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Cooper KM, Colletta A, Moulton K, Ralto KM, Devuni D. Kidney disease in patients with chronic liver disease: Does sex matter? World J Clin Cases 2023; 11:3980-3992. [PMID: 37388789 PMCID: PMC10303604 DOI: 10.12998/wjcc.v11.i17.3980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/30/2023] [Accepted: 05/16/2023] [Indexed: 06/12/2023] Open
Abstract
Kidney disease in patients with liver disease is serious and increases mortality. Up to 50% of patients hospitalized experience an episode of acute kidney injury. In general, men with liver disease are thought to be at increased risk of kidney disease. However, this association should be considered with caution because most studies use creatinine-based inclusion criteria, which is negatively biased against women. In this review, we synthesize data on sex differences in kidney disease in patients with chronic liver disease in the clinical setting and discuss potential physiologic underpinnings.
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Affiliation(s)
- Katherine M Cooper
- Department of Medicine, UMass Chan Medical School, Worcester, MA 01665, United States
| | - Alessandro Colletta
- Department of Medicine, UMass Chan Medical School, Worcester, MA 01665, United States
| | - Kristen Moulton
- Department of Medicine, Division of Gastroenterology, UMass Chan Medical School, Worcester, MA 01665, United States
| | - Kenneth M Ralto
- Department of Medicine, Division of Renal Medicine, UMass Chan Medical School, Worcester, MA 01665, United States
| | - Deepika Devuni
- Department of Medicine, Division of Gastroenterology, UMass Chan Medical School, Worcester, MA 01665, United States
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2
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Kagelmann N, Janke D, Maggioni MA, Gunga HC, Riveros Rivera A, Genov M, Noppe A, Habazettl H, Bothe TL, Nordine M, Castiglioni P, Opatz O. Peripheral skin cooling during hyper-gravity: hemodynamic reactions. Front Physiol 2023; 14:1173171. [PMID: 37256071 PMCID: PMC10225582 DOI: 10.3389/fphys.2023.1173171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/27/2023] [Indexed: 06/01/2023] Open
Abstract
Introduction: Orthostatic dysregulation occurs during exposure to an increased gravitational vector and is especially common upon re-entering standard Earth gravity (1 g) after an extended period in microgravity (0 g). External peripheral skin cooling (PSC) has recently been described as a potent countermeasure against orthostatic dysregulation during heat stress and in lower body negative pressure (LBNP) studies. We therefore hypothesized that PSC may also be an effective countermeasure during hyper-gravity exposure (+Gz). Methods: To investigate this, we designed a randomized short-arm human centrifuge (SAHC) experiment ("Coolspin") to investigate whether PSC could act as a stabilizing factor in cardiovascular function during +Gz. Artificial gravity between +1 g and +4 g was generated by a SAHC. 18 healthy male volunteers completed two runs in the SAHC. PSC was applied during one of the two runs and the other run was conducted without cooling. Each run consisted of a 10-min baseline trial followed by a +Gz step protocol marked by increasing g-forces, with each step being 3 min long. The following parameters were measured: blood pressure (BP), heart rate (HR), stroke volume (SV), total peripheral resistance (TPR), cardiac output (CO). Furthermore, a cumulative stress index for each subject was calculated. Results: +Gz led to significant changes in primary as well as in secondary outcome parameters such as HR, SV, TPR, CO, and BP. However, none of the primary outcome parameters (HR, cumulative stress-index, BP) nor secondary outcome parameters (SV, TPR, CO) showed any significant differences-whether the subject was cooled or not cooled. Systolic BP did, however, tend to be higher amongst the PSC group. Conclusion: In conclusion, PSC during +Gz did not confer any significant impact on hemodynamic activity or orthostatic stability during +Gz. This may be due to lower PSC responsiveness of the test subjects, or an insufficient level of body surface area used for cooling. Further investigations are warranted in order to comprehensively pinpoint the exact degree of PSC needed to serve as a useful countermeasure system during +Gz.
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Affiliation(s)
- Niklas Kagelmann
- Charité—Universitätsmedizin Berlin, Institute of Physiology, Center for Space Medicine and Extreme Environments Berlin, Berlin, Germany
| | - David Janke
- Charité—Universitätsmedizin Berlin, Institute of Physiology, Center for Space Medicine and Extreme Environments Berlin, Berlin, Germany
| | - Martina Anna Maggioni
- Charité—Universitätsmedizin Berlin, Institute of Physiology, Center for Space Medicine and Extreme Environments Berlin, Berlin, Germany
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - Hanns-Christian Gunga
- Charité—Universitätsmedizin Berlin, Institute of Physiology, Center for Space Medicine and Extreme Environments Berlin, Berlin, Germany
| | - Alain Riveros Rivera
- Department of Physiological Sciences, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Magdalena Genov
- Charité—Universitätsmedizin Berlin, Institute of Physiology, Center for Space Medicine and Extreme Environments Berlin, Berlin, Germany
| | - Alexandra Noppe
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany
| | - Helmut Habazettl
- Charité—Universitätsmedizin Berlin, Institute of Physiology, Center for Space Medicine and Extreme Environments Berlin, Berlin, Germany
| | - Tomas Lucca Bothe
- Charité—Universitätsmedizin Berlin, Institute of Physiology, Center for Space Medicine and Extreme Environments Berlin, Berlin, Germany
- Charité—Universitätsmedizin Berlin, Institute of Translational Physiology, Berlin, Germany
| | - Michael Nordine
- Department of Anaesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt, Germany
| | - Paolo Castiglioni
- Department of Biotechnology and Life Sciences (DBSV), University of Insubria, Varese, Italy
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy
| | - Oliver Opatz
- Charité—Universitätsmedizin Berlin, Institute of Physiology, Center for Space Medicine and Extreme Environments Berlin, Berlin, Germany
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Rusinovich Y, Rusinovich V. Respiratory changes in biometry of suprarenal inferior vena cava in patients with varicose veins of lower extremities. Phlebology 2020; 36:313-321. [PMID: 33201763 DOI: 10.1177/0268355520974135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AIM This study examines respiratory biometry of inferior vena cava in patients with varicose veins of lower extremities. MATERIAL AND METHODS We performed retrospective analysis of clinical and ultrasound data of 67 patients with primary varicose veins. RESULTS The largest expiratory (mean 16.2 mm, p-value 0.09) and inspiratory (mean 8.2 mm, p-value 0.02) inferior vena cava diameters were in C3 Clinical Etiological Anatomical Pathophysiological clinical class; the smallest expiratory diameters (mean 13.1 mm, p-value 0.5) were in C6 class; the smallest inspiratory diameters (mean 4.6 mm, intercept) were in C2 class. C2 class was associated with highest inferior vena cava collapsibility index (mean 68.2%, intercept); C6 class was associated with lowest collapsibility index (mean 48.3%, p-value 0.04).Recurrent varices in comparison with previously untreated were associated with smaller inspiratory diameters of inferior vena cava (mean 4.4 mm, p-value 0.005), smaller expiratory diameters (mean 13.4 mm, p-value 0.06) and higher collapsibility index (mean 68.5%, p-value 0.005). Patients with recurrent and bilateral varicose veins had identical respiratory biometry of inferior vena cava.Older age was associated with smaller inferior vena cava diameters (p-value <0.01). CONCLUSION Clinical presentation of varicose veins is associated with different respiratory biometry of suprarenal inferior vena cava. C6 clinical class in comparison with C2 clinical class is associated with lower central venous compliance possible due to the narrowing of inferior vena cava. Smaller inferior vena cava diameters and higher collapsibility index in recurrent subgroup in comparison with previously untreated can be a sign of the significantly altered pressure gradient between the systemic capillaries and the right heart and impaired peripheral venous return. Narrowing of inferior vena cava with age can be a sign of more profound changes in systemic venous return with age in patients with varicose veins in comparison to those without chronic venous disease.
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Affiliation(s)
- Yury Rusinovich
- Department of Vascular Surgery, University Hospital Leipzig, Leipzig, Germany.,Department of Vascular Surgery, Krankenhausgesellschaft Sankt Vincenz GmbH, Limburg, Germany
| | - Volha Rusinovich
- Institute of Hygiene and Environmental Medicine, University Hospital Leipzig, Leipzig, Germany
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Burgos SA, Chevalier S, Morais JA, Lamarche M, Kellett S, Marliss EB. Acute hyperaminoacidemia does not suppress insulin-mediated glucose turnover in healthy young men. Appl Physiol Nutr Metab 2020; 46:397-403. [PMID: 33080141 DOI: 10.1139/apnm-2020-0495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Elevated circulating amino acids (AA) concentrations are purported to cause insulin resistance (IR) in humans. To quantify hyperaminoacidemia effects on insulin-mediated glucose turnover in healthy men, we performed 2-stage pancreatic clamps using octreotide with glucagon and growth hormone replacement. In the basal stage, insulin was infused to maintain euglycemia at postabsorptive levels. During the clamp stage, insulin was raised to postprandial levels, glycemia clamped at 5.5 mmol/L by glucose infusion, and branched-chain AA (BCAA) maintained at either postabsorptive (Hyper1; n = 8) or postprandial (Hyper2; n = 7) by AA infusion. Glucose turnover was measured by d-3-[3H]glucose dilution. Octreotide suppressed C-peptide; glucagon, growth hormone, and glycemia were maintained at postabsorptive levels throughout. Insulin did not differ at postabsorptive (72 ± 5 vs. 60 ± 5 pmol/L; Hyper1 vs. Hyper2) and increased to similar concentrations at basal (108 ± 11 vs. 106 ± 14) and clamp stages (551 ± 23 vs. 540 ± 25). Postabsorptive BCAA were maintained during Hyper1 and increased >2-fold (830 ± 26 µmol/L) during Hyper2. Endogenous glucose production was similarly suppressed (0.95 ± 0.16 vs. 1.37 ± 0.23 mg/kg lean body mass/min; Hyper1 vs. Hyper2) and basal glucose disposal (3.44 ± 0.12 vs. 3.67 ± 0.14) increased to similar levels (10.89 ± 0.56 vs. 11.11 ± 1.00) during the clamp. Thus, acute physiological elevation of AA for 3 h did not cause IR in healthy men. Novelty: A 2-step pancreatic clamp was used to quantify the effect of AA on insulin sensitivity in humans. Acute physiological elevation of circulating AA to postprandial levels does not cause IR in healthy men.
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Affiliation(s)
- Sergio A Burgos
- Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Medicine, McGill University, Montreal, QC H3G 1A4, Canada.,Metabolic Disorders and Complications Program, Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada
| | - Stéphanie Chevalier
- Department of Medicine, McGill University, Montreal, QC H3G 1A4, Canada.,Metabolic Disorders and Complications Program, Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada.,School of Human Nutrition, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - José A Morais
- Department of Medicine, McGill University, Montreal, QC H3G 1A4, Canada.,Metabolic Disorders and Complications Program, Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada.,School of Human Nutrition, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Marie Lamarche
- Metabolic Disorders and Complications Program, Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada
| | - Samantha Kellett
- Department of Medicine, McGill University, Montreal, QC H3G 1A4, Canada.,Metabolic Disorders and Complications Program, Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada
| | - Errol B Marliss
- Department of Medicine, McGill University, Montreal, QC H3G 1A4, Canada.,Metabolic Disorders and Complications Program, Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada
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5
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Deis T, Balling L, Rossing K, Boesgaard S, Kistorp CM, Wolsk E, Gøtze JP, Rehfeld JF, Gustafsson F. Plasma Somatostatin in Advanced Heart Failure: Association with Cardiac Filling Pressures and Outcome. Cardiology 2020; 145:769-778. [PMID: 33027795 DOI: 10.1159/000510284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 07/15/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Somatostatin inhibits intestinal motility and hormonal secretion and is a potent arterial vasoconstrictor of the splanchnic blood flow. It is unknown if somatostatin concentrations are associated with central hemodynamic measurements in patients with advanced heart failure (HF). METHODS A prospective study of HF patients with a left ventricular ejection fraction (LVEF) <45% referred to right heart catheterization (RHC) for evaluation for heart transplantation (HTX) or left ventricular assist device (LVAD). RESULTS Fifty-three patients were included with mean LVEF 18 ± 8% and majority in NYHA-class III-IV (79%). Median plasma somatostatin concentration was 18 pmol/L. In univariable regression analysis, log(somatostatin) was associated with increased central venous pressure (CVP; r2 = 0.14, p = 0.003) and a reduced cardiac index (CI; r2 = 0.15, p = 0.004). When adjusted for selected clinical variables (age, gender, LVEF, eGFR and BMI), log(somatostatin) remained a significant predictor of CVP (p = 0.044). Increased somatostatin concentrations predicted mortality in multivariable models (hazard ratio: 5.2 [1.2-22.2], p = 0.026) but not the combined endpoint of death, LVAD implantation or HTX. CONCLUSIONS Somatostatin concentrations were associated with CVP and CI in patients with HF. The pathophysiological mechanism may be related to congestion and/or hypoperfusion of the intestine. Somatostatin was an independent predictor of mortality in advanced HF.
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Affiliation(s)
- Tania Deis
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark,
| | - Louise Balling
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
| | - Kasper Rossing
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
| | - Søren Boesgaard
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
| | - Caroline Michaela Kistorp
- Department of Endocrinology, Rigshospitalet, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Emil Wolsk
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark
| | - Jens Peter Gøtze
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
| | | | - Finn Gustafsson
- Department of Cardiology, Rigshospitalet, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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6
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Schlader ZJ, Chapman CL, Benati JM, Gideon EA, Vargas NT, Lema PC, Johnson BD. Renal Hemodynamics During Sympathetic Activation Following Aerobic and Anaerobic Exercise. Front Physiol 2019; 9:1928. [PMID: 30687130 PMCID: PMC6335335 DOI: 10.3389/fphys.2018.01928] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 12/21/2018] [Indexed: 12/30/2022] Open
Abstract
We tested the hypotheses that prior aerobic (Study 1) or anaerobic (Study 2) exercise attenuates the increase in renal vascular resistance (RVR) during sympathetic stimulation. Ten healthy young adults (5 females) participated in both Study 1 (aerobic exercise) and Study 2 (anaerobic exercise). In Study 1, subjects completed three minutes of face cooling pre- and post- 30 min of moderate intensity aerobic exercise (68 ± 1% estimate maximal heart rate). In Study 2, subjects completed two minutes of the cold pressor test pre- and post- the completion of a 30 s maximal effort cycling test (Wingate Anaerobic Test). Both face cooling and the cold pressor test stimulate the sympathetic nervous system and elevate RVR. The primary dependent variable in both Studies was renal blood velocity, which was measured at baseline and every minute during sympathetic stimulation. Renal blood velocity was measured via the coronal approach at the distal segment of the right renal artery with pulsed wave Doppler ultrasound. RVR was calculated from the quotient of mean arterial pressure and renal blood velocity. In Study 1, renal blood velocity and RVR did not differ between pre- and post- aerobic exercise (P ≥ 0.24). Face cooling decreased renal blood velocity (P < 0.01) and the magnitude of this decrease did not differ between pre- and post- aerobic exercise (P = 0.52). RVR increased with face cooling (P < 0.01) and the extent of these increases did not differ between pre- and post- aerobic exercise (P = 0.74). In Study 2, renal blood velocity was 2 ± 2 cm/s lower post- anaerobic exercise (P = 0.02), but RVR did not differ (P = 0.08). The cold pressor test decreased renal blood velocity (P < 0.01) and the magnitude of this decrease did not differ between pre- and post- anaerobic exercise (P = 0.26). RVR increased with the cold pressor test (P < 0.01) and the extent of these increases did not differ between pre- and post- anaerobic exercise (P = 0.12). These data indicate that 30 min of moderate intensity aerobic exercise or 30 s of maximal effort anaerobic exercise does not affect the capacity to increase RVR during sympathetic stimulation following exercise.
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Affiliation(s)
- Zachary J. Schlader
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States
| | - Christopher L. Chapman
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States
| | - Julia M. Benati
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States
| | - Elizabeth A. Gideon
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States
| | - Nicole T. Vargas
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States
| | - Penelope C. Lema
- Department of Emergency Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Blair D. Johnson
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, United States
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7
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Shen WK, Sheldon RS, Benditt DG, Cohen MI, Forman DE, Goldberger ZD, Grubb BP, Hamdan MH, Krahn AD, Link MS, Olshansky B, Raj SR, Sandhu RK, Sorajja D, Sun BC, Yancy CW. 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation 2017; 136:e60-e122. [DOI: 10.1161/cir.0000000000000499] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Win-Kuang Shen
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | | | - David G. Benditt
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Mitchell I. Cohen
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Daniel E. Forman
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Zachary D. Goldberger
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Blair P. Grubb
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Mohamed H. Hamdan
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Andrew D. Krahn
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Mark S. Link
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Brian Olshansky
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Satish R. Raj
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Roopinder Kaur Sandhu
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Dan Sorajja
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Benjamin C. Sun
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Clyde W. Yancy
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
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9
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2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: Executive summary. Heart Rhythm 2017; 14:e218-e254. [DOI: 10.1016/j.hrthm.2017.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 01/05/2023]
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10
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Biaggioni I. The Pharmacology of Autonomic Failure: From Hypotension to Hypertension. Pharmacol Rev 2017; 69:53-62. [PMID: 28011746 DOI: 10.1124/pr.115.012161] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Primary neurodegenerative autonomic disorders are characterized clinically by loss of autonomic regulation of blood pressure. The clinical picture is dominated by orthostatic hypotension, but supine hypertension is also a significant problem. Autonomic failure can result from impairment of central autonomic pathways (multiple system atrophy) or neurodegeneration of peripheral postganglionic autonomic fibers (pure autonomic failure, Parkinson's disease). Pharmacologic probes such as the ganglionic blocker trimethaphan can help us in the understanding of the underlying pathophysiology and diagnosis of these disorders. Conversely, understanding the pathophysiology is crucial in the development of effective pharmacotherapy for these patients. Autonomic failure patients provide us with an unfortunate but unique research model characterized by loss of baroreflex buffering. This greatly magnifies the effect of stimuli that would not be apparent in normal subjects. An example of this is the discovery of the osmopressor reflex: ingestion of water increases blood pressure by 30-40 mm Hg in autonomic failure patients. Animal studies indicate that the trigger of this reflex is related to hypo-osmolality in the portal circulation involving transient receptor potential vanilloid 4 receptors. Studies in autonomic failure patients have also revealed that angiotensin II can be generated through noncanonical pathways independent of plasma renin activity to contribute to hypertension. Similarly, the mineralocorticoid receptor antagonist eplerenone produces acute hypotensive effects, highlighting the presence of non-nuclear mineralocorticoid receptor pathways. These are examples of careful clinical research that integrates pathophysiology and pharmacology to advance our knowledge of human disease.
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Affiliation(s)
- Italo Biaggioni
- Division of Clinical Pharmacology, Departments of Medicine and Pharmacology, Vanderbilt University, Nashville, Tennessee
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11
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Shen WK, Sheldon RS, Benditt DG, Cohen MI, Forman DE, Goldberger ZD, Grubb BP, Hamdan MH, Krahn AD, Link MS, Olshansky B, Raj SR, Sandhu RK, Sorajja D, Sun BC, Yancy CW. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Heart Rhythm 2017; 14:e155-e217. [PMID: 28286247 DOI: 10.1016/j.hrthm.2017.03.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 12/26/2022]
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12
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Shen WK, Sheldon RS, Benditt DG, Cohen MI, Forman DE, Goldberger ZD, Grubb BP, Hamdan MH, Krahn AD, Link MS, Olshansky B, Raj SR, Sandhu RK, Sorajja D, Sun BC, Yancy CW. 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2017; 70:620-663. [PMID: 28286222 DOI: 10.1016/j.jacc.2017.03.002] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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13
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Shen WK, Sheldon RS, Benditt DG, Cohen MI, Forman DE, Goldberger ZD, Grubb BP, Hamdan MH, Krahn AD, Link MS, Olshansky B, Raj SR, Sandhu RK, Sorajja D, Sun BC, Yancy CW. 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation 2017; 136:e25-e59. [PMID: 28280232 DOI: 10.1161/cir.0000000000000498] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Win-Kuang Shen
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | | | - David G Benditt
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Mitchell I Cohen
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Daniel E Forman
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Zachary D Goldberger
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Blair P Grubb
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Mohamed H Hamdan
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Andrew D Krahn
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Mark S Link
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Brian Olshansky
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Satish R Raj
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Roopinder Kaur Sandhu
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Dan Sorajja
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Benjamin C Sun
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
| | - Clyde W Yancy
- Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison.,Writing committee members are required to recuse themselves from voting on sections to which their specific relationships with industry may apply; see Appendix 1 for detailed information. ACC/AHA Task Force on Clinical Practice Guidelines Liaison. ACC/AHA Representative. HRS Representative. ACEP and SAEM Joint Representative. ACC/AHA Task Force on Performance Measures Liaison
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14
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Chevalier S, Burgos SA, Morais JA, Gougeon R, Bassil M, Lamarche M, Marliss EB. Protein and glucose metabolic responses to hyperinsulinemia, hyperglycemia, and hyperaminoacidemia in obese men. Obesity (Silver Spring) 2015; 23:351-8. [PMID: 25452199 DOI: 10.1002/oby.20943] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 09/29/2014] [Indexed: 12/28/2022]
Abstract
OBJECTIVE In insulin-resistant states, resistance of protein anabolism occurs concurrently with that of glucose, but can be compensated for by abundant amino acid (AA) provision. This effect and its mechanism were sought in obesity. METHODS Pancreatic clamps were performed in 8 lean and 11 obese men, following 5-h postabsorptive, 3-h infusions of octreotide, basal glucagon, and growth hormone, with clamped postprandial-level insulin, glucose, and AA. Whole-body [1-(13) C]-leucine and [3-(3) H]-glucose kinetics, skeletal muscle protein ((2) H5 -phenylalanine) fractional synthesis rates, and insulin signaling were determined. RESULTS Clamp Δ insulin and Δ branched-chain AA did not differ; fasting glucagon and growth hormone were maintained. Glucose uptake was 20% less in obese concurrent with less Akt(Ser473) , but also less IRS-1(Ser636/639) phosphorylation. Stimulation of whole-body, myofibrillar, and sarcoplasmic protein synthesis was similar. Whole-body protein catabolism suppression tended to be less (P=0.06), resulting in lesser net balance (1.09 ± 0.07 vs. 1.31 ± 0.08 μmol [kg FFM(-1) ] min(-1) , P=0.048). Increments in muscle S6K1(Thr389) phosphorylation were less in the obese, but 4E-BP1(Ser65) did not differ. CONCLUSIONS Hyperaminoacidemia with hyperinsulinemia stimulated protein synthesis (possibly via nutrient signaling) normally in obesity, but suppression of proteolysis may be compromised. Whether long-term high protein intakes could compensate for the insulin resistance of protein anabolism remains to be determined.
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Affiliation(s)
- Stéphanie Chevalier
- Crabtree Nutrition Laboratories, Department of Medicine, McGill University, and Research Institute of the McGill University Health Centre, Montreal, Quebec City, Canada
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15
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Circulatory responses to lower body negative pressure in young Afghans and Danes: implications for understanding ethnic effects on blood pressure regulation. Eur J Appl Physiol 2014; 114:2321-9. [PMID: 25059759 DOI: 10.1007/s00421-014-2946-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 06/25/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE We have previously shown that Afghans residing in Denmark for at least 12 years exhibit a lower 24-h ambulatory blood pressure compared to Danes. The purpose of this study was to test the hypothesis that the lower blood pressure reflects attenuated compensatory baroreflex responses in the Afghans. METHODS On a controlled diet (2,822 cal/day, 55-75 mmol + 2 mmol Na+/kg/day), 12 young males of Afghan (Afghans) and 12 young males of Danish (Danes) origin were exposed to a two-step lower body negative pressure (LBNP) protocol of -20 and -50 mmHg, respectively, each of 10-min duration. RESULTS Afghans had lower 24-h systolic blood pressure compared to Danes (115 ± 2 vs. 123 ± 1 mmHg, p < 0.05). Cardiac output and stroke volume were significantly lower in Afghans compared to Danes prior to and during each level of LBNP. However, it decreased to the same extent in both groups during LBNP. During LBNP of -20 mmHg, plasma noradrenaline concentration and plasma renin activity (PRA) increased significantly only in the Afghans. At LBNP of -50 mmHg plasma noradrenaline concentration and PRA both increased significantly and similarly in the two groups. CONCLUSION The lower 24-h ambulatory blood pressure in the Afghans is probably caused by a lower stroke volume, which augmented the circulatory and vasoactive hormonal responses to LBNP in the Afghans. The lower stroke volume in Afghans residing in Denmark compared to that of matched native Danes remains to be explained.
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16
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Jarvis SS, Shibata S, Okada Y, Levine BD, Fu Q. Neural-humoral responses during head-up tilt in healthy young white and black women. Front Physiol 2014; 5:86. [PMID: 24624092 PMCID: PMC3941214 DOI: 10.3389/fphys.2014.00086] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 02/13/2014] [Indexed: 11/13/2022] Open
Abstract
Young black women have higher prevalence of hypertension during pregnancy compared to white women, which may be attributable to differences in blood pressure (BP) regulation. We hypothesized that young normotensive black women would demonstrate augmented muscle sympathetic nerve activity (MSNA) and renal-adrenal responses to orthostasis. Fifteen white and ten black women (30 ± 4 vs. 32 ± 6 years; means ± SD) had haemodynamics and MSNA measured during baseline (BL), 30 and 60° head-up tilt (HUT), and recovery. Blood was drawn for catecholamines, direct renin, vasopressin, and aldosterone. BL brachial systolic BP (SBP: 107 ± 6 vs. 101 ± 9 mmHg) and diastolic BP (DBP: 62 ± 4 vs. 56 ± 7 mmHg) were higher in white women (both p < 0.05). Δ DBP (60° HUT-BL) was greater in black women compared to white (p < 0.05). Cardiac output and total peripheral resistance were similar between groups. MSNA burst frequency was higher in whites (BL: 16 ± 10 vs. 14 ± 9 bursts/min, main effect p < 0.05) and increased in both groups during HUT (60°: 39 ± 8 vs. 34 ± 13 bursts/min, p < 0.05 from BL). Noradrenaline was higher in white women during 60° HUT (60° HUT: 364 ± 102 vs. 267 ± 89 pg/ml, p < 0.05). Direct renin was higher and vasopressin and Δ aldosterone tended to be higher in blacks (BL, direct renin: 12.1 ± 5.0 vs. 14.4 ± 3.7 pg/ml, p < 0.05; BL, vasopressin: 0.4 ± 0.0 vs. 1.6 ± 3.6 pg/ml, p = 0.065; Δ aldosterone: −0.9 ± 5.1 vs. 3.8 ± 7.5 ng/ml; p = 0.069). These results suggest that young normotensive white women may rely on sympathetic neural activity more so than black women who have a tendency to rely on the renal-adrenal system to regulate BP during an orthostatic stress.
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Affiliation(s)
- Sara S Jarvis
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas Dallas, TX, USA ; Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA ; Department of Biological Sciences, Northern Arizona University Flagstaff, AZ, USA
| | - Shigeki Shibata
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas Dallas, TX, USA ; Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Yoshiyuki Okada
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas Dallas, TX, USA ; Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas Dallas, TX, USA ; Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas Dallas, TX, USA ; Department of Internal Medicine, University of Texas Southwestern Medical Center Dallas, TX, USA
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17
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Petersen LG, Carlsen JF, Nielsen MB, Damgaard M, Secher NH. The hydrostatic pressure indifference point underestimates orthostatic redistribution of blood in humans. J Appl Physiol (1985) 2014; 116:730-5. [PMID: 24481962 DOI: 10.1152/japplphysiol.01175.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The hydrostatic indifference point (HIP; where venous pressure is unaffected by posture) is located at the level of the diaphragm and is believed to indicate the orthostatic redistribution of blood, but it remains unknown whether HIP coincides with the indifference point for blood volume (VIP). During graded (± 20°) head-up (HUT) and head-down tilt (HDT) in 12 male volunteers, we determined HIP from central venous pressure and VIP from redistribution of both blood, using ultrasound imaging of the inferior caval vein (VIPui), and fluid volume, by regional electrical admittance (VIPadm). Furthermore, we evaluated whether inflation of medical antishock trousers (to 70 mmHg) affected HIP and VIP. Leaving cardiovascular variables unaffected by tilt, HIP was located 7 ± 4 cm (mean ± SD) below the 4th intercostal space (IC-4) during HUT and was similar (7 ± 3 cm) during HDT and higher (P < 0.0001) than both VIPui (HUT: 22 ± 16 cm; HDT: 13 ± 7 cm) and VIPadm (HUT: 29 ± 9 cm; HDT: 20 ± 9 cm below IC-4). During HUT antishock trousers elevated both HIP and VIPui [to 3 ± 5 cm (P = 0.028) and 17 ± 7 cm below IC-4 (P = 0.051), respectively], while VIPadm remained unaffected. By simultaneous recording of pressure and filling of the inferior caval vein as well as fluid distribution, we found HIP located corresponding to the diaphragm while VIP was placed low in the abdomen, and that medical antishock trousers elevated both HIP and VIP. The low indifference point for volume shows that the gravitational influence on distribution of blood is more profound than indicated by the indifference point for venous pressure.
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Affiliation(s)
- L G Petersen
- Department of Biomedical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
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18
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Blood pressure regulation X: what happens when the muscle pump is lost? Post-exercise hypotension and syncope. Eur J Appl Physiol 2013; 114:561-78. [PMID: 24197081 DOI: 10.1007/s00421-013-2761-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 10/22/2013] [Indexed: 01/19/2023]
Abstract
Syncope which occurs suddenly in the setting of recovery from exercise, known as post-exercise syncope, represents a failure of integrative physiology during recovery from exercise. We estimate that between 50 and 80% of healthy individuals will develop pre-syncopal signs and symptoms if subjected to a 15-min head-up tilt following exercise. Post-exercise syncope is most often neurally mediated syncope during recovery from exercise, with a combination of factors associated with post-exercise hypotension and loss of the muscle pump contributing to the onset of the event. One can consider the initiating reduction in blood pressure as the tip of the proverbial iceberg. What is needed is a clear model of what lies under the surface; a model that puts the observational variations in context and provides a rational framework for developing strategic physical or pharmacological countermeasures to ultimately protect cerebral perfusion and avert loss of consciousness. This review summarizes the current mechanistic understanding of post-exercise syncope and attempts to categorize the variation of the physiological processes that arise in multiple exercise settings. Newer investigations into the basic integrative physiology of recovery from exercise provide insight into the mechanisms and potential interventions that could be developed as countermeasures against post-exercise syncope. While physical counter maneuvers designed to engage the muscle pump and augment venous return are often found to be beneficial in preventing a significant drop in blood pressure after exercise, countermeasures that target the respiratory pump and pharmacological countermeasures based on the involvement of histamine receptors show promise.
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