Abstract 17330: End-Tidal Carbon Dioxide Partial Pressure during Exercise, at the Anaerobic Threshold, is More Relevant Than Peak Oxygen Uptake in the Non-Invasive Evaluation of Scleroderma-Associated Pulmonary Hypertension
Background: Pulmonary arterial hypertension (PAH) is a well-known and fatal complication in patients (pts) with systemic sclerosis (SSc). Therefore, an early diagnosis of the disease is desirable. Cardiopulmonary exercise testing (CPET) is commonly used in the diagnostic workup of PAH. Peak oxygen consumption (peak VO2) is the most frequently measured parameter, and is recommended in the current European guidelines (European Society of Cardiology) for initial evaluation and non-invasive follow-up of PAH. Pathophysiological considerations suggest that exercise gas exchange parameters which reflect the matching of pulmonary ventilation to perfusion — in particular the end-tidal CO2 partial pressure (PETCO2) — are better able to evaluate early disease than a general marker of exercise limitation (peak VO2).
Methods: We prospectively evaluated 37 consecutively referred pts with SSC and dyspnea from our dermatology clinic. None of the pts had been previously diagnosed with PAH. Each patient underwent CPET, and right heart catheterization (RHC). PAH was diagnosed according to current guidelines by RHC.
Results: PAH could be confirmed in 20 and ruled out in 17 out of 37 cases. Sensitivity, specificity, positive / negative likelihood ratios as well as accuracy and precision are compared in table 1. PETCO2 at the anaerobic threshold (PETCO2@AT) was superior to peak VO2 in all analyzed parameters. Both peak VO2 and PETCO2@AT significantly correlated with hemodynamic parameters, whereas peak VO2 expressed as ml/kg/min showed more relevance than peakVO2 expressed as percentage of its predicted value. PETCO2@AT showed better correlations with hemodynamics than peak VO2 in all analyzed parameters.
Conclusions: PETCO2 during exercise was superior to peak VO2 in all relevant statistical indicators, and showed better correlation with measured hemodynamics. PETCO2 at the AT may be a more reliable parameter than peak VO2 for the evaluation of early PAH in this patient cohort.
- © 2010 by American Heart Association, Inc.