Estimation of pulmonary artery pressure from pulmonary vein wedge pressure

Correlations between pulmonary artery and pulmonary vein wedge pressures were investigated in 13 patients with atrial septal defect and 1 patient with Tetralogy of Fallot. Pulmonary vein wedge pressure wave form resembled that of pulmonary artery pressure, and the former lagged behind the latter by 70 to 110 msec (mean 88 +/- 14) as observed by the fluid-filled catheter system. Diastolic pulmonary artery and diastolic pulmonary vein wedge pressures were nearly identical. Although systolic and mean pulmonary artery pressures correlated well with respective pulmonary vein wedge pressures, there were discrepancies when systolic and mean pulmonary artery pressure exceeded 35 and 20 mm Hg, respectively. However, systolic and mean pulmonary artery pressures could be estimated by adding the difference between the diastolic pulmonary vein wedge pressure and the mean left atrial pressure to corresponding systolic or mean pulmonary artery pressure. In conclusion, pulmonary artery pressures can be estimated by measuring pulmonary vein wedge pressures and the mean left atrial pressure.