Optimal Cutoff Value of Fractional Flow Reserve Derived From Coronary Computed Tomography Angiography for Predicting Hemodynamically Significant Coronary Artery Disease

<jats:sec> <jats:title>Background:</jats:title> <jats:p> The optimal cutoff value of fractional flow reserve (FFR) derived from coronary computed tomography angiography (FFR <jats:sub>CT</jats:sub> ) remains unclear. </jats:p> </jats:sec> <jats:sec> <jats:title>Methods:</jats:title> <jats:p> The current study population consisted of 93 patients with 139 vessels, who had suspected coronary artery disease by computed tomography angiography and underwent invasive FFR. We evaluated diagnostic performance of FFR <jats:sub>CT</jats:sub> according to different FFR <jats:sub>CT</jats:sub> cutoff values and FFR <jats:sub>CT</jats:sub> ranges with invasive FFR ≤0.80 as the reference standard. </jats:p> </jats:sec> <jats:sec> <jats:title>Results:</jats:title> <jats:p> In per-vessel analysis, median invasive FFR was 0.85 (interquartile range, 0.75–0.90), and 57 out of 139 vessels (41%) showed hemodynamically significant stenosis (≤0.80). Median FFR <jats:sub>CT</jats:sub> was 0.77 (interquartile range, 0.66–0.84; mean difference [invasive FFR-FFR <jats:sub>CT</jats:sub> ], 0.06±0.11). Per-vessel accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 73%, 95%, 59%, 61%, and 94% for the cutoff value of FFR <jats:sub>CT</jats:sub> ≤0.80, 81%, 86%, 78%, 73%, and 89% for FFR <jats:sub>CT</jats:sub> ≤0.75, and 83%, 74%, 89%, 82%, and 83% for FFR <jats:sub>CT</jats:sub> ≤0.70, respectively. Per-vessel accuracy across the different ranges of FFR <jats:sub>CT</jats:sub> ≤0.60, 0.61 to 0.70, 0.71 to 0.80, 0.81 to 0.90, and >0.90 with the cutoff value of FFR <jats:sub>CT</jats:sub> ≤0.80 were 95%, 74%, 32%, 93%, and 100%, respectively. Setting a gray zone of FFR <jats:sub>CT</jats:sub> 0.71 to 0.80 provided high positive predictive value (82%; n=42/51) in the range of FFR <jats:sub>CT</jats:sub> ≤0.70 and high negative predictive value (94%; n=48/51) in FFR <jats:sub>CT</jats:sub> >0.80. </jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions:</jats:title> <jats:p> This study suggested that referral to invasive coronary angiography should be considered individually in the range of FFR <jats:sub>CT</jats:sub> 0.71 to 0.80, whereas dichotomous decision could be made in FFR <jats:sub>CT</jats:sub> ≤0.70 and >0.80. Future prospective studies evaluating clinical outcomes are needed to establish optimal FFR <jats:sub>CT</jats:sub> -based diagnostic algorithm. </jats:p> </jats:sec>