We read with great interest the report by Bursi et al. (1) on the prognostic value of pulmonary pressure in heart failure (HF). The investigators used Doppler-determined pulmonary artery systolic pressure (PASP), which requires an estimation of right atrial pressure by the diameter and respiratory variation of the inferior vena cava. This approach was initially followed to provide values comparable with those of right-heart catheterization. However, the almost arbitrary estimation of right atrial pressure and the use of reference values for PASP derived by right-heart catheterization worsen the reproducibility and reliability of Doppler measurements. We first identified this problem 15 years ago while studying pulmonary hypertension in beta-thalassemia, and we proposed the use of tricuspid regurgitant velocity and peak systolic tricuspid pressure gradient alone (2). To determine a reference range for tricuspid pressure gradient, we studied a group of healthy subjects and found an upper normal limit of 30 mm Hg, which corresponds to a tricuspid regurgitant velocity of 2.7 m/s (3). At present, tricuspid regurgitant velocity, with a threshold of 2.7 m/s, is the proposed method for the echocardiographic screening of pulmonary hypertension (3).

A tricky aspect in the echocardiographic evaluation of PASP in HF is the loading conditions at the time of examination (4). Patients with acute HF and lung congestion would have considerably high PASP reflecting the acutely increased left ventricular filling pressures, not the true, steady-state passive and active component of pulmonary hypertension. This parameter should be taken under consideration while evaluating patients with acute HF, and the examination should be repeated after clinical stabilization. Furthermore, it should be stressed that ejection fraction is a rough estimate of systolic left ventricular function, and this may account for the lack of association between PASP and systolic dysfunction severity observed by Bursi et al. (1).