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

Abstract

Background: The optimal cutoff value of fractional flow reserve (FFR) derived from coronary computed tomography angiography (FFR CT ) remains unclear. Methods: 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 CT according to different FFR CT cutoff values and FFR CT ranges with invasive FFR ≤0.80 as the reference standard. Results: 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 CT was 0.77 (interquartile range, 0.66–0.84; mean difference [invasive FFR-FFR CT ], 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 CT ≤0.80, 81%, 86%, 78%, 73%, and 89% for FFR CT ≤0.75, and 83%, 74%, 89%, 82%, and 83% for FFR CT ≤0.70, respectively. Per-vessel accuracy across the different ranges of FFR CT ≤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 CT ≤0.80 were 95%, 74%, 32%, 93%, and 100%, respectively. Setting a gray zone of FFR CT 0.71 to 0.80 provided high positive predictive value (82%; n=42/51) in the range of FFR CT ≤0.70 and high negative predictive value (94%; n=48/51) in FFR CT >0.80. Conclusions: This study suggested that referral to invasive coronary angiography should be considered individually in the range of FFR CT 0.71 to 0.80, whereas dichotomous decision could be made in FFR CT ≤0.70 and >0.80. Future prospective studies evaluating clinical outcomes are needed to establish optimal FFR CT -based diagnostic algorithm.

Verification of Coronary Computed Tomography-Derived Fractional Flow Reserve Measurement Site for Detection of Significant Coronary Artery Disease

“…Therefore, reconsideration of the measurement site for FFR CT in the present study may lead to improved diagnostic accuracy of FFR CT analysis, especially specificity and PPV. It has also been reported that reconsideration of the cut-off value of FFR CT may improve diagnostic accuracy, 19 and future large-scale studies that consider reconsideration of the measurement site or cut-off value are desirable.…”

Effect of Coronary Calcification Severity on Measurements and Diagnostic Performance of CT-FFR With Computational Fluid Dynamics: Results From CT-FFR CHINA Trial

“…It is a definite value rather than a range. The discrimination of ischemia by CT-FFR is more likely to be correct when the difference between real FFR value and the threshold of ischemia (FFR ≤ 0.8) is large ( 26 ). On the contrary, the dichotomous diagnosis is prone to be error when actual FFR is close to 0.8, even with a slight deviation of CT-FFR measurements.…”

Coronary Computed Tomography Angiography–derived Fractional Flow Reserve

“…51 Other researchers have suggested that the "gray zone" of CT-FFR should be set between 0.70 and 0.80 to improve the positive predictive value of CT-FFR. 59,60 Regardless, for patients whose CT-FFR value is in the "gray zone," more factors need to be considered to determine if revascularization is appropriate. These factors include the symptoms (especially the severity of chest pain), risk factors, the area of blood supply to the myocardium, and the results of functional testing, such as myocardial perfusion imaging, to provide the patients with the safest and most appropriate treatment (Fig.…”

“…Therefore, some scholars believe that a cutoff value of 0.75 may be more appropriate for detecting hemodynamically significant ischemia because it has higher specificity (78%) and acceptable sensitivity (86%) than the threshold of 0.80 51. Other researchers have suggested that the “gray zone” of CT-FFR should be set between 0.70 and 0.80 to improve the positive predictive value of CT-FFR 59,60. Regardless, for patients whose CT-FFR value is in the “gray zone,” more factors need to be considered to determine if revascularization is appropriate.…”