Rationale and Objectives
The quantification of coronary calcification has established itself as a valid risk marker to predict cardiovascular events. However, data derived from cardiac multi–detector row computed tomography could demonstrate that the exclusion of coronary calcification is not synonymous with the exclusion of coronary artery disease (CAD). The aims of this retrospective analysis were to determine the prevalence of significant CAD in a symptomatic cohort with indications for invasive angiography but without coronary calcification (Agatston score 0) as assessed by multislice computed tomography and to investigate whether there were any differences in terms of risk factors between patients with and without significant CAD.
Materials and Methods
Five hundred multislice computed tomographic scans (in 371 men and 129 women) were included in the analysis. Agatston scores were determined on native scans. All patients underwent coronary angiography to detect or rule out obstructive CAD. Patients with negative calcium scoring were selected and divided into two subgroups: those without obstructive CAD and those with obstructive CAD (luminal stenoses > 50%). These subgroups were characterized in terms of clinical characteristics (age and sex) and cardiovascular risk factors (diabetes mellitus, hypertension, hyperlipoproteinemia, familial predisposition, smoking, and overweight).
Results
Sixty-one of 500 patients (12.2%) had negative calcium scores (Agatston score 0). Sixteen of these patients (26.3%, or 3.2% of the total population) had obstructive CAD according to invasive angiography. Patients with obstructive CAD were significantly older (mean age, 64 ± 9 vs 55 ± 10 years; P = .003) and were more frequently diabetic (25% vs 4%, P = .0389) than patients without obstructive CAD. There were no significant differences with regard to the other risk factors.
Conclusions
In this high-risk population, the absence of coronary calcification was not sufficient to rule out CAD. Among patients without coronary calcification, the presence of significant CAD was associated with increased age and the presence of diabetes mellitus.
Coronary artery calcification (CAC) is an independent risk factor and valid indicator for coronary artery disease (CAD). The correlation between CAC and all-cause mortality has been demonstrated in numerous studies .
Cardiac computed tomography (CT) allows calcified and noncalcified coronary plaques to be visualized noninvasively. The sensitivity to detect calcified plaques is slightly higher than the accuracy to visualize noncalcified plaques . The amount of CAC can be quantified noninvasively by electron-beam CT and multislice CT (MSCT) .
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Materials and methods
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Assessment of Cardiovascular Risk Factors
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Computed Tomographic Scanners and Computed Tomographic Examinations
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Calcium Scoring
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ICA
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Statistical Analysis
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Results
Patient Population
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Table 1
Characteristics of the Study Group
Characteristic Value Age (y) 63 ± 10 Men/women 371/129 Body mass index (kg/m 2 ) 28.0 ± 4.2 Number of risk factors 3.2 ± 1.2 Diabetes mellitus 116 (23.2%) Hypertension 361 (72.1%) Hyperlipidemia 373 (74.6%) Current or former smoking 81 (6.2%) Family history of coronary artery disease 235 (47.0%) Overweight 277 (55.4%)
Data are expressed as mean ± standard deviation or as number (percentage).
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Coronary Calcium Scoring
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Table 2
Baseline Clinical Characteristics in Patients with and without Obstructive Coronary Artery Disease
Significant CAD No Significant CAD Variable ( n = 16) ( n = 45)P Age (y) 64 ± 9 55 ± 10 .003 Men/women 11/5 25/20 NS Hypertension 13 (81.3%) 22 (48.9%) NS Body mass index (kg/m 2 ) 29.6 ± 4 28.1 ± 5 NS Diabetes mellitus 4 (25.0%) 2 (4.4%) .0389 Family history 3 (18.8%) 22 (48.9%) NS Smoking 6 (37.5%) 14 (31.1%) NS Hyperlipidemia 13 (81.3%) 28 (62.2%) NS
Data are expressed as mean ± standard deviation or as number (percentage).
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Discussion
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Risk Stratification with Coronary Calcium Scoring
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Limitations
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Conclusions
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