Added value of coronary artery calcium score as an adjunct to gated SPECT for the evaluation of coronary artery disease in an intermediate-risk population.
The coronary artery calcium (CAC) score is a readily and widely available tool for the noninvasive diagnosis of atherosclerotic coronary artery disease (CAD). The aim of this study was to investigate the added value of the CAC score as an adjunct to gated SPECT for the assessment of CAD in an intermediate-risk population.


METHODS
Seventy-seven prospectively recruited patients with intermediate risk (as determined by the Framingham Heart Study 10-y CAD risk score) and referred for coronary angiography because of suspected CAD underwent stress (99m)Tc-tetrofosmin SPECT myocardial perfusion imaging (MPI) and CT CAC scoring within 2 wk before coronary angiography. The sensitivity and specificity of SPECT alone and of the combination of the 2 methods (SPECT plus CAC score) in demonstrating significant CAD (>/=50% stenosis on coronary angiography) were compared.


RESULTS
Forty-two (55%) of the 77 patients had CAD on coronary angiography, and 35 (45%) had abnormal SPECT results. The CAC score was significantly higher in subjects with perfusion abnormalities than in those who had normal SPECT results (889 +/- 836 [mean +/- SD] vs. 286 +/- 335; P < 0.0001). Similarly, with rising CAC scores, a larger percentage of patients had CAD. Receiver-operating-characteristic analysis showed that a CAC score of greater than or equal to 709 was the optimal cutoff for detecting CAD missed by SPECT. SPECT alone had a sensitivity and a specificity for the detection of significant CAD of 76% and 91%, respectively. Combining SPECT with the CAC score (at a cutoff of 709) improved the sensitivity of SPECT (from 76% to 86%) for the detection of CAD, in association with a nonsignificant decrease in specificity (from 91% to 86%).


CONCLUSIONS
The CAC score may offer incremental diagnostic information over SPECT data for identifying patients with significant CAD and negative MPI results.
Schepis
Tiziano
T
Cardiovascular Center, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland.
Gaemperli
Oliver
O
Koepfli
Pascal
P
Namdar
Mehdi
M
Valenta
Ines
I
Scheffel
Hans
H
Leschka
Sebastian
S
Husmann
Lars
L
Eberli
Franz R
FR
Luscher
Thomas F
TF
Alkadhi
Hatem
H
Kaufmann
Philipp A
PA
D000368:Aged; D002118:Calcium / Q000097:blood*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000378:metabolism*; D005260:Female; D015637:Gated Blood-Pool Imaging / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods