Doppler Estimation of Pulmonary Artery Systolic Pressure Revisited

Previous attempts at noninvasive estimation of pulmonary artery systolic pressure (PA_S) were limited by the inability to identify adequate spectral signals of tricuspid regurgitation (TR) in a significant proportion of patients. Recently, image and color flow directed continuous-wave Doppler have enabled spectral mapping of previously undetectable TR jets. Accordingly, 30 consecutive patients underwent two-dimensional and continuous-wave Doppler echocardiograms immediately before right heart catheterization. PA_S was calculated as ∑ (4V²+ RA) where Vis the maximal velocity of the TR jet in ml sec and RA is right atrial pressure as estimated by the caval respiratory index. Twenty-eight patients (93%) had detectable signals of TR. Directly measured PA_S ranged from 21 to 95 mmHg (mean ± SD, 40 ± 18). Correlation between Doppler and catheter-measured PA_S was R-sq = 0.93 with a standard error of the estimate of 4.7 mmHg. Accurate results were obtained over a wide range of pulmonary pressures. Thus, noninvasive determination of PA_S is feasible in most patients including those with normal PA_S, and correlates extremely well with direct measurements.