Changes in band parameters over time (tables 2 and 3)
In patients who required an atrial intervention there was a significant increase in systolic velocity (figure 4a) with time and a significant decrease in diastolic velocity prior to septostomy, with a rise post-septostomy (figure 4b). with time The S vel: D vel and PI also showed a significant change over time, with an increase prior to septostomy and then a fall after the septostomy (figure 4b and 4c). There were no significant differences in the pattern of change of parameters over time between the two bands but the response of the left compared to the right pulmonary artery band Dopplers in respect to diastolic velocity, S vel: D vel ratio and PI was more significant (figure 4a-d).
Prior to septostomy compared to controls (table 4), the LPA S vel was significantly lower (2.5m/s vs 3.5m/s, P <0.05) as was the LPA D vel (1.1m/s vs 1.6m/s, p <0.05) with a significantly lower mean (1.8m/s vs 2.6m/s, P <0.05) and VTI (144.5cm vs 196.7cm, p <0.05). The LPA S vel: D vel ratio and PI were also significantly higher (2.8 vs 2.0 and 1.0 vs 0.7 respectively, p <0.05). There were no significant differences in septal mean velocity or VTI or RPA parameters.
The shape of the RPA and LPA Doppler was predominantly “saw-tooth” in most patients (97%).  It was noted that in the LPA this pattern changed to a more pulsatile pattern (reflecting a lower diastolic) in several of the patients who required an atrial intervention. Even on the immediate post-intervention scan in some patients, there was an improvement in the shape back to “sawtooth” (figure 1).