QFR Versus FFR Derived From Computed Tomography for Functional Assessment of Coronary Artery Stenosis

Abstract

Objectives: The aim of this study was to compare diagnostic performance between quantitative flow ratio (QFR) derived from coronary angiography and fractional flow reserve derived from computed tomography (FFR_CT) using fractional flow reserve (FFR) as the reference standard.

Background: QFR and FFR_CT are recently developed, less invasive techniques for functional assessment of coronary artery disease.

Methods: QFR, FFR_CT, and FFR were measured in 152 patients (233 vessels) with stable coronary artery disease.

Results: QFR was highly correlated with FFR (r = 0.78; p < 0.001), whereas FFR_CT was moderately correlated with FFR (r = 0.63; p < 0.001). Both QFR and FFR_CT showed moderately good agreement with FFR, presenting small values of mean difference but large values of root mean squared deviation (FFR-QFR, 0.02 ± 0.09; FFR-FFR_CT, 0.03 ± 0.11). The sensitivity, specificity, positive predictive value, and negative predictive value of QFR ≤0.80 for predicting FFR ≤0.80 were 90%, 82%, 81%, and 90%, respectively. Those of FFR_CT ≤0.80 for predicting FFR ≤0.80 were 82%, 70%, 70%, and 82%, respectively. The diagnostic accuracy of QFR ≤0.80 for predicting FFR ≤0.80 was 85% (95% confidence interval [CI]: 81% to 89%), whereas that of FFR_CT ≤0.80 for predicting FFR ≤0.80 was 76% (95% CI: 70% to 80%).

Conclusions: QFR and FFR_CT showed significant correlation with FFR. Mismatches between QFR and FFR and between FFR_CT and FFR were frequent.

Keywords: computed tomography angiography; fractional flow reserve; quantitative coronary angiography; quantitative flow ratio.