Diagnostic Agreement of Quantitative Flow Ratio with Fractional Flow Reserve in a Latin-American Population

Purpose: Quantitative flow ratio (QFR) is a recently proposed angiographic index that allows to assess the pressure loss in coronary arteries in a similar fashion as the accepted standard fractional flow reserve (FFR). The purpose of this study was to evaluate the diagnostic performance of QFR as compared to FFR, in a Latin-American population of patients with suspected ischaemic heart disease.Methods: QFR was retrospectively derived from coronary angiograms. The association, diagnostic performance, and continuous agreement of fixed-flow QFR (fQFR) and contrast-flow QFR (cQFR) with FFR was assessed by continuous and dichotomous methods.Results: 90 vessels form 63 patients were finally included. The study comprised coronary stenoses of intermediate severity, both angiographically (diameter stenosis: 46.6 ± 12.8%) and physiologically [median FFR=0.86 (quartile 1-3, 0.76-0.89)]. The correlation of FFR with both fQFR [ρ=0.841, (95% CI: 0.767 to 0.893), p<0.001] and cQFR [ρ=0.833, (95% CI: 0.755 to 0.887), p<0.001] was strong. The diagnostic performance of cQFR was numerically better [area under the ROC curve of 0.92 (95% CI: 0.86 to 0.97, p<0.001)], with 0.80 as the optimal cQFR cut-off against FFR≤0.80. This 0.80 cQFR cut-off classified correctly 83.3% of total stenoses, with a sensitivity of 85.2% and specificity of 80.6%.Conclusions: QFR was strongly associated with FFR and exhibited a high diagnostic performance in this Latin-American population.

Diagnostic Performance of Immediate Angiography Derived Quantitative Flow Ratio In Patients After Second Generation Drug Eluting Stent And Bioresorable Scaffold Implantation

The full text of this preprint has been withdrawn by the authors due to author disagreement with the posting of the preprint. Therefore, the authors do not wish this work to be cited as a reference. Questions should be directed to the corresponding author.