EFFECT OF INCREASED RIGHT-VENTRICULAR PRELOAD ON PULMONARY-ARTERY FLOW VELOCITY PATTERN IN PATIENTS WITH NORMAL OR INCREASED PULMONARY-ARTERY PRESSURE - A SIMULTANEOUS DOPPLER AND SWAN-GANZ CATHETER STUDY

Evaluation of the pulmonary artery flow velocity pattern with Doppler echocardiography is widely used for noninvasive evaluation of pulmonary artery pressure although the influence of variables other than pulmonary artery pressure on the characteristics of right ventricular ejection has not been clarified. To assess the relationship between right ventricular preload and ejection pattern 26 male patients (mean age 61 +/- 8 years) with chronic obstructive pulmonary disease were evaluated with simultaneous right heart catheterization and an echo-Doppler study before and during passive leg raising (PLR). 16 patients had pulmonary hypertension [PH; pulmonary artery mean pressure (PAP) 30.3 +/- 6.5 mm Hg] and 10 had normal pulmonary artery mean pressure (PN; 17.0 +/- 1.9 mm Hg). There was no change in heart rate and pulmonary vascular resistance but PLR resulted in an increase in right atrial pressure, pulmonary wedge pressure; total pulmonary resistance and pulmonary flow. Despite a similar rise of PAP in PH (by 6.5 mm Hg, i.e. 22%) and in PN (by 4.6 mm Hg, i.e. 27%) pulmonary artery acceleration time (AcT) was shortened only in PH (from 77.9 +/- 11.8 to 74.1 +/- 10.5 ms; p = 0.001) whereas showing an opposite trend in PN (from 96.9 +/- 20 to 99.9 +/- 12.4 ms, nonsignificant). The slope of the linear relationship between AcT and PAP was significantly different (p < 0.0001) before and after PLR. The preservation of the baseline duration of AcT during PLR in patients with initially normal PAP may be due to more compliant pulmonary artery and/or better right ventricular systolic performance in comparison to patients with pulmonary hypertension. The right ventricular ejection pattern is not directly dependent on pulmonary artery pressure, which should be realized while using AcT as a noninvasive estimate of PAP.