Figure 3: Bar graph of peak systolic pressure gradients (mmHg) across the coarctation of the aorta prior to (Pre) and immediately following (Post) balloon angioplasty in neonates (<30 days), infants (1 to 12 mo) and children (1 to 15 years). Note significant (P < 0.001) decrease in pressure gradient in each subgroup. Mean + standard error of mean (SEM) are shown. N indicated the number of patients in each subgroup.