What is Vascular Ring Double Aortic Arch?
“Vascular ring” (VR) is a term used for structures that wrap around and squeeze your esophagus and windpipe, leading to breathing and digestive symptoms. VRs fall into two major categories: complete and incomplete.
A complete VR entirely circles both the windpipe and esophagus. These include things like a double aortic arch (DAA) and a right aortic arch (RAA) with an aberrantly positioned left subclavian artery (the artery that goes behind the esophagus). These are the most common forms of vascular rings.
An incomplete VR doesn’t fully circle the windpipe and esophagus but can still squeeze them. These could include an abnormally positioned innominate artery, an abnormally positioned right subclavian artery, and a pulmonary artery sling.
Unlike in a normal body where arteries are positioned to the left of the windpipe and don’t go behind the esophagus or trachea, in the case of a VR, there’s an active or remnant blood vessel that loops around these structures.
Depending on the size and position of the aortic arches, the DAA can be classified into three main types. The most common type is the one where the right arch is larger (about 80% of cases). On the other hand, the RAA can be divided into two types, depending on the point of regression of the fourth aortic arch.
A common condition found particularly with the one type of RAA is “Kommerell diverticulum”, named after Dr. Burckhard F Komerell who first described it in 1936. This condition typically refers to a protrusion of the aorta.
There’s also a situation when the left pulmonary artery comes from the right pulmonary artery compressing the windpipe, a condition known as pulmonary artery sling. It’s the only type of VR that causes indentation in the front of the esophagus.
Sometimes, the innominate artery, an artery that usually sits later from the transverse arch, crosses over the windpipe causing its compression.
The International Congenital Heart Surgery Nomenclature and Database Committee has devised a classification system for VR:
A. Complete vascular rings
* Double aortic arch (DAA)
I. Dominant right arch
II. Dominant left arch
III. Equal arches/balanced arches
* Right aortic arch (RAA)
I. RAA+ aberrant left subclavian artery (ALSA)
II. RAA with mirror imaging
B. Incomplete aortic arch
* Innominate artery compression syndrome
* Pulmonary artery sling
* Aberrant right subclavian artery (ARSA).
What Causes Vascular Ring Double Aortic Arch?
The exact cause of DAA (Double Aortic Arch), and other vascular rings (abnormal formations of the aorta and other arteries around the trachea and esophagus), is still unknown. However, it is reported that a deletion in the 22q11 portion of our DNA could be associated with the DAA and RAA (Right Aortic Arch). There’s also been a connection noted between DAA, and chromosomal conditions like trisomy 21 (Down syndrome) and trisomy 18 (Edwards syndrome). Moreover, the existence of a left aortic arch with the right subclavian artery (an artery that carries blood from the aorta to the right arm) originating from the wrong place, although not forming a vascular ring, is highly observed in cases of Down syndrome.
Below are simplified explanations of some complex descriptive diagrams:
1. The first diagram shows a unique feature of a DAA with two “ductus arteriosi” (channels connecting two major arteries in the heart before birth), viewed from top to bottom. This feature was identified in a patient with transposition (a congenital heart defect that changes the positioning of the two main arteries). Both major arches and arteries of the heart were present in this situation. However, this configuration hasn’t been noted in patients with a normal heart structure.
2. The second diagram offers a typical image of a person with a DAA. But there is usually a ductus or ligament on the left. It is rare to find a DAA with a ductus or ligament on the right.
3. The last diagram shows a RAA with an incorrectly placed left subclavian artery (artery behind the esophagus). Here, the fourth aortic arch on the left regresses (shrinks). The order of blood vessels from the ascending aorta is: the left carotid artery (to the head and neck), then right carotid artery, followed by the right subclavian artery, and finally, the incorrectly placed left subclavian artery. The part between the left subclavian artery and the descending aorta is referred to as the diverticulum of Komerell (a pouch near the aorta).
Risk Factors and Frequency for Vascular Ring Double Aortic Arch
A double aortic arch is a rare occurrence, but it is the most common cause of a condition called a vascular ring. This accounts for 55% of cases, while a right aortic arch with an abnormal left subclavian artery makes up 45% of the cases. On the other hand, a right aortic arch is more common in the general population, with an occurrence rate of 0.1%. In cases of a certain genetic deletion (22q11), a double aortic arch is found in 14% of individuals, predominantly right arch dominant, while the right aortic arch occurs in 30% of individuals with the same deletion. It is also reported that this condition is more common in males, who make up around 67% of the cases.
A Kommerell Diverticulum is another rare occurrence and it can present in two ways. The first possibility is a left aortic arch with an aberrant right subclavian artery, which is seen in 0.5% to 2% of the population. The second possible scenario is a right aortic arch with an aberrant left subclavian artery, occurring in 0.05% to 0.1% of the population.
Signs and Symptoms of Vascular Ring Double Aortic Arch
DAA refers to a type of vascular ring, a condition affecting blood vessels around the heart. This mainly impacts babies and young children, frequently revealing itself before a child turns three. Typically, around 91% of patients with DAA display respiratory symptoms, such as:
- Stridor (noisy breathing)
- Wheezing
- Coughing
- Choking
About 40% of patients may show gastrointestinal symptoms, including:
- Choking during feeding
- Difficulty swallowing
- Failure to thrive or slow growth
Additionally, around 30% of patients might exhibit cardiac symptoms like:
- A heart murmur
- Cyanosis (bluish color of skin due to poor circulation)
- Chest pain
Another related condition is RAA with an aberrant left subclavian artery. This is often referred to as a “looser ring.” Individuals with this condition tend to have more difficulty swallowing. As babies, they can typically consume milk without problems, but they start experiencing symptoms when they begin to eat solid foods. Many such patients do not get diagnosed until they are teenagers, as they develop a habit of chewing their food thoroughly to swallow without pain.
Testing for Vascular Ring Double Aortic Arch
Before a baby is born, a condition can be confirmed using a special type of ultrasound called a fetal echocardiogram. After the baby is born, various tests are used to determine which side the problem is on. This is important as it helps doctors decide which side to operate from if surgery is needed.
One of the first tests typically done is a chest X-ray, which can show narrow airways in about 47% of patients and a larger right arch in about 40%. Another test that can be performed is an esophagography or barium swallow, which can identify an irregularity at the back of the food pipe in around 74% of patients.
More advanced imaging techniques such as CT and MRI scans are also used, and they can correctly identify the condition in all cases. Over time, MRI scans have replaced CT angiograms and cardiac catheterization as the primary diagnostic tool in older children, mainly because they are non-invasive. However, the risk of providing general anesthesia to a young child who cannot hold their breath for the duration of the MRI needs to be considered alongside the radiation risk from a CT scan, which can be completed within seconds.
Nowadays, CT scans use less radiation than they used to and are great at providing a detailed view of the branches of the windpipe. Echocardiography with Doppler and color mapping is non-invasive and handy too. It can also check for any additional heart issues before any potential surgery.
Treatment Options for Vascular Ring Double Aortic Arch
Most patients with DAA, or Double Aortic Arch, usually require surgery quite soon – typically around 1.4 months after their first symptoms show up, and about 4.9 months after they first became aware of any issues. The location of the surgery usually depends on which side the smaller arch of the aorta is on. In nearly 71% of patients, it’s the left side.
Surgeons typically perform a procedure known as a lateral thoracotomy, where they make an incision along the side of the chest. The smaller arch is then tied off and divided, followed by dividing the ductus arteriosus or ligament arteriosus , which are vessels found in the heart. During the procedure, the surgeon also fully separates the windpipe (trachea) and food pipe (esophagus) to improve access and visibility.
In some cases where a patient has a bulge in their aorta, known as a Kommerell diverticulum, surgeons might remove the bulge and reroute the left subclavian artery, a major blood vessel, to connect with the left common carotid artery, another key artery that supplies blood to the brain.
There’s also a minimally invasive option that uses video-assisted thoracoscopic techniques. This option allows doctors to divide the vascular ring safely and effectively in children, causing less trauma and potentially improving recovery times.
What else can Vascular Ring Double Aortic Arch be?
When looking at vascular ring symptoms, it’s essential to rule out other conditions that might produce similar effects. These can include:
- Born-with windpipe abnormalities such as tracheoesophageal fistula (abnormal connection between the esophagus and the trachea) or tracheomalacia (weakness and floppiness of the walls of the windpipe)
- Born-with voice box issues like laryngomalacia (softening of the voice box tissues), laryngeal webs (tissue growth across the voice box opening), or cysts
- Possible pressure on the windpipe from an external mass like lymphoma (cancer of the lymphatic system)
- Common conditions like asthma (chronic inflammation and narrowing of the airways), gastro-esophageal reflux (stomach acid flowing back into the esophagus), or recurrent pneumonia (inflammation of the lungs caused by infection).
It’s important to note that distinguishing the vascular ring from these diseases can be a crucial part of diagnosis and subsequent treatment.
What to expect with Vascular Ring Double Aortic Arch
The outlook is very good, with roughly 26 out of 300 patients requiring a second surgery. Many studies have shown that there were no deaths either soon after the surgery or later on. However, a few studies reported a single death.
Possible Complications When Diagnosed with Vascular Ring Double Aortic Arch
After surgery, complications are not common but they can occur. Roughly 9% of patients may develop a condition known as chylothorax, 4% may experience short-term high blood pressure, and around 3% may end up with a vocal cord issue resulting in weakness or paralysis. In a single study, some individuals developed a serious condition called an aortoesophageal fistula- a hole between the heart artery and the esophagus. This causes severe bleeding in the guts, which can be temporarily relieved with a special medical procedure involving an esophageal balloon catheter until surgery can be done.
After the operation, it is common for patients to continue experiencing trouble with noisy, difficult breathing, known as stridor, for some time. This is due to the windpipe not having had the chance to develop correctly during fetal growth or after birth. It takes a while for the patient’s windpipe to become stronger, and in some cases, another surgery might be needed to lift the major artery away from the windpipe.
Post-operation Complications:
- Chylothorax (experienced by around 9% patients)
- Transient hypertension (short-term high blood pressure, around 4%)
- Vocal cord weakness/paralysis (in about 3% of cases)
- Aortoesophageal fistula (serious condition causing severe gut bleeding)
- Continued stridor issues (noisy, difficult breathing)
- Possible requirement for additional intervention to rectify windpipe issues
Preventing Vascular Ring Double Aortic Arch
Patients typically spend around 2 days in the Intensive Care Unit (ICU) – a special area for critically ill patients – after their surgery. They are then usually discharged from the hospital altogether between 5 to 8 days post-surgery. According to a study, most patients do not experience any persistent symptoms following their surgery. That being said, other studies have found that many patients do continue to experience respiratory issues – such as difficulties with breathing. These ongoing issues are often due to a condition called tracheomalacia (a weakening and collapsing of the windpipe) and tracheostenosis (a narrowing of the windpipe). Both of these conditions can be caused by abnormal development of the windpipe.
