Prediction of coronary events with electron beam computed tomography.

OBJECTIVES: We sought to determine the prognostic accuracy of electron beam computed tomographic (EBCT) scanning of the coronary arteries at three to four years. BACKGROUND: Coronary artery calcium scores determined by EBCT correlate with the severity of coronary artery disease. However, previous reports of the prognostic accuracy of EBCT scanning for coronary events in asymptomatic individuals are conflicting. METHODS: Asymptomatic men and women undergoing coronary EBCT completed initial and follow-up evaluations, which included past medical history, the Rose angina questionnaire and interim cardiovascular events. Reported coronary events (death, nonfatal myocardial infarction [MI] and revascularization procedures) were confirmed without knowledge of the scan results. RESULTS: Information was obtained in 1,172 (99.6%) of 1,177 eligible subjects (baseline age 53 +/- 11 years, 71% men). During an average follow-up of 3.6 years, 39 subjects sustained coronary events: three coronary deaths, 15 nonfatal MIs and 21 coronary artery revascularization procedures. The mean coronary artery calcium score was 764 +/- 935 among subjects with events as compared with 135 +/- 432 among those without events (p < 0.0001). For the prediction of all coronary events and of nonfatal MIs and deaths, the areas under the receiver-operator characteristics curve were 0.84 and 0.86, respectively, and a coronary calcium score > or =160 was associated with odds ratios of 15.8 and 22.2, respectively. The odds ratios for all events remained high (14.3 to 20.2) after adjustment for self-reported cardiovascular risk factors. CONCLUSIONS: In asymptomatic adults, EBCT of the coronary arteries predicts coronary death and nonfatal MI and the need for revascularization procedures.

Serum concentration of calcium, 1,25 vitamin D and parathyroid hormone are not correlated with coronary calcifications. An electron beam computed tomography study.

BACKGROUND: The amount of coronary artery calcification, measured using electron beam computed tomography, is correlated with the volume of coronary artery atherosclerotic plaque, the severity of stenosis by angiography, and with the likelihood of future cardiovascular events. The deposition of calcium in atherosclerotic plaques may also be influenced by determinants of calcium metabolism, thus contributing to the variance of the relation between coronary artery calcification and extent of atherosclerosis. Our objective was to determine whether this variance could be explained by differences in the parameters of calcium metabolism. DESIGN AND METHODS: We measured serum concentrations of calcium, 1,25(OH)2 vitamin D and parathyroid hormone (PTH) in 50 subjects undergoing angiography for clinical indications, and evaluated the correlations between these concentrations and calcium deposition in the coronary arteries, and the ratio of calcium deposition to extent of atherosclerosis using coronary angiography. RESULTS AND CONCLUSIONS: Serum concentrations of calcium 1,25(OH)2 vitamin D and PTH were not correlated with coronary calcification or the ratio of coronary calcification to the extent of coronary stenosis. We conclude that, in subjects undergoing coronary angiography, the variance of the relationship between coronary atherosclerosis and coronary calcium is not a result of differences in serum concentrations of calcium, 1,25(OH)2 vitamin D or PTH.

Comparison of electron beam computed tomography scanning and conventional risk factor assessment for the prediction of angiographic coronary artery disease.

OBJECTIVE: To determine whether electron beam computed tomography (CT) adds to conventional risk factor assessment in the prediction of angiographic coronary artery disease. BACKGROUND: Electron beam CT scanning can be used to predict the severity of coronary atherosclerosis, but whether it does so independently of conventional risk factors is unclear. METHODS: Electron beam CT scans were performed and conventional risk factors were measured in 290 men and women undergoing coronary arteriography for clinical indications. The association of the electron beam CT-derived coronary artery calcium score and conventional risk factors with the presence and severity of angiographically defined coronary atherosclerosis was analyzed by logistic regression and receiver-operator characteristics analysis. RESULTS: Age, the ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol and the coronary calcium score were significantly and independently associated with the presence of any coronary disease and obstructive coronary disease. In association with any coronary disease, odds ratios for age, the ratio of total cholesterol to HDL cholesterol and calcium score, highest quartile vs. lowest quartile, were 6.01 (95% confidence interval 2.87 to 12.56), 3.14 (1.56 to 6.31) and 94.08 (21.06 to 420.12), respectively. For obstructive coronary disease, highest quartile vs. lowest quartile, the respective odds ratios for age, the ratio of total cholesterol to HDL and calcium score were 3.86 (1.86 to 8.00), 4.11 (1.98 to 8.52) and 34.12 (12.67 to 91.86). Male gender was also significantly associated with any coronary disease (odds ratio 2.19, p=0.04) and obstructive coronary disease (odds ratio 2.07, p=0.04). Cigarette smoking was significantly associated with any coronary disease (odds ratio=2.74, p=0.004), and diabetes was significantly associated with obstructive disease (odds ratio 3.16, p=0.01). After adjustment for the coronary calcium score and other risk factors, it was determined that triglycerides, family history and hypertension were not significantly associated with any disease state. A coronary calcium score >80 (Agatston method) was associated with an increased likelihood of any coronary disease regardless of the number of risk factors, and a coronary calcium score > or = 170 was associated with an increased likelihood of obstructive coronary disease regardless of the number of risk factors (p < 0.001). CONCLUSIONS: Electron beam CT scanning offers improved discrimination over conventional risk factors in the identification of persons with any angiographic coronary disease or angiographic obstructive coronary disease.

Correlations between vascular calcification and atherosclerosis: a comparative electron beam CT study of the coronary and carotid arteries.

PURPOSE: Electron beam CT (EBCT)-derived coronary artery calcium scores correlate with the extent of atherosclerosis, but there is a substantial variance about the general relationship between coronary calcification and coronary atherosclerosis. The relationship between calcification and atherosclerosis may also differ in various arteries. This study was designed to evaluate whether the relation between carotid artery intima-media thickness (IMT) and carotid artery calcium could be used as a correction factor to improve the correlation between coronary calcification and coronary atherosclerosis. METHOD: We measured atherosclerosis in the coronary and carotid arteries by angiography and ultrasonography, respectively, and quantified coronary and carotid calcium deposition with EBCT in 50 subjects. The correlation between the findings in the carotid and coronary arteries was investigated. RESULTS: Coronary artery calcium score correlated with coronary angiography and with carotid calcium score. Coronary stenosis correlated with carotid IMT. There was no meaningful correlation of carotid IMT and carotid calcium. CONCLUSION: There is an intraindividual variation in the relationship of plaque mass to calcification among different vessels. The relation between carotid artery calcification and carotid IMT is not predictive of the relation between coronary artery calcification and coronary obstruction.

Relation of coronary calcium score by electron beam computed tomography to arteriographic findings in asymptomatic and symptomatic adults.

Coronary arteriography was performed on 18 asymptomatic, apparently healthy adults with elevated coronary calcium scores. To extend the range of observation to subjects with low calcium scores, arteriograms from 18 patients with exertional dyspnea and/or valvular heart disease and low calcium scores were also analyzed; these 18 patients were considered asymptomatic from the point of view of coronary artery disease (CAD). For the comparison of symptomatic and asymptomatic persons, 3 age and sex-matched symptomatic patients were also selected for each of the original 18 asymptomatic subjects. Arteriograms were analyzed by computer-assisted quantitative coronary arteriography at a remote site without knowledge of the calcium score or any other patient characteristics. In the 18 asymptomatic subjects with elevated calcium scores, the mean calcium score was 573 +/- 504 (Agatston method) and the mean worst stenosis was 45% +/- 16%. For all 36 patients without symptoms of CAD, worst stenosis was closely correlated with the square root of the calcium score (r = 0.85, p <0.0001). Patients with symptomatic coronary disease and calcium scores < 1,000 had stenoses more severe than asymptomatic persons with similar calcium scores. Most asymptomatic adults with elevated calcium scores have nontrivial, nonobstructive CAD or preclinical obstructive CAD, and the relation between coronary calcium score and severity of stenosis is highly significant. These data indicate that electron beam tomography can be used to estimate the severity of CAD in asymptomatic persons.

Predictive value of electron beam computed tomography of the coronary arteries. 19-month follow-up of 1173 asymptomatic subjects.

BACKGROUND: Coronary electron beam computed tomography (EBCT) detects atherosclerotic coronary artery disease by measuring calcium deposition in the walls of coronary arteries. EBCT-derived coronary artery calcium (CAC) scores correlate with the severity of underlying coronary artery disease. METHODS AND RESULTS: We followed 1173 asymptomatic patients who underwent EBCT between September 1993 and March 1994. During average follow-up of 19 months, 18 subjects had 26 cardiovascular events: 1 death, 7 myocardial infarctions, 8 coronary artery bypass graft procedures, 9 coronary angioplasties, and 1 nonhemorrhagic stroke. For CAC score thresholds of 100, 160, and 680, EBCT had sensitivities of 89%, 89%, and 50% and specificities of 77%, 82%, and 95%, respectively. Odds ratios ranged from 20.0 to 35.4 (P < .0001 for all). CONCLUSIONS: Coronary EBCT predicts future atherosclerotic cardiovascular disease events in asymptomatic subjects.