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

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.