What is interrupted aortic arch?
Interrupted aortic arch is a very rare heart defect that occurs when the aorta does not develop normally while the baby is in the mother’s womb. It comprises about 1% of all congenital heart defects. It usually occurs along with other heart problems such as truncus arteriosus, ventricular septal defect, transposition of the great arteries, and aortic stenosis.
The aorta is the large blood vessel that arises from the left side of the normal heart and takes red blood out to the body. The first part of the aorta, called the ascending aorta (1) arises upwards. It then curves leftward forming the aortic arch (2). The aorta then curves downward towards the lower body, and this part is called the descending aorta (3). Three blood vessels exit from the aortic arch and supply the head and arms with red blood. These vessels are called the innominate artery (4), the left carotid artery (5), and the left subclavian artery (6).
In babies with interrupted aortic arch, there is a complete blockage between the ascending and the descending aorta (1). This means that there is no direct way for red blood leaving the heart to reach the body parts that are "downstream" from the blockage. The site of the defect varies (2) and may or may not involve the take-off of the head and neck vessels. In most babies with interrupted aortic arch (70-90%) there is also a large ventricular septal defect (3).
In newborns with interrupted aortic arch, the only way for blood to bypass the blockage is via the patent ductus arteriosus (4). Prior to birth, this small blood vessel permits blood to by-pass the baby’s fluid-filled lungs. One or two days after birth, this vessel usually closes on its own. In a baby with interrupted aortic arch, if the duct closes, blood can no longer reach the lower body. This can cause the baby to suddenly become very ill. Therefore, after the diagnosis is made, a medicine called prostaglandin is used to keep the ductus arteriosus open until surgery.
Interrupted aortic arch is more common in children with DiGeorge syndrome. DiGeorge syndrome occurs when part of chromosome 22 is lost during the earliest stages of fetal life. In addition to heart problems, children with DiGeorge syndrome may have decreased ability to resist viral infections, low blood calcium, cleft palate, kidney problems, changes in facial features, and learning problems.
What are the effects of this defect on my child's health?
Interrupted aortic arch is a serious defect that requires surgery as soon as possible. The problem is often discovered 3 or 4 days after birth when the patent ductus closes. When this happens, symptoms of shock can develop very quickly. Symptoms of congestive heart failure such as rapid breathing, clammy sweating, and poor feeding may also occur.
How is this defect diagnosed?
Prenatal diagnosis: Interrupted aortic arch can be diagnosed before birth by a fetal echocardiogram or heart ultrasound as early as 18 weeks into the pregnancy. This test is done when there is a family history of congenital heart disease or when a question is raised during a routine prenatal ultrasound.
Symptoms: Most babies do well right after birth but develop symptoms within the first days of life. Symptoms of congestive heart failure such as rapid breathing, clammy sweating, and poor feeding often develop during the first week of life.
Physical findings: Most babies with interrupted aortic arch are born at term and are a normal weight and length. A heart murmur is usually heard. The heart rate and breathing rate may be increased and the liver may be enlarged. The left arm and/or leg pulses may be absent.
Medical tests: The suspected diagnosis is confirmed by an echocardiogram. Sometimes, a heart catheterization is needed to help the doctors plan the surgery. An oxygen saturation test is used to measure the blood oxygen levels. Other tests include an electrocardiogram and chest x-ray.
How is the problem treated?
Interrupted aortic arch is a serious heart defect that requires surgery soon after birth. The goal of surgery is to create remove the blockage. This used to be done in a two-stage operation but is now done most of the time in one stage. The two ends of the aorta are sewn together (1) and the patent ductus arterious (2) is tied off. Sometimes a patch is needed to reinforce the repair. If present, a patch is sewn over the VSD (3).
What are the long-term health issues for children with interrupted aortic arch?
In recent years, the outcomes for children with interrupted aortic arch have greatly improved with 85 to 90% hospital survival.
Over time, a narrowing can develop at the site of repair that may be treated with balloon angioplasty. In some patients, subaortic stenosis can occur needing re-operation.
SBE: Children with interrupted aortic arch are at increased risk for subacute bacterial endocarditis (SBE). This is an infection of the heart caused by bacteria in the blood stream. Children with heart defects are more prone to this problem because of the altered flow of blood through the heart and or abnormalities of the valves. It can occur after dental work or medical procedures on the GI or respiratory tract because these procedures almost always result in some bacteria entering the blood. SBE can usually be prevented by taking an antibiotic before these procedures.
Exercise guidelines: An individual exercise program is best planned with the doctor so that all factors can be included. Children with interrupted aortic arch are usually restricted from vigorous or competitive sports but can participate in recreational sports. It is important for them to always be able to self-limit their activity, that is, to rest whenever they feel the need to do so. The children can usually participate in gym class but should be allowed to self-limit their level of exertion and they should not be graded (which could increase the pressure to exceed their natural limits).
References
Haas F, Goldberg C, Ohye R, Mosca R, Bove E. Primary repair of aortic arch obstruction with ventricular septal defect in preterm and low birth weight infants. Eur J Cardiothor Surg 2000;17:643-647.
Jonas R. Interrupted aortic arch. In Pediatric Cardiac Surgery, Mavroudis C & Backer CL, eds. St. Louis MO: Mosby 1994: 183-192.
Morris J & McNamara D. Coarctation of the aorta and interrupted aortic arch. In Garwson A, Bricker J, Fisehr D Y Neish S, ed. The Science and Practice of Pediatric Cardiology, 2nd Ed. Baltimore, MD: Williams & Wilkins, 1998, Vol 1:1339-1346.
Sandhu S, Beekman R, Mosca R, Bove E. Single-stage repair of aortic arch obstruction and associated intracardiac defects in the neonate. Amer J Cardiol 1995; 75: 370-373.
Written by: S. LeRoy RN, MSN, CPNP
Reviewed September, 2012