosis, is used clinically to enhance risk assessment, yet the value of CAC for assessing risk of CVD complications in cancer is poorly understood.

OBJECTIVE

In cases of cancer mortality, to determine the value of CAC for predicting risk of CVD as a supporting cause of death.

METHODS

The CAC Consortium is a multi-center cohort of 66,636 asymptomatic adults without CVD who underwent CAC scanning. During a follow-up of 12.5 years, 1129 patients died of cancer and were included in this analysis. The primary outcome was presence of CVD listed as a supporting cause of cancer mortality on official death certificates obtained from the National Death Index. Logistic regression models were used to assess the odds of CVD being listed as a supporting cause of death by CAC.

RESULTS

CVD was listed as a supporting cause of death in 306 (27%) cancer mortality cases. Baseline CAC was significantly higher in individuals with CVD-supported mortality. Odds ratios of having CVD-supported death increased by ASCVD risk score category [1.15 (0.81, 1.65) for 5-20% 10-year risk and 1.97 (1.36, 2.89) for ≥20% risk, in reference to <5% 10-year ASCVD risk] and CAC category [1.07 (0.73, 1.57) for CAC 1-99, 1.29 (0.87, 1.93) for CAC 100-399, and 2.14 (1.48, 3.09) for CAC ≥400 relative to CAC 0]. In the CAC ≥400 group, these associations remained significantly elevated after adjustment for traditional CVD risk factors [1.66 (1.08, 2.55)]. A sensitivity analysis using a more specific ASCVD-supported mortality outcome, defined as coronary heart disease, stroke, and peripheral artery disease, demonstrated that adjusted odds of ASCVD-supported cancer mortality were significantly elevated in the CAC ≥400 group relative to CAC 0 [3.09 (1.39, 7.38)].

CONCLUSIONS

In cancer mortality cases, high antecedent CAC predicted risk of having CVD as a supporting cause of death on official death certificates, independently of ASCVD risk score and CVD risk factors. CAC may be useful for identifying cancer patients at high CVD risk who might benefit from more intense preventive cardiovascular therapies.

Machine Learning Adds to Clinical and CAC Assessments in Predicting 10-Year CHD and CVD Deaths

OBJECTIVES

The aim of this study was to evaluate whether machine learning (ML) of noncontrast computed tomographic (CT) and clinical variables improves the prediction of atherosclerotic cardiovascular disease (ASCVD) and coronary heart disease (CHD) deaths compared with coronary artery calcium (CAC) Agatston scoring and clinical data.

BACKGROUND

The CAC score provides a measure of the global burden of coronary atherosclerosis, and its long-term prognostic utility has been consistently shown to have incremental value over clinical risk assessment. However, current approaches fail to integrate all available CT and clinical variables for comprehensive risk assessment.

METHODS

The study included data from 66,636 asymptomatic subjects (mean age 54 ± 11 years, 67% men) without established ASCVD undergoing CAC scanning and followed for cardiovascular disease (CVD) and CHD deaths at 10 years. Clinical risk assessment incorporated the ASCVD risk score. For ML, an ensemble boosting approach was used to fit a predictive classifier for outcomes, followed by automated feature selection using information gain ratio. The model-building process incorporated all available clinical and CT data, including the CAC score; the number, volume, and density of CAC plaques; and extracoronary scores; comprising a total of 77 variables. The overall proposed model (ML all) was evaluated using a 10-fold cross-validation framework on the population data and area under the curve (AUC) as metrics. The prediction performance was also compared with 2 traditional scores (ASCVD risk and CAC score) and 2 additional models that were trained using all the clinical data (ML clinical) and CT variables (ML CT).

RESULTS

The AUC by ML all (0.845) for predicting CVD death was superior compared with those obtained by ASCVD risk alone (0.821), CAC score alone (0.781), and ML CT alone (0.804) (p < 0.001 for all). Similarly, for predicting CHD death, AUC by ML all (0.860) was superior to the other analyses (0.835 for ASCVD risk, 0.816 for CAC, and 0.827 for ML CT; p < 0.001).

CONCLUSIONS

The comprehensive ML model was superior to ASCVD risk, CAC score, and an ML model fitted using CT variables alone in the prediction of both CVD and CHD death.

Prognostic value of coronary artery calcium score, area, and density among individuals on statin therapy vs. non-users: The coronary artery calcium consortium

BACKGROUND AND AIMS

Statins do not decrease coronary artery calcium (CAC) and may increase existing calcification or its density. Therefore, we examined the prognostic significance of CAC among statin users at the time of CAC scanning.

METHODS

We included 28,025 patients (6151 statin-users) aged 40-75 years from the CAC Consortium. Cox regression models were used to assess the association of CAC with coronary heart disease (CHD) and cardiovascular disease (CVD) mortality. Models were adjusted for traditional CVD risk factors. Additionally, we examined the predictive performance of CAC components including CAC area, volume, and density using an age- and sex-adjusted Cox regression model.

RESULTS

Participants (mean age 53.9 ± 10.3 years, 65.0% male) were followed for median 11.2 years. There were 395 CVD and 182 CHD deaths. One unit increase in log CAC score was associated with increased risk of CVD mortality (hazard ratio (HR), 1.2; 95% CI = 1.1-1.3) and CHD mortality (HR, 1.2; 95% CI = 1.1-1.4)) among statin users. There was a small but significant negative interaction between CAC score and statin use for the prediction of CHD (p-value = 0.036) and CVD mortality (p-value = 0.025). The volume score and CAC area were similarly associated with outcomes in statin users and non-users. Density was associated with CVD and CHD mortality in statin naïve patients, but with neither in statin users.

CONCLUSION

CAC scoring retains robust risk prediction in statin users, and the changing relationship of CAC density with outcomes may explain the slightly weaker relationship of CAC with outcomes in statin users.

Coronary Artery Calcium as a Synergistic Tool for the Age- and Sex-Specific Risk of Cardiovascular and Cancer Mortality: The Coronary Artery Calcium Consortium

Background

Coronary artery calcium (CAC) is a predictor for the development of cardiovascular disease (CVD) and to a lesser extent cancer. The age‐ and sex‐specific relationship of CAC with CVD and cancer mortality is unknown.

Methods and Results

Asymptomatic patients aged 40 to 75 years old without known CVD were included from the CAC Consortium. We calculated sex‐specific mortality rates per 1000 person‐years’ follow‐up. Using parametric survival regression modeling, we determined the age‐ and sex‐specific CAC score at which the risk of death from CVD and cancer were equal. Among the 59 502 patients included in this analysis, the mean age was 54.9 (±8.5) years, 34% were women, and 89% were white. There were 671 deaths attributable to CVD and 954 deaths attributable to cancer over a mean follow‐up of 12±3 years. Among patients with CAC=0, cancer was the leading cause of death, the total mortality rate was low (women, 1.8; men, 1.5), and the CVD mortality rate was exceedingly low for women (0.3) and men (0.3). The age‐specific CAC score at which the risk of CVD and cancer mortality were equal had a U‐shaped relationship for women, while the relationship was exponential for men.

Conclusions

The age‐ and sex‐specific relationship of CAC with CVD and cancer mortality differed significantly for women and men. Our age‐ and sex‐specific CAC score provides a more precise estimate and further facilitates the use of CAC as a synergistic tool in strategies for the prediction and prevention of CVD and cancer mortality.

Predictors of coronary artery calcium among 20-30-year-olds: The Coronary Artery Calcium Consortium

BACKGROUND AND AIMS

We sought to understand the risk factor correlates of very early coronary artery calcium (CAC), and the potential investigational value of CAC phenotyping in adults aged 20-30 years.

METHODS

We studied all participants aged 20-30 years at baseline (N = 373) in the Coronary Artery Calcium Consortium, a large multi-center cohort study of patients aged 18 years or older without known atherosclerotic cardiovascular disease (ASCVD) at baseline, referred for CAC scoring for clinical risk stratification. We described the prevalence of CAC in men and women, the frequency of risk factors by the presence of CAC (CAC = 0 vs CAC >0), and assessed the association between traditional non-demographic CVD risk factors (hypertension, hyperlipidemia, smoking, family history of CHD, and diabetes) and prevalent CAC, using age- and sex-adjusted logistic regression models.

RESULTS

The mean age of the study participants was 27.5 ± 2.4 years; 324 (86.9%) had CAC = 0, and 49 (13.1%) had CAC >0. Among the 49 participants with CAC, 38 (77.6%) were men, and median CAC score was low at 4.6. In age- and sex-adjusted models, there was a graded increase in the odds of CAC >0 with increasing traditional cardiovascular disease (CVD) risk factor burden (p = 0.001 for linear trend). Participants with ≥3 traditional risk factors had a statistically significant higher odds of having prevalent CAC (OR 5.57, 95% CI; 1.82-17.03) compared to participants with no risk factors.

CONCLUSIONS

Our study demonstrates the non-negligible prevalence of CAC among very high-risk young US adults, reinforcing the critical importance of traditional risk factors in the earliest development of detectable subclinical ASCVD.

Comparing Risk Scores in the Prediction of Coronary and Cardiovascular Deaths: Coronary Artery Calcium Consortium

OBJECTIVES

This study compared risk discrimination for the prediction of coronary heart disease (CHD) and cardiovascular disease (CVD) deaths for the Pooled Cohort Equations (PCE), the MESA (Multi-Ethnic Study of Atherosclerosis) Risk Score (with and without coronary artery calcium [CAC]), and of simple addition of CAC to the PCE.

BACKGROUND

The PCE predict 10-year risk of atherosclerotic CVD events, and the MESA Risk Score predicts risk of CHD. Their comparative performance for the prediction of fatal events is poorly understood.

METHODS

We evaluated 53,487 patients ages 45 to 79 years from the CAC Consortium, a retrospective cohort study of asymptomatic individuals referred for clinical CAC scoring. Risk discrimination was measured using C-statistics.

RESULTS

Mean age was 57 years, 35% were women, and 39% had CAC of 0. There were 421 CHD and 775 CVD deaths over a mean 12-year follow-up. In the overall study population, discrimination with the MESA Risk Score with CAC and the PCE was almost identical for both outcomes (C-statistics: 0.80 and 0.79 for CHD death, 0.77 and 0.78 for CVD death, respectively). Addition of CAC to the PCE improved risk discrimination, yielding the largest C-statistics. The MESA Risk Score with CAC and the PCE plus CAC showed the best discrimination among the 45% of patients with 5% to 20% estimated risk. Secondary analyses by estimated CVD risk strata showed modestly improved risk discrimination with CAC also among low- and high-estimated risk groups.

CONCLUSIONS

Our findings support the current guideline recommendation to use, among available risk scores, the PCE for initial risk assessment and to use CAC for further risk assessment in a broad borderline and intermediate risk group. Also, in select individuals at low or high estimated risk, CAC modestly improved discrimination. Studies in unselected populations will lead to further understanding of the potential value of tools combining risk scores and CAC for optimal risk assessment.

The association of coronary artery calcium score and mortality risk among smokers: The coronary artery calcium consortium

BACKGROUND AND AIMS

Cardiovascular disease (CVD) and cancer are the two leading causes of death in smokers. Lung cancer screening is recommended in a large proportion of smokers. We examined the implication of coronary artery calcium (CAC) score (quantitative and qualitative) for cardiovascular disease (CVD), coronary heart disease (CHD), and cancer mortality risk prediction among current smokers.

METHODS

We included current smokers without known heart disease from the CAC Consortium. Cox regression (for all-cause mortality) and Fine-and-Gray competing-risk regression (for CVD, CHD, and cancer mortality) models, adjusted for traditional CVD risk factors, were used to assess the association between CAC and each mortality outcome, with CAC as a continuous (log2-transformed) or categorical variable (CAC = 0, CAC = 1-99, CAC = 100-399, and CAC ≥400). We used number of vessels with CAC as a surrogate for the qualitative measure of CAC and mortality outcomes. Analyses were repeated for lung cancer screening-eligible population (defined as ever smokers with >30 pack years smoking history) (n = 1,149). Hazard ratios (HR) for all-cause mortality and Subdistribution HRs (sHR) with 95% confidence intervals (CI) were reported.

RESULTS

Over a median of 11.9 years (25th-75th percentile: 10.2-13.3) of follow-up, of 5,147 current smokers (mean age 52.5 ± 9.4, 32.4% women) 337 died (102 of CVD, 54 of CHD, and 123 of cancer). A doubling of CAC score was associated with increased HRs of all-cause mortality (1.10 (1.06-1.14)), and sHRs for CVD (1.15 (1.07-1.24)), CHD (1.26 (1.11-1.42)) and cancer mortality (1.06 (1.00-1.13)). Those with CAC ≥400 had increased sHR of CVD (3.55 (1.70-7.41)), CHD (8.80 (2.41-32.10)), and cancer mortality (1.85 (1.07-3.22)), compared with those with CAC = 0. A diffuse CAC pattern significantly increased the risk of all-cause, CVD, and CHD mortality among smokers. Results were consistent for the lung cancer screening-eligible population.

CONCLUSIONS

Qualitative and quantitative CAC scores can prognosticate risk of all-cause, CVD, CHD, and cancer mortality beyond traditional risk factors among all smokers as well as those eligible for lung cancer screening.

All-cause and cause-specific mortality in individuals with zero and minimal coronary artery calcium: A long-term, competing risk analysis in the Coronary Artery Calcium Consortium

BACKGROUND AND AIMS

The long-term associations between zero, minimal coronary artery calcium (CAC) and cause-specific mortality are currently unknown, particularly after accounting for competing risks with other causes of death.

METHODS

We evaluated 66,363 individuals from the CAC Consortium (mean age 54 years, 33% women), a multi-center, retrospective cohort study of asymptomatic individuals undergoing CAC scoring for clinical risk assessment. Baseline evaluations occurred between 1991 and 2010.

RESULTS

Over a mean of 12 years of follow-up, individuals with CAC = 0 (45% prevalence, mean age 45 years) had stable low rates of coronary heart disease (CHD) death, cardiovascular disease (CVD) death (ranging 0.32 to 0.43 per 1000 person-years), and all-cause death (1.38-1.62 per 1000 person-years). Cancer was the predominant cause of death in this group, yet rates were also very low (0.47-0.79 per 1000 person-years). Compared to CAC = 0, individuals with CAC 1-10 had an increased multivariable-adjusted risk of CVD death only under age 40. Individuals with CAC>10 had multivariable-adjusted increased risks of CHD death, CVD death and all-cause death at all ages, and a higher proportion of CVD deaths.

CONCLUSIONS

CAC = 0 is a frequent finding among individuals undergoing CAC scanning for risk assessment and is associated with low rates of all-cause death at 12 years of follow-up. Our results support the emerging consensus that CAC = 0 represents a unique population with favorable all-cause prognosis who may be considered for more flexible treatment goals in primary prevention. Detection of any CAC in young adults could be used to trigger aggressive preventive interventions.

Role of Coronary Artery Calcium for Stratifying Cardiovascular Risk in Adults With Hypertension

We examined the utility of coronary artery calcium (CAC) for cardiovascular risk stratification among hypertensive adults, including those fitting eligibility for SPRINT (Systolic Blood Pressure Intervention Trial). Additionally, we used CAC to identify hypertensive adults with cardiovascular disease (CVD) mortality rates equivalent to those observed in SPRINT who may, therefore, benefit from the most intensive blood pressure therapy. Our study population included 16 167 hypertensive patients from the CAC Consortium, among whom 6375 constituted a "SPRINT-like" population. We compared multivariable-adjusted hazard ratios of coronary heart disease and CVD deaths by CAC category (0, 1-99, 100-399, ≥400). Additionally, we generated a CAC-CVD mortality curve for patients aged >50 years to determine what CAC scores were associated with CVD death rates observed in SPRINT. Mean age was 58.1±10.6 years. During a mean follow-up of 11.6±3.6 years, there were 409 CVD deaths and 207 coronary heart disease deaths. Increasing CAC scores were associated with increased coronary heart disease and CVD mortality (coronary heart disease-CAC 100-399: hazard ratio [95% CI] 1.88 [1.04-3.40], CAC ≥400: 4.16 [2.34-7.39]; CVD-CAC 100-399: 1.93 [1.31-2.83], CAC ≥400: 3.51 [2.40-5.13]). A similar increased risk was observed across 10-year atherosclerotic CVD risk categories and in the SPRINT-like population. A CAC score of 220 (confidence range, 165-270) was associated with the CVD mortality rate observed in SPRINT. CAC risk stratifies adults with hypertension, including those who are SPRINT eligible. A CAC score of 220 can identify hypertensive adults with SPRINT-level CVD mortality risk and, therefore, may be reasonable for identifying candidates for aggressive blood pressure therapy.

Interplay of Coronary Artery Calcium and Risk Factors for Predicting CVD/CHD Mortality: The CAC Consortium

OBJECTIVES

This study sought to evaluate the association and burden of coronary artery calcium (CAC) with long-term, cause-specific mortality across the spectrum of baseline risk.

BACKGROUND

Although CAC is a known predictor of short-term, all-cause mortality, data on long-term and cause-specific mortality are inadequate.

METHODS

The CAC Consortium cohort is a multicenter cohort of 66,636 participants without coronary heart disease (CHD) who underwent CAC testing. The following risk factors (RFs) were considered: 1) current cigarette smoking; 2) dyslipidemia; 3) diabetes mellitus; 4) hypertension; and 5) family history of CHD.

RESULTS

During the 12.5-years median follow-up, 3,158 (4.7%) deaths occurred; 32% were cardiovascular disease (CVD) deaths. Participants with CAC scores ≥400 had a significantly increased risk for CHD and CVD mortality (hazard ratio [HR]: 5.44; 95% confidence interval [CI]: 3.88 to 7.62; and HR: 4.15; 95% CI: 3.29 to 5.22, respectively) compared with CAC of 0. Participants with ≥3 RFs had a smaller increased risk for CHD and CVD mortality (HR: 2.09; 95% CI: 1.52 to 2.85; and HR: 1.84; 95% CI: 1.46 to 2.31, respectively) compared with those without RFs. Across RF strata, CAC added prognostic information. For example, participants without RFs but with CAC ≥400 had significantly higher all-cause, non-CVD, CVD, and CHD mortality rates compared with participants with ≥3 RFs and CAC of 0.

CONCLUSIONS

Across the spectrum of RF burden, a higher CAC score was strongly associated with long-term, all-cause mortality and a greater proportion of deaths due to CVD and CHD. Absence of CAC identified people with a low risk over 12 years of follow-up, with most deaths being non-CVD in nature, regardless of RF burden.

Race/Ethnicity and the Prognostic Implications of Coronary Artery Calcium for All-Cause and Cardiovascular Disease Mortality: The Coronary Artery Calcium Consortium

Background

Coronary artery calcium (CAC) predicts cardiovascular disease (CVD) events; however, less is known about how its prognostic implications vary by race/ethnicity.

Methods and Results

A total of 38 277 whites, 1621 Asians, 977 blacks, and 1349 Hispanics from the CAC Consortium (mean age 55 years, 35% women) were followed over a median of 11.7 years. Modeling CAC in continuous and categorical (CAC=0; CAC 1–99; CAC 100–399; CAC ≥400) forms, we assessed its predictive value for all‐cause and CVD mortality by race/ethnicity using Cox proportional hazards and Fine and Gray competing‐risk regression, respectively. We also assessed the impact of race/ethnicity on risk within individual CAC strata, using whites as the reference. Models were adjusted for traditional cardiovascular risk factors. Increased CAC was associated with higher total and CVD mortality risk in all race/ethnicity groups, including Asians. However, the risk gradient with increasing CAC was more pronounced in blacks and Hispanics. In Fine and Gray subdistribution hazards models adjusted for traditional cardiovascular risk factors and CAC (continuous), blacks (subdistribution hazard ratio 3.4, 95% confidence interval, 2.5–4.8) and Hispanics (subdistribution hazard ratio 2.3, 95% confidence interval, 1.6–3.2) showed greater risk of CVD mortality when compared with whites, while Asians had risk similar to whites. These race/ethnic differences persisted when CAC=0.

Conclusions

CAC predicts all‐cause and CVD mortality in all studied race/ethnicity groups, including Asians and Hispanics, who may be poorly represented by the Pooled Cohort Equations. Blacks and Hispanics may have greater mortality risk compared with whites and Asians after adjusting for atherosclerosis burden, with potential implications for US race/ethnic healthcare disparities research.

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

BACKGROUND

The 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.

METHODS

We 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.

RESULTS

The 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).

CONCLUSION

The 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

BACKGROUND

The 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.

METHODS

The 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.

RESULTS

This 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.

CONCLUSION

In 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.

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

BACKGROUND

Age- 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 RESULTS

Using 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.

CONCLUSIONS

A 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.

Rationale and design of the coronary artery calcium consortium: A multicenter cohort study

BACKGROUND

Although coronary artery calcium (CAC) has been investigated for over two decades, there is very limited data on the association of CAC with cause of death. The CAC Consortium is a large ongoing multi-center observational cohort of individuals who underwent non-contrast cardiac-gated CAC testing and systematic, prospective, long-term follow-up for mortality with ascertainment of cause of death.

METHODS

Four participating institutions from three states within the US (California, Minnesota, and Ohio) have contributed individual-level patient data to the CAC Consortium (spanning years 1991-2010). All CAC scans were clinically indicated and physician-referred in patients without a known history of coronary heart disease. Using strict inclusion and exclusion criteria to minimize missing data and to eliminate non-dedicated CAC scans (i.e. concomitant CT angiography), a sharply defined and well-characterized cohort of 66,636 patients was assembled. Mortality status was ascertained using the Social Security Administration Death Master File and a validated algorithm. In addition, death certificates were obtained from the National Death Index and categorized using ICD (International Classification of Diseases) codes into common causes of death.

RESULTS

Mean patient age was 54 ± 11 years and the majority were male (67%). Prevalence of CVD risk factors was similar across sites and 55% had a <5% estimated 10-year atherosclerotic cardiovascular disease (ASCVD) risk. Approximately 45% had a Calcium score of 0 and 11% had an Agatston Score ≥400. Over a mean follow-up of 12 ± 4 years, there were 3158 deaths (4.15 per 1000 person-years). The majority of deaths were due to cancer (37%) and CVD (32%). Most CVD deaths were due to CHD (54%) followed by stroke (17%). In general, CAC score distributions were similar across sites, and there were similar cause of death patterns.

CONCLUSIONS

The CAC Consortium is large and highly generalizable data set that is uniquely positioned to expand the understanding of CAC as a predictor of mortality risk across the spectrum of disease states, allowing innovative modeling of the competing risks of cardiovascular and non-cardiovascular death.

Randomized, double-blind, placebo-controlled, clinical study on the effect of Diabetinol(®) on glycemic control of subjects with impaired fasting glucose

BACKGROUND

This study investigated the efficacy of Diabetinol(®) in people with diabetes on medication but not meeting the American Association of Clinical Endocrinologists and American Diabetes Association glycemic, blood pressure, and lipid targets.

SUBJECTS AND METHODS

Fifty subjects, aged 18-75 years, with fasting blood glucose ≤15.4 mmol/L, hemoglobin A1c levels ≤12%, and a body mass index between 25 and 40 kg/m(2), were enrolled in a 24-week, randomized, double-blind, placebo-controlled, parallel study. Diabetinol(®) or placebo was administered as 2×525 mg capsules/day.

RESULTS

In the Diabetinol(®) group, 14.3% versus 0% in the placebo group, 33.3% versus 15.4% in placebo, 20.0% versus 12.5% in placebo, and 83.3% versus 60% in placebo achieved the American Association of Clinical Endocrinologists and American Diabetes Association targets for hemoglobin A1c, low-density lipoprotein, total cholesterol, and systolic blood pressure, respectively. There was no difference in the maximum concentration (Cmax) of serum glucose or area under the curve (AUC)0-240 minutes. The time to Cmax was longer for participants on Diabetinol(®) than placebo group at week 12 (P=0.01). Fasting blood glucose increased from baseline to week 24 in both groups; however, this increase was 14.3 mg/dL lower in the Diabetinol(®) group versus placebo. The Diabetinol(®) group showed an increase of 5.53 mg/dL in fasting insulin at week 12 (P=0.09) and 3.2 mg/dL at week 24 (P=0.41) over and above the placebo group. A decrease of 1.5% in total cholesterol, 5.8% in low-density lipoprotein, and a 1.6% increase in high-density lipoprotein concentrations were seen in the Diabetinol(®) group. Diabetinol(®) improved 6-month oral glucose tolerance test and 2-hour postprandial glucose profiles in participants between 40 and 60 years of age.

CONCLUSION

The current study suggests a role for Diabetinol(®) as an adjunctive therapy for glycemic maintenance and for decreasing the risk of diabetes-associated comorbidities in type 2 diabetic patients on conventional therapies.

Pantethine, a derivative of vitamin B5, favorably alters total, LDL and non-HDL cholesterol in low to moderate cardiovascular risk subjects eligible for statin therapy: a triple-blinded placebo and diet-controlled investigation

High serum concentration of low-density lipoprotein cholesterol (LDL-C) is a major risk factor for coronary heart disease. The efficacy of pantethine treatment on cardiovascular risk markers was investigated in a randomized, triple-blinded, placebo-controlled study, in a low to moderate cardiovascular disease (CVD) risk North American population eligible for statin therapy, using the National Cholesterol Education Program (NCEP) guidelines. A total of 32 subjects were randomized to pantethine (600 mg/day from weeks 1 to 8 and 900 mg/day from weeks 9 to 16) or placebo. Compared with placebo, the participants on pantethine showed a significant decrease in total cholesterol at 16 weeks (P=0.040) and LDL-C at 8 and 16 weeks (P=0.020 and P=0.006, respectively), and decreasing trends in non-high-density lipoprotein cholesterol at week 8 and week 12 (P=0.102 and P=0.145, respectively) that reached significance by week 16 (P=0.042). An 11% decrease in LDL-C from baseline was seen in participants on pantethine, at weeks 4, 8, 12, and 16, while participants on placebo showed a 3% increase at week 16. This decrease was significant between groups at weeks 8 (P=0.027) and 16 (P=0.010). The homocysteine levels for both groups did not change significantly from baseline to week 16. Coenzyme Q10 significantly increased from baseline to week 4 and remained elevated until week 16, in both the pantethine and placebo groups. After 16 weeks, the participants on placebo did not show significant improvement in any CVD risk end points. This study confirms that pantethine lowers cardiovascular risk markers in low to moderate CVD risk participants eligible for statins according to NCEP guidelines.

Mortality rates in smokers and nonsmokers in the presence or absence of coronary artery calcification

OBJECTIVES

The aim of this study was to further explore the interplay between smoking status, coronary artery calcium (CAC), and all-cause mortality.

BACKGROUND

Prior studies have not directly compared the relative prognostic impact of CAC in smokers versus nonsmokers. In particular, although a calcium score of zero (CAC = 0) is a known favorable prognostic marker, whether smokers with CAC = 0 have as good a prognosis as nonsmokers with CAC = 0 is unknown. Given that computed tomography (CT) screening for lung cancer appears effective in smokers, the relative prognostic implications of visualizing any CAC versus no CAC on such screening also deserve study.

METHODS

Our study cohort consisted of 44,042 asymptomatic individuals referred for noncontrast cardiac CT (age 54 ± 11 years, 54% men). Subjects were followed for a mean of 5.6 years. The primary endpoint was all-cause mortality.

RESULTS

Approximately 14% (n = 6,020) of subjects were active smokers at enrollment. There were 901 deaths (2.05%) overall, with increased mortality in smokers versus nonsmokers (4.3% vs. 1.7%, p < 0.0001). Smoking remained a risk factor for mortality across increasing strata of CAC scores (1 to 100, 101 to 400, and >400). At each stratum of elevated CAC score, mortality in smokers was consistently higher than mortality in nonsmokers from the CAC stratum above. In multivariable analysis within these strata, we found mortality hazard ratios of 3.8 (95% confidence interval [CI]: 2.8 to 5.2), 3.5 (95% CI: 2.6 to 4.9), and 2.7 (95% CI: 2.1 to 3.5), respectively, in smokers compared with nonsmokers. However, among the 19,898 individuals with CAC = 0, the mortality hazard ratio for smokers without CAC was 3.6 (95% CI: 2.3 to 5.7), compared with nonsmokers without CAC.

CONCLUSIONS

Smoking is a risk factor for death across the entire spectrum of subclinical coronary atherosclerosis. Smokers with any CAC had significantly higher mortality than smokers without CAC, a finding with implications for smokers undergoing lung cancer CT-based screening. However, the absence of CAC might not be as useful a "negative risk factor" in active smokers, because this group has mortality rates similar to nonsmokers with mild-to-moderate atherosclerosis.

Interplay of coronary artery calcification and traditional risk factors for the prediction of all-cause mortality in asymptomatic individuals

BACKGROUND

Current guidelines recommend the use of coronary artery calcium (CAC) scoring for intermediate-risk patients; however, the potential role of CAC among individuals who have no risk factors (RFs) is less established. We sought to examine the relationship between the presence and burden of traditional RFs and CAC for the prediction of all-cause mortality.

METHODS AND RESULTS

The study cohort consisted of 44,052 consecutive asymptomatic individuals free of known coronary heart disease referred for computed tomography for the assessment of CAC. The following RFs were considered: (1) current cigarette smoking, (2) dyslipidemia, (3) diabetes mellitus, (4) hypertension, and (5) family history of coronary heart disease. Patients were followed for a mean of 5.6 ± 2.6 years for the primary end point of all-cause mortality. Among individuals who had no RF, Cox proportional model adjusted for age and sex identified that increasing CAC scores were associated with 3.00- to 13.38-fold higher mortality risk. The lowest survival rate was observed in those with no CAC and no RF, whereas those with CAC ≥ 400 and ≥3 RFs had the highest all-cause fatality rate. Notably, individuals with no RF and CAC ≥ 400 had a substantially higher mortality rate compared with individuals with ≥3 RFs in the absence of CAC (16.89 versus 2.72 per 1000 person-years).

CONCLUSIONS

By highlighting that individuals without RFs but elevated CAC have a substantially higher event rates than those who have multiple RFs but no CAC, these findings challenge the exclusive use of traditional risk assessment algorithms for guiding the intensity of primary prevention therapies.

Potential implications of coronary artery calcium testing for guiding aspirin use among asymptomatic individuals with diabetes

OBJECTIVE

It is unclear whether coronary artery calcium (CAC) is effective for risk stratifying patients with diabetes in whom treatment decisions are uncertain.

RESEARCH DESIGN AND METHODS

Of 44,052 asymptomatic individuals referred for CAC testing, we studied 2,384 individuals with diabetes. Subjects were followed for a mean of 5.6 ± 2.6 years for the end point of all-cause mortality.

RESULTS

There were 162 deaths (6.8%) in the population. CAC was a strong predictor of mortality across age-groups (age <50, 50-59, ≥60), sex, and risk factor burden (0 vs. ≥1 additional risk factor). In individuals without a clear indication for aspirin per current guidelines, CAC stratified risk, identifying patients above and below the 10% risk threshold of presumed aspirin benefit.

CONCLUSIONS

CAC can help risk stratify individuals with diabetes and may aid in selection of patients who may benefit from therapies such as low-dose aspirin for primary prevention.

Pantethine, a derivative of vitamin B(5) used as a nutritional supplement, favorably alters low-density lipoprotein cholesterol metabolism in low- to moderate-cardiovascular risk North American subjects: a triple-blinded placebo and diet-controlled investigation

Safety and efficacy of a biologically active derivative of vitamin B(5) (pantethine) on total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) metabolism was studied in North American subjects at conventional low to moderate cardiovascular disease (CVD) risk. A total of 120 subjects initiated a therapeutic lifestyle change (TLC) diet 4 weeks before randomization (baseline) and maintained the diet throughout a 16-week study period; at baseline, subjects were randomized in a triple-blinded manner to either pantethine (600 mg/d, baseline to week 8, and 900 mg/d, weeks 9-16) or identically labeled, nonbiologically active placebo (n = 60 per group). We hypothesized that pantethine would lower TC and low-density lipoprotein in low-CVD-risk North American subjects in a similar manner as reported in high-CVD-risk subjects studied mainly in Italy and Japan. While sustaining a TLC diet and in comparison with placebo, pantethine demonstrated significant (P < .005) and sustained reductions (from baseline to week 16) in TC (6 mg/dL, 0.16 mmol/L, 3%), LDL-C (4 mg/dL, 0.10 mmol/L, 4%), and apolipoprotein B (4 mg/dL, 0.04 g/L, 5%). Our data suggest that pantethine supplementation for 16 weeks (600 mg/d for weeks 1-8 then 900 mg/d for weeks 9-16) is safe and significantly lowers TC and LDL-C over and above the effect of TLC diet alone. Although the absolute magnitude of these effects was small in these low- to moderate-risk North Americans (4-6 mg/dL), the results are noteworthy as prior studies have shown that, for each 1 mg/dL (0.026 mmol/L) reduction in LDL-C, there is a concomitant 1% reduction in overall future CVD risk.

Familial defective apolipoprotein B-100 and increased low-density lipoprotein cholesterol and coronary artery calcification in the old order amish

BACKGROUND

Elevated low-density lipoprotein cholesterol (LDL-C) levels are a major cardiovascular disease risk factor. Genetic factors are an important determinant of LDL-C levels.

METHODS

To identify single nucleotide polymorphisms associated with LDL-C and subclinical coronary atherosclerosis, we performed a genome-wide association study of LDL-C in 841 asymptomatic Amish individuals aged 20 to 80 years, with replication in a second sample of 663 Amish individuals. We also performed scanning for coronary artery calcification (CAC) in 1018 of these individuals.

RESULTS

From the initial genome-wide association study, a cluster of single nucleotide polymorphisms in the region of the apolipoprotein B-100 gene (APOB) was strongly associated with LDL-C levels (P < 10(-68)). Additional genotyping revealed the presence of R3500Q, the mutation responsible for familial defective apolipoprotein B-100, which was also strongly associated with LDL-C in the replication sample (P < 10(-36)). The R3500Q carrier frequency, previously reported to be 0.1% to 0.4% in white European individuals, was 12% in the combined sample of 1504 Amish participants, consistent with a founder effect. The mutation was also strongly associated with CAC in both samples (P < 10(-6) in both) and accounted for 26% and 7% of the variation in LDL-C levels and CAC, respectively. Compared with noncarriers, R3500Q carriers on average had LDL-C levels 58 mg/dL higher, a 4.41-fold higher odds (95% confidence interval, 2.69-7.21) of having detectable CAC, and a 9.28-fold higher odds (2.93-29.35) of having extensive CAC (CAC score ≥400).

CONCLUSION

The R3500Q mutation in APOB is a major determinant of LDL-C levels and CAC in the Amish.

Relation of aortic valve calcium detected by cardiac computed tomography to all-cause mortality

Aortic valve calcium (AVC) can be quantified on the same computed tomographic scan as coronary artery calcium (CAC). Although CAC is an established predictor of cardiovascular events, limited evidence is available for an independent predictive value for AVC. We studied a cohort of 8,401 asymptomatic subjects (mean age 53 ± 10 years, 69% men), who were free of known coronary heart disease and were undergoing electron beam computed tomography for assessment of subclinical atherosclerosis. The patients were followed for a median of 5 years (range 1 to 7) for the occurrence of mortality from any cause. Multivariate Cox regression models were developed to predict all-cause mortality according to the presence of AVC. A total of 517 patients (6%) had AVC on electron beam computed tomography. During follow-up, 124 patients died (1.5%), for an overall survival rate of 96.1% and 98.7% for those with and without AVC, respectively (hazard ratio 3.39, 95% confidence interval 2.09 to 5.49). After adjustment for age, gender, hypertension, dyslipidemia, diabetes mellitus, smoking, and a family history of premature coronary heart disease, AVC remained a significant predictor of mortality (hazard ratio 1.82, 95% confidence interval 1.11 to 2.98). Likelihood ratio chi-square statistics demonstrated that the addition of AVC contributed significantly to the prediction of mortality in a model adjusted for traditional risk factors (chi-square = 5.03, p = 0.03) as well as traditional risk factors plus the presence of CAC (chi-square = 3.58, p = 0.05). In conclusion, AVC was associated with increased all-cause mortality, independent of the traditional risk factors and the presence of CAC.

Using noncontrast cardiac CT and coronary artery calcification measurements for cardiovascular risk assessment and management in asymptomatic adults

The presence of mural calcification has, for decades, been recognized as a marker for atheromatous plaque in the coronary arteries and the aorta, but only in the past decade has the application of noncontrast computed tomography (CT) been shown to be a reproducible, safe, and convenient test, which now is available worldwide. However, awareness of coronary artery calcium scanning is insufficient and the practitioner must be aware of the available literature as well as understanding clinical recommendations for applications and interpretation. It is best applied in the medium/intermediate risk, asymptomatic adult regardless of ethnicity across broad age ranges for both men and women; additional prognostic information is also afforded from the calcium distribution in the coronary artery system. Additionally, information can also be derived from the same CT scan regarding heart and aorta size and assessment of the epicardial fat pad (an anatomic marker for the metabolic syndrome). Details of how this test can aid in cardiovascular risk assessment and management in adults are provided.

Outcome of coronary plaque burden: a 10-year follow-up of aggressive medical management

Background

The effect of aggressive medical therapy on quantitative coronary plaque burden is not generally known, especially in ethnic Chinese.

Aims

We reasoned that Cardiac CT could conveniently quantify early coronary atherosclerosis in our patient population, and hypothesized that serial observation could differentiate the efficacy of aggressive medical therapy regarding progression and regression of the atherosclerotic process, as well as evaluating the additional impact of life-style modification and the relative effects of the application of statin therapy.

Methods

We employed a standardized Cardiac CT protocol to serially scan 113 westernized Hong Kong Chinese individuals (64 men and 49 women) with Chest Pain and positive coronary risk factors. In all cases included for this serial investigation, subsequent evaluation showed no significantly-obstructive coronary disease by functional studies and angiography. After stringent risk factor modification, including aggressive statin therapy to achieve LDL-cholesterol lowering conforming to N.C.E.P. ATP III guidelines, serial CT scans were performed 1-12 years apart for changes in coronary artery calcification (CAC), using the Agatston Score (AS) for quantification.

Results

At baseline, the mean AS was 1413.6 for males (mean age 54.4 years) and 2293.3 for females (mean age 62.4 years). The average increase of AS in the entire study population was 24% per year, contrasting with 16.4% per year on strict risk factor modification plus statin therapy, as opposed to 33.2% per year for historical control patients (p < 0.001). Additionally, 20.4% of the 113 patients demonstrated decreasing calcium scores. Medical therapy also yielded a remarkably low adverse event rate during the follow-up period --- 2 deaths, 2 strokes and only 1 case requiring PCI.

Conclusions

This study revealed that aggressive medical therapy can positively influence coronary plaque aiding in serial regression of calcium scores.

Absence of coronary artery calcification and all-cause mortality

OBJECTIVES

We sought to quantify the mortality rates associated with absent and low positive (CAC 1 to 10) coronary artery calcium (CAC).

BACKGROUND

There is increasing interest in the absence of CAC as a "negative" cardiovascular risk factor. However, published event rates for individuals with no CAC vary, likely owing to differences in baseline risk, follow-up period, and outcome ascertainment. The prognostic significance of low CAC (CAC 1 to 10) is not well described.

METHODS

Annualized all-cause mortality rates were assessed in 44,052 consecutive asymptomatic patients referred for CAC testing. Mean follow-up of the cohort was 5.6 +/- 2.6 years (range 1 to 13 years).

RESULTS

A total of 19,898 patients (45%) had no CAC on screening electron beam tomography, whereas 5,388 (12%) had low levels of CAC (CAC 1 to 10), and 18,766 (43%) had CAC >10. There were 104 deaths in those with no CAC (0.52%), 58 deaths in those with CAC 1 to 10 (1.06%), and 739 deaths in those with CAC >10 (3.96%). Annualized all-cause mortality rates for CAC = 0, CAC 1 to 10, and CAC >10 were 0.87, 1.92, and 7.48 deaths/1,000 person-years, respectively. The hazard ratio (HR) for all-cause mortality among CAC 1 to 10 versus CAC = 0 after adjustment for traditional risk factors was 1.99 (95% confidence interval [CI]: 1.44 to 2.75). Smoking (HR: 3.97, 95% CI: 2.75 to 5.41) and diabetes mellitus (HR: 3.36, 95% CI: 2.09 to 5.41) were associated with few events observed in CAC = 0 group.

CONCLUSIONS

In appropriately selected asymptomatic patients, the absence of CAC predicts excellent survival with 10-year event rates of approximately 1%. A finding of 0 CAC might be used as a rationale to emphasize lifestyle therapies rather than pharmacotherapy and to forgo repeated imaging studies. Individuals with low CAC score (CAC 1 to 10) are at increased risk above individuals with a 0 score and could be considered a distinct risk group by physicians and investigators.