Abstract
Non-invasive monitoring of haemodynamic responses during incremental cardiopulmonary exercise testing (CPET) could provide useful information on disease severity and prognosis in pulmonary arterial hypertension (PAH). Using an impedance cardiography (ICG) device that does not require basal impedance or blood resistivity estimations (PhysioFlow PF-05®, Manatec Biomedical, France), stroke volume (SV) and cardiac index (CI) were evaluated in 50 patients and 21 age- and gender-matched controls during a ramp-incremental CPET on a cycle ergometer. An ICG signal was not obtained in 5 patients and its quality was deemed as “poor” in another 7 patients, i.e., technical problems were found in 24% of the readings. Early decrease (N= 9) or a subsequent “plateau” in SV (N= 8) and Δ SV peak-unloaded exercise < 10 mL were found in more advanced PAH (p<0.05). A multiple logistic regression analysis revealed that ΔCI from rest ≤ 1.5-fold and oxygen uptake (V O2) at the gas exchange threshold were the only predictors of a severely-reduced peak V O2 (R2=0.71, p<0.001). In fact, peak V O2 < 50% predicted plus Δ CI < 1.5-fold were associated with other clinical and functional markers of disease severity and 1-year frequency of PAH-related adverse events (death and balloon atrial septostomy, N= 8; p<0.05). This study demonstrated that “qualitative” and “semi-quantitative” ICG might be useful to estimate disease severity and short-term prognosis in PAH patients in whom an acceptable impedance signal can be obtained.
Supported by: FAPESP, Brazil.
- © 2011 ERS