Effects of sildenafil on hypoxic pulmonary vascular function in dogs

2006 ◽  
Vol 101 (4) ◽  
pp. 1085-1090 ◽  
Author(s):  
Pierre Fesler ◽  
Alberto Pagnamenta ◽  
Benoit Rondelet ◽  
François Kerbaul ◽  
Robert Naeije
Keyword(s):  
Arterial Pressure ◽  
Right Ventricular ◽  
Vascular Function ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Characteristic Impedance ◽  
Systemic Arterial Pressure ◽  
Pulmonary Vasodilators ◽  
Hydraulic Load ◽  
Pulmonary Arterial ◽  
Inhaled No

Sildenafil has been shown to be an effective treatment of pulmonary arterial hypertension and is believed to present with pulmonary selectivity. This study was designed to determine the site of action of sildenafil compared with inhaled nitric oxide (NO) and intravenous sodium nitroprusside (SNP), known as selective and nonselective pulmonary vasodilators, respectively. Inhaled NO (40 ppm), and maximum tolerated doses of intravenous SNP and sildenafil, (5 μg·kg−1·min−1 and 0.1 mg·kg−1·h−1), respectively, were administered to eight dogs ventilated in hypoxia. Pulmonary vascular resistance (PVR) was evaluated by pulmonary arterial pressure (Ppa) minus left atrial pressure (Pla) vs. flow curves, and partitioned into arterial and venous segments by the occlusion method. Right ventricular hydraulic load was defined by pulmonary arterial characteristic impedance (Zc) and elastance (Ea) calculations. Right ventricular arterial coupling was estimated by the ratio of end-systolic elastance (Ees) to Ea. Decreasing the inspired oxygen fraction from 0.4 to 0.1 increased Ppa − Pla at a standardized flow of 3 l·min−1·m−2 from 6 ± 1 to 18 ± 1 mmHg (mean ± SE). Ppa − Pla was decreased to 9 ± 1 by inhaled NO, 14 ± 1 by SNP, and 14 ± 1 mmHg by sildenafil. The partition of PVR, Zc, Ea, and Ees/Ea was not affected by the three interventions. Inhaled NO did not affect systemic arterial pressure, which was similarly decreased by sildenafil and SNP, from 115 ± 4 to 101 ± 4 and 98 ± 5 mmHg, respectively. We conclude that inhaled NO inhibits hypoxic pulmonary vasoconstriction more effectively than sildenafil or SNP, and sildenafil shows no more selectivity for the pulmonary circulation than SNP.

Inhaled nitric oxide partially reverses hypoxic pulmonary vasoconstriction in the dog

1994 ◽  
Vol 76 (3) ◽  
pp. 1350-1355 ◽  
Author(s):  
J. A. Romand ◽  
M. R. Pinsky ◽  
L. Firestone ◽  
H. A. Zar ◽  
J. R. Lancaster
Keyword(s):  
Nitric Oxide ◽  
Arterial Pressure ◽  
Pulmonary Vascular Resistance ◽  
Vascular Resistance ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Canine Model ◽  
Systemic Arterial Pressure ◽  
Vasomotor Tone ◽  
Pulmonary Vasoconstriction ◽  
Pulmonary Arterial

Nitric oxide (NO) inhaled during a hypoxia-induced increase in pulmonary vasomotor tone decreases pulmonary arterial pressure (Ppa). We conducted this study to better characterize the hemodynamic effects induced by NO inhalation during hypoxic pulmonary vasoconstriction in 11 anesthetized ventilated dogs. Arterial and venous systemic and pulmonary pressures and aortic flow probe-derived cardiac output were recorded, and nitrosylhemoglobin (NO-Hb) and methemoglobin (MetHb) were measured. The effects of 5 min of NO inhalation at 0, 17, 28, 47, and 0 ppm during hyperoxia (inspiratory fraction of O2 = 0.5) and hypoxia (inspiratory fraction of O2 = 0.16) were observed. NO inhalation has no measurable effects during hyperoxia. Hypoxia induced an increase in Ppa that reached plateau levels after 5 min. Exposure to 28 and 47 ppm NO induced an immediate (< 30 s) decrease in Ppa and calculated pulmonary vascular resistance (P < 0.05 each) but did not return either to baseline hyperoxic values. Increasing the concentration of NO to 74 and 145 ppm in two dogs during hypoxia did not induce any further decreases in Ppa. Reversing hypoxia while NO remained at 47 ppm further decreased Ppa and pulmonary vascular resistance to baseline values. NO inhalation did not induce decreases in systemic arterial pressure. MetHb remained low, and NO-Hb was unmeasurable. We concluded that NO inhalation only partially reversed hypoxia-induced increases in pulmonary vasomotor tone in this canine model. These effects are immediate and selective to the pulmonary circulation.

Proximal pulmonary arterial obstruction decreases the time constant of the pulmonary circulation and increases right ventricular afterload

2013 ◽  
Vol 114 (11) ◽  
pp. 1586-1592 ◽  
Author(s):  
Alberto Pagnamenta ◽  
Rebecca Vanderpool ◽  
Serge Brimioulle ◽  
Robert Naeije
Keyword(s):  
Pulmonary Hypertension ◽  
Right Ventricular ◽  
Time Constant ◽  
Pulse Pressure ◽  
Pulmonary Circulation ◽  
Characteristic Impedance ◽  
Ventricular Afterload ◽  
Hydraulic Load ◽  
Distal Obstruction ◽  
Pulmonary Arterial

The time constant of the pulmonary circulation, or product of pulmonary vascular resistance (PVR) and compliance (Ca), called the RC-time, has been reported to remain constant over a wide range of pressures, etiologies of pulmonary hypertension, and treatments. We wondered if increased wave reflection on proximal pulmonary vascular obstruction, like in operable chronic thromboembolic pulmonary hypertension, might also decrease the RC-time and thereby increase pulse pressure and right ventricular afterload. Pulmonary hypertension of variable severity was induced either by proximal obstruction (pulmonary arterial ensnarement) or distal obstruction (microembolism) eight anesthetized dogs. Pulmonary arterial pressures (Ppa) were measured with high-fidelity micromanometer-tipped catheters, and pulmonary flow with transonic technology. Pulmonary ensnarement increased mean Ppa, PVR, and characteristic impedance, decreased Ca and the RC-time (from 0.46 ± 0.07 to 0.30 ± 0.03 s), and increased the oscillatory component of hydraulic load (Wosc/Wtot) from 25 ± 2 to 29 ± 2%. Pulmonary microembolism increased mean Ppa and PVR, with no significant change in Ca and characteristic impedance, increased RC-time from 0.53 ± 0.09 to 0.74 ± 0.05 s, and decreased Wosc/Wtot from 26 ± 2 to 13 ± 2%. Pulse pressure increased more after pulmonary ensnarement than after microembolism. Concomitant measurements with fluid-filled catheters showed the same functional differences between the two types of pulmonary hypertension, with, however, an underestimation of Wosc. We conclude that pulmonary hypertension caused by proximal vs. distal obstruction is associated with a decreased RC-time and increased pulsatile component of right ventricular hydraulic load.

Chronic hypercapnia inhibits hypoxic pulmonary vascular remodeling

2000 ◽  
Vol 278 (2) ◽  
pp. H331-H338 ◽  
Author(s):  
Henry Ooi ◽  
Elaine Cadogan ◽  
Michèle Sweeney ◽  
Katherine Howell ◽  
R. G. O'Regan ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Right Ventricular ◽  
Vascular Remodeling ◽  
Ventricular Hypertrophy ◽  
Chronic Hypoxia ◽  
Pulmonary Arterial Pressure ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Right Ventricular Hypertrophy ◽  
Pulmonary Vascular Remodeling ◽  
Pulmonary Arterial

Chronic hypercapnia is commonly found in patients with severe hypoxic lung disease and is associated with a greater elevation of pulmonary arterial pressure than that due to hypoxia alone. We hypothesized that hypercapnia worsens hypoxic pulmonary hypertension by augmenting pulmonary vascular remodeling and hypoxic pulmonary vasoconstriction (HPV). Rats were exposed to chronic hypoxia [inspiratory O2 fraction ([Formula: see text]) = 0.10], chronic hypercapnia (inspiratory CO2 fraction = 0.10), hypoxia-hypercapnia ([Formula: see text]= 0.10, inspiratory CO2 fraction = 0.10), or room air. After 1 and 3 wk of exposure, muscularization of resistance blood vessels and hypoxia-induced hematocrit elevation were significantly inhibited in hypoxia-hypercapnia compared with hypoxia alone ( P < 0.001, ANOVA). Right ventricular hypertrophy was reduced in hypoxia-hypercapnia compared with hypoxia at 3 wk ( P < 0.001, ANOVA). In isolated, ventilated, blood-perfused lungs, basal pulmonary arterial pressure after 1 wk of exposure to hypoxia (20.1 ± 1.8 mmHg) was significantly ( P < 0.01, ANOVA) elevated compared with control conditions (12.1 ± 0.1 mmHg) but was not altered in hypoxia-hypercapnia (13.5 ± 0.9 mmHg) or hypercapnia (11.8 ± 1.3 mmHg). HPV ([Formula: see text] = 0.03) was attenuated in hypoxia, hypoxia-hypercapnia, and hypercapnia compared with control ( P < 0.05, ANOVA). Addition of N ω-nitro-l-arginine methyl ester (10−4 M), which augmented HPV in control, hypoxia, and hypercapnia, significantly reduced HPV in hypoxia-hypercapnia. Chronic hypoxia caused impaired endothelium-dependent relaxation in isolated pulmonary arteries, but coexistent hypercapnia partially protected against this effect. These findings suggest that coexistent hypercapnia inhibits hypoxia-induced pulmonary vascular remodeling and right ventricular hypertrophy, reduces HPV, and protects against hypoxia-induced impairment of endothelial function.

E-4010, a selective phosphodiesterase 5 inhibitor, attenuates hypoxic pulmonary hypertension in rats

1999 ◽  
Vol 277 (2) ◽  
pp. L225-L232 ◽  
Author(s):  
Norihisa Hanasato ◽  
Masahiko Oka ◽  
Masashi Muramatsu ◽  
Mayu Nishino ◽  
Hideyuki Adachi ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Cardiac Output ◽  
Arterial Pressure ◽  
Right Ventricular ◽  
Ventricular Hypertrophy ◽  
Chronic Hypoxia ◽  
Systemic Arterial Pressure ◽  
Right Ventricular Hypertrophy ◽  
Pulmonary Arterial

The purpose of this study was to determine whether E-4010, a newly synthesized potent and selective orally active phosphodiesterase (PDE) 5 inhibitor, would prevent the development of chronic hypoxia-induced pulmonary hypertension in rats. In conscious, pulmonary hypertensive rats, a single oral administration of E-4010 (1.0 mg/kg) caused an acute, long-lasting reduction in mean pulmonary arterial pressure (PAP), with no significant effects on systemic arterial pressure, cardiac output, and heart rate. In rats that received food containing 0.01 or 0.1% E-4010 during the 3-wk exposure to hypoxia, mean PAP was significantly decreased (mean PAP 24.0 ± 0.9, 16.2 ± 0.8, and 12.8 ± 0.5 mmHg in rats treated with 0, 0.01, and 0.1% E-4010-containing food, respectively), whereas mean systemic arterial pressure was unchanged and cardiac output was slightly increased compared with chronically hypoxic control rats. Right ventricular hypertrophy, medial wall thickness in pulmonary arteries corresponding to the respiratory and terminal bronchioles, and the degree of muscularization of more distal arteries were less severe in E-4010-treated rats. Long-term treatment with E-4010 caused an increase in cGMP levels in lung tissue and plasma but not in aortic tissue and no significant change in cAMP levels in either lung, aorta, or plasma. These results suggest that long-term oral treatment with E-4010 reduced the increase in PAP, right ventricular hypertrophy, and pulmonary arterial remodeling induced by exposure to chronic hypoxia, probably through increasing cGMP levels in the pulmonary vascular smooth muscle.

Haemodynamic Variables during Repeated Exercise in Chronic Lung Disease

1978 ◽  
Vol 55 (5) ◽  
pp. 485-490
Author(s):  
F. Schrijen ◽  
V. Ježek
Keyword(s):  
Cardiac Output ◽  
Arterial Pressure ◽  
Right Ventricular ◽  
Lung Disease ◽  
Chronic Lung Disease ◽  
Systemic Arterial Pressure ◽  
Blood Gas ◽  
Repeated Exercise ◽  
Pulmonary Arterial ◽  
Rest And Exercise

1. Pulmonary and systemic haemodynamics during repeated exercise were studied in 28 patients with chronic lung disease of various etiology, 16 of whom suffered from chronic bronchitis. They performed a moderate exercise repeated after a 20 min rest period. Ventilatory variables, blood gas tensions, cardiac output and vascular pressures (right ventricular end-diastolic, pulmonary arterial, wedge and systemic arterial) were measured at rest, during exercise and again at rest and during the same exercise. 2. Ventilation and blood gas tensions were similar during the two rest and exercise periods; there was, however, a slightly significant difference in oxygen consumption and hydrogen ion concentration between the first and the second exercise period. Pulmonary arterial and wedge pressures were lower during the second rest and exercise, right ventricular filling pressure was lower at rest, and systemic arterial pressure during the second exercise. Cardiac output and pulmonary vascular resistance were unchanged. 3. Changes in systemic arterial pressure were significantly different in a group of patients with arterial oxygen desaturation or perfusion defects, compared with those patients without such impairment.

Nitric oxide inhalation: effects on the ovine neonatal pulmonary and systemic circulations

1996 ◽  
Vol 8 (3) ◽  
pp. 431 ◽  
Author(s):  
V DeMarco ◽  
JW Skimming ◽  
TM Ellis ◽  
S Cassin
Keyword(s):  
Nitric Oxide ◽  
Pulmonary Hypertension ◽  
Arterial Pressure ◽  
Pulmonary Circulation ◽  
Pulmonary Arterial Pressure ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Minimum Concentration ◽  
Pulmonary Vasoconstriction ◽  
Pulmonary Arterial ◽  
Inhaled No

Others have shown that inhaled nitric oxide causes reversal of pulmonary hypertension in anaesthetized perinatal sheep. The present study examined haemodynamic responses to inhaled NO in the normal and constricted pulmonary circulation of unanaesthetized newborn lambs. Three experiments were conducted on each of 7 lambs. First, to determine a minimum concentration of NO which could reverse acute pulmonary hypertension caused by infusion of the thromboxame mimic U46619, the haemodynamic effects of 5 different doses of inhaled NO were examined. Second, the effects of inhaling 80 ppm NO during hypoxic pulmonary vasoconstriction were examined. Finally, to determine if tachyphalaxis occurs during NO inhalation, lambs were exposed to 80 ppm NO for 3 h during which time pulmonary arterial pressure was doubled by infusion of U46619. Breathing NO (80 ppm) caused a slight but significant decrease in pulmonary vascular resistance (PVR) in lambs with normal pulmonary arterial pressure (PAP). Nitric oxide, inhaled at concentrations between 10 and 80 ppm for 6 min (F1O2 = 0.60), caused decreases in PVR when PAP was elevated with U46619. Nitric oxide acted selectively on the pulmonary circulation, i.e. no changes occurred in systemic arterial pressure or any other measured variable. Breathing 80 ppm NO for 6 min reversed hypoxic pulmonary vasoconstriction. In the chronic exposure study, inhaling 80 ppm NO for 3 h completely reversed U46619-induced pulmonary hypertension. Although arterial methaemoglobin increased during the 3-h exposure to 80 ppm NO, there was no indication that this concentration of NO impairs oxygen loading. These data demonstrate that NO, at concentrations as low as 10 ppm, is a potent, rapid-action, and selective pulmonary vasodilator in unanaesthetized newborn lambs with elevated pulmonary tone. Furthermore, these data support the use of inhaled NO for treatment of infants with pulmonary hypertension.

Pulmonary vascular impedance response to hypoxia in dogs and minipigs: effects of inhaled nitric oxide

1995 ◽  
Vol 79 (4) ◽  
pp. 1156-1162 ◽  
Author(s):  
M. Maggiorini ◽  
S. Brimioulle ◽  
D. De Canniere ◽  
M. Delcroix ◽  
P. Wauthy ◽  
...  
Keyword(s):  
Hypoxic Pulmonary Vasoconstriction ◽  
Characteristic Impedance ◽  
Low Frequency ◽  
Pulmonary Hemodynamics ◽  
Vascular Impedance ◽  
Impedance Response ◽  
Pulmonary Vasoconstriction ◽  
Pulmonary Arterial ◽  
Induced Changes ◽  
Inhaled No

The pig has been reported to present with a stronger hypoxic pulmonary vasoconstriction (HPV) than many other species, including dogs. We investigated [pulmonary arterial pressure (Ppa)-pulmonary arterial occluded pressure (Ppao)] vs. pulmonary blood flow (Q) relationships and pulmonary vascular impedance (PVZ) spectra in nine minipigs and nine weight-matched dogs. The animals were anesthetized and ventilated in hyperoxia [inspired O2 fraction 0.4] or hypoxia (inspired O2 fraction 0.12). PVZ was computed from the Fourier series for Ppa and Q. In hyperoxia, the pigs had a higher Ppa (26 +/- 1 vs. 16 +/- 1 mmHg), a higher first-harmonic impedance (Z1), and a more negative low-frequency phase angle but no different characteristic impedance (Zc) compared with the dogs at the same Q. Hypoxia in the dogs increased (Ppa-Ppao) at all levels of Q studied by an average of 2 mmHg but did not affect Z1 or Zc. Hypoxia in the pigs increased (Ppa-Ppao) at all levels of Q by an average of 13 mmHg and increased Z1 and Zc. Inhaled NO (150 ppm) reversed the hypoxia-induced changes in (Ppa-Ppao)/Q plots and PVZ in the dogs and pigs. However, differences in (Ppa-Ppao)/Q plots and PVZ between the dogs and pigs in hyperoxia and hypoxia were not affected by inhaled NO. We conclude 1) that minipigs present with an elevated pulmonary vascular resistance and impedance in hypoxia more than in hyperoxia and 2) that baseline differences in pulmonary hemodynamics between dogs and minipigs are structural rather than functional.

Vasomotor waves of arterial blood pressure after cessation of cardiopulmonary bypass in man

Perfusion ◽  
1990 ◽  
Vol 5 (4) ◽  
pp. 261-266
Author(s):  
V. Vainionpää ◽  
A. Hollme'n ◽  
J. Timisjärvi
Keyword(s):  
Blood Pressure ◽  
Cardiopulmonary Bypass ◽  
Arterial Pressure ◽  
Venous Pressure ◽  
Systemic Arterial Pressure ◽  
Heart Patients ◽  
Arterial Blood ◽  
Pulmonary Arterial ◽  
The Mean ◽  
Epicardial Pacing

The occurrence of vasomotor waves during cardiopulmonary bypass (CPB) is a recognized phenomenon. The lesser known oscillation of arterial pressure after cessation of CPB was observed in 18 open-heart patients. The duration of an oscillatory wave was 13.5±5.0 seconds, the amplitude 6.1 ±2.6mmNg and the mean arterial pressure 76.5± 10.7mmHg. Inter-and also intraindividual variations in frequency and amplitude of the oscillation, however, did occur. In 13 patients, this oscillation occurred during ventricular epicardial pacing. The oscillation continued until the end of the operation in eight patients; in others, the oscillation was of shorter duration. An oscillation of pulmonary arterial pressure (PAP) was simultaneously observed in nine patients (eight with pacemaker) and central venous pressure (CVP) oscillation in eight patients (all with pacemaker). The duration of a wave was the same as in systemic arterial pressure and the amplitudes were 1.5-3.0mmHg in PAP and 1.0-2.0mmHg in CVP. These arterial vasomotor waves, seen here after CPB, largely resemble those observed during perfusion in man and also the Mayerwaves explored in experimental animals. The pacing rhythm seems to favourthe appearance of those blood pressure oscillations.

scholarly journals Pulmonary Vasodilator Therapy in Children with Single Ventricle Physiology: Effects on Saturation and Pulmonary Arterial Pressure

2020 ◽  
Vol 41 (8) ◽  
pp. 1651-1659
Author(s):  
Ida Jeremiasen ◽  
Karin Tran-Lundmark ◽  
Nikmah Idris ◽  
Phan-Kiet Tran ◽  
Shahin Moledina
Keyword(s):  
Arterial Pressure ◽  
Single Ventricle ◽  
Pulmonary Arterial Pressure ◽  
Vasodilator Therapy ◽  
Single Ventricle Physiology ◽  
Pulmonary Vasodilators ◽  
Mean Pulmonary Arterial Pressure ◽  
Pulmonary Vasodilator ◽  
Pulmonary Arterial ◽  
Stage 1

AbstractIn children with single ventricle physiology, increased pulmonary vascular resistance may impede surgical progression or result in failing single ventricle physiology. The use of pulmonary vasodilators has been suggested as a potential therapy. However, knowledge on indication, dosage, and effect is limited. A retrospective case notes review of all (n = 36) children with single ventricle physiology, treated with pulmonary vasodilators by the UK Pulmonary Hypertension Service for Children 2004–2017. Therapy was initiated in Stage 1 (n = 12), Glenn (n = 8), or TCPC (n = 16). Treatment indications were high mean pulmonary arterial pressure, cyanosis, reduced exercise tolerance, protein-losing enteropathy, ascites, or plastic bronchitis. Average dose of sildenafil was 2.0 mg/kg/day and bosentan was 3.3 mg/kg/day. 56% had combination therapy. Therapy was associated with a reduction of the mean pulmonary arterial pressure from 19 to 14 mmHg (n = 17, p < 0.01). Initial therapy with one or two vasodilators was associated with an increase in the mean saturation from 80 to 85%, (n = 16, p < 0.01). Adding a second vasodilator did not give significant additional effect. 5 of 12 patients progressed from Stage 1 to Glenn, Kawashima, or TCPC, and 2 of 8 from Glenn to TCPC during a mean follow-up time of 4.7 years (0–12.8). Bosentan was discontinued in 57% and sildenafil in 14% of treated patients and saturations remained stable. Pulmonary vasodilator therapy was well tolerated and associated with improvements in saturation and mean pulmonary arterial pressure in children with single ventricle physiology. It appears safe to discontinue when no clear benefit is observed.

Mechanism and pharmacology of endotoxin shock in sheep

1963 ◽  
Vol 18 (3) ◽  
pp. 544-552 ◽  
Author(s):  
D. F. J. Halmagyi ◽  
B. Starzecki ◽  
G. J. Horner
Keyword(s):  
Cardiac Output ◽  
Arterial Pressure ◽  
Arterial Oxygen Saturation ◽  
Lung Compliance ◽  
Systemic Arterial Pressure ◽  
Endotoxin Shock ◽  
Arterial Oxygen ◽  
Marked Rise ◽  
Pulmonary Arterial ◽  
Pressure Fall

The cardiopulmonary consequences of coli-lipopolysaccharide and staphylococcus toxin administration were studied in sheep. Circulatory changes consisted mainly of a marked rise in pulmonary arterial and pulmonary arterial wedge pressure (with left atrial pressure unchanged), and a fall in cardiac output and in systemic arterial pressure. Fall in the latter closely followed the onset of pulmonary hypertension. The respiratory response consisted mainly of a severe fall in lung compliance produced by terminal airway closure. Continued perfusion of the nonventilated alveoli resulted in venous admixture. Premedication with antihistaminic, antiserotonin, or adrenolytic agents failed to affect the response. Norepinephrine or hypertensin administered after toxin injection had virtually no effect while isoproterenol treatment reduced pulmonary arterial pressure, increased cardiac output, arterial oxygen saturation, and, in cases of endotoxin shock, promptly raised systemic arterial pressure. Endotoxin-resistant sheep proved nonresponsive to minor pulmonary embolism and to incompatible blood transfusion. It is suggested that a common mediator agent is responsible for the similar cardiopulmonary consequences of these three diverse conditions. Submitted on November 26, 1962

Sign in / Sign up

Export Citation Format

Share Document