Prognostic value of the post-training oxygen uptake efficiency slope in patients with coronary artery disease

Abstract

Background: Peak oxygen uptake is an independent predictor of mortality in patients with coronary artery disease (CAD). However, patients with CAD are not always capable of reaching peak effort, and therefore submaximal gas exchange variables such as the oxygen uptake efficiency slope (OUES) have been introduced. Baseline exercise capacity as expressed by OUES provides prognostic information and this parameter responds to training. Therefore, we aimed to assess the prognostic value of post-training OUES in patients with CAD. Methods: We included 960 patients with CAD (age 60.6 AE 9.5 years; 853 males) who completed a cardiac rehabilitation program between 2000 and 2011. The OUES was calculated before and after cardiac rehabilitation and information on mortality was obtained. The relationships of post-training OUES with all-cause and cardiovascular (CV) mortality was assessed by Cox proportional hazards regression analyses. Receiver operator characteristic curve analysis was performed in order to obtain the optimal cut-off value. Results: During 7.37 AE 3.20 years of follow-up (range: 0.45-13.75 years), 108 patients died, among whom 47 died due to CV reasons. The post-training OUES was related to all-cause (hazard ratio: 0.50, p < 0.001) and CV (hazard ratio: 0.40, p < 0.001) mortality. When significant covariates, including baseline OUES, were entered into the Cox regression analysis, post-training OUES remained related to all-cause and CV mortality (hazard ratio: 0.40, p < 0.01 and 0.26, p < 0.01, respectively). In addition, the change in OUES due to exercise training was positively related to mortality (hazard ratio: 0.49, p < 0.01). Conclusion: Post-training OUES has stronger prognostic value compared to baseline OUES. The lack of improvement in exercise capacity expressed by OUES after an exercise training program relates to a worse prognosis and can help distinguish patients with favorable and unfavorable prognoses.

The impact of high‐intensity interval training on ventricular remodeling in patients with a recent acute myocardial infarction—A randomized training intervention pilot study

“…Key CPET parameters like , OUES, and O 2 pulse (including O 2 pulse trajectory) are highly relevant predictors of mortality and morbidity in CHD patients . Structured exercise training regardless of training modality has proven to improve these parameters . However, in our study only patients in the HIIT group showed a substantial improvement and reached a normal age‐predicted after completion of the program with the identical level of exhaustion (ie, RER) as compared to the usual care group.…”

“…Key CPET parameters like , OUES, and O 2 pulse (including O 2 pulse trajectory) are highly relevant predictors of mortality and morbidity in CHD patients . Structured exercise training regardless of training modality has proven to improve these parameters .…”

“…4.1 | The impact of HIIT on CPET parametersKey CPET parameters like _ VO 2peak , OUES, and O 2 pulse (including O 2 pulse trajectory) are highly relevant predictors of mortality and morbidity in CHD patients [28][29][30]. Structured exercise training regardless of Baseline characteristics of CHD patients randomized to the HIIT or usual care group CPET parameters pre-and post-training in CHD patients randomized to the HIIT or usual care group…”

Cardiopulmonary Exercise Testing for Preoperative Evaluation: What Does the Future Hold?

“…Although encouraging, the data supporting the prognostic value of OUES is limited to date due to a lack of appropriately powered prospective studies and warrants further investigation. The OUES displays prognostic value in patients with HF [49][50][51] and coronary artery disease (CAD) [52,53] and has been shown to be responsive to physical training in patients with CAD [54,55].…”

Six years progression of exercise capacity in subjects with mild to moderate airflow obstruction, smoking and never smoking controls

“…1) The oxygen uptake efficiency slope (OUES) reflects the rate of increase of the logarithmically transformed ventilation in response to a given increase in oxygen uptake and it correlates highly with VO 2 peak in cross sectional studies [9]. The OUES is a prognostic marker in patients with chronic heart failure and coronary artery disease [10, 11], which both are common comorbidities of COPD [12]. 2) The ventilatory efficiency slope (ΔVE/ΔVCO 2 ), which represents the increase in ventilation for a given rise in carbon dioxide production, is increased when ventilation perfusion mismatching occurs, in case of diffusion abnormalities or with an excess dead space ventilation.…”