[Pulmonary arterial input impedance in patients with chronic pulmonary diseases]

To evaluate pulmonary vascular lesions, input impedance of pulmonary arterial system was determined in 52 patients with chronic pulmonary diseases (CPD) by using a multisensor catheter. Mean values of impedance parameters in 14 subjects with normal mean arterial pressure (less than 15 mmHg) were 31 +/- 3 dyne.sec.cm-5 in characteristic impedence (Zo), 3.5 +/- 0.3 Hz in the frequency at which the first minimum of the impedance modulus occurs (fmin) and 0.85 +/- 0.3 in Zx oscillation (Zxos). In patients with CPD, Zo increased with an elevation of pulmonary arterial pressure (p less than 0.01) and fmin shifted to the right with that (p less than 0.05). These results show that stiffness of the proximal arteries in CPD is increased. In patients of interstitial fibrosis with pulmonary arterial hypertension, Zo was not significantly increased, but fmin shifted to the right. Pulse wave velocity correlated with fmin, but did not correlate with Zo. In conclusion, these results suggest that analysis of pulmonary arterial input impedance with a multisensor catheter provides useful information for patients with pulmonary hypertension.