Noninvasive prediction of coronary atherosclerosis by quantification of coronary artery calcification using electron beam computed tomography: comparison with electrocardiographic and thallium exercise stress test results

Typical angina during exercise stress testing improves the prediction of future acute coronary syndrome

INTRODUCTION

The prognostic value of angina during exercise stress testing is controversial, possibly due to previous studies not differentiating typical from non-typical angina. We aimed to assess the prognostic value of typical angina alone, or in combination with ST depression, during exercise stress testing for predicting cardiovascular events.

METHODS

We conducted a prospective observational cohort study including all patients who performed a clinical exercise stress test at the department of Clinical Physiology, Kalmar County Hospital between 2005 and 2012. The association between typical angina/ST depression and incident acute coronary syndrome (ACS) and cardiovascular mortality were analysed using Cox regression for long-term and 1-year follow-up.

RESULTS

Out of 11605 patients (median follow-up 6.7 years), 623 (5.4%) developed ACS and 319 (2.7%) died from cardiovascular causes. Compared to patients with no angina and no ST depression, typical angina and ST depression were associated with increased risk of future ACS; hazard ratio (HR) 3.5 ([95%CI] 2.6-4.7). This association was even stronger for ACS within one year (typical angina with and without concomitant ST depression; HR 20.8 (13.9-31.3) and 9.7 (6.1-15.4), respectively). Concordance statistics for ST depression in predicting ACS during long-term follow-up was 0.58 (0.56-0.60) and 0.69 (0.65-0.73) for ACS within one year, and 0.64 (0.62-0.66) and 0.77 (0.73-0.81), respectively, when typical angina was added to the model.

CONCLUSIONS

Typical angina during exercise stress testing is predictive of future ACS, especially in combination with ST depression, and during the first year after the test.

Transluminal attenuation gradient in coronary computed tomography angiography for determining stenosis severity of calcified coronary artery: a primary study with dual-source CT

OBJECTIVES

To evaluate the diagnostic accuracy of transluminal attenuation gradient (TAG) for stenosis severity of calcified lesions assessed by coronary computed tomography angiography (CCTA).

METHODS

One hundred seven patients who underwent CCTA and coronary angiography (CAG) were enrolled. TAGs of 309 major epicardial coronary arteries were measured. The impact of plaque composition, Agatston scores, and lesion length ratio on TAG were analyzed. Diagnostic performance vs. CAG of TAG, CCTA, and combined TAG/CCTA were evaluated, and incremental value of TAG for reclassification of CCTA stenosis severity in calcified lesions was also analyzed.

RESULTS

TAG decreased consistently with stenosis severity. TAG was significantly lower in coronary arteries with calcification scores >300 and lesion length ratios >2/3. TAG improved diagnostic accuracy of CCTA (c-statistic =0.982 vs. 0.942, P = 0.0001) in calcified lesions, and the sensitivity, specificity, positive, and negative predictive values of TAG cutoff ≤ -11.33 were 72 %, 91 %, 88 %, and 78 %, respectively. The addition of TAG to CCTA resulted in significant reclassification (NRI =0.093, P = 0.022) in calcified vessels.

CONCLUSIONS

Measurement of TAG may improve diagnostic performance and reclassification of CCTA in coronary stenosis caused by calcified lesions.

KEY POINTS

• TAG decreased as calcification scores and lesion length increased. • TAG markedly improved the diagnostic performance of CCTA for calcified lesions. • TAG improved reclassification of coronary artery stenosis severity in CCTA.

Frequency of unrecognized, unreported, or underreported coronary artery and cardiovascular calcification on noncardiac chest CT

BACKGROUND

Coronary artery calcification (CAC) is correlated with cardiovascular outcomes and, therefore, can change management. Such calcifications are identifiable on noncardiac chest CT (NCCT), although there is no standard for interpretation. However, no data are published on the frequency of these findings being reported during NCCT interpretation.

METHODS

To obtain population with a high likelihood of CAC, we identified 355 patients with known (n = 136) or suspected (n = 219) coronary artery disease in whom single-photon emission CT myocardial perfusion imaging and NCCT were ordered within 1 month of each other; their mean age was 63 years, and 204 were women. Single-photon emission CT reports, NCCT reports, and retrospective NCCT image interpretations were performed by the investigators independently.

RESULTS

CAC was present in 207 of the 355 patients (58% of the group) but was recorded in the final radiology report as present in only 44% of these subjects. CAC in the left main coronary artery was evident on review in 139 patients but was specified in the final report in only 1 patient. Left anterior descending CAC was evident in 188 patients but reported in only 3%.

CONCLUSIONS

In this observational study, CAC on NCCT in this enriched population was often unreported. Although NCCT can indicate presence and location of CAC, these features are rarely reported, even when involving locations such as the left main coronary artery or left anterior descending artery. In view of its diagnostic and prognostic importance, evaluation of CAC should become a routine part of the interpretation of NCCT.

Noninvasive anatomical coronary artery imaging versus myocardial perfusion imaging: which confers superior diagnostic and prognostic information?

Myocardial perfusion imaging (MPI) has been a valuable diagnostic and prognosticating tool for decades, but recently it has been challenged by the growing evidence about either comparable or superior diagnostic and prognostic value of computed tomography (CT)-based anatomical imaging modalities. Although there are some studies suggesting synergy and potential for combined use of these modalities to better diagnose coronary artery disease (CAD), it is important to evaluate these approaches separately, given cost and other restraints. This review compares the noninvasive anatomical imaging modalities of coronary artery calcium scoring and coronary CT angiography to the functional assessment modality of MPI in the diagnosis and prognostication of significant CAD in symptomatic patients. A large number of studies investigating this subject are analyzed with a critical look on the evidence, underlying the strengths and limitations. Although the overall findings of the presented studies are favoring the use of CT-based anatomical imaging modalities over MPI in the diagnosis and prognosticating of CAD, the lack of a high number of large- scale, multicenter randomized controlled studies limits the generalizability of this early evidence. Further studies comparing the short- and long-term clinical outcomes and cost-effectiveness of these tests are required to determine their optimal role in the management of symptomatic patients with suspected CAD.

Calcification in atherosclerosis

Coronary calcification has long been known to occur as a part of the atherosclerotic process, although whether it is a marker of plaque stability or instability is still a topic of considerable debate. Coronary calcification is an active process resembling bone formation within the vessel wall and, with the advances in CT technology of the past decade, can be easily quantified and expressed as a coronary artery calcium (CAC) score. The extent of calcium is thought to reflect the total coronary atherosclerotic burden, which has generated interest in using CAC as a marker of risk of cardiovascular events. The current consensus is that large amounts of CAC identify a highly vulnerable patient rather than a vulnerable plaque or vulnerable vessel. Indeed, CAC has incremental prognostic value beyond traditional risk factors in various subsets of the population. Furthermore, whereas the presence of CAC is associated with increased risk, a zero CAC score predicts excellent short-term to mid-term prognosis, even in high-risk patients. The advent of CT angiography has perhaps clouded the importance of CAC as a long-term marker of risk, as opposed to the presence of luminal stenoses that are associated with a more immediate risk of events.

The predictive value of computed tomography calcium scores: a comparison with quantitative volumetric intravascular ultrasound

OBJECTIVE

To evaluate the relationship between coronary artery calcium scoring (CACS) and intravascular ultrasound (IVUS) calcification and disease severity.

METHODS

Forty-five angina patients who underwent CACS 18+/-23 days before IVUS were studied. The CACS was recorded for each lesion matched to a specific IVUS lesion. Cross-sectional area measurements of the external elastic membrane, lumen area, plaque and media, and plaque burden were performed. The arc and length of calcification were measured.

RESULTS

There were 106 calcified lesions detected by IVUS. Eighty-five of those lesions (80%) were detected by CACS, but 21 calcified lesions (20%) were missed. Fourteen (50%) out of 28 of the lesions with an IVUS-calcium arc below the 25th percentile (51.4 degrees ) were detected by CACS vs. 91% of lesions with an IVUS-calcium arc >51.4 degrees (P<.05). Similarly, 21 (58%) of 36 lesions <or=3 mm in length were detected vs. 91% of lesions >3 mm (P<.05). We divided IVUS-calcified lesions into CACS <or=10 and >10. Mean plaque burden, calcified length, and arc of calcium increased significantly, while minimum lumen area decreased with increasing CACS. There was the same tendency in culprit and nonculprit calcified lesions, respectively. Multivariate analysis showed a calcified length (regression coefficient=8.718, 95% CI 4.668-12.77, P<.001) and an arc of calcium (regression coefficient=2.789, 95% CI 1.419-4.119, P<.001) were significant predictors for CACS.

CONCLUSIONS

This study suggests that a CACS could evaluate coronary calcium burden noninvasively through the accurate estimation of calcium-arc and length.

Head-to-head comparison of dobutamine stress echocardiography and cardiac computed tomography for the detection of significant coronary artery disease

OBJECTIVES

Dobutamine stress echocardiography (DSE) and contrast-enhanced electron beam tomography (EBCT) both have the potential to noninvasively detect coronary artery disease (CAD). We compared the accuracy of both methods to detect significant CAD in a direct comparison.

METHODS

79 patients (32 women, 47 men, mean age 62 years) who were admitted for coronary angiography due to suspected CAD were studied. By EBCT coronary calcification (CAC) as well as angiography (CTA) was assessed. Presence of significant CAD was assumed if the calcium score exceeded 400 or the contrast-enhanced images displayed significant lumen reduction. DSE was performed using a standard protocol (5-40 microg/kg/min dobutamine plus 0.25-1.0 mg atropine if necessary). DSE and EBCT were independently evaluated concerning the presence of significant CAD. Results were compared to invasive, quantitative coronary angiography.

RESULTS

6 patients (8%) in DSE and 2 patients (3%) in EBCT were unevaluable for various reasons and therefore excluded from further analysis. In the remaining 71 patients, 33 patients (46%) showed significant CAD. DSE demonstrated a sensitivity of 70% (23/33) and a specificity of 84% (32/38). EBCT showed a sensitivity of 91% (30/33) and a specificity of 74% (28/38). By combining DSE and EBCT sensitivity increased to 97% with a specificity of 63%.

CONCLUSIONS

In a blinded comparison, DSE demonstrated lower sensitivity but higher specificity than EBCT for the detection of significant CAD. Sensitivity was improved by combining both modalities.

Measurement of coronary calcium scores by electron beam computed tomography or exercise testing as initial diagnostic tool in low-risk patients with suspected coronary artery disease

We determined the efficiency of a screening protocol based on coronary calcium scores (CCS) compared with exercise testing in patients with suspected coronary artery disease (CAD), a normal ECG and troponin levels. Three-hundred-and-four patients were enrolled in a screening protocol including CCS by electron beam computed tomography (Agatston score), and exercise testing. Decision-making was based on CCS. When CCS>or=400, coronary angiography (CAG) was recommended. When CCS<10, patients were discharged. Exercise tests were graded as positive, negative or nondiagnostic. The combined endpoint was defined as coronary event or obstructive CAD at CAG. During 12+/-4 months, CCS>or=400, 10-399 and <10 were found in 42, 103 and 159 patients and the combined endpoint occurred in 24 (57%), 14 (14%) and 0 patients (0%), respectively. In 22 patients (7%), myocardial perfusion scintigraphy was performed instead of exercise testing due to the inability to perform an exercise test. A positive, nondiagnostic and negative exercise test result was found in 37, 76 and 191 patients, and the combined endpoint occurred in 11 (30%), 15 (20%) and 12 patients (6%), respectively. Receiver-operator characteristics analysis showed that the area under the curve of 0.89 (95% CI: 0.85-0.93) for CCS was superior to 0.69 (95% CI: 0.61-0.78) for exercise testing (P<0.0001). In conclusion, measurement of CCS is an appropriate initial screening test in a well-defined low-risk population with suspected CAD.

Cardiac CT angiography (CTA) and nuclear myocardial perfusion imaging (MPI)-a comparison in detecting significant coronary artery disease

RATIONALE AND OBJECTIVES

Endowed with sufficient diagnostic accuracy, electron beam computed tomography angiography (CTA) is being increasingly used to evaluate coronary arteries. However, data on direct comparisons with nuclear myocardial perfusion studies are limited. In this study, we sought to compare the accuracies of CTA and myocardial perfusion imaging (MPI) for identifying symptomatic patients with hemodynamically significant obstructive coronary artery disease (CAD).

MATERIALS AND METHODS

In a single-center study, symptomatic outpatients who were scheduled for cardiac catheterization were prospectively enrolled. Only patients with exertional angina or dyspnea were included. After fulfilling the inclusion criteria, 30 patients were enrolled in the study (mean age 54 +/- 9 years and 70% males). Patients underwent MPI, CTA including coronary artery calcification (CAC) measure, and invasive coronary angiography for evaluation of obstructive coronary artery disease. Significant CAD was defined as >50% left main artery stenosis or >70% stenosis of any other epicardial vessel by invasive angiography. The sensitivities, specificities and predictive values of MPI, CAC, and CTA were analyzed per patient

RESULTS

CTA demonstrated significant higher sensitivity than MPI (95% vs. 81%, P < .05). CTA demonstrated significantly higher specificity than both MPI (89% versus 78%, P = .04) and CAC (56%, P = .002). CTA also performed better in a per-vessel analysis (sensitivity 94%, specificity 96%) than both nuclear and CAC. There were no significant differences between the sensitivities and specificities of MPI and CAC.

CONCLUSION

CTA accurately detects obstructive CAD in symptomatic patients and may be more accurate than MPI or CAC assessment. Larger studies in a more diverse population are needed.

Cardiovascular calcifications after radiation therapy for Hodgkin lymphoma: computed tomography detection and clinical correlation

OBJECTIVE

To study cardiovascular calcifications, detected by computed tomography, in patients following mediastinal radiation for Hodgkin lymphoma, and correlate them with clinical findings.

MATERIALS AND METHODS

Fifteen patients, <or=55 years, with computed tomography detected cardiovascular calcifications after mediastinal radiotherapy for Hodgkin lymphoma were identified during a 10-year period. Calcifications were evaluated for site and extent and were correlated with clinical data including symptoms and signs of heart disease, angiographic and surgical findings.

RESULTS

Accelerated calcifications were detected in the coronary arteries (n=11), in the aorta (n=11), and in the aortic valve and the mitral apparatus (n=8). Calcifications were more extensive when radiation was given at a young age. Clinical evidence of cardiovascular disease included coronary events in three patients, valvular dysfunction in two, pericarditis in two and complete atrioventricular block in one. Seven patients had no cardiac symptoms.

CONCLUSION

Early cardiovascular calcifications can be radiation associated. Such calcifications may represent radiation-induced atherosclerosis and can be detected by computed tomography even in asymptomatic patients. The implication of our findings is that spiral computed tomography may serve as a non-invasive modality to detect accelerated cardiovascular calcifications in high-risk asymptomatic patients who survived Hodgkin lymphoma.

Computed tomography calcium quantification as a measure of atherosclerotic plaque morphology and stability

OBJECTIVES

We examined the relationship between computed tomography (CT)-quantified calcium and histopathologic atherosclerotic plaque morphology and rupture.

MATERIALS AND METHODS

Seven aortae were harvested from autopsy cases. All were scanned, ex vivo, on a 16-slice CT scanner and CT calcium scores (CTCS) were calculated using a Siemens Calcium Scoring package. The aorta segments were physically cross sectioned at 3-mm intervals corresponding to CT reconstructions. Two pathologists evaluated the cross sections for histology calcium score (HCS), plaque fibrous cap disruption, overlying thrombus, internal hemorrhage, size, lipid content, and inflammation. CT and histology data were subsequently paired using predetermined quadrant and slice conventions.

RESULTS

Three hundred forty-nine aorta cross sections yielded 41 atherosclerotic plaques. Eleven plaques demonstrated plaque disruption and thrombosis and all contained calcium. CTCS was not significantly different between atherosclerotic plaques with and without evidence of disruption/thrombosis (F[1,30] = 1.525, P = 0.227). CT was 100% sensitive for nodular calcification, but only 56% (5 of 9 plaques) sensitive for non-nodular calcification. There was no significant relationship between CTCS and intraplaque hemorrhage, lipid content, inflammation, and plaque size (P = 0.179, P = 0.230, P = 0.314, and P = 0.054). There was significant correlation between CTCS and HCS (Pearson coefficient = 0.535; P < 0.01).

CONCLUSIONS

Calcium quantity does not appear to predict plaque morphology or likelihood of rupture. CT has lower sensitivity for non-nodular compared with nodular calcification.

Evaluation of coronary arterial stenoses using 2D magnetic resonance coronary angiography

This study investigated the usefulness and limitations of magnetic resonance coronary angiography (MRCA). MRCA was performed with an electrocardiographically gated gradient echo sequence with k-space segmentation. Coronary angiography (CAG) was performed using a conventional system. We had three protocols. In protocol one, 160 consecutive patients (279 coronary arteries) who underwent initial CAG for diagnosing coronary artery disease were enrolled. Out of the 279 coronary arteries, 235 arteries (84.2%) were visualised with an image quality suitable for further analysis. In these 235 arteries, the validity for diagnosing over 75% arterial stenosis was 98%, and sensitivity and specificity was 79%. In protocol two, 48 stenoses were evaluated for restenosis after balloon angioplasty. The validity for diagnosing restenosis by MRCA was 93% in sensitivity and 33% in specificity. In protocol three, comprising 18 coronary arteries with total obstruction, the presence of collaterals was evaluated. The development of collateral circulation improved MRCA findings in the distal portion of obstructed coronary arteries. We conclude that MRCA provides useful information with acceptable sensitivity and specificity before balloon angioplasty. However, MRCA has a tendency to over-estimate restenosis after balloon angioplasty.

Coronary calcium scanning

While there is no doubt that high-risk patients (those with more than a 20% 10-year risk of a future cardiovascular event) need more aggressive preventive therapy, a majority of cardiovascular events occur in individuals at intermediate risk (10%-20% 10-year risk). Data suggest that it will be most cost-effective to concentrate screening efforts on this group of patients. Coronary artery calcium has been shown to be highly specific for atherosclerosis, occurring only in the intima of the coronary arteries. There is evidence to show that elevated coronary calcium scores are predictive of cardiovascular events, both independently of and incrementally to conventional cardiovascular risk factors. Based on current available data, patients with increased plaque burdens (increased coronary calcium scores) are approximately 10 times more likely to suffer a cardiac event over the next 3-5 years. Coronary calcium scores have outperformed conventional risk factors, high sensitivity C-reactive protein, and carotid intima-media thickness as a predictor of cardiovascular events. Both electron beam tomography and multidetector computed tomography can accurately detect and quantify the coronary calcium scores. In summary, coronary calcium detection significantly improves the accuracy of global cardiovascular risk prevention, the noninvasive tracking of the atherosclerotic burden, and the prediction of cardiovascular events.

Comparison of coronary calcium and stress myocardial perfusion imaging in apparently healthy siblings of individuals with premature coronary artery disease

Detection of subclinical coronary atherosclerosis is possible using exercise myocardial perfusion imaging for inducible ischemia or multidetector computed tomography for coronary artery calcium (CAC), which is used to detect subclinical coronary atherosclerosis. The extent to which these screening tests converge in an asymptomatic population that is at increased risk for coronary artery disease remains unknown. We compared the concordance of findings in 260 asymptomatic middle-age siblings of hospitalized index patients <60 years of age with documented coronary artery disease. All subjects underwent maximal exercise testing with postexercise and delayed attenuation-corrected thallium single-photon emission computed tomography and multidetector computed tomography for CAC. An abnormal exercise single-photon emission computed tomographic (SPECT) result occurred in >50% of subjects with a CAC score >100, but also in 12% with no CAC, 9% with CAC scores of 1 to 10, and 20% with CAC scores of 11 to 100. In subjects with an abnormal exercise SPECT result, 59% had CAC scores < or =100. Overall, there was only a modest agreement between an abnormal exercise SPECT result and high CAC scores. In conclusion, although moderate or severe CAC is often associated with inducible ischemia, the absence of CAC or the presence of only mild CAC by no means precludes inducible myocardial ischemia. These screening tests may reflect different aspects or stages of coronary disease in an asymptomatic middle-age population.

Computed Tomographic Cardiovascular Imaging

Over the last decade, there has been increased recognition that atherosclerosis imaging adds greatly to the ability to identify patients at high risk for cardiac events. Technologies such as electron beam computed tomography and carotid intimal media thickness have contributed significantly to our understanding of the prevalence of preclinical atherosclerosis and its consequences. Current data suggest that elevated calcium scores are predictive of future cardiac events, independently and incrementally to traditional cardiac risk factors. The approximate predictive power is 10-fold for scores > 100, based upon current studies now reported. Guidelines and policy toward these modalities have shifted, with increased recognition of the importance among experts in cardiology, lipidology, and preventive medicine. Because most adverse events related to atherosclerosis occur in individuals at an intermediate risk, data suggest that it will be most cost-effective to concentrate screening efforts on this group of patients. This article reviews the current understanding of the value of coronary artery calcium screening in asymptomatic and symptomatic patients. Accurate measurement of subclinical coronary atherosclerosis should significantly improve the accuracy of global cardiovascular risk prediction, and allow for tracking of atherosclerosis burden, as well as better prediction of future cardiovascular events. Finally, by identifying high-risk patients, CAC may help select those patients who would benefit most from additional testing (e.g., non-invasive stress imaging) and intensification of medical therapy; CAC should have a significant impact on early detection and management of CAD.

Clinical Significance of the Coronary Calcification Score by Multidetector Row Computed Tomography for the Evaluation of Coronary Stenosis in Japanese Patients

BACKGROUND

The coronary artery calcification (CAC) score measured by multidetector row computed tomography (MDCT) has emerged as a marker for predicting coronary artery disease (CAD). To evaluate the clinical significance of the CAC score, coronary artery stenosis as assessed by coronary angiography (CAG) was compared with the CAC score determined by MDCT, risk factors and medications.

METHODS AND RESULTS

Subjects included 374 consecutive patients who underwent ECG-gate CT angiography using MDCT. The accuracy in patients with a CAC score >or=400 was 84%, and significantly lower than that in patients with a CAC score =0. In addition 92 patients (68 males, 24 females; mean age, 63+/-11 years) who underwent both MDCT and CAG within a 1-month period were selected for further investigation. Patients with significant coronary stenosis had a significantly higher CAC score than those without stenosis. In addition, a higher number of stenosed vessels was associated with a higher CAC score. The subjects were divided into 3 groups according to the CAC score: low (0-12), intermediate (13-444) and high (>or=445). The CAC score was significantly associated with age, and plasma levels of total cholesterol and hemoglobinA1c, and logistic regression analysis revealed that significant coronary stenosis as assessed by CAG was most closely correlated with the CAC score (p=0.03).

CONCLUSIONS

The CAC score determined by MDCT can predict CAD independent of other factors, such as age, metabolic diseases and medications, when coronary stenosis can not be diagnosed because of severe calcification.

The relationship between coronary artery calcification detected by non-gated multi-detector CT in patients with suspected ischemic heart disease and myocardial ischemia detected by thallium exercise stress testing

OBJECTIVE

To examine whether we could predict myocardial ischemia when coronary artery calcification is detected by non-gated multidetector CT in patients with suspected ischemic heart disease.

METHODS

Eighty-three patients suspected of having ischemic heart disease (55 men, 28 women; age range 36-83 years; mean age 68 years) underwent multidetector CT and T1-201 single photon emission computed tomography. Prediction of myocardial ischemia by coronary arterial calcification detected on CT was evaluated by comparing the coronary artery territories that showed calcification with the area of myocardial ischemia determined by SPECT. The sensitivity, specificity, positive predictive value, and negative predictive value of multidetector CT for predicting myocardial ischemia were calculated. Coronary angiography was also examined and compared with multidetector CT. Risk factors, including hypertension, smoking, hyperlipidemia, diabetes, and family history, were compared for evidence of coronary artery calcification detected by multidetector CT and myocardial ischemia detected by thallium nuclear scans.

RESULTS

For analysis by patients, the sensitivity, specificity, positive predictive value, and negative predictive value of coronary artery calcification for myocardial ischemia detection were 65, 63, 56, and 71%, respectively. Similarly, for analysis by coronary arterial territories, those values were 56, 77, 41 and 86%, respectively. Coronary stenosis on CAG was also related to the ischemia determined by SPECT and calcification on multidetector CT. Ischemia was better influenced by risk factors than was coronary arterial calcification.

CONCLUSIONS

For analysis by coronary arterial territories, the specificity and negative predictive value of coronary arterial calcification seen by multidetector CT are relatively high.

Abnormal peripheral circulation in type 2 diabetic patients with normal ankle-brachial index associates with coronary atherosclerosis, large artery stiffness, and peripheral vascular resistance

We tested the hypothesis that impaired peripheral circulation in diabetes arises from different aspects of vascular abnormalities even when accompanied by a normal ankle-brachial index (ABI>0.9). One hundred fourteen type 2 diabetic patients with normal ABI and 33 age-matched non-diabetic subjects consecutively admitted to our hospital were enrolled. The Agatston coronary artery calcium score (CACS), as a marker of coronary atherosclerosis, was obtained using electron-beam computed tomography. An automatic device was used to measure brachial-ankle pulse wave velocity (baPWV) as an index of arterial distensibility. Total flow volume and resistive index (RI), as a marker of peripheral vascular resistance, at the popliteal artery were evaluated using gated two-dimensional cine-mode phase-contrast magnetic resonance imaging. Diabetic patients had baPWV (P<0.001) and RI (P<0.001) higher than those in the non-diabetic subjects, indicating that those parameters are characteristically altered in diabetic patients. When diabetic patients were grouped into three subgroups according to their levels of total flow volume, those with the lowest range showed the highest log-transformed CACS (P<0.001), baPWV (P<0.001), and RI (P<0.001) among the groups. Total flow volume was negatively correlated with log-transformed CACS (P<0.001), baPWV (P<0.001), and RI (P<0.001). Waveform at the popliteal artery could be clearly separated into systolic and early and late diastolic blood flows, which were negatively correlated with log-transformed CACS (P<0.001), RI (P<0.001), and baPWV (P<0.001), respectively. These results suggest that impaired peripheral circulation in diabetes is attributable to coronary atherosclerosis, large artery stiffness, and peripheral vascular resistance even when ABI is normal.

Evaluation of coronary artery calcification by multi-detector row computed tomography for the detection of coronary artery stenosis in Japanese patients

BACKGROUND

The development of an efficient noninvasive examination to detect coronary atherosclerosis is needed as a strategy to prevent coronary heart disease. To evaluate the usefulness of calcium score measured by multi-detector row computed tomography (MDCT), we compared calcium score derived from MDCT with findings of coronary artery stenosis assessed by coronary angiography (CAG).

METHODS

In 108 patients (94 men, 14 women; average age, 65.7 years), we performed unenhanced CT scans and calculated coronary artery calcium score in 259 vessels without previous intervention and severe motion artifact to determine the correlation with the degree of coronary stenosis by CAG.

RESULTS

The sensitivity and the specificity of calcification (calcium score 0.1+) for severe stenosis (75+%) were 89% and 43%, respectively. All four vessels with calcium score 1000+ had a severe stenosis. The areas under the receiver operating characteristics curve of calcium score for severe stenosis were 0.80 +/- 0.04, indicating the efficacy of this technique.

CONCLUSIONS

Coronary artery calcification and calcium score determined by MDCT were associated with coronary arteries with severe stenosis. This technique appears to be useful for the evaluation of coronary atherosclerosis.

Comparison of Electron Beam Computed Tomography and Technetium Stress Testing in Differentiating Cause of Dilated Versus Ischemic Cardiomyopathy

OBJECTIVE

The current reference standard for differentiating between nonischemic versus ischemic cardiomyopathy (CM) is angiography. The diagnostic accuracy of nuclear stress testing and electron beam tomography (EBT) was evaluated to differentiate between nonischemic and ischemic CM, using coronary angiography as the reference standard.

METHODS

A total of 56 patients who underwent technetium stress testing and coronary angiography for the evaluation of CM were enrolled. Patients then underwent EBT coronary scanning for coronary calcification (CC).

RESULTS

Of the 56 patients, 34 (61%) had angiographically significant disease. Using the criteria of ischemia (reversible defect) or infarct (fixed defect) to define a patient with ischemic CM, nuclear stress testing had a sensitivity of 97% (33 of 34 patients) but a specificity of only 18% (4 of 22 patients). Using the criteria of reversible ischemia only, the specificity of nuclear stress testing improved to 50% (P < 0.001); however, the sensitivity decreased to 56%. An EBT score >0 had a sensitivity of 97% (33 of 34 patients) and a specificity of 68% (15 of 22 patients) for defining ischemia. Overall diagnostic accuracy was significantly higher with EBT as compared with nuclear stress testing in this study of patients with reduced ejection fractions (84% vs. 64%; P = 0.009).

CONCLUSION

Given the high sensitivity of nuclear testing and EBT, these tests may prove to be an effective screen before angiography in patients with congestive heart failure of unclear cause.

Update on using coronary calcium screening by computed tomography to measure risk for coronary heart disease

Coronary artery disease (CAD) is the number one killer of adults in the United States, claiming one-half million deaths annually. Early detection and prevention strategies clearly remain a top priority for health care providers in order to reduce the high mortality rate of heart disease. As an unequivocal reflection of arteriosclerosis, coronary arterial calcium (CAC) may provide a means to qualitatively assess the overall disease severity and likewise serve as a means to assess risk for CHD. It is known that patients with heavy calcium burdens have more advanced CAD, a concomitantly a higher likelihood of coronary stenoses, and a concomitant higher risk for acute cardiac events. Computed tomography has been shown to be an accurate, non-invasive method to quantify coronary calcification burden in patients. Evidence shows that calcium measurements by CT correlate well with histological plaque analyses, and that CAC measurements accurately reflect disease severity and can be useful to assess individual risk for CHD. The purpose of this article is to summarize the currently available evidence that has attempted to validate CAC screening as a screening exam and risk predictor for coronary heart disease.

Virtopsy: postmortem imaging of the human heart in situ using MSCT and MRI

The rapid further development of computed tomography (CT) and magnetic resonance imaging (MRI) induced the idea to use these techniques for postmortem documentation of forensic findings. Until now, only a few institutes of forensic medicine have acquired experience in postmortem cross-sectional imaging. Protocols, image interpretation and visualization have to be adapted to the postmortem conditions. Especially, postmortem alterations, such as putrefaction and livores, different temperature of the corpse and the loss of the circulation are a challenge for the imaging process and interpretation. Advantages of postmortem imaging are the higher exposure and resolution available in CT when there is no concern for biologic effects of ionizing radiation, and the lack of cardiac motion artifacts during scanning. CT and MRI may become useful tools for postmortem documentation in forensic medicine. In Bern, 80 human corpses underwent postmortem imaging by CT and MRI prior to traditional autopsy until the month of August 2003. Here, we describe the imaging appearance of postmortem alterations--internal livores, putrefaction, postmortem clotting--and distinguish them from the forensic findings of the heart, such as calcification, endocarditis, myocardial infarction, myocardial scarring, injury and other morphological alterations.

Relationship between stress-induced myocardial ischemia and atherosclerosis measured by coronary calcium tomography

OBJECTIVES

We assessed the relationship between stress-induced myocardial ischemia on myocardial perfusion single-photon emission computed tomography (MPS) and magnitude of coronary artery calcification (CAC) by X-ray tomography in patients undergoing both tests.

BACKGROUND

There has been little evaluation regarding the relationship between CAC and inducible ischemia or parameters that might modify this relationship.

METHODS

A total of 1,195 patients without known coronary disease, 51% asymptomatic, underwent stress MPS and CAC tomography within 7.2 +/- 44.8 days. The frequency of ischemia by MPS was compared to the magnitude of CAC abnormality.

RESULTS

Among 76 patients with ischemic MPS, the CAC scores were >0 in 95%, >or=100 in 88%, and >or=400 in 68%. Of 1,119 normal MPS patients, CAC scores were >0, >or=100, and >or=400 in 78%, 56%, and 31%, respectively. The frequency of ischemic MPS was <2% with CAC scores <100 and increased progressively with CAC >or=100 (p for trend <0.0001). Patients with symptoms with CAC scores >or=400 had increased likelihood of MPS ischemia versus those without symptoms (p = 0.025). Absolute rather than percentile CAC score was the most potent predictor of MPS ischemia by multivariable analysis. Importantly, 56% of patients with normal MPS had CAC scores >or=100.

CONCLUSIONS

Ischemic MPS is associated with a high likelihood of subclinical atherosclerosis by CAC, but is rarely seen for CAC scores <100. In most patients, low CAC scores appear to obviate the need for subsequent noninvasive testing. Normal MPS patients, however, frequently have extensive atherosclerosis by CAC criteria. These findings imply a potential role for applying CAC screening after MPS among patients manifesting normal MPS.

Coronary Artery Calcification Scoring by Prospectively Triggered Multidetector-Row Computed Tomography

The objective of this study was to measure the interobserver and interscan variation of coronary artery calcium scores using multidetector-row computed tomography (MDCT). Seventy-five patients underwent 2 sequential MDCT scans for coronary artery calcification. Each patient's score was separately measured by 3-blinded radiologists. Scores were treated as discrete and continuous data, and independent statistical analysis was performed on all results. There was a high proportion of interscan and inter-reader concordance for the presence of coronary calcium (range, 0.893-0.973) and for its quantity (range, 0.936-0.988). Overall, prospectively triggered multidetector-row calcium scoring is reproducible though there is more variation in those patients with already high scores. There is no need to scan patients twice at the same sitting.

Imaging of coronary calcification by computed tomography

As an unequivocal biomarker for arteriosclerosis, the presence of coronary calcium serves as a qualitative reflection of the severity of coronary artery disease (CAD). Greater calcium burdens correlate with more advanced disease, a higher likelihood of coronary stenoses, and a higher risk for coronary heart disease (CHD). Empirically, the quantification of coronary calcium not only provides an accurate reflection of disease severity, but also has great potential as a screening tool for CHD. Computed tomography (CT) has been shown to be capable of providing accurate, noninvasive measurements of coronary calcification. Evidence shows that calcium measurements by CT correlate well with histological plaque analyses, and that calcium burdens accurately reflect disease severity and can be used to assess individual risk for CHD. The purpose of this review article is to examine the accumulated evidence that has attempted to validate CT as a diagnostic tool for CAD and as a screening exam for CHD.

Coronary artery calcium and its relationship to coronary artery disease

Electron-beam computed tomography (EBCT) and the recent generation of multi-slice computed tomography scanners (MSCT) permit high-resolution imaging of the beating heart and the coronary arteries. The visualization of coronary calcium offers the opportunity to non-invasively obtain direct information on coronary anatomy and plaque burden. For clinical purposes, coronary calcium represents the presence of arteriosclerotic plaques. Coronary calcium is deposited in an actively regulated process related to lipid content of and apoptosis within coronary plaques. The amount of coronary calcium is related to the extent of coronary plaque disease, which has substantial diagnostic and prognostic implications. Visualization of coronary calcium by cardiac CT allows to non-invasively detect and localize coronary plaques and describe their distribution in the coronary tree. Approximately 50% to 70% of all plaques are calcified. Calcium cannot be used to reliably identify plaques at risk for developing complications such as rupture or erosion with ensuing thrombus formation. However, data are accumulating that indicate that calcium is an indicator of coronary arteriosclerotic disease activity. A scan negative for coronary calcium has a high negative predictive value indicating absence of stenotic coronary artery disease and an excellent short- to mid-term prognosis. Studies using serial CT scans indicate that the annual progression of coronary calcium varies between 30% to 50% in symptomatic or high-risk individuals and 0% to 20% in patients treated effectively with lipid-lowering medication. An increased rate of progression of coronary calcium seems to indicate a substantially increased risk for adverse cardiac events.

Cardiac anxiety in patients self-referred for electron beam tomography

Studies have repeatedly shown that as many as 43% of patients undergoing coronary angiograms have no evidence of coronary heart disease (CHD). Fear of cardiac-related sensations has been posited as one explanation for complaints of chest pain in patients without CHD. The purpose of this study is to examine variables associated with cardiac anxiety in a sample of individuals self-referred for noninvasive coronary calcium screening. Nearly one quarter of the subjects screened experienced chest pain in the absence of coronary artery calcium (CAC). Individuals without evidence of CAC were more likely to report higher levels of heart-focused attention, even when subjects with any risk factors for CHD were excluded from the analyses. Men were more likely to have evidence of coronary calcium, although a greater proportion of women reported chest pain. Women generally endorsed higher levels of cardioprotective behavior, heart-focused attention, and fear of heart-related sensations. Findings are discussed in relation to treatment of cardiac anxiety and the prevention of unnecessary medical procedures.

Coronary calcium detected by digital cinefluoroscopy and coronary artery disease in patients undergoing coronary arteriography: effects of age and sex

BACKGROUND

Coronary artery calcium, detected non-invasively, correlates well with angiographically documented coronary artery disease (CAD). This study was conducted to evaluate the diagnostic efficacy of coronary artery calcium detected by digital cinefluoroscopy for CAD and assess the effects of age and sex on it.

METHODS

In 242 patients who underwent coronary angiography, coronary calcium status was determined and related to angiographic findings.

RESULTS

Calcium detection had a sensitivity 85%, specificity 52%, positive predictive value 92%, negative predictive value 33% and diagnostic accuracy 81% for significant CAD. There was a better positive predictive value in men (95% vs. 80%) and negative predictive value in women (65% vs. 16%), while a higher sensitivity and diagnostic accuracy was found in older than in younger (90% and 86% vs. 78% and 74%). The sensitivity of the method increased with the number of the diseased vessels.

CONCLUSIONS

Coronary calcium can be quite accurately detected by digital cinefluoroscopy. This, however, should be made in the context of sex and age.

Coronary artery calcium measurement with multi-detector row CT: in vitro assessment of effect of radiation dose

The authors assessed in vitro the effect of radiation dose on coronary artery calcium quantification with multi-detector row computed tomography. A cardiac phantom with calcified cylinders was scanned at various milliampere second settings (20-160 mAs). A clear tendency was found for image noise to decrease as tube current increased (P <.001). No tendency was found for the Agatson score or calcium volume and mass errors to vary with tube current. Calcium measurements were not significantly affected by the choice of tube current. Calcium mass error was strongly correlated with calcium volume error (P <.001). The calcium mass measurement was more accurate and less variable than the calcium volume measurement.

Beyond traditional risk factor analysis for coronary artery disease: the case for coronary artery calcium assessment with electron beam computed tomography

Coronary artery disease is often asymptomatic, leading to inefficient detection. Although coronary artery disease is associated with multiple risk factors, better methods for detection are needed. The quantity of coronary artery calcium as detected with electron beam computed tomography is indicative of plaque mass, and the likelihood of coronary obstruction and future coronary events is independent of other risk factors. Screening for coronary artery disease with electron beam computed tomography offers a complimentary way of detecting early atherosclerosis in asymptomatic patients.

A review of electron beam computed tomography: implications for coronary artery disease screening

Coronary artery disease is the leading cause of death in the United States, thus the intense interest in a screening test that would allow early identification of coronary artery disease in its asymptomatic stage, allowing early aggressive targeted risk factor reduction. While office-based risk factor assessment is currently the reference standard for prediction of cardiac risk, several imaging tests are currently being investigated. Electron beam computed tomography (EBCT) can accurately identify calcium in the coronary tree noninvasively. Coronary calcium is clearly linked with coronary atherosclerosis. In population studies, populations with higher calcium scores have more calcium events. The predictive value of a calcium score for an individual is currently under investigation, as well as the incremental value of a calcium score over office-based risk assessment in cardiac risk prediction. This review looks at the current role of EBCT in the prevention of cardiovascular disease. It summarizes the current data for calcium as a screening tool, which is strongest in establishing that asymptomatic people undergo increased rates of revascularization after an EBCT test. Widespread clinical use of EBCT is not recommended, pending data to establish its efficacy in the role of risk factor reduction and prevention of cardiovascular disease.

Electron beam tomography and angiography: sex differences

BACKGROUND

We sought to study a large cohort of symptomatic women to determine the clinical use of electron beam tomography (EBT), with evaluation of the sensitivity and specificity of obstructive coronary disease and the differences between premenopausal and postmenopausal cohorts.

METHODS

Patients who underwent angiography for evaluation of coronary artery disease (CAD) and EBT within 3 months were enrolled. Receiver operating characteristic curves were used to establish relationships between EBT calcium scores and angiographic disease.

RESULTS

We studied 1120 symptomatic patients, 387 women and 733 men. We found no significant differences with respect to sensitivity for obstructive disease (96% in men and women). However, women had a significantly higher specificity (46% in men versus 57% in women; P =.01). The area under the curves for coronary calcium score predicting angiographic disease was 0.85 for all patients and 0.84 in women. Evaluation of scores on the basis of age revealed a 14.4-year lag between men and women. One hundred thirty-five women had negative EBT study results (score, zero; no calcium present), with 6 with single-vessel disease and 129 with normal coronaries or nonobstructive disease only (negative predictive value, 96%).

CONCLUSION

EBT may have a great value in evaluation of women with possible CAD. The high sensitivity and high negative predictive value may serve as the basis for a new diagnostic approach to filter symptomatic women with suspected CAD before coronary angiography.

Coronary artery calcium: absolute quantification in nonenhanced and contrast-enhanced multi-detector row CT studies

PURPOSE

(a) To determine the accuracy of multi-detector row computed tomography (CT) in the measurement of the calcium concentration in a cardiac CT calibration phantom and (b) to assess the correlation of a traditional 3-mm section width CT coronary screening protocol and a 1.25-mm section width CT angiography imaging protocol in the quantification of the absolute mass of coronary calcium in patients who underwent both coronary screening and CT angiography with a multi-detector row CT scanner.

MATERIALS AND METHODS

A heart phantom containing calcified cylinders was scanned to determine calibration factors and absolute calcium mass. In 50 patients, the variability (value 1 - value 2/mean value 1 - value 2), limit of agreement (+/-2SD value 1 - value 2), and systematic error (mean value 1 - value 2) of the total amount of coronary calcium calculated at traditional 3-mm section width CT and at 1.25-mm section width CT angiography were determined.

RESULTS

The correlation coefficient between the 3-mm section width, nonenhanced protocol and the 1.25-mm section width CT angiography protocol was very high (r = 0.977) and the mean variability was low (19.7%) for the absolute mass. There was a systematic error of -6.7 mg and a limit of agreement between 45.0 mg and -58.5 mg.

CONCLUSION

Use of the mass quantification algorithm in combination with a calibration phantom allows accurate quantification of coronary calcium. Measurements of calcium mass obtained at 1.25-mm section width CT angiography have the best agreement with those obtained at the traditional 3-mm section width imaging protocol.

Coronary calcium scanning adds incremental value to patients with positive stress tests

BACKGROUND

The sensitivity of coronary calcification by electron beam tomography (EBT) for the detection of coronary atherosclerosis is well-established. Combining the anatomic information of EBT with the functional information of stress testing might reduce the high false-positive result rate seen with treadmill stress test (TMST) alone. No studies have reported the additive value of a negative EBT result (no coronary calcium) for excluding obstructive coronary artery disease (OCAD) in patients with a positive TMST result. This study evaluated the negative predictive value and potential clinical utility of EBT to identify patients with a falsely abnormal TMST.

METHODS

A coronary calcium score was determined by EBT for 153 symptomatic patients who underwent coronary angiography because of a positive TMST. The sensitivity, specificity, and predictive values of EBT were determined. A multiple logistic regression analysis compared conventional cardiac risk factors with coronary calcification by EBT for predicting OCAD. A receiver operating characteristic curve was generated plotting sensitivity versus false-positive rate.

RESULTS

The false-positive rate of the TMST compared with angiography was 27% (41 of 153). The sensitivity of a nonzero coronary calcium score for OCAD was 98% (110 of 112), with a negative predictive value of 93%. According to multiple logistic regression, coronary calcification by EBT was a stronger predictor of OCAD than any conventional cardiac risk factor. EBT calcium added incremental value to the results of the TMST. Receiver operating characteristic curve analysis found an area under the curve of 0.91 (P <.001).

CONCLUSIONS

The absence of coronary calcification by EBT reliably identified patients with a false-positive TMST result. The combination of EBT with TMST is a potentially useful diagnostic strategy to reduce the number of false-positive test results.

Coronary benefits of calcium antagonist therapy for patients with hypertension

Calcium antagonists effective in lowering blood pressure are a heterogeneous group including three main classes: phenylalkylamines, benzothiazepines and dihydropyridines. Dihydropyridines have a dual mode of action upon the endothelium contributing to their beneficial antihypertensive effects: (1) direct relaxation by inhibition of smooth muscle L-type calcium current, and (2) indirect relaxation through release of nitric oxide from the vascular endothelium. Calcium antagonists may affect many calcium-dependent events in the formation of atherosclerosis such as the localized accumulation of collagen, elastin, and calcium together with monocyte infiltration and smooth muscle proliferation and migration. In the INSIGHT calcification study, the overall treatment effect of nifedipine demonstrated significant inhibition of coronary calcium progression over a three-year period. Calcium antagonists improve symptoms and reduce ischemia in hypertensive patients with ischemic heart disease. Although in placebo-controlled trials calcium antagonists demonstrated a significant reduction in cardiovascular morbidity and mortality, they may be less effective than other types of antihypertensive drugs in preventing ischemic heart disease.

Differential coronary calcification on electron-beam CT between syndrome X and coronary artery disease in patients with chronic stable angina pectoris

STUDY OBJECTIVES

The differential diagnosis of syndrome X and coronary artery disease (CAD) in patients with evidence of myocardial ischemia may be difficult. The possible difference in coronary calcium detected by electron-beam CT (EBCT) between syndrome X and CAD is rarely evaluated, especially in aged patients with chronic, stable angina.

DESIGN AND SETTINGS

Prospective, controlled study at a tertiary referral medical center.

PATIENTS AND MEASUREMENTS

Forty patients with syndrome X (85% male) and 53 patients with CAD (89% male) were enrolled. Ten control subjects (90% male) with negative exercise treadmill test results and normal coronary angiographic findings served as control subjects. EBCT determined the coronary calcium scores (CCSs), and standard cardiovascular risk factors of all study subjects were analyzed.

RESULTS

The 93 study patients had CCSs that ranged from 0 to 1,857. Coronary calcification was seen in 2 of the 10 control subjects (20%), 21 of the 40 syndrome X patients (52.5%), and 51 of the 53 CAD patients (96.2%) [p < 0.01]. The CCS (median [range]) was significantly lower in syndrome X patients than in CAD patients: 1 (0 to 117) vs 202 (0 to 1,857) [p < 0.001]. Receiver operating characteristic curve analyses also demonstrated that coronary calcification differentiated syndrome X from CAD (area under curve, 0.891; 95% confidence interval, 0.806 to 0.947). Of the CAD patients whose CCSs were < 117 and overlapped with CCSs of syndrome X, multivariate analyses determined CCS > 5 (odds ratio, 13.1; 95% confidence interval, 2.86 to 59.7), hypertension (odds ratio, 6.4; 95% confidence interval, 1.5 to 27.4), and hypercholesterolemia (odds ratio, 6.7; 95% confidence interval, 1.5 to 30.5) to be independent discriminators to differentiate CAD from syndrome X. Patients with CAD had more frequent hypertension than patients with syndrome X.

CONCLUSIONS

The coronary calcium detected noninvasively by EBCT was different, though with some overlapping, between patients with syndrome X and CAD. In addition to standard cardiovascular risk factors, CCS determined by EBCT (especially > 117 or = 0) could differentiate between syndrome X and CAD in patients with chronic, stable angina with evidence of myocardial ischemia. Larger trials would be useful to validate CCS on EBCT as a predictor of clinical outcome in these patients.

Calcium channel blocker nifedipine slows down progression of coronary calcification in hypertensive patients compared with diuretics

Calcium controls numerous events within the vessel wall. Permeability of the endothelium is calcium dependent, as are platelet activation and adhesion, vascular smooth muscle proliferation and migration, and synthesis of fibrous connective tissue. Double-helix computerized tomography is a noninvasive technique that can detect, measure, and compare coronary calcification in the coronary arteries. Using this method, our objective was to determine whether administration of nifedipine once daily in lieu of diuretics in high-risk hypertensive patients will arrest or slow down the progression of coronary artery calcification. The study was designed as a side arm of INSIGHT (International Nifedipine Study: Intervention as Goal for Hypertension Therapy), aimed to show the efficacy of nifedipine once daily versus co-amilozide (hydrochlorothiazide 25 mg, amiloride 2.5 mg) in high-risk hypertensive patients. A total of 201 patients with a total calcium score of >/=10 at the onset of study who underwent an annual double-helix computerized tomography for 3 years were analyzed for efficacy. Inhibition of coronary calcium progression was significant in the nifedipine versus the co-amilozide group during the first year (3.18% versus 27%, respectively, P=0.02), not significant during the second year (28.5% versus 47%, respectively, P=0.14), and significant during the third year (40% versus 78%, respectively, P=0.02). The results point to a slower progression of coronary calcification in hypertensive patients on nifedipine once daily versus co-amilozide.

Usefulness of spiral computed tomography (dual-slice mode) for the detection of coronary artery calcium in patients with chronic atypical chest pain, in typical angina pectoris, and in asymptomatic subjects with prominent atherosclerotic risk factors

The prevalence and extent of coronary calcium were retrospectively assessed by spiral computed tomography in 541 patients (mean age 62 +/- 9 years), of whom 101 had typical angina pectoris, 307 had atypical chest pain, and 133 were asymptomatic subjects with prominent atherosclerotic risk factors. The highest prevalence of coronary calcium was in men with angina pectoris (89%), whereas it was not detected in 48% of men and 56% of women with atypical chest pain.