Noninvasive diagnosis of latent pulmonary hypertension in COPD by exercise-load impedance rheopneumogram: a comparative study with right heart catheterization.

Impedance rheopneumogram (IRP) and right heart Swan-Ganz catheter examinations were simultaneously carried out in 63 patients. Two equations for calculating after-exercise-pulmonary-pressure (PAPm) were obtained by stepwise regression analysis: 1) PAPm (kPa) = -1.40-0.88.InHs+8.30.(B-F)+5.78.Q-B/B-Y (r = 0.730, IRP is measured at rest); 2) PAPm(kPa) = 6.46-5.04.Hs/square root of R-R +4.35.Q-B/B-Y-19.34.(Q-C) (r = 0.648, IRP is measured after exercise). This is a new method for diagnosing latent pulmonary hypertension noninvasively.

[Hemodynamic changes and their relationship with the renin-angiotensin-aldosterone system in chronic obstructive pulmonary disease].

The hemodynamic changes and plasma renin activity (PRA), angiotensin II (ATII), aldosterone (Ald) levels in 38 COPD patients with or without pulmonary hypertension were studied. We found that the right ventricular pressure (RVP), pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR) and the levels of PRA, ATII, Ald increased significantly in patients with pulmonary hypertension when compared with those not accompanied by pulmonary hypertension. In addition, a close correlation was found between PRA, ATII, Ald and RVP, PAP, PVR. The relationship between ATII and PAP was very remarkable (r = 0.67, P less than 0.001). These findings suggest that the activation of renin-angiotensin-aldosterone system (RAAS) increases in COPD patients with pulmonary hypertension, and may involve in the development of pulmonary hemodynamic changes.