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Pal R, Rudas A, Kim S, Chiang JN, Barney A, Cannesson M. An algorithm to detect dicrotic notch in arterial blood pressure and photoplethysmography waveforms using the iterative envelope mean method. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 254:108283. [PMID: 38901273 PMCID: PMC11323035 DOI: 10.1016/j.cmpb.2024.108283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Revised: 05/28/2024] [Accepted: 06/07/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND AND OBJECTIVE Detection of the dicrotic notch (DN) within a cardiac cycle is essential for assessment of cardiac output, calculation of pulse wave velocity, estimation of left ventricular ejection time, and supporting feature-based machine learning models for noninvasive blood pressure estimation, and hypotension, or hypertension prediction. In this study, we present a new algorithm based on the iterative envelope mean (IEM) method to detect automatically the DN in arterial blood pressure (ABP) and photoplethysmography (PPG) waveforms. METHODS The algorithm was evaluated on both ABP and PPG waveforms from a large perioperative dataset (MLORD dataset) comprising 17,327 patients. The analysis involved a total of 1,171,288 cardiac cycles for ABP waveforms and 3,424,975 cardiac cycles for PPG waveforms. To evaluate the algorithm's performance, the systolic phase duration (SPD) was employed, which represents the duration from the onset of the systolic phase to the DN in the cardiac cycle. Correlation plots and regression analysis were used to compare the algorithm against marked DN detection, while box plots and Bland-Altman plots were used to compare its performance with both marked DN detection and an established DN detection technique (second derivative). The marking of the DN temporal location was carried out by an experienced researcher using the help of the 'find_peaks' function from the scipy Python package, serving as a reference for the evaluation. The marking was visually validated by both an engineer and an anesthesiologist. The robustness of the algorithm was evaluated as the DN was made less visually distinct across signal-to-noise ratios (SNRs) ranging from -30 dB to -5 dB in both ABP and PPG waveforms. RESULTS The correlation between SPD estimated by the algorithm and that marked by the researcher is strong for both ABP (R2(87,343) =0.99, p<.001) and PPG (R2(86,764) =0.98, p<.001) waveforms. The algorithm had a lower mean error of DN detection (s): 0.0047 (0.0029) for ABP waveforms and 0.0046 (0.0029) for PPG waveforms, compared to 0.0693 (0.0770) for ABP and 0.0968 (0.0909) for PPG waveforms for the established 2nd derivative method. The algorithm has high rate of detectability of DN detection for SNR of >= -9 dB for ABP waveforms and >= -12 dB for PPG waveforms indicating robust performance in detecting the DN when it is less visibly distinct. CONCLUSION Our proposed IEM- based algorithm can detect DN in both ABP and PPG waveforms with low computational cost, even in cases where it is not distinctly defined within a cardiac cycle of the waveform ('DN-less signals'). The algorithm can potentially serve as a valuable, fast, and reliable tool for extracting features from ABP and PPG waveforms. It can be especially beneficial in medical applications where DN-based features, such as SPD, diastolic phase duration, and DN amplitude, play a significant role.
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Affiliation(s)
- Ravi Pal
- Department of Anesthesiology & Perioperative Medicine, University of California, Los Angeles, CA, USA
| | - Akos Rudas
- Department of Computational Medicine, University of California, Los Angeles, CA, USA
| | - Sungsoo Kim
- Department of Anesthesiology & Perioperative Medicine, University of California, Los Angeles, CA, USA
| | - Jeffrey N Chiang
- Department of Computational Medicine, University of California, Los Angeles, CA, USA
| | - Anna Barney
- Institute of Sound and Vibration Research (ISVR), University of Southampton, Southampton, United Kingdom
| | - Maxime Cannesson
- Department of Anesthesiology & Perioperative Medicine, University of California, Los Angeles, CA, USA.
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Tian G, Deng W, Yang T, Zhang J, Xu T, Xiong D, Lan B, Wang S, Sun Y, Ao Y, Huang L, Liu Y, Li X, Jin L, Yang W. Hierarchical Piezoelectric Composites for Noninvasive Continuous Cardiovascular Monitoring. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2313612. [PMID: 38574762 DOI: 10.1002/adma.202313612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/25/2024] [Indexed: 04/06/2024]
Abstract
Continuous monitoring of blood pressure (BP) and multiparametric analysis of cardiac functions are crucial for the early diagnosis and therapy of cardiovascular diseases. However, existing monitoring approaches often suffer from bulky and intrusive apparatus, cumbersome testing procedures, and challenging data processing, hampering their applications in continuous monitoring. Here, a heterogeneously hierarchical piezoelectric composite is introduced for wearable continuous BP and cardiac function monitoring, overcoming the rigidity of ceramic and the insensitivity of polymer. By optimizing the hierarchical structure and components of the composite, the developed piezoelectric sensor delivers impressive performances, ensuring continuous and accurate monitoring of BP at Grade A level. Furthermore, the hemodynamic parameters are extracted from the detected signals, such as local pulse wave velocity, cardiac output, and stroke volume, all of which are in alignment with clinical results. Finally, the all-day tracking of cardiac function parameters validates the reliability and stability of the developed sensor, highlighting its potential for personalized healthcare systems, particularly in early diagnosis and timely intervention of cardiovascular disease.
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Affiliation(s)
- Guo Tian
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Weili Deng
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Tao Yang
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Jieling Zhang
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Tianpei Xu
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Da Xiong
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Boling Lan
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Shenglong Wang
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Yue Sun
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Yong Ao
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Longchao Huang
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Yang Liu
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Xuelan Li
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Long Jin
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
| | - Weiqing Yang
- Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, P. R. China
- Research Institute of Frontier Science, Southwest Jiaotong University, Chengdu, 610031, P. R. China
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Pal R, Rudas A, Kim S, Chiang JN, Braney A, Cannesson M. An algorithm to detect dicrotic notch in arterial blood pressure and photoplethysmography waveforms using the iterative envelope mean method. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.03.05.24303735. [PMID: 38496617 PMCID: PMC10942507 DOI: 10.1101/2024.03.05.24303735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Background and Objective Detection of the dicrotic notch (DN) within a cardiac cycle is essential for assessment of cardiac output, calculation of pulse wave velocity, estimation of left ventricular ejection time, and supporting feature-based machine learning models for noninvasive blood pressure estimation, and hypotension, or hypertension prediction. In this study, we present a new algorithm based on the iterative envelope mean (IEM) method to detect automatically the DN in arterial blood pressure (ABP) and photoplethysmography (PPG) waveforms. Methods The algorithm was evaluated on both ABP and PPG waveforms from a large perioperative dataset (MLORD dataset) comprising 17,327 patients. The analysis involved a total of 1,171,288 cardiac cycles for ABP waveforms and 3,424,975 cardiac cycles for PPG waveforms. To evaluate the algorithm's performance, the systolic phase duration (SPD) was employed, which represents the duration from the onset of the systolic phase to the DN in the cardiac cycle. Correlation plots and regression analysis were used to compare the algorithm with an established DN detection technique (second derivative). The marking of the DN temporal location was carried out by an experienced researcher using the help of the 'find_peaks' function from the scipy PYTHON package, serving as a reference for the evaluation. The marking was visually validated by both an engineer and an anesthesiologist. The robustness of the algorithm was evaluated as the DN was made less visually distinct across signal-to-noise ratios (SNRs) ranging from -30 dB to -5 dB in both ABP and PPG waveforms. Results The correlation between SPD estimated by the algorithm and that marked by the researcher is strong for both ABP (R2(87343) =.99, p<.001) and PPG (R2(86764) =.98, p<.001) waveforms. The algorithm had a lower mean error of dicrotic notch detection (s): 0.0047 (0.0029) for ABP waveforms and 0.0046 (0.0029) for PPG waveforms, compared to 0.0693 (0.0770) for ABP and 0.0968 (0.0909) for PPG waveforms for the established 2nd derivative method. The algorithm has high accuracy of DN detection for SNR of >= -9 dB for ABP waveforms and >= -12 dB for PPG waveforms indicating robust performance in detecting the DN when it is less visibly distinct. Conclusion Our proposed IEM- based algorithm can detect DN in both ABP and PPG waveforms with low computational cost, even in cases where it is not distinctly defined within a cardiac cycle of the waveform ('DN-less signals'). The algorithm can potentially serve as a valuable, fast, and reliable tool for extracting features from ABP and PPG waveforms. It can be especially beneficial in medical applications where DN-based features, such as SPD, diastolic phase duration, and DN amplitude, play a significant role.
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Affiliation(s)
- Ravi Pal
- Department of Anesthesiology & Perioperative Medicine, University of California, Los Angeles, CA, USA
| | - Akos Rudas
- Department of Computational Medicine, University of California, Los Angeles, CA, USA
| | - Sungsoo Kim
- Department of Anesthesiology & Perioperative Medicine, University of California, Los Angeles, CA, USA
| | - Jeffrey N Chiang
- Department of Computational Medicine, University of California, Los Angeles, CA, USA
| | - Anna Braney
- Institute of Sound and Vibration Research (ISVR), University of Southampton, Southampton, United Kingdom
| | - Maxime Cannesson
- Department of Anesthesiology & Perioperative Medicine, University of California, Los Angeles, CA, USA
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MacRaild M, Sarrami-Foroushani A, Lassila T, Frangi AF. Accelerated simulation methodologies for computational vascular flow modelling. J R Soc Interface 2024; 21:20230565. [PMID: 38350616 PMCID: PMC10864099 DOI: 10.1098/rsif.2023.0565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 01/12/2024] [Indexed: 02/15/2024] Open
Abstract
Vascular flow modelling can improve our understanding of vascular pathologies and aid in developing safe and effective medical devices. Vascular flow models typically involve solving the nonlinear Navier-Stokes equations in complex anatomies and using physiological boundary conditions, often presenting a multi-physics and multi-scale computational problem to be solved. This leads to highly complex and expensive models that require excessive computational time. This review explores accelerated simulation methodologies, specifically focusing on computational vascular flow modelling. We review reduced order modelling (ROM) techniques like zero-/one-dimensional and modal decomposition-based ROMs and machine learning (ML) methods including ML-augmented ROMs, ML-based ROMs and physics-informed ML models. We discuss the applicability of each method to vascular flow acceleration and the effectiveness of the method in addressing domain-specific challenges. When available, we provide statistics on accuracy and speed-up factors for various applications related to vascular flow simulation acceleration. Our findings indicate that each type of model has strengths and limitations depending on the context. To accelerate real-world vascular flow problems, we propose future research on developing multi-scale acceleration methods capable of handling the significant geometric variability inherent to such problems.
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Affiliation(s)
- Michael MacRaild
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), University of Leeds, Leeds, UK
- EPSRC Centre for Doctoral Training in Fluid Dynamics, University of Leeds, Leeds, UK
| | - Ali Sarrami-Foroushani
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), University of Leeds, Leeds, UK
- School of Health Science, University of Manchester, Manchester, UK
| | - Toni Lassila
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), University of Leeds, Leeds, UK
- School of Computing, University of Leeds, Leeds, UK
| | - Alejandro F. Frangi
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), University of Leeds, Leeds, UK
- School of Computer Science, University of Manchester, Manchester, UK
- School of Health Science, University of Manchester, Manchester, UK
- Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
- Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium
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Heitner TJ, Livneh A, Landesberg A. Novel Peripheral Perfusion Dynamics Indices for Detecting and Grading Arterial Stenosis. Cardiovasc Eng Technol 2023; 14:774-785. [PMID: 37985616 DOI: 10.1007/s13239-023-00686-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/11/2023] [Indexed: 11/22/2023]
Abstract
PURPOSE Peripheral artery disease causes severe morbidity, especially in diabetics and the elderly. There is a need for accurate noninvasive detection of peripheral arterial stenosis. The study has tested the hypothesis that arterial stenosis and the associated adaptation of the downstream circulation yield characteristic changes in the leg perfusion dynamics that enable early diagnosis, utilizing impedance plethysmography. METHODS The arterial perfusion dynamic was derived from impedance plethysmography (IPG). Two degrees of arterial stenosis were emulated by inflating a blood-pressure cuff around the thigh to 45 and 90 mmHg, in healthy volunteers (n = 30). IPG signals were acquired continuously throughout the experiment. Ankle and brachial blood pressures were measured at the beginning of each experiment and at the end of each emulated stenosis phase. RESULTS Thigh compressions did not affect the pulse-transit time, but prolonged the time to the peak perfusion wave. Segmentation of the perfusion upstroke into two phases, at the time point of maximum acceleration (MAT), revealed that arterial compression prolonged only the initial slow phase duration (SPd). The MAT and SPd were proportional to the emulated stenosis severity and detected the arterial stenosis with high sensitivity (> 93%) and specificity (100%). The SPd increased from 46.4 ± 21.2 ms at baseline to 75.4 ± 38.5 ms and 145 ± 39 ms under 45 mmHg and 90 mmHg compressions (p < 0.001), without affecting the pulse-transit time. CONCLUSIONS The novel method and indices can identify and grade the emulated arterial stenosis with high accuracy and may assist in differentiating between focal arterial stenosis and widespread arterial hardening.
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Affiliation(s)
- Tomer Joshua Heitner
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Amit Livneh
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Amir Landesberg
- Faculty of Biomedical Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel.
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Abushouk A, Kansara T, Abdelfattah O, Badwan O, Hariri E, Chaudhury P, Kapadia SR. The Dicrotic Notch: Mechanisms, Characteristics, and Clinical Correlations. Curr Cardiol Rep 2023; 25:807-816. [PMID: 37493873 DOI: 10.1007/s11886-023-01901-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/05/2023] [Indexed: 07/27/2023]
Abstract
PURPOSE OF REVIEW The dicrotic notch (DN) has long been considered a marker of arterial stiffness and compliance. Herein, we explored the recent developments in vascular medicine research in an attempt to assess the DN utility in clinical cardiovascular medicine. RECENT FINDINGS Since its discovery, several studies have attempted to measure the changes in different parameters of the DN in physiological and pathological states. Despite the significance of their findings, the clinical role of the DN remained limited. This may have been related to the difficulty of measuring the DN via indwelling arterial catheters in the past. However, over the past two decades, several non-invasive methods have been developed, which may re-ignite interest in DN research. The DN may have broader applications in clinical cardiovascular medicine. Further research is needed to establish the accuracy of DN non-invasive measurement methods and compare its prognostic value to other circulatory parameters.
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Affiliation(s)
- Abdelrahman Abushouk
- Department of Cardiovascular Medicine, Heart, Vascular, and Thoracic Institute, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, USA
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Tikal Kansara
- Department of Hospital Medicine, Union Hospital, Cleveland Clinic Foundation, Dover, OH, USA
| | - Omar Abdelfattah
- Division of Cardiovascular Medicine, University of Texas Medical Branch, Galveston, TX, USA
| | - Osamah Badwan
- Department of Internal Medicine, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Essa Hariri
- Department of Internal Medicine, Cleveland Clinic Foundation, Cleveland, OH, USA
- Division of Cardiovascular Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Pulkit Chaudhury
- Department of Cardiovascular Medicine, Heart, Vascular, and Thoracic Institute, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, USA
| | - Samir R Kapadia
- Department of Cardiovascular Medicine, Heart, Vascular, and Thoracic Institute, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, USA.
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Gimblet CJ, Armstrong MK, Nuckols VR, DuBose LE, Holwerda SW, Luehrs RE, Lane AD, Voss MW, Pierce GL. Sex-specific associations of reservoir-excess pressure parameters with age and subclinical vascular remodeling. J Hypertens 2023; 41:624-631. [PMID: 36723472 PMCID: PMC10980292 DOI: 10.1097/hjh.0000000000003378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Central artery reservoir pressure and excess pressure (XSP) are associated with cardiovascular disease (CVD) events and mortality. However, sex differences in the trajectory of central reservoir pressure and XSP with advancing age and their relations with vascular markers of subclinical CVD risk are incompletely understood. Therefore, we tested the hypothesis that central reservoir pressure and XSP would be positively associated with advancing age and vascular markers of subclinical CVD risk in men and women. METHOD Healthy adults ( n = 398; aged 18-80 years, 60% female individuals) had central (carotid) artery pressure waveforms acquired by applanation tonometry. Reservoir pressure and XSP peaks and integrals were derived retrospectively from carotid pressure waveforms using custom written software. Carotid artery intimal-medial thickness (IMT) was measured by ultrasonography, and aortic stiffness was determined from carotid-femoral pulse wave velocity (cfPWV). RESULTS Reservoir pressure peak, reservoir pressure integral and XSP integral were higher with age in both men and women ( P < 0.05), whereas XSP peak was lower with age in men ( P < 0.05). In women, both reservoir pressure peak ( β = 0.231, P < 0.01) and reservoir pressure integral ( β = 0.254, P < 0.01) were associated with carotid artery IMT, and reservoir pressure peak was associated with cfPWV ( β = 0.120, P = 0.02) after adjusting for CVD risk factors. CONCLUSION Central artery reservoir pressure and XSP were higher with advancing age in men and women, and reservoir pressure peak was associated with both carotid artery wall thickness and aortic stiffness in women but not men. Central reservoir pressure peak may provide some insight into sex differences in vascular remodeling and subclinical CVD risk with advancing age in healthy adults.
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Affiliation(s)
- Colin J. Gimblet
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Matthew K. Armstrong
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Virginia R. Nuckols
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
| | - Lyndsey E. DuBose
- Department of Medicine, Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Seth W. Holwerda
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Rachel E. Luehrs
- Department of Kinesiology, North Central College, Naperville, IL, USA
| | - Abbi D. Lane
- Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, SC USA
| | - Michelle W. Voss
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA USA
| | - Gary L. Pierce
- Department of Health and Human Physiology, University of Iowa, Iowa City, IA, USA
- Department of Internal Medicine, University of Iowa, Iowa City, IA, USA
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Hametner B, Weber T, Wassertheurer S. Heart Failure: Insights From the Arterial Waves. J Am Heart Assoc 2023; 12:e029116. [PMID: 36892064 PMCID: PMC10111562 DOI: 10.1161/jaha.123.029116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Affiliation(s)
- Bernhard Hametner
- Center for Health & Bioresources AIT Austrian Institute of Technology Vienna Austria
| | - Thomas Weber
- Cardiology Department, Klinikum Wels-Grieskirchen Wels Austria
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Deng Z, Guo L, Chen X, Wu W. Smart Wearable Systems for Health Monitoring. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23052479. [PMID: 36904682 PMCID: PMC10007426 DOI: 10.3390/s23052479] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/19/2023] [Accepted: 02/21/2023] [Indexed: 06/12/2023]
Abstract
Smart wearable systems for health monitoring are highly desired in personal wisdom medicine and telemedicine. These systems make the detecting, monitoring, and recording of biosignals portable, long-term, and comfortable. The development and optimization of wearable health-monitoring systems have focused on advanced materials and system integration, and the number of high-performance wearable systems has been gradually increasing in recent years. However, there are still many challenges in these fields, such as balancing the trade-off between flexibility/stretchability, sensing performance, and the robustness of systems. For this reason, more evolution is required to promote the development of wearable health-monitoring systems. In this regard, this review summarizes some representative achievements and recent progress of wearable systems for health monitoring. Meanwhile, a strategy overview is presented about selecting materials, integrating systems, and monitoring biosignals. The next generation of wearable systems for accurate, portable, continuous, and long-term health monitoring will offer more opportunities for disease diagnosis and treatment.
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Affiliation(s)
- Zhiyong Deng
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
- Nuclear Power Institute of China, Huayang, Shuangliu District, Chengdu 610213, China
| | - Lihao Guo
- School of Advanced Materials and Nanotechnology, Interdisciplinary Research Center of Smart Sensors, Xidian University, Xi’an 710126, China
| | - Ximeng Chen
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - Weiwei Wu
- School of Advanced Materials and Nanotechnology, Interdisciplinary Research Center of Smart Sensors, Xidian University, Xi’an 710126, China
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Jin J, Geng X, Zhang Y, Zhang H, Ye T. Pulse Wave Analysis Method of Cardiovascular Parameters Extraction for Health Monitoring. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:2597. [PMID: 36767962 PMCID: PMC9915975 DOI: 10.3390/ijerph20032597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
OBJECTIVE A pulse waveform is regarded as an information carrier of the cardiovascular system, which contains multiple interactive cardiovascular parameters reflecting physio-pathological states of bodies. Hence, multiple parameter analysis is increasingly meaningful to date but still cannot be easily achieved one by one due to the complex mapping between waveforms. This paper describes a new analysis method based on waveform recognition aimed for extracting multiple cardiovascular parameters to monitor public health. The objective of this new method is to deduce multiple cardiovascular parameters for a target pulse waveform based on waveform recognition to a most similar reference waveform in a given database or pattern library. METHODS The first part of the methodology includes building the sub-pattern libraries and training classifier. This provides a trained classifier and the sub-pattern library with reference pulse waveforms and known parameters. The second part is waveform analysis. The target waveform will be classified and output a state category being used to select the corresponding sub-pattern library with the same state. This will reduce subsequent recognition scope and computation costs. The mainstay of this new analysis method is improved dynamic time warping (DTW). This improved DTW and K-Nearest Neighbors (KNN) were applied to recognize the most similar waveform in the pattern library. Hence, cardiovascular parameters can be assigned accordingly from the most similar waveform in the pattern library. RESULTS Four hundred and thirty eight (438) randomly selected pulse waveforms were tested to verify the effectiveness of this method. The results show that the classification accuracy is 96.35%. Using statistical analysis to compare the target sample waveforms and the recognized reference ones from within the pattern library, most correlation coefficients are beyond 0.99. Each set of cardiovascular parameters was assessed using the Bland-Altman plot. The extracted cardiovascular parameters are in strong agreement with the original verifying the effectiveness of this new approach. CONCLUSION This new method using waveform recognition shows promising results that can directly extract multiple cardiovascular parameters from waveforms with high accuracy. This new approach is efficient and effective and is very promising for future continuous monitoring of cardiovascular health.
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Affiliation(s)
- Ji Jin
- The Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xingguang Geng
- The Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
| | - Yitao Zhang
- The Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
| | - Haiying Zhang
- The Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianchun Ye
- The Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Picone DS, Kodithuwakku V, Mayer CC, Chapman N, Rehman S, Climie RE. Sex differences in pressure and flow waveform physiology across the life course. J Hypertens 2022; 40:2373-2384. [PMID: 36093877 DOI: 10.1097/hjh.0000000000003283] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Cardiovascular disease (CVD) has long been deemed a disease of old men. However, in 2019 CVD accounted for 35% of all deaths in women and, therefore, remains the leading cause of death in both men and women. There is increasing evidence to show that risk factors, pathophysiology and health outcomes related to CVD differ in women compared with men, yet CVD in women remains understudied, underdiagnosed and undertreated. Differences exist between the sexes in relation to the structure of the heart and vasculature, which translate into differences in blood pressure and flow waveform physiology. These physiological differences between women and men may represent an important explanatory factor contributing to the sex disparity in CVD presentation and outcomes but remain understudied. In this review we aim to describe sex differences in arterial pressure and flow waveform physiology and explore how they may contribute to differences in CVD in women compared to men. Given that unfavourable alterations in the cardiovascular structure and function can start as early as in utero, we report sex differences in waveform physiology across the entire life course.
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Affiliation(s)
- Dean S Picone
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | | | - Christopher C Mayer
- Medical Signal Analysis, Center for Health & Bioresources, AIT Austrian Institute of Technology, Vienna, Austria
| | - Niamh Chapman
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Sabah Rehman
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Rachel E Climie
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
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12
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Excess pressure but not pulse wave velocity is associated with cognitive function impairment: a community-based study. J Hypertens 2022; 40:1776-1785. [PMID: 35943104 DOI: 10.1097/hjh.0000000000003217] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Carotid-femoral pulse wave velocity (cf-PWV), an index of mainly distal aortic stiffness, has been inconsistently associated with cognitive function. Excess pressure, derived from the arterial reservoir-excess pressure analysis, may integrate the pulsatile load of the proximal aorta. The present study examined whether increased excess pressure is associated with cognitive function impairment in community adults. METHODS A total of 992 community participants (69.5% females; mean age: 67.3 years; education 13.6 years) without cerebrovascular disease or dementia received the Montreal Cognitive Assessment (MoCA) to evaluate global cognition. Arterial reservoir and excess pressure, arterial stiffness, and wave reflections were assessed, using carotid tonometry and aortic Doppler flowmetry. RESULTS Excess pressure integral (XSPI), percentage XSPI, cf-PWV, characteristic impedance (Zc), and forward and backward pressure amplitude (Pf, Pb, respectively) were significantly higher in 197 participants (19.9%) with a low MoCA score (<26 or <25, depending on level of education). In multivariable analyses, XSPI (standardized odds ratio, 95% confidence interval, 1.30, 1.06-1.59), and percentage XSPI (1.27, 1.06-1.52) but not cf-PWV (1.04, 0.85-1.26) were significantly associated with a low MoCA. Further analysis revealed that Pf and Zc were the major determinants of XSPI (partial R2: Pf = 0.656, Zc = 0.467) and percentage XSPI (Pf = 0.459, Zc = 0.371). In contrast, age, instead of Pf and Zc, was the major determinant of cf-PWV (partial R2: age = 0.187). CONCLUSIONS Excess pressure (XSPI/percentage XSPI), mainly determined by the pulsatile hemodynamics of the proximal aorta, was significantly associated with cognitive function impairment in middle-aged and elderly community adults.
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13
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Guest B, Arroyo L, Runciman J. A structural approach to 3D-printing arterial phantoms with physiologically comparable mechanical characteristics: Preliminary observations. Proc Inst Mech Eng H 2022; 236:1388-1402. [PMID: 35913071 PMCID: PMC9449448 DOI: 10.1177/09544119221114207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pulse wave behavior is important in cardiovascular pathophysiology and arterial
phantoms are valuable for studying arterial function. The ability of phantoms to
replicate complex arterial elasticity and anatomy is limited by available
materials and techniques. The feasibility of improving phantom performance using
functional structure designs producible with practical 3D printing technologies
was investigated. A novel corrugated wall approach to separate phantom function
from material properties was investigated with a series of designs printed from
polyester-polyurethane using a low-cost open-source fused filament fabrication
3D printer. Nonpulsatile pressure-diameter data was collected, and a mock
circulatory system was used to observe phantom pulse wave behavior and obtain
pulse wave velocities. The measured range of nonpulsatile Peterson elastic
strain modulus was 5.6–19 to 12.4–33.0 kPa over pressures of 5–35 mmHg for the
most to least compliant designs respectively. Pulse wave velocities of
1.5–5 m s−1 over mean pressures of 7–55 mmHg were observed,
comparing favorably to reported in vivo pulmonary artery measurements of
1–4 m s−1 across mammals. Phantoms stiffened with increasing
pressure in a manner consistent with arteries, and phantom wall elasticity
appeared to vary between designs. Using a functional structure approach,
practical low-cost 3D-printed production of simple arterial phantoms with
mechanical properties that closely match the pulmonary artery is possible.
Further functional structure design development to expand the pressure range and
physiologic utility of dir"ectly 3D-printed phantoms appears warranted.
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Affiliation(s)
- Bruce Guest
- School of Engineering, University of Guelph, Guelph, ON, Canada
- Ontario Veterinary College Health Sciences Centre, University of Guelph, Guelph, ON, Canada
| | - Luis Arroyo
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - John Runciman
- School of Engineering, University of Guelph, Guelph, ON, Canada
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14
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Sultan S, Acharya Y, Soliman O, Parodi JC, Hynes N. TEVAR and EVAR, the unknown knowns of the cardiovascular hemodynamics; and the immediate and long-term consequences of fabric material on major adverse clinical outcome. Front Surg 2022; 9:940304. [PMID: 36111231 PMCID: PMC9468223 DOI: 10.3389/fsurg.2022.940304] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/11/2022] [Indexed: 11/29/2022] Open
Abstract
This review discusses the impact of endovascular aneurysm repair on cardiovascular (CV) hemodynamics and the role of stent-graft material, i.e., polytetrafluoroethylene (PTFE) vs. polyester in post-procedural outcomes. Endovascular aneurysm repair has been widely employed in the last decades for thoracic and abdominal aneurysm repair. However, aortic endografts are stiff and alter the native flow hemodynamics. This failure to simulate the native aorta could lead to added strain on the heart, manifesting as increased left ventricular strain, higher pulse pressure, and congestive heart failure later. This could result in adverse CV outcomes. Also, evidence is mounting to support the implication of stent-graft materials, i.e., PTFE vs. polyester, in adverse post-procedural outcomes. However, there is an absence of level one evidence. Therefore, the only way forward is to plan and perform a randomised controlled trial to demonstrate the alterations in the CV hemodynamics in the short and long run and compare the available stent-graft materials regarding procedural and clinical outcomes. We believe the best solution, for now, would be to reduce the stented length of the aorta. At the same time, in the longer term, encourage continuous improvement in stent-graft materials and design.
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Affiliation(s)
- Sherif Sultan
- Department of Vascular and Endovascular Surgery, Western Vascular Institute, University Hospital Galway, National University of Ireland, Galway, Ireland
- Galway Clinic, Doughiska, Royal College of Surgeons in Ireland and the National University of Ireland, Galway Affiliated Hospital, Galway, Ireland
- CÚRAM-CORRIB-Vascular Group, National University of Ireland, Galway, Ireland
- Correspondence: Sherif Sultan ,
| | - Yogesh Acharya
- Department of Vascular and Endovascular Surgery, Western Vascular Institute, University Hospital Galway, National University of Ireland, Galway, Ireland
- Galway Clinic, Doughiska, Royal College of Surgeons in Ireland and the National University of Ireland, Galway Affiliated Hospital, Galway, Ireland
| | - Osama Soliman
- CÚRAM-CORRIB-Vascular Group, National University of Ireland, Galway, Ireland
| | - Juan Carlos Parodi
- Department of Vascular Surgery and Biomedical Engineering Department, University of Buenos Aires, Buenos Aires, Argentina
| | - Niamh Hynes
- CÚRAM-CORRIB-Vascular Group, National University of Ireland, Galway, Ireland
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15
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Williamson S, Daniel-Watanabe L, Finnemann J, Powell C, Teed A, Allen M, Paulus M, Khalsa SS, Fletcher PC. The Hybrid Excess and Decay (HED) model: an automated approach to characterising changes in the photoplethysmography pulse waveform. Wellcome Open Res 2022. [DOI: 10.12688/wellcomeopenres.17855.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Photoplethysmography offers a widely used, convenient and non-invasive approach to monitoring basic indices of cardiovascular function, such as heart rate and blood oxygenation. Systematic analysis of the shape of the waveform generated by photoplethysmography might be useful to extract estimates of several physiological and psychological factors influencing the waveform. Here, we developed a robust and automated method for such a systematic analysis across individuals and across different physiological and psychological contexts. We describe a psychophysiologically-relevant model, the Hybrid Excess and Decay (HED) model, which characterises pulse wave morphology in terms of three underlying pressure waves and a decay function. We present the theoretical and practical basis for the model and demonstrate its performance when applied to a pharmacological dataset of 105 participants receiving intravenous administrations of the sympathomimetic drug isoproterenol (isoprenaline). We show that these parameters capture photoplethysmography data with a high degree of precision and, moreover, are sensitive to experimentally-induced changes in interoceptive arousal within individuals. We conclude by discussing the possible value in using the HED model as a complement to standard measures of photoplethysmography signals.
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16
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Parker KH, de Tombe P, van der Velden J, Westerhof BE. The nature of waves in the arteries in memoriam: Nico Westerhof and John Tyberg. J Physiol 2022; 600:4045-4050. [PMID: 35929767 DOI: 10.1113/jp283558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 07/28/2022] [Indexed: 11/08/2022] Open
Abstract
This memorial remembers the lives of two distinguished researchers who made major contributions to cardiovascular physiology; Nico Westerhof (1937-2022) and John Tyberg (1938-2022). It is a joint memorial not because they collaborated closely but because they held very different views about the nature of waves in the arteries. Their papers and particularly their lively discussions at many scientific meetings stimulated interest in the subject. Both were thoughtful and articulate about their views and the debates were polite and dignified. They never resolved their differences and, after outlining what these differences were, we will suggest that perhaps there is no resolution. The authors of this memorial were close to one or the other protagonist; a son, a son-in-law and two close collaborators. We all have different views about the nature of waves in the arteries but we all share great respect for both men and felt that a joint memorial was a fitting way to remember them and their many contributions. All of the authors knew the subjects of this memorial as 'Nico' and 'John' and we will use these informal names throughout. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Kim H Parker
- Department of Bioengineering, Imperial College, Exhibition Road, London, SW7 2AZ, UK
| | - Pieter de Tombe
- Department of Physiology and Biophysics, The University of Illinois at Chicago, Chicago, USA
| | | | - Berend E Westerhof
- Department of Pulmonary Medicine, Amsterdam Universitair Medische Centra, Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, 1081 HV, The Netherlands
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Meng K, Xiao X, Wei W, Chen G, Nashalian A, Shen S, Xiao X, Chen J. Wearable Pressure Sensors for Pulse Wave Monitoring. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109357. [PMID: 35044014 DOI: 10.1002/adma.202109357] [Citation(s) in RCA: 150] [Impact Index Per Article: 75.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/21/2021] [Indexed: 05/15/2023]
Abstract
Cardiovascular diseases remain the leading cause of death worldwide. The rapid development of flexible sensing technologies and wearable pressure sensors have attracted keen research interest and have been widely used for long-term and real-time cardiovascular status monitoring. Owing to compelling characteristics, including light weight, wearing comfort, and high sensitivity to pulse pressures, physiological pulse waveforms can be precisely and continuously monitored by flexible pressure sensors for wearable health monitoring. Herein, an overview of wearable pressure sensors for human pulse wave monitoring is presented, with a focus on the transduction mechanism, microengineering structures, and related applications in pulse wave monitoring and cardiovascular condition assessment. The conceptualizations and methods for the acquisition of physiological and pathological information related to the cardiovascular system are outlined. The biomechanics of arterial pulse waves and the working mechanism of various wearable pressure sensors, including triboelectric, piezoelectric, magnetoelastic, piezoresistive, capacitive, and optical sensors, are also subject to systematic debate. Exemple applications of pulse wave measurement based on microengineering structured devices are then summarized. Finally, a discussion of the opportunities and challenges that wearable pressure sensors face, as well as their potential as a wearable intelligent system for personalized healthcare is given in conclusion.
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Affiliation(s)
- Keyu Meng
- School of Electronic and Information Engineering Jilin Provincial Key Laboratory of Human Health Status Identification and Function Enhancement, Changchun University, Changchun, 130022, China
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Xiao Xiao
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Wenxin Wei
- Department of Anesthesiology, China Medical University, Shenyang, 110022, China
| | - Guorui Chen
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Ardo Nashalian
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Sophia Shen
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Xiao Xiao
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, 90095, USA
| | - Jun Chen
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California, 90095, USA
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18
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Palombo C, Kozakova M, Morizzo C, Losso L, Pagani M, Salvi P, Parker KH, Hughes AD. Carotid Reservoir Pressure Decrease After Prolonged Head Down Tilt Bed Rest in Young Healthy Subjects Is Associated With Reduction in Left Ventricular Ejection Time and Diastolic Length. Front Physiol 2022; 13:866045. [PMID: 35399267 PMCID: PMC8990871 DOI: 10.3389/fphys.2022.866045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 02/10/2022] [Indexed: 01/09/2023] Open
Abstract
Background The arterial pressure waveform reflects the interaction between the heart and the arterial system and carries potentially relevant information about circulatory status. According to the commonly accepted 'wave transmission model', the net BP waveform results from the super-position of discrete forward and backward pressure waves, with the forward wave in systole determined mainly by the left ventricular (LV) ejection function and the backward by the wave reflection from the periphery, the timing and amplitude of which depend on arterial stiffness, the wave propagation speed and the extent of downstream admittance mismatching. However, this approach obscures the 'Windkessel function' of the elastic arteries. Recently, a 'reservoir-excess pressure' model has been proposed, which interprets the arterial BP waveform as a composite of a volume-related 'reservoir' pressure and a wave-related 'excess' pressure. Methods In this study we applied the reservoir-excess pressure approach to the analysis of carotid arterial pressure waveforms (applanation tonometry) in 10 young healthy volunteers before and after a 5-week head down tilt bed rest which induced a significant reduction in stroke volume (SV), end-diastolic LV volume and LV longitudinal function without significant changes in central blood pressure, cardiac output, total peripheral resistance and aortic stiffness. Forward and backward pressure components were also determined by wave separation analysis. Results Compared to the baseline state, bed rest induced a significant reduction in LV ejection time (LVET), diastolic time (DT), backward pressure amplitude (bP) and pressure reservoir integral (INTPR). INTPR correlated directly with LVET, DT, time to the peak of backward wave (bT) and stroke volume, while excess pressure integral (INTXSP) correlated directly with central pressure. Furthermore, Δ.INTPR correlated directly with Δ.LVET, and Δ.DT, and in multivariate analysis INTPR was independently related to LVET and DT and INTXSP to central systolic BP. Conclusion This is an hypothesis generating paper which adds support to the idea that the reservoir-wave hypothesis applied to non-invasively obtained carotid pressure waveforms is of potential clinical usefulness.
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Affiliation(s)
- Carlo Palombo
- Department of Surgical, Medical, Molecular Pathology and Critical Area Medicine, University of Pisa, Pisa, Italy
| | - Michaela Kozakova
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Carmela Morizzo
- Department of Surgical, Medical, Molecular Pathology and Critical Area Medicine, University of Pisa, Pisa, Italy
| | - Lorenzo Losso
- Department of Medical Toxicology Unit and Poison Control Centre, Careggi University Hospital, Florence, Italy
| | - Massimo Pagani
- Department of Medicine, University of Milan, Milan, Italy
| | - Paolo Salvi
- Department of Cardiology, Istituto Auxologico Italiano, IRCCS, Milan, Italy
| | - Kim H. Parker
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Alun D. Hughes
- Department of Population Science and Experimental Medicine, University College of London, London, United Kingdom
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19
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Hashimoto J, Tagawa K, Westerhof BE, Ito S. Central-to-peripheral stiffness gradients determine diastolic pressure and flow fluctuation waveforms: time domain analysis of femoral artery pulse. J Hypertens 2022; 40:338-347. [PMID: 34495902 DOI: 10.1097/hjh.0000000000003014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Blood pressure fluctuates during diastole to create a dicrotic wave but the mechanistic origin remains poorly understood. We sought to investigate the characteristics and determinants of diastolic pressure and flow fluctuations with a focus on stiffness gradients between the central aorta and peripheral arteries. METHODS Using applanation tonometry and duplex ultrasound, pulse waveforms were recorded on the femoral artery in 592 patients (age: 55 ± 14 years) to estimate the diastolic pressure fluctuation as a residual wave against the mono-exponential decay and the diastolic flow fluctuation as a bidirectional (forward and reverse) velocity wave. The radial, carotid, and dorsalis pedis pressures were also recorded to measure the peripheral/aortic pulse pressure (PP) and pulse wave velocity (PWV) ratios. RESULTS There were close resemblances between the femoral pressure and flow fluctuation waveforms. The pressure and flow fluctuations were mutually correlated in relative amplitude as indexed to the total pulse height (r = 0.63), and the former temporally followed the latter. In multivariate-adjusted models, higher peripheral/aortic PP and PWV ratios were independently associated with greater pressure and flow fluctuation indices (P < 0.001). Mediation analysis revealed that the associations of PP and PWV ratios with the pressure fluctuation index were largely mediated by the flow fluctuation index [indirect/total effect ratio: 57 (95% CI 42-80)% and 54 (30-100)%, respectively]. CONCLUSION These results suggest that central-to-peripheral pulse amplification and stiffness gradients contribute to triphasic flow fluctuations and dicrotic pressure waves. Diminished or inverted stiffness gradients caused by aortic stiffening may thus reduce diastolic runoff leading to ischemic organ damage.
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Affiliation(s)
- Junichiro Hashimoto
- Medical Center, Miyagi University of Education
- Division of Nephrology, Endocrinology, and Vascular Medicine, Department of Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | | | - Berend E Westerhof
- Department of Pulmonary Medicine, Amsterdam Cardiovascular Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Sadayoshi Ito
- Division of Nephrology, Endocrinology, and Vascular Medicine, Department of Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
- Katta General Hospital, Shiroishi, Japan
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20
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Dewi E, Hadiyoso S, Mengko TER, Zakaria H, Astami K. Cardiovascular system modeling using windkessel segmentation model based on photoplethysmography measurements of fingers and toes. JOURNAL OF MEDICAL SIGNALS & SENSORS 2022; 12:192-201. [PMID: 36120404 PMCID: PMC9480512 DOI: 10.4103/jmss.jmss_101_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 02/13/2022] [Accepted: 02/22/2022] [Indexed: 11/18/2022]
Abstract
Background: Photoplethysmography (PPG) contains information about the health condition of the heart and blood vessels. Cardiovascular system modeling using PPG signal measurements can represent, analyze, and predict the cardiovascular system. Methods: This study aims to make a cardiovascular system model using a Windkessel model by dividing the blood vessels into seven segments. This process involves the PPG signal of the fingertips and toes for further analysis to obtain the condition of the elasticity of the blood vessels as the main parameter. The method is to find the Resistance, Inductance, and Capacitance (RLC) value of each segment of the body through the equivalent equation between the electronic unit and the cardiovascular unit. The modeling made is focused on PPG parameters in the form of stiffness index, the time delay (△t), and augmentation index. Results: The results of the model simulation using PSpice were then compared with the results of measuring the PPG signal to analyze changes in the behavior of the PPG signal taken from ten healthy people with an average age of 46 years, compared to ten cardiac patients with an average age of 48 years. It is found that decreasing 20% of capacitance value and the arterial stiffness parameter will close to cardiac patients' data. Compared with the measurement results, the correlation of the PPG signal in the simulation model is more than 0.9. Conclusions: The proposed model is expected to be used in the early detection of arterial stiffness. It can also be used to study the dynamics of the cardiovascular system, including changes in blood flow velocity and blood pressure.
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21
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Fortier C, Garneau CA, Paré M, Obeid H, Côté N, Duval K, Goupil R, Agharazii M. Modulation of Arterial Stiffness Gradient by Acute Administration of Nitroglycerin. Front Physiol 2021; 12:774056. [PMID: 34975528 PMCID: PMC8715004 DOI: 10.3389/fphys.2021.774056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/12/2021] [Indexed: 11/16/2022] Open
Abstract
Background: Physiologically, the aorta is less stiff than peripheral conductive arteries, creating an arterial stiffness gradient, protecting microcirculation from high pulsatile pressure. However, the pharmacological manipulation of arterial stiffness gradient has not been thoroughly investigated. We hypothesized that acute administration of nitroglycerin (NTG) may alter the arterial stiffness gradient through a more significant effect on the regional stiffness of medium-sized muscular arteries, as measured by pulse wave velocity (PWV). The aim of this study was to examine the differential impact of NTG on regional stiffness, and arterial stiffness gradient as measured by the aortic-brachial PWV ratio (AB-PWV ratio) and aortic-femoral PWV ratio (AF-PWV ratio). Methods: In 93 subjects (age: 61 years, men: 67%, chronic kidney disease [CKD]: 41%), aortic, brachial, and femoral stiffnesses were determined by cf-PWV, carotid-radial (cr-PWV), and femoral-dorsalis pedis artery (fp-PWV) PWVs, respectively. The measurements were repeated 5 min after the sublingual administration of NTG (0.4 mg). The AB-PWV and AF-PWV ratios were obtained by dividing cf-PWV by cr-PWV or fp-PWV, respectively. The central pulse wave profile was determined by radial artery tonometry through the generalized transfer function. Results: At baseline, cf-PWV, cr-PWV, and fp-PWV were 12.12 ± 3.36, 9.51 ± 1.81, and 9.71 ± 1.89 m/s, respectively. After the administration of NTG, there was a significant reduction in cr-PWV of 0.86 ± 1.27 m/s (p < 0.001) and fp-PWV of 1.12 ± 1.74 m/s (p < 0.001), without any significant changes in cf-PWV (p = 0.928), leading to a significant increase in the AB-PWV ratio (1.30 ± 0.39 vs. 1.42 ± 0.46; p = 0.001) and AF-PWV ratio (1.38 ± 0.47 vs. 1.56 ± 0.53; p = 0.001). There was a significant correlation between changes in the AF-PWV ratio and changes in the timing of wave reflection (r = 0.289; p = 0.042) and the amplitude of the heart rate-adjusted augmented pressure (r = − 0.467; p < 0.001). Conclusion: This study shows that acute administration of NTG reduces PWV of muscular arteries (brachial and femoral) without modifying aortic PWV. This results in an unfavorable profile of AB-PWV and AF-PWV ratios, which could lead to higher pulse pressure transmission into the microcirculation.
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Affiliation(s)
- Catherine Fortier
- CHU de Québec Research Center-Université Laval, L’Hôtel-Dieu de Québec Hospital, Québec, QC, Canada
- Division of Nephrology, Faculty of Medicine, Université Laval, Québec, QC, Canada
- Research Center of the Hôpital du Sacré-Coeur de Montréal, Montréal, QC, Canada
| | - Charles-Antoine Garneau
- CHU de Québec Research Center-Université Laval, L’Hôtel-Dieu de Québec Hospital, Québec, QC, Canada
- Division of Nephrology, Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Mathilde Paré
- CHU de Québec Research Center-Université Laval, L’Hôtel-Dieu de Québec Hospital, Québec, QC, Canada
- Division of Nephrology, Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Hasan Obeid
- CHU de Québec Research Center-Université Laval, L’Hôtel-Dieu de Québec Hospital, Québec, QC, Canada
| | - Nadège Côté
- CHU de Québec Research Center-Université Laval, L’Hôtel-Dieu de Québec Hospital, Québec, QC, Canada
- Division of Nephrology, Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Karine Duval
- CHU de Québec Research Center-Université Laval, L’Hôtel-Dieu de Québec Hospital, Québec, QC, Canada
| | - Rémi Goupil
- Research Center of the Hôpital du Sacré-Coeur de Montréal, Montréal, QC, Canada
| | - Mohsen Agharazii
- CHU de Québec Research Center-Université Laval, L’Hôtel-Dieu de Québec Hospital, Québec, QC, Canada
- Division of Nephrology, Faculty of Medicine, Université Laval, Québec, QC, Canada
- *Correspondence: Mohsen Agharazii,
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22
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Augustin CM, Gsell MA, Karabelas E, Willemen E, Prinzen FW, Lumens J, Vigmond EJ, Plank G. A computationally efficient physiologically comprehensive 3D-0D closed-loop model of the heart and circulation. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2021; 386:114092. [PMID: 34630765 PMCID: PMC7611781 DOI: 10.1016/j.cma.2021.114092] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Computer models of cardiac electro-mechanics (EM) show promise as an effective means for the quantitative analysis of clinical data and, potentially, for predicting therapeutic responses. To realize such advanced applications methodological key challenges must be addressed. Enhanced computational efficiency and robustness is crucial to facilitate, within tractable time frames, model personalization, the simulation of prolonged observation periods under a broad range of conditions, and physiological completeness encompassing therapy-relevant mechanisms is needed to endow models with predictive capabilities beyond the mere replication of observations. Here, we introduce a universal feature-complete cardiac EM modeling framework that builds on a flexible method for coupling a 3D model of bi-ventricular EM to the physiologically comprehensive 0D CircAdapt model representing atrial mechanics and closed-loop circulation. A detailed mathematical description is given and efficiency, robustness, and accuracy of numerical scheme and solver implementation are evaluated. After parameterization and stabilization of the coupled 3D-0D model to a limit cycle under baseline conditions, the model's ability to replicate physiological behaviors is demonstrated, by simulating the transient response to alterations in loading conditions and contractility, as induced by experimental protocols used for assessing systolic and diastolic ventricular properties. Mechanistic completeness and computational efficiency of this novel model render advanced applications geared towards predicting acute outcomes of EM therapies feasible.
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Affiliation(s)
- Christoph M. Augustin
- Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Matthias A.F. Gsell
- Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Elias Karabelas
- Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Erik Willemen
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, Netherlands
| | - Frits W. Prinzen
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, Netherlands
| | - Joost Lumens
- Department of Biomedical Engineering, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, Netherlands
| | - Edward J. Vigmond
- IHU Liryc, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac-Bordeaux, France
| | - Gernot Plank
- Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Correspondence to: Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/IV, Graz 8010, Austria. (G. Plank)
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23
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Vennin S, Li Y, Mariscal-Harana J, Charlton PH, Fok H, Gu H, Chowienczyk P, Alastruey J. Novel Pressure Wave Separation Analysis for Cardiovascular Function Assessment Highlights Major Role of Aortic Root. IEEE Trans Biomed Eng 2021; 69:1707-1716. [PMID: 34767501 PMCID: PMC7612937 DOI: 10.1109/tbme.2021.3127799] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Objective A novel method was presented to separate the central blood pressure wave (CBPW) into five components with different biophysical and temporal origins. It includes a time-varying emission coefficient (γ) that quantifies pulse wave generation and reflection at the aortic root. Methods The method was applied to normotensive subjects with modulated physiology by inotropic/vasoactive drugs (n = 13), hypertensive subjects (n = 158), and virtual subjects (n = 4,374). Results γ is directly proportional to aortic flow throughout the cardiac cycle. Mean peak γ increased with increasing pulse pressure (from <30 to >70 mmHg) in the hypertensive (from 1.6 to 2.5, P < 0.001) and in silico (from 1.4 to 2.8, P < 0.001) groups, dobutamine dose (from baseline to 7.5 μg/kg/min) in the normotensive group (from 2.1 to 2.7, P < 0.05), and remained unchanged when peripheral wave reflections were suppressed in silico. This was accompanied by an increase in the percentage contribution of the cardiac-aortic-coupling component of CBPW in systole: from 11% to 23% (P < 0.001) in the hypertensive group, 9% to 21% (P < 0.001) in the in silico group, and 17% to 23% (P < 0.01) in the normotensive group. Conclusion These results suggest that the aortic root is a major reflection site in the systemic arterial network and ventricular-aortic coupling is the main determinant in the elevation of pulsatile pulse pressure. Significance Ventricular-aortic coupling is a prime therapeutic target for preventing/treating systolic hypertension.
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Aghilinejad A, Amlani F, Liu J, Pahlevan NM. Accuracy and applicability of non-invasive evaluation of aortic wave intensity using only pressure waveforms in humans. Physiol Meas 2021; 42. [PMID: 34521071 DOI: 10.1088/1361-6579/ac2671] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/14/2021] [Indexed: 01/09/2023]
Abstract
Background.Wave intensity (WI) analysis is a well-established method for quantifying the energy carried in arterial waves, providing valuable clinical information about cardiovascular function. The primary drawback of this method is the need for concurrent measurements of both pressure and flow waveforms.Objective. We have for the first time investigated the accuracy of a novel methodology for estimating wave intensity employing only single pressure waveform measurements; we studied both carotid- and radial-based estimations in a large heterogeneous cohort.Approach.Tonometry was performed alongside Doppler ultrasound to acquire measurements of both carotid and radial pressure waveforms as well as aortic flow waveforms in 2640 healthy and diseased participants (1439 female) in the Framingham Heart Study. Patterns consisting of two forward waves (Wf1, Wf2) and one backward wave (Wb1) along with reflection metrics were compared with those obtained from exact WI analysis.Main Results. Carotid-based estimates correlated well for forward peak amplitudes (Wf1,r = 0.85,p < 0.05; Wf2,r = 0.72,p < 0.05) and peak time (Wf1,r = 0.94,p < 0.05; Wf2,r = 0.98,p < 0.05), and radial-based estimates correlated fairly to poorly for amplitudes (Wf1,r = 0.62,p < 0.05; Wf2,r = 0.42,p < 0.05) and peak time (Wf1,r = 0.04,p = 0.10; Wf2,r = 0.75,p < 0.05). In all cases, estimated Wb1 measures were not correlated. Reflection metrics were well correlated for healthy patients (r = 0.67,p < 0.05), moderately correlated for valvular disease (r = 0.59,p < 0.05) and fairly correlated for CVD (r = 0.46,p < 0.05) and heart failure (r = 0.49,p < 0.05).Significance. These findings indicate that pressure-only WI produces accurate results only when forward contributions are of primary interest and only for carotid pressure waveforms. The pressure-only WI estimations of this work provide an important opportunity to further the goal of uncovering clinical insights through wave analysis affordably and non-invasively.
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Affiliation(s)
- Arian Aghilinejad
- Department of Aerospace & Mechanical Engineering, University of Southern California, Los Angeles, United States of America
| | - Faisal Amlani
- Department of Aerospace & Mechanical Engineering, University of Southern California, Los Angeles, United States of America
| | - Jing Liu
- Department of Aerospace & Mechanical Engineering, University of Southern California, Los Angeles, United States of America
| | - Niema M Pahlevan
- Department of Aerospace & Mechanical Engineering, University of Southern California, Los Angeles, United States of America.,Division of Cardiovascular Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, United States of America
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25
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Kim H, Kim IC, Hwang J, Lee CH, Cho YK, Park HS, Chung JW, Nam CW, Han S, Hur SH. Features and implications of higher systolic central than peripheral blood pressure in patients at very high risk of atherosclerotic cardiovascular disease. J Hum Hypertens 2021; 35:994-1002. [PMID: 33408327 DOI: 10.1038/s41371-020-00472-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 02/03/2023]
Abstract
Peripheral blood pressure (PBP) is usually higher than central blood pressure (CBP) due to pulse amplification; however, it is not well understood why cuff-measured PBP can be lower than CBP estimated by the late systolic pressure of radial pulse waves. We explored the implications of systolic PBP-CBP (P-CBP) differences for cardiovascular (CV) prognosis. In total, 335 patients at very high risk of atherosclerotic cardiovascular disease (ASCVD) underwent automated applanation tonometry and brachial-ankle pulse wave velocity (baPWV), and they were classified into groups according to positive or negative systolic P-CBP differences. Between-group characteristics and clinical outcomes (the composite of coronary revascularization, stroke, heart failure hospitalization, and CV death) were evaluated. Patients with negative differences had significantly higher frequency of hypertension, coronary artery disease, higher ASCVD risk burden, and elevated N-terminal pro b-type natriuretic peptide. They had higher left atrial volume index (LAVI) and lower systolic mitral septal tissue velocity (TVI-s') than those with a positive difference. These patients showed higher systolic PBP and CBP, and a higher baPWV. Multivariable analysis indicated that TVI-s', LAVI, and ASCVD risk burden were independent determinants of such systolic P-CBP differences. During a median follow-up of 12.6 months, clinical outcomes were significantly related to a negative difference (11.5% vs. 3.4%, p = 0.014), and a systolic P-CBP difference ≤ -8 mmHg was associated with a threefold higher likelihood of poor prognosis. In patients at very high risk of ASCVD, systolic P-CBP difference was associated with cardiac dysfunction and ASCVD risk burden, allowing further risk stratification.
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Affiliation(s)
- Hyungseop Kim
- Division of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea.
| | - In-Cheol Kim
- Division of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Jongmin Hwang
- Division of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Cheol Hyun Lee
- Division of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Yun-Kyeong Cho
- Division of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Hyoung-Seob Park
- Division of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Jin-Wook Chung
- Division of Cardiology, Department of Internal Medicine, Keimyung University Daegu Dongsan Hospital, Daegu, Republic of Korea
| | - Chang-Wook Nam
- Division of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Seongwook Han
- Division of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
| | - Seung-Ho Hur
- Division of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Republic of Korea
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26
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Sultan S, Acharya Y, Hazima M, Salahat H, Parodi JC, Hynes N. Combined thoracic endovascular aortic repair and endovascular aneurysm repair and the long-term consequences of altered cardiovascular haemodynamics on morbidity and mortality: case series and literature review. EUROPEAN HEART JOURNAL-CASE REPORTS 2021; 5:ytab339. [PMID: 34622129 PMCID: PMC8493011 DOI: 10.1093/ehjcr/ytab339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/18/2021] [Accepted: 08/13/2021] [Indexed: 11/14/2022]
Abstract
Background Thoracic and abdominal aortic stent grafts are firmer and more rigid than the native aorta. Aortic implanted devices have been implicated in the development of acute systolic hypertension, elevated pulse pressure, and reduced coronary perfusion. Case summary We report four cases of staged thoracic endovascular aortic repair (TEVAR) and then endovascular aneurysm repair (EVAR). All patients had TEVAR first for thoracic aortic aneurysm and later on developed infra-renal abdominal aortic aneurysm (AAA) that required EVAR. There were three males and one female with a median age of 74.5 years (range 67.5-78.5). None of the patients developed aortic-related major clinical adverse effects or required any aortic intervention during their follow-up. However, within 2 years, all patients developed symptomatic left ventricular hypertrophy with diastolic dysfunction. All patients had bilateral lower limb oedema, with on and off chest pain and shortness of breath (SOB), necessitating coronary angiograms, which showed no evidence of coronary artery disease. Three patients died from cardiovascular-related morbidities, and the fourth patient is still complaining of SOB despite a normal coronary angiogram. Discussion Aortic-endograft compliance mismatch is an invisible enemy, with troubling consequences for the aorta proximal and distal to the endograft. Aortic stiffness due to vascular endograft could lead to cardiovascular adverse events, even in the absence of direct aortic-related complications. After combined TEVAR and EVAR, the compliance mismatch and elasticity loss are even more pronounced than with TEVAR alone, which necessitates patient monitoring for the development of cardiovascular complications.
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Affiliation(s)
- Sherif Sultan
- Western Vascular Institute, Department of Vascular and Endovascular Surgery, University Hospital Galway, National University of Ireland, Newcastle Road, Galway H91 YR71, Ireland.,Department of Vascular and Endovascular Surgery, Galway Clinic, Doughiska, Royal College of Surgeons in Ireland and the National University of Ireland, Galway Affiliated Hospital, Ireland
| | - Yogesh Acharya
- Western Vascular Institute, Department of Vascular and Endovascular Surgery, University Hospital Galway, National University of Ireland, Newcastle Road, Galway H91 YR71, Ireland.,Department of Vascular and Endovascular Surgery, Galway Clinic, Doughiska, Royal College of Surgeons in Ireland and the National University of Ireland, Galway Affiliated Hospital, Ireland
| | - Mohiey Hazima
- Western Vascular Institute, Department of Vascular and Endovascular Surgery, University Hospital Galway, National University of Ireland, Newcastle Road, Galway H91 YR71, Ireland
| | - Hiba Salahat
- Department of Vascular and Endovascular Surgery, Galway Clinic, Doughiska, Royal College of Surgeons in Ireland and the National University of Ireland, Galway Affiliated Hospital, Ireland
| | - Juan Carlos Parodi
- Department of Vascular Surgery and Biomedical Engineering Department, Alma mater, University of Buenos Aires, Wake Forest University, Washington University in St. Louis, and Trinidad Hospital, Buenos Aires, Argentina
| | - Niamh Hynes
- Department of Vascular and Endovascular Surgery, Galway Clinic, Doughiska, Royal College of Surgeons in Ireland and the National University of Ireland, Galway Affiliated Hospital, Ireland
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27
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Wustmann K, Constantine A, Davies J, Li W, Pennell D, Wort S, Kempny A, Price L, McCabe C, Mohiaddin R, Francis D, Gatzoulis M, Dimopoulos K. Prognostic implications of pulmonary wave reflection and reservoir pressure in patients with pulmonary hypertension. INTERNATIONAL JOURNAL OF CARDIOLOGY CONGENITAL HEART DISEASE 2021. [DOI: 10.1016/j.ijcchd.2021.100199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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Armstrong MK, Schultz MG, Hughes AD, Picone DS, Sharman JE. Physiological and clinical insights from reservoir-excess pressure analysis. J Hum Hypertens 2021; 35:758-768. [PMID: 33750902 PMCID: PMC7611663 DOI: 10.1038/s41371-021-00515-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 02/10/2021] [Accepted: 02/18/2021] [Indexed: 01/31/2023]
Abstract
There is a growing body of evidence indicating that reservoir-excess pressure model parameters provide physiological and clinical insights above and beyond standard blood pressure (BP) and pulse waveform analysis. This information has never been collectively examined and was the aim of this review. Cardiovascular disease is the leading cause of mortality worldwide, with BP as the greatest cardiovascular disease risk factor. However, brachial systolic and diastolic BP provide limited information on the underlying BP waveform, missing important BP-related cardiovascular risk. A comprehensive analysis of the BP waveform is provided by parameters derived via the reservoir-excess pressure model, which include reservoir pressure, excess pressure, and systolic and diastolic rate constants and Pinfinity. These parameters, derived from the arterial BP waveform, provide information on the underlying arterial physiology and ventricular-arterial interactions otherwise missed by conventional BP and waveform indices. Application of the reservoir-excess pressure model in the clinical setting may facilitate a better understanding and earlier identification of cardiovascular dysfunction associated with disease. Indeed, reservoir-excess pressure parameters have been associated with sub-clinical markers of end-organ damage, cardiac and vascular dysfunction, and future cardiovascular events and mortality beyond conventional risk factors. In the future, greater understanding is needed on how the underlying physiology of the reservoir-excess pressure parameters informs cardiovascular disease risk prediction over conventional BP and waveform indices. Additional consideration should be given to the application of the reservoir-excess pressure model in clinical practice using new technologies embedded into conventional BP assessment methods.
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Affiliation(s)
- Matthew K Armstrong
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Martin G Schultz
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Alun D Hughes
- MRC Unit for Lifelong Health & Aging, Institute of Cardiovascular Science, University College London, London, UK
| | - Dean S Picone
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - James E Sharman
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia.
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29
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Tyberg JV. Wave propagation and reflection in the aorta and implications of the aortic Windkessel. EXPLORATION OF MEDICINE 2021. [DOI: 10.37349/emed.2021.00042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Some have said that it is inappropriate and perhaps impossible to consider wave and Windkessel phenomena simultaneously. For 50 years, arterial hemodynamics has been dominated by the frequency-domain “impedance analysis” in which it was assumed that all variations in aortic pressure and flow were caused only by forward- and backward-going waves. This paper is a review of the results of incorporating the effects of Frank’s Windkessel. We have taken the view that measured aortic pressure is the sum of a Windkessel component and forward-going and backward-going wave components. When the Windkessel component is initially subtracted out, the pattern of propagation and reflection of wave components becomes clear. Furthermore, this analysis obviates the implications of impedance analysis that have not been explained satisfactorily.
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Affiliation(s)
- John V. Tyberg
- Emeritus Professor of Cardiac Sciences and Physiology/Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada
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30
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Aboelkassem Y, Savic D. Particle swarm optimizer for arterial blood flow models. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 201:105933. [PMID: 33517234 DOI: 10.1016/j.cmpb.2021.105933] [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: 08/28/2020] [Accepted: 01/05/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Mathematical modeling and computational simulations of arterial blood flow network can offer an insilico platform for both diagnostics and therapeutic phases of patients that suffer from cardiac diseases. These models are normally complex and involve many unknown parameters. For physiological relevance, these parameters should be optimized using in-vivo human/animal data sets. The main goal of this work is to develop an efficient, yet an accurate optimization algorithm to compute parameters in the arterial blood flow models. METHODS The particle swarm optimization (PSO) method is proposed herein for the first time, as an accurate algorithm that applies to computing parameters in the Windkessel type model of blood flow in the arterial system. We begin by defining a 6-element Windkessel (WK6) arterial flow model, which is then implemented and validated using multiple flow rate and aortic pressure measurements obtained from different subjects including dogs, pigs and humans. The parameters in the model are obtained using the PSO technique which minimizes the pressure root mean square (P-RMS) error between the computed and the measured aortic pressure waveform. RESULTS Model parameters obtained using the proposed PSO method were able to recover the pressure waveform in the aorta during the cardiac cycle for both healthy and diseased species (animals/humans). The PSO method provides an accurate approach to solve this challenging multi-dimensional parameter identification problem. The results obtained by PSO algorithm was compared with the classical gradient-based, namely the non-linear square fit (NLSF) algorithm. CONCLUSIONS The results indicate that the PSO method offers alternative and accurate method to find optimal physiological parameters involved in the Windkessel model for the study of arterial blood flow network. The PSO method has performed better than the NLSF approach as depicted from the P-RMS calculations. Finally, we believe that the PSO method offers a great potential and could be used for many other biomedicine optimization problems.
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Affiliation(s)
| | - Dragana Savic
- Radcliffe Department of Medicine, University of Oxford, UK
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31
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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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Giosa L, Busana M, Payen D. Pitfalls in the assessment of ventriculo-arterial coupling from peripheral waveform analysis in septic shock. Comment on Br J Anaesth 2020; 125: 1018-1024. Br J Anaesth 2021; 126:e101-e102. [PMID: 33422286 DOI: 10.1016/j.bja.2020.12.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 11/27/2020] [Accepted: 12/08/2020] [Indexed: 11/30/2022] Open
Affiliation(s)
- Lorenzo Giosa
- Department of Surgical Sciences, University of Turin, Turin, Italy.
| | - Mattia Busana
- Department of Anesthesiology, University Medical Center of Göttingen, Göttingen, Germany
| | - Didier Payen
- University of Paris 7, Denis Diderot, Paris, France
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33
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Cooper LL, Rong J, Pahlevan NM, Rinderknecht DG, Benjamin EJ, Hamburg NM, Vasan RS, Larson MG, Gharib M, Mitchell GF. Intrinsic Frequencies of Carotid Pressure Waveforms Predict Heart Failure Events: The Framingham Heart Study. Hypertension 2021; 77:338-346. [PMID: 33390053 PMCID: PMC7803452 DOI: 10.1161/hypertensionaha.120.15632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Supplemental Digital Content is available in the text. Intrinsic frequencies (IFs) derived from arterial waveforms are associated with cardiovascular performance, aging, and prevalent cardiovascular disease (CVD). However, prognostic value of these novel measures is unknown. We hypothesized that IFs are associated with incident CVD risk. Our sample was drawn from the Framingham Heart Study Original, Offspring, and Third Generation Cohorts and included participants free of CVD at baseline (N=4700; mean age 52 years, 55% women). We extracted 2 dominant frequencies directly from a series of carotid pressure waves: the IF of the coupled heart and vascular system during systole (ω1) and the IF of the decoupled vasculature during diastole (ω2). Total frequency variation (Δω) was defined as the difference between ω1 and ω2. We used Cox proportional hazards regression models to relate IFs to incident CVD events during a mean follow-up of 10.6 years. In multivariable models adjusted for CVD risk factors, higher ω1 (hazard ratio [HR], 1.14 [95% CI], 1.03–1.26]; P=0.01) and Δω (HR, 1.16 [95% CI, 1.03–1.30]; P=0.02) but lower ω2 (HR, 0.87 [95% CI, 0.77–0.99]; P=0.03) were associated with higher risk for incident composite CVD events. In similarly adjusted models, higher ω1 (HR, 1.23 [95% CI, 1.07–1.42]; P=0.004) and Δω (HR, 1.26 [95% CI, 1.05–1.50]; P=0.01) but lower ω2 (HR, 0.81 [95% CI, 0.66–0.99]; P=0.04) were associated with higher risk for incident heart failure. IFs were not significantly associated with incident myocardial infarction or stroke. Novel IFs may represent valuable markers of heart failure risk in the community.
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Affiliation(s)
- Leroy L Cooper
- From the Biology Department, Vassar College, Poughkeepsie, NY (L.L.C.)
| | - Jian Rong
- Boston University and NHLBI's Framingham Heart Study, MA (J.R., E.J.B., R.S.V., M.G.L.)
| | - Niema M Pahlevan
- Department of Aerospace and Mechanical Engineering (N.M.P.), University of Southern California, Los Angeles.,Division of Cardiovascular Medicine, Department of Medicine, Keck School of Medicine (N.M.P.), University of Southern California, Los Angeles
| | - Derek G Rinderknecht
- Graduate Aerospace Laboratories, Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena (D.G.R., M.G.)
| | - Emelia J Benjamin
- Boston University and NHLBI's Framingham Heart Study, MA (J.R., E.J.B., R.S.V., M.G.L.).,Cardiology and Preventive Medicine Sections, Department of Medicine (E.J.B., R.S.V.), Boston University School of Medicine, MA.,Evans Department of Medicine (E.J.B., N.M.H., R.S.V.), Boston University School of Medicine, MA.,Whitaker Cardiovascular Institute (E.J.B., N.M.H., R.S.V.), Boston University School of Medicine, MA.,Department of Epidemiology (E.J.B., R.S.V.), Boston University School of Public Health, MA
| | - Naomi M Hamburg
- Evans Department of Medicine (E.J.B., N.M.H., R.S.V.), Boston University School of Medicine, MA.,Whitaker Cardiovascular Institute (E.J.B., N.M.H., R.S.V.), Boston University School of Medicine, MA
| | - Ramachandran S Vasan
- Boston University and NHLBI's Framingham Heart Study, MA (J.R., E.J.B., R.S.V., M.G.L.).,Cardiology and Preventive Medicine Sections, Department of Medicine (E.J.B., R.S.V.), Boston University School of Medicine, MA.,Evans Department of Medicine (E.J.B., N.M.H., R.S.V.), Boston University School of Medicine, MA.,Whitaker Cardiovascular Institute (E.J.B., N.M.H., R.S.V.), Boston University School of Medicine, MA.,Department of Epidemiology (E.J.B., R.S.V.), Boston University School of Public Health, MA
| | - Martin G Larson
- Boston University and NHLBI's Framingham Heart Study, MA (J.R., E.J.B., R.S.V., M.G.L.).,Department of Biostatistics (M.G.L.), Boston University School of Public Health, MA
| | - Morteza Gharib
- Graduate Aerospace Laboratories, Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena (D.G.R., M.G.).,Department of Medical Engineering, California Institute of Technology, Pasadena (M.G.)
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Brachial-cuff excess pressure is associated with carotid intima-media thickness among Australian children: a cross-sectional population study. Hypertens Res 2020; 44:541-549. [PMID: 33162551 DOI: 10.1038/s41440-020-00576-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 08/31/2020] [Accepted: 10/02/2020] [Indexed: 11/08/2022]
Abstract
Reservoir pressure parameters (i.e., reservoir pressure [RP] and excess pressure [XSP]) independently predict cardiovascular events in adults, but this has not been investigated in children. This study aimed to determine (1) the association of reservoir pressure parameters with carotid intima-media thickness (carotid IMT), a preclinical vascular phenotype, and (2) whether a multivariable regression model with or without reservoir pressure parameters fits better for estimating carotid IMT in children. Study participants were 11-12-year-old children (n = 1231, 50% male) from the Child Health CheckPoint study, a cross-sectional substudy of the population-based Longitudinal Study of Australian Children. RP and XSP were obtained using brachial-cuff oscillometry (SphygmoCor XCEL, AtCor, Sydney). Carotid IMT was quantified by vascular ultrasonography. XSP was associated with carotid IMT after adjusting for confounders including age, sex, BMI z-score, heart rate, pubertal stage, moderate-to-vigorous physical activity, and mean arterial pressure (β = 0.93 µm, 95% CI 0.30-1.56 for XSP peak and β = 0.04 µm, 95% CI 0.01-0.08 for XSP integral). The results of the likelihood ratio test indicated a trend that the model with XSP and the above confounders fit better than a similar model without XSP for estimating carotid IMT. Our findings indicate that brachial-cuff device-measured XSP is associated with carotid IMT independent of conventional cardiovascular risk factors, including standard BP. This implies that a clinically convenient cuff approach could provide meaningful information for the early assessment of cardiovascular risk among children.
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Pomella N, Rietzschel ER, Segers P, Khir AW. Impact of varying diastolic pressure fitting technique for the reservoir-wave model on wave intensity analysis. Proc Inst Mech Eng H 2020; 234:1300-1311. [PMID: 32996433 PMCID: PMC7675780 DOI: 10.1177/0954411920959957] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 08/27/2020] [Indexed: 01/09/2023]
Abstract
The reservoir-wave model assumes that the measured arterial pressure is made of two components: reservoir and excess. The effect of the reservoir volume should be excluded to quantify the effects of forward and backward traveling waves on blood pressure. Whilst the validity of the reservoir-wave concept is still debated, there is no consensus on the best fitting method for the calculation of the reservoir pressure waveform. Therefore, the aim of this parametric study is to examine the effects of varying the fitting technique on the calculation of reservoir and excess components of pressure and velocity waveforms. Common carotid pressure and flow velocity were measured using applanation tonometry and doppler ultrasound, respectively, in 1037 healthy humans collected randomly from the Asklepios population, aged 35 to 55 years old. Different fitting techniques to the diastolic decay of the measured arterial pressure were used to determine the asymptotic pressure decay, which in turn was used to determine the reservoir pressure waveform. The corresponding wave speed was determined using the PU-loop method, and wave intensity parameters were calculated and compared. Different fitting methods resulted in significant changes in the shape of the reservoir pressure waveform; however, its peak and time integral remained constant in this study. Although peak and integral of excess pressure, velocity components and wave intensity changed significantly with changing the diastolic decay fitting method, wave speed was not substantially modified. We conclude that wave speed, peak reservoir pressure and its time integral are independent of the diastolic pressure decay fitting techniques examined in this study. Therefore, these parameters are considered more reliable diagnostic indicators than excess pressure and velocity which are more sensitive to fitting techniques.
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Affiliation(s)
- Nicola Pomella
- Biomedical Engineering Research Group, Brunel University London, UK
- Centre for Genomics and Child Health, Blizard Institute, Queen Mary University of London, UK
- Current affiliation: Centre for Genomics and Child Health, Blizard Institute, Queen Mary University of London, UK
| | - Ernst R Rietzschel
- Department of Cardiovascular Diseases, Ghent University Hospital, Ghent, Belgium
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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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37
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Michel JB. Phylogenic Determinants of Cardiovascular Frailty, Focus on Hemodynamics and Arterial Smooth Muscle Cells. Physiol Rev 2020; 100:1779-1837. [DOI: 10.1152/physrev.00022.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The evolution of the circulatory system from invertebrates to mammals has involved the passage from an open system to a closed in-parallel system via a closed in-series system, accompanying the increasing complexity and efficiency of life’s biological functions. The archaic heart enables pulsatile motion waves of hemolymph in invertebrates, and the in-series circulation in fish occurs with only an endothelium, whereas mural smooth muscle cells appear later. The present review focuses on evolution of the circulatory system. In particular, we address how and why this evolution took place from a closed, flowing, longitudinal conductance at low pressure to a flowing, highly pressurized and bifurcating arterial compartment. However, although arterial pressure was the latest acquired hemodynamic variable, the general teleonomy of the evolution of species is the differentiation of individual organ function, supported by specific fueling allowing and favoring partial metabolic autonomy. This was achieved via the establishment of an active contractile tone in resistance arteries, which permitted the regulation of blood supply to specific organ activities via its localized function-dependent inhibition (active vasodilation). The global resistance to viscous blood flow is the peripheral increase in frictional forces caused by the tonic change in arterial and arteriolar radius, which backscatter as systemic arterial blood pressure. Consequently, the arterial pressure gradient from circulating blood to the adventitial interstitium generates the unidirectional outward radial advective conductance of plasma solutes across the wall of conductance arteries. This hemodynamic evolution was accompanied by important changes in arterial wall structure, supported by smooth muscle cell functional plasticity, including contractility, matrix synthesis and proliferation, endocytosis and phagocytosis, etc. These adaptive phenotypic shifts are due to epigenetic regulation, mainly related to mechanotransduction. These paradigms actively participate in cardio-arterial pathologies such as atheroma, valve disease, heart failure, aneurysms, hypertension, and physiological aging.
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38
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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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Mueller N, Streis J, Müller S, Pavenstädt H, Felderhoff T, Reuter S, Busch V. Pulse Wave Analysis and Pulse Wave Velocity for Fistula Assessment. Kidney Blood Press Res 2020; 45:576-588. [PMID: 32575106 DOI: 10.1159/000506741] [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] [Received: 05/15/2019] [Accepted: 02/19/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND/AIMS Pulse wave analysis (PWA) and pulse wave velocity (PWV) provide information about arterial stiffness and elasticity, which is mainly used for cardiovascular risk stratification. In the presented prospective observational pilot study, we examined the hypothesis that radiocephalic fistula (RCF)-related changes of haemodynamics and blood vessel morphology including high as well as low flow can be seen in specific changes of pulse wave (PW) morphology. METHODS Fifty-six patients with RCF underwent local ambilateral peripheral PWA and PWV measurement with the SphygmoCor® device. Given that the output parameters of the SphygmoCor® are not relevant for the study objectives, we defined new suitable parameters for PWA in direct proximity to fistulas and established an appropriate analysing algorithm. Duplex sonography served as reference method. RESULTS Marked changes of peripheral PW morphology when considering interarm differences of slope and areas between the fistula and non-fistula arms were observed in the Arteria radialis, A. brachialis and arterialized Vena cephalica. The sum of the slope differences was found to correlate with an increased flow, while in patients with fistula failure no changes in PW morphology were seen. Moreover, PWV was significantly reduced in the fistula arm. CONCLUSION Beside duplex sonography, ambilateral peripheral PWA and PWV measurements are potential new clinical applications to characterize and monitor RCF function, especially in terms of high and low flow.
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Affiliation(s)
- Niklas Mueller
- Department of Internal Medicine D, Division of General Internal Medicine, Nephrology and Rheumatology, University Hospital Münster, Münster, Germany.,Department of Internal Medicine III, Division of Haematology and Oncology, Hospital of the Ludwig-Maximilians University Munich, Munich, Germany
| | - Joachim Streis
- Research Center for BioMedical Technology, University of Applied Sciences and Arts, Dortmund, Germany
| | - Sandra Müller
- Kurt Gödel Research Center, Faculty of Mathematics, University of Vienna, Vienna, Austria
| | - Hermann Pavenstädt
- Department of Internal Medicine D, Division of General Internal Medicine, Nephrology and Rheumatology, University Hospital Münster, Münster, Germany
| | - Thomas Felderhoff
- Research Center for BioMedical Technology, University of Applied Sciences and Arts, Dortmund, Germany
| | - Stefan Reuter
- Department of Internal Medicine D, Division of General Internal Medicine, Nephrology and Rheumatology, University Hospital Münster, Münster, Germany,
| | - Veit Busch
- Department of Internal Medicine D, Division of General Internal Medicine, Nephrology and Rheumatology, University Hospital Münster, Münster, Germany.,Research Center for BioMedical Technology, University of Applied Sciences and Arts, Dortmund, Germany.,Nephrovital, Kamen, Germany
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40
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Marx L, Gsell MAF, Rund A, Caforio F, Prassl AJ, Toth-Gayor G, Kuehne T, Augustin CM, Plank G. Personalization of electro-mechanical models of the pressure-overloaded left ventricle: fitting of Windkessel-type afterload models. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190342. [PMID: 32448067 PMCID: PMC7287328 DOI: 10.1098/rsta.2019.0342] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/01/2020] [Indexed: 05/21/2023]
Abstract
Computer models of left ventricular (LV) electro-mechanics (EM) show promise as a tool for assessing the impact of increased afterload upon LV performance. However, the identification of unique afterload model parameters and the personalization of EM LV models remains challenging due to significant clinical input uncertainties. Here, we personalized a virtual cohort of N = 17 EM LV models under pressure overload conditions. A global-local optimizer was developed to uniquely identify parameters of a three-element Windkessel (Wk3) afterload model. The sensitivity of Wk3 parameters to input uncertainty and of the EM LV model to Wk3 parameter uncertainty was analysed. The optimizer uniquely identified Wk3 parameters, and outputs of the personalized EM LV models showed close agreement with clinical data in all cases. Sensitivity analysis revealed a strong dependence of Wk3 parameters on input uncertainty. However, this had limited impact on outputs of EM LV models. A unique identification of Wk3 parameters from clinical data appears feasible, but it is sensitive to input uncertainty, thus depending on accurate invasive measurements. By contrast, the EM LV model outputs were less sensitive, with errors of less than 8.14% for input data errors of 10%, which is within the bounds of clinical data uncertainty. This article is part of the theme issue 'Uncertainty quantification in cardiac and cardiovascular modelling and simulation'.
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Affiliation(s)
- Laura Marx
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University Graz, Graz, Austria
| | - Matthias A. F. Gsell
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University Graz, Graz, Austria
| | - Armin Rund
- Institute for Mathematics and Scientific Computing, University of Graz, Graz, Austria
| | - Federica Caforio
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University Graz, Graz, Austria
| | - Anton J. Prassl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University Graz, Graz, Austria
| | - Gabor Toth-Gayor
- Department of Cardiology, Medical University Graz, Graz, Austria
| | - Titus Kuehne
- Institute for Cardiovascular Computer-assisted Medicine (ICM), Charité - Universitätsmedizin Berlin, Berlin, Germany
- Department of Imaging and Congenital Heart Disease, German Heart Center Berlin, Berlin, Germany
| | - Christoph M. Augustin
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University Graz, Graz, Austria
| | - Gernot Plank
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University Graz, Graz, Austria
- e-mail:
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41
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Hughes AD, Park C, Ramakrishnan A, Mayet J, Chaturvedi N, Parker KH. Feasibility of Estimation of Aortic Wave Intensity Using Non-invasive Pressure Recordings in the Absence of Flow Velocity in Man. Front Physiol 2020; 11:550. [PMID: 32528317 PMCID: PMC7260344 DOI: 10.3389/fphys.2020.00550] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/30/2020] [Indexed: 01/09/2023] Open
Abstract
Background Wave intensity analysis provides valuable information on ventriculo-arterial function, hemodynamics, and energy transfer in the arterial circulation. Widespread use of wave intensity analysis is limited by the need for concurrent measurement of pressure and flow waveforms. We describe a method that can estimate wave intensity patterns using only non-invasive pressure waveforms (pWIA). Methods Radial artery pressure and left ventricular outflow tract (LVOT) flow velocity waveforms were recorded in 12 participants in the Southall and Brent Revisited (SABRE) study. Pressure waveforms were analyzed using custom-written software to derive the excess pressure (Pxs) which was scaled to peak LVOT velocity and used to calculate wave intensity. These data were compared with wave intensity calculated using the measured LVOT flow velocity waveform. In a separate study, repeat measures of pWIA were performed on 34 individuals who attended two clinic visits at an interval of ≈1 month to assess reproducibility and reliability of the method. Results Pxs waveforms were similar in shape to aortic flow velocity waveforms and the time of peak Pxs and peak aortic velocity agreed closely. Wave intensity estimated using pWIA showed acceptable agreement with estimates using LVOT velocity tracings and estimates of wave intensity were similar to values reported previously in the literature. The method showed fair to good reproducibility for most parameters. Conclusion The Pxs is a surrogate of LVOT flow velocity which, when appropriately scaled, allows estimation of aortic wave intensity with acceptable reproducibility. This may enable wider application of wave intensity analysis to large studies.
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Affiliation(s)
- Alun D Hughes
- Medical Research Council Unit for Lifelong Health and Ageing at UCL, Department of Population Science & Experimental Medicine, Faculty of Population Health Sciences, Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Chloe Park
- Medical Research Council Unit for Lifelong Health and Ageing at UCL, Department of Population Science & Experimental Medicine, Faculty of Population Health Sciences, Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Anenta Ramakrishnan
- Cardiovascular Division, Faculty of Medicine, Imperial College London, National Heart & Lung Institute, London, United Kingdom.,Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Jamil Mayet
- Cardiovascular Division, Faculty of Medicine, Imperial College London, National Heart & Lung Institute, London, United Kingdom
| | - Nish Chaturvedi
- Medical Research Council Unit for Lifelong Health and Ageing at UCL, Department of Population Science & Experimental Medicine, Faculty of Population Health Sciences, Institute of Cardiovascular Science, University College London, London, United Kingdom
| | - Kim H Parker
- Department of Bioengineering, Imperial College London, London, United Kingdom
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42
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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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43
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Michail M, Hughes AD, Comella A, Cameron JN, Gooley RP, McCormick LM, Mathur A, Parker KH, Brown AJ, Cameron JD. Acute Effects of Transcatheter Aortic Valve Replacement on Central Aortic Hemodynamics in Patients With Severe Aortic Stenosis. Hypertension 2020; 75:1557-1564. [PMID: 32306768 DOI: 10.1161/hypertensionaha.119.14385] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Severe aortic stenosis induces abnormalities in central aortic pressure, with consequent impaired organ and tissue perfusion. Relief of aortic stenosis by transcatheter aortic valve replacement (TAVR) is associated with both a short- and long-term hypertensive response. Counterintuitively, patients who are long-term normotensive post-TAVR have a worsened prognosis compared with patients with hypertension, yet the underlying mechanisms are not understood. We investigated immediate changes in invasively measured left ventricular and central aortic pressure post-TAVR in patients with severe aortic stenosis using aortic reservoir pressure, wave intensity analysis, and indices of aortic function. Fifty-four patients (mean age 83.6±6.2 years, 50.0% female) undergoing TAVR were included. We performed reservoir pressure and wave intensity analysis on invasively acquired pressure waveforms from the ascending aorta and left ventricle immediately pre- and post-TAVR. Following TAVR, there were increases in systolic, diastolic, mean, and pulse aortic pressures (all P<0.05). Post-TAVR reservoir pressure was unchanged (54.5±12.4 versus 56.6±14.0 mm Hg, P=0.30) whereas excess pressure increased 47% (29.0±10.9 versus 42.6±15.5 mm Hg, P<0.001). Wave intensity analysis (arbitrary units, au) demonstrated increased forward compression wave (64.9±35.5 versus 124.4±58.9, ×103 au, P<0.001), backward compression wave (11.6±5.5 versus 14.4±6.9, ×103 au, P=0.01) and forward expansion wave energies (43.2±27.3 versus 82.8±53.1, ×103 au, P<0.001). Subendocardial viability ratio improved with aortic function effectively unchanged post-TAVR. Increased central aortic pressure following TAVR relates to increased transmitted power and energy to the proximal aorta with increased excess pressure but unchanged reservoir pressure. These changes provide a potential mechanism for the improved prognosis associated with relative hypertension post-TAVR.
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Affiliation(s)
- Michael Michail
- From the Monash Cardiovascular Research Centre and MonashHeart, Monash University and Monash Health, Melbourne, Australia (M.M., A.C., R.G., L.M.M., A.J.B., J.D.C.).,Institute of Cardiovascular Science, University College London, United Kingdom (M.M., A.D.H., A.M.)
| | - Alun D Hughes
- Institute of Cardiovascular Science, University College London, United Kingdom (M.M., A.D.H., A.M.)
| | - Andrea Comella
- From the Monash Cardiovascular Research Centre and MonashHeart, Monash University and Monash Health, Melbourne, Australia (M.M., A.C., R.G., L.M.M., A.J.B., J.D.C.)
| | - James N Cameron
- St George's Hospital Medical School, London, United Kingdom (J.N.C.)
| | - Robert P Gooley
- From the Monash Cardiovascular Research Centre and MonashHeart, Monash University and Monash Health, Melbourne, Australia (M.M., A.C., R.G., L.M.M., A.J.B., J.D.C.)
| | - Liam M McCormick
- From the Monash Cardiovascular Research Centre and MonashHeart, Monash University and Monash Health, Melbourne, Australia (M.M., A.C., R.G., L.M.M., A.J.B., J.D.C.)
| | - Anthony Mathur
- Institute of Cardiovascular Science, University College London, United Kingdom (M.M., A.D.H., A.M.).,Centre for Cardiovascular Medicine and Device Innovation, Queen Mary University of London, United Kingdom (A.M.)
| | - Kim H Parker
- Department of Bioengineering, Imperial College, London, United Kingdom (K.M.P.)
| | - Adam J Brown
- From the Monash Cardiovascular Research Centre and MonashHeart, Monash University and Monash Health, Melbourne, Australia (M.M., A.C., R.G., L.M.M., A.J.B., J.D.C.)
| | - James D Cameron
- From the Monash Cardiovascular Research Centre and MonashHeart, Monash University and Monash Health, Melbourne, Australia (M.M., A.C., R.G., L.M.M., A.J.B., J.D.C.)
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Quantification of Pulsed Operation of Rotary Left Ventricular Assist Devices with Wave Intensity Analysis. ASAIO J 2020; 65:324-330. [PMID: 29863632 DOI: 10.1097/mat.0000000000000821] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The current generation of left ventricular assist devices (LVADs) provides continuous flow and has the capacity to reduce aortic pulsatility, which may be related to a range of complications associated with these devices. Pulsed LVAD operation using speed modulation presents a mechanism to restore aortic pulsatility and potentially mitigate complications. We sought to investigate the interaction of axial and centrifugal LVADs with the LV and quantify the effects of continuous and pulsed LVAD operations on LV generated wave patterns under different physiologic conditions using wave intensity analysis (WIA) method. The axial LVAD created greater wave intensity associated with LV relaxation. In both LVADs, there were only minor and variable differences between the continuous and pulsed operations. The response to physiologic stress was preserved with LVAD implantation as wave intensity increased marginally with volume loading and significantly with infusion of norepinephrine. Our findings and a new approach of investigating aortic wave patterns based on WIA are expected to provide useful clinical insights to determine the ideal operation of LVADs.
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45
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Armstrong MK, Schultz MG, Picone DS, Black JA, Dwyer N, Roberts-Thomson P, Sharman JE. Associations of Reservoir-Excess Pressure Parameters Derived From Central and Peripheral Arteries With Kidney Function. Am J Hypertens 2020; 33:325-330. [PMID: 32006010 DOI: 10.1093/ajh/hpaa013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 12/17/2019] [Accepted: 01/30/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Central artery reservoir-excess pressure parameters are clinically important but impractical to record directly. However, diastolic waveform morphology is consistent across central and peripheral arteries. Therefore, peripheral artery reservoir-excess pressure parameters related to diastolic waveform morphology may be representative of central parameters and share clinically important associations with end-organ damage. This has never been determined and was the aim of this study. METHODS Intra-arterial blood pressure (BP) waveforms were measured sequentially at the aorta, brachial, and radial arteries among 220 individuals (aged 61 ± 10 years, 68% male). Customized software was used to derive reservoir-excess pressure parameters at each arterial site (reservoir and excess pressure, systolic and diastolic rate constants) and clinical relevance was determined by association with estimated glomerular filtration rate (eGFR). RESULTS Between the aorta and brachial artery, the mean difference in the diastolic rate constant and reservoir pressure integral was -0.162 S-1 (P = 0.08) and -0.772 mm Hg s (P = 0.23), respectively. The diastolic rate constant had the strongest and most consistent associations with eGFR across aortic and brachial sites (β = -0.20, P = 0.02; β = -0.20, P = 0.03, respectively; adjusted for traditional cardiovascular risk factors). Aortic, but not brachial peak reservoir pressure was associated with eGFR in adjusted models (aortic β = -0.48, P = 0.02). CONCLUSIONS The diastolic rate constant is the most consistent reservoir-excess pressure parameter, in both its absolute values and associations with kidney dysfunction, when derived from the aorta and brachial artery. Thus, the diastolic rate constant could be utilized in the clinical setting to improve BP risk stratification.
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Affiliation(s)
| | - Martin G Schultz
- Menzies Institute for Medical Research, University of Tasmania, Australia
| | - Dean S Picone
- Menzies Institute for Medical Research, University of Tasmania, Australia
| | - J Andrew Black
- Department of Cardiology, Royal Hobart Hospital, 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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Association of brachial-cuff excess pressure with carotid intima-media thickness in Australian adults: a cross-sectional study. J Hypertens 2020; 38:723-730. [PMID: 32134846 DOI: 10.1097/hjh.0000000000002310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Reservoir pressure parameters [e.g. reservoir pressure (RP) and excess pressure (XSP)] measured using tonometry predict cardiovascular events beyond conventional risk factors. However, the operator dependency of tonometry impedes widespread use. An operator-independent cuff-based device can reasonably estimate the intra-aortic RP and XSP from brachial volumetric waveforms, but whether these estimates are clinically relevant to preclinical phenotypes of cardiovascular risk has not been investigated. METHODS The RP and XSP were derived from brachial volumetric waveforms measured using cuff oscillometry (SphygmoCor XCEL) in 1691 mid-life adults from the CheckPoint study (a population-based cross-sectional study nested in the Longitudinal Study of Australian Children). Carotid intima--media thickness (carotid IMT, n = 1447) and carotid--femoral pulse wave velocity (PWV, n = 1632) were measured as preclinical phenotypes of cardiovascular risk. Confounders were conventional risk factors that were correlated with both exposures and outcomes or considered as physiologically important. RESULTS There was a modest association between XSP and carotid IMT (β = 0.76 μm, 95% CI, 0.25-1.26 partial R = 0.8%) after adjusting for age, sex, BMI, heart rate, smoking, diabetes, high-density lipoprotein cholesterol and mean arterial pressure. Neither RP nor XSP were associated with PWV in the similarly adjusted models (β = -0.47 cm/s, 95% CI, -1.15 to 0.20, partial R = 0.2% for RP, and β = 0.04 cm/s, 95% CI, -0.59 to 0.67, partial R = 0.01% for XSP). CONCLUSION Cuff-based XSP associates with carotid IMT independent of conventional risk factors, including traditional BP, but the association was weak, indicating that further investigation is warranted to understand the clinical significance of reservoir pressure parameters.
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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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Paré M, Goupil R, Fortier C, Mac-Way F, Madore F, Marquis K, Hametner B, Wassertheurer S, Schultz MG, Sharman JE, Agharazii M. Determinants of Increased Central Excess Pressure in Dialysis: Role of Dialysis Modality and Arteriovenous Fistula. Am J Hypertens 2020; 33:137-145. [PMID: 31419806 DOI: 10.1093/ajh/hpz136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/31/2019] [Accepted: 08/12/2019] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Arterial reservoir-wave analysis (RWA)-a new model of arterial hemodynamics-separates arterial wave into reservoir pressure (RP) and excess pressure (XSP). The XSP integral (XSPI) has been associated with increased risk of clinical outcomes. The objectives of the present study were to examine the determinants of XSPI in a mixed cohort of hemodialysis (HD) and peritoneal dialysis (PD) patients, to examine whether dialysis modality and the presence of an arteriovenous fistula (AVF) are associated with increased XSPI. METHOD In a cross-sectional study, 290 subjects (232 HD and 130 with AVF) underwent carotid artery tonometry (calibrated with brachial diastolic and mean blood pressure). The XSPI was calculated through RWA using pressure-only algorithms. Logistic regression was used for determinants of XSPI above median. Through forward conditional linear regression, we examined whether treatment by HD or the presence of AVF is associated with higher XSPI. RESULTS Patients with XSPI above median were older, had a higher prevalence of diabetes and cardiovascular disease, had a higher body mass index, and were more likely to be on HD. After adjustment for confounders, HD was associated with a higher risk of higher XSPI (odds ratio = 2.39, 95% confidence interval: 1.16-4.98). In a forward conditional linear regression analysis, HD was associated with higher XSPI (standardized coefficient: 0.126, P = 0.012), but on incorporation of AVF into the model, AVF was associated with higher XSPI (standardized coefficient: 0.130, P = 0.008) and HD was excluded as a predictor. CONCLUSION This study suggests that higher XSPI in HD patients is related to the presence of AVF.
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Affiliation(s)
- Mathilde Paré
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Québec, Quebec, Canada
- Division of Nephrology, Faculty of Medicine, Université Laval, Québec, Quebec, Canada
| | - Rémi Goupil
- Hôpital du Sacré-Cœur de Montréal, Montréal, Quebec, Canada
| | - Catherine Fortier
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Québec, Quebec, Canada
- Division of Nephrology, Faculty of Medicine, Université Laval, Québec, Quebec, Canada
| | - Fabrice Mac-Way
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Québec, Quebec, Canada
- Division of Nephrology, Faculty of Medicine, Université Laval, Québec, Quebec, Canada
| | | | - Karine Marquis
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Québec, Quebec, Canada
| | - Bernhard Hametner
- Center for Health and Bioresources, AIT Austrian Institute of Technology, Vienna, Austria
| | | | - Martin G Schultz
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - James E Sharman
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Mohsen Agharazii
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Québec, Quebec, Canada
- Division of Nephrology, Faculty of Medicine, Université Laval, Québec, Quebec, Canada
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Man AWC, Li H, Xia N. Resveratrol and the Interaction between Gut Microbiota and Arterial Remodelling. Nutrients 2020; 12:nu12010119. [PMID: 31906281 PMCID: PMC7019510 DOI: 10.3390/nu12010119] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 12/23/2019] [Accepted: 12/25/2019] [Indexed: 12/15/2022] Open
Abstract
Arterial remodelling refers to the alteration in the structure of blood vessel that contributes to the progression of hypertension and other cardiovascular complications. Arterial remodelling is orchestrated by the crosstalk between the endothelium and vascular smooth muscle cells (VSMC). Vascular inflammation participates in arterial remodelling. Resveratrol is a natural polyphenol that possesses anti-oxidant and anti-inflammatory properties and has beneficial effects in both the endothelium and VSMC. Resveratrol has been studied for the protective effects in arterial remodelling and gut microbiota, respectively. Gut microbiota plays a critical role in the immune system and inflammatory processes. Gut microbiota may also regulate vascular remodelling in cardiovascular complications via affecting endothelium function and VSMC proliferation. Currently, there is new evidence showing that gut microbiota regulate the proliferation of VSMC and the formation of neointimal hyperplasia in response to injury. The change in population of the gut microbiota, as well as their metabolites (e.g., short-chain fatty acids) could critically contribute to VSMC proliferation, cell cycle progression, and migration. Recent studies have provided strong evidence that correlate the effects of resveratrol in arterial remodelling and gut microbiota. This review aims to summarize recent findings on the resveratrol effects on cardiovascular complications focusing on arterial remodelling and discuss the possible interactions of resveratrol and the gut microbiota that modulate arterial remodelling.
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Affiliation(s)
- Andy W C Man
- Department of Pharmacology, Johannes Gutenberg University Medical Center, 55131 Mainz, Germany
| | - Huige Li
- Department of Pharmacology, Johannes Gutenberg University Medical Center, 55131 Mainz, Germany
| | - Ning Xia
- Department of Pharmacology, Johannes Gutenberg University Medical Center, 55131 Mainz, Germany
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Changes in hemodynamics associated with metabolic syndrome are more pronounced in women than in men. Sci Rep 2019; 9:18377. [PMID: 31804574 PMCID: PMC6895092 DOI: 10.1038/s41598-019-54926-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 11/18/2019] [Indexed: 01/09/2023] Open
Abstract
The increase in cardiovascular risk associated with metabolic syndrome (MS) seems higher in women than in men. We examined hemodynamics during head-up tilt in 252 men and 250 women without atherosclerosis, diabetes, or antihypertensive medication, mean age 48 years, using whole-body impedance cardiography and radial pulse wave analysis. MS was defined according to Alberti et al. 2009. Men and women with MS presented with corresponding elevations of systolic and diastolic blood pressure (10-14%, p ≤ 0.001) versus controls. Supine pulse wave velocity (16-17%, p < 0.001) and systemic vascular resistance (7-9%, p ≤ 0.026), and upright cardiac output (6-11%, p ≤ 0.008) were higher in both MS groups than controls. Elevation of supine aortic characteristic impedance was higher in women than in men with MS (16% vs. 8%, p = 0.026), and in contrast to men, no upright impedance reduction was observed in women. When upright, women but not men with MS showed faster return of reflected pressure wave (p = 0.036), and smaller decrease in left cardiac work (p = 0.035) versus controls. The faster upright return of reflected pressure, lower upright decrease in left cardiac work, and higher elevation of aortic characteristic impedance may contribute to the greater increase in MS-related cardiovascular risk in women than in men.
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