[Diagnosis of pulmonary hypertension using pulsed Doppler cardiography]

The accuracy of pulsed Doppler cardiography in predicting pulmonary hypertension was assessed in 70 patients (aged 16-72 years) with varying cardiac disease, who had undergone catheterization. Doppler velocity traces were recorded from four sampling sites in the pulmonary outflow tract and from the tricuspid valve. These results were compared to the invasive data. An inverse correlation (r = -0.77) was found between acceleration time (onset of RV ejection to peak pulmonary velocity) and mean pulmonary arterial pressure, with the sampling site in the centre of the pulmonary valves or of the RV outflow tract (r = -0.71). Acceleration time was inversely related to patient age but was not dependent on heart rate or on cardiac output. The sensitivity of the acceleration time was 85-91% for the diagnosis of moderate or severe pulmonary hypertension, and the predictive value was greater than 90%. The following measurements were less helpful in diagnosing pulmonary hypertension: peak velocity of pulmonary arterial blood flow, its mean acceleration, RV isovolumic relaxation time and the qualitative sign of a presystolic pulmonary flow wave induced by atrial contraction. A reversal of systolic flow at the level of the pulmonic valves, measured as time of forward flow in percent of RV ejection time, was found only in patients with moderate or severe pulmonary hypertension. This was a sensitive marker of an elevated pulmonary arterial resistance (greater than or equal to 95%), the mechanism of which is not yet fully understood.