What is Vascular Aortic Arch Ring?
A vascular ring is a medical condition where the windpipe (trachea) and the food pipe (esophagus) are surrounded by blood vessels or leftover remnants from these structures.
When talking about the aorta, which is the main artery that carries blood away from your heart to the rest of your body, the part of it that runs horizontally across the body is called the transverse aortic arch. This section has three branches: the brachiocephalic artery, the left common carotid artery, and left subclavian artery. Under normal circumstances, the brachiocephalic artery splits further into two arteries, the common carotid artery on the right side of your body and the right subclavian artery.
The side of the aortic arch is determined by which bronchus (a tube leading from the windpipe to the lungs) it crosses. This means the left aortic arch will be on the left side of the trachea, and the right aortic arch will be on the right side of the trachea.
Sometimes, while the body is developing in the womb, the structure of the aortic arch might not form quite as it should. These changes can result in a variety of different anomalies, or abnormalities, of the aortic arch.
However, there can be minor deviations in the structure of the aortic arch that are still considered normal. Examples include the brachiocephalic artery and the left common carotid artery originating from the same place, and the vertebral artery (which supplies blood to the brain and spinal cord) originating between the left common carotid artery and left subclavian artery.
What Causes Vascular Aortic Arch Ring?
The development of the aortic arch, which is a part of the larger artery that carries oxygen-rich blood from the heart to the rest of the body, starts with the aortic sac. This sac evolves into the right and left parts of the aorta, which later form the aortic arches before ending in right and left large arteries at the back of the body. Each part of the throat involved in early development, which is called a pharyngeal arch, gets its own artery derived from these aortic arches.
These aortic arches, along with their related throat structures, start developing during the 4th to 5th week of pregnancy. However, they don’t all develop at the same time. They appear from top to bottom, and initially there are 6 aortic arches that connect the front and back large arteries. One of these arches, the fifth one, either never forms or partially forms and then recedes. The first arch mainly disappears, leaving only a small portion that forms the maxillary artery that supplies blood to the face, jaw, and other parts of the head. Similarly, the second arch largely goes away, but not before forming blood vessels serving the bones in the ear and lower jaw. The third, fourth, and sixth arches remain prominent, giving rise to the blood vessels of the aortic arch as well as to the large artery that carries oxygen-rich blood from the heart to all parts of the body.
Different parts of the aorta and related arteries originate from various parts of the developing aortic arch. The right part of the aortic sac gives rise to the main artery of the arm and head on the right side, while the left part becomes the start of the aortic arch. The third arch forms common carotid arteries, which are the main arteries that supply blood to the head and neck, as well as to potential arteries of the face and forehead and the start of the main artery running down the neck supplying the brain. The fourth arch on the left side becomes the arch between the main artery for the left head and neck and the main artery for the left arm, while the fourth arch on the right side becomes the start of the main artery for the right arm.
The sixth arch on the left side becomes the start of the artery that brings blood to the left lung, as well as to the vessel that usually closes shortly after birth but may in some cases remain open (ductus arteriosus). The sixth arch on the right side becomes the start of the artery that brings blood to the right lung and the end part of it disappears.
The large artery running down the back of the body on the right side turns into the main artery for the right arm, while the left counterpart develops into the left aortic arch beyond the main artery for the left arm. This same artery also contributes to the formation of the main arteries that run down the neck and supply the brain on both sides. Meanwhile, different sections of the artery at the back of the body between the third and fourth arches, and on the right side also disappear.
The seventh arteries that are part of the series of small arteries supplying blood to various parts of the body become the distal, or end portions of the main arteries for the right arm and left arms, respectively.
This information about embryological development is key to making sense of the formation of vascular rings, which can occur due to various irregularities in the development of the aortic arch.
Risk Factors and Frequency for Vascular Aortic Arch Ring
Aortic arch anomalies, which are irregularities in the large blood vessels branching out from the heart, aren’t very common. They make up about 1 to 3 percent of all cases of congenital heart disease. Men are more likely to have one type of these anomalies, known as a vascular ring, than women. In fact, males have a 1.4 to 2 times higher risk.
There are several types of aortic arch anomalies that can cause a vascular ring. But, the two most common types account for more than 90% of all cases. Here are some of them:
- Double aortic arch (DAA)
- Right-sided aortic arch (RAA) with aberrant left subclavian artery (LSCA) and left patent ductus arteriosus (PDA)
- Circumflex aortic arch, which can either be a left-sided aortic arch with a right descending aorta and right-sided PDA or a right-sided aortic arch with a left descending aorta and left-sided PDA
- Pulmonary artery sling, which technically isn’t a true vascular ring and therefore is called a vascular sling because it goes in front of the esophagus and behind the trachea
- Left-sided aortic arch (LAA) with aberrant right subclavian artery (RSCA), but this only counts if there’s a right-sided PDA
- Right-sided aortic arch (RAA) with mirror image branching, again, this only applies if a left-sided PDA comes out from the descending aorta
Signs and Symptoms of Vascular Aortic Arch Ring
An aortic arch anomaly is a complex condition that requires careful attention for accurate diagnosis. It can be suspected in an infant or child who has long-standing symptoms with no clear cause, despite multiple visits to lung or stomach specialists. The symptoms of this anomaly can vary broadly depending on the severity and can affect the respiratory, gastrointestinal, and cardiac systems.
The symptoms often associated with an aortic arch anomaly include:
- Respiratory: Wheezing, stridor (high-pitched, constricted-sounding breath), pneumonia, respiratory infections, difficulty breathing, cough, bluish skin or lips due to lack of oxygen. Rarely, the anomaly can cause breathing to stop, choking, and inflammation of the small airway in the lungs. Extremely rare symptoms include periods when the child stops breathing, floppy windpipe, and inhaling food into the lungs.
- Gastrointestinal: Vomiting, inability to gain a healthy amount of weight, difficulty swallowing, and choking when eating.
- Cardiac: Abnormal heart sounds (murmurs) and heart failure.
The physical exam findings depend on how severely the trachea (windpipe) and oesophagus are being squeezed by the vascular ring, that is an abnormal formation of the aorta. In babies, this pressure can cause a condition where the trachea or bronchial tubes are too soft or floppy. This leads to symptoms such as “noisy breathing,” which may be heard as a high-pitched, musical sound when your child breathes in and occasionally a low-pitch sound that comes from the chest during expiration, and these usually worsen with agitation.
If the pressure increases, signs of breathing difficulties become more noticeable: flaring of nostrils, retractions (skin pulling in between the ribs or below the ribcage), fast breathing, low oxygen levels in the blood, and a bluish tint to the skin or lips.
Testing for Vascular Aortic Arch Ring
Chest X-ray
A chest X-ray can be useful in identifying any issues with the lungs or heart. This X-ray usually includes two different views (from the back and from the side). If there is a condition called a vascular ring, which is a rare abnormal formation of the aorta or its branches, it would show up as a curve in the windpipe on the side view of the X-ray.
Computed Tomography or Magnetic Resonance Angiography
Advanced imaging tests like a Computed Tomography Angiography (CTA) or Magnetic Resonance Angiography (MRA) might be used for a more detailed look at the vascular ring from all angles.
A CTA can provide a high-quality view of the airways, but the downside is that it involves exposure to radiation. MRA, on the other hand, doesn’t use radiation, but it can take longer and may require you to be sedated or under anaesthesia.
Echocardiography
Echocardiography, which uses sound waves to create images of your heart, can also help detect vascular abnormalities if conducted by a skilled technician. This test is typically performed before surgery to confirm the presence of any heart defects. The main advantage is that it is non-invasive, readily available, and doesn’t involve radiation. The downside is that it might not successfully identify all the abnormal segments and can also be affected by obstacles blocking the sound waves.
Bronchoscopy
Bronchoscopy involves inserting a small, flexible tube with a light through the nose or mouth to view the airways. It’s not really helpful in identifying vascular rings, but some doctors might use it before surgery to determine the level of compression in the airways to aid in placing a breathing tube. It may also be used to rule out other reasons for blockages in the upper airways.
Barium Swallow
A Barium Swallow involves drinking a liquid that contains barium before having X-rays to highlight the esophagus and stomach. This test used to be done when doctors suspected vascular rings, but is no longer commonly used since it is not as effective as CTA or MRA, and doesn’t clearly show the anatomy of the vascular ring. When it does show something, a dip on the back side of the esophagus might suggest a vascular ring, while a dip on the front could point to a pulmonary vascular sling, which is a rare kind of vascular ring.
Treatment Options for Vascular Aortic Arch Ring
When a patient has certain conditions that cause symptoms due to physical pressure, there are no medications that can provide relief. The only effective treatment in such cases is surgery. Surgery is typically only recommended when the patient is experiencing symptoms.
For the condition known as Right Aortic Arch with Aberrant LSCA, surgical treatment involves a left-sided surgical cut (known as a posterolateral left thoracotomy). During the procedure, the surgeon divides a vessel called the Patent Ductus Arteriosus (PDA), or a rigid blood vessel (ligamentum), which relieves the pressure causing the symptoms. Sometimes, a balloon-like pouch (diverticulum) of Kommerell – if it’s large – is also removed to avoid the need for another surgery in the future due to persistent or recurring pressure symptoms on the esophagus or trachea.
Another condition, called Double Aortic Arch, is managed by determining the point of surgical division using preoperative imaging. This is usually a rigid (atretic) segment in the smaller of the two arches, which is most often the left-sided arch. A left-sided posterolateral thoracotomy is performed where the ligamentum or ductus needs to be divided to relieve symptoms.
For Pulmonary Artery Sling, the patient is placed on a machine to support the heart and lungs function (cardiopulmonary bypass), and the surgeon accesses the area through a midline sternotomy approach (incision in the center of the chest). In patients with pressure on the outside of the trachea without fixed narrowing, relocation of the left pulmonary artery to the front of the trachea is done. If there is a complete ring of the trachea, the affected portion is usually removed.
Recent advancements have led to alternative surgical techniques, including video-assisted thoracoscopic surgical techniques and endoscopic robotic-assisted surgical techniques. These new methods, being used in advanced treatment centers, show promising initial results, including shorter hospital stays.
What else can Vascular Aortic Arch Ring be?
If you’re experiencing issues related to the ear, nose, and throat, the problem could potentially be due to various factors. These may fall under different categories such as:
- Otolaryngology: This could include birth defects or abnormalities that have developed in the larynx (voice box).
- Respiratory: Conditions like asthma, frequently occurring pneumonia, or issues related to your breathing like a fistula (an unwanted connection between two body parts) between the trachea (windpipe) and esophagus (food pipe), softening of the trachea (tracheomalacia), or birth defects in the trachea could be the cause.
- Gastrointestinal: Your symptoms might be related to gastroesophageal reflux disease (a condition in which stomach acid frequently flows back into the esophagus) or disorders affecting the motility (movement ability) of your esophagus.
- Others: Alternatively, there might be something pressing on your trachea or esophagus, like a growth or mass in the chest cavity – an example of this could be Hodgkin’s lymphoma (a type of cancer).
Identifying the root cause of your symptoms will help in determining the correct course of treatment.
What to expect with Vascular Aortic Arch Ring
In kids with a condition called ‘vascular rings’, surgery doesn’t typically result in any deaths. The few reported cases where death occurred were usually because the child also had congenital heart disease (a heart condition present since birth) or an underlying lung disease.
Post-surgery, over 70% of patients stop showing symptoms within a year. However, some patients can experience breathing difficulties for about four to six months following the surgery.
The chance that a child will need another operation is quite low, at just 8%. This usually happens if the original issues, such as the diverticulum, aortic arch abnormalities, scarring, or tracheobronchomalacia (a condition where the windpipe walls are weak) are still present and require aortopexy (a surgical procedure to stabilize the aorta – the main blood vessel).
Possible Complications When Diagnosed with Vascular Aortic Arch Ring
Some common complications that can occur include:
- Damage to the recurrent laryngeal nerve leading to vocal cord paralysis
- Thoracic duct injury that may result in a condition called chylous pleural effusion
- Blood vessel issues, like their narrowing, bleeding, and clot formation
- Injury to the windpipe (trachea) and food pipe (esophagus)
Preventing Vascular Aortic Arch Ring
If you have abnormal development of the aortic arch – the main artery in your heart – your doctor will talk to you about the possibility and risks of having a ‘vascular ring’. This is a rare condition where the vessels in your heart form a ring around your windpipe and food pipe. Advanced imaging methods, like CT scans or MRIs, will be needed to confirm this. If the test results show that you don’t have the condition, that’s a relief and you won’t need to worry about it.
On the other hand, if the imaging does show a vascular ring, your doctor will guide you through the necessary steps. They will tell you what symptoms you need to be mindful of and discuss when surgery might be required. They will also ensure you are followed up properly after the surgery to make sure your symptoms improve. This guidance is crucial to ensure your health and well-being as you deal with the condition.
