Pulsed Doppler echocardiographic assessment of extraparenchymal pulmonary vein flow

Extraparenchymal pulmonary vein flow profiles were assessed by pulsed Doppler echocardiography in three groups of patients. Group I comprised 41 normal patients. Group II comprised 16 patients, 10 of whom had nonpulsatile pulmonary artery flow (5 with a right atrium to pulmonary artery Fontan procedure and 5 with a Glenn shunt). Six patients with pulsatile pulmonary artery flow had simultaneous Doppler and left atrial pressure measurements during cardiac catheterization. Group III comprised one patient with pulmonary vein obstruction, six with a large left to right shunt at ventricular level and two with pulmonary vascular disease. In Group I, biphasic forward pulmonary vein flow occurring during ventricular systole and diastole was observed in 26 subjects, 15 others had triphasic flow. In those with triphasic flow, the ventricular systolic component was divided into early and late. Reversed flow in the pulmonary veins during atrial systole was seen in 36 of the 41 subjects. The flow pattern in Group II was identical irrespective of the presence of pulsatile or nonpulsatile flow. The two periods of ventricular systolic flow occurred during the a to c and c to x descent, with the ventricular diastolic flow occurring during the y descent. Variations in waveform were mirrored in the left atrial pressure. Neither increased nor decreased pulmonary artery flow substantially altered the pattern. Pulmonary vein obstruction produced a distinctive pattern of high velocity turbulent flow. This technique demonstrates that extraparenchymal pulmonary vein flow is dependent on left atrial pressure events. It has major potential applications in patients who are prone to develop pulmonary vein obstruction.