Oxygen uptake efficiency slope and breathing reserve, not anaerobic threshold, discriminate between patients with cardiovascular disease over COPD
File(s)
Published version
Accepted version
Author(s)
Type
Journal Article
Abstract
Objectives To compare the relative discrimination of various cardiopulmonary exercise testing (CPX) variables between cardiac and respiratory disease.
Background CPX testing is used in many cardiorespiratory diseases. However discrimination of cardiac and respiratory dysfunction can be problematic. Anaerobic threshold (AT) and oxygen-uptake to work-rate relationship (VO2/WR slope) have been proposed as diagnostic of cardiac dysfunction, but multiple variables have not been compared.
Methods 73 patients with chronic obstructive airways disease (COPD, n=25), heart failure with reduced ejection fraction (HFrEF, n=40) or combined COPD and HFrEF (n=8), were recruited and underwent CPX testing on a bicycle ergometer. Following a familiarisation test, each patient underwent a personalised second test aiming for maximal exercise after ~10 minutes. Measurements from this test were used to calculate area under receiver-operator characteristic curve (AUC).
Results PeakVO2 was similar between the 2 principal groups (COPD 17.1±4.6ml/min/kg (mean±SD), HFrEF 16.4±3.6ml/min/kg). Breathing reserve (AUC 0.91) and percent predicted oxygen uptake efficiency slope (OUES) (AUC 0.87) had the greatest ability to discriminate between COPD and HFrEF. VO2/WR slope performed significantly worse (AUC 0.68). VO2 at the AT did not discriminate (AUC 0.56 for AT as percent predicted peakVO2). OUES and BR remained strong discriminators when compared with an external cohort of healthy matched controls, and were comparable to B-type natriuretic peptide.
Conclusions Breathing reserve and OUES discriminate heart failure from COPD. Despite it being considered an important determinant of cardiac dysfunction, the AT could not discriminate these typical clinical populations whilst the VO2/WR slope showed poor to moderate discriminant ability.
Background CPX testing is used in many cardiorespiratory diseases. However discrimination of cardiac and respiratory dysfunction can be problematic. Anaerobic threshold (AT) and oxygen-uptake to work-rate relationship (VO2/WR slope) have been proposed as diagnostic of cardiac dysfunction, but multiple variables have not been compared.
Methods 73 patients with chronic obstructive airways disease (COPD, n=25), heart failure with reduced ejection fraction (HFrEF, n=40) or combined COPD and HFrEF (n=8), were recruited and underwent CPX testing on a bicycle ergometer. Following a familiarisation test, each patient underwent a personalised second test aiming for maximal exercise after ~10 minutes. Measurements from this test were used to calculate area under receiver-operator characteristic curve (AUC).
Results PeakVO2 was similar between the 2 principal groups (COPD 17.1±4.6ml/min/kg (mean±SD), HFrEF 16.4±3.6ml/min/kg). Breathing reserve (AUC 0.91) and percent predicted oxygen uptake efficiency slope (OUES) (AUC 0.87) had the greatest ability to discriminate between COPD and HFrEF. VO2/WR slope performed significantly worse (AUC 0.68). VO2 at the AT did not discriminate (AUC 0.56 for AT as percent predicted peakVO2). OUES and BR remained strong discriminators when compared with an external cohort of healthy matched controls, and were comparable to B-type natriuretic peptide.
Conclusions Breathing reserve and OUES discriminate heart failure from COPD. Despite it being considered an important determinant of cardiac dysfunction, the AT could not discriminate these typical clinical populations whilst the VO2/WR slope showed poor to moderate discriminant ability.
Date Issued
2016-02-10
Date Acceptance
2015-11-03
Citation
JACC: Heart Failure, 2016, 4 (4), pp.252-261
ISSN
2213-1779
Publisher
Elsevier
Start Page
252
End Page
261
Journal / Book Title
JACC: Heart Failure
Volume
4
Issue
4
Copyright Statement
Open Access funded by British Heart Foundation
Sponsor
British Heart Foundation
British Heart Foundation
Grant Number
PG/11/36/28883
FS/10/38/28268
Subjects
cardiopulmonary exercise testing
chronic heart failure
exercise physiology
obstructive pulmonary disease
Publication Status
Published