Repeatability of fractional flow reserve despite variations in systemic and coronary hemodynamics

Johnson, N.P., Johnson, D.T., Kirkeeide, R.L., Berry, C. , De Bruyne, B., Fearon, W.F., Oldroyd, K.G., Pijls, N.H.J. and Gould, K.L. (2015) Repeatability of fractional flow reserve despite variations in systemic and coronary hemodynamics. JACC: Cardiovascular Interventions, 8(8), pp. 1018-1027. (doi:10.1016/j.jcin.2015.01.039)

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Objectives This study classified and quantified the variation in fractional flow reserve (FFR) due to fluctuations in systemic and coronary hemodynamics during intravenous adenosine infusion. Background Although FFR has become a key invasive tool to guide treatment, questions remain regarding its repeatability and stability during intravenous adenosine infusion because of systemic effects that can alter driving pressure and heart rate. Methods We reanalyzed data from the VERIFY (VERification of Instantaneous Wave-Free Ratio and Fractional Flow Reserve for the Assessment of Coronary Artery Stenosis Severity in EverydaY Practice) study, which enrolled consecutive patients who were infused with intravenous adenosine at 140 μg/kg/min and measured FFR twice. Raw phasic pressure tracings from the aorta (Pa) and distal coronary artery (Pd) were transformed into moving averages of Pd/Pa. Visual analysis grouped Pd/Pa curves into patterns of similar response. Quantitative analysis of the Pd/Pa curves identified the “smart minimum” FFR using a novel algorithm, which was compared with human core laboratory analysis. Results A total of 190 complete pairs came from 206 patients after exclusions. Visual analysis revealed 3 Pd/Pa patterns: “classic” (sigmoid) in 57%, “humped” (sigmoid with superimposed bumps of varying height) in 39%, and “unusual” (no pattern) in 4%. The Pd/Pa pattern repeated itself in 67% of patient pairs. Despite variability of Pd/Pa during the hyperemic period, the “smart minimum” FFR demonstrated excellent repeatability (bias −0.001, SD 0.018, paired p = 0.93, r2 = 98.2%, coefficient of variation = 2.5%). Our algorithm produced FFR values not significantly different from human core laboratory analysis (paired p = 0.43 vs. VERIFY; p = 0.34 vs. RESOLVE). Conclusions Intravenous adenosine produced 3 general patterns of Pd/Pa response, with associated variability in aortic and coronary pressure and heart rate during the hyperemic period. Nevertheless, FFR – when chosen appropriately – proved to be a highly reproducible value. Therefore, operators can confidently select the “smart minimum” FFR for patient care. Our results suggest that this selection process can be automated, yet comparable to human core laboratory analysis.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Oldroyd, Dr Keith and Berry, Professor Colin
Authors: Johnson, N.P., Johnson, D.T., Kirkeeide, R.L., Berry, C., De Bruyne, B., Fearon, W.F., Oldroyd, K.G., Pijls, N.H.J., and Gould, K.L.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
Journal Name:JACC: Cardiovascular Interventions
ISSN (Online):1876-7605
Copyright Holders:Copyright © 2015 Elsevier Ltd.
First Published:First published in JACC: Cardiovascular Interventions 8(8):1018-1027
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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