What is a Vascular Ring?
"Vascular rings" refer to a variety of similar malformations in the chest involving the heart’s major blood vessels. The problem resulting from vascular rings is compression of the body’s windpipe (trachea) and/or food tube (esophagus). There are many varieties of vascular rings – the double aortic arch is one of them.
The main blood vessel that carries blood from the heart to the rest of the body is called the aorta. Normally shaped like a candy cane, the aorta leaves the heart’s lower left side and heads up toward the head, and then makes an arch – a 180-degree curve – in the upper chest to the left of the windpipe. The aorta then goes down the chest and into the abdomen.
Along with the rest of the heart, the aorta and its arch develop during the first eight weeks in the womb. During that developmental phase of the fetus, six sets of arching arteries form above the heart. By the end of the second month of fetal development, some parts of these arches merge or disappear, leaving behind the aorta that arches on the left side of the windpipe and its branches and the pulmonary arteries that supply to the lungs. The ductus arteriosus is another vessel that is formed from parts of these embryonic arches.
When arches and vessels that either should have become arteries or should have disappeared are still present at birth, they can form a vascular ring. This is an extra arch of blood vessels that partially or fully encircles and constricts the windpipe (which carries air to the lungs) and/or the esophagus (which carries food to the stomach).
The condition is rare, at just one percent of all congenital heart defects.
The two most common vascular ring types are:
- Double aortic arch: Two aortic arches form, one on the left side of the heart and one on the right. Usually the right arch dominates, while the other is underdeveloped. Both aortic arches encircle the trachea and esophagus.
- Right aortic arch with aberrant left subclavian artery and left ligamentum: This refers to an arch of the aorta that curves to the right from the heart – not to the left as in normal aortic arches. (Aberrant refers to it being out of place.) An abnormal branch from the descending aorta goes behind the esophagus. The subclavian artery refers to an artery that goes toward the left arm. The ligamentum is a remnant of a blood vessel that exists in the fetus but disappears in newborns. Its purpose is to connect the aorta and pulmonary artery until the baby can breathe outside the womb. The ligamentum connects between pulmonary artery and left subclavian artery and completes the ring around the trachea and esophagus.
What are the causes?
The causes of heart defects such as vascular rings among most babies are unknown. Some babies have heart defects because of changes in their genes or chromosomes. A combination of environmental exposures during fetal development and genetic factors are likely responsible, but little is known about the specific cause.
How is it diagnosed?
Diagnosis of vascular rings is difficult during pregnancy because some of the conditions that cause vascular rings (e.g., ligametum) is a normal and essential structure for the fetus before birth. Some vascular rings such as double aortic arch may be diagnosed during pregnancy with a fetal echocardiogram, which is a specialized ultrasound of the fetal heart. The affiliated physicians in the Fetal Cardiology Program at The Fetal Center will confirm a diagnosis and prepare a delivery plan for both mom and baby. A multidisciplinary team of specialists will also develop the baby's immediate care plan following delivery.
If vascular rings is not diagnosed in utero, and suspicion of a heart defect occurs after the baby is born, a pediatrician will refer the patient to a pediatric cardiologist, pulmonologist or gastroenterologist to determine the diagnosis.
A vascular ring can create breathing and digestive issues, often starting in a baby’s first few months or year of life. The more the ring constricts, the worse the symptoms will be and the earlier in life they will appear. Loud or labored breathing, a high-pitched cough and wheezing – especially when the baby is feeding – all suggest breathing problems. The child also may choke, vomit or have difficulty swallowing or feeding, which may lead to poor growth. Gastroesophageal reflux (GERD, or acid reflux), in which stomach contents back up into the esophagus, also may co-exist. Babies and children may have repeated respiratory infections or pneumonia.
Sometimes symptoms are mild, and the vascular ring is not discovered until the child is being evaluated for another health issue. In such cases, the patient’s family and doctor may choose to monitor the child rather than treat the vascular ring. The child’s pediatrician will listen to his or her breathing to rule out asthma and will listen to his or her heart via a stethoscope to check for heart issues.
If the doctor suspects the child has a vascular ring, the following tests may be ordered:
- Chest X-rays, a painless exam that creates images of the heart and lungs, making major flaws visible.
- A cardiac echocardiogram (echo), using sound waves (ultrasound) to produce images of the heart and blood vessels’ structures on a screen. This painless exam reveals whether the heart is pumping properly.
- A computed tomography (CT) scan of the heart and major blood vessels in the chest. This is a more detailed form of X-ray using opaque dye injected in blood vessels, revealing anatomic oddities.
- A bronchoscopy, in which a thin tube with a camera is wound through the mouth into the throat to examine the airways of the lungs.
- A cardiac MRI (magnetic resonance imaging), a painless exam using radio waves, magnets and a computer to form three-dimensional images of the heart, which can reveal structural abnormalities.
- Angiography, an X-ray of the blood vessels, often using a thin tube that winds from the groin to the area of concern, and the intravenous injection of contrast dye to reveal structural flaws.
- An esophagram or barium swallow, an X-ray of the esophagus using a special dye to highlight the structure.
How is it treated?
The only treatment for vascular rings is surgery. Surgery is performed through a small incision on one side of the chest between the ribs or sometimes through an incision in the front via breastbone. The vascular ring will be disrupted by removing the unneeded arch (if the child has a double aortic arch) or dividing the ligamentum (if the child has right aortic arch with left ligamentum arteriosum). These surgeries are generally performed when the diagnosis is made, regardless of age. The technique may vary, depending upon age and patient size.
With either surgical approach, this dividing of the blood vessel, or “opening” of the vascular ring, relieves the compression on the trachea and esophagus. The esophagus is rarely permanently damaged from growing and developing with compression. In some older children, the trachea may remain narrowed despite having the vascular ring opened. The severity of tracheal narrowing varies from patient to patient, and should be discussed with physicians.
What are the long-term effects?
Surgery relieves most symptoms, though sometimes major breathing issues take months to disappear, as the windpipe expands to its natural shape, after having been confined by the vascular ring. When active, children may breathe loudly until vascular ring is resolved. Children should have regular checkups with their pediatric cardiologist.
Why choose the Children’s Heart Program?
As part of the Children’s Heart Program at Children’s Memorial Hermann Hospital, the affiliated cardiologists and affiliated cardiovascular surgeons collaborate as a multidisciplinary team to treat babies prior to birth, infants, children and young adults with congenital and acquired heart disorders. The team of affiliated physicians, nurses and coordinators work together with you to determine the best treatment plan for your child. Your child’s referring physician is also kept fully informed of your child’s treatment plan.
At Children’s Memorial Hermann Hospital, the affiliated cardiologists and affiliated cardiovascular surgeons understand the unique challenges, circumstances and intricacies of caring for young patients with heart conditions. In addition to the team’s medical expertise, Children’s Memorial Hermann Hospital provides families with patient-centered care, keeping families fully involved as part of the child’s treatment team as well as offering resources to meet the needs of your entire family.
Pediatric Cardiology Clinic
The University of Texas Health Science Center Professional Building
6410 Fannin, Suite 370
Houston, TX 77030
Phone: (832) 325-6516
Pediatric Cardiovascular Surgery Clinic
The University of Texas Health Science Center Professional Building
6410 Fannin, Suite 950
Houston, TX 77030
Clinic Phone: (832) 325-7234
Nurse Line: (713) 500-7324
Note: This page is meant to be a helpful, informative introduction on the subject of vascular rings in children. The information may not be applicable to all cases, especially if there are additional defects. It is not meant to replace the opinion of a personal physician.
04/2016 – This page was updated and approved by an affiliated pediatric physician at the Children’s Heart Program.