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Zieff G, Stone K, Paterson C, Fryer S, Diana J, Blackwell J, Meyer ML, Stoner L. Pulse-wave velocity assessments derived from a simple photoplethysmography device: Agreement with a referent device. Front Cardiovasc Med 2023; 10:1108219. [PMID: 36824455 PMCID: PMC9941627 DOI: 10.3389/fcvm.2023.1108219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 01/23/2023] [Indexed: 02/10/2023] Open
Abstract
Objective Pulse-wave velocity (PWV), a common measure of arterial stiffness, can be measured continuously and across multiple body sites using photoplethysmography (PPG). The objective was to determine whether a simple photoplethysmography PPG PWV method agrees with a referent device. Approach Photoplethysmography heart-finger PWV (hfPWV) and heart-toe PWV (htPWV) were compared to oscillometric carotid-wrist PWV (cwPWV) and carotid-ankle PWV (caPWV) referent measurements, respectively. In 30 adults (24.6 ± 4.8 years, body mass index 25.2 ± 5.9 kg/m2, 18 female), three measurements were made: two supine baseline measurements (Base 1, Base 2) and one measurement (Tilt) 5 min after a modified head-up tilt test (mHUTT). Overall agreement and repeated measures agreement (change in PPG PWV from Base to Tilt vs. change in referent PWV from Base to Tilt) were calculated using linear mixed models. Agreement estimates were expressed as intra-class correlation coefficients (ICC). Main results For hfPWV there was strong overall agreement (ICC: 0.77, 95%CI: 0.67-0.85), but negligible and non-significant repeated measures agreement (ICC: 0.10, 95%CI: -0.18 to 0.36). For htPWV, there was moderate overall agreement (ICC:0.50, 95%CI: 0.31-0.65) and strong repeated measures agreement (ICC: 0.81, 95%CI: 0.69-0.89). Significance Photoplethysmography can continuously measure PWV at multiple arterial segments with moderate-strong overall agreement. While further work with upper-limb PPG PWV is needed, PPG can adequately capture acute changes in lower-limb PWV.
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Affiliation(s)
- Gabriel Zieff
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States,*Correspondence: Gabriel Zieff,
| | - Keeron Stone
- School of Sport and Exercise, University of Gloucestershire, Gloucester, United Kingdom
| | - Craig Paterson
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States,School of Sport and Exercise, University of Gloucestershire, Gloucester, United Kingdom
| | - Simon Fryer
- School of Sport and Exercise, University of Gloucestershire, Gloucester, United Kingdom
| | - Jake Diana
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jade Blackwell
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States,Department of Physiology, The University of Arizona, Tucson, AZ, United States
| | - Michelle L. Meyer
- Department of Emergency Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Lee Stoner
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Pilotto AM, Adami A, Mazzolari R, Brocca L, Crea E, Zuccarelli L, Pellegrino MA, Bottinelli R, Grassi B, Rossiter HB, Porcelli S. Near-infrared spectroscopy estimation of combined skeletal muscle oxidative capacity and O 2 diffusion capacity in humans. J Physiol 2022; 600:4153-4168. [PMID: 35930524 PMCID: PMC9481735 DOI: 10.1113/jp283267] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 07/27/2022] [Indexed: 01/05/2023] Open
Abstract
The final steps of the O2 cascade during exercise depend on the product of the microvascular-to-intramyocyteP O 2 ${P}_{{{\rm{O}}}_{\rm{2}}}$ difference and muscle O2 diffusing capacity (D m O 2 $D{{\rm{m}}}_{{{\rm{O}}}_2}$ ). Non-invasive methods to determineD m O 2 $D{{\rm{m}}}_{{{\rm{O}}}_2}$ in humans are currently unavailable. Muscle oxygen uptake (mV ̇ O 2 ${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ ) recovery rate constant (k), measured by near-infrared spectroscopy (NIRS) using intermittent arterial occlusions, is associated with muscle oxidative capacity in vivo. We reasoned that k would be limited byD m O 2 $D{{\rm{m}}}_{{{\rm{O}}}_2}$ when muscle oxygenation is low (kLOW ), and hypothesized that: (i) k in well oxygenated muscle (kHIGH ) is associated with maximal O2 flux in fibre bundles; and (ii) ∆k (kHIGH - kLOW ) is associated with capillary density (CD). Vastus lateralis k was measured in 12 participants using NIRS after moderate exercise. The timing and duration of arterial occlusions were manipulated to maintain tissue saturation index within a 10% range either below (LOW) or above (HIGH) half-maximal desaturation, assessed during sustained arterial occlusion. Maximal O2 flux in phosphorylating state was 37.7 ± 10.6 pmol s-1 mg-1 (∼5.8 ml min-1 100 g-1 ). CD ranged 348 to 586 mm-2 . kHIGH was greater than kLOW (3.15 ± 0.45 vs. 1.56 ± 0.79 min-1 , P < 0.001). Maximal O2 flux was correlated with kHIGH (r = 0.80, P = 0.002) but not kLOW (r = -0.10, P = 0.755). Δk ranged -0.26 to -2.55 min-1 , and correlated with CD (r = -0.68, P = 0.015). mV ̇ O 2 ${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ k reflects muscle oxidative capacity only in well oxygenated muscle. ∆k, the difference in k between well and poorly oxygenated muscle, was associated with CD, a mediator ofD m O 2 $D{{\rm{m}}}_{{{\rm{O}}}_2}$ . Assessment of muscle k and ∆k using NIRS provides a non-invasive window on muscle oxidative and O2 diffusing capacity. KEY POINTS: We determined post-exercise recovery kinetics of quadriceps muscle oxygen uptake (mV ̇ O 2 ${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ ) measured by near-infrared spectroscopy (NIRS) in humans under conditions of both non-limiting (HIGH) and limiting (LOW) O2 availability, for comparison with biopsy variables. The mV ̇ O 2 ${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ recovery rate constant in HIGH O2 availability was hypothesized to reflect muscle oxidative capacity (kHIGH ) and the difference in k between HIGH and LOW O2 availability (∆k) was hypothesized to reflect muscle O2 diffusing capacity. kHIGH was correlated with phosphorylating oxidative capacity of permeabilized muscle fibre bundles (r = 0.80). ∆k was negatively correlated with capillary density (r = -0.68) of biopsy samples. NIRS provides non-invasive means of assessing both muscle oxidative and oxygen diffusing capacity in vivo.
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Affiliation(s)
- Andrea M. Pilotto
- Department of MedicineUniversity of UdineUdineItaly
- Department of Molecular MedicineInstitute of PhysiologyUniversity of PaviaPaviaItaly
| | - Alessandra Adami
- Department of KinesiologyUniversity of Rhode IslandKingstonRIUSA
| | - Raffaele Mazzolari
- Department of Molecular MedicineInstitute of PhysiologyUniversity of PaviaPaviaItaly
- Department of Physical Education and SportUniversity of the Basque Country (UPV/EHU)Vitoria‐GasteizSpain
| | - Lorenza Brocca
- Department of Molecular MedicineInstitute of PhysiologyUniversity of PaviaPaviaItaly
| | - Emanuela Crea
- Department of Molecular MedicineInstitute of PhysiologyUniversity of PaviaPaviaItaly
| | | | - Maria A. Pellegrino
- Department of Molecular MedicineInstitute of PhysiologyUniversity of PaviaPaviaItaly
- Interdipartimental Centre for Biology and Sport MedicineUniversity of PaviaPaviaItaly
| | - Roberto Bottinelli
- Department of Molecular MedicineInstitute of PhysiologyUniversity of PaviaPaviaItaly
- Interdipartimental Centre for Biology and Sport MedicineUniversity of PaviaPaviaItaly
| | - Bruno Grassi
- Department of MedicineUniversity of UdineUdineItaly
| | - Harry B. Rossiter
- Division of Respiratory and Critical Care Physiology and MedicineThe Lundquist Institute for Biomedical Innovation at Harbor–UCLA Medical CenterTorranceCAUSA
| | - Simone Porcelli
- Department of Molecular MedicineInstitute of PhysiologyUniversity of PaviaPaviaItaly
- Institute of Biomedical TechnologiesNational Research CouncilMilanItaly
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Jain P, Bellettiere J, Glass N, LaMonte MJ, Di C, Wild RA, Evenson KR, LaCroix AZ. The Relationship of Accelerometer-Assessed Standing Time With and Without Ambulation and Mortality: The WHI OPACH Study. J Gerontol A Biol Sci Med Sci 2021; 76:77-84. [PMID: 33225345 DOI: 10.1093/gerona/glaa227] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Self-reported time spent standing has been associated with lower risk of mortality. No previous studies have examined this association using device-measured standing. METHOD This was a prospective cohort study of 5878 older (median age = 80 years), racial/ethnically diverse, community-dwelling women in the WHI Objective Physical Activity and Cardiovascular Health Study (OPACH). Women wore accelerometers for 1 week and were followed for mortality. The study applied previously validated machine learning algorithms to ActiGraph GT3X+ accelerometer data to separately measure time spent standing with and without ambulation. Cox proportional hazards models were used to estimate mortality risk adjusting for potential confounders. Effect modification by age, body mass index, moderate-to-vigorous physical activity, sedentary time, physical functioning, and race/ethnicity was evaluated. RESULTS There were 691 deaths during 26 649 person-years of follow-up through March 31, 2018 (mean follow-up = 4.8 years). In fully adjusted models, all-cause mortality risk was lower among those with more standing without ambulation (quartile [Q] 4 vs Q1 HR = 0.63; 95% CI = 0.49-0.81, p-trend = .003) and more standing with ambulation (Q4 vs Q1 HR = 0.50; 95% CI = 0.35-0.71, p-trend < .001). Associations of standing with ambulation and mortality were stronger among women with above-median sedentary time (HR = 0.51; 95% CI = 0.38-0.68) compared to women with below-median sedentary time (HR = 0.80; 95% CI = 0.59-1.07; p-interaction = .02). CONCLUSIONS In this prospective study among older women, higher levels of accelerometer-measured standing were associated with lower risks of all-cause mortality. Standing is an achievable approach to interrupting prolonged sedentary time, and if not contraindicated, is a safe and feasible behavior that appears to benefit health in older ages.
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Affiliation(s)
- Purva Jain
- Department of Family Medicine and Public Health, University of California San Diego, La Jolla
| | - John Bellettiere
- Department of Family Medicine and Public Health, University of California San Diego, La Jolla
| | - Nicole Glass
- Department of Family Medicine and Public Health, University of California San Diego, La Jolla
| | - Michael J LaMonte
- Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo-SUNY, New York
| | - Chongzhi Di
- Fred Hutchinson Cancer Center, Seattle, Washington
| | | | - Kelly R Evenson
- Department of Epidemiology, University of North Carolina, Chapel Hill
| | - Andrea Z LaCroix
- Department of Family Medicine and Public Health, University of California San Diego, La Jolla
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4
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Hartman SJ, Dillon LW, LaCroix AZ, Natarajan L, Sears DD, Owen N, Dunstan DW, Sallis JF, Schenk S, Allison M, Takemoto M, Herweck AM, Nguyen B, Rosenberg DE. Interrupting Sitting Time in Postmenopausal Women: Protocol for the Rise for Health Randomized Controlled Trial. JMIR Res Protoc 2021; 10:e28684. [PMID: 33983131 PMCID: PMC8160808 DOI: 10.2196/28684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 04/04/2021] [Indexed: 11/17/2022] Open
Abstract
Background Many older adults spend the majority of their waking hours sitting, which increases their risk of chronic diseases. Given the challenges that many older adults face when engaging in moderate-to-vigorous physical activity, understanding the health benefits of decreasing sitting time and increasing the number of sit-to-stand transitions is needed to address this growing public health concern. Objective The aim of this 3-arm randomized controlled trial is to investigate how changes in sitting time and brief sit-to-stand transitions impact biomarkers of healthy aging and physical, emotional, and cognitive functioning compared with a healthy attention control arm. Methods Sedentary and postmenopausal women (N=405) will be recruited and randomly assigned to 1 of the 3 study conditions for 3 months: healthy living attention control (Healthy Living), reduce sitting time (Reduce Sitting), and increase sit-to-stand transitions (Increase Transitions). Assessments conducted at baseline and 3 months included fasting blood draw, blood pressure, anthropometric measurements, physical functioning, cognitive testing, and 7 days of a thigh-worn accelerometer (activPAL) and a hip-worn accelerometer (ActiGraph). Blood-based biomarkers of healthy aging included those associated with glycemic control (glycated hemoglobin, fasting plasma insulin and glucose, and homeostatic model assessment of insulin resistance). Results Recruitment began in May 2018. The intervention is ongoing, with data collection expected to continue through the end of 2022. Conclusions The Rise for Health study is designed to test whether 2 different approaches to interrupting sitting time can improve healthy aging in postmenopausal women. Results from this study may inform the development of sedentary behavior guidelines and interventions to reduce sitting time in older adults. Trial Registration ClinicalTrials.gov NCT03473145; https://clinicaltrials.gov/ct2/show/NCT03473145 International Registered Report Identifier (IRRID) DERR1-10.2196/28684
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Affiliation(s)
- Sheri J Hartman
- Hebert Wertheim School of Public Health, University of California, San Diego, La Jolla, CA, United States.,Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States
| | - Lindsay W Dillon
- Hebert Wertheim School of Public Health, University of California, San Diego, La Jolla, CA, United States
| | - Andrea Z LaCroix
- Hebert Wertheim School of Public Health, University of California, San Diego, La Jolla, CA, United States
| | - Loki Natarajan
- Hebert Wertheim School of Public Health, University of California, San Diego, La Jolla, CA, United States
| | - Dorothy D Sears
- Moores Cancer Center, University of California, San Diego, La Jolla, CA, United States.,Department of Medicine, University of California, San Diego, La Jolla, CA, United States.,College of Health Solutions, Arizona State University, Phoenix, AZ, United States.,Department of Family Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Neville Owen
- Baker Heart and Diabetes Institute, Melbourne, Australia.,Centre for Urban Transitions, Swinburne University, Melbourne, Australia
| | - David W Dunstan
- Baker Heart and Diabetes Institute, Melbourne, Australia.,Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
| | - James F Sallis
- Hebert Wertheim School of Public Health, University of California, San Diego, La Jolla, CA, United States
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California, San Diego, La Jolla, CA, United States
| | - Matthew Allison
- Department of Family Medicine, University of California, San Diego, La Jolla, CA, United States
| | | | - Alexandra M Herweck
- Hebert Wertheim School of Public Health, University of California, San Diego, La Jolla, CA, United States
| | - Bao Nguyen
- School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Dori E Rosenberg
- Kaiser Permanente Washington Health Research Institute, Seattle, WA, United States
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5
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Reliability of pulse waveform separation analysis responses to an orthostatic challenge. Hypertens Res 2018; 41:176-182. [PMID: 29335614 DOI: 10.1038/s41440-017-0005-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 07/17/2017] [Accepted: 08/04/2017] [Indexed: 11/08/2022]
Abstract
Cardiovascular autonomic nervous system function can be assessed using an orthostatic challenge to induce arterial wave reflection. While arterial reflection is typically estimated using a central augmentation index, a superior estimation can be obtained using pulse wave separation analysis to estimate the aortic backward pressure wave (Pb). However, to be of value in a clinical or research setting, an assessment tool must be precise (reliable). Therefore, this study sought to determine the measurement precision of Pb responses to a modified tilt-table test. Twenty healthy adults (26.4 year (SD 5.2), 24.7 kg/m2 (SD 3.8), 55% female) were tested in a fasted state on three different mornings separated by a maximum of seven days. Pressure waveforms were recorded on the left arm, and aortic waveforms were generated using a generalized transfer function. Subsequently, a physiologic flow waveform was assumed to separate the aortic pressure wave into its forward and timing-independent backward (Pb) components. The criterion intra-class correlation coefficient of ≥0.75 was exceeded at baseline (0.79), following a 5-min tilt (0.75), and following a 5-min recovery from tilt (0.75). The standard error of measurement was 7%. These findings indicate that in a healthy cohort, the Pb response to an orthostatic challenge can be assessed with acceptable precision. The next step is to determine the sensitivity (validity) of this technique in identifying cardiovascular autonomic dysfunction in patient groups.
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Kerr J, Crist K, Vital DG, Dillon L, Aden SA, Trivedi M, Castellanos LR, Godbole S, Li H, Allison MA, Khemlina GL, Takemoto ML, Schenk S, Sallis JF, Grace M, Dunstan DW, Natarajan L, LaCroix AZ, Sears DD. Acute glucoregulatory and vascular outcomes of three strategies for interrupting prolonged sitting time in postmenopausal women: A pilot, laboratory-based, randomized, controlled, 4-condition, 4-period crossover trial. PLoS One 2017; 12:e0188544. [PMID: 29190761 PMCID: PMC5708739 DOI: 10.1371/journal.pone.0188544] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 10/12/2017] [Indexed: 11/30/2022] Open
Abstract
Background Prolonged sitting is associated with cardiometabolic and vascular disease. Despite emerging evidence regarding the acute health benefits of interrupting prolonged sitting time, the effectiveness of different modalities in older adults (who sit the most) is unclear. Methods In preparation for a future randomized controlled trial, we enrolled 10 sedentary, overweight or obese, postmenopausal women (mean age 66 years ±9; mean body mass index 30.6 kg/m2 ±4.2) in a 4-condition, 4-period crossover feasibility pilot study in San Diego to test 3 different sitting interruption modalities designed to improve glucoregulatory and vascular outcomes compared to a prolonged sitting control condition. The interruption modalities included: a) 2 minutes standing every 20 minutes; b) 2 minutes walking every hour; and c) 10 minutes standing every hour. During each 5-hr condition, participants consumed two identical, standardized meals. Blood samples, blood pressure, and heart rate were collected every 30 minutes. Endothelial function of the superficial femoral artery was measured at baseline and end of each 5-hr condition using flow-mediated dilation (FMD). Participants completed each condition on separate days, in randomized order. This feasibility pilot study was not powered to detect statistically significant differences in the various outcomes, however, analytic methods (mixed models) were used to test statistical significance within the small sample size. Results Nine participants completed all 4 study visits, one participant completed 3 study visits and then was lost to follow up. Net incremental area under the curve (iAUC) values for postprandial plasma glucose and insulin during the 5-hr sitting interruption conditions were not significantly different compared to the control condition. Exploratory analyses revealed that the 2-minute standing every 20 minutes and the 2-minute walking every hour conditions were associated with a significantly lower glycemic response to the second meal compared to the first meal (i.e., condition-matched 2-hour post-lunch glucose iAUC was lower than 2-hour post-breakfast glucose iAUC) that withstood Bonferroni correction (p = 0.0024 and p = 0.0084, respectively). Using allometrically scaled data, the 10-minute standing every hour condition resulted in an improved FMD response, which was significantly greater than the control condition after Bonferroni correction (p = 0.0033). Conclusion This study suggests that brief interruptions in prolonged sitting time have modality-specific glucoregulatory and vascular benefits and are feasible in an older adult population. Larger laboratory and real-world intervention studies of pragmatic and effective methods to change sitting habits are needed. Trial registration ClinicalTrials.gov NCT02743286.
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Affiliation(s)
- Jacqueline Kerr
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Katie Crist
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Daniela G. Vital
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Lindsay Dillon
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Sabrina A. Aden
- San Diego State University, San Diego, California, United States of America
| | - Minaxi Trivedi
- Center for Clinical Research, Clinical and Translational Research Institute, UC San Diego, La Jolla, California, United States of America
| | - Luis R. Castellanos
- Department of Medicine, UC San Diego, La Jolla, California, United States of America
| | - Suneeta Godbole
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Hongying Li
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Matthew A. Allison
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Galina L. Khemlina
- Department of Medicine, UC San Diego, La Jolla, California, United States of America
| | - Michelle L. Takemoto
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Simon Schenk
- Department of Orthopedic Surgery, UC San Diego, La Jolla, California, United States of America
| | - James F. Sallis
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Megan Grace
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - David W. Dunstan
- Baker IDI Heart and Diabetes Institute, Melbourne, Australia
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Australia
| | - Loki Natarajan
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Andrea Z. LaCroix
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
| | - Dorothy D. Sears
- Department of Family Medicine and Public Health, UC San Diego, La Jolla, California, United States of America
- Department of Medicine, UC San Diego, La Jolla, California, United States of America
- * E-mail:
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Godefroy J, Noblet V, Wolff V, Lauer V, Rouyer O, Marescaux C, Dromson G, Namer IJ. Scintigraphie de perfusion cérébrale positionnelle : résultats physiologiques et applications cliniques. MEDECINE NUCLEAIRE-IMAGERIE FONCTIONNELLE ET METABOLIQUE 2014. [DOI: 10.1016/j.mednuc.2014.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Effect of postural changes on normal and stenosed common carotid artery using FSI. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2014; 37:139-52. [PMID: 24519000 DOI: 10.1007/s13246-014-0246-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
Abstract
Gravity associated with postural changes has a strong bearing on haemodynamics of blood flow in arteries. Its effect on stenosed cases has not been widely investigated. In the present study, variation observed in blood flow during postural changes is investigated for different conditions like standing, sleeping and head-down position. A fluid structure interaction study is carried out for idealized normal and 75% eccentric and concentric stenosed common carotid normal artery. The results clearly indicate the effects of altered gravity on flow conditions. It was found to be very significant during head-down position and demonstrated very high arterial blood pressure in stenosed common carotid when compared with normal carotid.
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Kooijman M, Poelkens F, Rongen GA, Smits P, Hopman MT. Leg blood flow measurements using venous occlusion plethysmography during head-up tilt. Clin Auton Res 2007; 17:106-11. [PMID: 17345054 PMCID: PMC1914255 DOI: 10.1007/s10286-007-0402-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Accepted: 01/24/2007] [Indexed: 11/25/2022]
Abstract
We tested whether venous occlusion plethysmography (VOP) is an appropriate method to measure calf blood flow (CBF) during head-up tilt (HUT). CBF measured with VOP was compared with superficial femoral artery blood flow as measured by Doppler ultrasound during incremental tilt angles. Measurements of both methods correlated well (r = 0.86). Reproducibility of VOP was fair in supine position and 30° HUT (CV: 11%–15%). This indicates that VOP is an applicable tool to measure leg blood flow during HUT, especially up to 30° HUT.
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Affiliation(s)
- Miriam Kooijman
- Dept. of Physiology, Radboud University Nijmegen Medical Centre, Ïnstitute for Fundamental and Clinical Movement Sciences, PO Box 9101, 6500 HB Nijmegen, The Netherlands
- Rehabilitation Centre, Sint Maartenskliniek, Nijmegen, The Netherlands
| | - Fleur Poelkens
- Dept. of Physiology, Radboud University Nijmegen Medical Centre, Ïnstitute for Fundamental and Clinical Movement Sciences, PO Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Gerard A. Rongen
- Dept. of Pharmacology-Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Paul Smits
- Dept. of Pharmacology-Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Maria T.E. Hopman
- Dept. of Physiology, Radboud University Nijmegen Medical Centre, Ïnstitute for Fundamental and Clinical Movement Sciences, PO Box 9101, 6500 HB Nijmegen, The Netherlands
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