Fast computed tomography detection of coronary calcification in the diagnosis of coronary artery disease. Comparison with angiography in patients < 50 years old

Coronary Artery Calcium Data and Reporting System (CAC-DRS): A Primer

The Coronary Artery Calcium Data and Reporting System (CAC-DRS) is a standardized reporting method for calcium scoring on computed tomography. CAC-DRS is applied on a per-patient basis and represents the total calcium score with the number of vessels involved. There are 4 risk categories ranging from CAC-DRS 0 to CAC-DRS 3. CAC-DRS also provides risk prediction and treatment recommendations for each category. The main strengths of CAC-DRS include a detailed and meaningful representation of CAC, improved communication between physicians, risk stratification, appropriate treatment recommendations, and uniform data collection, which provides a framework for education and research. The major limitations of CAC-DRS include a few missing components, an overly simple visual approach without any standard reference, and treatment recommendations lacking a basis in clinical trials. This consistent yet straightforward method has the potential to systemize CAC scoring in both gated and non-gated scans.

Subclinical coronary artery disease in Swiss HIV-positive and HIV-negative persons

Aims

HIV-positive persons have increased cardiovascular event rates but data on the prevalence of subclinical atherosclerosis compared with HIV-negative persons are not uniform. We assessed subclinical atherosclerosis utilizing coronary artery calcium (CAC) scoring and coronary computed tomography angiography (CCTA) in 428 HIV-positive participants of the Swiss HIV Cohort Study and 276 HIV-negative controls concurrently referred for clinically indicated CCTA.

Methods and results

We assessed the association of HIV infection, cardiovascular risk profile, and HIV-related factors with subclinical atherosclerosis in univariable and multivariable analyses. HIV-positive participants (median duration of HIV infection, 15 years) were younger than HIV-negative participants (median age 52 vs. 56 years; P < 0.01) but had similar median 10-year Framingham risk scores (9.0% vs. 9.7%; P = 0.40). The prevalence of CAC score >0 (53% vs. 56.2%; P = 0.42) and median CAC scores (47 vs. 47; P = 0.80) were similar, as was the prevalence of any, non-calcified/mixed, and high-risk plaque. In multivariable adjusted analysis, HIV-positive participants had a lower prevalence of calcified plaque than HIV-negative participants [36.9% vs. 48.6%, P < 0.01; adjusted odds ratio (aOR) 0.57; 95% confidence interval (CI) 0.40-0.82; P < 0.01], lower coronary segment severity score (aOR 0.72; 95% CI 0.53-0.99; P = 0.04), and lower segment involvement score (aOR 0.71, 95% CI 0.52-0.97; P = 0.03). Advanced immunosuppression was associated with non-calcified/mixed plaque (aOR 1.97; 95% CI 1.09-3.56; P = 0.02).

Conclusion

HIV-positive persons in Switzerland had a similar degree of non-calcified/mixed plaque and high-risk plaque, and may have less calcified coronary plaque, and lower coronary atherosclerosis involvement and severity scores than HIV-negative persons with similar Framingham risk scores.

Two-dimensional echocardiographic measurements of the right coronary artery in healthy horses - a pilot study

Background

Precise understanding of the dimensions of the vascular lumina is essential for accurate interpretation of cardiac vessels imaging. To the authors’ best knowledge, this is the first study focusing on the ultrasound measurement of the right coronary artery (RCA) in the horse. The aim of this study was to determine both the ultrasonographic range of the normal diameter and lumen area of the RCA in horses and the influence of gender, age and level of training on the RCA dimensions. An additional aim of the study was to assess intra- and inter-observer repeatability of the collected measurements.

Methods

Thirty-six privately owned, healthy horses were included in the study. The internal lumen diameter and the area of the RCA were measured in the right parasternal long axis view in the 3rd intercostal space during systole and diastole. The results were compared between groups using the analysis of variance (ANOVA) and Student’s t-test. The correlation between the physiological parameters and the RCA was assessed using Pearson correlation coefficient. Student’s t-test was used to compare the results obtained by two researchers and from two scanners.

Results

The mean diameter of the RCA was 13.1 ± 1.5 mm in systole and 11.5 ± 1.3 mm in diastole, and the mean area was 1.3 ± 0.2 cm² and 1.1 ± 0.2 cm², respectively. There were no statistically significant measurement differences between geldings and mares. A positive correlation between body weight and RCA dimensions as well as height and RCA dimensions were seen. There was a negative correlation between the age and the RCA area. A statistically significant difference in the RCA area was seen between race and retired horses. Intra- and inter-observer agreement was strong with a few statistically significant differences.

Conclusions

The age, size, and level of training may affect the ultrasound measurement of the RCA in horses. Non-invasive transthoracic echocardiography may be used to assess the size of the right coronary vessel in various types of horses.

Intracranial Carotid Calcification on Cranial Computed Tomography: Visual Scoring Methods, Semiautomated Scores, and Volume Measurements in Patients With Stroke

Supplemental Digital Content is available in the text.

Intracranial internal carotid artery calcification is associated with cerebrovascular risk factors and stroke, but few quantification methods are available. We tested the reliability of visual scoring, semiautomated Agatston score, and calcium volume measurement in patients with recent stroke.

Noncalcified coronary plaque volumes in healthy people with a family history of early onset coronary artery disease

BACKGROUND

Although age and sex distributions of calcified coronary plaque have been well described in the general population, noncalcified plaque (NCP) distributions remain unknown. This is important because NCP is a putative precursor for clinical coronary artery disease and could serve as a sentinel for aggressive primary prevention, especially in high-risk populations. We examined the distributions of NCP and calcified coronary plaque in healthy 30- to 74-year-old individuals from families with early onset coronary artery disease.

METHODS AND RESULTS

Participants in the GeneSTAR family study (N=805), mean age 51.1±10.8 years, 56% women, were screened for coronary artery disease risk factors and coronary plaque using dual-source computed tomographic angiography. Plaque volumes (mm(3)) were quantified using a validated automated method. The prevalence of coronary plaque was 57.8% in men and 35.8% in women (P<0.0001). NCP volume increased with age (P<0.001) and was higher in men than women (P<0.001). Although NCP, as a percentage of total plaque, was inversely related to age (P<0.01), NCP accounted for most of the total plaque volume at all ages, especially in men and women <55 years (>70% and >80%, respectively). Higher Framingham risk was associated with the number of affected vessels (P<0.01), but 44% of men and 20.8% of women considered intermediate risk had left main and 3-vessel disease involvement.

CONCLUSIONS

The majority of coronary plaque was noncalcified, particularly in younger individuals. These findings support the importance of assessing family history and suggest that early primary prevention interventions may be warranted at younger ages in families with early onset coronary artery disease.

Utility of coronary artery calcium scoring in the evaluation of patients with chest pain

Although coronary artery calcium (CAC) scoring has an established role in risk-stratifying asymptomatic patients at intermediate risk of coronary heart disease (CHD), its utility in the evaluation of patients with chest pain is uncertain. We conducted a literature review of articles investigating the utility of: (1) CAC scoring in elective patients with indeterminate chest pain symptoms, (2) CAC as a "gatekeeper" in the triage of patients presenting to the emergency department (ED) with chest pain, and (3) the cost-effectiveness of the use of CAC scoring in the ED. We also evaluated the predictive accuracy of the absence of CAC in a pooled analysis of applicable studies. Only studies evaluating patients classified as low or intermediate risk were included. Low to intermediate risk was established by Framingham risk scores, Thrombolysis in Myocardial Infarction scores, Diamond-Forrester classification, or by the absence of typical angina symptoms, ischemic electrocardiogram, positive cardiac biomarkers, or a prior history of CHD. In our pooled analysis, the presence of any CAC resulted in a high sensitivity (range 70%-100%) for predicting the presence of obstructive coronary disease among symptomatic patients subsequently referred for coronary angiography. More importantly, a CAC score of 0 in low- and intermediate-risk ED populations with chest pain had a high negative predictive value (99.4%) for CHD events over an average follow-up of 21 months. CAC scoring also seems cost-effective in this population. Although further research is needed, carefully selected ED patients with a normal electrocardiogram, normal cardiac biomarkers, and CAC = 0 may be considered for early discharge without further testing.

Severity of inducible myocardial ischemia predicts incident acute coronary syndromes in asymptomatic individuals with a family history of premature coronary artery disease

BACKGROUND

Although the severity of inducible ischemia provides incremental prognostic information in persons with known or suspected coronary artery disease (CAD), its significance for predicting long-term CAD outcomes in apparently healthy populations is unknown. This study was designed to evaluate the presence and degree of myocardial ischemia in asymptomatic siblings of persons with premature CAD <60 years of age and to determine its significance for predicting incident acute coronary syndromes (ACS) during follow-up of 5 to 25 years.

METHODS

Siblings (n = 1,287, age 30-59 years, 55% female) were screened for traditional risk factors, underwent exercise treadmill testing with nuclear perfusion imaging, and were followed for the development of ACS (mean follow-up 11.6 ± 5.1 years). The severity of ischemia was assessed by semiquantitative methods using the standard 17-segment model and then categorized by the percent maximal summed stress score as none (0%), minimal (1% to <5%), mild (5% to 10%), moderate (10% to 15%), or severe (≥15%).

RESULTS

ACS occurred in 132 subjects (10.3%) and included sudden cardiac death (n = 13), acute MI (n = 62), and unstable angina with revascularization (n = 57). The presence of no (88%), minimal (6%), mild (5%), and moderate/severe (1%) ischemia was associated with an ACS incidence of 8.3%, 19.7%, 25.0%, and 38.9%, respectively (P < .0001 for trend). Kaplan-Meier event-free survival analyses by myocardial ischemia severity categories showed that even minimal and mild myocardial ischemia were associated with greater ACS incidence detectable as early as 2 years after baseline. A Cox proportional hazard model, adjusted for risk factors and follow-up time, showed that each 5% increment in the severity of ischemia resulted in a 77% increase in the hazard of incident ACS (P < .001).

CONCLUSION

Inducible myocardial ischemia is prevalent in asymptomatic siblings of persons with early onset CAD. Most ischemia is minimal or mild in severity, and although the severity of ischemia is associated with the risk of ACS in a graded fashion, the presence of even minimal and mild perfusion defects predicts worse CAD outcomes in this population.

Diagnostic and prognostic value of absence of coronary artery calcification

OBJECTIVES

In this study, we systematically assessed the diagnostic and prognostic value of absence of coronary artery calcification (CAC) in asymptomatic and symptomatic individuals.

BACKGROUND

Presence of CAC is a well-established marker of coronary plaque burden and is associated with a higher risk of adverse cardiovascular outcomes. Absence of CAC has been suggested to be associated with a very low risk of significant coronary artery disease, as well as minimal risk of future events.

METHODS

We searched online databases (e.g., PubMed and MEDLINE) for original research articles published in English between January 1990 and March 2008 examining the diagnostic and prognostic utility of CAC.

RESULTS

A systematic review of published articles revealed 49 studies that fulfilled our criteria for inclusion. These included 13 studies assessing the relationship of CAC with adverse cardiovascular outcomes in 64,873 asymptomatic patients. In this cohort, 146 of 25,903 patients without CAC (0.56%) had a cardiovascular event during a mean follow-up period of 51 months. In the 7 studies assessing the prognostic value of CAC in a symptomatic population, 1.80% of patients without CAC had a cardiovascular event. Overall, 18 studies demonstrated that the presence of any CAC had a pooled sensitivity and negative predictive value of 98% and 93%, respectively, for detection of significant coronary artery disease on invasive coronary angiography. In 4,870 individuals undergoing myocardial perfusion and CAC testing, in the absence of CAC, only 6% demonstrated any sign of ischemia. Finally, 3 studies demonstrated that absence of CAC had a negative predictive value of 99% for ruling out acute coronary syndrome.

CONCLUSIONS

On the basis of our review of more than 85,000 patients, we conclude that the absence of CAC is associated with a very low risk of future cardiovascular events, with modest incremental value of other diagnostic tests in this very low-risk group.

Influence of symptomatic status on the prevalence of obstructive coronary artery disease in patients with zero calcium score

BACKGROUND

CAC has been used to predict obstructive CAD on invasive coronary angiography. However, it is unknown how the prevalence of obstructive CAD in patients with zero CAC is influenced by the presence or absence of chest pain.

METHODS

210 consecutive patients referred for CAC and CorCTA were included in this analysis. Chest pain was defined based on the Diamond-Forrester classification.

RESULTS

134 patients (64%) were symptomatic and 76 (36%) were asymptomatic. Seventy patients had negative (33%); 140 had positive CAC (67%). In the symptomatic group with zero CAC, 8.2% (4/49) had an obstructive, non-calcified plaque; of these, 3 were <45 years. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CAC in the symptomatic population for detection of obstructive CAD were 0.86 (0.66-0.95), 0.42 (0.33-0.52), 0.28 (0.19-0.39) and 0.92 (0.8-0.97), respectively (p=0.007). No asymptomatic subject with zero CAC had obstructive CAD. Sensitivity, specificity, PPV and NPV of CAC in the asymptomatic population for detection of obstructive CAD were 1.00 (0.66-1.00), 0.32 (0.21-0.45), 0.18 (0.10-0.31) and 1.00 (0.80-1.00), respectively (p=0.05). Optimal cut-points to predict obstructive CAD and AUC were significantly different in symptomatic versus asymptomatic subjects (91 and 0.78 vs. 296 and 0.89, respectively) (p=0.005). CAC performed much better in symptomatic patients >45 years compared to younger patients to exclude obstructive CAD (AUC: 0.83 vs. 0.5, p<0.001; NPV=0.98).

CONCLUSIONS

CAC is better in asymptomatic compared to symptomatic subjects, especially in patients <age 45, to exclude obstructive CAD. Symptoms and age should be considered when interpreting CAC.

Antioxidant Vitamin Intake and Subclinical Coronary Atherosclerosis

Numerous studies have evaluated the association between antioxidants and coronary atherosclerosis but have been limited by its study among individuals with advanced atherosclerosis. The authors studied 865 consecutive patients, 39-45 years of age, without known coronary artery disease and presenting for a periodic physical examination. Antioxidant intake was assessed with the Block Dietary Questionnaire, and coronary atherosclerosis was identified by measuring coronary artery calcification using electron beam computed tomography. The mean age was 42 (+/-2), 83% were male, and the prevalence of coronary artery calcification was 20%. Vitamin supplements were used by 56% of the participants, and the mean (+/-SD) daily intake (dietary plus supplemental) of vitamins A, C, and E were 1683 mg (+/-1245), 371 mg (+/-375), and 97 mg (+/-165), respectively. There was no significant correlation between coronary artery calcification score and individual vitamin or total antioxidant vitamin intake, even after adjusting for traditional cardiac risk factors. The highest quartile of vitamin E was positively associated with calcification (odds ratio=1.77; 95% confidence interval, 1.02-3.06). Antioxidant vitamin intake is not significantly related to coronary artery calcification, implying that there is no effect on the development of early coronary atherosclerosis. High doses of vitamin E may confer an increased risk of calcified atherosclerosis.

Evaluation of arteriosclerotic changes in the intracranial carotid artery using the calcium score obtained on plain cranial computed tomography scan: Correlation with angiographic changes and clinical outcome

PURPOSE

This study evaluated the correlation between quantified calcification of the carotid siphon and arteriosclerotic changes on angiography as well as clinical outcome. We used the calcium score obtained from intracranial carotid arteries viewed on plain CT.

METHOD/MATERIALS

We examined carotid siphons of 72 consecutive patients who had undergone both plain CT and angiography of the brain. We calculated calcium scores of the carotid siphon. Arteriosclerotic changes on angiography were categorized as "smooth," "irregular," or "stenosis." We assessed the correlation between the scores and arteriosclerotic changes both in the carotid siphon and the bifurcation. We reviewed clinical records approximately 2 years after examination and evaluated the scores of patients who did and did not experience cerebral strokes.

RESULTS

In the evaluation between angiographic findings of siphon and calcium score of the siphon, there were statistically significant differences between the "smooth" and "irregular", "irregular" and "stenosis" and the "smooth" and "stenosis". In the evaluation between angiographic findings of bifurcation and the score of the siphon, a statistically significant difference was only seen between "smooth" and "stenosis". No significant differences in calcium scores were observed between patients groups who did or did not experience a cerebral stroke.

CONCLUSIONS

There were a positive correlation between calcium scores on CT and angiographic changes of arteriosclerosis in the siphon as well as bifurcation, indicating angiographic changes can be predicted using calcium scores. However, the degree of calcification in the siphon cannot be used to predict the possibility of a future cerebral stroke.

Coronary artery calcium score, risk factors, and incident coronary heart disease events

BACKGROUND

Whether the absence of coronary artery calcium, or conversely the presence of high volumes of coronary artery calcium, may alter assessment of coronary heart disease risk based on traditional risk factors is uncertain. We sought to identify a potential threshold of coronary artery calcium for clinical use and examine the predictive power of coronary artery calcium in individuals categorized using conventional coronary heart disease risk assessment.

METHODS

The study included 10,746 men and women (36.3%) with a mean age of 53.8+/-9.9 years who were either physician- or self-referred for electron beam tomography scanning to a preventive medical clinic. Coronary heart disease risk factors were elicited by use of a questionnaire.

RESULTS

During a mean follow-up of 3.5 years, 81 primary events (coronary heart disease death or nonfatal myocardial infarction) occurred. Among individuals with a coronary artery calcium score of zero, the primary event rate was very low (0.4 events per 1000 person-years of observation). When participants were stratified by self-reported coronary heart disease risk factors (0-2, or 3-4), a coronary artery calcium score >or=100 was associated with substantially increased risk of coronary heart disease events within each level of stratification. In a subgroup of participants with available clinical data, similar results were found when participants were categorized by Framingham risk scores.

CONCLUSIONS

Coronary artery calcium score can identify individuals at increased risk for coronary heart disease events who otherwise would be considered low-risk based on clinical assessment. A coronary artery calcium score of zero is associated with very low risk for coronary heart disease in the short to intermediate term ( approximately 3.5 years) regardless of the number of risk factors present.

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.

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.

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.

Coronary artery calcium score and coronary heart disease events in a large cohort of asymptomatic men and women

Coronary artery calcium (CAC), a measure of subclinical coronary heart disease (CHD), may be useful in identifying asymptomatic persons at risk of CHD events. The current study included 10,746 adults who were 22-96 years of age, were free of known CHD, and had their CAC quantified by electron-beam tomography at baseline as part of a preventive medical examination at the Cooper Clinic (Dallas, Texas) during 1995-2000. During a mean follow-up of 3.5 years, 81 hard events (CHD death, nonfatal myocardial infarction) and 287 total events (hard events plus coronary revascularization) occurred. Age-adjusted rates (per 1,000 person-years) of hard events were computed according to four CAC categories: no detectable CAC and incremental sex-specific thirds of detectable CAC; these rates were, respectively, 0.4, 1.5, 4.8, and 8.7 (trend p<0.0001) for men and 0.7, 2.3, 3.1, and 6.3 (trend p=0.02) for women. CAC levels also were positively associated with rates of total CHD events for women and men (trend p<0.0001 each). The association between CAC and CHD events remained significant after adjustment for CHD risk factors. CAC was associated with CHD events in persons with no baseline CHD risk factors and in younger (aged <40 years) and older (aged >65 years) study participants. These findings show that CAC is associated with an increased risk of CHD events in asymptomatic women and men.

Alcohol intake is not associated with subclinical coronary atherosclerosis

BACKGROUND

The inverse relation between alcohol intake and clinical coronary artery disease (CAD) is well established, although the mechanisms remain speculative. We studied the relation between alcohol intake and subclinical CAD to assess the possible role of alcohol in atherogenesis.

METHODS

We conducted a prospective study of 731 consecutive, consenting, active-duty US Army personnel (39 to 45 years of age) without known CAD who were undergoing a routine physical examination. Each participant was surveyed with the validated Block dietary questionnaire, which included detailed information on alcohol intake as wine, beer, or liquor. Subclinical CAD was determined by means of electron beam computed tomography to quantify coronary artery calcification (CAC).

RESULTS

The mean age was 42 (+/-2); 83% were male, 71% were white, and 82% were college graduates. The prevalence of CAC was 18.6% (mean CAC score = 12 +/- 69). Twenty-two percent drank alcohol daily, with an average of 2.4 drinks per day. Systolic blood pressure was correlated with number of drinks per day (r = 0.10, P = .025). Among drinkers, HDL was weakly correlated with daily alcohol consumption (r = 0.10, P = .025). There was no relation between the CAC score and the alcohol intake as measured by drinks per day (OR, 1.02; 95% CI, 0.64 to 1.63; 1.13, 0.59 to 2.15; 1.26, 0.69 to 2.59, for less than 1, 1 to 2, and more than 2 drinks per day, respectively). Stratified analyses based on type of alcohol and multivariate analyses indicated no independent relation between any type or quantity of alcohol intake and the presence or extent of coronary calcification.

CONCLUSIONS

Alcohol intake does not appear to be inversely related to subclinical CAC, implying that previous observations of a protective effect of alcohol on clinical CAD may involve factors related to plaque stability rather than atherogenesis.

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.

Valvular and thoracic aortic calcium as a marker of the extent and severity of angiographic coronary artery disease

BACKGROUND

The presence of calcified extracoronary structures as a useful indicator of underlying coronary artery disease (CAD) has not yet been established. The purpose of this study was to evaluate whether valvular and thoracic aortic calcification is associated with obstructive CAD.

METHODS

We evaluated 99 patients who underwent both coronary angiography and electron beam tomography (EBT) coronary scanning. We identified the presence, absence, and amount of calcification in the aortic valve (AVC), mitral annulus (MAC), descending aorta (DAC), and ascending aorta (AAC). The extent of CAD was graded according to the number of vessels diseased (VD).

RESULTS

Patients with multivessel disease (MVD) had a higher proportion of DAC. The presence of DAC significantly increased the specificity of EBT to detect CAD (58% with a calcium score >0 to 88% for calcium score>0 and DAC >0, P <.001). Both AAC and DAC were associated with a significantly higher rate of MVD in women (DAC, 63% in MVD vs 19% without, P <.01.; AAC, 65% vs 22%, P <.05). MAC had no relationship to either stenosis severity or the presence of obstructive CAD. AVC was the strongest predictor of the severity of CAD and predicted the presence of 3-vessel disease.

CONCLUSION

AVC and thoracic aortic calcification as detected with EBT are associated with the angiographic extent and severity of CAD and add incremental diagnostic value to the coronary artery calcium score. MAC does not add incremental value.

Coronary artery disease in HIV infected patients

OBJECTIVE

To assess the incidence, clinical features, treatment, and follow-up of coronary events in HIV-infected patients over a period of 5 years.

PATIENTS AND PARTICIPANTS

A cohort of 840 patients.

MEASUREMENTS AND RESULTS

A coronary event occurred in 17 patients (5.9/1000 persons-years). Sixteen of them were exposed to highly active antiretroviral therapy (HAART). Patients with coronary events differed in age (48.3 vs. 43 years), CD4 T-cell count (284 vs. 486/mm(3)), total cholesterol (6.2 vs. 5.3 mmol/l), HDL cholesterol (0.72 vs. 1.16 mmol/l), and LDL cholesterol (4.95 vs. 3.391.61 mmol/l). No difference was observed regarding duration of HAART, weight, glucose level, or smoking status between the two groups. Acute coronary syndrome was the first manifestation in 14 patients. Coronary angiography showed 2.56 stenosis per patient, with a single vessel involvement in one-half. Percutaneous angioplasty was performed in all cases, with stenting in 11. After a mean follow-up of 36 months, 14 patients remain alive. Restenosis ( n=4) occurred in 3 patients (PTCA 3; stenting 4). All 14 patients are free of heart failure symptoms. Their mean left ventricular ejection fraction is 61%.

CONCLUSIONS

A higher coronary-event rate is observed among HIV-infected patients, associated with drug-induced metabolic disturbances and a high prevalence of tobacco smoking. However, treatment and prognosis of acute myocardial infarction has no specificity.

Noninvasive assessment of coronary artery disease by multislice spiral computed tomography using a new retrospectively ECG-gated image reconstruction technique

The present study was designed to investigate the accuracy of multislice spiral computed tomography (MSCT) in detecting coronary artery disease, compared with coronary angiography (CAG), using a new retrospectively ECG-gated reconstruction method that reduced cardiac motion artifact. The study group comprised 54 consecutive patients undergoing MSCT and CAG. MSCT was performed using a SOMATOM Volume Zoom (4-detector-row, Siemens, Germany) with slice thickness 1.0 mm, pitch 1.5 (table feed: 1.5 mm per rotation) and gantry rotation time 500 ms. Metoprolol (20-60 mg) was administered orally prior to MSCT imaging. ECG-gated image reconstruction was performed with the reconstruction window (250 ms) positioned immediately before atrial contraction in order to reduce the cardiac motion artifact caused by the abrupt diastolic ventricular movement occurring during the rapid filling and atrial contraction periods. Following inspection of the volume rendering images, multiplanar reconstruction images and axial images of the left main coronary artery (LMCA), left anterior descending artery (LAD), left circumflex artery (LCx) and right coronary artery (RCA) were obtained and evaluated for luminal narrowing. The results were compared with those obtained by CAG. Of 216 coronary arteries, 206 (95.4%) were assessable; 10 arteries were excluded from the analysis because of severe calcification (n=4), stents (n=3) or insufficient contrast enhancement (n=3). The sensitivity to detect coronary stenoses >or=50% was 93.5% and the specificity to define luminal narrowing <50% was 97.2%. The positive predictive value and the negative predictive value were 93.5% and 97.2%, respectively. The sensitivity was still satisfactory (80.6%) even when non-assessable arteries were included in the analysis. The new retrospectively ECG-gated reconstruction method for MSCT has excellent diagnostic accuracy in detecting significant coronary artery stenoses.

Coronary heart disease in HIV-infected patients in the highly active antiretroviral treatment era

OBJECTIVES

To assess the incidence and the clinical features of coronary heart disease in HIV-infected patients. To assess atherosclerosis risk factors in this population.

METHODS

A review of our experience consisting of 16 patients with acute myocardial infarction (AMI) was the basis of our retrospective analysis of two cohorts in France. Incidence was compared with the national database on the incidence of AMI in the general population.

RESULTS

Incidence appears to be between 5 and 5.5 per 1000 person-years among HIV-infected patients. This accounts for at least a threefold increase in incidence (1.52 per 1000 person-years reported in the Monica database registry in France). Age of onset of AMI in HIV-infected patients (younger than 50 years in most cases) is a point of major concern and is an indirect way to confirm the increased incidence. AMI was typically of sudden onset without prior history of angina pectoris. Treatment and prognosis of AMI in this population has no specificity. Patients with coronary heart disease present several risk factors such as tobacco smoking, hypertension, diabetes mellitus and low high-density lipoprotein level. The links between AMI and protease inhibitor exposure is still a matter of debate, and longer duration of follow-up is needed in order to reach any conclusion.

CONCLUSIONS

Coronary heart disease is of a higher than expected incidence in HIV-infected patients. The limitation of risk factors (mainly tobacco smoking) is a new challenge. An adaptation of the Framingham score is necessary to state the individual risk. Prospective, controlled studies are necessary to assess new strategies such as the role of statins and switching therapeutic regimens.

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.

Noninvasive coronary artery imaging by multislice spiral computed tomography

Although the excellent spatial resolution of multislice spiral computed tomography (MSCT) enables the coronary arteries to be visualized, its limited temporal resolution results in poor image reproducibility because of cardiac motion artifact (CMA) and hence limits its widespread clinical use. A novel retrospectively ECG-gated reconstruction method has been developed to minimize CMA. In 88 consecutive patients, the scan data were reconstructed using 2 retrospectively ECG-gated reconstruction methods. Method 1: the end of the reconstruction window (250 ms) was positioned at the peak of the P wave on ECG, which corresponded to the end of the slow filling phase during diastole immediately before atrial contraction. Method 2 (conventional method): relative retrospective gating with 50% referred to the R-R interval was performed so that the beginning of the reconstruction window (250 ms) was positioned at the halfway point between the R-R intervals of the heart cycle. The quality of the coronary artery images was evaluated according to the presence or absence of CMA. The assessment was applied to the left main coronary artery (LMCA), the left anterior descending artery (LAD, segments #6, #7 and #8), the left circumflex artery (LCx, segments #11 and #13) and the right coronary artery (RCA, segments #1, #2 and #3). The first diagonal artery (#9-1), the obtuse marginal artery (#12-1), the posterior descending artery (#4-PD), the atrioventricular node branch (#4-AV) and the first right ventricular branch (RV) were also evaluated. Of the 88 patients, 85 were eligible for image evaluation. Method 1 allowed visualization of the major coronary arteries without CMA in the majority of patients. The LCA system (segments #5-7, #11 and #13) and the proximal portion of the RCA were visualized in more than 94% of patients. Artifact-free visualization of the distal portion of the LAD (segment #8) and RCA (#4PD and #4AV), and side branches (#9-1, #12-1 and RV) was also achieved in more than 80% of patients. On the other hand, CMA occurred frequently on images obtained by Method 2. The LCx and RCA systems were the most affected by CMA, revealing only 41% artifact-free visualization of the segment #13, 39% of #1, 15% of #2 and 32% of #3. Thus, Method 1, which avoids the ventricular motion occurring during the rapid filling and atrial contraction phases, gives superior image quality over the conventional ECG-gated reconstruction method.

Aortic valve calcium on spiral computed tomography (dual slice mode) is associated with advanced coronary calcium in hypertensive patients

BACKGROUND

Aortic valve calcium (AVC) is common in the elderly and is associated with an increase risk of death from cardiovascular causes and of myocardial infarction. The goal of the present study was to determine whether an association exists between the presence of AVC and coronary calcium (CC) in high-risk hypertensive patients as detected by spiral computed tomography (dual slice mode) (DHCT).

DESIGN AND METHODS

Three hundred and seventy-six hypertensive patients participating in the International Nifedipine Gastrointestinal Therapeutic System (GITS) Study of Intervention as a Goal in Hypertension Treatment (INSIGHT) in our region were included (197 men and 179 women, age range 55-79 years). All underwent DHCT of the heart for CC scoring using previously published methods. A positive test for the presence of CC was defined as the presence of at least one lesion with an area of 0.5 mm and DHCT density above 90 Hounsfield units (total CC score >0). CC was considered advanced when total calcium score was >300. AVC was defined by DHCT as any detected calcified deposit in the region of the aortic valve. Patients without AVC served as the control group.

RESULTS

AVC was documented in 70 patients (36 men, 34 women; mean age 66 +/- 5 years, range 57-79 years). The age- and sex-matched non-AVC group (control group) included 306 patients (161 men, 145 women; mean age 67 +/- 5 years, range 55-75 years). There were no intergroup differences in risk factors for atherosclerosis. Significant differences were found between AVC and the control groups for mean CC score (388 +/- 754 compared with 147 +/- 307, P< 0.001) and between the presence of advanced CC and the control group (27 compared with 15%, P= 0.02). Significant differences were also found for the presence of three-vessel calcification (36 compared with 21%, P= 0.01) and the number of vessels involved (1.8 +/- 1.1 compared with 1.4 +/- 1.1, P= 0.01). Stepwise logistic regression found age [odds ratio (OR) 1.08, 95% confidence intervals (CI) 1.03-1.15), gender (OR 0.45, 95% CI 0.25-0.82) and AVC (OR 2.07, 95% CI 1.06-4.02)] to be the only variables that predict advanced CC.

CONCLUSIONS

Our study demonstrated a significant association between the presence of AVC and advanced CC on spiral computed tomography. These results strengthen earlier findings of a high association between AVC and increased risk of death from cardiovascular causes.

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.

Combined coronary and mitral annulus calcium detection in the non-invasive diagnosis of coronary artery disease in patients with systemic hypertension

BACKGROUND

Although the presence of coronary calcium (CC) on fast spiral computed tomography (FSCT) is a powerful predictor of coronary artery disease (CAD), both the specificity and positive predictive value (PPV) of CC in CAD diagnosis are modest. Since previous studies have shown an association between mitral annular calcification (MAC) and coronary atherosclerosis, we aimed to investigate whether combined coronary and MAC detection could improve the non-invasive diagnosis of CAD.

DESIGN AND METHODS

Our study comprised 522 patients (284 men and 238 women, age ranged from 52-80 years, mean 65 +/- 6 years) who underwent FSCT of the coronaries as well as echo-Doppler examination. Among them, 97 patients had prior diagnosis of prevalent proven CAD (CAD group) while 425 patients were without clinically manifested CAD (the No CAD group).

RESULTS

The prevalence of CC in the CAD group was 95 versus 68% in the No CAD group (P = 0.001). The prevalence of MAC in CAD group was 63 versus 51% in No CAD group (P = 0.03). Sensitivity and negative predictive value (NPV) of CC as a predictor of CAD were 95 and 96% respectively, but specificity and PPV were low: 32 and 24% respectively. Sensitivity and NPV of MAC as predictors of CAD were 63 and 85% respectively; specificity and PPV, 49 and 22% respectively. Using of combined CC and MAC evaluation in the prediction led to some specificity improvement at the expense of a similar sensitivity reduction, without a considerable gain in the total accuracy of the method.

CONCLUSIONS

Coronary calcium detection on FSCT in hypertensive patients yields excellent sensitivity and NPV but relatively low specificity and PPV for clinically manifested CAD. Mitral annular calcification assessment yields a low sensitivity and specificity and its addition to CC evaluation does not improve non-invasive diagnosis of CAD.

Calcium scoring of the coronary artery by electron beam CT: how to apply an individual attenuation threshold

OBJECTIVE

Our aim was to assess the inter- and intraindividual variability of the attenuation threshold used to identify coronary artery calcification on electron beam CT and to illustrate a new threshold method.

MATERIALS AND METHODS

We measured the soft-tissue attenuation of regions surrounding the coronary arteries at the level of the left main coronary artery ostium (high level) and at the bottom of the heart (low level) in 48 consecutive patients (22 men, 26 women). Mean +/- 2 standard deviations (SD) of soft-tissue attenuation and variance of soft-tissue density and SDs were calculated at each level for every patient. It was assumed that setting an attenuation threshold greater than or equal to 3 SDs above that of soft tissue at each myocardial level would eliminate 99.5% of all scatter artifacts, allowing precise identification of calcific deposits.

RESULTS

For the entire patient cohort, the average soft-tissue attenuation was 41 H and 35 H at the high and low levels, respectively (p < 0.01), indicating a large intraindividual variability. The SDs of soft-tissue attenuation measured by the computer software at the high and low levels were not different (26 H at the high level and 28 H at the low level; p = not significant). However, the calculated SD of the individual mean soft-tissue attenuation was 5 H at the high level and 8 H at the low level, again indicating a large intraindividual variability (p < 0.01). The addition of 3 measured SDs above the mean individual soft-tissue attenuation predicted a mean threshold of 120 and 121 H at the high and low levels, respectively, but with a wide interindividual variability (83-193 H at the high level and 79-242 H at the low level). There was a strong correlation between body weight and SD of soft-tissue attenuation at the low level (r = 0.75, p < 0.001) and a weaker but statistically significant correlation between weight and SD of soft-tissue attenuation at the high level (r = 0.51, p < 0.001).

CONCLUSION

For the patients in this study, a threshold of 120 H for the detection of coronary calcification by electron beam CT seemed more appropriate than a threshold of 130 H, which is currently in use. However, given the great inter- and intraindividual variability, a biologic threshold tailored to the individual patient and to each individual imaging level should be used instead of a fixed threshold.

Detection of subclinical cardiovascular disease: the emerging role of electron beam computed tomography

BACKGROUND

Although extraordinary advances have been made in the management of advanced coronary artery disease, little progress has been made in its prevention. Traditional screening methods utilizing risk factor profiles and exercise treadmill tests have failed to identify populations who will subsequently have coronary events with a high degree of predictive accuracy.

METHODS

We review the pathobiologic basis and clinical utility of electron beam computed tomography (EBCT) to detect coronary artery calcium as a screening tool for subclinical coronary artery disease. Because EBCT is able to perform subsecond imaging of the heart, it can detect and quantitate coronary artery calcium with a high degree of precision. Coronary artery calcium is a marker of complex atherosclerosis.

RESULTS

Over 4,000 asymptomatic patients in several series have been studied with EBCT and followed prospectively for an average of 42 months (range 37-72 months). A positive scan is associated with a risk ratio for future coronary events of 8.7 (95% confidence interval 2.67 to 28.13). These data indicate that EBCT has the ability to detect subclinical coronary artery disease and predict future coronary events better than any previous existing method or technology.

CONCLUSION

EBCT coronary artery screening may prove to be a valuable adjunct to the traditional methods for the detection of subclinical coronary artery disease and to identify those who would benefit from focused preventive therapies.

Association of mitral annulus calcification, aortic valve sclerosis and aortic root calcification with abnormal myocardial perfusion single photon emission tomography in subjects age < or =65 years old

OBJECTIVES

We examined the hypothesis that mitral annulus calcification (MAC), aortic valve sclerosis (AVS) and aortic root calcification (ARC) are associated with coronary artery disease (CAD) in subjects age < or =65 years.

BACKGROUND

Mitral annulus calcification, AVS and ARC frequently coexist and are associated with coronary risk factors and CAD in the elderly.

METHODS

We studied 338 subjects age < or =65 years who underwent evaluation of chest pain with myocardial perfusion single photon emission computed tomography (SPECT) and a two-dimensional transthoracic echocardiogram for other indications. The association of MAC, AVS and ARC with abnormal SPECT was evaluated by using chi-square analyses and logistic regression analyses.

RESULTS

Compared with no or one calcium deposit and no or one coronary risk factor other than diabetes, multiple (> or =2) calcium (or sclerosis) deposits with diabetes or multiple (> or =2) coronary risk factors were significantly associated with abnormal SPECT in women age < or =55 years old (odds ratio [OR], 20.00), in women age >55 years old (OR, 10.00) and in men age < or =55 years old (OR, 5.55). Multivariate analyses identified multiple calcium deposits as a significant predictor for an abnormal SPECT in women (p < 0.001), younger subjects age < or =55 years (p < 0.05) and the total group of subjects (p < 0.01).

CONCLUSIONS

When coronary risk factors are also taken into consideration, the presence of multiple calcium deposits in the mitral annulus, aortic valve or aortic root appears to be a marker of CAD in men < or =55 years old and women.

Age and gender distributions of coronary artery calcium detected by electron beam tomography in 35,246 adults

Electron beam tomography (EBT) is a noninvasive method used to detect coronary artery calcium (CAC). Due to the age-associated increase in incidence and magnitude of CAC, interpretation of results can be difficult. The purpose of this study was to develop a set of age- and gender-stratified CAC distributions to serve as standards for the clinical interpretation of EBT scans. Between 1993 and 1999, 35,246 asymptomatic subjects, 30 to 90 years of age, were self-referred for CAC screening using an Imatron EBT scanner. CAC score was calculated based on the number, areas, and peak computed tomographic density for each detected calcific lesion. CAC score in each coronary artery was equal to the sum of all lesions for that artery and the total CAC score was equal to the sum of the score of each artery. Total CAC scores were assigned to a percentile according to age and gender. CAC scores were reported at the 10th, 25th, 50th, 75th, and 90th percentiles for 16 age and/or gender groups. The prevalence of CAC increased with age for men and women. The extent of CAC differed significantly between men and women in the same age group. In summary, this study reports the distribution of CAC score by age and gender. Knowledge of the distribution of CAC, the effect of age on the total CAC score as well as the differences in total CAC scores that exist between men and women of similar age will assist the clinician in interpreting EBT CAC results.

C-reactive protein is not associated with the presence or extent of calcified subclinical atherosclerosis

BACKGROUND

Both high-sensitivity C-reactive protein (hsCRP) and electron beam computed tomography (EBCT) coronary artery calcification (CAC) are valid markers of cardiovascular risk. It is unknown whether hsCRP is a marker of atherosclerotic burden or whether it reflects a process (eg, inflammatory fibrous cap degradation) leading to acute coronary events.

METHODS

A nested case-control study was performed of 188 men enrolled in the Prospective Army Coronary Calcium study. The serum hsCRP levels (latex agglutination assay) were evaluated in subjects with CAC (CAC score >0, n = 94) and compared with age- and smoking status-matched control subjects (CAC score 0, n = 94).

RESULTS

Levels of hsCRP in the highest quartile were related to the following coronary risk factors: smoking status, low-density lipoprotein cholesterol, body mass index, glycosylated hemoglobin, fibrinogen, and homocysteine. The mean hsCRP level was similar in cases (+CAC, 0.20 +/- 0.22 mg/dL) and controls (-CAC, 0.19 +/- 0.21 mg/dL; P =.81) and was unrelated to the log-transformed CAC score (r < 0.01, P =.91). Multivariable analysis controlling for standard risk factors, aspirin, and statin therapy found only that low-density lipoprotein cholesterol was related to CAC.

CONCLUSIONS

Despite associations with standard and emerging cardiovascular risk factors, hsCRP is unrelated to the presence and extent of calcified subclinical atherosclerosis. This implies that CAC (a disease marker) and hsCRP (a process marker) may be complementary for the prediction of cardiovascular risk.

Correlation of coronary calcification and angiographically documented stenoses in patients with suspected coronary artery disease: results of 1,764 patients

OBJECTIVES

This study correlated the electron beam computed tomographic (EBCT) calcium scores with the results of coronary angiography in symptomatic patients in order to assess its value to predict or exclude significant coronary artery disease (CAD).

BACKGROUND

Electron beam computed tomography is a sensitive method to detect coronary calcium. However, it is unclear whether it may play a role as a filter before invasive procedures in symptomatic patients.

METHODS

A total of 1,764 patients (1,225 men and 539 women) with suspected CAD from a single center were included in our study. All patients underwent calcium screening with EBCT (C150XP Imatron) and conventional coronary angiography.

RESULTS

Fifty-six percent of men and 47% of women revealed significant coronary stenoses (> or =50%). Total exclusion of coronary calcium (14% of the study group) was associated with an extremely low probability of stenosis (<1%). With calcium scores > or =20th, > or =100th or > or =75th percentile of age groups, the sensitivity to detect stenoses decreased to 97%, 93% and 81%, respectively, in men and to 98%, 82% and 76%, respectively, in women. At the same time, the specificity increased up to 77% in men and women. There was a significant difference in coronary calcium between men and women in all age groups; however, receiver-operating characteristic curves indicated that the test can be performed with equal accuracy in all of these subgroups.

CONCLUSIONS

Calcium screening with EBCT is a highly sensitive and moderately specific test to predict stenotic disease. Exclusion of coronary calcium defines a substantial subgroup of patients, albeit symptomatic, with a very low probability of significant stenoses.

Imaging of coronary calcium: a case for electron beam computed tomography

Coronary arterial calcification has unequivocally been shown to be a marker of atherosclerosis. To date, much research interest has been generated regarding the quantification of coronary calcification by electron beam computed tomography, and how best to use such measurements to identify and predict those at greatest risk for an adverse cardiac event. This article represents an attempt to provide an objective review of the literature regarding the potential role electron beam computed tomography (EBCT) has as an accurate and cost effective screening modality for coronary arterial disease, as well as a predictor for coronary heart disease.

Lack of correlation between psychological factors and subclinical coronary artery disease

BACKGROUND

The relation between psychological variables and clinically evident coronary artery disease has been studied extensively, although the potential mechanisms of such a relation remain speculative. We studied the relation between multiple psychological variables and subclinical coronary artery disease to assess the possible role of such variables in atherogenesis.

METHODS

We conducted a prospective study of 630 consecutive consenting, active-duty U.S. Army personnel, 39 to 45 years of age, without known coronary artery disease. Each participant was assessed for depression, anxiety, somatization, hostility, and stress. Subclinical coronary artery disease was identified by electron-beam computed tomography.

RESULTS

The mean (+/-SD) age of the subjects was 42+/-2 years; 82 percent were male, and 72 percent were white. The prevalence of coronary-artery calcification was 17.6 percent (mean calcification score, 10+/-49). The prevalence of prior or current psychiatric disorders was 12.7 percent. There was no correlation between the coronary-calcification score and the scores measuring depression (r= -0.07, P=0.08), anxiety (r=-0.07, P=0.10), hostility (r=-0.07, P=0.10), or stress (r=-0.002, P=0.96). Somatization (the number and severity of durable physical symptoms) was inversely correlated with calcification scores (r=-0.12, P=0.003), even after we controlled for age and sex. In multivariate logistic-regression models, a somatization score greater than 4 (out of a possible 26) was independently associated with the absence of any coronary-artery calcification (odds ratio, 0.49; 95 percent confidence interval, 0.25 to 0.96).

CONCLUSIONS

Our data suggest that depression, anxiety, hostility, and stress are not related to coronary-artery calcification and that somatization is associated with the absence of calcification.

Electron beam tomography as an endpoint for clinical trials of antiatherosclerotic therapy

Current antiatherosclerotic therapies are highly effective and have induced a factual reduction in morbidity and mortality related to atherosclerotic disease. This makes it difficult for clinical researchers to demonstrate a further reduction in hard events. On the other hand, angiographic studies have conclusively demonstrated that coronary artery disease regression can be used as a valid surrogate endpoint. In fact, small improvements in luminal diameter stenosis corresponded to a substantial reduction in event rates. However, because coronary angiography is invasive and expensive, other surrogate endpoints may be more desirable to ascertain the effectiveness of therapy. With electron beam tomography imaging the coronary artery tree is visualized noninvasively and vascular calcification, a marker of atherosclerotic disease, is easily detected and its extent quantified. Preliminary studies have shown that this technology provides an opportunity to serially monitor the effectiveness of medical therapy for coronary artery disease at low cost and low risk for the patient.