Prediction of Pulmonary Artery Pressures by the Ratio of Pulmonary to Systemic Pressures Derived from Pulsed Doppler Echocardiography

We used a new method for the estimation of the ratio of pulmonary to systemic pressures by pulsed-wave Doppler echocardiography. Sixty-six patients undergoing cardiac catheterization, aged 7-62 years, were studied. These patients' right and left ventricular outflow velocity were examined by pulsed Doppler technique. Preejection period (PEP), ejection time (ET) and mean acceleration to peak velocity (ACCm) were measured on each wave form. The expression: F= (PEPxACCm) / ET for right and left ventricular outflows was calculated from the Doppler wave forms generated in each outflow which are the records of the ejection flow dynamics of each ventricle. The quotient of (F for the right outflow) / (F for the left outflow) was used to express the degree of pressure dependent variability between each subject's right and left ventricular outflow tracings. The ratio of the right to left ventricular outflow F indexes was almost identical to the ratio of systolic and mean pulmonary to systemic pressures (r=0.97±0.05; r=0.96±0.07). The product of the ratio of right and left ventricular outflow F indexes and arm systolic pressure gave an accurate estimate of systolic pulmonary pressure. It is concluded that this method can be successfully used for the noninvasive assessment of pulmonary pressures.