Abstract 14186: Non-invasive Fractional Flow Reserve derived from CCTA can determine the Functional Significance of Intermediate Coronary Artery Stenosis: results from the prospective multicenter DISCOVER-FLOW study
Background: Coronary artery stenosis of intermediate severity poses a diagnostic challenge as a number of such lesions are causal of ischemia while others are not. Computational fluid dynamics (CFD) applied to coronary CT angiograms (CCTA) provides a novel non-invasive meth¬od for calculation of lesion-specific fractional flow reserve (FFRCT), but the diagnostic performance of FFRCT for intermediate stenosis has not yet been evaluated.
Methods: We determined the diagnostic performance of FFRCT derived from CCTA for the diagnosis of lesion-specific ischemia in patients with intermediate coronary stenosis as determined by quantitative coronary angiography (QCA). At 4 institutions, FFR was performed on 159 vessels in 103 patients who underwent both CCTA and invasive coronary angiography (ICA). QCA identified 68/159 (47%) vessels as having 40-69% stenosis. Non-invasive FFRCT was derived from typically-acquired CCTA images using CFD, without additional image acquisition or medication administration. Independent blinded core laboratories determined QCA, stenosis severity by CCTA and FFRCT. Lesion-specific ischemia was defined by measured FFR or FFRCT ≤0.80, and lesions ≥50% stenosis were considered obstructive by CCTA.
Results: Among the 68 vessels with intermediate stenosis (38 LAD, 21 LCx and 9 RCA), 32 (47%) were identified as ischemic by FFR ≤0.80. FFRCT identified 29 (91%) of these lesions as correctly ischemic. Compared to CCTA alone, FFRCT had a four-fold reduction in false positives (28 to 6) and a four-fold increase in true negatives (8 to 30). For the diagnosis of lesion-specific ischemia, diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value for FFRCT were 86.8%, 90.6%, 83.3%, 82.9% and 90.9% as compared to 54.4%, 90.6%, 22.2%, 50.9% and 72.7% for CCTA stenosis alone.
Conclusions: In this prospective multicenter study, non-invasive FFRCT improved the specificity for the detection of ischemia in coronary lesions with intermediate stenosis severity while maintaining high sensitivity. The addition of FFRCT to CCTA should be considered in evaluating such lesions.
- © 2011 by American Heart Association, Inc.