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



We included 960 patients with CAD (age 60.6 ± 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.



During 7.37 ± 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).



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.
Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium roselien.buys@faber.kuleuven.be.
Roselien
R
Buys
Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
Ellen
E
Coeckelberghs
Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
Véronique A
VA
Cornelissen
Department of Cardiovascular Diseases, University Hospitals of Leuven, Leuven, Belgium.
Kaatje
K
Goetschalckx
Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
Luc
L
Vanhees
D000072038:Cardiac Rehabilitation / Q000379:methods*; D003324:Coronary Artery Disease / Q000378:metabolism / Q000503:physiopathology / Q000534:rehabilitation*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen; D010101:Oxygen Consumption / Q000502:physiology*; D011379:Prognosis; D012372:ROC Curve; D012189:Retrospective Studies
D010100:Oxygen
Coronary artery disease; cardiac rehabilitation; mortality; oxygen uptake efficiency slope