scholarly journals The Reasons Why Fractional Flow Reserve and Instance Wave-Free Ratio are Similar Using Wave Separation Analysis

2020 ◽  
Author(s):  
Soohong Min ◽  
Gwansuk Kang ◽  
Dong-Guk Paeng ◽  
Joon Hyouk Choi
Keyword(s):  
Fractional Flow Reserve ◽  
Circulation System ◽  
Fractional Flow ◽  
Wave Separation ◽  
Flow Reserve ◽  
Stenosis Severity ◽  
The Relationship ◽  
Wedge Pressure

Abstract Background and Objectives: Fractional flow reserve(FFR) and instantaneous wave-free ratio(iFR) are the two most commonly used coronary indices of physiological stenosis severity based on pressure. To minimize the effect of wedge pressure (Pwedge), FFR is measured during hyperemia conditions, and iFR is calculated as the ratio of distal and aortic pressures (Pd/Pa) in the wave-free period. The goal of this study was to predict Pwedge using the backward wave (Pback) through wave separation analysis(WSA) and to reflect the effect of Pwedge on FFR and iFR to identify the relationship between the two indices.Methods: An in vitro circulation system was constructed to calculate Pwedge. The measurements were performed in cases with stenosis percentages of 48, 71, and 88% and with hydrostatic pressures of 10 and 30 mmHg. Then, the correlation between Pback by WSA and Pwedge was calculated. In vivo coronary flow and pressure were simultaneously measured for 11 vessels in all patients. The FFR and iFR values were reconstructed as the ratios of forward wave at distal and proximal sites during hyperemia and at rest, respectively.Results: Based on the in vitro results , the correlation between Pback and Pwedge was high(r=0.990, p<0.0001). In vivo results showed high correlations between FFR and reconstructed FFR(r=0.992, p<0.001) and between iFR and reconstructed iFR(r=0.930, p<0.001).Conclusions: Reconstructed FFR and iFR were in good agreement with conventional FFR and iFR. FFR and iFR can be expressed as the variation of trans-stenotic forward pressure, indicating that the two values are inferred from the same formula under different conditions.

scholarly journals The reasons why fractional flow reserve and instantaneous wave-free ratio are similar using wave separation analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Soohong Min ◽  
Gwansuk Kang ◽  
Dong-Guk Paeng ◽  
Joon Hyouk Choi
Keyword(s):  
Fractional Flow Reserve ◽  
Circulation System ◽  
Fractional Flow ◽  
Wave Separation ◽  
Flow Reserve ◽  
Stenosis Severity ◽  
The Relationship ◽  
Wedge Pressure

Abstract Background and objectives Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) are the two most commonly used coronary indices of physiological stenosis severity based on pressure. To minimize the effect of wedge pressure (Pwedge), FFR is measured during hyperemia conditions, and iFR is calculated as the ratio of distal and aortic pressures (Pd/Pa) in the wave-free period. The goal of this study was to predict Pwedge using the backward wave (Pback) through wave separation analysis (WSA) and to reflect the effect of Pwedge on FFR and iFR to identify the relationship between the two indices. Methods An in vitro circulation system was constructed to calculate Pwedge. The measurements were performed in cases with stenosis percentages of 48, 71, and 88% and with hydrostatic pressures of 10 and 30 mmHg. Then, the correlation between Pback by WSA and Pwedge was calculated. In vivo coronary flow and pressure were simultaneously measured for 11 vessels in all patients. The FFR and iFR values were reconstructed as the ratios of forward wave at distal and proximal sites during hyperemia and at rest, respectively. Results Based on the in vitro results, the correlation between Pback and Pwedge was high (r = 0.990, p < 0.0001). In vivo results showed high correlations between FFR and reconstructed FFR (r = 0.992, p < 0.001) and between iFR and reconstructed iFR (r = 0.930, p < 0.001). Conclusions Reconstructed FFR and iFR were in good agreement with conventional FFR and iFR. FFR and iFR can be expressed as the variation of trans-stenotic forward pressure, indicating that the two values are inferred from the same formula under different conditions.

scholarly journals A validated predictive model of coronary fractional flow reserve

2011 ◽  
Vol 9 (71) ◽  
pp. 1325-1338 ◽  
Author(s):  
Yunlong Huo ◽  
Mark Svendsen ◽  
Jenny Susana Choy ◽  
Z.-D. Zhang ◽  
Ghassan S. Kassab
Keyword(s):  
Analytical Model ◽  
Fractional Flow Reserve ◽  
Coronary Stenosis ◽  
Coronary Flow ◽  
Energy Losses ◽  
Fractional Flow ◽  
Conservation Of Energy ◽  
Flow Reserve

Myocardial fractional flow reserve (FFR), an important index of coronary stenosis, is measured by a pressure sensor guidewire. The determination of FFR, only based on the dimensions (lumen diameters and length) of stenosis and hyperaemic coronary flow with no other ad hoc parameters, is currently not possible. We propose an analytical model derived from conservation of energy, which considers various energy losses along the length of a stenosis, i.e. convective and diffusive energy losses as well as energy loss due to sudden constriction and expansion in lumen area. In vitro (constrictions were created in isolated arteries using symmetric and asymmetric tubes as well as an inflatable occluder cuff) and in vivo (constrictions were induced in coronary arteries of eight swine by an occluder cuff) experiments were used to validate the proposed analytical model. The proposed model agreed well with the experimental measurements. A least-squares fit showed a linear relation as (Δ p or FFR) experiment = a (Δ p or FFR) theory + b , where a and b were 1.08 and −1.15 mmHg ( r 2 = 0.99) for in vitro Δ p , 0.96 and 1.79 mmHg ( r 2 = 0.75) for in vivo Δ p , and 0.85 and 0.1 ( r 2 = 0.7) for FFR. Flow pulsatility and stenosis shape (e.g. eccentricity, exit angle divergence, etc.) had a negligible effect on myocardial FFR, while the entrance effect in a coronary stenosis was found to contribute significantly to the pressure drop. We present a physics-based experimentally validated analytical model of coronary stenosis, which allows prediction of FFR based on stenosis dimensions and hyperaemic coronary flow with no empirical parameters.

scholarly journals IN VIVO, IN VITRO AND IN SILICO COMPARISON OF TWO DEVICES TO MEASURE FRACTIONAL FLOW RESERVE

2018 ◽  
Vol 71 (11) ◽  
pp. A1082
Author(s):  
Stephane Carlier ◽  
Julien Saussez ◽  
Alessandro Scalia ◽  
Kamil Chodzynski ◽  
Shunji Nishio ◽  
...  
Keyword(s):  
Fractional Flow Reserve ◽  
In Silico ◽  
Fractional Flow ◽  
Flow Reserve

Fractional flow reserve in clinical practice: from wire-based invasive measurement to image-based computation

2019 ◽  
Vol 41 (34) ◽  
pp. 3271-3279 ◽  
Author(s):  
Shengxian Tu ◽  
Jelmer Westra ◽  
Julien Adjedj ◽  
Daixin Ding ◽  
Fuyou Liang ◽  
...  
Keyword(s):  
Fractional Flow Reserve ◽  
Diagnostic Methods ◽  
Functional Evaluation ◽  
Fractional Flow ◽  
Catheterization Laboratory ◽  
Flow Reserve ◽  
Pressure Wire ◽  
Stenosis Severity ◽  
Procedural Guidance ◽  
Invasive Measurement

Abstract Fractional flow reserve (FFR) and instantaneous wave-free ratio are the present standard diagnostic methods for invasive assessment of the functional significance of epicardial coronary stenosis. Despite the overall trend towards more physiology-guided revascularization, there remains a gap between guideline recommendations and the clinical adoption of functional evaluation of stenosis severity. A number of image-based approaches have been proposed to compute FFR without the use of pressure wire and induced hyperaemia. In order to better understand these emerging technologies, we sought to highlight the principles, diagnostic performance, clinical applications, practical aspects, and current challenges of computational physiology in the catheterization laboratory. Computational FFR has the potential to expand and facilitate the use of physiology for diagnosis, procedural guidance, and evaluation of therapies, with anticipated impact on resource utilization and patient outcomes.

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