Comparison of quantitative flow ratio and invasive physiology indices in a diverse population at a tertiary United States hospital.

Abstract Background 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 which 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 NPV was 0.94 (0.88–0.99). The overall accuracy was 0.91 and area under 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. Conclusions 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.