Patients with congenital aortic stenosis, such as what you son had, are also at an increased risk for aortic root dilation. The two conditions often go together because they are linked to an abnormality in the proteins that make up valves and arterial walls. When the aortic root begins to dilate, it is extremely important to follow it very closely with imaging to assess its size. If greater than 5 - 6 cm one will need aortic root surgery. Allowing it to expand past 5 - 6 cm increases the risk of aortic root aneurysm rupture.