Statistical Considerations. The treatment groups will be frequency-matched for documented confounders. The confounding variables will include: (a) Age at treatment; (b) Current age; (c) Bicuspid aortic valve as it is associated with impaired aortic elasticity. Because of the relatively large number of matching variables and three treatment groups, matching individual subjects was not feasible. During analysis, the treatment groups will be compared for each of these confounding variables and appropriate adjustments made, if needed. Differences in the confounding variables across the three treatment groups will be evaluated using Fisher's exact test for severity of coarctation and the Kruskal-Wallis test for age at treatment, current age and bicuspid aortic valve. The primary outcome variable will be carotid-femoral PWV assessed by tonometry. Differences in cfPVW across groups will be explored using one-way analysis of variance. If differences in matching variables are detected among the groups, adjustment will be made using analysis of covariance. Post-hoc analyses will be performed as necessary.