Exercise capacity reflects airflow limitation rather than hypoxaemia in patients with pulmonary arteriovenous malformations
File(s)Gawecki et al QJM 2019 as accepted.pdf (847.85 KB)
Accepted version
Author(s)
Type
Journal Article
Abstract
Background: Pulmonary arteriovenous malformations (PAVMs) generate a right-to-left shunt. Impaired gas exchange results in hypoxemia and impaired CO2 clearance. Most patients compensate effectively but a proportion are dyspneic, and these are rarely the most hypoxaemic. Aim: To test degrees of concurrent pathology influencing exercise capacity. Design: Replicate, sequential single centre, prospective studies. Methods: Cardiopulmonary exercise tests (CPET) were performed in 26 patients with PAVMs, including individuals with and without known airflow obstruction. To replicate, relationships were tested prospectively in an independent cohort where self-reported exercise capacity evaluated by the Veterans Specific Activity Questionnaire (VSAQ) was used to calculate metabolic equivalents at peak exercise (METS N = 71). Additional measurements included oxygen saturation (SpO2), forced expiratory volume in 1 second (FEV1), vital capacity (VC), exhaled nitric oxide (FeNO), haemoglobin and iron indices. Results: By CPET, the peak work-rate was only minimally associated with low SpO2 or low arterial oxygen content (CaO2=1.34 x SpO2 x haemoglobin), but was reduced in patients with low FEV1 or VC. Supranormal work-rates were seen in patients with severe right-to-left shunting and SpO2 <90%, but only if FEV1 was >80% predicted. VSAQ-calculated METS also demonstrated little relationship with SpO2, and in crude and CaO2-adjusted regression, were lower in patients with lower FEV1 or VC. Bronchodilation increased airflow even where spirometry was in the normal range: exhaled nitric oxide measurements were normal in 80% of cases, and unrelated to any PAVM-specific variable. Conclusions: Exercise capacity is reduced by relatively mild airflow limitation (obstructive or restrictive) in the setting of PAVMs.
Date Issued
2019-05
Online Publication Date
2020-01-17T07:00:22Z
Date Acceptance
2018-12-23
ISSN
1460-2393
Publisher
Oxford University Press (OUP)
Start Page
335
End Page
342
Journal / Book Title
QJM: An International Journal of Medicine
Volume
112
Issue
5
Copyright Statement
© 2019 Oxford University Press. This is a pre-copy-editing, author-produced version of an article accepted for publication in [insert journal title] following peer review. The definitive publisher-authenticated version QJM: An International Journal of Medicine, hcz023, is available online at: https://dx.doi.org/10.1093/qjmed/hcz023
Source Database
pubmed
Identifier
https://academic.oup.com/qjmed/article/112/5/335/5290088
https://www.ncbi.nlm.nih.gov/pubmed/30657990
5290088
Subjects
Science & Technology
Life Sciences & Biomedicine
Medicine, General & Internal
General & Internal Medicine
EXHALED NITRIC-OXIDE
TO-LEFT SHUNT
ACTIVITY QUESTIONNAIRE
EMBOLIZATION
TOLERANCE
STATEMENT
Adolescent
Adult
Aged
Aged, 80 and over
Arteriovenous Malformations
Exercise Test
Exercise Tolerance
Female
Forced Expiratory Volume
Humans
Hypoxia
Linear Models
Lung
Male
Middle Aged
Prospective Studies
Pulmonary Artery
Pulmonary Veins
Spirometry
Vital Capacity
Young Adult
Lung
Pulmonary Artery
Pulmonary Veins
Humans
Arteriovenous Malformations
Exercise Test
Vital Capacity
Forced Expiratory Volume
Spirometry
Linear Models
Prospective Studies
Exercise Tolerance
Adolescent
Adult
Aged
Aged, 80 and over
Middle Aged
Female
Male
Young Adult
Hypoxia
General & Internal Medicine
11 Medical and Health Sciences
Publication Status
Published
Country
England
Article Number
hcz023
Date Publish Online
2019-01-17