VE/Vco(2) slope and oxygen uptake efficiency slope in patients with coronary artery disease and intermediate peakVo(2)

Background Peak exercise oxygen uptake (peak Vo(2)) 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/Vco(2) slope) and the oxygen uptake efficiency slope (OUES) have recently been introduced.

Aim To evaluate the discriminative value of OUES, as compared to VE/Vco(2) slope in patients with coronary artery disease (CAD) and intermediate peakVo(2) values.

Methods and results Bicycle spiroergometry was applied in 214 patients with CAD (age 67 +/- 8 years, 85% men). OUES was strongly related to peakVo(2) (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/Vco(2)-Slope and CUES. Patients with intermediate peakVo(2) (12 - 18 ml/kg per min) and increased VE/Vco(2)-slope (>= 35) had higher NYHA class, lower walking distance, higher NT-proBNP levels and higher LV volumes as compared to patients with a similar peakVo(2) but lower VE/Vco(2)-Slope. Similar findings were found for patients with intermediate peakVo(2) and high OUES/kg (median value > 15.3).

Conclusion In CAD patients, OUES was strongly correlated with peakVo(2). Both VE/Vco(2) slope and OUES were independently associated with NT-proBNP levels. Both VE/Vco(2) slope and OUES/kg were able to identify a subgroup of patients with an intermediate peakVo(2) that was characterized by advanced remodelling and a higher degree of neurohumoral activation.