Oxygen Uptake Efficiency Slope and Breathing Reserve, Not Anaerobic Threshold, Discriminate Between Patients With Cardiovascular Disease Over Chronic Obstructive Pulmonary Disease

Abstract

ObjectivesThe study sought to compare the relative discrimination of various cardiopulmonary exercise testing (CPX) variables between cardiac and respiratory disease.BackgroundCPX 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.MethodsA total of 73 patients with chronic obstructive pulmonary 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 familiarization test, each patient underwent a personalized second test aiming for maximal exercise after ∼10 min. Measurements from this test were used to calculate area under the receiver-operator characteristic curve (AUC).ResultsPeak VO2 was similar between the 2 principal groups (COPD 17.1 ± 4.6 ml/min/kg; HFrEF 16.4 ± 3.6 ml/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 for AT as percent predicted peak VO2: 0.56). OUES and breathing reserve remained strong discriminators when compared with an external cohort of healthy matched controls, and were comparable to B-type natriuretic peptide.ConclusionsBreathing 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 while the VO2/WR slope showed poor to moderate discriminant ability. (Identifying an Ideal Cardiopulmonary Exercise Test Parameter [PVA]; NCT01162083)

Role of cardiopulmonary exercise testing in clinical stratification in heart failure. A position paper from the Committee on Exercise Physiology and Training of the Heart Failure Association of the European Society of Cardiology

“…Co‐morbidities are frequent in HFrEF, and are of great importance since they influence the cardiorespiratory response to exercise and (sometimes) outcome . In chronic obstructive pulmonary disease (COPD), if concomitant pulmonary vascular disease is excluded, the exertional CPET response is characterized by a normal VAT, a reduced breathing reserve and oxyhaemoglobin desaturation during and at the end of exercise.…”

“…In HFrEF patients with concomitant COPD, peak VO 2 is lower, and these patients show a shorter CPET duration, a lower peak VO 2 and are less likely to achieve a peak RER >1.10 . Lower breathing reserve and higher percent predicted VO 2 efficiency slope are also associated with COPD . The VE/VCO 2 slope in HF patients with concomitant COPD is peculiar and related to the severity of COPD …”

Pneumologisch relevante Daten aus der „Study of Health in Pomerania“ (SHIP) – eine Übersicht zu den Kohorten, Methoden und ersten Ergebnissen

“…Zusätzlich wurden sie für Assoziationsstudien genutzt (u. a. Blutdruck unter Belastung und Schilddrüsenfunktion: [43]; Endothelfunktion und Atemeffizienz: [44]; Belastungsfähigkeit und Insulin-like growth factor: [45]; Belastungsfähigkeit und Testosteron: [46]; Belastungsfähigkeit und Schilddrüsenfunktion: [30]; Belastungsfähigkeit und Vitamin D-Spiegel: [47]). Die Daten wurden zudem für die Erstellung einer Kontrollgruppe genutzt [48].…”

Oxygen uptake efficiency slope as a useful measure of cardiorespiratory fitness in morbidly obese women

“…OUES has been extensively applied in heart [13,14,19] or pulmonary disease [18,20,21], or both [22], and has revealed significantly lower OUES according to the disease severity. Reference equations for OUES have been proposed [23,24], however until now the use of OUES has not been established as a measure of cardiorespiratory fitness in an obese adult population.…”