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Brener MI, Burkhoff D. Effect of nitroglycerin on splanchnic and pulmonary blood volume. J Nucl Cardiol 2022; 29:2964-2966. [PMID: 34935107 DOI: 10.1007/s12350-021-02877-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 11/12/2021] [Indexed: 01/18/2023]
Affiliation(s)
- Michael I Brener
- Division of Cardiology, Columbia University Medical Center, New York, NY, USA
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2
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Okamoto LE, Dupont WD, Biaggioni I, Kronenberg MW. Effect of nitroglycerin on splanchnic and pulmonary blood volume. J Nucl Cardiol 2022; 29:2952-2963. [PMID: 34729682 PMCID: PMC9590314 DOI: 10.1007/s12350-021-02811-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/02/2021] [Indexed: 01/22/2023]
Abstract
BACKGROUND Sublingual nitroglycerin (SL NTG) is useful for treating acute decompensated heart failure, possibly by increasing splanchnic capacitance and reducing left ventricular (LV) preload. We evaluated a radionuclide method to study these effects, initially in subjects without heart failure. METHODS AND RESULTS Red blood cells were labelled by an in vitro method. Abdominal and chest images were obtained at rest, showing relative regional blood volumes. The abdomen was then re-imaged during progressive escalation of intrathoracic pressure using continuous positive airway pressure to assess baseline splanchnic capacitance (pressure-volume relationship, PVR) and compliance (slope of PVR). The procedure was repeated after 0.6 mg SL NTG, followed by chest images. Relative splanchnic blood volume increased at rest after SL NTG (P < .002), signifying an increase in splanchnic capacitance. The slope of the splanchnic PVR decreased in proportion to the baseline PVR (P = .0014), signifying increased compliance. The relative pulmonary blood volume decreased in proportion to the increase in splanchnic blood volume (P = .01). CONCLUSIONS A semi-quantitative radionuclide method demonstrated the effect of SL NTG for increasing splanchnic capacitance and compliance, with a proportional decrease in pulmonary blood volume. These data may be applied to quantitatively evaluate the importance of splanchnic vasodilation as a mechanism of LV preload reduction in the treatment of heart failure. CLINICAL TRIALS REGISTRATION NCT02425566.
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Affiliation(s)
- Luis E Okamoto
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
- The Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - William D Dupont
- Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Italo Biaggioni
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
- The Vanderbilt Autonomic Dysfunction Center, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Marvin W Kronenberg
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Vanderbilt Heart and Vascular Institute, Vanderbilt Medical Center, East, Ste. 5209, 1215 21st. Ave, South, Nashville, TN, 37232, USA.
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Fudim M, Kaye DM, Borlaug BA, Shah SJ, Rich S, Kapur NK, Costanzo MR, Brener MI, Sunagawa K, Burkhoff D. Venous Tone and Stressed Blood Volume in Heart Failure: JACC Review Topic of the Week. J Am Coll Cardiol 2022; 79:1858-1869. [PMID: 35512865 PMCID: PMC9097251 DOI: 10.1016/j.jacc.2022.02.050] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/04/2022] [Accepted: 02/28/2022] [Indexed: 12/18/2022]
Abstract
A number of pathologic processes contribute to the elevation in cardiac filling pressures in heart failure (HF), including myocardial dysfunction and primary volume overload. In this review, we discuss the important role of the venous system and the concepts of stressed blood volume and unstressed blood volume. We review how regulation of venous tone modifies the distribution of blood between these 2 functional compartments, the physical distribution of blood between the pulmonary and systemic circulations, and how these relate to the hemodynamic abnormalities observed in HF. Finally, we review recently applied methods for estimating stressed blood volume and how they are being applied to the results of clinical studies to provide new insights into resting and exercise hemodynamics and therapeutics for HF.
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Affiliation(s)
- Marat Fudim
- Division of Cardiology, Department of Medicine, Duke University, Durham, North Carolina, USA; Duke Clinical Research Institute, Durham, North Carolina, USA.
| | - David M Kaye
- Department of Cardiology Alfred Hospital and Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | | | - Sanjiv J Shah
- Division of Cardiology, Northwestern University, Chicago, Illinois, USA
| | - Stuart Rich
- Division of Cardiology, Northwestern University, Chicago, Illinois, USA
| | - Navin K Kapur
- The CardioVascular Center, Tufts Medical Center, Boston, Massachusetts, USA. https://twitter.com/NavinKapur4
| | | | - Michael I Brener
- Columbia University, Division of Cardiology, New York, New York, USA. https://twitter.com/BrenerMickey
| | - Kenji Sunagawa
- Circulatory System Research Foundation, Hongo, Tokyo, Japan
| | - Daniel Burkhoff
- Cardiovascular Research Foundation, New York, New York, USA.
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4
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Fudim M, Ponikowski PP, Burkhoff D, Dunlap ME, Sobotka PA, Molinger J, Patel MR, Felker GM, Hernandez AF, Litwin SE, Borlaug BA, Bapna A, Sievert H, Reddy VY, Engelman ZJ, Shah SJ. Splanchnic nerve modulation in heart failure: mechanistic overview, initial clinical experience, and safety considerations. Eur J Heart Fail 2021; 23:1076-1084. [PMID: 33886137 PMCID: PMC8298285 DOI: 10.1002/ejhf.2196] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/23/2021] [Accepted: 04/18/2021] [Indexed: 12/20/2022] Open
Abstract
Volume recruitment from the splanchnic compartment is an important physiological response to stressors such as physical activity and blood loss. In the setting of heart failure (HF), excess fluid redistribution from this compartment leads to increased cardiac filling pressures with limitation in exercise capacity. Recent evidence suggests that blocking neural activity of the greater splanchnic nerve (GSN) could have significant benefits in some patients with HF by reducing cardiac filling pressures and improving exercise capacity. However, to date the long-term safety of splanchnic nerve modulation (SNM) in the setting of HF is unknown. SNM is currently used in clinical practice to alleviate some forms of chronic abdominal pain. A systematic review of the series where permanent SNM was used as a treatment for chronic abdominal pain indicates that permanent SNM is well tolerated, with side-effects limited to transient diarrhoea or abdominal colic and transient hypotension. The pathophysiological role of the GSN in volume redistribution, the encouraging findings of acute and chronic pilot SNM studies and the safety profile from permanent SNM for pain provides a strong basis for continued efforts to study this therapeutic target in HF.
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5
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Subclinical Volume Overload Across the Spectrum of Heart Failure: Lessons From Total Blood Volume Measurements. J Card Fail 2018; 24:425-427. [PMID: 29705258 DOI: 10.1016/j.cardfail.2018.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 04/23/2018] [Accepted: 04/23/2018] [Indexed: 02/04/2023]
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6
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Affiliation(s)
- Marat Fudim
- Division of Cardiology, Department of Internal Medicine, Duke University Hospital, Durham, NC
| | - Adrian F Hernandez
- Division of Cardiology, Department of Internal Medicine, Duke University Hospital, Durham, NC
- Duke Cardiovascular Research Institute, Durham, NC
| | - G Michael Felker
- Division of Cardiology, Department of Internal Medicine, Duke University Hospital, Durham, NC
- Duke Cardiovascular Research Institute, Durham, NC
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7
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Ormerod JOM, Arif S, Mukadam M, Evans JDW, Beadle R, Fernandez BO, Bonser RS, Feelisch M, Madhani M, Frenneaux MP. Short-term intravenous sodium nitrite infusion improves cardiac and pulmonary hemodynamics in heart failure patients. Circ Heart Fail 2015; 8:565-71. [PMID: 25838311 PMCID: PMC4435579 DOI: 10.1161/circheartfailure.114.001716] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 03/25/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Nitrite exhibits hypoxia-dependent vasodilator properties, selectively dilating capacitance vessels in healthy subjects. Unlike organic nitrates, it seems not to be subject to the development of tolerance. Currently, therapeutic options for decompensated heart failure (HF) are limited. We hypothesized that by preferentially dilating systemic capacitance and pulmonary resistance vessels although only marginally dilating resistance vessels, sodium nitrite (NaNO2) infusion would increase cardiac output but reduce systemic arterial blood pressure only modestly. We therefore undertook a first-in-human HF proof of concept/safety study, evaluating the hemodynamic effects of short-term NaNO2 infusion. METHODS AND RESULTS Twenty-five patients with severe chronic HF were recruited. Eight received short-term (5 minutes) intravenous NaNO2 at 10 μg/kg/min and 17 received 50 μg/kg/min with measurement of cardiac hemodynamics. During infusion of 50 μg/kg/min, left ventricular stroke volume increased (from 43.22±21.5 to 51.84±23.6 mL; P=0.003), with marked falls in pulmonary vascular resistance (by 29%; P=0.03) and right atrial pressure (by 40%; P=0.007), but with only modest falls in mean arterial blood pressure (by 4 mm Hg; P=0.004). The increase in stroke volume correlated with the increase in estimated trans-septal gradient (=pulmonary capillary wedge pressure-right atrial pressure; r=0.67; P=0.003), suggesting relief of diastolic ventricular interaction as a contributory mechanism. Directionally similar effects were observed for the above hemodynamic parameters with 10 μg/kg/min; this was significant only for stroke volume, not for other parameters. CONCLUSIONS This first-in-human HF efficacy/safety study demonstrates an attractive profile during short-term systemic NaNO2 infusion that may be beneficial in decompensated HF and warrants further evaluation with longer infusion regimens.
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Affiliation(s)
- Julian O M Ormerod
- From the Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (J.O.M.O., S.A., J.D.W.E., R.B., M.M.); Department of Cardiothoracic Surgery, Queen Elizabeth Hospital Birmingham NHS Trust, Birmingham, United Kingdom (M.M., R.S.B.); Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom (B.O.F., M.F.); and Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, United Kingdom (M.P.F.)
| | - Sayqa Arif
- From the Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (J.O.M.O., S.A., J.D.W.E., R.B., M.M.); Department of Cardiothoracic Surgery, Queen Elizabeth Hospital Birmingham NHS Trust, Birmingham, United Kingdom (M.M., R.S.B.); Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom (B.O.F., M.F.); and Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, United Kingdom (M.P.F.)
| | - Majid Mukadam
- From the Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (J.O.M.O., S.A., J.D.W.E., R.B., M.M.); Department of Cardiothoracic Surgery, Queen Elizabeth Hospital Birmingham NHS Trust, Birmingham, United Kingdom (M.M., R.S.B.); Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom (B.O.F., M.F.); and Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, United Kingdom (M.P.F.)
| | - Jonathan D W Evans
- From the Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (J.O.M.O., S.A., J.D.W.E., R.B., M.M.); Department of Cardiothoracic Surgery, Queen Elizabeth Hospital Birmingham NHS Trust, Birmingham, United Kingdom (M.M., R.S.B.); Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom (B.O.F., M.F.); and Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, United Kingdom (M.P.F.)
| | - Roger Beadle
- From the Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (J.O.M.O., S.A., J.D.W.E., R.B., M.M.); Department of Cardiothoracic Surgery, Queen Elizabeth Hospital Birmingham NHS Trust, Birmingham, United Kingdom (M.M., R.S.B.); Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom (B.O.F., M.F.); and Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, United Kingdom (M.P.F.)
| | - Bernadette O Fernandez
- From the Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (J.O.M.O., S.A., J.D.W.E., R.B., M.M.); Department of Cardiothoracic Surgery, Queen Elizabeth Hospital Birmingham NHS Trust, Birmingham, United Kingdom (M.M., R.S.B.); Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom (B.O.F., M.F.); and Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, United Kingdom (M.P.F.)
| | - Robert S Bonser
- From the Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (J.O.M.O., S.A., J.D.W.E., R.B., M.M.); Department of Cardiothoracic Surgery, Queen Elizabeth Hospital Birmingham NHS Trust, Birmingham, United Kingdom (M.M., R.S.B.); Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom (B.O.F., M.F.); and Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, United Kingdom (M.P.F.)
| | - Martin Feelisch
- From the Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (J.O.M.O., S.A., J.D.W.E., R.B., M.M.); Department of Cardiothoracic Surgery, Queen Elizabeth Hospital Birmingham NHS Trust, Birmingham, United Kingdom (M.M., R.S.B.); Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom (B.O.F., M.F.); and Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, United Kingdom (M.P.F.)
| | - Melanie Madhani
- From the Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (J.O.M.O., S.A., J.D.W.E., R.B., M.M.); Department of Cardiothoracic Surgery, Queen Elizabeth Hospital Birmingham NHS Trust, Birmingham, United Kingdom (M.M., R.S.B.); Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom (B.O.F., M.F.); and Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, United Kingdom (M.P.F.)
| | - Michael P Frenneaux
- From the Centre for Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (J.O.M.O., S.A., J.D.W.E., R.B., M.M.); Department of Cardiothoracic Surgery, Queen Elizabeth Hospital Birmingham NHS Trust, Birmingham, United Kingdom (M.M., R.S.B.); Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom (B.O.F., M.F.); and Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, United Kingdom (M.P.F.).
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8
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Chen X, Niu X, Xiao Y, Dong J, Lu M, Kong W. Effect of continuous positive airway pressure on leptin levels in patients with obstructive sleep apnea: a meta-analysis. Otolaryngol Head Neck Surg 2014; 152:610-8. [PMID: 25527507 DOI: 10.1177/0194599814562719] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 11/14/2014] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Continuous positive airway pressure (CPAP) is an effective treatment for obstructive sleep apnea hypopnea syndrome (OSAHS), but previous studies assessing the effect of CPAP on leptin in patients with OSAHS yielded conflicting results. In this study, we conducted a meta-analysis to determine whether CPAP therapy could reduce serum leptin levels. DATA SOURCES Databases of PubMed, Elsevier, and SCI were thoroughly searched by 2 independent reviewers. METHODS RevMan (version 5.2) was used for data synthesis. Weighted mean difference (WMD) before and after CPAP therapy was calculated to estimate the effects of CPAP therapy. RESULTS A total of 11 studies involving 413 participants were included. Meta-analysis showed that the total WMD for leptin levels was 1.44 units (95% confidence interval: 1.11-1.77, P < .01) before and after CPAP therapy. Subgroup analysis exhibited that leptin was decreased within 3 days after the therapy, and it was further reduced within 1 to 3 months and beyond. CONCLUSIONS The results of our meta-analysis showed that CPAP could significantly reduce leptin levels in OSAHS patients without concomitant weight loss.
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Affiliation(s)
- Xiong Chen
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Xun Niu
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Ying Xiao
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Jiaqi Dong
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Meixia Lu
- Department of Epidemiology and Biostatistics and the Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Weijia Kong
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
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9
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Maher AR, Arif S, Madhani M, Abozguia K, Ahmed I, Fernandez BO, Feelisch M, O'Sullivan AG, Christopoulos A, Sverdlov AL, Ngo D, Dautov R, James PE, Horowitz JD, Frenneaux MP. Impact of chronic congestive heart failure on pharmacokinetics and vasomotor effects of infused nitrite. Br J Pharmacol 2014; 169:659-70. [PMID: 23472879 DOI: 10.1111/bph.12152] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 11/29/2012] [Accepted: 02/03/2013] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND AND PURPOSE Nitrite (NO₂⁻) has recently been shown to represent a potential source of NO, in particular under hypoxic conditions. The aim of the current study was to compare the haemodynamic effects of NO₂⁻ in healthy volunteers and patients with stable congestive heart failure (CHF). EXPERIMENTAL APPROACH The acute haemodynamic effects of brachial artery infusion of NO₂⁻ (0.31 to 7.8 μmol·min⁻¹) was assessed in normal subjects (n = 20) and CHF patients (n = 21). KEY RESULTS NO₂⁻ infusion was well tolerated in all subjects. Forearm blood flow (FBF) increased markedly in CHF patients at NO₂⁻ infusion rates which induced no changes in normal subjects (ANOVA: F = 5.5; P = 0.02). Unstressed venous volume (UVV) increased even with the lowest NO₂⁻ infusion rate in all subjects (indicating venodilation), with CHF patients being relatively hyporesponsive compared with normal subjects (ANOVA: F = 6.2; P = 0.01). There were no differences in venous blood pH or oxygen concentration between groups or during NO₂⁻ infusion. Venous plasma NO₂⁻ concentrations were lower in CHF patients at baseline, and rose substantially less with NO₂⁻ infusion, without incremental oxidative generation of nitrate, consistent with accelerated clearance in these patients. Plasma protein-bound NO concentrations were lower in CHF patients than normal subjects at baseline. This difference was attenuated during NO₂⁻ infusion. Prolonged NO₂⁻ exposure in vivo did not induce oxidative stress, nor did it induce tolerance in vitro. CONCLUSIONS AND IMPLICATIONS The findings of arterial hyper-responsiveness to infused NO₂⁻ in CHF patients, with evidence of accelerated transvascular NO₂⁻ clearance (presumably with concomitant NO release) suggests that NO₂⁻ effects may be accentuated in such patients. These findings provide a stimulus for the clinical exploration of NO₂⁻ as a therapeutic modality in CHF.
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Affiliation(s)
- Abdul R Maher
- Centre for Cardiovascular Sciences, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
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10
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In search of euvolemia in heart failure. JACC-HEART FAILURE 2014; 2:306-7. [PMID: 24952699 DOI: 10.1016/j.jchf.2014.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 02/25/2014] [Indexed: 11/23/2022]
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11
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Li Y, Liu H, Gaskari SA, Tyberg JV, Lee SS. Altered mesenteric venous capacitance and volume pooling in cirrhotic rats are mediated by nitric oxide. Am J Physiol Gastrointest Liver Physiol 2008; 295:G252-9. [PMID: 18556420 DOI: 10.1152/ajpgi.00436.2007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In cirrhosis, despite augmented blood volume, effective circulating volume is decreased. This implies abnormal regulation of blood volume, i.e., venous pooling. Because gut veins are the main blood reservoir, we studied mesenteric venous capacitance and compliance in a rat model of cirrhosis. Cirrhosis was induced by bile duct ligation (4 wk). Controls were sham operated. Changes in first-order mesenteric vein diameters induced by drugs, hemorrhage, and stepwise increases in portal pressure (inflatable cuff) were directly observed by intravital microscopy. Effects of nitric oxide on responses to acute graded hemorrhage were studied by use of selective NO synthase (NOS) isoform inhibitors. Pressures were related to diameters to assess capacitance and compliance. Compared with controls, cirrhotic rats demonstrated increased mesenteric venous capacitance and decreased compliance. Norepinephrine induced venoconstriction but did not affect compliance. Prazosin markedly diminished compliance in controls but not cirrhotics. Conversely, the nonspecific NOS inhibitor N-nitro-l-arginine methyl ester (l-NAME) decreased compliance in cirrhotics, but not controls. Tetrodotoxin venodilated controls, venoconstricted cirrhotics, and markedly decreased compliance in both groups. When hemorrhaged, controls rapidly venoconstricted to compensate for initial hypotension, whereas cirrhotic rats remained hypotensive because venoconstriction was severely blunted. Pretreatment with l-NAME or the selective neuronal NOS inhibitors S-methyl-l-thiocitrulline and 7-nitroindazole normalized the homeostatic responses of cirrhotic rats, whereas the selective endothelial-constitutive NOS inhibitor N-iminoethyl-l-ornithine did not affect the response. In conclusion, mesenteric veins of cirrhotic rats showed enhanced capacitance, attenuated compensatory constrictive response to hemorrhage, and decreased compliance. The first two abnormalities were caused by neuronal NOS-derived nitric oxide.
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Affiliation(s)
- Yang Li
- Liver Unit, Gastrointestinal Research Group, Calgary, Alberta, Canada
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12
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Stewart JM, Montgomery LD. Reciprocal splanchnic-thoracic blood volume changes during the Valsalva maneuver. Am J Physiol Heart Circ Physiol 2004; 288:H752-8. [PMID: 15471975 PMCID: PMC4516268 DOI: 10.1152/ajpheart.00717.2004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Valsalva maneuver is frequently used to test autonomic function. Previous work demonstrated that the blood pressure decrease during the Valsalva maneuver relates to thoracic hypovolemia, which may preclude pressure recovery during phase II, even with normal resting peripheral vasoconstriction. We hypothesized that increased regional blood volume, specifically splanchnic hypervolemia, accounts for the degree of thoracic hypovolemia during the Valsalva maneuver. We studied 17 healthy volunteers aged 15-22 yr. All had normal blood volumes by dye dilution. Subjects also had normal vascular resistance while supine as well as normal vasoconstrictor responses during 35 degrees upright tilt. We assessed changes in estimated splanchnic, pelvic-thigh, and lower leg blood volume, along with thoracic blood volume shifts, by impedance plethysmography before and during the Valsalva maneuver performed in the supine position. Early increases in splanchnic blood volume dominated the regional vascular changes during the Valsalva maneuver. The increase in splanchnic blood volume correlated well (r2 = 0.65, P < 0.00001) with the decrease in thoracic blood volume, there was less correlation of the increase in pelvic blood volume (r2 = 0.21, P < 0.03), and there was no correlation of the increase in leg blood volume (r2 = 0.001, P = 0.9). There was no relation of thoracic hypovolemia with blood volume or peripheral resistance in supine or upright positions. Thoracic hypovolemia during the Valsalva maneuver is closely related to splanchnic hyperemia and weakly related to regional changes in blood volume elsewhere. Changes in baseline splanchnic vascular properties may account for variability in thoracic blood volume changes during the Valsalva maneuver.
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Affiliation(s)
- Julian M Stewart
- Department of Pediatrics, New York Medical College, Valhalla, New York 10595, USA.
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13
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Stewart JM, Medow MA, Bassett B, Montgomery LD. Effects of thoracic blood volume on Valsalva maneuver. Am J Physiol Heart Circ Physiol 2004; 287:H798-804. [PMID: 15059782 DOI: 10.1152/ajpheart.01174.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The Valsalva maneuver (VM) is frequently used to test autonomic function. However, the VM is also affected by changes in blood volume and blood volume redistribution. We hypothesized that even a standardized VM may produce a wide range of thoracic blood volume shifts. Larger blood volume shifts in some normovolemic individuals may be sufficient to induce decreases in blood pressure (BP) that preclude autonomic restoration of BP in phase II of the VM. To test this hypothesis, we studied 17 healthy volunteers aged 15-22 yr. All had similar vasoconstrictor responses when supine and upright and normal blood volume measurements. We assessed changes in thoracic blood volume by impedance plethysmography before and during the VM performed while subjects were supine. In some subjects, large decreases in BP were produced by thoracic hypovolemia. The maximum fractional decrease in BP correlated well (r(2) = 0.64; P < 0.001) with thoracic hypovolemia and with systolic BP at the end of phase II of the VM (r(2) = 0.67; P < 0.001). The BP overshoot in phase IV of the VM was uncorrelated to phase II changes, which suggests intact autonomic vasoconstriction. We conclude that the BP decrease during the VM is related to a variable decrease in thoracic blood volume that may be sufficient to preclude pressure recovery during phase II even with normal resting peripheral vasoconstriction. The VM depends on vascular as well as autonomic activation, which broadens its utility but complicates its analysis.
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Affiliation(s)
- Julian M Stewart
- Department of Pediatrics, New York Medical College, Valhalla, NY 10595, USA.
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14
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Schmitt M, Blackman DJ, Middleton GW, Cockcroft JR, Frenneaux MP. Assessment of venous capacitance. Radionuclide plethysmography: methodology and research applications. Br J Clin Pharmacol 2002; 54:565-76. [PMID: 12492602 PMCID: PMC1874491 DOI: 10.1046/j.1365-2125.2002.t01-7-01689.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Matthias Schmitt
- Department of Cardiology, Wales Heart Research Institute, University of Wales College of Medicine, Cardiff, UK.
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Abstract
The venous system contains approximately 70% of the blood volume. The sympathetic nervous system is by far the most important vasopressor system in the control of venous capacitance. The baroreflex system responds to acute hypotension by concurrently increasing sympathetic tone to resistance, as well as capacitance vessels, to increase blood pressure and venous return, respectively. Studies in experimental animals have shown that interference of sympathetic activity by an alpha1- or alpha2-adrenoceptor antagonist or a ganglionic blocker reduces mean circulatory filling pressure and venous resistance and increases unstressed volume. An alpha1- or alpha2-adrenoceptor agonist, on the other hand, increases mean circulatory filling pressure and venous resistance and reduces unstressed volume. In humans, drugs that interfere with sympathetic tone can cause the pooling of blood in limb as well as splanchnic veins; the reduction of cardiac output; and orthostatic intolerance. Other perturbations that can cause postural hypotension include autonomic failure, as in dysautonomia, diabetes mellitus, and vasovagal syncope; increased venous compliance, as in hemodialysis; and reduced blood volume, as with space flight and prolonged bed rest. Several alpha-adrenoceptor agonists are used to increase venous return in orthostatic intolerance; however, there is insufficient data to show that these drugs are more efficacious than placebo. Clearly, more basic science and clinical studies are needed to increase our knowledge and understanding of the venous system.
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Affiliation(s)
- C C Pang
- Department of Pharmacology and Therapeutics, Faculty of Medicine, The University of British Columbia, 2176 Health Sciences Mall, Vancouver, B.C. V6T 1Z3, Canada.
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16
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Tkacova R, Dajani HR, Rankin F, Fitzgerald FS, Floras JS, Douglas Bradley T. Continuous positive airway pressure improves nocturnal baroreflex sensitivity of patients with heart failure and obstructive sleep apnea. J Hypertens 2000; 18:1257-62. [PMID: 10994757 DOI: 10.1097/00004872-200018090-00012] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVES To determine the acute effects of continuous positive airway pressure (CPAP) on baroreceptor reflex sensitivity (BRS) for heart rate during sleep in congestive heart failure (CHF) patients with obstructive sleep apnea (OSA). DESIGN AND METHODS In eight CHF patients with OSA not previously treated with CPAP, spontaneous BRS was assessed during overnight polysomnography prior to the onset of sleep, and during stage 2 non-rapid eye movement sleep (NREM) before, during and after application of CPAP. RESULTS CPAP alleviated OSA and acutely increased the slope of BRS (median, 25%,75%) [from 3.9 (3.5, 4.8) to 6.2 (4.6, 26.2) ms/mmHg, P<0.05]. Increases in the slope of BRS persisted following withdrawal of CPAP [4.9 (4.3, 6.9) ms/mmHg, P<0.05]. CPAP also lowered heart rate (from 81.3 +/- 4.9 to 76.0 +/- 5.7 bpm, P< 0.05), an effect which persisted after its withdrawal (76.7 +/- 5.7 bpm, P < 0.05). Systolic blood pressure at the midpoint of the pressure range of BRS sequences fell while on CPAP (from 139 +/- 8 to 120 +/- 7 mmHg, P < 0.05), and remained lower following CPAP withdrawal (124 +/- 9 mmHg, P < 0.05). CONCLUSIONS In CHF patients with OSA, CPAP increases acutely BRS during sleep, lowers heart rate and resets the operating point for BRS to a lower blood pressure. These effects of CPAP persist after its withdrawal, suggesting that nocturnal CPAP therapy may cause sustained improvement in the neural control of heart rate.
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Affiliation(s)
- R Tkacova
- Sleep Research Laboratories of the Toronto Rehabilitation Institute, Ontario, Canada
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17
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Abstract
The venous system contains about 70% of the blood volume, and approximately 75% of the venous volume is in the small veins and venules. Veins play an active role in the control of cardiac output (CO) and blood pressure. Drugs that interfere with venous tone have profound effects on CO and blood pressure due to the large venous capacity. Information on body venous tone cannot be obtained from studies using isolated venous preparations and perfused venous beds, which lack modulating cardiovascular reflex mechanisms. In vivo methods used for the assessment of venous function in experimental animals and humans are as follows: the mean circulatory filling pressure (MCFP) method for the determination of body venous tone, constant CO reservoir technique for measuring vascular compliance and unstressed volume, plethysmography or blood-pool scintigraphy along with venous occlusion for measuring the volume and compliance of an organ, linear variable differential transformer (LVDT) technique for estimating the diameter of a human dorsal hand vein, intravascular ultrasound (IVUS) imaging technique to monitor the cross-sectional area of a large vein, and ultrasonic crystals to estimate the dimension of an organ. These methods are described and critically evaluated to disclose their validity, merits and limitations.
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Affiliation(s)
- C C Pang
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
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18
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Nussbacher A, Gerstenblith G, O'Connor FC, Becker LC, Kass DA, Schulman SP, Fleg JL, Lakatta EG. Hemodynamic effects of unloading the old heart. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H1863-71. [PMID: 10564141 DOI: 10.1152/ajpheart.1999.277.5.h1863] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A reduction in upright exercise capacity with aging in healthy individuals is accompanied by acute left ventricular (LV) dilatation and impaired LV ejection. To determine whether acute vasodilator administration would improve LV ejection during exercise, sodium nitroprusside (NP) was administered to 16 healthy subjects, ages 64-84 yr, who had been screened for the absence of coronary heart disease by prior exercise thallium scintigraphy. Infusion of NP (0. 3-1.0 microgram. kg(-1). min(-1)), titrated to reduce the resting mean arterial pressure 10% (and eliminate the late augmentation of carotid arterial pressure), increased LV ejection fraction (EF) compared with placebo during upright, maximal graded cycle exercise at all work rates and permitted an equivalent stroke volume and stroke work from a smaller end-diastolic volume. The maximum increase in exercise EF in older subjects during NP infusion was equal to that in healthy, younger (22-39 yr) control subjects. The maximum cycle work rate and cardiac index were unchanged compared with placebo. Thus combined preload and afterload reduction with NP in older individuals improves overall LV ejection phase function: exercise LV stroke work is reduced, EF is increased, and stroke volume is maintained in the setting of a reduced ventricular size. These findings suggest that at least some of the age-associated decline in cardiac function during maximal aerobic exercise may be secondary to adverse loading conditions.
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Affiliation(s)
- A Nussbacher
- Gerontology Research Center, National Institute on Aging, Baltimore, Maryland 21224, USA
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19
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Parameswaran N, Hamlin RL, Nakayama T, Rao SS. Increased Splenic Capacity in Response to Transdermal Application of Nitroglycerine in the Dog. J Vet Intern Med 1999. [DOI: 10.1111/j.1939-1676.1999.tb02164.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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20
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Ramaekers D, Ector H, Demyttenaere K, Rubens A, Van de Werf F. Association between cardiac autonomic function and coping style in healthy subjects. Pacing Clin Electrophysiol 1998; 21:1546-52. [PMID: 9725152 DOI: 10.1111/j.1540-8159.1998.tb00241.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The link between personality and cardiac function is insufficiently characterized. We postulated that in a healthy population, cardiac autonomic function is linked to coping style. In 276 healthy volunteers, between the ages of 18 and 71, the Utrecht Coping List was used to evaluate different coping strategies. Trait anxiety was scored by the Spielberger State Trait Anxiety Inventory. A 24-hour Holter recording was used to calculate heart rate variability (HRV). For HRV parameters and coping mechanisms this study demonstrated gender-specific differences and correlations with age. In men (n = 141) higher active coping was associated with less global autonomic activity or SDANN (rs = -0.27, P < 0.001). This relationship was most prevalent in young (18-30 years) men (rs = -0.45, P < 0.005). Higher expression of negative emotions or anger was related to both higher vagal (rs = 0.23 for rMSSD, P < 0.01) tone and higher LF power (rs = 0.23, P < 0.01). In young men expression of negative emotions or anger was associated with LF power (rs = 0.37, P < 0.01) and in middle-aged (31-50 years) men with vagal tone (rs = 0.43 for rMSSD, P < 0.005) and heart rate (rs = -0.41, P < 0.005). Higher comforting ideas was related to higher LF power (rs = 0.23 for LF power, P < 0.005), and this especially in middle-aged men (rs = 0.37, P < 0.01). In women (n = 135), no significant correlations between coping style and HRV indices were found. We conclude that in normal individuals, at least in men, our findings suggest a relationship between coping style and cardiac autonomic function.
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Affiliation(s)
- D Ramaekers
- Department of Cardiology, Gasthuisberg University Hospital, Catholic University of Leuven, Belgium
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21
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Abstract
OBJECTIVES To measure stressed vascular volume in humans and to review the concepts of stressed and unstressed vascular volume. DESIGN Observational study during surgical procedure. SETTING Operating room at a university hospital. PATIENTS Five patients undergoing hypothermic circulatory arrest for surgery on major vessels. INTERVENTION We measured the volume that drained from the patient to the reservoir of the pump when the pump was turned off. MEASUREMENTS AND MAIN RESULTS Stressed volume was 20.2+/-1.0 mL/kg, which is 30% of the predicted blood volume of these patients. CONCLUSION The amount of blood volume that determines vascular filling pressure is only about a quarter of the total predicted volume, which means that there is a large reserve of unstressed volume that can be recruited to maintain vascular filling pressure.
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Affiliation(s)
- S Magder
- Division of Critical Care, Royal Victoria Hospital, McGill University, Montréal, PQ, Canada
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23
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Bradley TD, Floras JS. Pathophysiologic and therapeutic implications of sleep apnea in congestive heart failure. J Card Fail 1996; 2:223-40. [PMID: 8891861 DOI: 10.1016/s1071-9164(96)80045-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Obstructive and central sleep apnea are common in patients with congestive heart failure (CHF). These sleep-related breathing disorders are characterized by two pathophysiologic features that could have important implications for disease progression in CHF: sympathetic nervous system activation, and adverse changes in cardiac loading conditions. In patients with obstructive sleep apnea, blood pressure is frequently elevated as a result of excessive sympathetic nervous system activity elicited by the combination of apnea, hypoxia, and arousals from sleep. The generation of exaggerated negative intrathoracic pressure during obstructive apneas further increases left ventricular afterload, reduces cardiac output, and may promote the progression of pump failure. Increased afterload and hypoxia can also predispose such patients to myocardial ischemia and arrhythmias. In patients with CHF, abolition of coexisting obstructive sleep apnea by nasal continuous positive airway pressure improves left ventricular function. Central sleep apnea (i.e., Cheyne-Stokes respiration) is also characterized by apnea, hypoxia, and increased sympathetic nervous system activity and, when present in CHF, is associated with increased risk of death. Recent medium-term trials involving small numbers of patients have demonstrated that nocturnally applied continuous positive airway pressure in patients with CHF and central sleep apnea alleviates central sleep apnea, improves left ventricular function, reduces sympathetic nervous system activity and improves symptoms of CHF. These studies emphasize the importance of considering obstructive and central sleep apnea in the differential diagnosis of conditions that could contribute to the development or progression of CHF. They also suggest that continuous positive airway pressure is a promising nonpharmacologic adjunctive therapy for patients with CHF and coexisting sleep-related breathing disturbances that warrants further investigation.
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Affiliation(s)
- T D Bradley
- Department of Medicine of the Toronto Hospital, Ontario, Canada
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