Hyperemic Instantaneous Wave-Free Ratio Provides the Hemodynamic Outcome for Moderate to Severe Coronary Artery Stenoses

Yoshishige Kanamori, Fumitsugu Yoshikawa, Ryuichi Aikawa


Background: The fractional flow reserve (FFR) has been established as a physiological tool for the assessment of coronary ischemia. The instantaneous wave-free ratio (iFR) is an alternative pressure-derived physiologic index from the diastolic wave-free period in stable conditions. The hyperemic iFR (h-iFR) may represent a diagnostic tool; however, its diagnostic performance is unclear. Thus, we aimed to assess the diagnostic performance of the h-iFR compared with the conventional whole-cycle FFR.

Methods: Fifty consecutive lesions, which were diagnosed as 50-75% stenosis by coronary angiography, were analyzed regarding the h-iFR and FFR during the intravenous administration of adenosine using a pressure wire. The h-iFR and FFR were calculated via automated algorithms.

Results: Twenty-two stenoses were positive (FFR ≦0.8), and 28 stenoses were negative (FFR >0.8). The slope of the regression line was 1.28 in the positive group and 1.61 in the negative group. The FFR and h-iFR values ranged from 0.64 to 0.80 (0.75±0.04) and 0.52 to 0.82 (0.66±0.07), respectively, in the positive group and 0.81 to 1.02 (0.90±0.05) and 0.69 to 1.02 (0.87±0.08), respectively, in the negative group. The means of the differences between the FFR and h-iFR were 0.027 and 0.090 in the FFR positive and negative groups, respectively.

Conclusions: The hyperemic iFR, which is calculated using the diastolic phase and exhibited a larger dynamic range than the FFR, especially in FFR-positive stenosis, may be a better physiological tool than the cardiac full-cycle FFR in the evaluation of coronary ischemia.

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Pijls NH, De Bruyne B, Peels K, Van Der Voort PH, Bonnier HJ, Bartunek J, Koolen JJ. Measurement of fractional flow reserve to assess the functional severity of coronary-artery stenoses. N Engl J Med 1996;334:1703-1708.

Pijls NH, Sels JW. Functional measurement of coronary stenosis JACC 2012;59:1045–1057.

De Bruyne B, Fearon WF, Jüni P. Fractional flow reserve-guided PCI. N Engl J Med 2015;372:95.

Tanaka N, Takazawa K, Shindo N, Kobayashi H, Teramoto T, Yamashita J, Yamashina A. Decrease of fractional flow reserve shortly after percutaneous coronary intervention. Circ J 2006;70:1327-1331.

De Bruyne B, Fearon WF, Pijls NH, Barbato E, Tonino P, Piroth Z, Jagic N, Mobius-Winckler S, Rioufol G, Witt N and others. Fractional flow reserve-guided PCI for stable coronary artery disease. N Engl J Med 2014;371:1208-1217.

Abe M, Tomiyama H, Yoshida H, Doba N. Diastolic fractional flow reserve to assess the functional severity of moderate coronary artery stenoses: comparison with fractional flow reserve and coronary flow velocity reserve. Circulation 2000;102:2365-2370.

Chalyan D, Zhang Z, Takarada S, Molloi S. End-diastolic fractional flow reserve: comparison with conventional full-cardiac cycle fractional flow reserve. Circ Cardiovasc Interv 2014;7:28-34.

Sen S, Escaned J, Malik IS, Mikhail GW, Foale RA, Mila R, Tarkin J, Petraco R, Broyd C, Jabbour R and others. Development and validation of a new adenosine-independent index of stenosis severity from coronary wave-intensity analysis: results of the ADVISE (ADenosine Vasodilator Independent Stenosis Evaluation) study. J Am Coll Cardiol 2012;59:1392-1402.

Petraco R, Escaned J, Sen S, Nijjer S, Asrress KN, Echavarria-Pinto M, Lockie T, Khawaja MZ, Cuevas C, Foin N and others. Classification performance of instantaneous wave-free ratio (iFR) and fractional flow reserve in a clinical population of intermediate coronary stenoses: results of the ADVISE registry. EuroIntervention 2013;9:91-101.

Park JJ, Petraco R, Nam CW, Doh JH, Davies J, Escaned J, Koo B. Clinical validation of the resting pressure parameters in the assessment of functionally significant coronary stenosis; results of an independent, blinded comparison with fractional flow reserve. Int J Cardiol 2013;168:4070-4075.

Tanaka N, Takazawa K, Takeda K, Aikawa M, Shindo N, Amaya K, Kobori Y, Yamashina A. Coronary flow--pressure relationship distal to epicardial stenosis. Circ J 2003;67:525-529.

Nijjer SS, Sen S, Petraco R, Mayet J, Francis DP, Davies JE. The Instantaneous wave-Free Ratio (iFR) pullback: a novel innovation using baseline physiology to optimise coronary angioplasty in tandem lesions. Cardiovasc Revasc Med 2015;16:167-171.

Gould KL. Pressure-flow characteristics of coronary stenoses in unsedated dogs at rest and during coronary vasodilation. Circ Res 1978;43:242-253.

Sen S, Asrress K, Nijjer S, Petraco R, Malik I, Foale R, Mikhail G, Foin N, Broyd C, Hadjiloizou N and others. Diagnostic classification of the instantaneous wave-free ratio is equivalent to fractional flow reserve and is not improved with adenosine administration. Results of CLARIFY (Classification Accuracy of Pressure-Only Ratios Against Indices Using Flow Study). J Am Coll Cardiol 2013;61:1409-1420.

Shewan LG, Coats AJS, Henein M. Requirements for ethical publishing in biomedical journals. International Cardiovascular Forum Journal 2015;2:2 DOI: 10.17987/icfj.v2i1.4

DOI: https://doi.org/10.17987/jatamis.v1i0.284


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Copyright (c) 2016 Yoshishige Kanamori, Fumitsugu Yoshikawa, Ryuichi Aikawa

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ISSN: 2518-6140 (on-line version)