Utility of the oxygen pulse in the diagnosis of obstructive coronary artery disease in physically fit patients

Cardiopulmonary exercise testing (CPET) guidelines recommend analysis of the oxygen (O(2)) pulse for a late exercise plateau in evaluation for obstructive coronary artery disease (OCAD). However, whether this O(2) pulse trajectory is within the range of normal has been debated, and the diagnostic performance of the O(2) pulse for OCAD in physically fit individuals, in whom [Formula: see text] may be more likely to plateau, has not been evaluated. Using prospectively collected data from a sports cardiology program, patients were identified who were free of other cardiac disease and underwent clinically‐indicated CPET within 90 days of invasive or computed tomography coronary angiography. The diagnostic performance of quantitative O(2) pulse metrics (late exercise slope, proportional change in slope during late exercise) and qualitative assessment for O(2) pulse plateau to predict OCAD was assessed. Among 104 patients (age:56 ± 12 years, 30% female, peak [Formula: see text] 119 ± 34% predicted), the diagnostic performance for OCAD (n = 24,23%) was poor for both quantitative and qualitative metrics reflecting an O(2) pulse plateau (late exercise slope: AUC = 0.55, sensitivity = 68%, specificity = 41%; proportional change in slope: AUC = 0.55, sensitivity = 91%, specificity = 18%; visual plateau/decline: AUC = 0.51, sensitivity = 33%, specificity = 67%). When O(2) pulse parameters were added to the electrocardiogram, the change in AUC was minimal (−0.01 to +0.02, p ≥ 0.05). Those patients without OCAD with a plateau or decline in O(2) pulse were fitter than those with linear augmentation (peak [Formula: see text] 133 ± 31% vs. 114 ± 36% predicted, p < 0.05) and had a longer exercise ramp time (9.5 ± 3.2 vs. 8.0 ± 2.5 min, p < 0.05). Overall, a plateau in O(2) pulse was not a useful predictor of OCAD in a physically fit population, indicating that the O(2) pulse should be integrated with other CPET parameters and may reflect a physiologic limitation of stroke volume and/or O(2) extraction during intense exercise.