Study of the effect of boundary conditions on fractional flow reserve using patient specific coronary phantoms

2020 ◽  
Author(s):  
Kelsey N. Sommer ◽  
Lauren M. Shepard ◽  
Vijay Iyer ◽  
Erin Angel ◽  
Michael F. Wilson ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Fractional Flow Reserve ◽  
Patient Specific ◽  
Fractional Flow ◽  
Flow Reserve

scholarly journals Impact of Inflow Boundary Conditions on the Calculation of CT-Based FFR

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 60 ◽  
Author(s):  
Ernest Lo ◽  
Leon Menezes ◽  
Ryo Torii
Keyword(s):  
Boundary Conditions ◽  
Coronary Arteries ◽  
Three Dimensional ◽  
Patient Specific ◽  
Fractional Flow ◽  
Anatomical Models ◽  
Diastolic Phase ◽  
Flow Reserve ◽  
Population Average ◽  
The Impact

Background: Calculation of fractional flow reserve (FFR) using computed tomography (CT)-based 3D anatomical models and computational fluid dynamics (CFD) has become a common method to non-invasively assess the functional severity of atherosclerotic narrowing in coronary arteries. We examined the impact of various inflow boundary conditions on computation of FFR to shed light on the requirements for inflow boundary conditions to ensure model representation. Methods: Three-dimensional anatomical models of coronary arteries for four patients with mild to severe stenosis were reconstructed from CT images. FFR and its commonly-used alternatives were derived using the models and CFD. A combination of four types of inflow boundary conditions (BC) was employed: pulsatile, steady, patient-specific and population average. Results: The maximum difference of FFR between pulsatile and steady inflow conditions was 0.02 (2.4%), approximately at a level similar to a reported uncertainty level of clinical FFR measurement (3–4%). The flow with steady BC appeared to represent well the diastolic phase of pulsatile flow, where FFR is measured. Though the difference between patient-specific and population average BCs affected the flow more, the maximum discrepancy of FFR was 0.07 (8.3%), despite the patient-specific inflow of one patient being nearly twice as the population average. Conclusions: In the patients investigated, the type of inflow boundary condition, especially flow pulsatility, does not have a significant impact on computed FFRs in narrowed coronary arteries.

A novel patient-specific model to compute coronary fractional flow reserve

2014 ◽  
Vol 116 (1) ◽  
pp. 48-55 ◽  
Author(s):  
Soon-Sung Kwon ◽  
Eui-Chul Chung ◽  
Jin-Seo Park ◽  
Gook-Tae Kim ◽  
Jun-Woo Kim ◽  
...  
Keyword(s):  
Fractional Flow Reserve ◽  
Specific Model ◽  
Patient Specific ◽  
Fractional Flow ◽  
Flow Reserve

scholarly journals The role of extra-coronary vascular conditions that affect coronary fractional flow reserve estimation.

2021 ◽  
Author(s):  
Jermiah Joseph ◽  
Daniel Goldman ◽  
Sanjay R Kharche
Keyword(s):  
Atrial Fibrillation ◽  
Fractional Flow Reserve ◽  
Microvascular Disease ◽  
Patient Specific ◽  
Fractional Flow ◽  
Reserve Estimation ◽  
Coronary Vasculature ◽  
Flow Reserve ◽  
Flow Investigation ◽  
The Right

The treatment of coronary stenosis is often based upon invasive high risk surgical assessment. The surgical assessment quantifies the fractional flow reserve (FFR), a ratio of distal to proximal pressures in respect of the stenosis. Non-invasive imaging-computational methodologies call for robust and calibrated mathematical descriptions of the coronary vasculature that can be personalized. In addition, it is important to understand non-vascular factors that FFR. In this preliminary work, a 0D coronary vasculature model capable of personalization was implemented. The model was used to demonstrate the roles of focal and extended stenosis (intra-vascular), as well as microvascular disease and atrial fibrillation (extra-vascular) on FFR. It was found that FFR the right coronary artery is maximally affected by disease conditions. Interestingly, the severity of both microvascular disease and atrial fibrillation were found to be secondary to their mere presence regarding the modelling based FFR estimation. The 0D model provides a computationally inexpensive instrument for in silico coronary blood flow investigation as well as clinical-imaging decision making. Further- more, it establishes a basis for 3D computational fluid dynamics assessment of FFR in patient specific geometries.

Assessment of Invasive Fractional Flow Reserve Procedures Using Computational Fluid Dynamics

2020 ◽  
Author(s):  
Yasser Abuouf ◽  
Muhamed Albadawi ◽  
Shinichi Ookawara ◽  
Mahmoud Ahmed
Keyword(s):  
Blood Flow ◽  
Coronary Artery ◽  
Pressure Drop ◽  
Fractional Flow Reserve ◽  
Treatment Plan ◽  
Three Dimensional ◽  
Patient Specific ◽  
Concomitant Treatment ◽  
Fractional Flow ◽  
Flow Reserve

Abstract Coronary artery disease is the abnormal contraction of heart supply blood vessel. It may lead to major consequences such as heart attack and death. This narrowing in the coronary artery limits the oxygenated blood flow to the heart. Thus, diagnosing its severity helps physicians to select the appropriate treatment plan. Fractional Flow Reserve (FFR) is one of the most accurate methods to pinpoint the stenosis severity. The advantages of FFR are high accuracy, immediate estimation of the severity of the stenosis, and concomitant treatment using balloon or stent. Nevertheless, the main disadvantage of the FFR is being an invasive procedure that requires an incision under anesthesia. Moreover, inserting the guidewire across the stenosis may result in a ‘tight-fit’ between the vessel lumen and the guidewire. This may cause an increase in the measured pressure drop, leading to a false estimation of the blood flow parameters. To estimate the errors in diagnosis procedures, a comprehensive three-dimensional model blood flow along with guidewire is developed. Reconstructed three-dimensional coronary artery geometry from a patient-specific scan is used. Blood is considered non-Newtonian and the flow is pulsatile. The comprehensive model is numerically simulated using boundary conditions. Based on the predicted results, the ratio between pressure drop and distal dynamic pressure (CDP) is studied. The predicted results for each case are compared with the control case (the case without guidewire) and analyzed. It was found that simulating the model by placing the guidewire at a full position prior to the simulation leads to an overestimation of the CDP as it increases by 34.3%. However, simulating the procedure of guidewire insertion is more accurate. It shows that the CDP value increases by 7%.

An Outflow Boundary Condition Model for Noninvasive Prediction of Fractional Flow Reserve in Diseased Coronary Arteries

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Iyad A. Fayssal ◽  
Fadl Moukalled ◽  
Samir Alam ◽  
Hussain Isma'eel
Keyword(s):  
Boundary Condition ◽  
Coronary Arteries ◽  
Fractional Flow Reserve ◽  
Physiological Parameters ◽  
Arterial System ◽  
Patient Specific ◽  
Fractional Flow ◽  
Condition Model ◽  
Flow Reserve ◽  
Boundary Condition Model

This paper reports on a new boundary condition formulation to model the total coronary myocardial flow and resistance characteristics of the myocardial vascular bed for any specific patient when considered for noninvasive diagnosis of ischemia. The developed boundary condition model gives an implicit representation of the downstream truncated coronary bed. Further, it is based on incorporating patient-specific physiological parameters that can be noninvasively extracted to account for blood flow demand to the myocardium at rest and hyperemic conditions. The model is coupled to a steady three-dimensional (3D) collocated pressure-based finite volume flow solver and used to characterize the “functional significance” of a patient diseased coronary artery segment without the need for predicting the hemodynamics of the entire arterial system. Predictions generated with this boundary condition provide a deep understanding of the inherent challenges behind noninvasive image-based diagnostic techniques when applied to human diseased coronary arteries. The overall numerical method and formulated boundary condition model are validated via two computational-based procedures and benchmarked with available measured data. The newly developed boundary condition is used via a designed computational methodology to (a) confirm the need for incorporating patient-specific physiological parameters when modeling the downstream coronary resistance, (b) explain the discrepancies presented in the literature between measured and computed fractional flow reserve (FFRCT), and (c) discuss the current limitations and future challenges in shifting to noninvasive assessment of ischemia.

scholarly journals Quantification of effects of mean blood pressure and left ventricular mass on noninvasive fast fractional flow reserve

2020 ◽  
Vol 319 (2) ◽  
pp. H360-H369
Author(s):  
Jun-Mei Zhang ◽  
Gaurav Chandola ◽  
Ru-San Tan ◽  
Ping Chai ◽  
Lynette L. S. Teo ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Left Ventricular Mass ◽  
Fractional Flow Reserve ◽  
Disease Diagnosis ◽  
Left Ventricular ◽  
Mean Blood Pressure ◽  
Patient Specific ◽  
Fractional Flow ◽  
Flow Reserve ◽  
Ventricular Mass

While brachial mean blood pressure (MBP) and left ventricular mass (LVM) measured from CTCA are the two CFD simulation input parameters, their effects on noninvasive fractional flow reserve (FFRB) have not been systematically investigated. We demonstrate that inaccurate MBP and LVM inputs differing from patient-specific values could result in misclassification of borderline ischemic lesions. This is important in the clinical application of noninvasive FFR in coronary artery disease diagnosis.

P6181The association of coronary lumen volume to left ventricle mass ratio with myocardial blood flow and fractional flow reserve

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
P A Van Diemen ◽  
S P Schumacher ◽  
M J Bom ◽  
R S Driessen ◽  
H Everaars ◽  
...  
Keyword(s):  
Blood Flow ◽  
Left Ventricle ◽  
Myocardial Blood Flow ◽  
Fractional Flow Reserve ◽  
Patient Specific ◽  
Mass Ratio ◽  
Fractional Flow ◽  
Left Ventricle Mass ◽  
Lumen Volume ◽  
Flow Reserve

Abstract Background A low coronary lumen volume to left ventricle mass ratio (V/M) derived from coronary computed tomography angiography (CCTA) has been proposed as a factor contributing to impaired myocardial blood flow (MBF) even in the absence of obstructive coronary artery disease (CAD). Objective To elucidate the association of V/M with non-invasively obtained MBF parameters by means of [15O]H2O positron emission tomography (PET), as well as its correlations with invasively measured fractional flow reserve (FFR), overall and specifically in vessel with non-obstructive CAD. Methods This is a substudy of the PACIFIC trial, in which 208 patients underwent CCTA, and [15O]H2O PET prior to invasive coronary angiography (ICA) in conjunction with 3 vessel FFR measurements. Patient specific V/M was calculated for 152 patients. Matched vessel specific hyperemic MBF (hMBF), coronary flow reserve (CFR), FFR, and patient specific V/M were available for 431 vessels. The median V/M (20.71 mm3/g) was used to divide the study population into a group with a low V/M (<20.71 mm3/g) and a high V/M (≥20.71 mm3/g). Non-obstructive CAD was defined as a ≤50% stenosis grade on ICA. Results Overall, a higher percentage of vessels with an abnormal hMBF (34% vs. 19%, p=0.009), lower FFR values (0.93 [interquartile range: 0.85–0.97] vs. 0.95 [0.89–0.98], p=0.016), and a higher number of positive FFR values (20% vs. 9%, p=0.004) were observed among vessels in the low V/M group. Furthermore, a weak correlation between V/M, global hMBF (R=0.179, p=0.027), and global CFR (R=0.163, p=0.045) as well as a weak significant association with vessel specific hMBF (p=0.027), and FFR (p<0.001) was observed (figure 1). V/M was not independently predictive of vessels specific MBF parameters or FFR. Among vessels with non-obstructive CAD (361 vessels), an abnormal hMBF tended to be more frequently observed in vessels with a low patient specific V/M (21% vs. 13%, p=0.056). Globally, there was no correlation between V/M and hMBF nor CFR. Patient specific V/M tended to be weakly associated with vessel specific hMBF (p=0.083) and was associated with FFR (p=0.027) (figure 1). Lastly, patient specific V/M tended to be independently predictive of FFR in this specific group. Conclusion Overall, vessels with an abnormal hMBF, and positive FFR measurements were more frequently observed in patients with a low V/M compared to those with a high V/M. Furthermore, V/M weakly correlated with global hMBF as well as with CFR and was associated with vessel specific hMBF and FFR. However, there was no correlation between V/M and global nor vessel specific blood flow parameters in the absence of obstructive CAD, notwithstanding a weak association of V/M with FFR within this group was noted.

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