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Title Correlation of Quantitative Flow Ratio assessment against instantaneous wave-free ratio in hemodynamic evaluation of coronary lesions |
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Type Free Paper Session 1 |
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Theme ACC Asia & SCS 32nd Annual Scientific Meeting |
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Topic Invasive Diagnostic & Interventional Cardiology |
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Main Author Ki Fung Cliff Li1 |
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Presenting Author Ki Fung Cliff Li1 |
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Co-Author Paul Ong1 Jason Chuang1 |
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Department / Institution / Country Cardiology / Tan Tock Seng Hospital / Singapore1 |
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Objective(s) Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are tools to assess hemodynamic significance of coronary lesions (CL). The angiographic 3D Quantitative Flow Ratio (QFR) assessment has been compared with FFR with good correlation. This is the first report on QFR benchmarked against iFR in South East Asian patients. |
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Material and Method Our study included 26 coronary vessels with iFR done (69% LAD; 7% Diagonal branch; 7% LCx; RCA 15%) from 23 patients (aged 59±9; 69% male; 39% diabetes; 73% hypertension; 87% hyperlipidemia; 13% smoker), of which 39% presented with acute coronary syndrome (55% was done for non-culprit vessels in STEMI, 22% NSTEMI). QFR of these vessels were analysed offline after anonymisation and in a blinded manner with QAngio XA 3D software (Medis Medical Imaging). |
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Result(s) Comparison between iFR and fQFR was done via Pearsons bivariate analysis, and correlation coefficient of 0.627 was statistically significant, p = 0.001. The results were plotted on a scatter plot with a general linear relationship. There was only 1 outlier on scatterplot. When the cut-off for QFR was set at <0.80 and iFR ≤0.89, there were 3 results that were positive for iFR but negative for QFR. However, when the QFR threshold was set at <0.85 instead, there was no CL with positive iFR. |
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Conclusion From our results, QFR has a good correlation with iFR. It is effective as a “gatekeeper” for further invasive pressure wire assessment with iFR, with a high negative predictive value when QFR threshold is set at 0.85. This is in line with the study by Yazaki et al which showed wide variation in agreement between QFR and FFR when QFR is approximately 0.80. We thus propose a hybrid approach in CL assessment, performing iFR only when QFR ≤0.85 . This might be a cost-effective way to assess CL in resource poor countries. |