scholarly journals Simultaneous Measurement of Lung Diffusing Capacity and Pulmonary Hemodynamics Reveals Exertional Alveolar‐Capillary Dysfunction in Heart Failure With Preserved Ejection Fraction

2021 ◽  
Author(s):  
Caitlin C. Fermoyle ◽  
Glenn M. Stewart ◽  
Barry A. Borlaug ◽  
Bruce D. Johnson
Keyword(s):  
Heart Failure ◽  
Maximal Exercise ◽  
Arterial Compliance ◽  
Preserved Ejection Fraction ◽  
Diffusing Capacity ◽  
Pulmonary Capillary ◽  
Capillary Membrane ◽  
Pulmonary Arterial ◽  
Wedge Pressure ◽  
Alveolar Capillary

Background Hemodynamic perturbations in heart failure with preserved ejection fraction (HFpEF) may alter the distribution of blood in the lungs, impair gas transfer from the alveoli into the pulmonary capillaries, and reduce lung diffusing capacity. We hypothesized that impairments in lung diffusing capacity for carbon monoxide (DL CO ) in HFpEF would be associated with high mean pulmonary capillary wedge pressures during exercise. Methods and Results Rebreathe DL CO and invasive hemodynamics were measured simultaneously during exercise in patients with exertional dyspnea. Pulmonary pressure waveforms and breath‐by‐breath pulmonary gas exchange were recorded at rest, 20 W, and symptom‐limited maximal exercise. Patients with HFpEF (n=20; 15 women, aged 65±11 years, body mass index 36±8 kg/m 2 ) achieved a lower symptom‐limited maximal workload (52±27 W versus 106±42 W) compared with controls with noncardiac dyspnea (n=10; 7 women, aged 55±10 years, body mass index 30±5 kg/m 2 ). DL CO was lower in patients with HFpEF compared with controls at rest (DL CO 10.4±2.9 mL/min per mm Hg versus 16.4±6.9 mL/min per mm Hg, P <0.01) and symptom‐limited maximal exercise (DL CO 14.6±4.7 mL/min per mm Hg versus 23.8±10.8 mL/min per mm Hg, P <0.01) because of a lower alveolar‐capillary membrane conductance in HFpEF (rest 16.8±6.6 mL/min per mm Hg versus 28.4±11.8 mL/min per mm Hg, P <0.01; symptom‐limited maximal exercise 25.0±6.7 mL/min per mm Hg versus 45.5±22.2 mL/min per mm Hg, P <0.01). DL CO was lower in HFpEF for a given mean pulmonary artery pressure, mean pulmonary capillary wedge pressure, pulmonary arterial compliance, and transpulmonary gradient. Conclusions Lung diffusing capacity is lower at rest and during exercise in HFpEF due to impaired gas conductance across the alveolar‐capillary membrane. DL CO is impaired for a given pulmonary capillary wedge pressure and pulmonary arterial compliance. These data provide new insight into the complex relationships between hemodynamic perturbations and gas exchange abnormalities in HFpEF.

Pulmonary diffusing capacity and capillary blood volume in normal and anemic dogs

1965 ◽  
Vol 20 (1) ◽  
pp. 113-116 ◽  
Author(s):  
Denise Jouasset-Strieder ◽  
John M. Cahill ◽  
John J. Byrne ◽  
Edward A. Gaensler
Keyword(s):  
Blood Volume ◽  
Capillary Blood ◽  
Diffusing Capacity ◽  
Alveolar Volume ◽  
Arterial Blood ◽  
Pulmonary Capillary ◽  
Capillary Membrane ◽  
Capillary Blood Volume ◽  
The Mean ◽  
Alveolar Capillary

The CO diffusing capacity (Dl) was measured by the single-breath method in eight anesthetized dogs. Pulmonary capillary blood volume (Vc) and membrane diffusing capacity (Dm) were determined in six animals by the method of Roughton and Forster. The studies were repeated after anemia had been induced by replacing whole blood with plasma. Large dogs were selected with a mean body weight of 29 kg and a mean alveolar volume of 2,020 ml (STPD) during tests. The mean arterial blood Hb decreased from 14.3 to 6.6 g/100 ml, the mean Dl from 27 to 12 ml/min mm Hg, and the mean Dm from 100 to 47 ml/min mm Hg. Vc averaged 67 ml in the control state and was not significantly changed during anemia. Reductions in Dl and Dm during anemia were proportional to the fall in blood Hb. Both Dl and Dm in all dogs, normal and anemic, were proportional to the volume of red blood cells in the lung capillaries (Vrbc). These results suggest that Vrbc might be an estimate of the useful area of the alveolar-capillary membrane while Dm/Vrbc should vary with changes in its thickness. The latter was not altered by anemia. alveolar capillary membrane; pulmonary membrane; diffusing capacity; pulmonary capillary RBC volume; pulmonary diffusion pathway; carbon monoxide Submitted on March 2, 1964

Improvement of Alveolar–Capillary Membrane Diffusing Capacity With Enalapril in Chronic Heart Failure and Counteracting Effect of Aspirin

Circulation ◽  
1997 ◽  
Vol 95 (7) ◽  
pp. 1930-1936 ◽  
Author(s):  
Marco Guazzi ◽  
Giancarlo Marenzi ◽  
Marina Alimento ◽  
Mauro Contini ◽  
Piergiuseppe Agostoni
Keyword(s):  
Heart Failure ◽  
Chronic Heart Failure ◽  
Diffusing Capacity ◽  
Capillary Membrane ◽  
Alveolar Capillary

scholarly journals Effects of exercise on thoracic blood volumes, lung fluid accumulation, and pulmonary diffusing capacity in heart failure with preserved ejection fraction

2020 ◽  
Vol 319 (5) ◽  
pp. R602-R609
Author(s):  
Caitlin C. Fermoyle ◽  
Glenn M. Stewart ◽  
Barry A. Borlaug ◽  
Bruce D. Johnson
Keyword(s):  
Membrane Conductance ◽  
Submaximal Exercise ◽  
Preserved Ejection Fraction ◽  
Diffusing Capacity ◽  
Fluid Accumulation ◽  
Fluid Content ◽  
Lung Fluid ◽  
Capillary Membrane ◽  
Alveolar Capillary ◽  
Blood Volumes

Patients with heart failure with preserved ejection fraction (HFpEF) experience symptoms of exertional dyspnea that may be related to lung fluid accumulation during exercise. A computed tomography (CT)-based method was used to measure exercise-induced changes in extravascular lung fluid content and thoracic blood volumes and to determine the effect of lung fluid on lung diffusing capacity for carbon monoxide (DLCO) in stable subjects with HFpEF and healthy controls. Nine subjects with HFpEF (age = 68 ± 8 yr; body mass index = 32.1 ± 2.6 kg/m2) and eight healthy controls (62 ± 9 yr, 23.8 ± 2.4 kg/m2) performed triplicate rebreathe DLCO/DLNO (lung diffusing capacity for nitric oxide) tests in a supine position at rest and duplicate measurements during two 5-min submaximal exercise stages (15W and 35W) and recovery. Subjects subsequently performed a 5-min exercise bout (35W) inside a CT scanner, and extravascular lung fluid content and thoracic blood volumes were quantified at rest and immediately following exercise from thoracic and contrast perfusion scans, respectively. Subjects with HFpEF had a higher lung fluid content at rest compared with controls (means ± SD, HFpEF: 14.4 ± 1.7%, control: 12.8 ± 1.7%, P = 0.043) and a higher lung fluid content following exercise (15.2 ± 2.0% vs. 12.6 ± 1.5%, P = 0.009). Higher lung fluid content was associated with a lower DLCO and alveolar-capillary membrane conductance (Dm) in subjects with HFpEF (DLCO: R = −0.57, P = 0.022, Dm: R = −0.61, P = 0.012) but not in controls. Pulmonary blood volume was not altered by exercise and was similar between groups. Submaximal exercise elicited a greater accumulation of lung fluid in subjects with HFpEF compared with in controls, and lung fluid content was negatively correlated with lung diffusing capacity and alveolar-capillary membrane conductance in subjects with HFpEF.

scholarly journals Pathophysiologic importance of visceral adipose tissue in women with heart failure and preserved ejection fraction

2020 ◽  
Author(s):  
Hidemi Sorimachi ◽  
Masaru Obokata ◽  
Naoki Takahashi ◽  
Yogesh N V Reddy ◽  
Christopher C Jain ◽  
...  
Keyword(s):  
Heart Failure ◽  
Adipose Tissue ◽  
Ejection Fraction ◽  
Visceral Adipose Tissue ◽  
Preserved Ejection Fraction ◽  
Similar Extent ◽  
Pulmonary Capillary ◽  
Tissue Area ◽  
Visceral Adipose ◽  
Wedge Pressure

Abstract Aims  Central obesity is a major risk factor for heart failure with preserved ejection fraction (HFpEF), particularly in women, but the mechanisms remain unclear. We hypothesized that sex-specific differences in visceral adipose tissue (VAT) content would differentially relate to haemodynamic severity of HFpEF in women and men. Methods and results  Abdominal computed tomography (CT) and invasive haemodynamic exercise testing were performed in 105 subjects with HFpEF (63 women) and 105 age-, sex-, and body mass index-matched controls. Visceral adipose tissue area was quantified by CT. As compared with control women, VAT area was 34% higher in women with HFpEF (186 ± 112 vs. 139 ± 72 cm2, P = 0.006), while VAT area was not significantly different in men with or without HFpEF (294 ± 158 vs. 252 ± 92 cm2, P = 0.1). During exercise, pulmonary capillary wedge pressure (PCWP) increased markedly and to similar extent in both men and women with HFpEF. Women with increased VAT area displayed 33% higher PCWP during exercise compared with women with normal VAT area (28 ± 10 vs. 21 ± 10 mmHg, P = 0.001), whereas exercise PCWP was similar in men with or without excess VAT (24 ± 9 vs. 25 ± 6, P = 0.89). In women, each 100 cm2 increase in VAT area was associated with a 4.0 mmHg higher PCWP (95% CI 2.1, 6.0 mmHg; P &lt; 0.0001), but there was no such relationship in men (interaction P = 0.009). Conclusions  These data suggest that accumulation of excess VAT plays a distinct and important role in the pathophysiology of HFpEF preferentially in women. Further research is needed to better understand the mechanisms and treatment implications for visceral fat in HFpEF.

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