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Updated: Jun 6, 2026
Oxygenation-sensitive Cardiac MRI with Vasoactive Breathing Maneuvers for the Non-invasive Assessment of Coronary Microvascular Dysfunction
Published on: August 17, 2022
Usefulness of decrease in oxygen uptake efficiency slope to identify myocardial perfusion defects in men undergoing
Sherry Pinkstaff1, Mary Ann Peberdy, Michael C Kontos
1Department of Physical Therapy, Virginia Commonwealth University, Medical College of Virgínia Campus, Richmond, Virginia.
Insights
A negative change in oxygen uptake efficiency slope (OUES) during cardiopulmonary exercise testing (CPX) predicts coronary artery disease in men. This ventilatory efficiency metric shows diagnostic value, particularly in identifying significant perfusion defects.
Area of Science:
- Cardiology
- Exercise Physiology
- Diagnostic Imaging
Background:
- Cardiopulmonary exercise testing (CPX) is a potential tool for diagnosing coronary artery disease (CAD).
- Previous studies have not extensively evaluated a diverse patient population or a comprehensive set of CPX variables.
Purpose of the Study:
- To investigate the diagnostic utility of CPX variables, specifically ventilatory efficiency, in identifying CAD.
- To assess the predictive value of changes in the oxygen uptake efficiency slope (OUES) for myocardial perfusion study (MPS) findings.
Main Methods:
- 303 subjects with suspected CAD underwent CPX and single photon emission computed tomographic myocardial perfusion study (MPS).
- Ventilatory efficiency was assessed using the oxygen uptake efficiency slope (OUES).
- The change in OUES was calculated by comparing the first 50% and last 25% of CPX.
Main Results:
- A negative change in OUES (< 0) predicted positive MPS findings exclusively in male subjects.
- The diagnostic accuracy for any positive MPS finding in men was significant (AUC 0.67).
- Diagnostic accuracy was stronger for definitive perfusion defects (AUC 0.76, RR 5.4).
Conclusions:
- A change in ventilatory efficiency, measured by OUES, is a novel predictor of positive MPS findings.
- The diagnostic utility of OUES change is specific to male patients, necessitating further investigation.
- CPX-derived ventilatory efficiency offers valuable, sex-specific insights into CAD diagnosis.
Abstract:
Cardiopulmonary exercise testing (CPX) might aid in the diagnosis of coronary artery disease. However, a heterogeneous clinical population without previous workup bias has not been studied nor has a more extensive list of CPX variables. A total of 303 subjects (age 49.9 ± 11.6 years, 157 men) with symptoms suggestive of coronary artery disease underwent CPX and a single photon emission computed tomographic myocardial perfusion study (MPS). Ventilatory efficiency was calculated using the oxygen uptake efficiency slope (OUES). The change in the OUES was calculated by subtracting the OUES response during the first 50% of CPX from the OUES obtained during the last 25% of CPX. A negative change in the OUES (< 0) from the first 50% to the last 25% of CPX was predictive of positive MPS findings only in the male subjects. The diagnostic significance of the change in OUES in men was found for any level (including equivocal studies) of positive MPS findings (area under the curve 0.67, 95% confidence interval 0.59 to 0.76, p < 0.0001) and was even stronger in those with a more definitive (excluding equivocal studies) perfusion defect (area under the curve 0.76, 95% confidence interval 0.67 to 0.85; relative risk 5.4, 95% confidence interval 2.1 to 13.8, p < 0.0001). In conclusion, this is the first time that a change in ventilatory efficiency, assessed using the OUES, has been shown to be predictive of positive MPS findings However, the OUES change only provided diagnostic information for men, a finding that warrants additional analysis.
