Diagnostic performance of intracoronary gradient-based methods by coronary computed tomography angiography for the evaluation of physiologically significant coronary artery stenoses: a validation study with fractional flow reserve.
OBJECTIVE
We validated and compared transluminal attenuation gradient (TAG) and corrected coronary opacification (CCO) of coronary computed tomography angiography (CCTA) with invasively measured fractional flow reserve (FFR).


BACKGROUND
One of the major limitations of CCTA is the discrepancy between angiographical stenosis and ischaemia-causing stenosis. Recently two new CCTA analysis methods, TAG and CCO, have been attempted to overcome this limitation but without physiological validation.


RESULTS
We measured TAG and CCO of 97 major epicardial coronary arteries from 63 patients who underwent CCTA and followed by invasive coronary angiography and FFR. Diagnostic performance of TAG and CCO was assessed using FFR <0.80 as the reference standard. The overall diagnostic performance of TAG and CCO on a per-vessel basis was moderate and similar (c-statistic = 0.696 vs. 0.637, P = 0.29). The sensitivity, specificity, positive, and negative predictive values of TAG cut-off ≤-0.654 for FFR <0.80 were 47.5, 91.2, 79.2, and 71.2%, and those of CCO cut-off >0.063 were 65.0, 61.4, 54.2, and 71.4%. TAG showed an incremental value to the diagnostic performance of CCTA but CCO did not (c-statistic =0.726 vs. 0.809, P = 0.025; c-statistic =0.726 vs. 0.784, P = 0.09). In net reclassification improvement (NRI) analysis, addition of TAG to CCTA did not result in significant reclassification (NRI = 1.0%, P = 0.41) and addition of CCO to CCTA resulted in negative reclassification (NRI = -9.3%, P = 0.036).


CONCLUSIONS
Intracoronary attenuation-based CCTA analyses, TAG and CCO, showed moderate correlation with physiological coronary artery stenosis. The incremental value of TAG or CCO to the evaluation of haemodynamically stenosis by CCTA seemed to be limited.
Department of Medicine, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. jhchoimd@gmail.com
Jin-Ho
JH
Choi
Bon-Kwon
BK
Koo
Yeonyee E
YE
Yoon
James K
JK
Min
Young-Bin
YB
Song
Joo-Yong
JY
Hahn
Seung-Hyuk
SH
Choi
Hyeon-Cheol
HC
Gwon
Yeon Hyeon
YH
Choe
D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed