Echocardiographic method for the estimation of pulmonary artery pressure in chronic lung disease.

The prognostic implications of pulmonary hypertension in chronic lung disease, and the difficulty in establishing its severity without cardiac catheterisation, indicate the need for a reliable non-invasive method of assessing the pulmonary artery pressure. It is likely that the time taken by the right ventricle to generate a sufficiently high pressure to open the pulmonary valve will increase progressively as the pulmonary arterial diastolic pressure rises. Therefore, the time interval between closure of the tricuspid valve and opening of the pulmonary valve has been obtained by high-speed echocardiographic recordings of the tricuspid and pulmonary valves in a group of 17 patients with chronic lung disease. Each patient underwent right heart catheterisation immediately after the echocardiographic examination so that the pulmonary arterial diastolic pressure could be obtained directly. A range for the group from 15 mmHg (2.0 kPa) to 45 mmHg (6.0 kPa) was observed. The linear correlation between the measured diastolic pressure and time interval from the tricuspid valve closure to pulmonary valve opening was highly significant (r = 0.94, p = less than 0.001) and the scatter was relatively small. It is therefore suggested that this time interval, obtained non-invasively by echocardiography, can be used as an index of the severity of pulmonary hypertension associated with chronic lung disease.