Fractional Flow Reserve, Quantitative Flow Ratio, and Instantaneous Wave-Free Ratio: Comparison of Ionising Radiation Dose - European Medical Journal

Fractional Flow Reserve, Quantitative Flow Ratio, and Instantaneous Wave-Free Ratio: Comparison of Ionising Radiation Dose

1 Mins
Interventional Cardiology
EMJ Interventional Cardiology 9.1 2021 Feature Image
*Greta Ziubryte,1,2 Gediminas Jarusevicius1,2

The authors have declared no conflicts of interest.


The authors would like to thank Prof Remigijus Žaliūnas, Head of the Department of Cardiology, Hospital of Lithuanian University of Health Sciences Kaunas Clinics, and Prof Ramūnas Unikas, Chief of the Department of Interventional Cardiology, Hospital of Lithuanian University of Health Sciences Kaunas Clinics, Lithuania, for their comprehensive support for this study.

EMJ Int Cardiol. ;9[1]:34-35. Abstract Review No. AR6.
Coronary artery disease, fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), ionising radiation, physiology assessment method, quantitative flow ratio (QFR).

Each article is made available under the terms of the Creative Commons Attribution-Non Commercial 4.0 License.


The development of interventional cardiology is inevitably associated with increased dose of ionising radiation for the physician.1 Additionally, physiology-guided myocardial revascularisation is supported by both European and American experts,2,3 but these procedures may increase the total procedure time in addition to increased dose of ionising radiation for the physician.4 Therefore, the authors aimed this study to investigate the differences in dose of ionising radiation among fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), and a novel minimally invasive FFR value computation method, quantitative flow ratio (QFR).


In total, 134 patients who have undergone coronary angiography revealing intermediate lumen stenosis of 35–75% by visual estimation and for whom FFR, QFR, or iFR measurements were performed within 2020 have been prospectively included in this single-centre study. Dose area product (DAP) and fluoroscopy time (FT) were the parameters chosen for ionising radiation dose evaluation and comparison. Additionally, patient BMI was collected for unification. Statistical analysis was performed using software package SPSS 20.0® (IBM, Armonk, New York, USA). The chosen level of significance was p<0.05. Of all included functional assessment analyses, 48 were FFRs, 28 were QFRs, and 58 were iFRs. Mean BMI did not differ among groups: FFRs: 30.07, standard deviation (SD) ±6.26; QFRs: 27.14, SD ±4.61; and iFRs 29.75, SD ±5.05; p=0.08. BMI was moderately correlated to DAP (r=0.36; p<0.001). Mean FT and DAP for FFRs were 7.13 (SD ±5.82) min and 1928.63 (SD ±2137.21) cGy·cm2, respectively; for QFRs they were 2.44 (SD ±1.12) min and 923.12 (SD ±768.47) cGy·cm2, respectively; and for iFRs they were 6.50 (SD ±3.90) min and 1605.39 (SD ±1152.59) cGy·cm2, respectively. FT was almost double in FFRs and iFRs compared to QFR (p<0.001). Compared to FFR as a reference, DAP was half in QFR (p=0.012).


Since all currently available physiology assessment methods are equally accurate, reliable, and convenient on treatment decision-making, radiation safety aspects are one of the most important issues for further studies. QFR repeatedly shows promising results in significant ionising radiation dose reduction, resulting in shorter FT and DAP, irrespective of BMI; therefore it could become the method of choice in many clinical decision-making situations.

Figure 1: A) FT and B) DAP in FFR, QFR, and iFR procedure groups.
DAP: dose area product; FFR: fractional flow reserve; FT: fluoroscopy time; iFR: instantaneous wave-free ratio; QFR: quantitative flow ratio.

Seymour M. Health impacts of radiation exposure during PCI. 2017. Available at: Last accessed: April 15 2020. Neumann FJ et al. 2018 ESC/EACTS Guidelines on myocardial revascularization. Eur Heart J. 2019;40(2):87-165. Patel MR et al. ACC/AATS/AHA/ASE/ASNC/SCAI/SCCT/STS 2017 appropriate use criteria for coronary revascularization in patients with stable ischemic heart disease: a report of the American College of Cardiology appropriate use criteria task force, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, and Society of Thoracic Surgeons. J Am Coll Cardiol. 2017;69:2212-41. Westra J et al. Diagnostic performance of quantitative flow ratio in prospective enrolled patients: an individual patient-data meta-analysis. Catheter Cardiovasc Interv. 2019;94(5):693-701.

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