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Suriany S, Liu H, Cheng AL, Wenby R, Patel N, Badran S, Meiselman HJ, Denton C, Coates TD, Wood JC, Detterich JA. Decreased erythrocyte aggregation in Glenn and Fontan: univentricular circulation as a rheologic disease model. Pediatr Res 2024; 95:1335-1345. [PMID: 38177250 DOI: 10.1038/s41390-023-02969-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 10/19/2023] [Accepted: 12/04/2023] [Indexed: 01/06/2024]
Abstract
BACKGROUND In the Fontan palliation for single ventricle heart disease (SVHD), pulmonary blood flow is non-pulsatile/passive, low velocity, and low shear, making viscous power loss a critical determinant of cardiac output. The rheologic properties of blood in SVHD patients are essential for understanding and modulating their limited cardiac output and they have not been systematically studied. We hypothesize that viscosity is decreased in single ventricle circulation. METHODS We evaluated whole blood viscosity, red blood cell (RBC) aggregation, and RBC deformability to evaluate changes in healthy children and SVHD patients. We altered suspending media to understand cellular and plasma differences contributing to rheologic differences. RESULTS Whole blood viscosity was similar between SVHD and healthy at their native hematocrits, while viscosity was lower at equivalent hematocrits for SVHD patients. RBC deformability is increased, and RBC aggregation is decreased in SVHD patients. Suspending SVHD RBCs in healthy plasma resulted in increased RBC aggregation and suspending healthy RBCs in SVHD plasma resulted in lower RBC aggregation. CONCLUSIONS Hematocrit corrected blood viscosity is lower in SVHD vs. healthy due to decreased RBC aggregation and higher RBC deformability, a viscous adaptation of blood in patients whose cardiac output is dependent on minimizing viscous power loss. IMPACT Patients with single ventricle circulation have decreased red blood cell aggregation and increased red blood cell deformability, both of which result in a decrease in blood viscosity across a large shear rate range. Since the unique Fontan circulation has very low-shear and low velocity flow in the pulmonary arteries, blood viscosity plays an increased role in vascular resistance, therefore this work is the first to describe a novel mechanism to target pulmonary vascular resistance as a modifiable risk factor. This is a novel, modifiable risk factor in this patient population.
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Affiliation(s)
- Silvie Suriany
- Division of Cardiology, Children's Hospital of Los Angeles, Los Angeles, CA, USA
| | - Honglei Liu
- Division of Cardiology, Children's Hospital of Los Angeles, Los Angeles, CA, USA
| | - Andrew L Cheng
- Division of Cardiology, Children's Hospital of Los Angeles, Los Angeles, CA, USA
| | - Rosalinda Wenby
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Neil Patel
- Division of Cardiology, Children's Hospital of Los Angeles, Los Angeles, CA, USA
| | - Sarah Badran
- Division of Pediatric and Congenital Cardiology, Helen Devos Children's Hospital at Spectrum Health, Grand Rapids, MI, USA
- Division of Cardiology, Department of Medicine, Michigan State University, East Lansing, MI, USA
| | - Herbert J Meiselman
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Christopher Denton
- Division of Hematology, Children's Hospital of Los Angeles, Los Angeles, CA, USA
| | - Thomas D Coates
- Division of Hematology, Children's Hospital of Los Angeles, Los Angeles, CA, USA
| | - John C Wood
- Division of Cardiology, Children's Hospital of Los Angeles, Los Angeles, CA, USA
| | - Jon A Detterich
- Division of Cardiology, Children's Hospital of Los Angeles, Los Angeles, CA, USA.
- Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
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Tariq UB. Comment on: Assessment of exercise capacity using field walking tests in patients after the Fontan procedure: A case-control study. Curr Probl Cardiol 2023:101792. [PMID: 37172865 DOI: 10.1016/j.cpcardiol.2023.101792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 05/07/2023] [Indexed: 05/15/2023]
Affiliation(s)
- Umer Bin Tariq
- Department of Medicine, Nawaz Sharif Medical College, University of Gujrat, Gujrat, Pakistan, Rawat, tehsil and district Islamabad, Pakistan.
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Hypoxia and hemorheological properties in older individuals. Ageing Res Rev 2022; 79:101650. [PMID: 35597435 DOI: 10.1016/j.arr.2022.101650] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/20/2022] [Accepted: 05/13/2022] [Indexed: 12/17/2022]
Abstract
Hypoxia is caused by insufficient oxygen availability for the organism leading to reduced oxygen delivery to tissues and cells. It has been regarded as a severe threat to human health and it is indeed implicated in pathophysiological mechanisms involved in the development and progression of many diseases. Nevertheless, the potential of controlled hypoxia interventions (i.e. hypoxia conditioning) for improving cardio-vascular health is gaining increased attention. However, blood rheology is often a forgotten factor for vascular health while aging and hypoxia exposure are both suspected to alter hemorheological properties. These changes in blood rheology may influence the benefits-risks balance of hypoxia exposure in older individuals. The benefits of hypoxia exposure for vascular health are mainly reported for healthy populations and the combined impact of aging and hypoxia on blood rheology could therefore be deleterious in older individuals. This review discusses evidence of hypoxia-related and aging-related changes in blood viscosity and its determinants. It draws upon an extensive literature search on the effects of hypoxia/altitude and aging on blood rheology. Aging increases blood viscosity mainly through a rise in plasma viscosity, red blood cell (RBC) aggregation and a decrease in RBC deformability. Hypoxia also causes an increase in RBC aggregation and plasma viscosity. In addition, hypoxia exposure may increase hematocrit and modulate RBC deformability, depending on the hypoxic dose, i.e, beneficial effect of intermittent hypoxia with moderate dose vs deleterious effect of chronic continuous or intermittent hypoxia or if the hypoxic dose is too high. Special attention is directed toward the risks vs. benefits of hemorheological changes during hypoxia exposure in older individuals, and its clinical relevance for vascular disorders.
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Quante H, Müller N, Härtel JA, Jung T, Manunzio U, Breuer J, Herberg U. Systemic ventricular function in Fontan patients at rest and after exercise at altitude. Front Pediatr 2022; 10:1084468. [PMID: 36683788 PMCID: PMC9853047 DOI: 10.3389/fped.2022.1084468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 12/13/2022] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVE Physical activity at high altitude is expected to pose risks for patients with Fontan circulation and to impair systemic ventricular function. This study aims to determine the effect of high-altitude hypoxia on ventricular function in Fontan patients at rest and after exercise. We hypothesize that systemic ventricular function deteriorates under hypoxic conditions in Fontan patients. METHODS In this prospective study, 21 Fontan patients (NYHA class I-II) and 21 age-, gender- and body mass index-matched healthy controls were enrolled (median age 17.9 and 16.9 years). Transthoracic echocardiography was performed at rest, after peak (PE) and after continuous exercise (CE) in normoxia and hypoxia at simulated altitude (2,500 m above sea level). The effect of hypoxia on echocardiographic parameters was quantified by linear mixed-effects models and the difference between normoxia and hypoxia (Δ= hypoxia-normoxia). RESULTS At rest, cardiac output (CO) estimated by outflow tract velocity time integral × heart rate and annular plane systolic excursion (APSE) were lower in hypoxia compared to normoxia in Fontan patients (CO: Δ = -12.0%, n.s.; APSE: Δ = -9.6%, p < 0.001), an increase was observed in controls (CO: Δ = 8.5%, n.s.; APSE: Δ = 2.5%, n.s.). Other parameters of systolic and diastolic function did not show relevant changes. After exercise under hypoxic conditions, Fontan patients did not show relevant deterioration of systolic function compared to normoxia. Late, active diastolic filling reflected by A-wave velocity remained unchanged in Fontan patients, but increased in controls. Under hypoxic conditions, CO and workload were higher after CE than PE in Fontan patients (CO: PE Δ = 1,530 vs. CE 1630), whereas controls showed higher work load and CO estimates after PE than CE as expected (CO: PE Δ = 2,302 vs. CE 2149). CONCLUSION Fontan patients clinically tolerated short-term altitude exposure up to two hours and exercise and showed no consistent deterioration of systolic systemic ventricular function, but parameters of myocardial contractility, heart rate and cardiac output did not increase as observed in controls. This is likely to be multifactorial and may include intrinsic cardiac dysfunction as well as preload inadequacy and the lack of augmented atrial contraction. CE may be better tolerated than PE.
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Affiliation(s)
- Hannah Quante
- Department of Pediatric Cardiology, University Hospital Bonn, Bonn, Germany
| | - Nicole Müller
- Department of Pediatric Cardiology, University Hospital Bonn, Bonn, Germany
| | | | - Thomas Jung
- Department of Pediatric Cardiology, University Hospital Bonn, Bonn, Germany
| | - Ursula Manunzio
- Department of Pediatric Cardiology, University Hospital Bonn, Bonn, Germany
| | - Johannes Breuer
- Department of Pediatric Cardiology, University Hospital Bonn, Bonn, Germany
| | - Ulrike Herberg
- Department of Pediatric Cardiology, University Hospital Bonn, Bonn, Germany
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