Abstract 13580: Gas Exchange Measurements During Exercise Significantly Correlate with Hemodynamics in Patients with Scleroderma-Associated Pulmonary Arterial Hypertension
RATIONALE: Pulmonary arterial hypertension (PAH) is a well-known complication in patients (pts) with scleroderma (SSc), harbouring a poor prognosis. While the disease is diagnosed by right heart catheterization (RHC), the follow-up evaluation is primarily based on non-invasive diagnostic procedures. Here, we analyzed whether gas exchange parameters during maximal and submaximal exercise correlate with hemodynamics. From pathophysiological considerations, we hypothesized that gas exchange parameters would significantly reflect impaired hemodynamics.
METHODS: We analyzed 45 consecutive SSc pts with dyspnea. None of the pts had been diagnosed with PAH. Each patient underwent right heart catheterization (RHC) at rest and cardiopulmonary exercise testing (CPET). PAH was diagnosed according to current guidelines (PAPmean ≥ 25 mmHg, PCWP ≤ 15 mmHg).
RESULTS: In 22 out of 45 cases, PAH was diagnosed by RHC and could be ruled out in 23 cases. We correlated hemodynamics to gas exchange. The detailed results are shown in table 1. In patients with and without PAH, almost all gas exchange parameters correlated to pulmonary vascular hemodynamics. Peak VO2, corrected for body weight was superior to peak VO2 displayed as percent of the predicted value. The anaerobic threshold (AT), ventilatory equivalents for CO2(VE/VCO2) and end-tidal CO2 partial pressure (PETCO2) correlated best with each hemodynamic parameter.
CONCLUSIONS: Gas exchange measurements are not able to replace hemodynamic measurements. Peak VO2 should be corrected for body weight rather than regarding the value as percent of predicted. Regarding evaluation of PAH, the AT as well as parameters reflecting ventilation/perfusion matching are best suitable for the non-invasive work-up of SSc patients. Serial measurements are necessary to determine whether changes in the individual hemodynamic status are accurately reflected by gas exchange.
- © 2012 by American Heart Association, Inc.