Coronary Artery Calcium and Electron Beam Computed Tomography


Wong ND, Sciammarella MG, Polk D, Gallagher A, Miranda-Peats L, Whitcomb B, Hachamovitch R, Friedman JD, Hayes S, Berman DS.
The metabolic syndrome, diabetes, and subclinical atherosclerosis assessed by coronary calcium.
J Am Coll Cardiol. 2003 May 7;41(9):1547-53. Unique ID: 12742296. Abstract: OBJECTIVES: We compared the prevalence and extent of coronary artery calcium (CAC) among persons with the metabolic syndrome (MetS), diabetes, and neither condition. BACKGROUND: The prevalence and extent of CAC has not been compared among those with MetS, diabetes, or neither condition. METHODS: Of 1,823 persons (36% female) age 20 to 79 years who had screening for CAC by computed tomography, 279 had MetS, 150 had diabetes, and the remainder (n = 1,394) had neither condition. Metabolic syndrome was defined with >or=3 of the following: body mass index >or=30 kg/m(2); high-density lipoprotein cholesterol <40 mg/dl if male or <50 mg/dl if female; triglycerides >or=150 mg/dl; blood pressure >or=130/85 mm Hg or on treatment; or fasting glucose 110 to 125 mg/dl. The prevalence and odds of any and significant (>or=75th percentile) CAC among these groups and by number of MetS risk factors were determined. RESULTS: Those with neither MetS nor diabetes, MetS, or diabetes had a prevalence of CAC of 53.5%, 58.8%, and 75.3% (p < 0.001), respectively, among men and 37.6%, 50.8%, and 52.6% (p < 0.001), respectively, among women. Coronary artery calcium increased by the number (0 to 5) of MetS risk factors (from 34.0% to 58.3%) (p < 0.001). Forty-one percent of subjects with MetS had either a >20% 10-year risk of CHD or CAC >or=75th percentile for age and gender. Risk factor-adjusted odds for the presence of CAC were 1.40 (95% confidence interval [CI] 1.05 to 1.87) among those with MetS and 1.67 (95% CI 1.12 to 2.50) among those with diabetes, versus those with neither condition. CONCLUSIONS: Those with MetS or diabetes have an increased likelihood of CAC compared with those having neither condition.

Qu W, Le TT, Azen SP, Xiang M, Wong ND, Doherty TM, Detrano RC.
Value of coronary artery calcium scanning by computed tomography for predicting coronary heart disease in diabetic subjects.
Diabetes Care. 2003 Mar;26(3):905-10. Unique ID: 12610057. Abstract:OBJECTIVE: The South Bay Heart Watch is a cohort study designed to determine the significance of coronary calcium in high-risk asymptomatic patients. This is a report of the relative risk (RR) for outcomes of coronary artery calcium in diabetic and nondiabetic subjects. RESEARCH DESIGN AND METHODS: A total of 1312 diabetic and nondiabetic subjects underwent risk factor screening and computed tomography testing for coronary calcium at baseline and were followed clinically for 6.3 +/- 1.4 years. End points were either 1). hard events of nonfatal myocardial infarction (MI) or coronary death or 2). any cardiovascular event (nonfatal MI, coronary death, coronary revascularization, or stroke). RESULTS: The incidence rates of a hard event and any cardiovascular event for diabetic and nondiabetic subjects were 14.5 and 6.1% and 23.8 and 12.2%, respectively (P < 0.001). Cox regression analyses of the combined risk relationship of diabetes status and calcium score demonstrated that relative to nondiabetic subjects with low calcium scores (<2.8), diabetic subjects with calcium scores >or=2.8 exhibited at least a fourfold increase in the risk of either a hard or any cardiovascular event (P < 0.001). Cox regression analyses conducted separately for nondiabetic and diabetic subjects revealed that coronary calcium score risk groups were significantly associated with events in nondiabetic subjects (RR >or= 2.6, P 0.05). CONCLUSIONS: The risk of coronary heart disease increases with increasing calcium scores and diabetes status. Calcium scores have less prognostic value in diabetic subjects.


Wong ND, Budoff MJ, Pio J, Detrano RC.
Coronary calcium and cardiovascular event risk: evaluation by age- and sex-specific quartiles.
Am Heart J. 2002 Mar;143(3):456-9. Unique ID: 11868051. Abstract:BACKGROUND: Wide differences in risks for cardiovascular disease (CVD) events associated with coronary artery calcium (CAC) have been reported. We evaluated the relationship of the coronary calcium quartile, on the basis of age-sex cut points from a large sample of asymptomatic patients, to CVD events as a possible standardized means for reporting event risks associated with CAC, in comparison with quartiles of absolute CAC scores. METHODS: We applied age/sex-stratified cut points to 928 asymptomatic men and women (mean age 54 years) followed up for an average of 3.3 years, during which 28 CVD events were confirmed. Cox regression was used to evaluate the relation of the 2nd, 3rd, and 4th quartiles (compared with the 1st), with and without age/sex stratification, to the risk of future CVD events. RESULTS: The number of events (and percent incidence) that occurred in the 1st, 2nd, 3rd, and 4th quartiles of coronary calcium was 4 (0.9%), 2 (2.0%), 9 (4.5%), and 13 (6.4%) events (P =.001) for the age/sex-stratified quartiles and 4 (1.0%), 0 (0%), 7 (3.0%), and 17 (7.3%) for the absolute score quartiles (P =.001). In multivariable analysis adjusted for other risk factors, there was a modest increase in CVD events seen among those in the 3rd quartile (relative risk [RR] 4.3, P =.02), with a greater risk seen among those in the 4th quartile (RR 6.0, P <.01) (compared with the 1st quartile). This did not differ from use of absolute CAC scores, where RR = 2.6 (P =.14) for the 3rd quartile and RR = 6.4 (P <.01) for the 4th quartile. CONCLUSIONS: Our results suggest that age-sex stratification by percentile rank of CAC is as accurate as absolute CAC scores for predicting CVD events in asymptomatic persons. Ongoing longitudinal population-based studies will provide more definitive data.


Wong ND, Hsu JC, Detrano RC, Diamond G, Eisenberg H, Gardin JM.
Coronary artery calcium evaluation by electron beam computed tomography and its relation to new cardiovascular events.
Am J Cardiol. 2000 Sep 1;86(5):495-8. Unique ID: 11009264. Abstract: BACKGROUND: Electron beam computed tomography is widely used to screen for coronary artery calcium (CAC). We evaluated the relation of CAC to future cardiovascular disease events in 926 asymptomatic persons (735 men and 191 women, mean age 54 years) who underwent a baseline electron beam computed tomographic scan. All subjects included in this report returned a follow-up questionnaire 2 to 4 years (mean 3.3) after scanning, inquiring about myocardial infarction, stroke, and revascularizations. Sixty percent of men and 40% of women had a positive scan at baseline. Twenty-eight cardiovascular events occurred and were confirmed by blinded medical record review. The presence of CAC (a total calcium score of >0) and increasing score quartiles were related to the occurrence of new myocardial infarction (p <0.05), revascularizations (p <0.001), and total cardiovascular events (p <0.001). Those with scores at or above the median (score of 5) had a relative risk of 4.5 (p <0.01) for new events. From Cox regression models, adjusted for age, gender, and coronary risk factors, the relative risks for those with scores of 81 to 270 and -271 (compared with 0) for cardiovascular events were 4.5 (p <0.05) and 8.8 (p <0.001), respectively. These data support previous reports showing CAC to be a modest predictor of future cardiovascular events.


Wong ND; Hsu JC; Detrano RC; Diamond G; Eisenberg H; Gardin JM.
Coronary artery calcium evaluation by electron beam computed tomography and its relation to new cardiovascular events.
American Journal of Cardiology, 2000 Sep 1, 86(5):495-8. Unique ID: 20462788. Abstract: Electron beam computed tomography is widely used to screen for coronary artery calcium (CAC). We evaluated the relation of CAC to future cardiovascular disease events in 926 asymptomatic persons (735 men and 191 women, mean age 54 years) who underwent a baseline electron beam computed tomographic scan. All subjects included in this report returned a follow-up questionnaire 2 to 4 years (mean 3.3) after scanning, inquiring about myocardial infarction, stroke, and revascularizations. Sixty percent of men and 40% of women had a positive scan at baseline. Twenty-eight cardiovascular events occurred and were confirmed by blinded medical record review. The presence of CAC (a total calcium score of >0) and increasing score quartiles were related to the occurrence of new myocardial infarction (p <0.05), revascularizations (p <0.001), and total cardiovascular events (p <0.001). Those with scores at or above the median (score of 5) had a relative risk of 4.5 (p <0.01) for new events. From Cox regression models, adjusted for age, gender, and coronary risk factors, the relative risks for those with scores of 81 to 270 and -271 (compared with 0) for cardiovascular events were 4.5 (p <0.05) and 8.8 (p <0.001), respectively. These data support previous reports showing CAC to be a modest predictor of future cardiovascular events.


Detrano RC; Wong ND; Doherty TM; Shavelle RM; Tang W; Ginzton LE; Budoff MJ; Narahara KA.
Coronary calcium does not accurately predict near-term future coronary events in high-risk adults.
Circulation, 1999 May 25, 99(20):2633-8. Unique ID: 99270843.

Abstract: BACKGROUND: Prognostic risk models have had limited success in predicting coronary events in subjects with multiple risk factors. We and others have proposed an alternative approach using radiographically detectable coronary calcium. We evaluated and compared the predictive value of these 2 approaches for determining coronary event risk in asymptomatic adults with multiple coronary risk factors. In addition, we assessed the predictive value of a risk model that included calcium score and cardiac risk-factor data. METHODS AND RESULTS: We recruited 1196 asymptomatic high-coronary-risk subjects who then underwent risk-factor assessment and cardiac electron-beam CT (EBCT) scanning and were followed up for 41 months with a 99% success rate. We applied the Framingham model and our data-derived risk model to determine the 3-year likelihood of a coronary event. The mean age of our cohort was 66 years, and mean 3-year Framingham risk was 3.3+/-3.6%. Sixty-eight percent (818 subjects) had detectable coronary calcium. There were 17 coronary deaths (1.4%) and 29 nonfatal infarctions (2. 4%). The receiver operating characteristic (ROC) curve areas calculated from the Framingham model, our data-derived risk model, and the calcium score were 0.69+/-0.05, 0.68+/-0.05, and 0.64+/-0.05, respectively (P=NS). When calcium score was included as a variable in the data-derived model, the ROC area did not change significantly (0.68+/-0.05 to 0.71+/-0.04; P=NS). CONCLUSIONS: Neither risk-factor assessment nor EBCT calcium is an accurate event predictor in high-risk asymptomatic adults. EBCT calcium score does not add significant incremental information to risk factors, and its use in clinical screening is not justified at this time.


Wong ND; Detrano RC; Diamond G; Rezayat C; Mahmoudi R; Chong EC; Tang W; Puentes G; Kang X; Abrahamson D.
Does coronary artery screening by electron beam computed tomography motivate potentially beneficial lifestyle behaviors?
American Journal of Cardiology, 1996 Dec 1, 78(11):1220-3. Unique ID: 97119907.

Abstract: We evaluated the extent to which cardiovascular risk-reducing behaviors are initiated as a result of knowledge of newly detected coronary artery disease, based on test results from noninvasive electron beam computed tomography (EBCT). A total of 703 men and women, aged 28 to 84 years, asymptomatic and without prior coronary disease, who had a baseline EBCT coronary artery scan and basic medical history and risk factor information completed a follow-up survey questioning them about health behaviors undertaken since their scan. Baseline calcium scores were significantly higher in those who subsequently reported consulting with a physician, or reported new hospitalization, coronary revascularization, beginning aspirin usage, blood pressure medications, cholesterol-lowering therapy, decreasing dietary fat, losing weight, beginning vitamin E, and under more worry (all p <0.01). Other factors, including reducing time worked, obtaining life insurance, losing employment, increased work absenteeism, increasing exercise, or stopping smoking were not associated with coronary calcium. In logistic regression, after adjusting for age, gender, pre-existing high cholesterol, high blood pressure, cigarette smoking, and a positive family history of coronary disease, the natural log of total calcium score remained associated with new aspirin usage, new cholesterol medication, consulting with a physician, losing weight, decreasing dietary fat, new coronary revascularization (all p <0.01), but also new hospitalization (p <0.05) and increased worry (p <0.001). The results suggest that potentially important risk-reducing behaviors may be reinforced by the knowledge of a positive coronary artery scan, independent of preexisting coronary risk factor status.


Detrano RC; Wong ND; Doherty TM; Shavelle R.
Prognostic significance of coronary calcific deposits in asymptomatic high-risk subjects.
American Journal of Medicine, 1997 Apr, 102(4):344-9. (UI: 97360651)
Abstract: PURPOSE: To determine the predictive value of coronary calcifications for coronary heart disease events in high-risk, asymptomatic adults: PATIENTS AND METHODS: A prospective cohort study of 1,461 high-risk, asymptomatic subjects were followed for 55 months with a 98% success rate. Coronary risk factor assessment and cardiac fluoroscopy with digital subtraction enhancement were performed to determine the number of calcified coronary arteries. RESULTS: Fifty-eight percent of this cohort (852 subjects) had fluoroscopically detectable coronary calcification: 437 (30%) had calcium in one, 253 (17%) in two, and 162 (11%) in all three coronary vessels. There were 90 (6%) deaths, 35 (39%) attributable to coronary heart disease, and 43 (3%) nonfatal myocardial infarctions. Subjects with calcification in more than one major coronary artery were 2.2 times more likely to suffer coronary death or nonfatal infarction (P = 0.001) than were subjects with one or no calcified arteries. Multivariable logistic regression analysis showed that only the number of calcified arteries, age, total cholesterol, history of diabetes, and left ventricular hypertrophy by electrocardiogram were associated independently with the incidence of coronary death or infarction in these subjects. CONCLUSIONS: Coronary calcification predicts coronary heart disease death or infarction in high-risk asymptomatic adults as well as do standard risk factors.


Wong ND; Detrano RC; Diamond G; Rezayat C; Mahmoudi R; Chong EC; Tang W; Puentes G; Kang X; Abrahamson D.
Does coronary artery screening by electron beam computed tomography motivate potentially beneficial lifestyle behaviors? [see comments].
American Journal of Cardiology, 1996 Dec 1, 78(11):1220-3. (UI: 97119907)
Abstract: We evaluated the extent to which cardiovascular risk-reducing behaviors are initiated as a result of knowledge of newly detected coronary artery disease, based on test results from noninvasive electron beam computed tomography (EBCT). A total of 703 men and women, aged 28 to 84 years, asymptomatic and without prior coronary disease, who had a baseline EBCT coronary artery scan and basic medical history and risk factor information completed a follow-up survey questioning them about health behaviors undertaken since their scan. Baseline calcium scores were significantly higher in those who subsequently reported consulting with a physician, or reported new hospitalization, coronary revascularization, beginning aspirin usage, blood pressure medications, cholesterol-lowering therapy, decreasing dietary fat, losing weight, beginning vitamin E, and under more worry (all p <0.01). Other factors, including reducing time worked, obtaining life insurance, losing employment, increased work absenteeism, increasing exercise, or stopping smoking were not associated with coronary calcium. In logistic regression, after adjusting for age, gender, pre-existing high cholesterol, high blood pressure, cigarette smoking, and a positive family history of coronary disease, the natural log of total calcium score remained associated with new aspirin usage, new cholesterol medication, consulting with a physician, losing weight, decreasing dietary fat, new coronary revascularization (all p <0.01), but also new hospitalization (p <0.05) and increased worry (p <0.001). The results suggest that potentially important risk-reducing behaviors may be reinforced by the knowledge of a positive coronary artery scan, independent of preexisting coronary risk factor status.


Teng W; Wong ND; Abrahamson D; Gardin JM.
Relation of electron beam computed tomography screening for coronary calcium to cardiovascular risk and disease: a review.
Coronary Artery Disease, 1996 May, 7(5):383-9.
Pub type: JOURNAL ARTICLE; REVIEW; REVIEW, TUTORIAL. (UI: 97019731)
Abstract: Electron beam computed tomography has become an increasingly popular technology to noninvasively screen for coronary artery calcium as a marker of atherosclerotic burden. Coronary artery calcium is invariably associated with atherosclerosis, and the amount (volume, mass, or calculated 'score') of calcium is directly associated with age, male gender, and other cardiovascular risk factors. Coronary artery calcium is highly sensitive and moderately specific for the identification of angiographically significant disease. Recent reports also show a direct association between the amount of coronary calcium and the risk of combined new coronary events and revascularization in previously asymptomatic individuals, and hard coronary events among symptomatic patients. Coronary artery screening by electron beam computed tomography is a cost-effective tool compared with other diagnostic modalities when the pre-test likelihood of disease is low to moderate. Although some reports have shown significant retest variability in calcium scores obtained from repeated scans, and in the individual relationship between angiographic disease and coronary calcium quantity, such variability may be minimized by averaging results from two or more consecutive scans, techniques to minimize respiratory motion artifact, and possibly the use of thicker scan slice thicknesses. Serial scanning by electron beam computed tomography is also being investigated as a noninvasive tool for following the effects of medical or lifestyle intervention for controlling cardiovascular risk factors or disease. At present, coronary artery scanning by electron beam computed tomography may be most appropriately utilized in screen patients with established coronary risk factors or known or suspected coronary disease, and in combination with established diagnostic testing to confirm the presence of suspected coronary disease.


Detrano RC; Wong ND; French WJ; Tang W; Georgiou D; Young E; Brezden OS; Doherty T; Brundage BH.
Prevalence of fluoroscopic coronary calcific deposits in high-risk asymptomatic persons.
American Heart Journal, 1994 Jun, 127(6):1526-32. (UI: 94256335)
Abstract: Coronary calcific deposits are always associated with coronary atherosclerosis. Sensitive radiographic technology can detect coronary calcium before atherosclerosis becomes symptomatic. A total of 1461 asymptomatic high-risk adult subjects were studied with digital subtraction fluoroscopy to detect coronary calcium. Risk factor data were recorded including age, sex, family history, smoking history, diabetes history, body mass index, systolic blood pressure, left ventricular hypertrophy on ECG, total serum cholesterol level, high-density lipoprotein (HDL) cholesterol, and total cholesterol/HDL ratio. Digital subtraction fluoroscopy in the left anterior oblique projection was performed in all subjects. The prevalence of calcific deposits in at least one major coronary artery was high (58.3%). Eleven percent had coronary calcium in all three major arteries. Multivariate logistic regression analysis showed significant correlations (p less than 0.05) between the prevalence of coronary calcium and age, smoking history (relative risk = 1.30), diabetes history (relative risk = 1.24), and family history (relative risk = 1.26). In older subjects (at least 65 years of age), smoking and serum lipoproteins assumed greater importance as contributors to coronary calcium, whereas in younger subjects a history of diabetes was more significant. Coronary calcific deposits are prevalent in high-risk asymptomatic subjects. Their occurrence is closely related to most known risk factors.


Wong ND; Vo A; Abrahamson D; Tobis JM; Eisenberg H; Detrano RC.
Detection of coronary artery calcium by ultrafast computed tomography and its relation to clinical evidence of coronary artery disease.
American Journal of Cardiology, 1994 Feb 1, 73(4):223-7. (UI: 94127419)
Abstract: Ultrafast computed tomography (CT) was used to evaluate the relation of coronary artery calcium, a marker of atherosclerosis, with a reported history of coronary artery disease (CAD) in 928 men and 290 women (mean age 53 +/- 10 years; 11% with previous CAD). Total calcium score was calculated as the sum of each lesion-specific score, calculated as the product of pixel area and density > 130 Hounsfeld units. Total score was 3 to 6 times greater (p less than 0.01) and the probability of coronary artery calcium 30 to 40% greater (p less than 0.01) in patients with a reported history of myocardial infarction, positive angiography, bypass surgery or angioplasty. From score cutoffs ranging from 1 to 500 for defining calcium, a negative test was accurate 93 to 98% of the time in ruling out CAD, whereas specificity increased from 43 to 93%; however, sensitivity decreased from 92 to 42%. A score cutoff of 50 showed modest sensitivity (78%) and specificity (71%); however, the predictive value for CAD from a positive test remained low (less than or = 40%), regardless of score cutoff. From multiple logistic regression, total score was also an independent indicator of CAD after considering any effects due to age, sex and other CAD risk factors. Further study is needed to document the long-term prognostic use of coronary calcium screening, including criteria that best project future risk of CAD.


Wong ND; Kouwabunpat D; Vo AN; Detrano RC; Eisenberg H; Goel M; Tobis JM.
Coronary calcium and atherosclerosis by ultrafast computed tomography in asymptomatic men and women: relation to age and risk factors.
American Heart Journal, 1994 Feb, 127(2):422-30.(UI: 94127376)
Abstract: We evaluated 675 men and 190 women who had no symptoms or history of clinical CHD, to determine the prevalence and risk factor correlates of CAC deposits as a marker of atherosclerosis. Measurements were taken noninvasively by ultrafast CT. The presence and extent of CAC deposits as measured by ultrafast CT was determined in all subjects, who also received personal and family medical history and risk factor questionnaire. The prevalence of CAC deposits increased significantly with age, ranging from 15% and 30% in men and women, respectively, less than 40 years of age to 93% and 75% in those aged > or = 70 years. Prevalence and total score also increased by the number of risk factors present, although in those aged > 60 years a high prevalence (> 80% in men) of calcium was present regardless of the presence of risk factors. In multiple logistic regression, age, male gender, hypertension, diabetes, hypercholesterolemia, and obesity were independently associated with CAC deposits. These results suggest a high prevalence of atherosclerosis with increasing age and the presence of risk factors in men and women who have no symptoms. Studies to determine the prognostic value of CAC in individuals with no symptoms are needed to determine which populations may benefit most from CAC deposit screening.


Goel M; Wong ND; Eisenberg H; Hagar J; Kelly K; Tobis JM.
Risk factor correlates of coronary calcium as evaluated by ultrafast computed tomography.
American Journal of Cardiology, 1992 Oct 15, 70(11):977-80.(UI: 93034969)
Abstract: Coronary artery calcium is invariably associated with atherosclerosis and has been linked to an increased risk of coronary events. Ultrafast computed tomography (CT) was recently used to document the presence and relative quantity of coronary calcium. The use of the self-reported coronary risk factors to identify persons with coronary calcium as documented by ultrafast CT screening was examined in 458 men and 139 women aged 26 to 81 years (88% asymptomatic). All subjects underwent ultrafast CT scanning, and received a questionnaire and underwent an interview regarding medical and risk factor history. Total calcium score was calculated as the sum of lesion-specific scores, each calculated as the product of density > or = 130 Hounsfield units and area > or = 0.51 mm2. The prevalence of coronary calcium increased significantly (p less than 0.01) by age group, and the greater the number of risk factors present, the greater the likelihood of calcium. From multiple logistic regression, age (p less than 0.01), male sex (relative risk [RR] 3.03; p less than 0.01), and history of smoking (RR 1.85; p less than 0.01) and hypertension (RR 1.65; p less than 0.05) were independently associated with the probability of detectable calcium. Among asymptomatic subjects, an association with hypercholesterolemia was also seen (RR 1.56; p less than 0.05). The results demonstrate that cardiovascular risk factors can help in identifying the likelihood of coronary calcium.



Last Updated April 2, 2001