coarctation of the aorta
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Coarctation of the Aorta
A defect that develops in the fetus in which there is a narrowing of the aortic arch, the main blood artery that delivers blood from the left ventricle of the heart to the rest of the body. Coarctation of the aorta is diagnosed in both newborns and adults. Approximately 10% of newborns with congenital heart disease have coarctation of the aorta.
Blood leaves the heart by way of the left ventricle and is distributed to the body by arteries. The aortic arch is the first artery to carry blood as it leaves the heart. Other arteries to the head and arms branch off the aortic arch. A narrowing of the aorta at any spot produces resistance to the flow of blood. This causes high blood pressure before the narrowing and low pressure below the narrowing (downstream). Parts of the body supplied by arteries that branch off the aortic arch before the narrowing have high blood pressure, while most of the lower body does not receive enough blood supply. To compensate for this, the heart works harder, and the blood pressure rises.
Approximately half of all infants with coarctation of the aorta are diagnosed within the first two months of life. Frequently, there are other congenital cardiac complications present. Infants with Turner syndrome have a 45% rate of also having coarctation. There is evidence that some cases of coarctation may be inherited.
Causes and symptoms
In newborns with congenital heart disease, coarctation of the aorta develops while the baby is in the womb. Among the consequences of coarctation of the aorta is ventricular hypertrophy, an enlarging of the left ventricle in response to the increased back pressure of the blood and the demand for more blood by the body. Symptoms in infants include shortness of breath (dyspnea), difficulty in feeding, and poor weight gain. Older children usually don't have symptoms, but may display fatigue, shortness of breath, or a feeling of lameness in their legs.
Infants usually have an abnormal "gallop" heart rhythm and may also have heart murmurs. Sometimes excessive arterial pulses can be seen in the carotid and suprasternal notch arteries, indicating increased pressure in these arteries, while the femoral pulse is weak or cannot be detected. The systolic pressure is higher in the arms than in the legs. Enlargement of the heart can be seen in x rays. Similar symptoms are seen in older children and adults. A 10 mm Hg (mercury) pressure difference between the upper and lower extremities is diagnostic for coarctation of the aorta. For some patients, the systolic pressure difference is observed only during exercise. Infants frequently have an abnormal electrocardiogram (ECG) that indicates that the right or both ventricles are enlarged, while in older children the ECG may be normal or show that the left ventricle is enlarged. The coarctation may be detected in echocardiographic examination.
Drugs can be used to treat the hypertension and heart failure. Surgery is recommended for infants with other, associated cardiac defects and for those infants not responding to drug therapy. Surgery is indicated for infants that don't require immediate surgery, but who develop severe hypertension during the first several months of life. Patients are advised to avoid vigorous exercise prior to surgical correction of the coarctation. Recoarctation can occur in some patients, even if they have had surgery.
Approximately half of all infants diagnosed with coarctation of the aorta have no other cardiac defects and will respond well to medical management. Most of these children will eventually outgrow the condition after several years of life. Although their hypertension may increase for several months early in life, it will eventually decrease as the circulatory system develops. Surgery is required for infants that have severe coarctation of the aorta or have associated cardiac defects. The average life span of children who have coarctation of the aorta is 34 years of age. The most common complications for children who have not had surgery are hypertension, aortic rupture, intracranial bleeding, and congestive heart failure. Women who have an uncorrected coarctation of the aorta have a mortality rate of 10% during pregnancy and a 90% rate of complications.
Dyspnea — Difficulty in breathing. Usually associated with heart or lung diseases.
Electrocardiogram — A graph of the heart's beating produced by an instrument that detects the electrical signals made by the heart.
Alexander, R. W., R. C. Schlant, and V. Fuster, editors. The Heart. 9th ed. New York: McGraw-Hill, 1998.
coarctation of the aorta
A localized congenital malformation resulting in narrowing of the aorta, often resulting in hypertension in adolescents and young adults. On physical assessment, it produces a delayed pulse in the femoral arteries relative to the pulse perceived at the radial arteries. Chest x-rays may show rib notching. Surgical correction of the obstruction may cure high blood pressure.
See also: coarctation