The severity of pulmonary valve or artery obstruction in children estimated by Doppler ultrasound.

Doppler echocardiographic estimation of pressure gradient has been compared to that measured at cardiac catheterisation in 37 children, 6 weeks to 15 years of age, with suspected pulmonary valve stenosis or a pulmonary artery band. Various parasternal and subcostal positions were explored to obtain the maximum velocity of blood flow and the valve gradient was calculated from the modified Bernoulli formula. The Doppler study was performed at the time of catheterisation in 19, the maximum velocity being measured during catheter withdrawal in 7, immediately after withdrawal in 7, and while simultaneous right ventricular and pulmonary arterial pressures were measured in 5. Five other patients were studied within 24 hours of catheterisation and the other 13 within 6 months. Comparison of Doppler and catheterisation gradients showed a close correlation, this being particularly good where simultaneous right ventricular and pulmonary arterial pressures were measured. Doppler now provides an accurate non-invasive measurement of the severity of pulmonary valve stenosis and the adequacy of a pulmonary artery band.