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.

Types of Coarctation of the aorta:

There are three type of aortic coarctations:

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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.

Signs and symptoms:

Symptoms depend on how much blood can flow through the artery. Other heart defects may also play a role.

About half of newborns with this problem will have symptoms in the first few days of life. These can include breathing fast, problems eating, increased irritability, and increased sleepiness or becoming poorly responsive.

In milder cases, symptoms may not develop until the child has reached adolescence. Symptoms include:

• Chest pain
• Cold feet or legs
• Dizziness or fainting
• Decreased ability to exercise
• Failure to thrive
• Leg cramps with exercise
• Nosebleed
• Poor growth
• Pounding headache
• Shortness of breath

Note: There may be no symptoms.

Diagnosis:

Chest radiography:

• Radiography in patients with early onset of coarctation of the aorta may reveal cardiomegaly, pulmonary edema, and other signs of congestive heart failure (CHF).
• Radiography in patients with late onset of coarctation of the aorta may reveal cardiomegaly. An inverted “3” sign of the barium-filled esophagus or a “3” sign on a highly penetrated chest radiograph (frontal view) may be visualized. Rib notching secondary to collateral vessels may also be seen.

Echocardiography:

• Echocardiography delineates intracardiac anatomy and allows assessment of associated significant intracardiac anomalies. The suprasternal notch 2-dimensional echocardiographic view allows evaluation of the aortic arch to assess the transverse aortic arch, isthmus, and severity of coarctation. Doppler echocardiography is used to measure the gradient at the site of coarctation and to identify the pattern of diastolic runoff typically seen in patients with severe obstruction.

Electrocardiography:

• ECG in the neonate or infant with early onset of coarctation of the aorta may reveal right ventricular rather than left ventricular (LV) hypertrophy. The reasons for right ventricular preponderance in the face of LV outlet obstruction are mentioned in Pathophysiology.
• ECG findings in patients with late onset of coarctation of the aorta may be normal or may reveal LV hypertrophy and may show signs of LV ischemia or strain. Sometimes, LV hypertrophy may manifest as increased S waves in leads V5 and V6, the so-called posterobasal LV hypertrophy.

Magnetic resonance imaging (MRI):

• An MRI scan is a test that uses a magnetic field and pulses of radio wave energy to make pictures of your body. An MRI of your chest will reveal the location of the coarctation of the aorta and determine whether it affects other blood vessels in your body.

Computerized tomography (CT) angiogram:

• A CT angiogram allows your doctor to check your arteries to see if your aorta is narrowed. In this minimally invasive test, you’ll change into a hospital gown and lie on a table that’s part of the CT scanning machine. You’ll receive an injection of a radioactive dye, and the doughnut-shaped CT scanner will be moved to take images of the arteries in your heart. The images are then sent to a computer screen for your doctor to view.

Cardiac catheterization:

• During this procedure, your doctor inserts a thin flexible tube (catheter) into an artery or vein in your groin and threads it up to your heart. A dye is injected through the catheter to make your heart structures visible on X-ray pictures. Cardiac catheterization helps determine the severity of the aortic coarctation.

Treatment:

Treatment options for coarctation of the aorta depend on the patients age when they’re diagnosed and how narrowed your aorta is. Other heart defects may be repaired at the same time as aortic coarctation. Treatment approaches usually consist of surgery or a procedure called balloon angioplasty.

Surgery:

There are several open-heart surgical techniques to repair aortic coarctation.  The options include:

• Resection with end-to-end anastomosis. This method involves removing the narrowed segment of the aorta (resection) followed by connecting the two ends of the aorta together (anastomosis).
• Patch aortoplasty. The doctor may treat the coarctation by cutting across the constricted area of the aorta and then attaching a patch of synthetic material to widen the blood vessel. Patch aortoplasty is useful if the coarctation involves a long segment of the aorta.
• Left subclavian flap angioplasty. A portion of the left subclavian artery, the blood vessel that delivers blood to the left arm, may be used to expand the narrowed area of the artery.
• Bypass graft repair. This technique involves bypassing the narrowed area by inserting a plastic tube called a graft between the portions of the aorta.

Balloon angioplasty and stenting:

• Balloon angioplasty is an option for initially treating aortic coarctation or for treating re-narrowing (re-coarctation) that has occurred after surgery. During this procedure, the doctor inserts a thin flexible tube (catheter) into an artery in the groin and threads it up through the blood vessels to the heart. An uninflated balloon is placed through the opening of the narrowed aorta. When the balloon is inflated, the aorta widens and blood flows more easily. In some cases, a mesh-covered hollow tube called a stent is inserted to keep the narrowed part of the aorta open.

Medication:

• Medication isn’t used to repair coarctation of the aorta, but it may be used to control blood pressure before surgery. Although repairing aortic coarctation improves blood pressure, many people will still need to take medication, even after a successful surgery.
• Babies with severe coarctation of the aorta may receive a drug called prostaglandin E. This drug helps keep the ductus arteriosus open, providing a bypass for blood flow around the constriction, until the coarctation is repaired.

After treatment:

• The most common long-term complication of coarctation of the aorta is high blood pressure. Although the blood pressure usually falls after the aortic coarctation has been repaired, it may still remain higher than normal. Occasionally, the segment of the aorta that has been repaired will become weak and bulge (aortic aneurysm) and may eventually rupture. In some cases, the coarctation will recur, possibly even years after treatment, but it’s possible to have additional surgeries or procedures to correct the re-narrowing.

• http://www.cincinnatichildrens.org/health/c/coarctation/
• http://www.nlm.nih.gov/medlineplus/ency/article/000191.htm
• http://en.wikipedia.org/wiki/Coarctation_of_the_aorta
• http://emedicine.medscape.com/article/895502-workup#a0720
• http://emedicine.medscape.com/article/895502-workup#a0721
• http://www.mayoclinic.org/diseases-conditions/coarctation-of-the-aorta/basics/tests-diagnosis/con-20031772