Significance of Coronary Artery Calcium in Asymptomatic Subjects
Background: Coronary calcium detected noninvasively is an attractive way to diagnose atherosclerosis before the development of symptoms. This study examines the prognostic value of coronary calcium in asymptomatic subjects with usual cardiovascular risk.
Methods and Results: In 425 asymptomatic subjects, 229 men (aged 45.1 ± 14 years) and 196 women (aged 42.7 ± 13 years), coronary calcium presence was studied by digital cinefluoroscopy. The majority (76%) had no or at most one risk factor. Subjects were followed up for 58.4 ± 12.7 months for cardiac events. Coronary calcium was present in 76 of 425 (17.9%) subjects. Cardiac events were observed in 21 subjects: 2 cardiac deaths, 7 acute myocardial infarctions, 3 coronary artery bypass grafts, 3 coronary angioplasty procedures, 3 events of unstable angina, and 10 events of stable angina pectoris. Survival curve analysis showed significant differences in all the studied end points between subjects with and those without calcium. Coronary calcium was an independent predictor of all events (3.6-fold increase, P < .008), cardiac death/myocardial infarction/revascularization (13.9-fold increase, P < .02), and stable angina (7.4-fold increase, P < .007). However, calcium did not independently predict cardiac death/myocardial infarction or acute coronary syndromes.
Conclusions: Coronary calcium in asymptomatic subjects with usual cardiovascular risk adds significant incremental information to risk factors information for the development of symptomatic coronary artery disease.
Coronary atherosclerosis is a leading cause of death in developed countries. There are increasing efforts to risk-stratify asymptomatic individuals with subclinical atherosclerosis and thereby select those individuals at highest risk for whom treatment, especially lipid-lowering, would be most cost-effective. Approaches that use cholesterol or exercise testing lack precision for the detection of preclinical coronary artery disease (CAD) in asymptomatic subjects. The use of noninvasive tests to examine vascular beds for the presence of atherosclerotic plaque with calcific deposits before the development of symptoms is an attractive way of identifying subjects at risk. However, data in asymptomatic subjects is insufficient to support an association between coronary calcium and hard events and the use of calcium screening in usual cardiovascular or low-risk asymptomatic subjects.
Detrano et al, using digital subtraction fluoroscopy for coronary calcium detection in asymptomatic but high-risk subjects, reported calcium to be an independent predictor of at least one coronary heart disease end point at one year and the number of calcified arteries to be independently associated with the incidence of coronary death or infarction at 55 months. Arad et al, using electron-beam computerized tomography (EBCT) in asymptomatic subjects, described a calcium score >100 and >160 to be associated with odds ratios of 25.8:1 and 35.4:1 for coronary events at 19 months.
There has been conflicting information regarding the incremental value of calcium detection relative to conventional risk factor assessment. The demonstration of predictive values independent of existing, less expensive methods is mandatory. Detrano et al reported that EBCT screening is not more effective than the less expensive approach that uses risk factor information in asymptomatic, predominantly male adults at high risk by conventional risk factor analysis. In contrast, Arad et al recently described a high calcium score to be associated with odds ratios of 14.3 to 20.2 for cardiac events after adjustment for risk factors.
The role of calcium detection as a screening tool in asymptomatic subjects with conventional risk factors is not yet clearly defined and must be determined on the basis of clinical events occurring in asymptomatic populations. This study sought to determine the prognostic value of coronary calcium detected by digital cinefluoroscopy for independently predicting CAD-related events in asymptomatic subjects with usual cardiovascular risk.
Background: Coronary calcium detected noninvasively is an attractive way to diagnose atherosclerosis before the development of symptoms. This study examines the prognostic value of coronary calcium in asymptomatic subjects with usual cardiovascular risk.
Methods and Results: In 425 asymptomatic subjects, 229 men (aged 45.1 ± 14 years) and 196 women (aged 42.7 ± 13 years), coronary calcium presence was studied by digital cinefluoroscopy. The majority (76%) had no or at most one risk factor. Subjects were followed up for 58.4 ± 12.7 months for cardiac events. Coronary calcium was present in 76 of 425 (17.9%) subjects. Cardiac events were observed in 21 subjects: 2 cardiac deaths, 7 acute myocardial infarctions, 3 coronary artery bypass grafts, 3 coronary angioplasty procedures, 3 events of unstable angina, and 10 events of stable angina pectoris. Survival curve analysis showed significant differences in all the studied end points between subjects with and those without calcium. Coronary calcium was an independent predictor of all events (3.6-fold increase, P < .008), cardiac death/myocardial infarction/revascularization (13.9-fold increase, P < .02), and stable angina (7.4-fold increase, P < .007). However, calcium did not independently predict cardiac death/myocardial infarction or acute coronary syndromes.
Conclusions: Coronary calcium in asymptomatic subjects with usual cardiovascular risk adds significant incremental information to risk factors information for the development of symptomatic coronary artery disease.
Coronary atherosclerosis is a leading cause of death in developed countries. There are increasing efforts to risk-stratify asymptomatic individuals with subclinical atherosclerosis and thereby select those individuals at highest risk for whom treatment, especially lipid-lowering, would be most cost-effective. Approaches that use cholesterol or exercise testing lack precision for the detection of preclinical coronary artery disease (CAD) in asymptomatic subjects. The use of noninvasive tests to examine vascular beds for the presence of atherosclerotic plaque with calcific deposits before the development of symptoms is an attractive way of identifying subjects at risk. However, data in asymptomatic subjects is insufficient to support an association between coronary calcium and hard events and the use of calcium screening in usual cardiovascular or low-risk asymptomatic subjects.
Detrano et al, using digital subtraction fluoroscopy for coronary calcium detection in asymptomatic but high-risk subjects, reported calcium to be an independent predictor of at least one coronary heart disease end point at one year and the number of calcified arteries to be independently associated with the incidence of coronary death or infarction at 55 months. Arad et al, using electron-beam computerized tomography (EBCT) in asymptomatic subjects, described a calcium score >100 and >160 to be associated with odds ratios of 25.8:1 and 35.4:1 for coronary events at 19 months.
There has been conflicting information regarding the incremental value of calcium detection relative to conventional risk factor assessment. The demonstration of predictive values independent of existing, less expensive methods is mandatory. Detrano et al reported that EBCT screening is not more effective than the less expensive approach that uses risk factor information in asymptomatic, predominantly male adults at high risk by conventional risk factor analysis. In contrast, Arad et al recently described a high calcium score to be associated with odds ratios of 14.3 to 20.2 for cardiac events after adjustment for risk factors.
The role of calcium detection as a screening tool in asymptomatic subjects with conventional risk factors is not yet clearly defined and must be determined on the basis of clinical events occurring in asymptomatic populations. This study sought to determine the prognostic value of coronary calcium detected by digital cinefluoroscopy for independently predicting CAD-related events in asymptomatic subjects with usual cardiovascular risk.
Source...