Effects of body position during cardiopulmonary exercise testing with right heart catheterization

Cardiopulmonary exercise testing (CPX) with right heart catheterization (RHC) widely used for early diagnosis and evaluation of pulmonary vascular disease in patients with pulmonary arterial hypertension and early stage heart failure with preserved ejection fraction, who display normal hemodynamics at rest. The aim of this study was to investigate that whether body position affects pulmonary hemodynamics, pulmonary arterial wedge pressure (PAWP), and CPX parameters during invasive CPX. Seventeen patients (58 +/- 14 years; 5/12 male/female) with chronic thromboembolic pulmonary hypertension treated with percutaneous transluminal pulmonary angioplasty and near-normal pulmonary artery pressure (PAP) underwent invasive CPX twice in supine and upright position using a cycle ergometer with 6 months interval. The mean PAP (peak: 45 +/- 7 vs. 40 +/- 11 mmHg, P = 0.006) and PAWP (peak: 17 +/- 4 vs. 11 +/- 7 mmHg, P = 0.008, supine vs. upright, respectively) throughout the test in supine position were significantly higher compared with in upright position, because of preload increase. However, transpulmonary pressure gradient, pulmonary vascular resistance, and mPA-Q slope during exercise were of no significant difference between two positions. There were no differences between the results of two positions in peak VO2 (15.9 +/- 4.0 vs. 16.6 +/- 3.2 mL/min per kg, P = 0.456), the VE versus VCO2 slope (37.8 +/- 9.2 vs. 35.9 +/- 8.0, P = 0.397), or the peak work-rate (79 +/- 29 vs. 84 +/- 27W, P = 0.118). Body position had a significant influence on PAP and PAWP during exercise, but no influence on the pulmonary circulation, or peak VO2, or VE vs.VCO2 slope.