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Mahe G, Liedl DA, McCarter C, Shepherd R, Gloviczki P, McPhail IR, Rooke TW, Wennberg PW. Digital obstructive arterial disease can be detected by laser Doppler measurements with high sensitivity and specificity. J Vasc Surg 2014; 59:1051-1057.e1. [DOI: 10.1016/j.jvs.2013.10.076] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/14/2013] [Accepted: 10/15/2013] [Indexed: 10/25/2022]
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GOMES V, GOMES MB, TIBIRICA E, LESSA MA. Post-operative endothelial dysfunction assessment using laser Doppler perfusion measurement in cardiac surgery patients. Acta Anaesthesiol Scand 2014; 58:468-77. [PMID: 24617621 DOI: 10.1111/aas.12286] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2014] [Indexed: 12/27/2022]
Abstract
BACKGROUND Coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB) is associated with systemic inflammatory response and endothelial dysfunction. Our hypothesis is that CPB-induced post-operative endothelial dysfunction may be detected using laser Doppler perfusion monitoring (LDPM) in the skin microcirculation. METHODS We used LDPM to investigate the subacute effects of the CPB on systemic microvascular reactivity among patients undergoing CABG surgery with CPB. Thirty patients were submitted to the study of skin microcirculation and blood sample collection at baseline (pre-surgery) and at 7 days post-surgical procedure. The skin microcirculation was evaluated by acetylcholine (ACh) and sodium nitroprusside (SNP) iontophoresis, and thermal hyperemia (TH). Plasma levels of nitrite/nitrate were also analyzed, and cytokine profiles were determined using a multiplex system. RESULTS On-pump CABG surgery induced a significant reduction of the increased microvascular dermal flux observed after cumulative doses of ACh iontophoresis and after TH. On-pump CABG surgery did not induce any significant changes in the microvascular flux after cumulative doses of SNP. Patients still presented high levels of interleukin (IL)-6, IL-8, and C-reactive protein, and low bioavailability of nitric oxide 7 days after the CABG surgery with CPB. CONCLUSION We observed a significant impairment of systemic microvascular endothelial function and well-preserved endothelium-independent vasodilatation in the skin microcirculation of patients 1 week after CABG surgery with CPB. Our results suggest that LDPM is a useful tool for the assessment of on-pump CABG-induced subacute post-operative endothelial dysfunctions.
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Affiliation(s)
- V. GOMES
- Laboratory of Cardiovascular Investigation; Oswaldo Cruz Institute/FIOCRUZ; Rio de Janeiro Brazil
| | - M. B. GOMES
- Department of Internal Medicine; Diabetes Unit; State University of Rio de Janeiro; Rio de Janeiro Brazil
| | - E. TIBIRICA
- Laboratory of Cardiovascular Investigation; Oswaldo Cruz Institute/FIOCRUZ; Rio de Janeiro Brazil
| | - M. A. LESSA
- Laboratory of Cardiovascular Investigation; Oswaldo Cruz Institute/FIOCRUZ; Rio de Janeiro Brazil
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Effect of bariatric surgery on microvascular dysfunction associated to metabolic syndrome: a 12-month prospective study. Int J Obes (Lond) 2014; 38:1410-5. [PMID: 24468701 DOI: 10.1038/ijo.2014.15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/17/2013] [Accepted: 01/17/2014] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To prospectively evaluate the effect of weight loss after bariatric surgery on microvascular function in morbidly obese patients with and without metabolic syndrome (MetS). METHODS A cohort of morbidly obese patients with and without MetS was studied before surgery and after 12 months of surgery. Healthy lean controls were also examined. Microvascular function was assessed by postocclusive reactive hyperemia (PORH) at forearm skin evaluated by laser Doppler flowmetry (LDF). Cutaneous vascular conductance (CVC) was calculated from laser-Doppler skin blood flow and blood pressure. Regression analysis was performed to assess the contribution of different clinical, metabolic and biochemical parameters to microvascular function. RESULTS Before surgery, 62 obese patients, 39 with MetS and 23 without MetS, and 30 lean control subjects were analyzed. The absolute area under the hyperemic curve (AUC(H)) CVC of PORH was significantly decreased in obese patients compared with lean control subjects. One year after surgery, AUC(H) CVC significantly increased in patients free of MetS, including patients that had MetS before surgery. In contrast, AUC(H) CVC did not significantly change in patients in whom MetS persisted after surgery. Stepwise multivariate regression analysis showed that only changes in HDL cholesterol (HDL-C) and oxidized LDL (oxLDL) independently predicted improvement of AUC(H) after surgery. These two variables together accounted for 40.9% of the variability of change in AUC(H) CVC after surgery. CONCLUSIONS Bariatric surgery could significantly improve microvascular dysfunction in obese patients, but only in patients free of MetS after surgery. Improvement of microvascular dysfunction is strictly associated to postoperative increase in HDL-C levels and decrease in oxLDL levels.
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Humeau-Heurtier A, Abraham P, Mahe G. Linguistic Analysis of Laser Speckle Contrast Images Recorded at Rest and During Biological Zero: Comparison With Laser Doppler Flowmetry Data. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:2311-2321. [PMID: 24058017 DOI: 10.1109/tmi.2013.2281620] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Laser speckle contrast imaging (LSCI) is a newly commercialized imaging modality to monitor microvascular blood flow. Contrary to the well-known laser Doppler flowmetry (LDF), LSCI has the advantage of giving a full-field image of surface blood flow using simple instrumentation. However, laser speckle contrast images are not fully understood yet and their link with LDF signals still has to be studied. To quantify the similarity between LSCI and LDF symbolic sequences, we propose to use, for the first time, the index adapted from linguistic analysis and information theory proposed by Yang For this purpose, LSCI and LDF data were recorded simultaneously on the forearm of healthy subjects, at rest and during a vascular occlusion (biological zero). We show that there are different dynamical patterns for LSCI and LDF data, and the distances between these patterns differ through the space scales explored. Moreover, our results suggest that these different dynamical patterns could be linked to blood flow. The quantitative metric used herein therefore provides new information on LSCI and brings knowledge on links between LSCI and LDF.
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Petersen LJ. Direct comparison of laser Doppler flowmetry and laser Doppler imaging for assessment of experimentally-induced inflammation in human skin. Inflamm Res 2013; 62:1073-8. [DOI: 10.1007/s00011-013-0668-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 09/17/2013] [Indexed: 11/29/2022] Open
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Hartgill TW, Pirhonen J. Blood pressure rises more in pre-eclampsia than normal pregnancy when acral skin is locally cooled. Hypertens Pregnancy 2013; 32:340-54. [PMID: 23844619 DOI: 10.3109/10641955.2013.807820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Investigate blood pressure response to acral skin vasoconstriction in healthy and pre-eclamptic pregnancies. METHODS Healthy women were investigated from gestational week 8 to 52 weeks postpartum and pre-eclampsia subjects at diagnosis. Finger artery ultrasound Doppler, forearm laser Doppler fluximetry and photoplethysmographic blood pressure were recorded. Hand cooling to 19 °C induced vasoconstriction. RESULTS Acral skin vasoconstriction increases blood pressure from 16 weeks until 12 weeks postpartum (p ≤ 0.01), with greatest responses in pre-eclampsia (p=0.047). Forearm skin perfusion is higher in pre-eclampsia (p=0.04). CONCLUSION Acral skin vasoconstriction raises blood pressure in pregnancy, particularly in pre-eclampsia. Pregnancy accentuates important functional differences within skin.
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Affiliation(s)
- T W Hartgill
- Department of Obstetrics and Gynaecology, Oslo University Hospital , Oslo , Norway
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107
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Abraham P, Bourgeau M, Camo M, Humeau-Heurtier A, Durand S, Rousseau P, Mahe G. Effect of skin temperature on skin endothelial function assessment. Microvasc Res 2013; 88:56-60. [DOI: 10.1016/j.mvr.2013.04.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 04/18/2013] [Indexed: 11/16/2022]
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108
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Roustit M, Cracowski JL. Assessment of endothelial and neurovascular function in human skin microcirculation. Trends Pharmacol Sci 2013; 34:373-84. [DOI: 10.1016/j.tips.2013.05.007] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/03/2013] [Accepted: 05/17/2013] [Indexed: 10/26/2022]
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109
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Skin blood flow dynamics and its role in pressure ulcers. J Tissue Viability 2013; 22:25-36. [PMID: 23602509 DOI: 10.1016/j.jtv.2013.03.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 03/05/2013] [Accepted: 03/06/2013] [Indexed: 11/20/2022]
Abstract
Pressure ulcers are a significant healthcare problem affecting the quality of life in wheelchair bounded or bed-ridden people and are a major cost to the healthcare system. Various assessment tools such as the Braden scale have been developed to quantify the risk level of pressure ulcers. These tools have provided an initial guideline on preventing pressure ulcers while additional assessments are needed to improve the outcomes of pressure ulcer prevention. Skin blood flow function that determines the ability of the skin in response to ischemic stress has been proposed to be a good indicator for identifying people at risk of pressure ulcers. Wavelet spectral and nonlinear complexity analyses have been performed to investigate the influences of the metabolic, neurogenic and myogenic activities on microvascular regulation in people with various pathological conditions. These findings have contributed to the understanding of the role of ischemia and viability on the development of pressure ulcers. The purpose of the present review is to provide an introduction of the basic concepts and approaches for the analysis of skin blood flow oscillations, and present an overview of the research results obtained so far. We hope this information may contribute to the development of better clinical guidelines for the prevention of pressure ulcers.
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Humeau-Heurtier A, Mahe G, Durand S, Abraham P. Multiscale Entropy Study of Medical Laser Speckle Contrast Images. IEEE Trans Biomed Eng 2013; 60:872-9. [DOI: 10.1109/tbme.2012.2208642] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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111
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Humeau-Heurtier A, Guerreschi E, Abraham P, Mahe G. Relevance of Laser Doppler and Laser Speckle Techniques for Assessing Vascular Function: State of the Art and Future Trends. IEEE Trans Biomed Eng 2013; 60:659-66. [DOI: 10.1109/tbme.2013.2243449] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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112
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Increasing acclimation period improves the reproducibility of short-heating local thermal hyperemia. Microvasc Res 2013; 85:93-8. [DOI: 10.1016/j.mvr.2012.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/24/2012] [Accepted: 11/05/2012] [Indexed: 01/05/2023]
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113
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MAHÉ GUILLAUME, DURAND SYLVAIN, HUMEAU-HEURTIER ANNE, LEFTHERIOTIS GEORGES, ABRAHAM PIERRE. Impact of Experimental Conditions on Noncontact Laser Recordings in Microvascular Studies. Microcirculation 2012; 19:669-75. [DOI: 10.1111/j.1549-8719.2012.00205.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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114
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Millet C, Roustit M, Blaise S, Cracowski JL. Aging is associated with a diminished axon reflex response to local heating on the gaiter skin area. Microvasc Res 2012; 84:356-61. [DOI: 10.1016/j.mvr.2012.06.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 06/25/2012] [Accepted: 06/25/2012] [Indexed: 11/17/2022]
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115
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Humeau-Heurtier A, Mahé G, Durand S, Henrion D, Abraham P. Laser speckle contrast imaging: Multifractal analysis of data recorded in healthy subjects. Med Phys 2012; 39:5849-56. [DOI: 10.1118/1.4748506] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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116
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Huang CS, Wang SF, Tsai YF. Axon reflex-related hyperemia induced by short local heating is reproducible. Microvasc Res 2012; 84:351-5. [PMID: 22796314 DOI: 10.1016/j.mvr.2012.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/31/2012] [Accepted: 07/05/2012] [Indexed: 01/15/2023]
Abstract
OBJECTIVES The axon reflex (AR) flare is induced by antidromic activation of afferent C-fibers during nociceptive stimulation. This response has been suggested to be modulated by sympathetic activity and basal level of nitric oxide. In previously used protocols of local thermal hyperemia (LTH), AR flare has been used in combination with maximal vasodilatation to study the integrated endothelial function. The aim of this study was to investigate the intra-session reproducibility of short heating-induced AR flare, the specific neural-mediated portion of LTH, and to compare the reproducibility between different forms of data expression. METHODS Short-heating LTH was assessed using single-point laser Doppler flowmetry (LDF) on bilateral volar surface of the forearm in 10 men and 10 women. The blood flux measurement included a non-heating process for 5 min, followed by a quick heating process from 33°C to 42°C for 5 min. The test was repeated 45 min later at the same recording sites with fixed holders. Baseline and heating blood flux were recorded and expressed as different forms of data. Reproducibility was assessed using coefficient of variation (CV) and intra-class correlation coefficient (ICC) statistics. RESULTS The reproducibility of peak cutaneous vascular conductance (CVC) (CV=16.02-17.31%, ICC=0.77-0.78), peak CVC change (CV=14.30-18.12%, ICC=0.80-0.86), and the 4 min area-under-the-curve (CV=18.37-18.70%, ICC=0.60-0.78) was acceptable. The time to peak flux of each recording site ranged from 90 to 209 s and all the peak fluxes have been achieved before 4 min of heating. CONCLUSIONS Single-point LDF is a reproducible technique of assessing AR flare on volar surface of the forearm when the heating period is reduced to 5 min and the recording sites are fixed. Using this new protocol, short-heating LTH has a potential to be used to evaluate the effects of acute physical or chemical interventions between two short-heating LTH tests to further explore the pathophysiological meaning of heating-induced AR flare.
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Affiliation(s)
- Chung-Shin Huang
- Department of Physiology, College of Medicine, National Taiwan University, No. 1 Jen-Ai Road, Section 1, Taipei 100, Taiwan, ROC.
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117
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Tesselaar E, Bergkvist M, Sjöberg F, Farnebo S. Polarized light spectroscopy for measurement of the microvascular response to local heating at multiple skin sites. Microcirculation 2012; 19:705-13. [PMID: 22716906 DOI: 10.1111/j.1549-8719.2012.00203.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To evaluate whether TiVi, a technique based on polarized light, could measure the change in RBC concentration during local heating in healthy volunteers. METHODS Using a custom-made transparent heater, forearm skin was heated to 42 °C for 40 minutes while the change in RBC concentration was measured with TiVi. The perfusion response during local heating was measured at the same time with Laser Doppler flowmetry. RESULTS Mean RBC concentration increased (91 ± 34 vs. 51 ± 34 A.U. at baseline, p < 0.001). The spatial heterogeneity of the RBC concentration in the measured skin areas was 26 ± 6.4% at baseline, and 23 ± 4.6% after 40 minutes of heating. The mean RBC concentrations in two skin sites were highly correlated (0.98 at baseline and 0.96 after 40 minutes of heating). The change in RBC concentration was less than the change in perfusion, measured with LDF. Unlike with LDF, a neurally mediated peak was not observed with TiVi in most of the test subjects. CONCLUSIONS TiVi is a valuable technique for measuring the microvascular response to local heating in the skin, and offers a high reproducibility for simultaneous measurements at different skin sites, provided carefully controlled experiments are ensured.
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Affiliation(s)
- Erik Tesselaar
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
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118
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Bricq S, Mahé G, Rousseau D, Humeau-Heurtier A, Chapeau-Blondeau F, Rojas Varela J, Abraham P. Assessing spatial resolution versus sensitivity from laser speckle contrast imaging: application to frequency analysis. Med Biol Eng Comput 2012; 50:1017-23. [DOI: 10.1007/s11517-012-0919-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 05/13/2012] [Indexed: 10/28/2022]
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119
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Cracowski JL, Roustit M. Reproducibility of LDF blood flow measurements: Dynamical characterization versus averaging. A response to the letter from Stefanovska. Microvasc Res 2012; 83:97. [DOI: 10.1016/j.mvr.2011.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 12/20/2011] [Accepted: 12/21/2011] [Indexed: 11/28/2022]
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120
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Endurance exercise training enhances cutaneous microvascular reactivity in post-menopausal women. Microvasc Res 2012; 83:223-8. [DOI: 10.1016/j.mvr.2011.09.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 08/04/2011] [Accepted: 09/09/2011] [Indexed: 12/21/2022]
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121
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Mahé G, Humeau-Heurtier A, Durand S, Leftheriotis G, Abraham P. Assessment of Skin Microvascular Function and Dysfunction With Laser Speckle Contrast Imaging. Circ Cardiovasc Imaging 2012; 5:155-63. [DOI: 10.1161/circimaging.111.970418] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Guillaume Mahé
- From the Laboratory of Vascular Investigations, University Hospital of Angers and Biologie Neurovasculaire et Mitochondriale Intégrée (BNMI)-Unité mixte UMR CNRS 6214/INSERM 771, Faculté de Médecine, Angers, France (G.M., G.L., P.A.); Laboratoire d'Ingénierie des Systèmes Automatisés (LISA), Université d'Angers, Angers, France (A.H.-H.); and Laboratory “Motricité, Interactions, Performance” EA 4334, University of Le Mans, Faculty of Sport Sciences, Le Mans, France (S.D.)
| | - Anne Humeau-Heurtier
- From the Laboratory of Vascular Investigations, University Hospital of Angers and Biologie Neurovasculaire et Mitochondriale Intégrée (BNMI)-Unité mixte UMR CNRS 6214/INSERM 771, Faculté de Médecine, Angers, France (G.M., G.L., P.A.); Laboratoire d'Ingénierie des Systèmes Automatisés (LISA), Université d'Angers, Angers, France (A.H.-H.); and Laboratory “Motricité, Interactions, Performance” EA 4334, University of Le Mans, Faculty of Sport Sciences, Le Mans, France (S.D.)
| | - Sylvain Durand
- From the Laboratory of Vascular Investigations, University Hospital of Angers and Biologie Neurovasculaire et Mitochondriale Intégrée (BNMI)-Unité mixte UMR CNRS 6214/INSERM 771, Faculté de Médecine, Angers, France (G.M., G.L., P.A.); Laboratoire d'Ingénierie des Systèmes Automatisés (LISA), Université d'Angers, Angers, France (A.H.-H.); and Laboratory “Motricité, Interactions, Performance” EA 4334, University of Le Mans, Faculty of Sport Sciences, Le Mans, France (S.D.)
| | - Georges Leftheriotis
- From the Laboratory of Vascular Investigations, University Hospital of Angers and Biologie Neurovasculaire et Mitochondriale Intégrée (BNMI)-Unité mixte UMR CNRS 6214/INSERM 771, Faculté de Médecine, Angers, France (G.M., G.L., P.A.); Laboratoire d'Ingénierie des Systèmes Automatisés (LISA), Université d'Angers, Angers, France (A.H.-H.); and Laboratory “Motricité, Interactions, Performance” EA 4334, University of Le Mans, Faculty of Sport Sciences, Le Mans, France (S.D.)
| | - Pierre Abraham
- From the Laboratory of Vascular Investigations, University Hospital of Angers and Biologie Neurovasculaire et Mitochondriale Intégrée (BNMI)-Unité mixte UMR CNRS 6214/INSERM 771, Faculté de Médecine, Angers, France (G.M., G.L., P.A.); Laboratoire d'Ingénierie des Systèmes Automatisés (LISA), Université d'Angers, Angers, France (A.H.-H.); and Laboratory “Motricité, Interactions, Performance” EA 4334, University of Le Mans, Faculty of Sport Sciences, Le Mans, France (S.D.)
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ROUSTIT MATTHIEU, CRACOWSKI JEANLUC. Non-invasive Assessment of Skin Microvascular Function in Humans: An Insight Into Methods. Microcirculation 2011; 19:47-64. [DOI: 10.1111/j.1549-8719.2011.00129.x] [Citation(s) in RCA: 194] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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123
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FRANTZ JOHANNA, ENGELBERGER ROLFPETER, LIAUDET LUCAS, MAZZOLAI LUCIA, WAEBER BERNARD, FEIHL FRANÇOIS. Desensitization of Thermal Hyperemia in the Skin is Reproducible. Microcirculation 2011; 19:78-85. [DOI: 10.1111/j.1549-8719.2011.00124.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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124
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Impact of 10 sessions of whole body cryostimulation on cutaneous microcirculation measured by laser Doppler flowmetry. J Hum Kinet 2011; 30:75-83. [PMID: 23487007 PMCID: PMC3588644 DOI: 10.2478/v10078-011-0075-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The aim of the present study was to evaluate the basic and evoked blood flow in the skin microcirculation of the hand, one day and ten days after a series of 10 whole body cryostimulation sessions, in healthy individuals. The study group included 32 volunteers – 16 women and 16 men. The volunteers underwent 10 sessions of cryotherapy in a cryogenic chamber. The variables were recorded before the series of 10 whole body cryostimulation sessions (first measurement), one day after the last session (second measurement) and ten days later (third measurement). Rest flow, post-occlusive hyperaemic reaction, reaction to temperature and arterio–venous reflex index were evaluated by laser Doppler flowmetry. The values recorded for rest flow, a post-occlusive hyperaemic reaction, a reaction to temperature and arterio – venous reflex index were significantly higher both in the second and third measurement compared to the initial one. Differences were recorded both in men and women. The values of frequency in the range of 0,01 Hz to 2 Hz (heart frequency dependent) were significantly lower after whole-body cryostimulation in both men and women. In the range of myogenic frequency significantly higher values were recorded in the second and third measurement compared to the first one. Recorded data suggest improved response of the cutaneous microcirculation to applied stimuli in both women and men. Positive effects of cryostimulation persist in the tested group for 10 consecutive days.
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Reproducibility of LDF blood flow measurements: Dynamical characterization versus averaging. Microvasc Res 2011; 82:274-6. [DOI: 10.1016/j.mvr.2011.08.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 08/25/2011] [Indexed: 11/21/2022]
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126
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Distance between laser head and skin does not influence skin blood flow values recorded by laser speckle imaging. Microvasc Res 2011; 82:439-42. [DOI: 10.1016/j.mvr.2011.06.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 06/27/2011] [Accepted: 06/30/2011] [Indexed: 11/19/2022]
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127
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Brunt VE, Miner JA, Meendering JR, Kaplan PF, Minson CT. 17β-estradiol and progesterone independently augment cutaneous thermal hyperemia but not reactive hyperemia. Microcirculation 2011; 18:347-55. [PMID: 21426437 DOI: 10.1111/j.1549-8719.2011.00095.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE We examined the impact of estradiol and progesterone on skin LH and RH in 25 healthy women. METHODS Subjects were studied three times over 10-12 days. Endogenous sex hormones were suppressed with a GnRHa. Subjects were studied on day 4 of suppression (study day 1), three to four days later following treatment with either 17β-estradiol or progesterone (study day 2), and another three to four days later, following treatment with both estradiol and progesterone (study day 3). Subjects underwent identical LH and RH protocols on all study days. LH is characterized by an initial peak in blood flow, followed by a prolonged plateau. A brief nadir is seen between the phases. RESULTS Blood flow values are expressed as percent maximum CVC. Estradiol alone increased initial peak CVC from 71 ± 2% to 79 ± 2% (p = 0.001). Progesterone alone increased initial peak CVC from 72 ± 2% to 78 ± 2% (p = 0.046). Neither estradiol nor progesterone increased plateau CVC. No significant changes were seen between study days 2 and 3 for either group. No differences were observed in RH. CONCLUSIONS Both estradiol and progesterone increased initial peak CVC during LH, without altering plateau CVC. There was no additive effect of estradiol and progesterone.
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Affiliation(s)
- Vienna E Brunt
- Department of Human Physiology, University of Oregon, Eugene, Oregon, USA
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Cracowski JL, Gaillard-Bigot F, Cracowski C, Roustit M, Millet C. Skin microdialysis coupled with laser speckle contrast imaging to assess microvascular reactivity. Microvasc Res 2011; 82:333-8. [PMID: 22001188 DOI: 10.1016/j.mvr.2011.09.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 09/21/2011] [Accepted: 09/26/2011] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Laser speckle contrast imaging (LSCI) can be used to assess real-time responses of skin microcirculation to pharmacological interventions. The main objective of this study was to determine whether intradermal or subdermal microdialysis fiber insertion, coupled with skin flux recording using LSCI, can be used to assess baseline cutaneous flux and the post-occlusive reactive hyperemic response. The microdialysis sites were compared to control area without microdialysis fibers. METHODS One dermal and two subdermal microdialysis fibers were randomly inserted in the right forearm skin of six healthy volunteers. We performed consecutively tests of post-occlusive hyperemia, infusion of 29 mM sodium nitroprusside (SNP), local thermal hyperemia at 43°C and a second 29 mM SNP infusion at the end of the experiment. RESULTS Two hours after fiber insertion, cutaneous vascular conductances (CVC) at the subdermal fiber sites were not different from their respective control regions of interest, while at the dermal site CVC remained higher (0.48+/-0.15 versus 0.37+/-0.1 PU.mm Hg(-1), P=0.003). The peak CVC and area under the curve observed during post-occlusive reactive hyperemia were similar at all fiber sites and their respective controls. We observed a similar increase in CVC using 29 mM SNP infusion, 40 min local heating at 43°C, and their combination. Finally, physiological and pharmacological responses of the subdermal sites were reproducible in terms of amplitude, whether expressed as raw CVC or as % CVCmax. CONCLUSIONS We showed that studying skin microvascular physiological or pharmacological responses using inserted subdermal microdialysis fibers coupled with LSCI is feasible and reproducible, and provides two-dimensional information. This technique will be useful for future mechanistic studies of skin microcirculation.
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Affiliation(s)
- J L Cracowski
- Clinical Pharmacology Department, Inserm CIC3, University Hospital, Grenoble, France.
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Engelberger RP, Blazek C, Amsler F, Keo HH, Baumann F, Blättler W, Baumgartner I, Willenberg T. Reproducibility and day time bias correction of optoelectronic leg volumetry: a prospective cohort study. BMC Med Res Methodol 2011; 11:138. [PMID: 21974893 PMCID: PMC3198754 DOI: 10.1186/1471-2288-11-138] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 10/05/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Leg edema is a common manifestation of various underlying pathologies. Reliable measurement tools are required to quantify edema and monitor therapeutic interventions. Aim of the present work was to investigate the reproducibility of optoelectronic leg volumetry over 3 weeks' time period and to eliminate daytime related within-individual variability. METHODS Optoelectronic leg volumetry was performed in 63 hairdressers (mean age 45 ± 16 years, 85.7% female) in standing position twice within a minute for each leg and repeated after 3 weeks. Both lower leg (legBD) and whole limb (limbBF) volumetry were analysed. Reproducibility was expressed as analytical and within-individual coefficients of variance (CVA, CVW), and as intra-class correlation coefficients (ICC). RESULTS A total of 492 leg volume measurements were analysed. Both legBD and limbBF volumetry were highly reproducible with CVA of 0.5% and 0.7%, respectively. Within-individual reproducibility of legBD and limbBF volumetry over a three weeks' period was high (CVW 1.3% for both; ICC 0.99 for both). At both visits, the second measurement revealed a significantly higher volume compared to the first measurement with a mean increase of 7.3 ml ± 14.1 (0.33% ± 0.58%) for legBD and 30.1 ml ± 48.5 ml (0.52% ± 0.79%) for limbBF volume. A significant linear correlation between absolute and relative leg volume differences and the difference of exact day time of measurement between the two study visits was found (P < .001). A therefore determined time-correction formula permitted further improvement of CVW. CONCLUSIONS Leg volume changes can be reliably assessed by optoelectronic leg volumetry at a single time point and over a 3 weeks' time period. However, volumetry results are biased by orthostatic and daytime-related volume changes. The bias for day-time related volume changes can be minimized by a time-correction formula.
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Affiliation(s)
- Rolf P Engelberger
- Swiss Cardiovascular Center, Division of Clinical and Interventional Angiology Inselspital, University Hospital and University of Bern, Switzerland
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Figueiras E, Roustit M, Semedo S, Ferreira LR, Crascowski J, Humeau A. Sample entropy of laser Doppler flowmetry signals increases in patients with systemic sclerosis. Microvasc Res 2011; 82:152-5. [DOI: 10.1016/j.mvr.2011.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 05/10/2011] [Accepted: 05/24/2011] [Indexed: 10/18/2022]
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Millet C, Roustit M, Blaise S, Cracowski J. Comparison between laser speckle contrast imaging and laser Doppler imaging to assess skin blood flow in humans. Microvasc Res 2011; 82:147-51. [DOI: 10.1016/j.mvr.2011.06.006] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 05/31/2011] [Accepted: 06/15/2011] [Indexed: 10/18/2022]
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BLAISE SOPHIE, ROUSTIT MATHIEU, MILLET CLAIRE, CRACOWSKI JEANLUC. Effect of Oral Sildenafil on Skin Postocclusive Reactive Hyperemia in Healthy Volunteers. Microcirculation 2011; 18:448-51. [DOI: 10.1111/j.1549-8719.2011.00105.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Tew GA, Klonizakis M, Crank H, Briers JD, Hodges GJ. Comparison of laser speckle contrast imaging with laser Doppler for assessing microvascular function. Microvasc Res 2011; 82:326-32. [PMID: 21803051 DOI: 10.1016/j.mvr.2011.07.007] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 07/06/2011] [Accepted: 07/14/2011] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To compare the inter-day reproducibility of post-occlusive reactive hyperaemia (PORH) and sympathetic vasomotor reflexes assessed by single-point laser Doppler flowmetry (SP-LDF), integrating-probe LDF (IP-LDF) and laser speckle contrast imaging (LSCI), and the spatial variability of PORH assessed by IP-LDF and LSCI. We also evaluated the relationship between IP-LDF and LSCI perfusion values across a broad range of skin blood flows. METHODS Eighteen healthy adults (50% male, age 27 ± 4 years) participated in this study. Using SP-LDF, IP-LDF and LSCI, indices of skin blood flow were measured on the forearm during PORH (1-, 5- and 10-min occlusions) and on the finger pad during inspiratory gasp and cold pressor tests. These tests were repeated 3-7 days later. Data were converted to cutaneous vascular conductance (CVC; laser Doppler flow/mean arterial pressure) and expressed as absolute and relative changes from pre-stimulus CVC (ΔCVC(ABS) and ΔCVC(REL), respectively), as well as normalised to peak CVC for the PORH tests. Reproducibility was expressed as within-subjects coefficients of variation (CV, in %) and intraclass correlation coefficients. RESULTS The reproducibility of PORH on the forearm was poorer when assessed with SP-LDF and IP-LDF compared to LSCI (e.g., CV for 5-min PORH ΔCVC(ABS)=35%, 27% and 19%, respectively), with no superior method of data expression. In contrast, the reproducibility of the inspiratory gasp and cold pressor test responses on the finger pad were better with SP-LDF and IP-LDF compared to LSCI (e.g., CV for inspiratory gasp ΔCVC(REL)=13%, 7% and 19%, respectively). The spatial variability of PORH responses was poorer with IP-LDF compared to LSCI (e.g., CV ranging 11-35% versus 3-16%, respectively). The association between simultaneous LSCI and IP-LDF perfusion values was non-linear. CONCLUSION The reproducibility of cutaneous PORH was better when assessed with LSCI compared to SP-LDF and IP-LDF; probably due to measuring larger skin areas (lower inter-site variability). However, when measuring sympathetic vasomotor reflexes on the finger pad, reproducibility was better with SP-LDF and IP-LDF, perhaps due to the high sensitivity of LSCI to changes in skin blood flow at low levels.
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Affiliation(s)
- Garry A Tew
- Centre for Sport and Exercise Science, Sheffield Hallam University, A125 Collegiate Hall, Sheffield, S10 2BP, UK.
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Influence of polymeric microspheres on the myocardial oxygen partial pressure in the beating heart of pigs. Microvasc Res 2011; 82:52-7. [DOI: 10.1016/j.mvr.2011.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 04/03/2011] [Indexed: 11/18/2022]
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Sheppard LW, Vuksanović V, McClintock PVE, Stefanovska A. Oscillatory dynamics of vasoconstriction and vasodilation identified by time-localized phase coherence. Phys Med Biol 2011; 56:3583-601. [PMID: 21606559 DOI: 10.1088/0031-9155/56/12/009] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We apply wavelet-based time-localized phase coherence to investigate the relationship between blood flow and skin temperature, and between blood flow and instantaneous heart rate (IHR), during vasoconstriction and vasodilation provoked by local cooling or heating of the skin. A temperature-controlled metal plate (approximately 10 cm2) placed on the volar side of the left arm was used to provide the heating and cooling. Beneath the plate, the blood flow was measured by laser Doppler flowmetry and the adjacent skin temperature by a thermistor. Two 1 h datasets were collected from each of the ten subjects. In each case a 30 min basal recording was followed by a step change in plate temperature, to either 24 °C or 42 °C. The IHR was derived from simultaneously recorded ECG. We confirm the changes in the energy and frequency of blood flow oscillations during cooling and heating reported earlier. That is, during cooling, there was a significant decrease in the average frequency of myogenic blood flow oscillations (p < 0.05) and the myogenic spectral peak became more prominent. During heating, there was a significant (p < 0.05) general increase in spectral energy, associated with vasodilation, except in the myogenic interval. Weak phase coherence between temperature and blood flow was observed for unperturbed skin, but it increased in all frequency intervals as a result of heating. It was not significantly affected by cooling. We also show that significant (p < 0.05) phase coherence exists between blood flow and IHR in the respiratory and myogenic frequency intervals. Cooling did not affect this phase coherence in any of the frequency intervals, whereas heating enhanced the phase coherence in the respiratory and myogenic intervals. This can be explained by the reduction in vascular resistance produced by heating, a process where myogenic mechanisms play a key role. We conclude that the mechanisms of vasodilation and vasoconstriction, in response to temperature change, are oscillatory in nature and are independent of central sources of variability.
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Affiliation(s)
- L W Sheppard
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK
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Clough GF, L'Esperance V, Turzyniecka M, Walter L, Chipperfield AJ, Gamble J, Krentz AJ, Byrne CD. Functional dilator capacity is independently associated with insulin sensitivity and age in central obesity and is not improved by high dose statin treatment. Microcirculation 2011; 18:74-84. [PMID: 21166928 DOI: 10.1111/j.1549-8719.2010.00070.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To test the hypothesis that: (i) functional microvascular dilator capacity is independently associated with insulin sensitivity and age in individuals with central adiposity at risk of cardiovascular disease (CVD); and (ii) functional microvascular dilator capacity is improved by high dose statin treatment. METHODS Functional dilator capacity (measured as change in laser Doppler blood flux from baseline during post occlusive reactive hyperemia [peak flux%resting flux; PF%RF] and flowmotion (power spectral density [PSD] analysis)) were assessed in 40 people with central adiposity and one or more other CVD risk factors. Measurements were made at rest and during acute hyperinsulinaemia before and six months after high dose atorvastatin (40 mg daily) or placebo. RESULTS Insulin-induced change in PF%RF was independently associated with insulin sensitivity (M/I) (r = 0.46 p = 0.02) and age (r = -0.46 p = 0.02), which together explained almost half of the variance in PF%RF (adjusted r² = 0.37, p = 0.008). Whilst atorvastatin decreased LDL cholesterol by 51% (p < 0.001), PF%RF and flowmotion remained unchanged. CONCLUSIONS Insulin sensitivity and age are independently associated with an insulin-induced change in functional microvascular dilator capacity in individuals with central adiposity at risk of CVD. Dilator capacity is not improved by six months high dose statin treatment.
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Affiliation(s)
- Geraldine F Clough
- Institute of Developmental Sciences, School of Medicine, University of Southampton, Southampton General Hospital (MP 887), Southampton, UK.
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Delgado-Lista J, Garcia-Rios A, Perez-Martinez P, Fuentes F, Jiménez-Gomez Y, Gomez-Luna MJ, Parnell LD, Marin C, Lai CQ, Perez-Jimenez F, Ordovas JM, Lopez-Miranda J. Gene variations of nitric oxide synthase regulate the effects of a saturated fat rich meal on endothelial function. Clin Nutr 2011; 30:234-8. [DOI: 10.1016/j.clnu.2010.08.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Revised: 08/17/2010] [Accepted: 08/23/2010] [Indexed: 10/19/2022]
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HENRICSON JOAKIM, TESSELAAR ERIK, BAIAT YASHMA, NILSSON GERT, SJÖBERG FOLKE. Local Heating as a Predilatation Method for Measurement of Vasoconstrictor Responses with Laser-Doppler Flowmetry. Microcirculation 2011; 18:214-20. [DOI: 10.1111/j.1549-8719.2010.00079.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Rousseau P, Mahé G, Haj-Yassin F, Durand S, Humeau A, Leftheriotis G, Abraham P. Increasing the "region of interest" and "time of interest", both reduce the variability of blood flow measurements using laser speckle contrast imaging. Microvasc Res 2011; 82:88-91. [PMID: 21439303 DOI: 10.1016/j.mvr.2011.03.009] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 03/11/2011] [Accepted: 03/15/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Both spatial variability and temporal variability of skin blood flow are high. Laser speckle contrast imagers (LSCI) allow non-contact, real-time recording of cutaneous blood flow on large skin surfaces. Thereafter, the observer can define different sizes for the region of interest (ROI) in the images to decrease spatial variability and different durations over which the blood flow values are averaged (time of interest, TOI) to decrease temporal variability. We aimed to evaluate the impact of the choices of ROI and TOI on the analysis of rest blood flow and post occlusive reactive hyperemia (PORH). METHODS Cutaneous blood flow (CBF) was assessed at rest and during PORH. Three different sizes of ROI (1mm(2), 10mm(2) and 100mm(2)), and three different TOI (CBF averaged over 1s, 15s, and 30s for rest, and over 1s, 5s and 10s for PORH peak) were evaluated. Inter-subjects and intra-subjects coefficient of variations (inter-CV and intra-CV) were studied. RESULTS The inter-subject variability of CBF is about 25% at rest and is moderately improved when the size of the ROI increases (inter-CV=31%, for 1s and 1mm(2) versus inter-CV=23%, for 15s and 100mm(2)). However, increasing the TOI does not improve the results. The variability of the PORH peak is lower with an inter-CV varying between 11.4% (10s and 100mm(2)) and 21.6% (5s and 1mm(2)). The lowest intra-CV for the CBF at rest was 7.3% (TOI of 15s on a ROI of 100mm(2)) and was 3.1% for the PORH peak (TOI of 10s on a ROI of 100mm(2)). CONCLUSION We suggest that a size of ROI larger than 10mm(2) and a TOI longer than 1s are required to reduce the variability of CBF measurements both at rest and during PORH peak evaluations at the forearm level. Many technical aspects such as comparison of laser speckle contrast imaging and laser Doppler imaging or the effect of skin to head distance on recorded values with LCSI are required to improve future studies using this fascinating clinical tool.
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Affiliation(s)
- Pascal Rousseau
- Laboratory of Vascular Investigations, University Hospital of Angers, France
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Tew GA, Klonizakis M, Moss J, Ruddock AD, Saxton JM, Hodges GJ. Reproducibility of cutaneous thermal hyperaemia assessed by laser Doppler flowmetry in young and older adults. Microvasc Res 2011; 81:177-82. [DOI: 10.1016/j.mvr.2010.12.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 12/07/2010] [Accepted: 12/09/2010] [Indexed: 10/18/2022]
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Tibiriçá E, Matheus ASM, Nunes B, Sperandei S, Gomes MB. Repeatability of the evaluation of systemic microvascular endothelial function using laser doppler perfusion monitoring: clinical and statistical implications. Clinics (Sao Paulo) 2011; 66:599-605. [PMID: 21655753 PMCID: PMC3152722 DOI: 10.1590/s1807-59322011000400013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 11/01/2011] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE An awareness of the repeatability of biological measures is required to properly design and calculate sample sizes for longitudinal interventional studies. We investigated the day-to-day repeatability of measures of systemic microvascular reactivity using laser Doppler perfusion monitoring. METHODS We performed laser Doppler perfusion monitoring in combination with skin iontophoresis using acetylcholine and sodium nitroprusside as well as post-occlusive reactive and thermal hyperemia twice within two weeks. The repeatability was assessed by calculating the within-subject standard deviations, limits of agreement, typical errors and intra-class correlation coefficients between days 1 and 2. The ratio of the within-subject standard deviation to the mean values obtained on days 1 and 2 (within-subject standard deviation/GM) was used to determine the condition with the best repeatability. RESULTS Twenty-four healthy subjects, aged 24.6 ± 3.8 years, were recruited. The area under the curve of the vasodilatory response to post-occlusive reactivity showed marked variability (within-subject standard deviation/GM = 0.83), while the area under the curve for acetylcholine exhibited less variability (within-subject standard deviation/ GM = 0.52) and was comparable to the responses to sodium nitroprusside and thermal treatment (within-subject standard deviations/GM of 0.67 and 0.56, respectively). The area under the blood flow/time curve for vasodilation during acetylcholine administration required the smallest sample sizes, the area under the blood flow/time curve during post-occlusive reactivity required the largest sample sizes, and the area under the blood flow/time curves of vasodilation induced by sodium nitroprusside and thermal treatment required intermediate sizes. CONCLUSIONS In view of the importance of random error related to the day-to-day repeatability of laser Doppler perfusion monitoring, we propose an original and robust statistical methodology for use in designing prospective clinical studies.
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Mahé G, Rousseau P, Durand S, Bricq S, Leftheriotis G, Abraham P. Laser speckle contrast imaging accurately measures blood flow over moving skin surfaces. Microvasc Res 2010; 81:183-8. [PMID: 21156183 DOI: 10.1016/j.mvr.2010.11.013] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 11/29/2010] [Accepted: 11/30/2010] [Indexed: 12/01/2022]
Abstract
Cutaneous blood flow (CBF) can be assessed non-invasively with lasers. Unfortunately, movement artefacts in the laser skin signal (LS(sk)) might sometimes compromise the interpretation of the data. To date, no method is available to remove movement artefacts point-by-point. Using a laser speckle contrast imager, we simultaneously recorded LS(sk) and the signal backscattered from an adjacent opaque surface (LS(os)). The completion of a first protocol allowed a definition of a simple equation to calculate the CBF from movement artefact-affected traces of LS(sk) and LS(os). We then recorded LS(sk) and LS(os) before, during and for 5 min after the tourniquet ischemia, both when subjects (n=8) were immobile or submitted to external passive movements of random intensity throughout the test. The typical post-occlusive reactive hyperemia trace was not identifiable within the LS(sk) recordings, with LS(sk) being 2 to 3 times higher during movements than in the immobile situation. After the calculation of CBF, traces in the immobile versus movement conditions were comparable, with the "r" cross-correlation coefficient being 0.930+/-0.010. Our method might facilitate future investigations in microvascular physiology and pathophysiology, specifically in subjects who have frequent or continuous involuntary movements.
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Affiliation(s)
- Guillaume Mahé
- Laboratory of Vascular Investigations, University Hospital of Angers, France
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Stirban A, Nandrean S, Götting C, Tschoepe D, Tamler R. Reply to C Opländer. Am J Clin Nutr 2010. [DOI: 10.3945/ajcn.2010.29821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Alin Stirban
- Heart and Diabetes Center NRW, Bad Oeynhausen, Germany
| | | | | | | | - Ronald Tamler
- Division of Endocrinology, Diabetes, and Bone Diseases, The Mount Sinai Medical Center, New York, NY
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Minson CT. Thermal provocation to evaluate microvascular reactivity in human skin. J Appl Physiol (1985) 2010; 109:1239-46. [PMID: 20507974 DOI: 10.1152/japplphysiol.00414.2010] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
With increased interest in predictive medicine, development of a relatively noninvasive technique that can improve prediction of major clinical outcomes has gained considerable attention. Current tests that are the target of critical evaluation, such as flow-mediated vasodilation of the brachial artery and pulse-wave velocity, are specific to the larger conduit vessels. However, evidence is mounting that functional changes in the microcirculation may be an early sign of globalized microvascular dysfunction. Thus development of a test of microvascular reactivity that could be used to evaluate cardiovascular risk or response to treatment is an exciting area of innovation. This mini-review is focused on tests of microvascular reactivity to thermal stimuli in the cutaneous circulation. The skin may prove to be an ideal site for evaluation of microvascular dysfunction due to its ease of access and growing evidence that changes in skin vascular reactivity may precede overt clinical signs of disease. Evaluation of the skin blood flow response to locally applied heat has already demonstrated prognostic utility, and the response to local cooling holds promise in patients in whom cutaneous disorders are present. Whether either of these tests can be used to predict cardiovascular morbidity or mortality in a clinical setting requires further evaluation.
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