• Comparison of Quantitative Flow Ratio and Invasive Physiology Indices in a Diverse Population at a Tertiary United States Hospital



    Quantitative flow ratio (QFR) is a technology to evaluate the coronary stenosis significance on 3-dimensional quantitative coronary angiography. The aim of this study is to evaluate and compare the QFR versus fractional flow reserve (FFR) and/or instantaneous free-wave ratio (iFR) in a US population with a fair African American population representation.

    Methods and results

    This was a retrospective, observational and single-center study that enrolled 100 patients who underwent coronary angiography. The diagnostic performance of QFR in terms of sensitivity was 0.80 (95%CI 0.64–0.97) and specificity was 0.95 (95% CI 0.90–1.00), the positive predictive value (PPV) was 0.83 (0.68–0.98), while the negative predictive value (NPV) was 0.94 (0.88–0.99). The overall accuracy was 0.91 and area under the curve (AUC) was 0.92 (95% CI 0.87–0.97).

    The R-squared was 0.54 and the Bland-Altman plot showed a bias of 0.0016 (SD 0.063) and limits of agreement (LOA): Upper LOA 0.13 and Lower LOA −0.12. In African Americans (n = 33), accuracy, AUC, sensitivity, specificity (94%; 0.90 [0.80–1.00]; 0.90 [0.71–1.00]; 0.96 [0.87–1.00], respectively) were better than those for the overall population.


    In a US-based representative population, vessel QFR accuracy and agreement with FFR as reference is high. Diagnostic performance of QFR in African Americans is also excellent.

    Author bio

    Cardiovascular Revascularization Medicine, 2021-10-01, Volume 32, Pages 1-4


    Read the full article on Science Direct: https://www.sciencedirect.com/science/article/abs/pii/S1553838921004486

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