Pediatric Heart Disease Coarctation Aorta

Coarctation of the aorta (COA) is a congenital defect of the aorta, the main artery running from the heart to the rest of the body. When someone suffers from COA, his aorta is too narrow and, therefore, sends too much blood to the upper body and too little to the lower body.

Coarctation of the aorta results in serious blood pressure imbalances and, if left untreated, congestive heart failure. Often associated with aortic valve defects, coarctation of the aorta is believed to be responsible for up to 8 percent of congenital heart defects.

Coarctation of the Aorta Causes

While the medical community knows that birth defects cause coarctation of the aorta, the exact reasons that these birth defects occur remains a mystery. One theory suggests COA may be related to the ductus arteriosus, a special blood vessel found in unborn children.

Specialized blood vessel tissue in the ductus arteriosus close off this blood vessel shortly after birth. Coarctation of the aorta may result from the presence of ductus arteriosus tissue that causes the aorta to narrow in an attempt to close up entirely.

COA Risk Factors

While the cause of coarctation of the aorta is unknown, the following factors increase the risk that newborns and infants will suffer from coarctation of the aorta:

  • chromosomal defects, such as Turner’s syndrome or Down’s syndrome
  • certain heart defects, such as bicuspid aortic valve and ventricular septal defect
  • gender (Males are twice as likely as females to suffer from coarctation of the aorta.).

Coarctation of the Aorta Symptoms

Coarctation of the aorta is often asymptomatic, meaning that it is a condition that tends to exist independent of any symptoms. As a result, many cases of COA aren’t diagnosed until late childhood or adulthood. A person with coarctation of the aorta may have a low tolerance for physical activity. Similarly, he may experience chest pain, leg pain, headaches and heart palpitations during or after physical exercise.

In cases where coarctation of the aorta is marked by symptoms, possible symptoms may include:

  • chest pain
  • cold hands or feet
  • dizziness
  • fainting
  • fatigue
  • headaches
  • leg cramps after exercising
  • nosebleeds
  • shortness of breath.

About 50 percent of infants born with coarctation of the aorta display symptoms within a few days of birth. When COA symptoms do develop in newborns, the case is usually severe.

Diagnosing Coarctation of the Aorta

Early diagnosis of COA in a newborn typically occurs in the most serious cases because the infant may have heart murmurs (unusual sounds due to irregular heartbeats) or exhibits a weak or elusive pulse in the groin area.

If symptoms are not apparent, the aortic defect may go unnoticed for years. In older children and adults, the first indication of coarctation of the aorta is usually abnormal blood pressure readings during routine physicals.

People with coarctation of the aorta have significantly different blood pressure readings for their upper and lower body regions. While coarctation of the aorta causes high blood pressure in the arms, neck and head, it causes very low blood pressure in the groin and legs. Due to heart strain caused by COA, heart murmurs may also be detectable.

Once coarctation of the aorta is suspected, the condition can be confirmed with an echocardiology test. Echocardiology uses sound waves to construct an image of the heart and aorta.

While an echocardiogram is the preferred tool for making a coarctation of the aorta diagnosis, the test does not work well for older children. Diagnostic alternatives to echocardiology include:

  • cardiac catheterization
  • CT scans
  • Magnetic Resonance Imagery (MRI).

COA Complications

Left untreated, coarctation of the aorta can have severe consequences. Conditions arising from untreated COA include:

  • aortic aneurysm
  • aortic dissection
  • aortic rupture
  • coronary heart disease
  • endocarditis
  • heart failure
  • hypertension
  • intracerebral hemorrhage
  • stroke.

Endocarditis, or infection of the heart, is a risk for anyone with untreated coarctation of the aorta. As a result, doctors prescribe COA patients antibiotics to take before and after dental work and surgery to lower the risk of infection. Proper dental hygiene can also reduce the risk of endocarditis.

Coarctation of the Aorta Treatments

As symptoms of coarctation of the aorta are often severe in newborns, the first stage of treatment is to stabilize blood flow, increasing blood flow to the lower body. To accomplish this, newborns with COA receive intravenous prostaglandin. Prostaglandin prevents ductus arteriosus closure, creating a temporary alternate path for blood to flow to the lower body.

In addition to taking medication to strengthen heart contractions, infants with coarctation of the aorta are also generally placed on ventilators to ensure sufficient oxygen reaches the blood. Surgery is scheduled as soon as patients’ blood pressure stabilizes.

Surgery for Infants with Coarctation of the Aorta

A few surgical options exist for treatment of coarctation of the aorta in infants. The most common COA treatment is simply to remove the narrowing, or coarctation, and then to reconnect the two pieces of aorta together. This procedure is known as a surgical re-section.

Surgeons can also widen the coarctation using a patch or portion of artery tissue. However, this type of procedure is less common than re-sectioning.

Balloon Dilation and COA

Older children and adults with coarctation of the aorta are also likely to undergo a surgical resection of the aorta. In certain cases, however, balloon dilation may be used to correct the aortic narrowing.

Balloon dilation uses a catheter to deliver a small balloon through the arteries to the aortic coarctation. Once in position, the balloon is inflated, expanding the narrowed aorta. The balloon is then removed. If deemed necessary, a mesh coil or tube is inserted into the aorta to keep the widened artery from collapsing.

Balloon dilation is not commonly used to correct coarctation of the aorta in infants. If balloon dilation is performed on very young patients, coarctation of the aorta may recur as the child grows.

Prognosis for COA

Treatment outcomes for coarctation of the aorta are generally very positive. However, the prognosis depends on how old the patient is. For example, if balloon dilation or surgical resection of the aorta are performed in infancy, coarctation will likely recur as the child grows.

After surgical correction of COA, regular blood pressure tests are needed, as people with corrected coarctation of the aorta remain at high risk for hypertension and aortic valve disorders.

Resources

American Heart Association (n.d.). Coarctation of the aorta. Retrieved September 14, 2007, from the AHA Web site: www.americanheart.org/presenter.jhtml?identifier=11069.

Cincinnati Children’s Hospital Medical Center (n.d.). Coarctation of the aorta. Retrieved September 14, 2007, from the Cincinnati Children’s Hospital Medical Center Web site: www.cincinnatichildrens.org/health/heart-encyclopedia/anomalies/coarctation.htm.

U.S. National Library of Medicine (2004). Coarctation of the aorta. Retrieved September 14, 2007, from the NLM Web site: www.nlm.nih.gov/medlineplus/ency/article/000191.htm.