Vascular Rings and Double Aortic Arch Explained

Vascular rings are very rare congenital heart defects occurring in less than one percent of the population. The main artery bringing blood to the body does not form correctly during fetal development, and rings of blood vessels develop that encircle and squeeze the trachea (windpipe), esophagus, or both. Surgery to repair the malformed blood vessels is the treatment for this condition, and children will generally recover fully after surgery without any long-term effects.

Vascular rings make up a small percentage of congenital heart defects, and double aortic arches account for just over 50% of them.

There are two types of vascular rings (VR):

• Incomplete VRs only partially surround the trachea and esophagus; some compress either the trachea or the esophagus, but most do not cause symptoms.
• Complete VRs fully surround the trachea and esophagus, and most cause symptoms.

The most common type of complete vascular ring is a double aortic arch (DAA). Instead of one aortic arch forming to the left of the trachea and esophagus, two arches form, one on each side of the two tubes and over both bronchi (the passages that connect your windpipe to your lungs).

How do the heart and aorta normally function?

The heart pumps oxygenated blood from your lungs into your body through a large artery coming off the top of the heart, called the aorta.

A healthy aorta comes off the left side of the heart at the top, curves to the left, the head and arm arteries branch off, and the aorta continues curving down to the lower body, forming an arch. This arch curves to the left of the trachea and esophagus.

The defect

Vascular rings can refer to any vascular encirclement of the trachea or esophagus by vessels that form incorrectly or differently from normal.

Parts of the malformed aorta will partially or completely surround the trachea or esophagus.

In a double aortic arch, the aorta forms into two arteries, one in front of the trachea and the esophagus and one behind them, forming a ring around the two tubes. The two blood vessels put pressure on the trachea and esophagus, constricting them.

Causes

Vascular rings are congenital heart defects, meaning they form while a baby develops before birth.

No definite cause is known for these malformations, but they are sometimes associated with chromosomal abnormalities.

They may form as a single heart defect or be associated with other heart defects, such as:

• Tetralogy of Fallot.
• Truncus arteriosus.
• Conotruncal anomalies.
• Ventricular septal defect.
• Transposition of the great arteries.

Symptoms

Vascular rings may compress the trachea or esophagus, leading to eating or breathing problems.

Often a vascular ring defect is mild enough that symptoms do not develop until the child is a few years old, and some never cause symptoms.

Pressure on the trachea can lead to:

• Coughing.
• Wheezing.
• Noisy breathing.
• Frequent respiratory infections.
• Stridor (high-pitched breathing noises).

Pressure on the esophagus leads to:

• Frequent vomiting.
• Choking during feeding.
• Difficulty eating and swallowing.

The child may also experience cardiac symptoms such as:

• Chest pain.
• A heart murmur.
• Cyanosis (bluish hue to the lips, nail beds, or skin).

An infant with a double aortic arch will develop symptoms earlier than with other forms of vascular rings. Symptoms usually start in early infancy and almost always before age three. Symptoms can be very severe and even life-threatening.

Diagnosis

If a double aortic arch is suspected based on symptoms and history, your child’s pediatrician will order tests to confirm the diagnosis. These tests could include:

• Chest x-ray.
• CT or MRI scans.
• Barium swallow study.
• Echocardiogram.
• Upper endoscopy.
• Bronchoscopy.

If a doctor suspects a heart defect before birth, a fetal echocardiogram (ultrasound of the heart before birth) can usually diagnose it.

Treatment

Surgery is the treatment for vascular rings.

The surgeon will make a cut between the ribs to access the heart and aorta. Then, the malformed blood vessels are cut and tied off to release the pressure on the trachea and esophagus.

In some cases, a less invasive procedure is appropriate.

Complications

Complications of untreated vascular rings can include:

• Failure to thrive.
• Tracheal erosion.
• Esophageal erosion.
• Frequent respiratory infections.
• Aortoesophageal fistula (a hole forms between the aorta and the esophagus).

Complications after surgery are uncommon. Most children recover fully after surgery without chronic problems. Those who develop problems tend to have respiratory issues.

Stridor is a frequent problem for a short time after surgery, as the trachea takes time to grow stronger. This stridor will usually clear up on its own, but additional surgery may be necessary to lift the aorta off the trachea.

Other complications that can arise include:

• Chylothorax, when lymph tissue builds up around the lungs.
• Transient hypertension, which is high blood pressure that only lasts for a little while.
• Vocal cord paralysis or paresis (muscle weakness).
• Aortoesophageal fistula (a hole between the aorta and the esophagus) may occur in rare cases and lead to large amounts of blood in the gastrointestinal tract.

Outlook

Surgery outcomes are generally excellent, with only 26 patients out of 300 needing further surgery after the initial repair.

Usually, children start to feel better and see a decrease in symptoms immediately after surgery. Some may continue to have trouble breathing due to the damage done to the trachea before the surgery.

If a severe vascular ring, especially a DAA, is left untreated, breathing difficulties could lead to premature death.

Children may need life-long follow-up care after surgery, but most will be able to live healthy, active lives.