scholarly journals Pulmonary vascular resistance and compliance relationship in pulmonary hypertension

2015 ◽  
Vol 46 (4) ◽  
pp. 1178-1189 ◽  
Author(s):  
Denis Chemla ◽  
Edmund M.T. Lau ◽  
Yves Papelier ◽  
Pierre Attal ◽  
Philippe Hervé
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Pulmonary Circulation ◽  
Arterial Compliance ◽  
Pulmonary Arteries ◽  
Transpulmonary Pressure ◽  
Total Arterial Compliance ◽  
Arterial Load ◽  
Pulmonary Arterial

Right ventricular adaptation to the increased pulmonary arterial load is a key determinant of outcomes in pulmonary hypertension (PH). Pulmonary vascular resistance (PVR) and total arterial compliance (C) quantify resistive and elastic properties of pulmonary arteries that modulate the steady and pulsatile components of pulmonary arterial load, respectively. PVR is commonly calculated as transpulmonary pressure gradient over pulmonary flow and total arterial compliance as stroke volume over pulmonary arterial pulse pressure (SV/PApp). Assuming that there is an inverse, hyperbolic relationship between PVR and C, recent studies have popularised the concept that their product (RC-time of the pulmonary circulation, in seconds) is “constant” in health and diseases. However, emerging evidence suggests that this concept should be challenged, with shortened RC-times documented in post-capillary PH and normotensive subjects. Furthermore, reported RC-times in the literature have consistently demonstrated significant scatter around the mean. In precapillary PH, the true PVR can be overestimated if one uses the standard PVR equation because the zero-flow pressure may be significantly higher than pulmonary arterial wedge pressure. Furthermore, SV/PApp may also overestimate true C. Further studies are needed to clarify some of the inconsistencies of pulmonary RC-time, as this has major implications for our understanding of the arterial load in diseases of the pulmonary circulation.

scholarly journals The isobaric pulmonary arterial compliance in pulmonary hypertension

2021 ◽  
pp. 00941-2020
Author(s):  
Denis Chemla ◽  
Emmanuelle Berthelot ◽  
Jason Weatherald ◽  
Edmund M. T. Lau ◽  
Laurent Savale ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Arterial Compliance ◽  
Pulmonary Arteries ◽  
Right Heart ◽  
Right Heart Catheterisation ◽  
Strain Behaviour ◽  
Arterial Load ◽  
Pulmonary Arterial ◽  
Vascular Beds ◽  
The Right

Pulmonary hypertension (PH) is associated with stiffening of pulmonary arteries which increases right ventricular pulsatile loading. High pulmonary artery wedge pressure (PAWP) in postcapillary PH (Pc-PH) further decreases PA compliance (PAC) at a given pulmonary vascular resistance (PVR) compared to precapillary PH, thus responsible for a higher total arterial load. In all other vascular beds, arterial compliance is considered as mainly determined by the distending pressure, due to non-linear stress-strain behaviour of arteries. We tested the applicability, advantages and drawbacks of two comparison methods of PAC depending on the level of mean PA pressure mPAP (isobaric PAC) or PVR.Right heart catheterisation data including PAC (stroke volume/pulse pressure) were obtained in 112Pc-PH (of whom 61 had combined postcapillary and precapillary PH) and 719 idiopathic pulmonary arterial hypertension (iPAH).PAC could be compared over the same mPAP range (25–66 mmHg) in 792/831 patients (95.3%) and over the same PVR range (3–10.7 WU) in only 520/831 patients (62.6%). The main assumption underlying comparisons at a given PVR was not verified as the PVR×PAC product (RC-time) was not constant but on the contrary more variable than mPAP. In the 788/831 (94.8%) patients studied over the same PAC range (0.62–6.5 mL·mmHg−1), PVR and thus total arterial load tended to be higher in iPAH.Our study favours comparing PAC at fixed mPAP level (isobaric PAC) rather than at fixed PVR. A reappraisal of the effects of PAWP on the pulsatile and total arterial load put on the right heart is needed, and this point deserves further studies.

scholarly journals Sex Dimorphism in Pulmonary Hypertension: The Role of the Sex Chromosomes

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 779
Author(s):  
Daria S. Kostyunina ◽  
Paul McLoughlin
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Sex Chromosomes ◽  
Bone Morphogenetic Protein 2 ◽  
Sex Dimorphism ◽  
Pulmonary Arterial ◽  
The Impact

Pulmonary hypertension (PH) is a condition characterised by an abnormal elevation of pulmonary artery pressure caused by an increased pulmonary vascular resistance, frequently leading to right ventricular failure and reduced survival. Marked sexual dimorphism is observed in patients with pulmonary arterial hypertension, a form of pulmonary hypertension with a particularly severe clinical course. The incidence in females is 2–4 times greater than in males, although the disease is less severe in females. We review the contribution of the sex chromosomes to this sex dimorphism highlighting the impact of proteins, microRNAs and long non-coding RNAs encoded on the X and Y chromosomes. These genes are centrally involved in the cellular pathways that cause increased pulmonary vascular resistance including the production of reactive oxygen species, altered metabolism, apoptosis, inflammation, vasoconstriction and vascular remodelling. The interaction with genetic mutations on autosomal genes that cause heritable pulmonary arterial hypertension such as bone morphogenetic protein 2 (BMPR2) are examined. The mechanisms that can lead to differences in the expression of genes located on the X chromosomes between females and males are also reviewed. A better understanding of the mechanisms of sex dimorphism in this disease will contribute to the development of more effective therapies for both women and men.

scholarly journals Decreased time constant of the pulmonary circulation in chronic thromboembolic pulmonary hypertension

2013 ◽  
Vol 305 (2) ◽  
pp. H259-H264 ◽  
Author(s):  
Robert V. MacKenzie Ross ◽  
Mark R. Toshner ◽  
Elaine Soon ◽  
Robert Naeije ◽  
Joanna Pepke-Zaba
Keyword(s):  
Pulmonary Hypertension ◽  
Time Constant ◽  
Pulmonary Circulation ◽  
Wave Reflection ◽  
Arterial Compliance ◽  
Chronic Thromboembolic Pulmonary Hypertension ◽  
Left Heart Failure ◽  
Thromboembolic Pulmonary Hypertension ◽  
Pulmonary Arterial ◽  
Rc Time Constant

This study analyzed the relationship between pulmonary vascular resistance (PVR) and pulmonary arterial compliance ( Ca) in patients with idiopathic pulmonary arterial hypertension (IPAH) and proximal chronic thromboembolic pulmonary hypertension (CTEPH). It has recently been shown that the time constant of the pulmonary circulation (RC time constant), or PVR × Ca, remains unaltered in various forms and severities of pulmonary hypertension, with the exception of left heart failure. We reasoned that increased wave reflection in proximal CTEPH would be another cause of the decreased RC time constant. We conducted a retrospective analysis of invasive pulmonary hemodynamic measurements in IPAH ( n = 78), proximal CTEPH ( n = 91) before (pre) and after (post) pulmonary endarterectomy (PEA), and distal CTEPH ( n = 53). Proximal CTEPH was defined by a postoperative mean pulmonary artery pressure (PAP) of ≤25 mmHg. Outcome measures were the RC time constant, PVR, Ca, and relationship between systolic and mean PAPs. The RC time constant for pre-PEA CTEPH was 0.49 ± 0.11 s compared with post-PEA-CTEPH (0.37 ± 0.11 s, P < 0.0001), IPAH (0.63 ± 0.14 s, P < 0.001), and distal CTEPH (0.55 ± 0.12 s, P < 0.05). A shorter RC time constant was associated with a disproportionate decrease in systolic PAP with respect to mean PAP. We concluded that the pulmonary RC time constant is decreased in proximal CTEPH compared with IPAH, pre- and post-PEA, which may be explained by increased wave reflection but also, importantly, by persistent structural changes after the removal of proximal obstructions. A reduced RC time constant in CTEPH is in accord with a wider pulse pressure and hence greater right ventricular work for a given mean PAP.

scholarly journals Pulmonary Hypertension Due to Left Heart Disease

Hypertension ◽  
2020 ◽  
Vol 75 (6) ◽  
pp. 1397-1408 ◽  
Author(s):  
Mohammed S. Al-Omary ◽  
Stuart Sugito ◽  
Andrew J. Boyle ◽  
Aaron L. Sverdlov ◽  
Nicholas J. Collins
Keyword(s):  
Pulmonary Hypertension ◽  
Heart Disease ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Left Atrial ◽  
Left Atrial Pressure ◽  
Left Heart ◽  
Pulmonary Arterial

Pulmonary hypertension (PH) due to left heart disease (LHD) is the most common type of PH and is defined as mean pulmonary artery systolic pressure of >20 mm Hg and pulmonary capillary wedge pressure >15 mm Hg during right heart catheterization. LHD may lead to elevated left atrial pressure alone, which in the absence of intrinsic pulmonary vascular disease will result in PH without changes in pulmonary vascular resistance. Persistent elevation in left atrial pressure may, however, also be associated with subsequent pulmonary vascular remodeling, vasoconstriction, and an increase in pulmonary vascular resistance. Hence, there are 2 subgroups of PH due to LHD, isolated postcapillary PH and combined post- and precapillary PH, with these groups have differing clinical implications. Differentiation of pulmonary arterial hypertension and PH due to LHD is critical to guide management planning; however, this may be challenging. Older patients, patients with metabolic syndrome, and patients with imaging and clinical features consistent with left ventricular dysfunction are suggestive of LHD etiology rather than pulmonary arterial hypertension. Hemodynamic measures such as diastolic pressure gradient, transpulmonary gradient, and pulmonary vascular resistance may assist to differentiate pre- from postcapillary PH and offer prognostic insights. However, these are influenced by fluid status and heart failure treatment. Pulmonary arterial hypertension therapies have been trialed in the treatment with concerning results reflecting disease heterogeneity, variation in inclusion criteria, and mixed end point criteria. The aim of this review is to provide an updated definition, discuss possible pathophysiology, clinical aspects, and the available treatment options for PH due to LHD.

Effect of high intra-alveolar O2 tensions on pulmonary circulation in perfused lungs of dogs

1965 ◽  
Vol 208 (1) ◽  
pp. 130-138 ◽  
Author(s):  
G. J. A. Cropp
Keyword(s):  
Blood Flow ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Pulmonary Circulation ◽  
Time Course ◽  
Systemic Circulation ◽  
The Body ◽  
Arterial Blood ◽  
Pulmonary Parenchyma ◽  
Pulmonary Arterial

The resistance to blood flow in the pulmonary circulation of dogs (PVR) increased when their lungs were ventilated with 95–100% oxygen and were perfused with blood that recirculated only through the pulmonary circulation; the systemic circulation was perfused independently. This increase in PVR occurred even when nerves were cut or blocked but was abolished by inhaled isopropylarterenol aerosol. Elevation of intra-alveolar Po2 without increase in pulmonary arterial blood Po2 was sufficient to increase pulmonary vascular resistance. The pulmonary venules or veins were thought to be the likely site of the constriction. These reactions were qualitatively similar to those produced by injection of serotonin or histamine into the pulmonary circulation. The time course of the response and failure to obtain it when the blood was perfused through the remainder of the body before it re-entered the pulmonary circulation are compatible with a theory that high intra-alveolar O2 tension activates a vasoconstrictor material in the pulmonary parenchyma.

Pregnancy blunts pulmonary vascular reactivity in dogs

1980 ◽  
Vol 239 (3) ◽  
pp. H297-H301 ◽  
Author(s):  
L. G. Moore ◽  
J. T. Reeves
Keyword(s):  
Arterial Pressure ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Pulmonary Circulation ◽  
Vascular Reactivity ◽  
Pulmonary Arterial Pressure ◽  
Acute Hypoxia ◽  
Limited Data ◽  
Mean Pulmonary Arterial Pressure ◽  
Pulmonary Arterial

Pregnancy decreases systemic vascular reactivity but comparatively little is known about the effects of pregnancy on the pulmonary circulation. Pulmonary vascular resistance (PVR) during acute hypoxia was lower (P < 0.01) in eight intact anesthetized pregnant dogs compared to the same animals postpartum. Mean pulmonary arterial pressure (Ppa) and PVR during infusion of prostaglandin (PG) F2 alpha were also reduced during pregnancy. Nonpregnant female dogs (n = 5) treated with estrogen (0.001 mg x kg-1 x da-1) for 2 wk had decreased Ppa (P < 0.01) during acute hypoxia compared to control measurements, but PVR was unchanged during hypoxia and PGF2 alpha infusion. Treatment with progesterone in four dogs had no effect on pulmonary vascular reactivity to hypoxia or PGF2 alpha. Inhibition of circulating PG with meclofenamate in four dogs during pregnancy did not appear to restore pulmonary vascular reactivity. Blunted pulmonary vascular reactivity is suggested by the limited data available for women, but is not seen in pregnant cows. We conclude that pregnancy decreases pulmonary as well as systemic vascular reactivity in the dog, but the mechanism is unclear.

scholarly journals Increased Red Blood Cell Stiffness Increases Pulmonary Vascular Resistance and Pulmonary Arterial Pressure

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
David A. Schreier ◽  
Omid Forouzan ◽  
Timothy A. Hacker ◽  
John Sheehan ◽  
Naomi Chesler
Keyword(s):  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Arterial Compliance ◽  
Cell Stiffness ◽  
The Third ◽  
Vascular Impedance ◽  
Increased Risk ◽  
Before And After ◽  
Pulmonary Arterial ◽  
The Impact

Patients with sickle cell anemia (SCD) and pulmonary hypertension (PH) have a significantly increased risk of sudden death compared to patients with SCD alone. Sickled red blood cells (RBCs) are stiffer, more dense, more frequently undergo hemolysis, and have a sixfold shorter lifespan compared to normal RBCs. Here, we sought to investigate the impact of increased RBC stiffness, independent of other SCD-related biological and mechanical RBC abnormalities, on the hemodynamic changes that ultimately cause PH and increase mortality in SCD. To do so, pulmonary vascular impedance (PVZ) measures were recorded in control C57BL6 mice before and after ∼50 μl of blood (Hct = 45%) was extracted and replaced with an equal volume of blood containing either untreated RBCs or RBCs chemically stiffened with glutaraldehyde (Hct = 45%). Chemically stiffened RBCs increased mean pulmonary artery pressure (mPAP) (13.5 ± 0.6 mmHg at baseline to 23.2 ± 0.7 mmHg after the third injection), pulmonary vascular resistance (PVR) (1.23 ± 0.11 mmHg*min/ml at baseline to 2.24 ± 0.14 mmHg*min/ml after the third injection), and wave reflections (0.31 ± 0.02 at baseline to 0.43 ± 0.03 after the third injection). Chemically stiffened RBCs also decreased cardiac output, but did not change hematocrit, blood viscosity, pulmonary arterial compliance, or heart rate. The main finding of this study is that increased RBC stiffness alone affects pulmonary pulsatile hemodynamics, which suggests that RBC stiffness plays an important role in the development of PH in patients with SCD.

scholarly journals Hydrogen Sulfide Metabolism and Pulmonary Hypertension

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1477
Author(s):  
Lukas Roubenne ◽  
Roger Marthan ◽  
Bruno Le Le Grand ◽  
Christelle Guibert
Keyword(s):  
Pulmonary Hypertension ◽  
Hydrogen Sulfide ◽  
Pulmonary Circulation ◽  
Pulmonary Arteries ◽  
K Channel ◽  
Protective Effects ◽  
Pulmonary Arterial ◽  
Regulatory Functions

Pulmonary hypertension (PH) is a severe and multifactorial disease characterized by a progressive elevation of pulmonary arterial resistance and pressure due to remodeling, inflammation, oxidative stress, and vasoreactive alterations of pulmonary arteries (PAs). Currently, the etiology of these pathological features is not clearly understood and, therefore, no curative treatment is available. Since the 1990s, hydrogen sulfide (H2S) has been described as the third gasotransmitter with plethoric regulatory functions in cardiovascular tissues, especially in pulmonary circulation. Alteration in H2S biogenesis has been associated with the hallmarks of PH. H2S is also involved in pulmonary vascular cell homeostasis via the regulation of hypoxia response and mitochondrial bioenergetics, which are critical phenomena affected during the development of PH. In addition, H2S modulates ATP-sensitive K+ channel (KATP) activity, and is associated with PA relaxation. In vitro or in vivo H2S supplementation exerts antioxidative and anti-inflammatory properties, and reduces PA remodeling. Altogether, current findings suggest that H2S promotes protective effects against PH, and could be a relevant target for a new therapeutic strategy, using attractive H2S-releasing molecules. Thus, the present review discusses the involvement and dysregulation of H2S metabolism in pulmonary circulation pathophysiology.

Differential Effects of Terlipressin on Pulmonary and Systemic Hemodynamics in Patients With Cirrhosis and Pulmonary Hypertension

Angiology ◽  
2011 ◽  
Vol 63 (3) ◽  
pp. 199-205 ◽  
Author(s):  
Georgios N. Kalambokis ◽  
Konstantinos Pappas ◽  
Epameinondas V. Tsianos
Keyword(s):  
Pulmonary Hypertension ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Systemic Hemodynamic ◽  
Hemodynamic Improvement ◽  
Pulmonary Arterial ◽  
Group 2 ◽  
Group 1

Terlipressin has been associated with pulmonary arterial vasodilation in patients with pulmonary hypertension (PH). We investigated the effects of terlipressin on pulmonary vascular resistance (PVR) in patients with cirrhosis without and with PH. Pulmonary vascular resistance and cardiac output (CO) by Doppler ultrasound, mean arterial pressure (MAP), and systemic vascular resistance (SVR) were evaluated in patients with cirrhosis with PVR –120 dyne s cm−5 (group 1, n = 20) and PVR >120 dyne s cm−5 (group 2, n = 10) before and 30 minutes after terlipressin infusion (2 mg). After terlipressin, PVR increased significantly in group 1 (96.1 ± 20.2 vs 85.1 ± 18 dyne s cm−5; P = .004) but decreased significantly in group 2 (170.4 ± 37.8 vs 157.8 ± 28.1 dyne s cm−5; P= .04). Pulmonary vascular resistance changes in group 2 correlated significantly with baseline PVR ( r = −0.632; P = .04). Terlipressin induced a significant increase in MAP and SVR and a significant decrease in CO in both groups. Terlipressin significantly reduces pulmonary pressures in patients with cirrhosis having PH together with systemic hemodynamic improvement.

Ontogeny of NO activity and response to inhaled NO in the developing ovine pulmonary circulation

1994 ◽  
Vol 267 (5) ◽  
pp. H1955-H1961 ◽  
Author(s):  
J. P. Kinsella ◽  
D. D. Ivy ◽  
S. H. Abman
Keyword(s):  
Nitric Oxide ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Pulmonary Circulation ◽  
Hemodynamic Effects ◽  
Fetal Sheep ◽  
Pulmonary Vasodilation ◽  
Ovine Fetus ◽  
Pulmonary Arterial ◽  
Inhaled No

To determine maturation-related changes in nitric oxide (NO) activity in the developing pulmonary circulation, we studied the hemodynamic effects of endogenous NO inhibition under basal conditions in the premature ovine fetus and the response to birth-related stimuli and exogenous NO in 30 fetal sheep at three different gestational ages. At 0.95 term, pulmonary vasodilation during inhaled NO (20 parts per million) was equivalent to the dilator response to 100% O2, but at 0.86 term vasodilation during inhaled NO was greater than the dilator response to 100% O2 (P < 0.05). At 0.78 term, left pulmonary arterial flow (QLPA) did not increase with exposure to either NO or 100% O2. Intrapulmonary infusion of nitro-L-arginine (L-NA) increased basal pulmonary vascular resistance 38% in the premature fetus at 0.78 term. L-NA treatment decreased the ventilation-induced rise in QLPA by 60% compared with controls (P < 0.05). Inhaled NO but not 100% O2 increased QLPA after L-NA treatment to levels achieved with ventilation alone in the controls. We conclude that in the premature pulmonary circulation (0.78 term) 1) basal pulmonary vascular resistance is modulated by endogenous NO, 2) pulmonary vasodilation at birth is partly mediated by endogenous NO activity, and 3) inhaled NO causes potent vasodilation.

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