There are no prior trials of preventing or treating aortic injury associated with CoA and thus no basis for comparison. A single outcome assessment will not suffice since patients can receive a device for either indication. A 3-category Severity of Illness Scale (SIS) was developed based on clinical judgment of a panel of pediatric cardiologists and reviewed by a Data \& Safety Monitoring Board (DSMB) and the FDA Office of Device Evaluation. Five levels of severity have been defined for each of the 3 illness categories, including: Upper extremity hypertension, Upper to lower extremity pressure difference, and Severity of aortic wall injury. The DSMB will assign a level of illness from the SIS for each patient at baseline and one year follow up. Improvement by at least one level will indicate clinical importance. Safety is evaluated by identifying adverse events and comparing their occurrence to surgical repair of CoA in similar age groups reported in the medical literature.
