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Jeong JH, Lee B, Hong J, Min C, Persad AR, Yang TH, Park YH. Cardiovascular hardware simulator and artificial aorta-generated central blood pressure waveform database according to various vascular ages for cardiovascular health monitoring applications. Comput Biol Med 2024; 172:108224. [PMID: 38460314 DOI: 10.1016/j.compbiomed.2024.108224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/11/2024] [Accepted: 02/25/2024] [Indexed: 03/11/2024]
Abstract
This study presents a database of central blood pressure waveforms according to cardiovascular health conditions, to supplement the lack of clinical data in cardiovascular health research, constructed by a cardiovascular simulator. Blood pressure (BP) is the most frequently measured biomarker, and in addition to systolic and diastolic pressure, its waveform represents the various conditions of cardiovascular health. A BP waveform is formed by overlapping the forward and reflected waves, which are affected by the pulse wave velocity (PWV). The increase in vascular stiffness with aging increases PWV, and the PWV-age distribution curve is called vascular age. For cardiovascular health research, extensive data of central BP waveform is essential, but the clinical data published so far are insufficient and imbalanced in quantity and quality. This study reproduces the central BP waveform using a cardiovascular hardware simulator and artificial aortas, which mimic the physiological structure and properties of the human. The simulator can adjust cardiovascular health conditions to the same level as humans, such as heart rate of 40-100 BPM, stroke volume of 40-100 mL, and peripheral resistance of 12 steps. Also, 6 artificial aortas with vascular ages in the 20-70 were fabricated to reproduce the increase in vascular stiffness due to aging. Vascular age calculated from measured stiffness of artificial aorta and central BP waveform showed an error of less than 3 years from the clinical value. Through this, a total of 636 waveforms were created to construct a central BP waveform database according to controlled various cardiovascular health conditions.
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Affiliation(s)
- Jae-Hak Jeong
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
| | - Bomi Lee
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
| | - Junki Hong
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
| | - Changhee Min
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
| | - Adelle Ria Persad
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
| | - Tae-Heon Yang
- Department of Mechanical and Aerospace Engineering, Konkuk University, Seoul, 05029, South Korea.
| | - Yong-Hwa Park
- Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
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Agrafiotis E, Zimpfer D, Mächler H, Holzapfel GA. Review of Systemic Mock Circulation Loops for Evaluation of Implantable Cardiovascular Devices and Biological Tissues. J Endovasc Ther 2024:15266028241235876. [PMID: 38528650 DOI: 10.1177/15266028241235876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
CLINICAL IMPACT On needs-based ex vivo monitoring of implantable devices or tissues/organs in cardiovascular simulators provides new insights and paves new paths for device prototypes. The insights gained could not only support the needs of patients, but also inform engineers, scientists and clinicians about undiscovered aspects of diseases (during routine monitoring). We analyze seminal and current work and highlight a variety of opportunities for developing preclinical tools that would improve strategies for future implantable devices. Holistically, mock circulation loop studies can bridge the gap between in vivo and in vitro approaches, as well as clinical and laboratory settings, in a mutually beneficial manner.
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Affiliation(s)
| | - Daniel Zimpfer
- Division of Cardiac Surgery, Medical University of Graz, Graz, Austria
| | - Heinrich Mächler
- Division of Cardiac Surgery, Medical University of Graz, Graz, Austria
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Graz, Austria
- Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, Norway
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3
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Elbadawi A, Sedhom R, Ghoweba M, Etewa AM, Kayani W, Rahman F. Contemporary Use of Coronary Physiology in Cardiology. Cardiol Ther 2023; 12:589-614. [PMID: 37668939 DOI: 10.1007/s40119-023-00329-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 08/11/2023] [Indexed: 09/06/2023] Open
Abstract
Coronary angiography has a limited ability to predict the functional significance of intermediate coronary lesions. Hence, physiological assessment of coronary lesions, via fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR), has been introduced to determine their functional significance. An accumulating body of evidence has consolidated the role of physiology-guided revascularization, particularly among patients with stable ischemic heart disease. The use of FFR or iFR to guide decision-making in patients with stable ischemic heart disease and intermediate coronary lesions received a class I recommendation from major societal guidelines. Nevertheless, the role of coronary physiology testing is less clear among certain patients' groups, including patients with serial coronary lesions, acute coronary syndromes, aortic stenosis, heart failure, as well as post-percutaneous coronary interventions. In this review, we aimed to discuss the utility and clinical evidence of coronary physiology (mainly FFR and iFR), with emphasis on those specific patient groups.
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Affiliation(s)
- Ayman Elbadawi
- Division of Cardiology, Christus Good Shepherd, 707 East Marshall Avenue, Longview, TX, 75604, USA.
| | - Ramy Sedhom
- Department of Internal Medicine, Einstein Medical Centre, Philadelphia, PA, USA
| | - Mohamed Ghoweba
- Department of Internal Medicine, Christus Good Shepherd, Longview, TX, 75601, USA
| | | | - Waleed Kayani
- Section of Cardiology, Baylor College of Medicine, Houston, TX, USA
| | - Faisal Rahman
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Campitelli R, Ferrario M, Su F, Creteur J, Herpain A, Carrara M. Pulse wave analysis as a tool for the evaluation of resuscitation therapy in septic shock. Physiol Meas 2023; 44:105002. [PMID: 37738987 DOI: 10.1088/1361-6579/acfc94] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/22/2023] [Indexed: 09/24/2023]
Abstract
Objective. Pulse wave analysis (PWA) can provide insights into cardiovascular biomechanical properties. The use of PWA in critically ill patients, such as septic shock patients, is still limited, but it can provide complementary information on the cardiovascular effects of treatment when compared to standard indices outlined in international guidelines. Previous works have highlighted how sepsis induces severe cardiovascular derangement with altered arterial blood pressure waveform morphology and how resuscitation according to standard haemodynamic targets is not able to restore the physiological functioning of the cardiovascular system. The aim of this work is to test the effectiveness of PWA in characterizing arterial waveforms obtained from a swine experiment involving polymicrobial septic shock and resuscitation with different drugs.Methods. During the experiment, morphological aortic waveform features, such as indices related to the dicrotic notch and inflection point, were extracted by means of PWA techniques. Finally, all the PWA indices were used to compute a clustering classification (mini batch K-means) of the pigs according to the different phases of the experiment. This analysis aimed to test if PWA features alone could be used to distinguish between the different responses to the administered therapies.Results. The PWA indices highlighted different cardiovascular conditions of the pigs in response to different treatments, despite the mean haemodynamic values typically used to guide therapy administration being similar in all animals. The clustering algorithm was able to distinguish between the different phases of the experiment and the different responses of the animals based on the unique information derived from the aortic PWA.Conclusion. Even when used alone, PWA indices were highly informative when assessing therapy responses in cases of septic shock.Significance. A complex pathological condition like septic shock requires extensive monitoring without neglecting important information from commonly measured signals such as arterial blood pressure. Future studies are needed to understand how individual differences in the response to therapy are associated with different cardiovascular conditions that may become specific therapy targets.
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Affiliation(s)
- Riccardo Campitelli
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Manuela Ferrario
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
| | - Fuhong Su
- Experimental Laboratory of Intensive Care, Université Libre de Bruxelles, Brussels, Belgium
- Department of Intensive Care, Erasme Hospital, ULB, Brussels, Belgium
| | - Jacques Creteur
- Experimental Laboratory of Intensive Care, Université Libre de Bruxelles, Brussels, Belgium
- Department of Intensive Care, Erasme Hospital, ULB, Brussels, Belgium
| | - Antoine Herpain
- Experimental Laboratory of Intensive Care, Université Libre de Bruxelles, Brussels, Belgium
- Intensive care department, St-Pierre University Hospital, Brussels, Belgium
| | - Marta Carrara
- Department of Electronics, Information, and Bioengineering, Politecnico di Milano, Milan, Italy
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5
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Wang X, Li L, Zhao Y, Tan W, Huo Y. The Interplay of Cardiac Dysfunctions and Hemodynamic Impairments During the Progression of Myocardial Infarction in Male Rats. J Biomech 2022; 142:111237. [DOI: 10.1016/j.jbiomech.2022.111237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 07/18/2022] [Accepted: 07/27/2022] [Indexed: 10/16/2022]
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Zhou S, Yao Y, Liu W, Yang J, Wang J, Hao L, Wang L, Xu L, Avolio A. Ultrasound-based method for individualized estimation of central aortic blood pressure from flow velocity and diameter. Comput Biol Med 2022; 143:105254. [PMID: 35093843 DOI: 10.1016/j.compbiomed.2022.105254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/10/2022] [Accepted: 01/20/2022] [Indexed: 11/16/2022]
Abstract
Central aortic blood pressure (CABP) is a better predictor for cardiovascular events than brachial blood pressure. However, direct CABP measurement is invasive. The objective of this paper is to develop an ultrasound-based method using individualized Windkessel (WK) models for non-invasive estimation of CABP. Three WK models (with two-, three- and four-element WK, named, WK2, WK3 and WK4, respectively) were created and the model parameters were individualized based on aortic flow velocity and diameter waveforms measured by ultrasound (US). Experimental data were acquired in 42 subjects aged 21-67 years. The CABP estimated by WK models was compared with the reference CABP obtained using a commercial system. The results showed that the overall performance of the WK3 and WK4 models was similar, outperforming the WK2 model. The estimated CABP based on WK3/WK4 model showed good agreement with the reference CABP: the absolute errors of systolic blood pressure (SBP), 2.4 ± 2.1/2.4 ± 2.0 mmHg; diastolic blood pressure (DBP), 1.4 ± 1.1/1.7 ± 1.5 mmHg; mean blood pressure (MBP), 1.3 ± 0.8/1.3 ± 0.8 mmHg; pulse pressure (PP), 3.0 ± 2.3/3.2 ± 2.6 mmHg; the root mean square error (RMSE) of the waveforms, 2.5 ± 1.0/2.6 ± 1.1 mmHg. Therefore, the proposed method can provide a non-invasive CABP estimation during routine cardiac US examination.
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Affiliation(s)
- Shuran Zhou
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China
| | - Yang Yao
- School of Information Science and Technology, Shanghai Tech University, Shanghai, 201210, China
| | - Wenyan Liu
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China
| | - Jun Yang
- The First Hospital of China Medical University, Shenyang, 110122, China
| | - Junli Wang
- The First Hospital of China Medical University, Shenyang, 110122, China
| | - Liling Hao
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China
| | - Lu Wang
- School of Computer Science and Engineering, Northeastern University, Shenyang, 110169, China
| | - Lisheng Xu
- College of Medicine and Biological Information Engineering, Northeastern University, Shenyang, 110169, China; Engineering Research Center of Medical Imaging and Intelligent Analysis, Ministry of Education, Shenyang, 110169, China; Neusoft Research of Intelligent Healthcare Technology, Co. Ltd., Shenyang, 110169, China.
| | - Alberto Avolio
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, 2109, New South Wales, Australia
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Paré M, Goupil R, Fortier C, Mac-Way F, Madore F, Hametner B, Wassertheurer S, Schultz MG, Sharman JE, Agharazii M. Increased Excess Pressure After Creation of an Arteriovenous Fistula in End-Stage Renal Disease. Am J Hypertens 2022; 35:149-155. [PMID: 34655294 PMCID: PMC8807157 DOI: 10.1093/ajh/hpab161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 09/12/2021] [Accepted: 10/14/2021] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Reservoir-wave analysis (RWA) separates the arterial waveform into reservoir and excess pressure (XSP) components, where XSP is analogous to flow and related to left ventricular workload. RWA provides more detailed information about the arterial tree than traditional blood pressure (BP) parameters. In end-stage renal disease (ESRD), we have previously shown that XSP is associated with increased mortality and is higher in patients with arteriovenous fistula (AVF). In this study, we examined whether XSP increases after creation of an AVF in ESRD. METHODS Before and after a mean of 3.9 ± 1.2 months following creation of AVF, carotid pressure waves were recorded using arterial tonometry. XSP and its integral (XSPI) were derived using RWA through pressure wave analysis alone. Aortic stiffness was assessed by carotid-femoral pulse wave velocity (CF-PWV). RESURLTS In 38 patients (63% male, age 59 ± 15 years), after AVF creation, brachial diastolic BP decreased (79 ± 10 vs. 72 ± 12 mm Hg, P = 0.002), but the reduction in systolic BP, was not statistically significant (133 ± 20 vs. 127 ± 26 mm Hg, P = 0.137). However, carotid XSP (14 [12-19] to 17 [12-22] mm Hg, P = 0.031) and XSPI increased significantly (275 [212-335] to 334 [241-439] kPa∙s, P = 0.015), despite a reduction in CF-PWV (13 ± 3.6 vs. 12 ± 3.5 m/s, P = 0.025). CONCLUSIONS Creation of an AVF resulted in increased XSP in this population, despite improvement in diastolic BP and aortic stiffness. These findings underline the complex hemodynamic impact of AVF on the cardiovascular system.
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Affiliation(s)
- Mathilde Paré
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Québec City, Québec, Canada
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Université Laval, Québec, Québec, Canada
| | - Rémi Goupil
- Hôpital du Sacré-Cœur de Montréal, Department of Medicine, Montréal, Québec, Canada
| | - Catherine Fortier
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Québec City, Québec, Canada
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Université Laval, Québec, Québec, Canada
- INSERM-U970-Paris Cardiovascular Research Center (PARCC), Paris, France
| | - Fabrice Mac-Way
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Québec City, Québec, Canada
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Université Laval, Québec, Québec, Canada
| | - François Madore
- Hôpital du Sacré-Cœur de Montréal, Department of Medicine, Montréal, Québec, Canada
| | - Bernhard Hametner
- Center for Health & Bioresources, Department of Health and Environment, AIT Austrian Institute of Technology, Vienna, Austria
| | - Siegfried Wassertheurer
- Center for Health & Bioresources, Department of Health and Environment, AIT Austrian Institute of Technology, Vienna, Austria
| | - Martin G Schultz
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - James E Sharman
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Mohsen Agharazii
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Québec City, Québec, Canada
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Université Laval, Québec, Québec, Canada
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Jonášová A, Vimmr J. On the relevance of boundary conditions and viscosity models in blood flow simulations in patient-specific aorto-coronary bypass models. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3439. [PMID: 33464717 DOI: 10.1002/cnm.3439] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/11/2021] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Physiologically realistic results are the aim of every blood flow simulation. This is not different in aorto-coronary bypasses where the properties of the coronary circulation may significantly affect the relevance of the performed simulations. By considering three patient-specific bypass geometries, the present article focuses on two aspects of the coronary blood flow - its phasic flow pattern and its behaviour affected by blood rheology. For the phasic flow property, a multiscale modelling approach is chosen as a means to assess the ability of five different types of coronary boundary conditions (mean arterial pressure, Windkessel model and three lumped parameter models) to attain realistic coronary haemodynamics. From the analysed variants of boundary conditions, the best option in terms of physiological characteristics and its potential for use in patient-based simulations, is utilised to account for the effect of shear-dependent viscosity on the resulting haemodynamics and wall shear stress stimulation. Aside from the Newtonian model, the blood rheology is approximated by two non-Newtonian models in order to determine whether the choice of a viscosity model is important in simulations involving coronary circulation. A comprehensive analysis of obtained results demonstrated notable superiority of all lumped parameter models, especially in comparison to the constant outlet pressure, which regardless of bypass type gave overestimated and physiologically misleading results. In terms of rheology, it was noted that blood in undamaged coronary arteries behaves as a Newtonian fluid, whereas in vessels with atypical lumen geometry, such as that of anastomosis or stenosis, its shear-thinning behaviour should not be ignored.
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Affiliation(s)
- Alena Jonášová
- NTIS - New Technologies for the Information Society, Faculty of Applied Sciences, University of West Bohemia, Plzeň, Czech Republic
- Department of Mechanics, Faculty of Applied Sciences, University of West Bohemia, Plzeň, Czech Republic
| | - Jan Vimmr
- NTIS - New Technologies for the Information Society, Faculty of Applied Sciences, University of West Bohemia, Plzeň, Czech Republic
- Department of Mechanics, Faculty of Applied Sciences, University of West Bohemia, Plzeň, Czech Republic
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9
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Armstrong MK, Schultz MG, Hughes AD, Picone DS, Black JA, Dwyer N, Roberts-Thomson P, Sharman JE. Excess pressure as an analogue of blood flow velocity. J Hypertens 2021; 39:421-427. [PMID: 33031183 PMCID: PMC7116698 DOI: 10.1097/hjh.0000000000002662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Derivation of blood flow velocity from a blood pressure waveform is a novel technique, which could have potential clinical importance. Excess pressure, calculated from the blood pressure waveform via the reservoir-excess pressure model, is purported to be an analogue of blood flow velocity but this has never been examined in detail, which was the aim of this study. METHODS Intra-arterial blood pressure was measured sequentially at the brachial and radial arteries via fluid-filled catheter simultaneously with blood flow velocity waveforms recorded via Doppler ultrasound on the contralateral arm (n = 98, aged 61 ± 10 years, 72% men). Excess pressure was derived from intra-arterial blood pressure waveforms using pressure-only reservoir-excess pressure analysis. RESULTS Brachial and radial blood flow velocity waveform morphology were closely approximated by excess pressure derived from their respective sites of measurement (median cross-correlation coefficient r = 0.96 and r = 0.95 for brachial and radial comparisons, respectively). In frequency analyses, coherence between blood flow velocity and excess pressure was similar for brachial and radial artery comparisons (brachial and radial median coherence = 0.93 and 0.92, respectively). Brachial and radial blood flow velocity pulse heights were correlated with their respective excess pressure pulse heights (r = 0.53, P < 0.001 and r = 0.43, P < 0.001, respectively). CONCLUSION Excess pressure is an analogue of blood flow velocity, thus affording the opportunity to derive potentially important information related to arterial blood flow using only the blood pressure waveform.
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Affiliation(s)
| | - Martin G. Schultz
- Menzies Institute for Medical Research, University of Tasmania, Australia
| | - Alun D. Hughes
- Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Dean S. Picone
- Menzies Institute for Medical Research, University of Tasmania, Australia
| | | | - Nathan Dwyer
- Department of Cardiology, Royal Hobart Hospital, Australia
| | | | - James E. Sharman
- Menzies Institute for Medical Research, University of Tasmania, Australia
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10
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Smith R, Balmer J, Pretty CG, Mehta-Wilson T, Desaive T, Shaw GM, Chase JG. Incorporating pulse wave velocity into model-based pulse contour analysis method for estimation of cardiac stroke volume. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 195:105553. [PMID: 32497771 DOI: 10.1016/j.cmpb.2020.105553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/30/2020] [Accepted: 05/15/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVES Stroke volume (SV) and cardiac output (CO) are important metrics for hemodynamic management of critically ill patients. Clinically available devices to continuously monitor these metrics are invasive, and less invasive methods perform poorly during hemodynamic instability. Pulse wave velocity (PWV) could potentially improve estimation of SV and CO by providing information on changing vascular tone. This study investigates whether using PWV for parameter identification of a model-based pulse contour analysis method improves SV estimation accuracy. METHODS Three implementations of a 3-element windkessel pulse contour analysis model are compared: constant-Z, water hammer, and Bramwell-Hill methods. Each implementation identifies the characteristic impedance parameter (Z) differently. The first method identifies Z statically and does not use PWV, and the latter two methods use PWV to dynamically update Z. Accuracy of SV estimation is tested in an animal trial, where interventions induce severe hemodynamic changes in 5 pigs. Model-predicted SV is compared to SV measured using an aortic flow probe. RESULTS SV percentage error had median bias and [(IQR); (2.5th, 97.5th percentiles)] of -0.5% [(-6.1%, 4.7%); (-50.3%, +24.1%)] for the constant-Z method, 0.6% [(-4.9%, 6.2%); (-43.4%, +29.3%)] for the water hammer method, and 0.8% [(-6.5, 8.6); (-37.1%, +47.6%)] for the Bramwell-Hill method. CONCLUSION Incorporating PWV for dynamic Z parameter identification through either the Bramwell-Hill equation or the water hammer equation does not appreciably improve the 3-element windkessel pulse contour analysis model's prediction of SV during hemodynamic changes compared to the constant-Z method.
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Affiliation(s)
- Rachel Smith
- Department of Mechanical Engineering, University of Canterbury, New Zealand.
| | - Joel Balmer
- Department of Mechanical Engineering, University of Canterbury, New Zealand
| | | | | | - Thomas Desaive
- IGA Cardiovascular Science, University of Liége, Liége, Belgium
| | | | - J Geoffrey Chase
- Department of Mechanical Engineering, University of Canterbury, New Zealand
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Mynard JP, Kondiboyina A, Kowalski R, Cheung MMH, Smolich JJ. Measurement, Analysis and Interpretation of Pressure/Flow Waves in Blood Vessels. Front Physiol 2020; 11:1085. [PMID: 32973569 PMCID: PMC7481457 DOI: 10.3389/fphys.2020.01085] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/06/2020] [Indexed: 01/10/2023] Open
Abstract
The optimal performance of the cardiovascular system, as well as the break-down of this performance with disease, both involve complex biomechanical interactions between the heart, conduit vascular networks and microvascular beds. ‘Wave analysis’ refers to a group of techniques that provide valuable insight into these interactions by scrutinizing the shape of blood pressure and flow/velocity waveforms. The aim of this review paper is to provide a comprehensive introduction to wave analysis, with a focus on key concepts and practical application rather than mathematical derivations. We begin with an overview of invasive and non-invasive measurement techniques that can be used to obtain the signals required for wave analysis. We then review the most widely used wave analysis techniques—pulse wave analysis, wave separation and wave intensity analysis—and associated methods for estimating local wave speed or characteristic impedance that are required for decomposing waveforms into forward and backward wave components. This is followed by a discussion of the biomechanical phenomena that generate waves and the processes that modulate wave amplitude, both of which are critical for interpreting measured wave patterns. Finally, we provide a brief update on several emerging techniques/concepts in the wave analysis field, namely wave potential and the reservoir-excess pressure approach.
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Affiliation(s)
- Jonathan P Mynard
- Heart Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia.,Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, Australia.,Department of Cardiology, The Royal Children's Hospital, Parkville, VIC, Australia
| | - Avinash Kondiboyina
- Heart Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
| | - Remi Kowalski
- Heart Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia.,Department of Cardiology, The Royal Children's Hospital, Parkville, VIC, Australia
| | - Michael M H Cheung
- Heart Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia.,Department of Cardiology, The Royal Children's Hospital, Parkville, VIC, Australia
| | - Joseph J Smolich
- Heart Research, Murdoch Children's Research Institute, Melbourne, VIC, Australia.,Department of Paediatrics, The University of Melbourne, Melbourne, VIC, Australia
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Hametner B, Kastinger H, Wassertheurer S. Simulating re-reflections of arterial pressure waves at the aortic valve using difference equations. Proc Inst Mech Eng H 2020; 234:1243-1252. [PMID: 32686581 DOI: 10.1177/0954411920942704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Re-reflections of arterial pressure waves at the aortic valve and their influence on aortic wave shape are only poorly understood so far. Therefore, the aim of this work is to establish a model enabling the simulation of re-reflection and to test its properties. A mathematical difference equation model is used for the simulations. In this model, the aortic blood pressure is split into its forward and backward components which are calculated separately. The respective equations include reflection percentages representing reflections throughout the arterial system and a reflection coefficient at the aortic valve. While the distal reflections are fixed, different scenarios for the reflection coefficient at the valve are simulated. The results show that the model is capable to provide physiological pressure curves only if re-reflections are assumed to be present during the whole cardiac cycle. The sensitivity analysis on the reflection coefficient at the aortic valve shows various effects of re-reflections on the modelled blood pressure curve. Higher levels of the reflection coefficient lead to higher systolic and diastolic pressure values. The augmentation index is notably influenced by the systolic level of the reflection coefficient. This difference equation model gives an adequate possibility to simulate aortic pressure incorporating re-reflections at the site of the aortic valve. Since a strong dependence of the aortic pressure wave on the choice of the reflection coefficient have been found, this indicates that re-reflections should be incorporated into models of wave transmission. Furthermore, re-reflections may also be considered in methods of arterial pulse wave analysis.
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Affiliation(s)
- Bernhard Hametner
- Center for Health & Bioresources, AIT Austrian Institute of Technology, Vienna, Austria
| | - Hannah Kastinger
- Center for Health & Bioresources, AIT Austrian Institute of Technology, Vienna, Austria.,Institute for Analysis and Scientific Computing, Vienna University of Technology, Vienna, Austria
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Kondiboyina A, Smolich JJ, Cheung MMH, Westerhof BE, Mynard JP. Conduit arterial wave reflection promotes pressure transmission but impedes hydraulic energy transmission to the microvasculature. Am J Physiol Heart Circ Physiol 2020; 319:H66-H75. [DOI: 10.1152/ajpheart.00733.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
With aging, a reduction in the stiffness gradient between elastic and muscular arteries is thought to reduce wave reflection in conduit arteries, leading to increased pulsatile pressure transmission into the microvasculature. This assumes that wave reflection limits pressure transmission in arteries. However, using a computational model, we showed that wave reflection promotes pulsatile pressure transmission, although it does limit hydraulic energy transmission. Increased microvascular pulse pressure with aging is instead related to decreasing arterial compliance.
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Affiliation(s)
- Avinash Kondiboyina
- Heart Research, Murdoch Children’s Research Institute, Parkville, Victoria, Australia
- Department of Pediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Joseph J. Smolich
- Heart Research, Murdoch Children’s Research Institute, Parkville, Victoria, Australia
- Department of Pediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Michael M. H. Cheung
- Heart Research, Murdoch Children’s Research Institute, Parkville, Victoria, Australia
- Department of Pediatrics, University of Melbourne, Parkville, Victoria, Australia
- Department of Cardiology, Royal Children’s Hospital, Parkville, Victoria, Australia
| | - Berend E. Westerhof
- Cardiovascular and Respiratory Physiology, Faculty of Science and Technology, Technical Medical Centre, University of Twente, Enschede, The Netherlands
- Department of Pulmonary Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Jonathan P. Mynard
- Heart Research, Murdoch Children’s Research Institute, Parkville, Victoria, Australia
- Department of Pediatrics, University of Melbourne, Parkville, Victoria, Australia
- Department of Cardiology, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Biomedical Engineering, University of Melbourne, Parkville, Victoria, Australia
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Salvi L, Alfonsi J, Grillo A, Pini A, Soranna D, Zambon A, Pacini D, Di Bartolomeo R, Salvi P, Parati G. Postoperative and mid-term hemodynamic changes after replacement of the ascending aorta. J Thorac Cardiovasc Surg 2020; 163:1283-1292. [PMID: 32624310 DOI: 10.1016/j.jtcvs.2020.05.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 04/08/2020] [Accepted: 05/08/2020] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To evaluate aortic distensibility and pulse waveform patterns associated with the ascending aortic aneurysm, and to analyze the postoperative and mid-term hemodynamic changes induced by prosthetic replacement of the ascending aorta. METHODS Central blood pressure waves were recorded at the carotid artery level by means of a validated transcutaneous arterial tonometer in 30 patients undergoing prosthetic replacement of ascending aortic aneurysm and in 30 control patients. Measurements were obtained the day before surgery and 5 to 7 days and 16 to 20 months after surgery. RESULTS The ascending aortic aneurysm was associated with a less steep slope of early systolic phase of the pressure curve (pulsus tardus) compared with a control group (0.54 ± 0.18 mm Hg/ms vs 0.69 ± 0.26 mm Hg/ms; P = .011). Replacing the ascending aorta with a noncompliant vascular prosthesis steepened the pulse pressure slope during the early systolic phase in the postoperative period (0.77 ± .29 mm Hg/ms), providing values comparable with those of the control group in the mid-term (0.67 ± .20 mm Hg/ms). No change in aortic stiffness was found either postoperatively or in the mid-term after ascending aorta surgical replacement (carotid-femoral pulse wave velocity: preoperative, 9.0 ± 2.6 m/s; postoperative, 9.0 ± 2.9 m/s; mid-term postoperative, 9.3 ± 2.8 m/s). CONCLUSIONS This study does not confirm the assumption that substitution of the viscoelastic ascending aorta with a rigid prosthesis can cause serious hemodynamic alterations downstream, because we did not observe a worsening of global aortic distensibility after insertion of a rigid prosthetic aorta. The ascending aortic aneurysm is associated with a pulsus tardus.
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Affiliation(s)
- Lucia Salvi
- Foundation IRCCS Polyclinic San Matteo, University of Pavia, Pavia, Italy
| | - Jacopo Alfonsi
- Department of Cardiovascular Surgery, S Orsola Hospital, University of Bologna, Bologna, Italy
| | - Andrea Grillo
- Istituto Auxologico Italiano, IRCCS, Cardiology Unit, Milan, Italy; Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
| | - Alessandro Pini
- Vascular Cardiogenetic Unit, IRCCS Policlinico San Donato, San Donato Milanese, Italy
| | - Davide Soranna
- Istituto Auxologico Italiano, IRCCS, Cardiology Unit, Milan, Italy
| | - Antonella Zambon
- Istituto Auxologico Italiano, IRCCS, Cardiology Unit, Milan, Italy; Department of Statistics and Quantitative Methods, University of Milano-Bicocca, Milan, Italy
| | - Davide Pacini
- Department of Cardiovascular Surgery, S Orsola Hospital, University of Bologna, Bologna, Italy
| | - Roberto Di Bartolomeo
- Department of Cardiovascular Surgery, S Orsola Hospital, University of Bologna, Bologna, Italy
| | - Paolo Salvi
- Istituto Auxologico Italiano, IRCCS, Cardiology Unit, Milan, Italy.
| | - Gianfranco Parati
- Istituto Auxologico Italiano, IRCCS, Cardiology Unit, Milan, Italy; Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
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15
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Hughes AD, Parker KH. The modified arterial reservoir: An update with consideration of asymptotic pressure ( P∞) and zero-flow pressure ( Pzf). Proc Inst Mech Eng H 2020; 234:1288-1299. [PMID: 32367773 PMCID: PMC7705641 DOI: 10.1177/0954411920917557] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This article describes the modified arterial reservoir in detail. The modified arterial reservoir makes explicit the wave nature of both reservoir (Pres) and excess pressure (Pxs). The mathematical derivation and methods for estimating Pres in the absence of flow velocity data are described. There is also discussion of zero-flow pressure (Pzf), the pressure at which flow through the circulation ceases; its relationship to asymptotic pressure (P∞) estimated by the reservoir model; and the physiological interpretation of Pzf . A systematic review and meta-analysis provides evidence that Pzf differs from mean circulatory filling pressure.
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Affiliation(s)
- Alun D Hughes
- MRC Unit for Lifelong Health and Ageing at UCL, Department of Population Science and Experimental Medicine, Institute of Cardiovascular Science, University College London, London, UK
| | - Kim H Parker
- Department of Bioengineering, Imperial College London, London, UK
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Balmer J, Pretty CG, Davidson S, Mehta-Wilson T, Desaive T, Smith R, Shaw GM, Chase JG. Clinically applicable model-based method, for physiologically accurate flow waveform and stroke volume estimation. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 185:105125. [PMID: 31698169 DOI: 10.1016/j.cmpb.2019.105125] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 08/10/2019] [Accepted: 10/07/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND OBJECTIVES Cardiovascular dysfunction can be more effectively monitored and treated, with accurate, continuous, stroke volume (SV) and/or cardiac output (CO) measurements. Since direct measurements of SV/CO are highly invasive, clinical measures are often discrete, or if continuous, can require recalibration with a discrete SV measurement after hemodynamic instability. This study presents a clinically applicable, non-additionally invasive, physiological model-based, SV and CO measurement method, which does not require recalibration during or after hemodynamic instability. METHODS AND RESULTS The model's ability to predict flow profiles and SV is assessed in an animal trial, using endotoxin to induce sepsis in 5 pigs. Mean percentage error between beat-to-beat SV measured from an aortic flow probe and estimated by the model was -2%, while 90% of estimations fell within -24.2% and +27.9% error. Error between estimated and measured changes in mean SV following interventions was less than 30% for 4 out of the 5 pigs. Correlations between model estimated and probe measured flow, for each pig and hemodynamic interventions, was r2 = 0.58 - 0.96, with 21 of the 25 pig intervention stages having r2 > 0.80. CONCLUSION The results demonstrate the model accurately estimates and tracks changes in flow profiles and resulting SV, without requiring model recalibration.
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Affiliation(s)
- Joel Balmer
- Department of Mechanical Engineering, University of Canterbury, New Zealand.
| | | | - Shaun Davidson
- Department of Mechanical Engineering, University of Canterbury, New Zealand
| | | | - Thomas Desaive
- GIGA Cardiovascular Science, University of Liège, Liège, Belgium
| | - Rachel Smith
- Department of Mechanical Engineering, University of Canterbury, New Zealand
| | | | - J Geoffrey Chase
- Department of Mechanical Engineering, University of Canterbury, New Zealand
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Westerhof BE, Westerhof N. Uniform tube models with single reflection site do not explain aortic wave travel and pressure wave shape. Physiol Meas 2018; 39:124006. [DOI: 10.1088/1361-6579/aaf3dd] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Hydren JR, Richardson RS, Symons JD, Mynard JP, Smolich JJ, Ramos JS, Dias KA, Dalleck LC, Drummond C, Westerhof B, Westerhof N, Zuo L, Zhou T. Commentaries on Viewpoint: Origin of the forward-going "backward" wave. J Appl Physiol (1985) 2017; 123:1408-1410. [PMID: 29167201 DOI: 10.1152/japplphysiol.00758.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 11/22/2022] Open
Affiliation(s)
| | | | | | | | | | | | - Katrin A Dias
- Institute for Exercise and Environmental Medicine.,University of Texas Southwestern Medical Center
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Abstract
PURPOSE OF REVIEW Arterial pulse waveform analysis has a long tradition but has not pervaded medical routine yet. This review aims to answer the question whether the methodology is ready for prime time use. The current methodological consensus is assessed, existing technologies for waveform measurement and pulse wave analysis are discussed, and further needs for a widespread use are proposed. RECENT FINDINGS A consensus document on the understanding and analysis of the pulse waveform was published recently. Although still some discrepancies remain, the analysis using both pressure and flow waves is favoured. However, devices which enable pulse wave measurement are limited, and the comparability between devices is not sufficiently given. Pulse waveform analysis has the potential for prime time. It is currently on a way towards broader use, but still needs to overcome challenges before settling its role in medical routine.
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