Clinical Research
Imaging of Coronary Calcium
Coronary Calcium Score Improves Classification of Coronary Heart Disease Risk in the Elderly: The Rotterdam Study

https://doi.org/10.1016/j.jacc.2010.06.029Get rights and content
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Objectives

The purpose of this study was to examine the effect of coronary artery calcium (CAC) on the classification of 10-year hard coronary heart disease (CHD) risk and to empirically derive cut-off values of the calcium score for a general population of elderly patients.

Background

Although CAC scoring has been found to improve CHD risk prediction, there are limited data on its impact in clinical practice.

Methods

The study comprised 2,028 asymptomatic participants (age 69.6 ± 6.2 years) from the Rotterdam Study. During a median follow-up of 9.2 years, 135 hard coronary events occurred. Persons were classified into low (<10%), intermediate (10% to 20%), and high (>20%) 10-year coronary risk categories based on a Framingham refitted risk model. In a second step, the model was extended by CAC, and reclassification percentages were calculated. Cutoff values of CAC for persons in the intermediate-risk category were empirically derived based on 10-year hard CHD risk.

Results

Reclassification by means of CAC scoring was most substantial in persons initially classified as intermediate risk. In this group, 52% of men and women were reclassified, all into more accurate risk categories. CAC values above 615 or below 50 Agatston units were found appropriate to reclassify persons into high or low risk, respectively.

Conclusions

In a general population of elderly patients at intermediate CHD risk, CAC scoring is a powerful method to reclassify persons into more appropriate risk categories. Empirically derived CAC cutoff values at which persons at intermediate risk reclassified to either high or low risk were 615 and 50 Agatston units, respectively.

Key Words

coronary calcium
coronary heart disease
population-based
risk classification

Abbreviations and Acronyms

AU
Agatston units
CAC
coronary artery calcium
CHD
coronary heart disease
CRP
C-reactive protein
EBT
electron-beam tomography
FRS
Framingham risk score
HDL
high-density lipoprotein
NRI
net reclassification improvement

Cited by (0)

This study is supported by grants from the NESTORprogram for geriatric research, the Netherlands Heart Foundation(2003B179), the Netherlands Organization for Scientific Research(Vici 918.76.619), and the Municipality of Rotterdam. None of the funders had any role in design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript. The authors have reported that they have no other relationships to disclose. Drs. Elias-Smale and Proença contributed equally to this work.