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Ekmejian A, Allahwala U, Ward M, Bhindi R. Impact of coronary disease patterns, anatomical factors, micro-vascular disease and non-coronary cardiac factors on invasive coronary physiology. Am Heart J 2023; 257:51-61. [PMID: 36509137 DOI: 10.1016/j.ahj.2022.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/22/2022] [Accepted: 12/07/2022] [Indexed: 05/11/2023]
Abstract
Invasive coronary physiology has been applied by interventional cardiologists to guide the management of coronary artery disease (CAD), with well-defined thresholds applied to determine whether CAD should be managed with optimal medical therapy (OMT) alone or OMT and percutaneous coronary intervention (PCI). There are multiple modalities in clinical use, including hyperaemic and non-hyperaemic indices. Despite endorsement in the major guidelines, there are various factors which impact and confound the readings of invasive coronary physiology, both within the coronary tree and beyond. This review article aims to summarise the mechanisms by which these factors impact invasive coronary physiology, and distinguish factors that contribute to ischaemia from confounding factors. The potential for mis-classification of ischaemic status is highlighted. Lastly, the authors identify targets for future research to improve the precision of physiology-guided management of CAD.
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Affiliation(s)
- Avedis Ekmejian
- Royal North Shore Hospital, Department of Cardiology, Sydney, NSW, Australia; University of Sydney Northern Clinical School, Sydney, NSW, Australia; Kolling Institute of Medical Research, Sydney, NSW, Australia.
| | - Usaid Allahwala
- Royal North Shore Hospital, Department of Cardiology, Sydney, NSW, Australia; University of Sydney Northern Clinical School, Sydney, NSW, Australia; Kolling Institute of Medical Research, Sydney, NSW, Australia
| | - Michael Ward
- Royal North Shore Hospital, Department of Cardiology, Sydney, NSW, Australia; University of Sydney Northern Clinical School, Sydney, NSW, Australia; Kolling Institute of Medical Research, Sydney, NSW, Australia
| | - Ravinay Bhindi
- Royal North Shore Hospital, Department of Cardiology, Sydney, NSW, Australia; University of Sydney Northern Clinical School, Sydney, NSW, Australia; Kolling Institute of Medical Research, Sydney, NSW, Australia
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Zhu XL, Pang ZY, Jiang W, Dong TY. Synergistic prognostic value of coronary distensibility index and fractional flow reserve based cCTA for major adverse cardiac events in patients with Coronary artery disease. BMC Cardiovasc Disord 2022; 22:220. [PMID: 35568818 PMCID: PMC9107240 DOI: 10.1186/s12872-022-02655-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 04/27/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Coronary distensibility index (CDI), as an early predictor of cardiovascular diseases, has the potential to complement coronary computed tomography angiography (cCTA)-derived fractional flow reserve (CT-FFR) for predicting major adverse cardiac events (MACEs). Thus, the prognostic value of CT-FFR combined with CDI for MACEs is worth exploring. METHODS Patients with a moderate or severe single left anterior descending coronary artery stenosis were included and underwent FFR and CDI analysis based on cCTA, followed up at least 1 year, and recorded MACEs. Multivariate logistic regression analysis was performed to determine independent predictors of MACEs. The area under of receiver operating characteristic (ROC) curve was used to evaluated evaluate the diagnostic performance of CT-FFR, CDI, and a combination of the two. RESULTS All the vessel-specific data were from LAD. 150 patients were analysed. 55 (37%) patients experienced MACEs during follow-up. Patients with CT-FFR ≤ 0.8 had higher percentage of MACEs compared with CT-FFR > 0.8 (56.3% vs.7.3%, p < 0.05). Patients' CDI was significantly decreased in MACEs group compared with non-MACEs group (p < 0.05). Multivariate analysis revealed that diabetes (p = 0.025), triglyceride (p = 0.015), CT-FFR ≤ 0.80 (p = 0.038), and CDI (p < 0.001) are independent predictors of MACEs. According to ROC curve analysis, CT-FFR combined CDI showed incremental diagnostic performance over CT-FFR alone for prediction of MACEs (AUC = 0.831 vs. 0.656, p = 0.0002). CONCLUSION Our study provides initial evidence that combining CDI with CT-FFR shows incremental discriminatory power for MACEs over CT-FFR alone, independent of clinical risk factors. Diabetes and triglyceride are also associated with MACEs.
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Affiliation(s)
- Xiao-Long Zhu
- Department of Medical Imaging, The First Affiliated Hospital of Hebei North University, No. 12, Changqing Road, Qiaoxi District, Zhangjiakou, 075000, Hebei, China.
| | - Zhi-Ying Pang
- Graduate School of Hebei North University, Hebei, China
| | - Wei Jiang
- The Medical Engineering Office, The First Affiliated Hospital of Hebei North University, Hebei, China
| | - Ting-Yu Dong
- Graduate School of Hebei North University, Hebei, China
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Freidoonimehr N, Chin R, Zander A, Arjomandi M. A Review on the Effect of Temporal Geometric Variations of the Coronary Arteries on the Wall Shear Stress and Pressure Drop. J Biomech Eng 2021; 144:1115053. [PMID: 34318321 DOI: 10.1115/1.4051923] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Indexed: 11/08/2022]
Abstract
Temporal variations of the coronary arteries during a cardiac cycle are defined as the superposition of the changes in the position, curvature, and torsion of the coronary artery axis markers and the variations in the lumen cross-sectional shape due to the distensible wall motion induced by the pulse pressure and contraction of the myocardium in a cardiac cycle. This review discusses whether modeling of the temporal variations of the coronary arteries is needed for the investigation of hemodynamics specifically in time-critical applications such as a clinical environment. The numerical modelings in the literature that model or disregard the temporal variations of the coronary arteries on the hemodynamic parameters are discussed. The results in the literature show that neglecting the effects of temporal geometric variations is expected to result in about 5% deviation of the time-averaged pressure drop and wall shear stress values and also about 20% deviation of the temporal variations of hemodynamic parameters, such as time-dependent wall shear stress and oscillatory shear index. This review study can be considered as a guide for future studies to outline the conditions in which temporal variations of the coronary arteries can be neglected while providing a reliable estimation of hemodynamic parameters.
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Affiliation(s)
- Navid Freidoonimehr
- School of Mechanical Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Rey Chin
- School of Mechanical Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Anthony Zander
- School of Mechanical Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Maziar Arjomandi
- School of Mechanical Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia
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Liu J, Mao B, Feng Y, Li B, Liu J, Liu Y. Closed-loop geometric multi-scale heart-coronary artery model for the numerical calculation of fractional flow reserve. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 208:106266. [PMID: 34265546 DOI: 10.1016/j.cmpb.2021.106266] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND OBJECTIVES Fractional flow reserve (FFR) is considered to be the "gold standard" for the clinical diagnosis of functional myocardial ischemia. With the development of medical imaging and computational fluid dynamics (CFD), noninvasive computation of FFR has been developed. The most representative calculation method is the noninvasive FFR derived from coronary CT angiography (FFRCT), but it cannot thoroughly simulate the real physiological structure of the cardiovascular system. In this study, we propose a noninvasive closed-loop FFR derived from coronary CT angiography (FFRCCT). METHODS The closed-loop multi-scale model includes three parts: the heart module, the coronary artery module with microcirculation structure and the systemic circulation module. The proposed structure was formed by coupling a lumped parameter model (0D) with a 3D model, such that the 0D model provides the boundary conditions for the 3D model. We enrolled 100 patients through a prospective multi-center clinical trial and calculated their FFRCCT. Then, we extracted the pressure and flow waveforms of the coronary stenosis vessels through closed-loop geometric multi-scale CFD calculations. We evaluated the accuracy of FFRCCT in diagnosing myocardial ischemia using the clinical measurement of FFR as the standard. RESULTS The results of FFRCCT calculation in all patients showed a good correlation between FFRCCT and FFR (r = 0.64, p < 0.05). The AUC (95% CI) of FFRCCT was 0.819 [0.72, 0.91]. The accuracy, specificity, sensitivity, positive predictive value and negative predictive value of FFRCCT were 86%, 95%, 62%, 86% and 83%, respectively. CONCLUSIONS The closed-loop multi-scale model proposed in this study can simulate the physiological cycle in a more realistic way. FFRCCT is a reliable diagnostic index for myocardial ischemia.
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Affiliation(s)
- Jincheng Liu
- Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China.
| | - Boyan Mao
- Beijing University of Chinese Medicine, Beijing 100029, China.
| | - Yue Feng
- Peking University First Hospital, Medical Equipment Dept, Beijing 100034, China.
| | - Bao Li
- Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China.
| | - Jian Liu
- People's Hospital, Peking University, Beijing 100080, China.
| | - Youjun Liu
- Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, China.
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Ghorbanniahassankiadeh A, Marks DS, LaDisa JF. Correlation of Computational Instantaneous Wave-Free Ratio With Fractional Flow Reserve for Intermediate Multivessel Coronary Disease. J Biomech Eng 2021; 143:1096333. [PMID: 33454732 DOI: 10.1115/1.4049746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Indexed: 01/14/2023]
Abstract
This study computationally assesses the accuracy of an instantaneous wave-free ratio (iFR) threshold range compared to standard modalities such as fractional flow reserve (FFR) and coronary flow reserve (CFR) for multiple intermediate lesions near the left main (LM) coronary bifurcation. iFR is an adenosine-independent index encouraged for assessment of coronary artery disease (CAD), but different thresholds are debated. This becomes particularly challenging in cases of multivessel disease when sensitivity to downstream lesions is unclear. Idealized LM coronary arteries with 34 different intermediate stenoses were created and categorized (Medina) as single and multiple lesion groups. Computational fluid dynamics modeling was performed with physiologic boundary conditions using an open-source software (simvascular1) to solve the time-dependent Navier-Stokes equations. A strong linear relationship between iFR and FFR was observed among studied models, indicating computational iFR values of 0.92 and 0.93 are statistically equivalent to an FFR of 0.80 in single and multiple lesion groups, respectively. At the clinical FFR value (i.e., 0.8), a triple-lesion group had smaller CFR compared to the single and double lesion groups (e.g., triple = 3.077 versus single = 3.133 and double = 3.132). In general, the effect of additional intermediate downstream lesions (minimum lumen area > 3 mm2) was not statistically significant for iFR and CFR. A computational iFR of 0.92 best predicts an FFR of 0.80 and may be recommended as threshold criteria for computational assessment of LM stenosis following additional validation using patient-specific models.
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Affiliation(s)
- Arash Ghorbanniahassankiadeh
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, 8701 W Watertown Plank Road, Milwaukee, WI 53226
| | - David S Marks
- Division of Cardiovascular Medicine, Department of Medicine, Medical College of Wisconsin, 8701 W Watertown Plank Road, Milwaukee, WI 53226
| | - John F LaDisa
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, 8701 W Watertown Plank Road, Milwaukee, WI 53226; Department of Physiology, Medical College of Wisconsin, 8701 W Watertown Plank Road, Milwaukee, WI 53226; Department of Medicine, Medical College of Wisconsin, 8701 W Watertown Plank Road, Milwaukee, WI 53226
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Impact of Malapposed and Overlapping Stents on Hemodynamics: A 2D Parametric Computational Fluid Dynamics Study. MATHEMATICS 2021. [DOI: 10.3390/math9080795] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Despite significant progress, malapposed or overlapped stents are a complication that affects daily percutaneous coronary intervention (PCI) procedures. These malapposed stents affect blood flow and create a micro re-circulatory environment. These disturbances are often associated with a change in Wall Shear Stress (WSS), Time-averaged WSS (TAWSS), relative residence time (RRT) and oscillatory character of WSS and disrupt the delicate balance of vascular biology, providing a possible source of thrombosis and restenosis. In this study, 2D axisymmetric parametric computational fluid dynamics (CFD) simulations were performed to systematically analyze the hemodynamic effects of malapposition and stent overlap for two types of stents (drug-eluting stent and a bioresorbable stent). The results of the modeling are mainly analyzed using streamlines, TAWSS, oscillatory shear index (OSI) and RRT. The risks of restenosis and thrombus are evaluated according to commonly accepted thresholds for TAWSS and OSI. The small malapposition distances (MD) cause both low TAWSS and high OSI, which are potential adverse outcomes. The region of low OSI decrease with MD. Overlap configurations produce areas with low WSS and high OSI. The affected lengths are relatively insensitive to the overlap distance. The effects of strut size are even more sensitive and adverse for overlap configurations compared to a well-applied stent.
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FENG YUE, MAO BOYAN, LI BAO, LIU JIAN, LIU JINCHENG, LIU YOUJUN. EFFECT OF HEMODYNAMIC PARAMETERS ON FRACTIONAL FLOW RESERVE. J MECH MED BIOL 2020. [DOI: 10.1142/s0219519420500177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background: The fractional flow reserve (FFR) is the gold standard used to diagnose whether coronary stenosis triggers myocardial ischemia. Myocardial ischemia is not only related to the degree of coronary artery disease but also to hemodynamic parameters such as mean arterial pressure, flow, and so on. This paper will explore the effects of hemodynamic parameters on FFR. Methods: Construct an ideal vascular model of moderately stenosis lesions (40–70%) with different hemodynamic environments. A pressure waveform was set as the inlet boundary, a microcirculation resistance in the hyperemia state was set as the outlet boundary, and different hemodynamic environments were constructed by changing the mean arterial pressure and flow at rest. The microcirculation resistance in the resting state was determined by the mean arterial pressure and flow, and the microcirculation resistance in the hyperemia state was 0.24 times than in the resting state. Results:Flow at rest was found to have the greatest impact on FFR, followed by arterial pressure. Both a decrease in flow and an increase in mean arterial pressure caused an increase in the FFR value. Conclusion:Based on the degree of stenosis of the diseased blood vessel, systolic pressure, diastolic blood pressure, and blood flow through the diseased blood vessel in the resting state, a preliminary judgment can be directly made as to whether the stenosis causes myocardial ischemia.
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Affiliation(s)
- YUE FENG
- College of Life Science and Bio-engineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing, P. R. China
| | - BOYAN MAO
- College of Life Science and Bio-engineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing, P. R. China
| | - BAO LI
- College of Life Science and Bio-engineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing, P. R. China
| | - JIAN LIU
- Cardiac Surgery Department, PeKing University People’s Hospital, 11th. South Ave. Xizhimen, Beijing, P. R. China
| | - JINCHENG LIU
- College of Life Science and Bio-engineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing, P. R. China
| | - YOUJUN LIU
- College of Life Science and Bio-engineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing, P. R. China
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Cividjian A, Harbaoui B, Chambonnet C, Bonnet J, Paquet C, Courand P, Lantelme P. Comprehensive assessment of coronary pulse wave velocity in anesthetized pigs. Physiol Rep 2020; 8:e14424. [PMID: 32400103 PMCID: PMC7218253 DOI: 10.14814/phy2.14424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Coronary stiffness represents a new paradigm for interventional cardiology and can be assessed by coronary pulse wave velocity (CoPWV). Assessing CoPWV is complex because of the coexistence of backward and forward waves. OBJECTIVES Evaluate the feasibility, repeatability, and capacity of methods assessing CoPWV to detect predictable velocity changes. METHODS CoPWV was measured from distal and proximal pressure guidewires in the left anterior descending artery of 10 pigs under general anesthesia. Four methods were studied: the tangent intersection method applied to the forward (FW) and backward (BK) waves, as well as the dicrotic notch (DIC) and template matching (TM) methods. All were evaluated at baseline, during various arterial pressure and heart rate conditions, during simulated flow limitation (balloon inflation), and after increasing coronary stiffness (stent insertion). RESULTS All the methods were significantly different between them (p ≤ .05) showing a systematic trend toward higher CoPWV when compared to the FW method (.05 < p<.10). Results were found to be significantly correlated only between the BK and FW methods and between the DIC and TM methods (p ≤ .05). CoPWV increased with arterial pressure increase, this increase being significant for the DIC and TM methods and partly for the FW method (p ≤ .05). Conversely, heart rate had no systematic impact on CoPWV. The lowest variability was found for the DIC and TM methods (p ≤ .05). Only the BK and TM methods remained applicable during flow limitation; stent increased CoPWV when measured by the BK method only (p ≤ .05). CONCLUSION Although CoPWV can be measured by various methods, the BK and TM methods seem the most appropriate for clinical studies.
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Affiliation(s)
- Andrei Cividjian
- Hospices Civils de LyonFédération de Cardiologie Croix‐Rousse ‐ Lyon‐SudLyonFrance
- Univ LyonINSA‐LyonUniversité Claude Bernard Lyon 1UJM‐Saint EtienneCNRSInsermCREATIS UMR 5220, U1206LyonFrance
- Alpha‐2 LtdLyonFrance
- i‐COR TechnologiesLyonFrance
| | - Brahim Harbaoui
- Hospices Civils de LyonFédération de Cardiologie Croix‐Rousse ‐ Lyon‐SudLyonFrance
- Univ LyonINSA‐LyonUniversité Claude Bernard Lyon 1UJM‐Saint EtienneCNRSInsermCREATIS UMR 5220, U1206LyonFrance
| | - Carole Chambonnet
- Hospices Civils de LyonFédération de Cardiologie Croix‐Rousse ‐ Lyon‐SudLyonFrance
| | | | | | - Pierre‐Yves Courand
- Hospices Civils de LyonFédération de Cardiologie Croix‐Rousse ‐ Lyon‐SudLyonFrance
- Univ LyonINSA‐LyonUniversité Claude Bernard Lyon 1UJM‐Saint EtienneCNRSInsermCREATIS UMR 5220, U1206LyonFrance
| | - Pierre Lantelme
- Hospices Civils de LyonFédération de Cardiologie Croix‐Rousse ‐ Lyon‐SudLyonFrance
- Univ LyonINSA‐LyonUniversité Claude Bernard Lyon 1UJM‐Saint EtienneCNRSInsermCREATIS UMR 5220, U1206LyonFrance
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Carson JM, Roobottom C, Alcock R, Nithiarasu P. Computational instantaneous wave-free ratio (IFR) for patient-specific coronary artery stenoses using 1D network models. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3255. [PMID: 31469943 PMCID: PMC7003475 DOI: 10.1002/cnm.3255] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/22/2019] [Accepted: 08/21/2019] [Indexed: 05/05/2023]
Abstract
In this work, we estimate the diagnostic threshold of the instantaneous wave-free ratio (iFR) through the use of a one-dimensional haemodynamic framework. To this end, we first compared the computed fractional flow reserve (cFFR) predicted from a 1D computational framework with invasive clinical measurements. The framework shows excellent promise and utilises minimal patient data from a cohort of 52 patients with a total of 66 stenoses. The diagnostic accuracy of the cFFR model was 75.76%, with a sensitivity of 71.43%, a specificity of 77.78%, a positive predictive value of 60%, and a negative predictive value of 85.37%. The validated model was then used to estimate the diagnostic threshold of iFR. The model determined a quadratic relationship between cFFR and the ciFR. The iFR diagnostic threshold was determined to be 0.8910 from a receiver operating characteristic curve that is in the range of 0.89 to 0.9 that is normally reported in clinical studies.
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Affiliation(s)
- Jason M. Carson
- Zienkiewicz Centre for Computational Engineering, College of EngineeringSwansea UniversitySwanseaUK
- Data Science Building, Swansea University Medical SchoolSwansea UniversitySwanseaUK
- HDR UK Wales and Northern IrelandHealth Data Research UKLondonUK
| | - Carl Roobottom
- Derriford Hospital and Peninsula Medical SchoolPlymouth Hospitals NHS TrustPlymouthUK
| | - Robin Alcock
- Derriford Hospital and Peninsula Medical SchoolPlymouth Hospitals NHS TrustPlymouthUK
| | - Perumal Nithiarasu
- Zienkiewicz Centre for Computational Engineering, College of EngineeringSwansea UniversitySwanseaUK
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10
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The relationship between coronary lesion characteristics and pathologic shear in human coronary arteries. Clin Biomech (Bristol, Avon) 2018; 60:177-184. [PMID: 30384262 DOI: 10.1016/j.clinbiomech.2018.10.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 10/06/2018] [Accepted: 10/26/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Pathological shear stress is associated with distinct pathogenic biological pathways relevant to coronary thrombosis and atherogenesis. Although the individual effects of lesion characteristics including stenosis severity, eccentricity and lesion length on coronary haemodynamics is known, their relative importance remains poorly understood. METHODS Computational fluid dynamics (CFD) was implemented for haemodynamic analysis of 104 coronary arteries. For each coronary artery, maximum shear stress at the site of maximal stenosis, average shear stress over the sites of maximal stenosis segment, average shear stress in the proximal segments and average shear stress in the distal segments were determined. In addition, the area of low wall shear stress (ALWSS) sites in post-stenotic regions were quantified as a proportion of the vessel segment. RESULTS With increasing stenosis severity, eccentricity and lesion length, maximal and average shear stress over the sites of maximal stenosis and ALWSS increased whereas average shear stress in the proximal segments decreased. Two-way ANCOVA analysis revealed that stenosis severity and lesion length were both independent predictors of maximum shear at the site of maximal stenosis [F (1, 104) = 10.94, P = 0.001 for diameter stenosis and F (1, 104) = 6.21, P = 0.014 for lesion length] and ALWSS [F (1, 104) = 66.10, P = 0.001 for diameter stenosis and F (1, 104) = 4.23, P = 0.047 for lesion length]. CONCLUSION Our findings demonstrate that although all lesion characteristics correlate with abnormal shear stress, only stenosis severity and lesion length are independent predictors of pathogenic physiological processes.
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11
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Javadzadegan A, Moshfegh A, Afrouzi HH, Omidi M. Magnetohydrodynamic blood flow in patients with coronary artery disease. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2018; 163:111-122. [PMID: 30119846 DOI: 10.1016/j.cmpb.2018.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 05/26/2018] [Accepted: 06/05/2018] [Indexed: 06/08/2023]
Abstract
OBJECTIVES We aim to investigate the effect of a magnetic field with varying intensities on haemodynamic perturbations in a cohort of patients with coronary artery disease. METHODS Transient computational fluid dynamics (CFD) simulations were performed in three-dimensional (3D) models of coronary arteries reconstructed from 3D quantitative coronary angiography. The effect of magnetic field on wall shear stress (WSS) derived parameters including maximum wall shear stress (MWSS) and size of regions with low wall shear stress (ALWSS) as well as length of flow recirculation zones were determined. RESULTS The results showed a substantial reduction in MWSS, ALWSS and length of flow recirculation zones in the presence of magnetic field, in particular for coronaries with moderate to severe stenoses. When the whole cohort examined, time-averaged wall shear stress (TAWSS), ALWSS and the length of flow recirculation zones in the absence of magnetic field were approximately 1.71, 4.69 and 8.46 times greater than those in the presence of magnetic field, respectively. CONCLUSION Our findings imply that an externally applied magnetic field can improve haemodynamic perturbations in human coronary arteries.
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Affiliation(s)
- Ashkan Javadzadegan
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia; ANZAC Research Institute, The University of Sydney, Sydney, NSW 2139, Australia; Concord Repatriation General Hospital, Sydney Local Health District, NSW 2139, Australia.
| | - Abouzar Moshfegh
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia; ANZAC Research Institute, The University of Sydney, Sydney, NSW 2139, Australia; Concord Repatriation General Hospital, Sydney Local Health District, NSW 2139, Australia
| | | | - Mohammad Omidi
- Faculty of Mechanical Engineering, Babol Noshirvani University of Technology, Babol, Iran
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12
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Kharche SR, So A, Salerno F, Lee TY, Ellis C, Goldman D, McIntyre CW. Computational Assessment of Blood Flow Heterogeneity in Peritoneal Dialysis Patients' Cardiac Ventricles. Front Physiol 2018; 9:511. [PMID: 29867555 PMCID: PMC5968396 DOI: 10.3389/fphys.2018.00511] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 04/20/2018] [Indexed: 01/28/2023] Open
Abstract
Dialysis prolongs life but augments cardiovascular mortality. Imaging data suggests that dialysis increases myocardial blood flow (BF) heterogeneity, but its causes remain poorly understood. A biophysical model of human coronary vasculature was used to explain the imaging observations, and highlight causes of coronary BF heterogeneity. Post-dialysis CT images from patients under control, pharmacological stress (adenosine), therapy (cooled dialysate), and adenosine and cooled dialysate conditions were obtained. The data presented disparate phenotypes. To dissect vascular mechanisms, a 3D human vasculature model based on known experimental coronary morphometry and a space filling algorithm was implemented. Steady state simulations were performed to investigate the effects of altered aortic pressure and blood vessel diameters on myocardial BF heterogeneity. Imaging showed that stress and therapy potentially increased mean and total BF, while reducing heterogeneity. BF histograms of one patient showed multi-modality. Using the model, it was found that total coronary BF increased as coronary perfusion pressure was increased. BF heterogeneity was differentially affected by large or small vessel blocking. BF heterogeneity was found to be inversely related to small blood vessel diameters. Simulation of large artery stenosis indicates that BF became heterogeneous (increase relative dispersion) and gave multi-modal histograms. The total transmural BF as well as transmural BF heterogeneity reduced due to large artery stenosis, generating large patches of very low BF regions downstream. Blocking of arteries at various orders showed that blocking larger arteries results in multi-modal BF histograms and large patches of low BF, whereas smaller artery blocking results in augmented relative dispersion and fractal dimension. Transmural heterogeneity was also affected. Finally, the effects of augmented aortic pressure in the presence of blood vessel blocking shows differential effects on BF heterogeneity as well as transmural BF. Improved aortic blood pressure may improve total BF. Stress and therapy may be effective if they dilate small vessels. A potential cause for the observed complex BF distributions (multi-modal BF histograms) may indicate existing large vessel stenosis. The intuitive BF heterogeneity methods used can be readily used in clinical studies. Further development of the model and methods will permit personalized assessment of patient BF status.
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Affiliation(s)
- Sanjay R Kharche
- Kidney Clinical Research Unit, Lawson's Health Research Institute, Victoria Hospital, London, ON, Canada.,Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Aaron So
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.,Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | - Fabio Salerno
- Kidney Clinical Research Unit, Lawson's Health Research Institute, Victoria Hospital, London, ON, Canada
| | - Ting-Yim Lee
- Robarts Research Institute, University of Western Ontario, London, ON, Canada
| | - Chris Ellis
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Daniel Goldman
- Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Christopher W McIntyre
- Kidney Clinical Research Unit, Lawson's Health Research Institute, Victoria Hospital, London, ON, Canada.,Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
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