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Vejdani-Jahromi M, Freedman J, Trahey GE, Wolf PD. Measuring Intraventricular Pressure Using Ultrasound Elastography. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2019; 38:1167-1177. [PMID: 30218456 DOI: 10.1002/jum.14795] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 07/13/2018] [Accepted: 07/23/2018] [Indexed: 06/08/2023]
Abstract
OBJECTIVES Intraventricular pressure (IVP) is one of the most important measurements for evaluating cardiac function, but this measurement is not currently easily assessable in the clinic. The primary reason for this is the absence of a noninvasive technique for measuring IVP. In this study, we investigate the relationship between IVP and dynamic myocardial stiffness measured by shear wave elasticity imaging (SWEI) and assess the feasibility of measuring IVP using SWEI. METHODS In 8 isolated working rabbit hearts, IVP was recorded in the left ventricle using a pressure catheter. Simultaneously, myocardial stiffness was recorded by SWEI. Using the peak values for IVP and SWEI measured stiffness, SWEI measurements were calibrated and converted to IVP. RESULTS A linear relationship with zero intercept was observed between IVP and SWEI, with the average slope of 0.318 kPa/mm Hg, R2 = 0.89. Using one point on the IVP/SWEI curve, SWEI measurements were converted to IVP. Estimated pressure using SWEI and IVP were linearly correlated with the slope of 0.95, R2 = 0.88 (mean end diastolic pressure by pressure catheter = 12.716 mm Hg and by SWEI=14.726 mm Hg), indicating the near equivalence of the 2 measurements. CONCLUSION We have shown that SWEI measurements are linearly related to IVP; therefore, pressure-based indices could potentially be derived from SWEI ultrasound elastography. The feasibility of using SWEI to estimate IVP with a single point calibration was also shown in this study.
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Affiliation(s)
| | - Jenna Freedman
- Biomedical Engineering Department, Duke University, Durham, North Carolina, USA
| | - Gregg E Trahey
- Biomedical Engineering Department, Duke University, Durham, North Carolina, USA
| | - Patrick D Wolf
- Biomedical Engineering Department, Duke University, Durham, North Carolina, USA
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52
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Bauzá MDR, Giménez CS, Locatelli P, De Lorenzi A, Hnatiuk A, Capogrossi MC, Crottogini A, Cuniberti L, Olea FD. High-dose intramyocardial HMGB1 induces long-term cardioprotection in sheep with myocardial infarction. Drug Deliv Transl Res 2019; 9:935-944. [DOI: 10.1007/s13346-019-00628-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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53
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54
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Liu B, Hu X, Li Y, Ke J, Dasgupta C, Huang X, Walayat A, Zhang L, Xiao D. Epigenetic down-regulation of BK Ca channel by miR-181a contributes to the fetal and neonatal nicotine-mediated exaggerated coronary vascular tone in adult life. Int J Cardiol 2019; 281:82-89. [PMID: 30738609 DOI: 10.1016/j.ijcard.2019.01.099] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/07/2019] [Accepted: 01/29/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Fetal origin of adult cardiovascular disease is one of the most pressing public concerns and economic problem in modern life. Maternal cigarette smoking/nicotine abuse increases the risk of cardiovascular disease in offspring. However, the underlying mechanisms and theranostics remain unclear. We hypothesized that fetal and neonatal nicotine exposure enhances microRNA-181a (miR-181a) which targets large-conductance Ca2+-activated K+ (BKCa) channels, resulting in increased coronary vascular tone in adult offspring. METHODS Nicotine or saline was administered to pregnant rats via subcutaneous osmotic minipumps from gestational day 4 until postnatal day 10. Experiments were conducted in adult (~6 month old) male offspring. RESULTS Nicotine enhanced pressure-induced coronary vascular tone, which was abrogated by BKCa channel blocker. Nicotine selectively attenuated coronary BKCa β1 but not α subunit expression. Functionally, nicotine suppressed BKCa current density and inhibited BKCa activator NS1619-induced coronary relaxations. Furthermore, activation of BKCa increased coronary flow and improved heart ischemia/reperfusion-induced infarction. Nicotine selectively enhanced miR-181a expression. MiR-181a mimic inhibited BKCa β1 expression/channel current and decreased NS1619-induced coronary relaxation. Antioxidant eliminated the difference of BKCa current density between the saline and nicotine-treated groups and partially restored NS1619-induced relaxation in nicotine group. MiR-181a antisense decreased vascular tone and eliminated the differences between nicotine exposed and control groups. CONCLUSION Fetal and neonatal nicotine exposure-mediated miR-181a overexpression plays an important role in nicotine-enhanced coronary vascular tone via epigenetic down-regulation of BKca channel mechanism, which provides a potentially novel therapeutic molecular target of miR-181a/BKca channels for the treatment of coronary heart ischemic disease.
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Affiliation(s)
- Bailin Liu
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Xiangqun Hu
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Yong Li
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Jun Ke
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Chiranjib Dasgupta
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Xiaohui Huang
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Andrew Walayat
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Lubo Zhang
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Daliao Xiao
- Lawrence D. Longo, MD Center for Perinatal Biology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA.
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Alwan G, Manring ND, Emter CA, Delafontaine P, Leary E. Studying The Sensitivity Of Coronary Blood Flow Using Nondimensional Analysis. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:2349-2353. [PMID: 30440878 DOI: 10.1109/embc.2018.8512777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Nondimensional analysis was used to develop a novel model of coronary blood flow. In addition to general hemodynamics, the model was used to study the sensitivity of the arterial flow to variations in characteristic lumped parameters. Experimental hemodynamic data obtained from four normal healthy pigs were used in the current study. The results suggest that the mean coronary arterial flow is primarily sensitive to the flow and elasticity parameters of the coronary vasculature. Other flow features were also studied, and it was shown that the sensitivities of the general flow waveforms are influenced to different extents by the perturbations of these parameters. More specifically, the flow coefficient affects the systolic inflow more than the diastolic portion; conversely, the elasticity coefficient has more impact on the diastolic period.
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56
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Namani R, Kassab GS, Lanir Y. Morphometric Reconstruction of Coronary Vasculature Incorporating Uniformity of Flow Dispersion. Front Physiol 2018; 9:1069. [PMID: 30210353 PMCID: PMC6123366 DOI: 10.3389/fphys.2018.01069] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 07/17/2018] [Indexed: 01/22/2023] Open
Abstract
Experimental limitations in measurements of coronary flow in the beating heart have led to the development of in silico models of reconstructed coronary trees. Previous coronary reconstructions relied primarily on anatomical data, including statistical morphometry (e.g., diameters, length, connectivity, longitudinal position). Such reconstructions are non-unique, however, often leading to unrealistic predicted flow features. Thus, it is necessary to impose physiological flow constraints to ensure realistic tree reconstruction. Since a vessel flow depends on its diameter to fourth power, diameters are the logical candidates to guide vascular reconstructions to achieve realistic flows. Here, a diameter assignment method was developed where each vessel diameter was determined depending on its downstream tree size, aimed to reduce flow dispersion to within measured range. Since the coronary micro-vessels are responsible for a major portion of the flow resistance, the auto regulated coronary flow was analyzed in a morphometry-based reconstructed 400 vessel arterial microvascular sub-tree spanning vessel orders 1–6. Diameters in this subtree were re-assigned based on the flow criteria. The results revealed that diameter re-assignment, while adhering to measured morphometry, significantly reduced the flow dispersion to realistic levels while adhering to measured morphometry. The resulting network flow has longitudinal pressure distribution, flow fractal nature, and near-neighboring flow autocorrelation, which agree with measured coronary flow characteristics. Collectively, these results suggest that a realistic coronary tree reconstruction should impose not only morphometric data but also flow considerations. The work is of broad significance in providing a novel computational framework in the field of coronary microcirculation. It is essential for the study of coronary circulation by model simulation, based on a realistic network structure.
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Affiliation(s)
- Ravi Namani
- California Medical Innovations Institute Inc., San Diego, CA, United States.,Faculty of Biomedical Engineering, Technion, Haifa, Israel
| | - Ghassan S Kassab
- California Medical Innovations Institute Inc., San Diego, CA, United States
| | - Yoram Lanir
- Faculty of Biomedical Engineering, Technion, Haifa, Israel
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57
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Kiel AM, Goodwill AG, Baker HE, Dick GM, Tune JD. Local metabolic hypothesis is not sufficient to explain coronary autoregulatory behavior. Basic Res Cardiol 2018; 113:33. [PMID: 30073416 DOI: 10.1007/s00395-018-0691-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 06/19/2018] [Accepted: 07/04/2018] [Indexed: 01/21/2023]
Abstract
The local metabolic hypothesis proposes that myocardial oxygen tension determines the degree of autoregulation by increasing the production of vasodilator metabolites as perfusion pressure is reduced. Thus, normal physiologic levels of coronary venous PO2, an index of myocardial oxygenation, are proposed to be required for effective autoregulation. The present study challenged this hypothesis through determination of coronary responses to changes in coronary perfusion pressure (CPP 140-40 mmHg) in open-chest swine in the absence (n = 7) and presence of euvolemic hemodilution (~ 50% reduction in hematocrit), with (n = 5) and without (n = 6) infusion of dobutamine to augment MVO2. Coronary venous PO2 decreased over similar ranges (~ 28-15 mmHg) as CPP was lowered from 140 to 40 mmHg in each of the groups. However, coronary venous PO2 was not associated with changes in coronary blood flow (r = - 0.11; P = 0.29) or autoregulatory gain (r = - 0.29; P = 0.12). Coronary zero-flow pressure (Pzf) was measured in 20 mmHg increments and determined to be directly related to vascular resistance (r = 0.71; P < 0.001). Further analysis demonstrated that changes in coronary blood flow remained minimal at Pzf > 20 mmHg, but progressively increased as Pzf decreased below this threshold value (r = 0.68; P < 0.001). Coronary Pzf was also positively correlated with autoregulatory gain (r = 0.43; P = 0.001). These findings support that coronary autoregulatory behavior is predominantly dependent on an adequate degree of underlying vasomotor tone, independent of normal myocardial oxygen tension.
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Affiliation(s)
- Alexander M Kiel
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA.,Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Dr, West Lafayette, IN, 47907, USA
| | - Adam G Goodwill
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Hana E Baker
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA
| | - Gregory M Dick
- California Medical Innovations Institute, 11107 Roselle Street, San Diego, CA, 92121, USA
| | - Johnathan D Tune
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN, 46202, USA.
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58
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Auer J, Sharman JE, Weber T. J-curves in hypertension: what do they tell us about treatment of high blood pressure? Eur Heart J 2018; 39:3115-3118. [DOI: 10.1093/eurheartj/ehy337] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Johann Auer
- Department of Cardiology and Intensive Care, St Josef Hospital, Braunau, Austria
| | - James E Sharman
- Menzies Institute for Medical Research, University of Tasmania, Australia
| | - Thomas Weber
- Cardiology Department, Klinikum Wels-Grieskirchen, Wels, Austria
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Westerhof BE, Saouti N, van der Laarse WJ, Westerhof N, Vonk Noordegraaf A. Treatment strategies for the right heart in pulmonary hypertension. Cardiovasc Res 2018; 113:1465-1473. [PMID: 28957540 PMCID: PMC5852547 DOI: 10.1093/cvr/cvx148] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 09/01/2017] [Indexed: 02/06/2023] Open
Abstract
The function of the right ventricle (RV) determines the prognosis of patients with pulmonary hypertension. While much progress has been made in the treatment of pulmonary hypertension, therapies for the RV are less well established. In this review of treatment strategies for the RV, first we focus on ways to reduce wall stress since this is the main determinant of changes to the ventricle. Secondly, we discuss treatment strategies targeting the detrimental consequences of increased RV wall stress. To reduce wall stress, afterload reduction is the essential. Additionally, preload to the ventricle can be reduced by diuretics, by atrial septostomy, and potentially by mechanical ventricular support. Secondary to ventricular wall stress, left-to-right asynchrony, altered myocardial energy metabolism, and neurohumoral activation will occur. These may be targeted by optimising RV contraction with pacing, by iron supplement, by angiogenesis and improving mitochondrial function, and by neurohumoral modulation, respectively. We conclude that several treatment strategies for the right heart are available; however, evidence is still limited and further research is needed before clinical application can be recommended.
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Affiliation(s)
- Berend E Westerhof
- Department of Pulmonary Diseases, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.,Department of Medical Biology, Academic Medical Center, Amsterdam, The Netherlands
| | - Nabil Saouti
- Department of Cardio-Thoracic Surgery, St. Antonius Hospital, Nieuwegein, The Netherlands
| | - Willem J van der Laarse
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Nico Westerhof
- Department of Pulmonary Diseases, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
| | - Anton Vonk Noordegraaf
- Department of Pulmonary Diseases, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
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60
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Claridge S, Briceno N, Chen Z, De Silva K, Modi B, Jackson T, Behar JM, Niederer S, Rinaldi CA, Perera D. Changes in contractility determine coronary haemodynamics in dyssynchronous left ventricular heart failure, not vice versa. IJC HEART & VASCULATURE 2018; 19:8-13. [PMID: 29946557 PMCID: PMC6016072 DOI: 10.1016/j.ijcha.2018.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/07/2018] [Accepted: 03/11/2018] [Indexed: 01/09/2023]
Abstract
BACKGROUND Biventricular pacing has been shown to increase both cardiac contractility and coronary flow acutely but the causal relationship is unclear. We hypothesised that changes in coronary flow are secondary to changes in cardiac contractility. We sought to examine this relationship by modulating coronary flow and cardiac contractility. METHODS Contractility and lusitropy were altered by varying the location of pacing in 8 patients. Coronary autoregulation was transiently disabled with intracoronary adenosine. Simultaneous coronary flow velocity, coronary pressure and left ventricular pressure data were measured in the different pacing settings with and without hyperaemia and wave intensity analysis performed. RESULTS Multisite pacing was effective at altering left ventricular contractility and lusitropy (pos. dp/dtmax -13% to +10% and neg. dp/dtmax -15% to +17% compared to baseline). Intracoronary adenosine decreased microvascular resistance (362.5 mm Hg/s/m to 156.7 mm Hg/s/m, p < 0.001) and increased LAD flow velocity (22 cm/s vs 45 cm/s, p < 0.001) but did not acutely change contractility or lusitropy. The magnitude of the dominant accelerating wave, the Backward Expansion Wave, was proportional to the degree of contractility as well as lusitropy (r = 0.47, p < 0.01 and r = -0.50, p < 0.01). Perfusion efficiency (the proportion of accelerating waves) increased at hyperaemia (76% rest vs 81% hyperaemia, p = 0.04). Perfusion efficiency correlated with contractility and lusitropy at rest (r = 0.43 & -0.50 respectively, p = 0.01) and hyperaemia (r = 0.59 & -0.6, p < 0.01). CONCLUSIONS Acutely increasing coronary flow with adenosine in patients with systolic heart failure does not increase contractility. Changes in coronary flow with biventricular pacing are likely to be a consequence of enhanced cardiac contractility from resynchronization and not vice versa.
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Affiliation(s)
- Simon Claridge
- Department of Imaging Sciences, King's College, London, United Kingdom
| | - Natalia Briceno
- NIHR Biomedical Research Centre, School of Cardiovascular Medicine and Sciences, King's College London, United Kingdom
| | - Zhong Chen
- Department of Imaging Sciences, King's College, London, United Kingdom
| | - Kalpa De Silva
- NIHR Biomedical Research Centre, School of Cardiovascular Medicine and Sciences, King's College London, United Kingdom
| | - Bhavik Modi
- NIHR Biomedical Research Centre, School of Cardiovascular Medicine and Sciences, King's College London, United Kingdom
| | - Tom Jackson
- Department of Imaging Sciences, King's College, London, United Kingdom
| | - Jonathan M. Behar
- Department of Imaging Sciences, King's College, London, United Kingdom
| | - Steven Niederer
- Department of Imaging Sciences, King's College, London, United Kingdom
| | | | - Divaka Perera
- NIHR Biomedical Research Centre, School of Cardiovascular Medicine and Sciences, King's College London, United Kingdom
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61
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de Waard GA, Cook CM, van Royen N, Davies JE. Coronary autoregulation and assessment of stenosis severity without pharmacological vasodilation. Eur Heart J 2017; 39:4062-4071. [DOI: 10.1093/eurheartj/ehx669] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 11/20/2017] [Indexed: 01/10/2023] Open
Affiliation(s)
- Guus A de Waard
- Department of Cardiology, VU University Medical Center, de Boelelaan 1117, HV Amsterdam, The Netherlands
- National Heart and Lung Institute - Cardiovascular Science, Imperial College London, The Hammersmith Hospital, Du Cane Road, London, UK
| | - Christopher M Cook
- National Heart and Lung Institute - Cardiovascular Science, Imperial College London, The Hammersmith Hospital, Du Cane Road, London, UK
| | - Niels van Royen
- Department of Cardiology, VU University Medical Center, de Boelelaan 1117, HV Amsterdam, The Netherlands
- Department of Cardiology, Radboud University Medical Center, Geert Grooteplein Zuid 10, GA, Nijmegen, The Netherlands
| | - Justin E Davies
- National Heart and Lung Institute - Cardiovascular Science, Imperial College London, The Hammersmith Hospital, Du Cane Road, London, UK
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62
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Patra C, Boccaccini A, Engel F. Vascularisation for cardiac tissue engineering: the extracellular matrix. Thromb Haemost 2017; 113:532-47. [DOI: 10.1160/th14-05-0480] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 09/03/2014] [Indexed: 02/07/2023]
Abstract
SummaryCardiovascular diseases present a major socio-economic burden. One major problem underlying most cardiovascular and congenital heart diseases is the irreversible loss of contractile heart muscle cells, the cardiomyocytes. To reverse damage incurred by myocardial infarction or by surgical correction of cardiac malformations, the loss of cardiac tissue with a thickness of a few millimetres needs to be compensated. A promising approach to this issue is cardiac tissue engineering. In this review we focus on the problem of in vitro vascularisation as implantation of cardiac patches consisting of more than three layers of cardiomyocytes (> 100 μm thick) already results in necrosis. We explain the need for vascularisation and elaborate on the importance to include non-myocytes in order to generate functional vascularised cardiac tissue. We discuss the potential of extracellular matrix molecules in promoting vascularisation and introduce nephronectin as an example of a new promising candidate. Finally, we discuss current biomaterial- based approaches including micropatterning, electrospinning, 3D micro-manufacturing technology and porogens. Collectively, the current literature supports the notion that cardiac tissue engineering is a realistic option for future treatment of paediatric and adult patients with cardiac disease.
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63
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Toussaint J, Raval CB, Nguyen T, Fadaifard H, Joshi S, Wolberg G, Quarfordt S, Jan KM, Rumschitzki DS. Chronic hypertension increases aortic endothelial hydraulic conductivity by upregulating endothelial aquaporin-1 expression. Am J Physiol Heart Circ Physiol 2017; 313:H1063-H1073. [PMID: 28733452 PMCID: PMC5792199 DOI: 10.1152/ajpheart.00651.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 07/14/2017] [Accepted: 07/14/2017] [Indexed: 01/22/2023]
Abstract
Numerous studies have examined the role of aquaporins in osmotic water transport in various systems, but virtually none have focused on the role of aquaporin in hydrostatically driven water transport involving mammalian cells save for our laboratory's recent study of aortic endothelial cells. Here, we investigated aquaporin-1 expression and function in the aortic endothelium in two high-renin rat models of hypertension, the spontaneously hypertensive genetically altered Wistar-Kyoto rat variant and Sprague-Dawley rats made hypertensive by two-kidney, one-clip Goldblatt surgery. We measured aquaporin-1 expression in aortic endothelial cells from whole rat aortas by quantitative immunohistochemistry and function by measuring the pressure-driven hydraulic conductivities of excised rat aortas with both intact and denuded endothelia on the same vessel. We used them to calculate the effective intimal hydraulic conductivity, which is a combination of endothelial and subendothelial components. We observed well-correlated enhancements in aquaporin-1 expression and function in both hypertensive rat models as well as in aortas from normotensive rats whose expression was upregulated by 2 h of forskolin treatment. Upregulated aquaporin-1 expression and function may be a response to hypertension that critically determines conduit artery vessel wall viability and long-term susceptibility to atherosclerosis.NEW & NOTEWORTHY The aortic endothelia of two high-renin hypertensive rat models express greater than two times the aquaporin-1 and, at low pressures, have greater than two times the endothelial hydraulic conductivity of normotensive rats. Data are consistent with theory predicting that higher endothelial aquaporin-1 expression raises the critical pressure for subendothelial intima compression and for artery wall hydraulic conductivity to drop.
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Affiliation(s)
- Jimmy Toussaint
- 1Department of Chemical Engineering, City College of the City University of New York, New York, New York; ,4Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts;
| | - Chirag Bharavi Raval
- 1Department of Chemical Engineering, City College of the City University of New York, New York, New York; ,2Department of Biomedical Engineering, City College of the City University of New York, New York, New York;
| | - Tieuvi Nguyen
- 2Department of Biomedical Engineering, City College of the City University of New York, New York, New York;
| | - Hadi Fadaifard
- 3Department of Computer Science, City College of the City University of New York, New York, New York;
| | - Shripad Joshi
- 1Department of Chemical Engineering, City College of the City University of New York, New York, New York;
| | - George Wolberg
- 3Department of Computer Science, City College of the City University of New York, New York, New York;
| | - Steven Quarfordt
- 1Department of Chemical Engineering, City College of the City University of New York, New York, New York;
| | - Kung-ming Jan
- 5Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York; and
| | - David S. Rumschitzki
- 1Department of Chemical Engineering, City College of the City University of New York, New York, New York; ,5Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York; and ,6Biology (Molecular, Cellular, and Developmental Biology) and Chemistry (Biophysics) Departments, The Graduate School and University Center, City University of New York, New York, New York
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van der Velden J. Targeting High Oxygen Consumption to Prevent Cardiac Dysfunction in Patients With Aortic Valve Stenosis. Circ Cardiovasc Imaging 2017; 10:CIRCIMAGING.117.007015. [DOI: 10.1161/circimaging.117.007015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Jolanda van der Velden
- From the Department of Physiology, VU University Medical Center, Amsterdam Cardiovascular Sciences, The Netherlands
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65
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Penna C, Tullio F, Femminò S, Rocca C, Angelone T, Cerra MC, Gallo MP, Gesmundo I, Fanciulli A, Brizzi MF, Pagliaro P, Alloatti G, Granata R. Obestatin regulates cardiovascular function and promotes cardioprotection through the nitric oxide pathway. J Cell Mol Med 2017; 21:3670-3678. [PMID: 28744974 PMCID: PMC5706590 DOI: 10.1111/jcmm.13277] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/15/2017] [Indexed: 02/06/2023] Open
Abstract
Patients with ischaemic heart disease or chronic heart failure show altered levels of obestatin, suggesting a role for this peptide in human heart function. We have previously demonstrated that GH secretagogues and the ghrelin gene-derived peptides, including obestatin, exert cardiovascular effects by modulating cardiac inotropism and vascular tone, and reducing cell death and contractile dysfunction in hearts subjected to ischaemia/reperfusion (I/R), through the Akt/nitric oxide (NO) pathway. However, the mechanisms underlying the cardiac actions of obestatin remain largely unknown. Thus, we suggested that obestatin-induced activation of PI3K/Akt/NO and PKG signalling is implicated in protection of the myocardium when challenged by adrenergic, endothelinergic or I/R stress. We show that obestatin exerts an inhibitory tone on the performance of rat papillary muscle in both basal conditions and under β-adrenergic overstimulation, through endothelial-dependent NO/cGMP/PKG signalling. This pathway was also involved in the vasodilator effect of the peptide, used both alone and under stress induced by endothelin-1. Moreover, when infused during early reperfusion, obestatin reduced infarct size in isolated I/R rat hearts, through an NO/PKG pathway, comprising ROS/PKC signalling, and converging on mitochondrial ATP-sensitive potassium [mitoK(ATP)] channels. Overall, our results suggest that obestatin regulates cardiovascular function in stress conditions and induces cardioprotection by mechanisms dependent on activation of an NO/soluble guanylate cyclase (sGC)/PKG pathway. In fact, obestatin counteracts exaggerated β-adrenergic and endothelin-1 activity, relevant factors in heart failure, suggesting multiple positive effects of the peptide, including the lowering of cardiac afterload, thus representing a potential candidate in pharmacological post-conditioning.
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Affiliation(s)
- Claudia Penna
- Department of Clinical and Biological Sciences, University of Turin, Turin, Italy.,National Institute of Cardiovascular Research, Bologna, Italy
| | - Francesca Tullio
- Department of Clinical and Biological Sciences, University of Turin, Turin, Italy
| | - Saveria Femminò
- Department of Clinical and Biological Sciences, University of Turin, Turin, Italy
| | - Carmine Rocca
- National Institute of Cardiovascular Research, Bologna, Italy.,Department of Biology, Ecology and E.S., University of Calabria, Rende, CS, Italy
| | - Tommaso Angelone
- National Institute of Cardiovascular Research, Bologna, Italy.,Department of Biology, Ecology and E.S., University of Calabria, Rende, CS, Italy
| | - Maria C Cerra
- National Institute of Cardiovascular Research, Bologna, Italy.,Department of Biology, Ecology and E.S., University of Calabria, Rende, CS, Italy
| | - Maria Pia Gallo
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Iacopo Gesmundo
- Department of Medical Sciences, University of Turin, Turin, Italy
| | | | | | - Pasquale Pagliaro
- Department of Clinical and Biological Sciences, University of Turin, Turin, Italy.,National Institute of Cardiovascular Research, Bologna, Italy
| | - Giuseppe Alloatti
- National Institute of Cardiovascular Research, Bologna, Italy.,Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Riccarda Granata
- Department of Medical Sciences, University of Turin, Turin, Italy
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66
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van de Veerdonk MC, Huis In T Veld AE, Marcus JT, Westerhof N, Heymans MW, Bogaard HJ, Vonk-Noordegraaf A. Upfront combination therapy reduces right ventricular volumes in pulmonary arterial hypertension. Eur Respir J 2017; 49:49/6/1700007. [PMID: 28663315 DOI: 10.1183/13993003.00007-2017] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/11/2017] [Indexed: 11/05/2022]
Abstract
In pulmonary arterial hypertension (PAH), upfront combination therapy is associated with better clinical outcomes and a greater reduction in N-terminal pro-brain natriuretic peptide (NT-proBNP) than monotherapy. NT-proBNP levels reflect right ventricular (RV) wall stress, which increases when the right ventricle dilates. This study explored the impact of upfront combination therapy on RV volumes compared with monotherapy in PAH patients.This retrospective study involved 80 incident PAH patients (New York Heart Association class II and III) who were treated with upfront combination therapy (n=35) (i.e. endothelin receptor antagonists (ERAs) plus phosphodiesterase-5-inhibitors (PDE5Is)) or monotherapy (n=45) (i.e. either ERAs or PDE5Is). All patients underwent right-sided heart catheterisation and cardiac magnetic resonance imaging at baseline and after 1-year follow-up.Combination therapy resulted in more significant reductions in pulmonary vascular resistance and pulmonary pressures than monotherapy. NT-proBNP was decreased by ∼77% in the combination therapy group compared with a ∼51% reduction after monotherapy (p<0.001). RV volumes and calculated RV wall stress improved after combination therapy (both p<0.001) but remained unchanged after monotherapy (both p=NS). RV ejection fraction improved more in the combination therapy group than in the monotherapy group (p<0.001).In PAH patients, upfront combination therapy was associated with improved RV volumes.
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Affiliation(s)
- Mariëlle C van de Veerdonk
- Department of Pulmonary Diseases, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands.,Department of Cardiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands
| | - Anna E Huis In T Veld
- Department of Pulmonary Diseases, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands
| | - J Tim Marcus
- Department of Physics and Medical Technologies, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands
| | - Nico Westerhof
- Department of Pulmonary Diseases, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands
| | - Martijn W Heymans
- Department of Epidemiology and Biostatistics, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands
| | - Harm-Jan Bogaard
- Department of Pulmonary Diseases, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands
| | - Anton Vonk-Noordegraaf
- Department of Pulmonary Diseases, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands
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67
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Rose BA, Yokota T, Chintalgattu V, Ren S, Iruela-Arispe L, Khakoo AY, Minamisawa S, Wang Y. Cardiac myocyte p38α kinase regulates angiogenesis via myocyte-endothelial cell cross-talk during stress-induced remodeling in the heart. J Biol Chem 2017. [PMID: 28637870 DOI: 10.1074/jbc.m117.784553] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Stress-induced p38 mitogen-activated protein kinase (MAPK) activity is implicated in pathological remodeling in the heart. For example, constitutive p38 MAPK activation in cardiomyocytes induces pathological features, including myocyte hypertrophy, apoptosis, contractile dysfunction, and fetal gene expression. However, the physiological function of cardiomyocyte p38 MAPK activity in beneficial compensatory vascular remodeling is unclear. This report investigated the functional role and the underlying mechanisms of cardiomyocyte p38 MAPK activity in cardiac remodeling induced by chronic stress. Using both in vitro and in vivo model systems, we found that p38 MAPK activity is required for hypoxia-induced pro-angiogenic activity from cardiomyocytes and that p38 MAPK activation in cardiomyocyte is sufficient to promote paracrine signaling-mediated, pro-angiogenic activity. We further demonstrate that VEGF is a paracrine factor responsible for the p38 MAPK-mediated pro-angiogenic activity from cardiomyocytes and that p38 MAPK pathway activation is sufficient for inducing VEGF secretion from cardiomyocytes in an Sp1-dependent manner. More significantly, cardiomyocyte-specific inactivation of p38α in mouse heart impaired compensatory angiogenesis after pressure overload and promoted early onset of heart failure. In summary, p38αMAPK has a critical role in the cross-talk between cardiomyocytes and vasculature by regulating stress-induced VEGF expression and secretion in cardiomyocytes. We conclude that as part of a stress-induced signaling pathway, p38 MAPK activity significantly contributes to both pathological and compensatory remodeling in the heart.
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Affiliation(s)
- Beth A Rose
- Departments of Anesthesiology, Physiology, and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, California 90095
| | - Tomohiro Yokota
- Departments of Anesthesiology, Physiology, and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, California 90095; Department of Life Science and Medical Bioscience, Waseda University, 3-4-1 Okubo, Shinjuku-ku, 169-8555, Japan
| | | | - Shuxun Ren
- Departments of Anesthesiology, Physiology, and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, California 90095
| | - Luisa Iruela-Arispe
- Department of Molecular, Cellular, and Developmental Biology, Molecular Biology Institute, School of Life Sciences, University of California, Los Angeles, California 90095
| | - Aarif Y Khakoo
- Amgen, Inc., Metabolic Disorders, South San Francisco, California 94080
| | - Susumu Minamisawa
- Department of Life Science and Medical Bioscience, Waseda University, 3-4-1 Okubo, Shinjuku-ku, 169-8555, Japan; Department of Cell Physiology, Jikei University, 25-8, Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan
| | - Yibin Wang
- Departments of Anesthesiology, Physiology, and Medicine, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, California 90095.
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68
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Stoller M, Seiler C. Reactive myocardial hyperaemia for functional assessment of coronary stenosis severity. EUROINTERVENTION 2017; 13:e201-e209. [DOI: 10.4244/eij-d-16-00579] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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69
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Abstract
The heart is uniquely responsible for providing its own blood supply through the coronary circulation. Regulation of coronary blood flow is quite complex and, after over 100 years of dedicated research, is understood to be dictated through multiple mechanisms that include extravascular compressive forces (tissue pressure), coronary perfusion pressure, myogenic, local metabolic, endothelial as well as neural and hormonal influences. While each of these determinants can have profound influence over myocardial perfusion, largely through effects on end-effector ion channels, these mechanisms collectively modulate coronary vascular resistance and act to ensure that the myocardial requirements for oxygen and substrates are adequately provided by the coronary circulation. The purpose of this series of Comprehensive Physiology is to highlight current knowledge regarding the physiologic regulation of coronary blood flow, with emphasis on functional anatomy and the interplay between the physical and biological determinants of myocardial oxygen delivery. © 2017 American Physiological Society. Compr Physiol 7:321-382, 2017.
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Affiliation(s)
- Adam G Goodwill
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
| | - Gregory M Dick
- California Medical Innovations Institute, 872 Towne Center Drive, Pomona, CA
| | - Alexander M Kiel
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
- Weldon School of Biomedical Engineering, Purdue University, 206 S Martin Jischke Drive, Lafayette, IN
| | - Johnathan D Tune
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN
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70
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Busse H, Bitzinger D, Höcherl K, Seyfried T, Gruber M, Graf BM, Zausig YA. Adenosine A2A and A2B Receptor Substantially Attenuate Ischemia/Reperfusion Injury in Septic rat Hearts. Cardiovasc Drugs Ther 2017; 30:551-558. [PMID: 27757725 PMCID: PMC5156668 DOI: 10.1007/s10557-016-6693-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Introduction Mechanical and morphological ischemia and reperfusion (I/R) injury is reduced in septic hearts. The mechanism behind this “cardioprotection” is less well understood. As adenosine receptors play a major role for cardioprotection in non-septic hearts, we investigated the influence of adenosine receptors in a model of I/R in septic hearts. Methods SHAM operation or cecal ligation and puncture (CLP) was performed in adult male Wistar rats (n = 60). After 24 h of incubation, hearts were isolated and randomly assigned to a group with or without adenosine receptor (Ador) antagonists (SCH 58261 and MRS 1706) administered before reperfusion. Ischemia and reperfusion lasted for 40 min each. Cardiac function of the heart was determined by measuring left ventricular pressure (LVP). Results Before I/R, CLP hearts showed a significant mechanical left ventricular impairment (CLP: 63 ± 5 mmHg vs. SHAM: 104 ± 6 mmHg. After I/R, left ventricular function was significantly reduced in SHAM (24 ± 32 mmHg), but not in CLP hearts (65 ± 13 mmHg). mRNA expression for the AdorA2a and AdorA2b was significantly increased in CLP, but not in SHAM hearts. LVP of CLP hearts deteriorated when AdorA2a and AdorA2b were blocked. Conclusions The morphological and functional I/R injury in septic animals is less pronounced compared to non-septic animals. By a combined blockade of AdorA2a and AdorA2b this “cardioprotective” effect is nearly abolished in septic hearts. This is the first study showing, that AdorA2a and AdorA2b may play an important role for a reduced functional I/R injury in the septic heart.
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Affiliation(s)
- Hendrik Busse
- Department of Anesthesiology, University hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany.
| | - Diane Bitzinger
- Department of Anesthesiology, University hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Klaus Höcherl
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Timo Seyfried
- Department of Anesthesiology, University hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Michael Gruber
- Department of Anesthesiology, University hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - Bernhard M Graf
- Department of Anesthesiology, University hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
| | - York A Zausig
- Department of Anesthesiology, University hospital of Regensburg, Franz-Josef-Strauss-Allee 11, 93053, Regensburg, Germany
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71
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Bulte CS, Boer C, Hartemink KJ, Kamp O, Heymans MW, Loer SA, de Marchi SF, Vogel R, Bouwman RA. Myocardial Microvascular Responsiveness During Acute Cardiac Sympathectomy Induced by Thoracic Epidural Anesthesia. J Cardiothorac Vasc Anesth 2017; 31:134-141. [DOI: 10.1053/j.jvca.2016.05.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Indexed: 11/11/2022]
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72
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Bonde L, Shokouh P, Jeppesen PB, Boedtkjer E. Crosstalk between cardiomyocyte-rich perivascular tissue and coronary arteries is reduced in the Zucker Diabetic Fatty rat model of type 2 diabetes mellitus. Acta Physiol (Oxf) 2017; 219:227-238. [PMID: 27042951 DOI: 10.1111/apha.12685] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/30/2016] [Accepted: 03/31/2016] [Indexed: 12/20/2022]
Abstract
AIM We tested the hypothesis that crosstalk between cardiomyocyte-rich perivascular tissue (PVT) and coronary arteries is altered in diabetes. METHODS We studied the vasoactive effects of PVT in arteries from the Zucker Diabetic Fatty (ZDF) rat model of type 2 diabetes, streptozotocin (STZ)-treated Wistar rats with type 1 diabetes, and corresponding - heterozygous Zucker Lean (ZL) or vehicle-treated Wistar - control rats. Vasocontractile and vasorelaxant functions of coronary septal arteries with and without PVT were investigated using wire myography. RESULTS After careful removal of PVT, vasoconstriction in response to serotonin and thromboxane analogue U46619 was similar in arteries from ZDF and ZL rats, whereas depolarization-induced vasoconstriction - caused by elevating extracellular [K+ ] - was reduced in arteries from ZDF compared to ZL rats. PVT inhibited serotonin-, U46619- and depolarization-induced vasoconstriction in arteries from ZL rats, but this anticontractile influence of PVT was attenuated in arteries from ZDF rats. Methacholine-induced vasorelaxation was smaller in arteries from ZDF than ZL rats both with and without PVT, and the antirelaxant influence of PVT was comparable between arteries from ZDF and ZL rats. We observed no differences in vasoconstriction, vasorelaxation or PVT-dependent vasoactive effects between arteries from STZ- and vehicle-treated Wistar rats. CONCLUSION Anticontractile influences of PVT are attenuated in coronary arteries from ZDF rats but unaffected in arteries from STZ-treated rats. Signs of endothelial dysfunction are evident in coronary septal arteries - with and without PVT - from ZDF rats but not STZ-treated rats. We propose that altered signalling between cardiomyocyte-rich PVT and coronary arteries can contribute to cardiovascular complications in type 2 diabetes mellitus.
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Affiliation(s)
- L. Bonde
- Department of Biomedicine; Aarhus University; Aarhus Denmark
| | - P. Shokouh
- Department of Endocrinology and Diabetes; Department of Clinical Medicine; Aarhus University; Aarhus Denmark
- The Danish Diabetes Academy; Aarhus Denmark
| | - P. B. Jeppesen
- Department of Endocrinology and Internal Medicine; Aarhus University Hospital; Aarhus Denmark
| | - E. Boedtkjer
- Department of Biomedicine; Aarhus University; Aarhus Denmark
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73
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Wu H, Kassab GS, Tan W, Huo Y. Flow velocity is relatively uniform in the coronary sinusal venous tree: structure-function relation. J Appl Physiol (1985) 2017; 122:60-67. [PMID: 27789767 DOI: 10.1152/japplphysiol.00295.2016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 10/06/2016] [Accepted: 10/23/2016] [Indexed: 11/22/2022] Open
Abstract
The structure and function of coronary venous vessels are different from those of coronary arteries and are much less understood despite the therapeutic significance of coronary sinus interventions. Here we aimed to perform a hemodynamic analysis in the entire coronary sinusal venous tree, which enhances the understanding of coronary venous circulation. A hemodynamic model was developed in the entire coronary sinusal venous tree reconstructed from casts and histological data of five swine hearts. Various morphometric and hemodynamic parameters were determined in each vessel and analyzed in the diameter-defined Strahler system. The findings demonstrate an area preservation between the branches of the coronary venous system that leads to relatively uniform flow velocity in different orders of the venous tree. Pressure and circumferential and wall shear stresses decreased abruptly from the smallest venules toward vessels of order -5 (80.4 ± 39.1 µm) but showed a more modest change toward the coronary sinus. The results suggest that vessels of order -5 denote a hemodynamic transition from the venular bed to the transmural subnetwork. In contrast with the coronary arterial tree, which obeys the minimum energy hypothesis, the coronary sinusal venous system complies with the area-preserving rule for efficient venous return, i.e., da Vinci's rule. The morphometric and hemodynamic model serves as a physiological reference state to test various therapeutic rationales through the venous route. NEW & NOTEWORTHY A hemodynamic model is developed in the entire coronary sinusal venous tree of the swine heart. A key finding is that the coronary sinusal venous system complies with the area preservation rule for efficient venous return while the coronary arterial tree obeys the minimum energy hypothesis. This model can also serve as a physiological reference state to test various therapeutic rationales through the venous route.
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Affiliation(s)
- Hao Wu
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, People's Republic of China.,State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, People's Republic of China
| | | | - Wenchang Tan
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, People's Republic of China; .,State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, People's Republic of China.,Shenzhen Graduate School, Peking University, Shenzhen, People's Republic of China; and
| | - Yunlong Huo
- Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, People's Republic of China.,State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing, People's Republic of China.,College of Medicine, Hebei University, Baoding, People's Republic of China
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74
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Piola M, Vismara R, Tasca G, Lucherini F, Redaelli P, Soncini M, Romagnoni C, Mangini A, Antona C, Fiore GB. Design of a simple coronary impedance simulator for thein vitrostudy of the complex coronary hemodynamics. Physiol Meas 2016; 37:2274-2285. [DOI: 10.1088/1361-6579/37/12/2274] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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75
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Vejdani-Jahromi M, Freedman J, Nagle M, Kim YJ, Trahey GE, Wolf PD. Quantifying Myocardial Contractility Changes Using Ultrasound-Based Shear Wave Elastography. J Am Soc Echocardiogr 2016; 30:90-96. [PMID: 27843103 DOI: 10.1016/j.echo.2016.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Indexed: 01/06/2023]
Abstract
BACKGROUND Myocardial contractility, a significant determinant of cardiac function, is valuable for diagnosis and evaluation of treatment in cardiovascular disorders including heart failure. Shear wave elasticity imaging (SWEI) is a newly developed ultrasound-based elastographic technique that can directly assess the stiffness of cardiac tissue. The aim of this study was to verify the ability of this technique to quantify contractility changes in the myocardium. METHODS In 12 isolated rabbit hearts, SWEI measurements were made of systolic stiffness at five different coronary perfusion pressures from 0 to 92 mm Hg. The changes in coronary perfusion were used to induce acute stepwise reversible changes in cardiac contractility via the Gregg effect. The Gregg effect is the dependency of contractility on coronary perfusion. In four of the hearts, the measurements were repeated after delivery of gadolinium, which is known to block the Gregg effect. RESULTS Systolic stiffness measured by SWEI changed linearly with coronary perfusion pressure, with a slope of 0.27 kPa/mm Hg (mean of 95% CI, R2 = 0.73). As expected, the change in contractility due to the Gregg effect was blocked by gadolinium, with a significant reduction of the slope to 0.08 kPa/mm Hg. CONCLUSIONS SWEI measurements of systolic stiffness provide an index of contractility in the unloaded isolated rabbit heart. Although this study was done under ideal imaging conditions and with nonphysiologic loading conditions, it reinforces the concept that this ultrasound technique has the potential to provide a direct and noninvasive index of cardiac contractility.
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Affiliation(s)
| | - Jenna Freedman
- Biomedical Engineering Department, Duke University, Durham, North Carolina
| | - Matthew Nagle
- Biomedical Engineering Department, Duke University, Durham, North Carolina
| | - Young-Joong Kim
- Biomedical Engineering Department, Duke University, Durham, North Carolina
| | - Gregg E Trahey
- Biomedical Engineering Department, Duke University, Durham, North Carolina
| | - Patrick D Wolf
- Biomedical Engineering Department, Duke University, Durham, North Carolina.
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76
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Papadopoulos KP, Gavaises M, Pantos I, Katritsis DG, Mitroglou N. Derivation of flow related risk indices for stenosed left anterior descending coronary arteries with the use of computer simulations. Med Eng Phys 2016; 38:929-39. [DOI: 10.1016/j.medengphy.2016.05.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/15/2016] [Accepted: 05/26/2016] [Indexed: 10/21/2022]
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77
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Ladwiniec A, White PA, Nijjer SS, O’Sullivan M, West NE, Davies JE, Hoole SP. Diastolic Backward-Traveling Decompression (Suction) Wave Correlates With Simultaneously Acquired Indices of Diastolic Function and Is Reduced in Left Ventricular Stunning. Circ Cardiovasc Interv 2016; 9:CIRCINTERVENTIONS.116.003779. [DOI: 10.1161/circinterventions.116.003779] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 07/25/2016] [Indexed: 01/10/2023]
Abstract
Background—
Wave intensity analysis can distinguish proximal (propulsion) and distal (suction) influences on coronary blood flow and is purported to reflect myocardial performance and microvascular function. Quantifying the amplitude of the peak, backwards expansion wave (BEW) may have clinical utility. However, simultaneously acquired wave intensity analysis and left ventricular (LV) pressure–volume loop data, confirming the origin and effect of myocardial function on the BEW in humans, have not been previously reported.
Methods and Results—
Patients with single-vessel left anterior descending coronary disease and normal ventricular function (n=13) were recruited prospectively. We simultaneously measured LV function with a conductance catheter and derived wave intensity analysis using a pressure–low velocity guidewire at baseline and again 30 minutes after a 1-minute coronary balloon occlusion. The peak BEW correlated with the indices of diastolic LV function: LV dP/dt
min
(
r
s
=−0.59;
P
=0.002) and τ (
r
s
=−0.59;
P
=0.002), but not with systolic function. In 12 patients with paired measurements 30 minutes post balloon occlusion, LV dP/dt
max
decreased from 1437.1±163.9 to 1299.4±152.9 mm Hg/s (median difference, −110.4 [−183.3 to −70.4];
P
=0.015) and τ increased from 48.3±7.4 to 52.4±7.9 ms (difference, 4.1 [1.3–6.9];
P
=0.01), but basal average peak coronary flow velocity was unchanged, indicating LV stunning post balloon occlusion. However, the peak BEW amplitude decreased from −9.95±5.45 W·m
–2
/s
2
×10
5
to −7.52±5.00 W·m
–2
/s
2
×10
5
(difference 2.43×10
5
[0.20×10
5
to 4.67×10
5
;
P
=0.04]).
Conclusions—
Peak BEW assessed by coronary wave intensity analysis correlates with invasive indices of LV diastolic function and mirrors changes in LV diastolic function confirming the origin of the suction wave. This may have implications for physiological lesion assessment after percutaneous coronary intervention.
Clinical Trial Registration—
URL:
http://www.isrctn.org
. Unique identifier: ISRCTN42864201.
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Affiliation(s)
- Andrew Ladwiniec
- From the Department of Cardiology, Papworth Hospital, Cambridge, United Kingdom (A.L., M.O., N.E.J.W., S.P.H.); Department of Medical Physics and Clinical Engineering, Addenbrooke’s Hospital, Cambridge, United Kingdom (P.A.W.); and International Centre for Circulatory Health, Imperial College, London, United Kingdom (S.S.N., J.E.D.)
| | - Paul A. White
- From the Department of Cardiology, Papworth Hospital, Cambridge, United Kingdom (A.L., M.O., N.E.J.W., S.P.H.); Department of Medical Physics and Clinical Engineering, Addenbrooke’s Hospital, Cambridge, United Kingdom (P.A.W.); and International Centre for Circulatory Health, Imperial College, London, United Kingdom (S.S.N., J.E.D.)
| | - Sukhjinder S. Nijjer
- From the Department of Cardiology, Papworth Hospital, Cambridge, United Kingdom (A.L., M.O., N.E.J.W., S.P.H.); Department of Medical Physics and Clinical Engineering, Addenbrooke’s Hospital, Cambridge, United Kingdom (P.A.W.); and International Centre for Circulatory Health, Imperial College, London, United Kingdom (S.S.N., J.E.D.)
| | - Michael O’Sullivan
- From the Department of Cardiology, Papworth Hospital, Cambridge, United Kingdom (A.L., M.O., N.E.J.W., S.P.H.); Department of Medical Physics and Clinical Engineering, Addenbrooke’s Hospital, Cambridge, United Kingdom (P.A.W.); and International Centre for Circulatory Health, Imperial College, London, United Kingdom (S.S.N., J.E.D.)
| | - Nick E.J. West
- From the Department of Cardiology, Papworth Hospital, Cambridge, United Kingdom (A.L., M.O., N.E.J.W., S.P.H.); Department of Medical Physics and Clinical Engineering, Addenbrooke’s Hospital, Cambridge, United Kingdom (P.A.W.); and International Centre for Circulatory Health, Imperial College, London, United Kingdom (S.S.N., J.E.D.)
| | - Justin E. Davies
- From the Department of Cardiology, Papworth Hospital, Cambridge, United Kingdom (A.L., M.O., N.E.J.W., S.P.H.); Department of Medical Physics and Clinical Engineering, Addenbrooke’s Hospital, Cambridge, United Kingdom (P.A.W.); and International Centre for Circulatory Health, Imperial College, London, United Kingdom (S.S.N., J.E.D.)
| | - Stephen P. Hoole
- From the Department of Cardiology, Papworth Hospital, Cambridge, United Kingdom (A.L., M.O., N.E.J.W., S.P.H.); Department of Medical Physics and Clinical Engineering, Addenbrooke’s Hospital, Cambridge, United Kingdom (P.A.W.); and International Centre for Circulatory Health, Imperial College, London, United Kingdom (S.S.N., J.E.D.)
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78
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Weber T, Lang I, Zweiker R, Horn S, Wenzel RR, Watschinger B, Slany J, Eber B, Roithinger FX, Metzler B. Hypertension and coronary artery disease: epidemiology, physiology, effects of treatment, and recommendations : A joint scientific statement from the Austrian Society of Cardiology and the Austrian Society of Hypertension. Wien Klin Wochenschr 2016; 128:467-79. [PMID: 27278135 DOI: 10.1007/s00508-016-0998-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/15/2016] [Indexed: 01/13/2023]
Abstract
High blood pressure is a major modifiable risk factor for all clinical manifestations of coronary artery disease (CAD). In people without known cardiovascular disease, the lowest systolic (down to 90-114 mmHg) and the lowest diastolic (down to 60-74 mmHg) pressures are associated with the lowest risk for developing CAD. Although diastolic blood pressure is the strongest predictor of CAD in younger and middle-aged people, this relationship becomes inverted and pulse pressure shows the strongest direct relationship with CAD in people above 60 years of age.Pathophysiological mechanisms of blood pressure as a risk factor for CAD are complex and include the influence of blood pressure as a physical force on the development of the atherosclerotic plaque, and the relationship between pulsatile hemodynamics/arterial stiffness and coronary perfusion. Treatment of arterial hypertension has been proven to prevent coronary events in patients without clinical CAD. In patients with established CAD, the effect of blood pressure lowering per se is beneficial, probably more than specific drugs or drug classes. The important exceptions are beta blockers (BBs), which are superior to all other drug classes for use after a recent myocardial infarction. Blood pressure targets in patients with established CAD have created controversy in the light of the so-called J-curve phenomenon, which describes an increase in coronary events at lower diastolic blood pressures. One explanation for this observation is that perfusion of the left ventricle occurs predominantly during diastole, and that coronary autoregulation may be exhausted with low diastolic blood pressure in the setting of left ventricular hypertrophy and atherosclerotic narrowing of the epicardial coronaries. The worst situation is a high systolic blood pressure in the presence of a low diastolic blood pressure, both a hallmark of increased aortic stiffness. However, the lowering of systolic blood pressure is clearly beneficial in this setting, even at the price of further lowering diastolic pressure. Primary blood pressure goal in patients with established CAD is below 140/90 mmHg. Recent studies suggest that a lower systolic blood pressure may be appropriate, whereas caution is advised with diastolic blood pressure below 60 mmHg.
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Affiliation(s)
- Thomas Weber
- Cardiology Department, Klinikum Wels-Grieskirchen, Grieskirchnerstraße 42, 4600, Wels, Austria.
| | - Irene Lang
- Division of Cardiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria
| | - Robert Zweiker
- Division of Cardiology, Department of Internal Medicine, Medical University Graz, Graz, Austria
| | - Sabine Horn
- Division of Nephrology, Department of Internal Medicine, Medical University Graz, Graz, Austria
| | - Rene R Wenzel
- Department of Internal Medicine, Krankenhaus Tauernkliniken, Zell am See, Austria
| | - Bruno Watschinger
- Division of Nephrology, Department of Internal Medicine III, Medical University Vienna, Vienna, Austria
| | | | - Bernd Eber
- Cardiology Department, Klinikum Wels-Grieskirchen, Grieskirchnerstraße 42, 4600, Wels, Austria
| | - Franz Xaver Roithinger
- Second Department of Internal Medicine, Landesklinikum Wiener Neustadt, Vienna, Austria
- Internal Department, Landesklinikum Mödling, Mödling, Austria
| | - Bernhard Metzler
- Department of Internal Medicine III, Medical University Innsbruck, Innsbruck, Austria
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79
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Arthurs CJ, Lau KD, Asrress KN, Redwood SR, Figueroa CA. A mathematical model of coronary blood flow control: simulation of patient-specific three-dimensional hemodynamics during exercise. Am J Physiol Heart Circ Physiol 2016; 310:H1242-58. [PMID: 26945076 PMCID: PMC4867386 DOI: 10.1152/ajpheart.00517.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 03/01/2016] [Indexed: 01/07/2023]
Abstract
This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input. The model can be used in zero-dimensional lumped parameter network studies or as a boundary condition for three-dimensional multidomain Navier-Stokes blood flow simulations. For the first time, this model provides feedback control of the coronary vascular resistance, which can be used to enhance the physiological accuracy of any hemodynamic simulation, which includes both a heart model and coronary arteries. This has particular relevance to patient-specific simulation for which heart rate and aortic pressure recordings are available. In addition to providing a simulation tool, under our assumptions, the derivation of our model shows that β-feedforward control of the coronary microvascular resistance is a mathematical necessity and that the metabolic feedback control must be dependent on two error signals: the historical myocardial oxygen debt, and the instantaneous myocardial oxygen deficit.
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Affiliation(s)
- Christopher J Arthurs
- Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London, United Kingdom;
| | - Kevin D Lau
- Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London, United Kingdom; Departments of Surgery and Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
| | - Kaleab N Asrress
- King's College London British Heart Foundation Centre of Excellence, The Rayne Institute, St. Thomas' Hospital Campus, London, United Kingdom; and
| | - Simon R Redwood
- King's College London British Heart Foundation Centre of Excellence, The Rayne Institute, St. Thomas' Hospital Campus, London, United Kingdom; and
| | - C Alberto Figueroa
- Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London, United Kingdom; Departments of Surgery and Biomedical Engineering, University of Michigan, Ann Arbor, Michigan
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80
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Chabiniok R, Wang VY, Hadjicharalambous M, Asner L, Lee J, Sermesant M, Kuhl E, Young AA, Moireau P, Nash MP, Chapelle D, Nordsletten DA. Multiphysics and multiscale modelling, data-model fusion and integration of organ physiology in the clinic: ventricular cardiac mechanics. Interface Focus 2016; 6:20150083. [PMID: 27051509 PMCID: PMC4759748 DOI: 10.1098/rsfs.2015.0083] [Citation(s) in RCA: 139] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
With heart and cardiovascular diseases continually challenging healthcare systems worldwide, translating basic research on cardiac (patho)physiology into clinical care is essential. Exacerbating this already extensive challenge is the complexity of the heart, relying on its hierarchical structure and function to maintain cardiovascular flow. Computational modelling has been proposed and actively pursued as a tool for accelerating research and translation. Allowing exploration of the relationships between physics, multiscale mechanisms and function, computational modelling provides a platform for improving our understanding of the heart. Further integration of experimental and clinical data through data assimilation and parameter estimation techniques is bringing computational models closer to use in routine clinical practice. This article reviews developments in computational cardiac modelling and how their integration with medical imaging data is providing new pathways for translational cardiac modelling.
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Affiliation(s)
- Radomir Chabiniok
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas’ Hospital, London SE1 7EH, UK
- Inria and Paris-Saclay University, Bâtiment Alan Turing, 1 rue Honoré d'Estienne d'Orves, Campus de l'Ecole Polytechnique, Palaiseau 91120, France
| | - Vicky Y. Wang
- Auckland Bioengineering Institute, University of Auckland, 70 Symonds Street, Auckland, New Zealand
| | - Myrianthi Hadjicharalambous
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas’ Hospital, London SE1 7EH, UK
| | - Liya Asner
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas’ Hospital, London SE1 7EH, UK
| | - Jack Lee
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas’ Hospital, London SE1 7EH, UK
| | - Maxime Sermesant
- Inria, Asclepios team, 2004 route des Lucioles BP 93, Sophia Antipolis Cedex 06902, France
| | - Ellen Kuhl
- Departments of Mechanical Engineering, Bioengineering, and Cardiothoracic Surgery, Stanford University, 496 Lomita Mall, Durand 217, Stanford, CA 94306, USA
| | - Alistair A. Young
- Auckland Bioengineering Institute, University of Auckland, 70 Symonds Street, Auckland, New Zealand
| | - Philippe Moireau
- Inria and Paris-Saclay University, Bâtiment Alan Turing, 1 rue Honoré d'Estienne d'Orves, Campus de l'Ecole Polytechnique, Palaiseau 91120, France
| | - Martyn P. Nash
- Auckland Bioengineering Institute, University of Auckland, 70 Symonds Street, Auckland, New Zealand
- Department of Engineering Science, University of Auckland, 70 Symonds Street, Auckland, New Zealand
| | - Dominique Chapelle
- Inria and Paris-Saclay University, Bâtiment Alan Turing, 1 rue Honoré d'Estienne d'Orves, Campus de l'Ecole Polytechnique, Palaiseau 91120, France
| | - David A. Nordsletten
- Division of Imaging Sciences and Biomedical Engineering, King's College London, St Thomas’ Hospital, London SE1 7EH, UK
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81
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Lee J, Nordsletten D, Cookson A, Rivolo S, Smith N. In silico coronary wave intensity analysis: application of an integrated one-dimensional and poromechanical model of cardiac perfusion. Biomech Model Mechanobiol 2016; 15:1535-1555. [PMID: 27008197 PMCID: PMC5106513 DOI: 10.1007/s10237-016-0782-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 03/08/2016] [Indexed: 01/09/2023]
Abstract
Coronary wave intensity analysis (cWIA) is a diagnostic technique based on invasive measurement of coronary pressure and velocity waveforms. The theory of WIA allows the forward- and backward-propagating coronary waves to be separated and attributed to their origin and timing, thus serving as a sensitive and specific cardiac functional indicator. In recent years, an increasing number of clinical studies have begun to establish associations between changes in specific waves and various diseases of myocardium and perfusion. These studies are, however, currently confined to a trial-and-error approach and are subject to technological limitations which may confound accurate interpretations. In this work, we have developed a biophysically based cardiac perfusion model which incorporates full ventricular–aortic–coronary coupling. This was achieved by integrating our previous work on one-dimensional modelling of vascular flow and poroelastic perfusion within an active myocardial mechanics framework. Extensive parameterisation was performed, yielding a close agreement with physiological levels of global coronary and myocardial function as well as experimentally observed cumulative wave intensity magnitudes. Results indicate a strong dependence of the backward suction wave on QRS duration and vascular resistance, the forward pushing wave on the rate of myocyte tension development, and the late forward pushing wave on the aortic valve dynamics. These findings are not only consistent with experimental observations, but offer a greater specificity to the wave-originating mechanisms, thus demonstrating the value of the integrated model as a tool for clinical investigation.
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Affiliation(s)
- Jack Lee
- Department of Biomedical Engineering, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, London, UK.
| | - David Nordsletten
- Department of Biomedical Engineering, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, London, UK
| | - Andrew Cookson
- Department of Biomedical Engineering, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, London, UK
| | - Simone Rivolo
- Department of Biomedical Engineering, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, London, UK
| | - Nicolas Smith
- Department of Biomedical Engineering, King's College London, 3rd Floor, Lambeth Wing, St Thomas' Hospital, London, UK
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82
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Abstract
A review is presented of the physical principles governing the distribution of blood flow and blood pressure in the vascular system. The main factors involved are the pulsatile driving pressure generated by the heart, the flow characteristics of blood, and the geometric structure and mechanical properties of the vessels. The relationship between driving pressure and flow in a given vessel can be understood by considering the viscous and inertial forces acting on the blood. Depending on the vessel diameter and other physical parameters, a wide variety of flow phenomena can occur. In large arteries, the propagation of the pressure pulse depends on the elastic properties of the artery walls. In the microcirculation, the fact that blood is a suspension of cells strongly influences its flow properties and leads to a nonuniform distribution of hematocrit among microvessels. The forces acting on vessel walls include shear stress resulting from blood flow and circumferential stress resulting from blood pressure. Biological responses to these forces are important in the control of blood flow and the structural remodeling of vessels, and also play a role in major disease processes including hypertension and atherosclerosis. Consideration of hemodynamics is essential for a comprehensive understanding of the functioning of the circulatory system.
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Affiliation(s)
- Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, Arizona
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83
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Mu ZH, Jiang Z, Lin XJ, Wang LP, Xi Y, Zhang ZJ, Wang YT, Yang GY. Vessel Dilation Attenuates Endothelial Dysfunction Following Middle Cerebral Artery Occlusion in Hyperglycemic Rats. CNS Neurosci Ther 2016; 22:316-24. [PMID: 26842484 DOI: 10.1111/cns.12500] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/26/2015] [Accepted: 11/27/2015] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVES Dynamically observe cerebral vascular changes in hyperglycemic rats in vivo and explore the effect of diabetes on endothelial function after ischemic stroke. BACKGROUND Diabetes affects both large and small vessels in the brain, but the dynamic process and mechanism are unclear. METHODS We investigated the structural and functional changes of brain vasculature in living hyperglycemic rats and their impact on stroke outcomes via a novel technique: synchrotron radiation angiography. We also examined the effect of prolonged fasudil treatment on arterial reactivity and hemorrhagic transformation. Adult Sprague Dawley rats were treated by streptozotocin to induce type 1 diabetes. These hyperglycemic rats received fasudil pretreatment and then underwent transient middle cerebral artery occlusion. RESULTS We found that diabetes caused arteries narrowing in the circus Willis as early as 2 weeks after streptozotocin injection (P < 0.05). These vessels were further constricted after middle cerebral artery occlusion. L-NAME could induce regional constrictions and impaired relaxation in hyperglycemic animals. Furthermore, hemorrhagic transformation was also increased in the hyperglycemic rats compared to the control (P < 0.05). In fasudil-treated rats, the internal carotid artery narrowing was ameliorated and L-NAME-induced regional constriction was abolished. Importantly, stroke prognosis was improved in fasudil-treated rats compared to the control (P < 0.05). CONCLUSIONS Our dynamic angiographic data demonstrated that diabetes could impair the cerebral arterial reactivity. Prolonged fasudil treatment could attenuate arterial dysfunction and improve the prognosis of ischemic stroke by affecting both the large and small vasculature.
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Affiliation(s)
- Zhi-Hao Mu
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zhen Jiang
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xiao-Jie Lin
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Li-Ping Wang
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yan Xi
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.,Center for Biotechnology and Interdisciplinary Studies, Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Zhi-Jun Zhang
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Yong-Ting Wang
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Guo-Yuan Yang
- Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
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84
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Ladwiniec A, Cunnington MS, Rossington J, Mather AN, Alahmar A, Oliver RM, Nijjer SS, Davies JE, Thackray S, Alamgir F, Hoye A. Collateral donor artery physiology and the influence of a chronic total occlusion on fractional flow reserve. Circ Cardiovasc Interv 2016; 8:CIRCINTERVENTIONS.114.002219. [PMID: 25805570 DOI: 10.1161/circinterventions.114.002219] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND The presence of a concomitant chronic total coronary occlusion (CTO) and a large collateral contribution might alter the fractional flow reserve (FFR) of an interrogated vessel, rendering the FFR unreliable at predicting ischemia should the CTO vessel be revascularized and potentially affecting the decision on optimal revascularization strategy. We tested the hypothesis that donor vessel FFR would significantly change after percutaneous coronary intervention of a concomitant CTO. METHODS AND RESULTS In consecutive patients undergoing percutaneous coronary intervention of a CTO, coronary pressure and flow velocity were measured at baseline and hyperemia in proximal and distal segments of both nontarget vessels, before and after percutaneous coronary intervention. Hemodynamics including FFR, absolute coronary flow, and the coronary flow velocity-pressure gradient relation were calculated. After successful percutaneous coronary intervention in 34 of 46 patients, FFR in the predominant donor vessel increased from 0.782 to 0.810 (difference, 0.028 [0.012 to 0.044]; P=0.001). Mean decrease in baseline donor vessel absolute flow adjusted for rate pressure product: 177.5 to 139.9 mL/min (difference -37.6 [-62.6 to -12.6]; P=0.005), mean decrease in hyperemic flow: 306.5 to 272.9 mL/min (difference, -33.5 [-58.7 to -8.3]; P=0.011). Change in predominant donor vessel FFR correlated with angiographic (%) diameter stenosis severity (r=0.44; P=0.009) and was strongly related to stenosis severity measured by the coronary flow velocity-pressure gradient relation (r=0.69; P<0.001). CONCLUSIONS Recanalization of a CTO results in a modest increase in the FFR of the predominant collateral donor vessel associated with a reduction in coronary flow. A larger increase in FFR is associated with greater coronary stenosis severity.
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Affiliation(s)
- Andrew Ladwiniec
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.).
| | - Michael S Cunnington
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.)
| | - Jennifer Rossington
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.)
| | - Adam N Mather
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.)
| | - Albert Alahmar
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.)
| | - Richard M Oliver
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.)
| | - Sukhjinder S Nijjer
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.)
| | - Justin E Davies
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.)
| | - Simon Thackray
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.)
| | - Farquad Alamgir
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.)
| | - Angela Hoye
- From the Department of Cardiology, Castle Hill Hospital, Kingston-upon-Hull, United Kingdom (A.L., M.S.C., J.R., A.N.M., A.A., R.M.O., S.T., F.A., A.H.); Department of Academic Cardiology, Hull York Medical School, Kingston-upon-Hull, United Kingdom (A.L., A.H.); and Imperial College London, London, United Kingdom (S.S.N., J.E.D.)
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85
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Heyde B, Alessandrini M, Hermans J, Barbosa D, Claus P, D'hooge J. Anatomical Image Registration Using Volume Conservation to Assess Cardiac Deformation From 3D Ultrasound Recordings. IEEE TRANSACTIONS ON MEDICAL IMAGING 2016; 35:501-511. [PMID: 26394416 DOI: 10.1109/tmi.2015.2479556] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Myocardial deformation imaging can provide valuable insights in myocardial mechanics and help in the diagnosis, prognosis and follow-up of cardiac diseases. However, extracting these indices in 3D is challenging due to the limitations in spatial and temporal resolution of the current volumetric ultrasound systems. For this purpose, we developed an anatomical free-form deformation image registration framework which is locally adapted to the anatomy of the heart. In this work we explored whether incorporating a myocardial volume conservation regularizer would improve strain estimates. We evaluated our technique on in silico echo sequences featuring realistic speckle textures and showed the volume conservation regularizer to be beneficial in reducing strain errors further when used in combination with a smoothness penalty. This combination led to more physiological boundary conditions. It also made distinguishing ischemic from normal segments easier in clinical images.
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86
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Axell RG, Hoole SP, Hampton-Till J, White PA. RV diastolic dysfunction: time to re-evaluate its importance in heart failure. Heart Fail Rev 2015; 20:363-73. [PMID: 25633340 DOI: 10.1007/s10741-015-9472-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Right ventricular (RV) diastolic dysfunction was first reported as an indicator for the assessment of ventricular dysfunction in heart failure a little over two decades ago. However, the underlying mechanisms and precise role of RV diastolic dysfunction in heart failure remain poorly described. Complexities in the structure and function of the RV make the detailed assessment of the contractile performance challenging when compared to its left ventricular (LV) counterpart. LV dysfunction is known to directly affect patient outcome in heart failure. As such, the focus has therefore been on LV function. Nevertheless, a strategy for the diagnosis and assessment of RV diastolic dysfunction has not been established. Here, we review the different causal mechanisms underlying RV diastolic dysfunction, summarising the current assessment techniques used in a clinical environment. Finally, we explore the role of load-independent indices of RV contractility, derived from the conductance technique, to fully interrogate the RV and expand our knowledge and understanding of RV diastolic dysfunction. Accurate assessment of RV contractility may yield further important prognostic information that will benefit patients with diastolic heart failure.
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Affiliation(s)
- Richard G Axell
- Medical Physics and Clinical Engineering, Addenbrookes Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0QQ, UK,
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87
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The balance between the pro-inflammatory effect of plasma noradrenaline and the anti-inflammatory effect of neuronal noradrenaline determines the peripheral effects of noradrenaline. Med Hypotheses 2015; 85:517-29. [DOI: 10.1016/j.mehy.2014.08.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 08/18/2014] [Accepted: 08/24/2014] [Indexed: 12/22/2022]
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88
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Calderan J, Mao W, Sirois E, Sun W. Development of an In Vitro Model to Characterize the Effects of Transcatheter Aortic Valve on Coronary Artery Flow. Artif Organs 2015; 40:612-9. [PMID: 26510926 DOI: 10.1111/aor.12589] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Impairment of coronary artery flow, in either acute or chronic conditions, is a severe complication of transcatheter aortic valve (TAV) implantation, which can arise due to improper TAV positioning. However, little work has been done to quantify the effects of the TAV positioning on the coronary flow. In this study, a realistic in vitro model of coronary artery flow was developed and used to investigate the impact of TAV deployed orientations on coronary flow. The coronary hemodynamics was first replicated mathematically using a lumped parameter model with time-varying myocardial resistance. Based on the analytical model, two stepper motor controlled stopcock valves were integrated in a left heart simulator to represent the variable myocardial resistance in the experimental setup. The coronary flow and pressure waveforms obtained from the in vitro system were consistent with published data. With a TAV deployed in different orientations, the measured results demonstrated that TAV orientation does not have a significant impact on the coronary flow. The developed in vitro model can be further utilized to simulate coronary flow under various pathological conditions.
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Affiliation(s)
- Joseph Calderan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Wenbin Mao
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Eric Sirois
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Wei Sun
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
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Kühl JT, George RT, Mehra VC, Linde JJ, Chen M, Arai AE, Di Carli M, Kitagawa K, Dewey M, Lima JAC, Kofoed KF. Endocardial-epicardial distribution of myocardial perfusion reserve assessed by multidetector computed tomography in symptomatic patients without significant coronary artery disease: insights from the CORE320 multicentre study. Eur Heart J Cardiovasc Imaging 2015; 17:779-87. [PMID: 26341292 DOI: 10.1093/ehjci/jev206] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 08/02/2015] [Indexed: 12/15/2022] Open
Abstract
AIM Previous animal studies have demonstrated differences in perfusion and perfusion reserve between the subendocardium and subepicardium. 320-row computed tomography (CT) with sub-millimetre spatial resolution allows for the assessment of transmural differences in myocardial perfusion reserve (MPR) in humans. We aimed to test the hypothesis that MPR in all myocardial layers is determined by age, gender, and cardiovascular risk profile in patients with ischaemic symptoms or equivalent but without obstructive coronary artery disease (CAD). METHODS AND RESULTS A total of 149 patients enrolled in the CORE320 study with symptoms or signs of myocardial ischaemia and absence of significant CAD by invasive coronary angiography were scanned with static rest and stress CT perfusion. Myocardial attenuation densities were assessed at rest and during adenosine stress, segmented into 3 myocardial layers and 13 segments. MPR was higher in the subepicardium compared with the subendocardium (124% interquartile range [45, 235] vs. 68% [22,102], P < 0.001). Moreover, MPR in the septum was lower than in the inferolateral and anterolateral segments of the myocardium (55% [19, 104] vs. 89% [37, 168] and 124% [54, 270], P < 0.001). By multivariate analysis, high body mass index was significantly associated with reduced MPR in all myocardial layers when adjusted for cardiovascular risk factors (P = 0.02). CONCLUSION In symptomatic patients without significant coronary artery stenosis, distinct differences in endocardial-epicardial distribution of perfusion reserve may be demonstrated with static CT perfusion. Low MPR in all myocardial layers was observed specifically in obese patients.
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Affiliation(s)
- Jørgen Tobias Kühl
- Department of Cardiology, Rigshospitalet, University of Copenhagen, 2012, The Heart Centre, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Richard T George
- Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Vishal C Mehra
- Department of Medicine, Johns Hopkins University, Baltimore, MD, USA National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jesper J Linde
- Department of Cardiology, Rigshospitalet, University of Copenhagen, 2012, The Heart Centre, Blegdamsvej 9, 2100 Copenhagen, Denmark
| | - Marcus Chen
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Andrew E Arai
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | | | | | - Marc Dewey
- Charitè Medical School, Humboldt, Berlin, Germany
| | - Joao A C Lima
- Department of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Klaus Fuglsang Kofoed
- Department of Cardiology, Rigshospitalet, University of Copenhagen, 2012, The Heart Centre, Blegdamsvej 9, 2100 Copenhagen, Denmark Department of Radiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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90
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Wijntjens GWM, van Lavieren MA, van de Hoef TP, Piek JJ. Physiological assessment of coronary stenosis: a view from the coronary microcirculation. Interv Cardiol 2015. [DOI: 10.2217/ica.15.24] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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91
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Xie X, Wang Y. Theoretical Model of Coronary Blood Flow Regulation: Role of Myocardium Compressive Forces. Microcirculation 2015; 22:677-86. [PMID: 26193350 DOI: 10.1111/micc.12221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 07/14/2015] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Auto-regulatory reserve of coronary blood flow is nonuniformly distributed across the ventricular wall. MCF are thought to play an important role in determining the transmural distribution of myocardium blood flow. Here, impacts of MCF on coronary flow regulation are analyzed using a theoretical model. METHODS Coronary microvessels at various depths in the ventricular wall are represented by parallel segments. Nine vessel regions are connected in series to represent one parallel segment, which includes four vasoactive regions regulated by the wall tension, the shear stress and the metabolic demand. The nonuniform distribution of MCF is modeled and its effects on coronary flow regulation are taken into consideration by using a modified tension model and a vessel collapse model. Flow regulation behaviors in both normal and obstructed coronary circulation are simulated. RESULTS Model-predicted auto-regulatory curve is shifted to the high pressure region by including the effect of MCF. Model-predicted flow distributions in obstructed coronary circulation show that severe stenosis in coronary artery would first impede myocardial blood flow in subendocardial layer. CONCLUSIONS The model results indicate that MCF plays an important role in coronary flow regulation and also in determining the transmural distribution of myocardium blood flow.
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Affiliation(s)
- Xinzhou Xie
- Department of Electronic Engineering, Fudan University, Shanghai, China
| | - Yuanyuan Wang
- Department of Electronic Engineering, Fudan University, Shanghai, China.,Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai, China
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92
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Sinclair MD, Lee J, Cookson AN, Rivolo S, Hyde ER, Smith NP. Measurement and modeling of coronary blood flow. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2015; 7:335-56. [PMID: 26123867 DOI: 10.1002/wsbm.1309] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 05/19/2015] [Accepted: 05/21/2015] [Indexed: 01/10/2023]
Abstract
Ischemic heart disease that comprises both coronary artery disease and microvascular disease is the single greatest cause of death globally. In this context, enhancing our understanding of the interaction of coronary structure and function is not only fundamental for advancing basic physiology but also crucial for identifying new targets for treating these diseases. A central challenge for understanding coronary blood flow is that coronary structure and function exhibit different behaviors across a range of spatial and temporal scales. While experimental studies have sought to understand this feature by isolating specific mechanisms, in tandem, computational modeling is increasingly also providing a unique framework to integrate mechanistic behaviors across different scales. In addition, clinical methods for assessing coronary disease severity are continuously being informed and updated by findings in basic physiology. Coupling these technologies, computational modeling of the coronary circulation is emerging as a bridge between the experimental and clinical domains, providing a framework to integrate imaging and measurements from multiple sources with mathematical descriptions of governing physical laws. State-of-the-art computational modeling is being used to combine mechanistic models with data to provide new insight into coronary physiology, optimization of medical technologies, and new applications to guide clinical practice.
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Affiliation(s)
- Matthew D Sinclair
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Jack Lee
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Andrew N Cookson
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Simone Rivolo
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Eoin R Hyde
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK
| | - Nicolas P Smith
- Division of Imaging Sciences and Biomedical Engineering, British Heart Foundation (BHF) Centre of Excellence, King's College London, London, UK.,Department of Engineering, University of Auckland, Auckland, New Zealand
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93
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Heinonen I, Sorop O, de Beer VJ, Duncker DJ, Merkus D. What can we learn about treating heart failure from the heart's response to acute exercise? Focus on the coronary microcirculation. J Appl Physiol (1985) 2015; 119:934-43. [PMID: 26048972 DOI: 10.1152/japplphysiol.00053.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Coronary microvascular function and cardiac function are closely related in that proper cardiac function requires adequate oxygen delivery through the coronary microvasculature. Because of the close proximity of cardiomyocytes and coronary microvascular endothelium, cardiomyocytes not only communicate their metabolic needs to the coronary microvasculature, but endothelium-derived factors also directly modulate cardiac function. This review summarizes evidence that the myocardial oxygen balance is disturbed in the failing heart because of increased extravascular compressive forces and coronary microvascular dysfunction. The perturbations in myocardial oxygen balance are exaggerated during exercise and are due to alterations in neurohumoral influences, endothelial function, and oxidative stress. Although there is some evidence from animal studies that the myocardial oxygen balance can partly be restored by exercise training, it is largely unknown to what extent the beneficial effects of exercise training include improvements in endothelial function and/or oxidative stress in the coronary microvasculature and how these improvements are impacted by risk factors such as diabetes, obesity, and hypercholesterolemia.
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Affiliation(s)
- Ilkka Heinonen
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland
| | - Oana Sorop
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and
| | - Vincent J de Beer
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and
| | - Dirk J Duncker
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and
| | - Daphne Merkus
- Division of Experimental Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands; and
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94
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Sinclair M, Lee J, Schuster A, Chiribiri A, van den Wijngaard J, van Horssen P, Siebes M, Spaan JAE, Nagel E, Smith NP. Microsphere skimming in the porcine coronary arteries: Implications for flow quantification. Microvasc Res 2015; 100:59-70. [PMID: 25963318 DOI: 10.1016/j.mvr.2015.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/28/2015] [Accepted: 04/17/2015] [Indexed: 11/25/2022]
Abstract
Particle skimming is a phenomenon where particles suspended in fluid flowing through vessels distribute disproportionately to bulk fluid volume at junctions. Microspheres are considered a gold standard of intra-organ perfusion measurements and are used widely in studies of flow distribution and quantification. It has previously been hypothesised that skimming at arterial junctions is responsible for a systematic over-estimation of myocardial perfusion from microspheres at the subendocardium. Our objective is to integrate coronary arterial structure and microsphere distribution, imaged at high resolution, to test the hypothesis of microsphere skimming in a porcine left coronary arterial (LCA) network. A detailed network was reconstructed from cryomicrotome imaging data and a Poiseuille flow model was used to simulate flow. A statistical approach using Clopper-Pearson confidence intervals was applied to determine the prevalence of skimming at bifurcations in the LCA. Results reveal that microsphere skimming is most prevalent at bifurcations in the larger coronary arteries, namely the epicardial and transmural arteries. Bifurcations at which skimming was identified have significantly more asymmetric branching parameters. This finding suggests that when using thin transmural segments to quantify flow from microspheres, a skimming-related deposition bias may result in underestimation of perfusion in the subepicardium, and overestimation in the subendocardium.
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Affiliation(s)
- Matthew Sinclair
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK
| | - Jack Lee
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK
| | - Andreas Schuster
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK; Department of Cardiology and Pneumology, Georg-August-University, Göttingen, Germany; German Centre for Cardiovascular Research (DZHK, Partner Site Göttingen), Göttingen, Germany
| | - Amedeo Chiribiri
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK
| | - Jeroen van den Wijngaard
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Pepijn van Horssen
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Maria Siebes
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Jos A E Spaan
- Department of Biomedical Engineering & Physics, Academic Medical Centre, Amsterdam, The Netherlands
| | - Eike Nagel
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK
| | - Nicolas P Smith
- Division of Imaging Sciences and Biomedical Engineering, King's College London, British Heart Foundation (BHF) Centre of Excellence, UK; National Institute of Heath Research (NIHR) Biomedical Research Centre at Guy's and St. Thomas' NHS Foundation Trust, Lambeth Wing, St. Thomas' Hospital, UK; Wellcome Trust and Engineering and Physical Sciences Research Council (EPSRC) Medical Engineering Centre, Lambeth Wing, St. Thomas' Hospital, London, UK; Department of Engineering, University of Auckland, Auckland, New Zealand.
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95
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Xie X, Wang Y. Flow regulation in coronary vascular tree: a model study. PLoS One 2015; 10:e0125778. [PMID: 25928718 PMCID: PMC4416049 DOI: 10.1371/journal.pone.0125778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/25/2015] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Coronary blood flow can always be matched to the metabolic demand of the myocardium due to the regulation of vasoactive segments. Myocardial compressive forces play an important role in determining coronary blood flow but its impact on flow regulation is still unknown. The purpose of this study was to develop a coronary specified flow regulation model, which can integrate myocardial compressive forces and other identified regulation factors, to further investigate the coronary blood flow regulation behavior. METHOD A theoretical coronary flow regulation model including the myogenic, shear-dependent and metabolic responses was developed. Myocardial compressive forces were included in the modified wall tension model. Shear-dependent response was estimated by using the experimental data from coronary circulation. Capillary density and basal oxygen consumption were specified to corresponding to those in coronary circulation. Zero flow pressure was also modeled by using a simplified capillary model. RESULT Pressure-flow relations predicted by the proposed model are consistent with previous experimental data. The predicted diameter changes in small arteries are in good agreement with experiment observations in adenosine infusion and inhibition of NO synthesis conditions. Results demonstrate that the myocardial compressive forces acting on the vessel wall would extend the auto-regulatory range by decreasing the myogenic tone at the given perfusion pressure. CONCLUSIONS Myocardial compressive forces had great impact on coronary auto-regulation effect. The proposed model was proved to be consistent with experiment observations and can be employed to investigate the coronary blood flow regulation effect in physiological and pathophysiological conditions.
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Affiliation(s)
- Xinzhou Xie
- Department of Electronic Engineering, Fudan University, Shanghai, China
| | - Yuanyuan Wang
- Department of Electronic Engineering, Fudan University, Shanghai, China
- Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai, China
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96
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Stoller M, Seiler C. Pathophysiology of coronary collaterals. Curr Cardiol Rev 2015; 10:38-56. [PMID: 23701025 PMCID: PMC3968593 DOI: 10.2174/1573403x113099990005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 02/28/2013] [Accepted: 04/19/2013] [Indexed: 11/22/2022] Open
Abstract
While the existence of structural adaptation of coronary anastomoses is undisputed, the potential of coronary
collaterals to be capable of functional adaptation has been questioned. For many years, collateral vessels were thought to
be rigid tubes allowing only limited blood flow governed by the pressure gradient across them. This concept was consistent
with the notion that although collaterals could provide adequate blood flow to maintain resting levels, they would be
unable to increase blood flow sufficiently in situations of increased myocardial oxygen demand. However, more recent studies have demonstrated the capability of the collateral circulation to deliver sufficient blood
flow even during exertion or pharmacologic stress. Moreover, it has been shown that increases in collateral flow could be
attributed directly to collateral vasomotion. This review summarizes the pathophysiology of the coronary collateral circulation, ie the functional adapation of coronary
collaterals to acute alterations in the coronary circulation.
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Affiliation(s)
| | - Christian Seiler
- Department of Cardiology, University Hospital, CH-3010 Bern, Switzerland.
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97
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One-Dimensional Modelling of the Coronary Circulation. Application to Noninvasive Quantification of Fractional Flow Reserve (FFR). ACTA ACUST UNITED AC 2015. [DOI: 10.1007/978-3-319-15799-3_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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98
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Vejdani-Jahromi M, Nagle M, Trahey GE, Wolf PD. Ultrasound shear wave elasticity imaging quantifies coronary perfusion pressure effect on cardiac compliance. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:465-73. [PMID: 25291788 PMCID: PMC4765376 DOI: 10.1109/tmi.2014.2360835] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Diastolic heart failure (DHF) is a major source of cardiac related morbidity and mortality in the world today. A major contributor to, or indicator of DHF is a change in cardiac compliance. Currently, there is no accepted clinical method to evaluate the compliance of cardiac tissue in diastolic dysfunction. Shear wave elasticity imaging (SWEI) is a novel ultrasound-based elastography technique that provides a measure of tissue stiffness. Coronary perfusion pressure affects cardiac stiffness during diastole; we sought to characterize the relationship between these two parameters using the SWEI technique. In this work, we demonstrate how changes in coronary perfusion pressure are reflected in a local SWEI measurement of stiffness during diastole. Eight Langendorff perfused isolated rabbit hearts were used in this study. Coronary perfusion pressure was changed in a randomized order (0-90 mmHg range) and SWEI measurements were recorded during diastole with each change. Coronary perfusion pressure and the SWEI measurement of stiffness had a positive linear correlation with the 95% confidence interval (CI) for the slope of 0.009-0.011 m/s/mmHg ( R(2) = 0.88 ). Furthermore, shear modulus was linearly correlated to the coronary perfusion pressure with the 95% CI of this slope of 0.035-0.042 kPa/mmHg ( R(2) = 0.83). In conclusion, diastolic SWEI measurements of stiffness can be used to characterize factors affecting cardiac compliance specifically the mechanical interaction (cross-talk) between perfusion pressure in the coronary vasculature and cardiac muscle. This relationship was found to be linear over the range of pressures tested.
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Affiliation(s)
| | - Matt Nagle
- Biomedical Engineering Department, Duke University, Durham, NC 27708 USA
| | - Gregg E. Trahey
- Biomedical Engineering Department, Duke University, Durham, NC 27708 USA
| | - Patrick D. Wolf
- Biomedical Engineering Department, Duke University, Durham, NC 27708 USA
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99
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van Bragt KA, Nasrallah HM, Kuiper M, van Hunnik A, Kuijpers NHL, Schotten U, Verheule S. Dynamic regulation of atrial coronary blood flow in healthy adult pigs. Heart Rhythm 2015; 12:991-1000. [PMID: 25595927 DOI: 10.1016/j.hrthm.2015.01.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND There are several indications for a mismatch between atrial oxygen supply and demand during atrial fibrillation (AF), but atrial coronary flow regulation has not been investigated extensively. OBJECTIVE The purpose of this study was to characterize the dynamic regulation of atrial coronary flow in pigs. METHODS In anesthetized open-chest pigs, Doppler flow probes were placed around left atrial (LA) and left ventricular (LV) branches of the circumflex artery. Pressures and work indices were measured simultaneously. Systolic and diastolic flow contribution, flow response kinetics, and relationship between pressures, work, and flow were investigated during sinus rhythm, atrial pacing, and acute AF. RESULTS During atrial systole, LA flow decreased. Only 2% of total LA flow occurred during atrial systole. Pacing with 2:1 AV block and infusion of acetylcholine revealed that atrial contraction itself impeded atrial coronary flow. The response to sudden changes in heart rate was slower in LA compared to LV. Both LA and LV vascular conductance were positively correlated with work. After the cessation of acute AF, the LA showed a more pronounced phase of supranormal vascular conductance than the LV, indicating a period of atrial reactive hyperemia. CONCLUSION In healthy adult pigs, atrial coronary flow is impeded by atrial contraction. Although atrial coronary blood flow is positively correlated with atrial external work, it reacts more slowly to changes in rate than ventricular flow. The occurrence of a pronounced hyperemic phase after acute AF supports the notion of a significant supply-demand mismatch during AF.
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Affiliation(s)
- Kelly A van Bragt
- Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands
| | - Hussein M Nasrallah
- Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands
| | - Marion Kuiper
- Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands
| | - Arne van Hunnik
- Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands
| | - Nico H L Kuijpers
- Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands
| | - Ulrich Schotten
- Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands
| | - Sander Verheule
- Department of Physiology, Faculty of Medicine, Maastricht University, The Netherlands.
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100
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Zhu G, Groneberg D, Sikka G, Hori D, Ranek MJ, Nakamura T, Takimoto E, Paolocci N, Berkowitz DE, Friebe A, Kass DA. Soluble guanylate cyclase is required for systemic vasodilation but not positive inotropy induced by nitroxyl in the mouse. Hypertension 2014; 65:385-92. [PMID: 25452469 DOI: 10.1161/hypertensionaha.114.04285] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nitroxyl (HNO), the reduced and protonated form of nitric oxide (NO·), confers unique physiological effects including vasorelaxation and enhanced cardiac contractility. These features have spawned current pharmaceutical development of HNO donors as heart failure therapeutics. HNO interacts with selective redox sensitive cysteines to effect signaling but is also proposed to activate soluble guanylate cyclase (sGC) in vitro to induce vasodilation and potentially enhance contractility. Here, we tested whether sGC stimulation is required for these HNO effects in vivo and if HNO also modifies a redox-sensitive cysteine (C42) in protein kinase G-1α to control vasorelaxation. Intact mice and isolated arteries lacking the sGC-β subunit (sGCKO, results in full sGC deficiency) or expressing solely a redox-dead C42S mutant protein kinase G-1α were exposed to the pure HNO donor, CXL-1020. CXL-1020 induced dose-dependent systemic vasodilation while increasing contractility in controls; however, vasodilator effects were absent in sGCKO mice whereas contractility response remained. The CXL-1020 dose reversing 50% of preconstricted force in aortic rings was ≈400-fold greater in sGCKO than controls. Cyclic-GMP and cAMP levels were unaltered in myocardium exposed to CXL-1020, despite its inotropic-vasodilator activity. In protein kinase G-1α(C42S) mice, CXL-1020 induced identical vasorelaxation in vivo and in isolated aortic and mesenteric vessels as in littermate controls. In both groups, dilation was near fully blocked by pharmacologically inhibiting sGC. Thus, sGC and cGMP-dependent signaling are necessary and sufficient for HNO-induced vasodilation in vivo but are not required for positive inotropic action. Redox modulation of protein kinase G-1α is not a mechanism for HNO-mediated vasodilation.
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Affiliation(s)
- Guangshuo Zhu
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD
| | - Dieter Groneberg
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD
| | - Gautam Sikka
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD
| | - Daijiro Hori
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD
| | - Mark J Ranek
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD
| | - Taishi Nakamura
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD
| | - Eiki Takimoto
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD
| | - Nazareno Paolocci
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD
| | - Dan E Berkowitz
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD
| | - Andreas Friebe
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD
| | - David A Kass
- From the Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore MD (G.Z., M.J.R., T.N., E.T., N.P., D.A.K.); Institut of Vegetative Physiology, Julius Maximilians-Universität Würzburg, Würzburg, Germany (D.G., A.F.); and Departments of Anesthesia (G.S., D.E.B.) and Surgery (D.H.), Johns Hopkins Medical Institutions, Baltimore MD.
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