Coarctation of the Aorta:
Coarctation of the aorta (coarctation = narrowing) is a congenital heart defect in which there is a narrowing where the ductus arteriosus is located. Coarctation of the aorta is considered when a segment of the aorta is narrowed to an abnormal width. The narrowing is most common where the aorta arches toward the abdomen and legs. When a patient has a coarctation, the left ventricle has to work harder and generate a much higher pressure than normal in order to force enough blood through the aorta to deliver blood to the lower part of the body. If the narrowing is severe enough, the left ventricle may not be strong enough to push blood through the coarctation, thus resulting in lack of blood supply and weak pulses in the lower extremities.
There are three type of aortic coarctations:
1) Preductal coarctation: In this case the narrowing is proximal to or before the ductus arteriosus. Blood flow to the aorta that is distal to the narrowing is dependent on the ductus arteriosus; therefore severe coarctation can be life-threatening.
2) Ductal coarctation: The narrowing occurs at the insertion of the ductus arteriosus. This kind usually appears when the ductus arteriosus closes.
3) Postductal coarctation: The narrowing is distal to or after the insertion of the ductus arteriosus. Even with an open ductus arteriosus, blood flow to the lower body can be impaired. This type is most common in adults. It is associated with notching of the ribs, hypertension in the upper extremities, and weak pulses in the lower extremities.