Accuracy of continuous wave Doppler predicted gradient in patients undergoing balloon pulmonary valvoplasty

14 patients who underwent balloon valvoplasty had trans-pulmonic gradient evaluated by continuous wave Doppler echocardiography. Maximum systolic gradients measured from Doppler flow velocities were correlated with peak to peak gradient obtained at cardiac catheterisation. Prior to valvoplasty, there was good correlation between the Doppler maximum gradient (92.85 +/- 34.7mm Hg) and the peak to peak catheter gradient (105.57 +/- 56.60 mm Hg), (r = 0.91, p = less than 0.001). Immediately after balloon valvoplasty, the maximum Doppler gradient did not correlate with the peak to peak catheter gradient (r = 0.33, p = NS). Exclusion of patients with infundibular gradients improved the correlation coefficient between the Doppler maximum and peak to peak catheter gradient to 0.69. At late restudy following valvoplasty, when regression of infundibular stenosis was noted in 6 out of 8 patients, the Doppler maximum and catheter peak to peak gradient had excellent correlation (r = 0.97, p = less than 0.001). In patients with lone valvular gradient immediately following valvoplasty and at late restudy, maximum Doppler gradients correlated well with catheter gradients in 14 estimations (r = 0.66, p = less than 0.01). This study shows that the non-invasive quantification of pulmonary valve stenosis can be reliably undertaken, using continuous wave Doppler echocardiography before balloon valvoplasty and during follow-up, after the procedure when the infundibular stenosis has regressed. The presence of an infundibular gradient immediately after balloon dilatation makes the Doppler prediction less reliable.