Usefulness of decrease in oxygen uptake efficiency slope to identify myocardial perfusion defects in men undergoing...

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.