Correlation between coronary computed tomographic angiography and fractional flow reserve.
BACKGROUND
Coronary CT angiography (CCTA) has become an important modality to evaluate the presence of coronary artery disease. Coronary artery stenosis of intermediate severity remains a therapeutic dilemma. Measurement of fractional flow reserve (FFR) during coronary angiography is the most established technique to determine the hemodynamic severity of a coronary artery lesion. The aim of this study was to compare CCTA with FFR.


METHODS
In 56 coronary artery stenoses (42 patients) we performed CCTA, quantitative coronary angiography and FFR. CCTA measurements included diameter stenosis (DS, %), area stenosis (AS, %), minimal lumen diameter (MLD, mm), minimal lumen area (MLA, mm(2)), lesion length (LL, mm), plaque volume (mm(3)) and burden (%).


RESULTS
FFR averaged 0.81±0.14, and 10 lesions had an abnormal FFR (<0.75). We found significant correlations between FFR and DS (r=-0.67, p<0.001), AS (r=-0.68, p<0.001), MLD (r=0.58, p<0.001), MLA (r=0.53, p<0.001), LL (r=-0.36, p=0.02), plaque volume (r=-0.36, p=0.02) and plaque burden (r=-0.59, p<0.001). By multivariate regression analysis AS and LL were the strongest determinants of an abnormal FFR. The optimal cut-off value for AS was >73% (sensitivity 90%, specificity 80%, negative predictive value 97%, and positive predictive value 50%) and for LL >10 mm (sensitivity 60% and specificity 49%).


CONCLUSIONS
This study demonstrates that quantitative CCTA is correlated to FFR. Using our CCTA criteria of abnormality, significant coronary artery stenoses can be ruled out with a high negative predictive value.
Department of Radiology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark. tskaarup@yahoo.com
Thomas Skaarup
TS
Kristensen
Thomas
T
Engstrøm
Henning
H
Kelbæk
Peter
P
von der Recke
Michael Bachmann
MB
Nielsen
Klaus Fuglsang
KF
Kofoed
D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed