The prestenotic and poststenotic dilatations result in a "figure 3" appearance of the aorta.

The aortic contour abnormalities that result in the "figure 3" sign are formed by prestenotic dilatation of the ascending aorta, indentation of the coarctation site, and poststenotic dilatation of the descending aorta

Coarctation of the aorta is associated with other congenital anomalies such as bicuspid aortic valve (70%), patent ductus arteriosus, ventricular septal defect, tricuspid atresia, and transposition of the great vessels. Noncardiac associations include berry aneurysms in the circle of Willis and Turner's syndrome. Diagnosing coarctation early is important to prevent associated complications including aortic aneurysm, dissection, and bacterial endocarditis at the coarctation site or bicuspid aortic valve.