Usefulness of the Pulmonary Arterial Systolic Pressure to Predict Pulmonary Arterial Wedge Pressure in Patients With Normal Left Ventricular Systolic Function

Abstract

Tissue Doppler imaging combined with transmitral Doppler permits estimation of pulmonary artery wedge pressure (PAWP) in many, but not all, patients, whereas pulmonary artery systolic pressure (PASP) and cardiac output (time-velocity integral method) are routinely measured. It was hypothesized that simple Doppler echocardiographic measurements could be used to estimate PAWP in many patients by rearranging the equation for pulmonary vascular resistance ([mean pulmonary artery pressure - (left atrial pressure/cardiac output)] x 80). Data from 69 patients (mean age 59 +/- 15 years) were reviewed, including cardiac output, transmitral mitral E wave velocity, and lateral tissue Doppler imaging mitral annular early diastolic velocity. PAWP was determined in the 2 ways of (1) measured (PAWPm) using the regression equation PAWPm = 1.91 + (1.24 * transmitral mitral E wave velocity/mitral annular early diastolic velocity) developed and validated by Nagueh, and (2) using a nomogram that we developed to predict PAWP when cardiac output and PASP were known. Moderately strong correlation was found between PASP and PAWPm (r = 0.73), and this correlation improved when excluding patients with pulmonary or liver disease and restricting cardiac output to 3.5 to 6.0 L/min (physiologic range; r = 0.81). Furthermore, the relation between PAWPm and PASP allowed for discrimination of high versus low PAWP: 36 of 37 patients with PASP < or =30 mm Hg had PAWPm < or =15 mm Hg (sensitivity 97%, specificity 47%). Conversely, 9 of 9 patients with PASP > or =40 mm Hg had PAWPm > or =12 mm Hg (sensitivity 100%, specificity 70%). Predicted PAWP correlated well with PAWPm (r = 0.63) and improved when patients with liver or pulmonary disease were excluded (r = 0.83). In conclusion, PASP strongly correlated with PAWP, and this principle can be exploited to rapidly detect patients with low or high PAWP.