Abstract
Background
Peak exercise oxygen uptake (peakVo2) is a widely used prognosticator. Novel spirometric parameters, less affected by submaximal performance, such as the rate of increase of minute ventilation per unit decrease of carbon dioxide production (VE/Vco2 slope) and the oxygen uptake efficiency slope (OUES) have recently been introduced.
Aim
To evaluate the discriminative value of OUES, as compared to VE/Vco2 slope in patients with coronary artery disease (CAD) and intermediate peakVo2 values.
Methods and results
Bicycle spiroergometry was applied in 214 patients with CAD (age 67 ± 8 years, 85% men). OUES was strongly related to peakVo2 (r = 0.79). New York Heart Association (NYHA) class, 6-min walking distance, N-terminal probrain natriuretic peptide (NT-proBNP), inflammatory markers, left ventricular (LV) volumes and ejection fraction were evaluated. NT-proBNP levels predicted independently VE/Vco2-slope and OUES. Patients with intermediate peakVo2 (12–18 ml/kg per min) and increased VE/Vco2-slope (≥ 35) had higher NYHA class, lower walking distance, higher NT-proBNP levels and higher LV volumes as compared to patients with a similar peakVo2 but lower VE/Vco2-slope. Similar findings were found for patients with intermediate peakVo2 and high OUES/kg (median value > 15.3).
Conclusion
In CAD patients, OUES was strongly correlated with peakVo2. Both VE/Vco2 slope and OUES were independently associated with NT-proBNP levels. Both VE/Vco2 slope and OUES/kg were able to identify a subgroup of patients with an intermediate peakVo2 that was characterized by advanced remodelling and a higher degree of neurohumoral activation.
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