Hi everyone. Welcome back to Stay Current podcast. I'm, I'm Tom Bash. I am Brittany Levy. We are research fellows at Cincinnati Children's Hospital Medical Center. And along with Stay Current, we share knowledge to improve child health around the globe. In this podcast, we're going to talk about vascular ring anatomy, diagnostic workup and management with Dr. Karl Backer. I'm Doctor Becker. I am a professor of surgery and I work both at Cincinnati Children's Hospital and at Kentucky Children's Hospital. We have a lot to cover today. So if you're looking for a specific part like diagnosis or treatment options, make sure the checkout time stops in the description. They'll take you wherever you need. First, we start basic. And so we asked Doctor Backer, what is a vascular ring? Little did we know this is anything but a basic topic. In general terms, a vascular ring is a group of blood vessels that encircle and compress the trachea and the esophagus, and there's a wide variety of vascular rings. So to Down further, we decided to start with each of the four main categories. Double aortic arch, right aortic arch, pulmonary artery sling, and a nominate artery compression. First, let's talk about the double aortic arch. So the double aortic arch is probably the classic vascular ring, and that's the first one that was ever repaired by Doctor Gross at Boston Children's in the 1940s. Next, Doctor Becker will explain how vascular rings anatomically develop in utero. Out of it's hard to visualize the anatomy, especially a challenging one like embryologic development of the heart. For this reason, we added some illustrations linked below in the description. Don't forget to check them out. I promise it'll help you understand the concept better. In development, there are two aortic arch systems, a right arch and a left arch. In most humans, the right arch involutes and you are left with what we consider a normal anatomic left arch, which is anterior and to the left of the trachea. In patients with a double aortic arch, the right arch persists. And so you have both a left arch and a right arch, and they encircle. They start out anterior, and then They split. The right arch goes to the right, the left arch goes to the left, and then they join again posteriorly after they've gone around both the trachea and the esophagus. So that is a classic through what we think of a vascular ring, where there's actually vascular structures with blood flowing in them and circling both the trachea and the esophagus. The next one is the right aortic arch. If the left arch involutes while the right arch persists, then you Only have a right aortic arch. The issue with the right aortic arch is that it tends to start on the right side of the trachea and esophagus, and then in some cases migrates over to the left side. So basically, it wraps around the trachea and the esophagus, kind of like a hook. More importantly, many of those patients have a left ligamentum. So everyone has a patent ductus arteriosis, which becomes ligamentum, and if that ligamentum is typically on the left side because it connects to the left pulmonary artery. If you have a right aortic arch with a left ligamentum, then you have a vascular structure encircling the trachea and the esophagus. Although the ligamentum typically doesn't have blood flowing in it, it still creates that ring. Double aortic arch tends to be a tighter ring because it's got pulsatile blood on all sides. The right aortic. The arch tends to be a little bit less pathologic, and they develop their symptoms a little bit later in life. The Third structure that we consider a vascular ring, although it's not truly a complete ring, is the pulmonary artery sling. This was first described by Willis Potts in Chicago, where I trained and worked for a long time. In this case, the left pulmonary artery takes its origin from the right pulmonary artery instead of the main pulmonary artery. And then passes posterior to the trachea, but anterior to the esophagus. So it passes between the trachea and the esophagus en route to the left lung. And as it wraps around the trachea and right main stem bronchus, it tends to compress the trachea and the bronchus at the same time. And these patients most frequently present with respiratory distress. The other interesting feature about pulmonary artery sling is that about 2/3 of these patients will have associated tracheal stenosis. Trachea is smaller than normal because the trachea has complete tracheal rings rather than U-shaped rings with a posterior membranous septum. So these patients can present very ill in the newborn period with a combination of the left pulmonary artery pushing on the tracheal bronchial tree and having stenosis of the distal trachea and bronchus from these complete tracheal rings. The fourth type is in the artery compression, not a vascular ring, but in some patients. Patients for whatever reason, the innominate artery tends to take off further along the aortic arch, more to the left, and then when it crosses to the right to transmit the right carotid and right subclavian artery, it wraps in front of the trachea and compresses the trachea anteriorly. And these patients tend to present with noisy breathing and stridor in the first couple of months of life. Almost all of the patients that I've operated on for a nominent artery compression syndrome have been less than one year of age. So, how common are vascular rings and what should we know about epidemiology? Overall, they're relatively uncommon. When I was in Chicago, we had a pretty large series of vascular rings. It was about 400 patients, but over about a 60-year period. So the main freestanding children's hospital in a large metropolitan area that works out to about 8 patients per year with a vascular ring. I would say that in the more recent decade, we were operating on more like 10 to 12 patients a year, but again, we were in a major metropolitan area and that we were a center that was known for vascular ring surgery, so we would get referrals from other parts of the country, not just our local referral base. Dr. Backer knows with vascular rings, you have to have a high index of suspicion when evaluating a patient. So when you have a patient with noisy breathing or stridor or a cough or dysphagia, a lot of the patients that I would see would have been previously Diagnosed as having asthma and croup, and they were treated with albuterol and inhalers. Dr. Becker said once the child spent over 300 days in the hospital being treated for asthma and croup, then someone finally stumbled on the diagnosis of a vascular ring. Once the double aortic arch was divided, the child was not hospitalized anymore, but it has to come to your mind as a possible diagnosis. Then we really wanted to know, are there any associated Congenital anomalies or genetic disorders that may be associated with vascular rings. More recently, as we are able to provide genetic microarrays much more easily, there has been an association of 22Q11 and the George syndrome. We learned from Dr. Becker that the great majority of patients he has operated on with vascular rings do not have genetic syndromes that they know of, and they don't tend to have other congenital heart. Defects either. The one exception being that the tracheal stenosis is very frequently associated with pulmonary artery slings. The pulmonary artery sling patients also probably have a little higher incidence of congenital heart defects like atrial septal defects, tetrology of flow, or VSDs. If you look at patients with petrology of flow, the patients with common arterial trunk, about a third of those patients have right aortic arches, but they tend to have the type of right aortic. arch that has mirror image branching, and those patients actually do not have vascular rings. Also, we talked a little bit about the age of presentation and symptoms to keep an eye out for when suspecting a vascular ring in a patient. The most common presentation is in infancy. The key issues in infancy, at least, are usually respiratory, so noisy breathing, stridor, a cough that sounds like a seal barking. Those are the prime. Symptoms and when they breathe, they have retractions. They have head bobbing. They tend to keep their neck hyperextended to try to flatten and straighten out their trachea. Once you see that, it's unmistakable, and I would say that the dysphagia tends to be more of a symptom in older children either when they start taking solid food or for kids that have this thing called the commoral diverticulum, which can get bigger over time and compress the esophagus. Caerral diverticulum occurs in some anomalies of the aortic arch system. It usually refers to the bulbous configuration of the origin of the aberrant left subclavian artery in the setting of a right-sided aortic arch. And like Dr. Backer said, dilation of the commoral's diverticulum results in compression of the surrounding structures, such as dysphagia or dyspnea, or stridor or wheezing, cough, recurrent pneumonia, obstructive emphysema, or even chest pain. They can go undiagnosed and then have trouble when they're adolescents or even young adults. The pulmonary artery sling, these are the patients that can present with severe respiratory distress. They're desaturated. They have severe. Actions and they need to be intubated. Another symptom that patients with pulmonary artery sling can have is hyperinflation of the right lung. Because pulmonary artery sling acts like a ball valve, and air can get into the right lung, but then it can't come out. I've had several patients referred to me because they had quote unquote, absence of the left lung. And the reason was that the right lung was so hyperinflated. It was pushing all of the structures over to the left. And then once They repaired the pulmonary artery sling. The left lung was really a normal left lung. The indominant artery compression, these are the patients that present with severe stridor and noisy breathing. They do not have trouble with swallowing, but interestingly, they can present with apnic episodes. In pulmonary artery sling, the esophagus is compressed anteriorly, and if you have a bolus of food going through, it tends to compress the trachea more, and they get apnic. And the same. Thing with patients with a nominate artery compression syndrome, they can present with episodes of apnea, which is a scary thing for the parents. Then we really needed to know more about the workup and how to make the diagnosis of a vascular ring. I think the first thing is to get a plain chest X-ray, and the chest X-ray, for example, with a double aortic arch, you tend to lose that normal aortic knob on the left side. And again, that's a sign of hyperinflation of the right lung for a pulmonary artery sling. 30 years ago, the next diagnostic procedure would have been a barium swallow, and there are subtle signs on the barium swallow that you can look at where the esophagus is compressed. According to Dr. Backer, radiologists practicing before cross-sectional imaging was popular were really pretty good at interpreting those images and figuring out that it was a right arch or a double arch. But nowadays, the easiest study to get and they instantly tells you what. Whether it's a vascular ring and what type of vascular ring is a CT scan, and the CT scan has to be done with contrast in order to see the vascular structures. Some institutions prefer MRI, and one of the reasons for that is to avoid radiation. But the current scanning protocols with the CT scan really have very low radiation doses, says Dr. Becker. The problem with an MRI is it takes longer, and they often have to have either sedation or general anesthesia, which we try to avoid in children. In babies. The other thing that's on the horizon is that there is now a lot of patients that have fetal diagnosis. So, when the babies have their screening ultrasound while they're in utero, there's a view that looks at the trachea that can tell that the aortic arch is in an abnormal location. And the diagnostic paradigm that they recommend is an echocardiogram at birth. The echo can often tell you if it's a right arch or a double arch, and definitely They can tell you if there's a pulmonary artery slit. And then depending on the baby's symptoms, they decide when you want to get more definitive cross-sectional imaging with a CAT scan. If the baby is symptomatic, you get the CAT scan and then probably operate on the child before they go home from the hospital. If they're not symptomatic, then obtain the CT imaging somewhere between 2 and 4 months of age where they can still be fed and swaddled and then use that diagnostic information to decide what the next steps are. And here we are, management options. How can we treat these patients with different types of vascular rings? For symptomatic vascular rings, we recommend an operation in essentially all patients, and one of the reasons for that is that the outcomes are so good and the patients do so well after the operation. It's actually a very gratifying operation to perform. For patients with a double aortic arch, the standard operation is to divide the smaller of the two arches, and because the right aortic arch is typically dominant, most of Patients are going to be operated on through a left thoracotomy. It's a posterolateral, typically muscle sparing, 3rd or 4th intercostal space, and we don't use a double lumin endotracheal tube because they're too small. We just push the lung anteriorly and then dissect out the structures, and typically the ligamentum should be divided in all cases and then also divide the smaller arch, which is usually the left aortic arch. And the key here is to divide the arch between vascular clamps. And oversew the two stumps with proline suture. In the past, the standard treatment was just to divide the ligamentum, and that can be done either with vascular clamps and over sewing or with ligation and division with both a silk ligature and a prole purse string suture. But a number of these patients have origin again on the left subclavium from the descending thoracic aorta, and it comes out of a thing called a commoral diverticulum. What we found is that a number of these patients would return with Recurrent symptoms is the diverticulum enlarged. So about probably 15 to 20 years, I've been almost routinely resecting the diverticulum and then reimplanting or transferring the left subclavian artery to the left carotid artery. It's definitely a larger operation, but they've had essentially no serious complications, and they've had complete relief of dysphagia after relieving the compression, and the recurrence rate is next to none. The other issue with the commoral diverticulum is that it can enlarge over time and an aneurysm that have all the complications that an aneurysm can have dissection, rupture, etc. The pulmonary artery sling is a very different approach. These patients are operated on through a median stenotomy with cardiopulmonary bypass, and then the left pulmonary artery is disconnected from the right pulmonary artery. We oversew the stump on the right pulmonary artery, and then the left pulmonary artery is brought through that space posterior to the trachea, anterior to the esophagus, up into the left. Medstinum, and then we anastomos the left pulmonary artery to the main pulmonary artery. Typically, the site where you anastomose the pulmonary artery is where the ligamentum resides, and that's usually a pretty good landmark. And often we cut out the area of the ligamentum in the main pulmonary artery, and then that's where the left pulmonary artery is anastomosed to the main pulmonary artery. If they have tracheal stenosis, typically that's the time that we also repair with a slight tracheoplasty. The last one is the inominant artery compression syndrome. There's probably two different. operations that people have done. One strategy is to enter the right chest through a right anterior lateral thoracotomy and then use pledgeted sutures to suspend the indominate artery to the back of the sternum. The other technique is to do a median sternotomy and actually transfer the inominant artery to a spot more right where, not compressing the trachea. Of note, we have a video about this from Dr. Rutter, also from Cincinnati Children's Hospital, so be sure to check it out on the Stay Current app. Coming to the end here, we asked Dr. Backer what he thinks about the future of vascular ring surgical repair. Thoracoscopic intervention for vascular rings has been around for a long time. I think it's fine for a very small isolated number of patients. For example, pulmonary artery sling is not going to be done thoracoscopically. Also, patients with a double aortic arch that have widely patent arch. There is a little bit of danger to doing this thoracoscopically because if the The staple line slips or comes apart, all of a sudden you have the aorta hemorrhaging directly into the left chest. The reality is that there are not very many patients that are actually good candidates for the thoracoscopic intervention, according to Dr. Becker. The other issue is that the thoracoscopic approach would potentially send them home on day one post-op, but often they stay till day 2, so you're not really saving much time. I think the laparoscopic versus open approach is one of the topics that we tackle. All the time on our various podcasts, especially with surgeons like Doctor Todd Ponsky, Steve Rothenberg, and Pablo Lahey as frequent guests. So it's always fun to hear from us. Finally, Dr. Backer, what can we expect as far as the outcomes postoperatively? Most patients have an immediate improvement in their breathing. The patients that have been severely compressed, that have a component of tracheomalacia can take 6 months to 1 year before they come back to normal. Normal. And then a small number of patients continue to have symptoms. Uh, but I would say it's a very small percentage, and most of them are substantially improved by the operation. And then there were the group of patients that didn't have their commoral diverticulum addressed, and we've had to go back. So we actually wrote a paper about re-operations after vascular ring surgery. The real caveat here is to set expectations for patients and their families. It may be a few months before you see complete improvement in the patient's symptoms. That was all regarding vascular rings. Overall, we discussed how different vascular rings occur embryologically based on the double aortic arch hypothesis. Different vascular ring formations can occur, including a double arch, a right arch, a pulmonary sling, and a few others. In these cases, you need to have a high index of suspicion to make the diagnosis, and diagnostic tests have really varied over the years. Years. But currently, cross-sectional imaging such as CT scans or MRIs are the gold standard, along with an echocardiogram. The aim of surgery is to remove the structures encircling the trachea and esophagus to reduce compression and airway compromise. Frequently, this is through an open approach, but in some candidates at specialized centers, a thoracoscopic, minimally invasive approach may be considered. I'm I'm Tom Bash and I'm Brittany Levy. Thank you for listening to this podcast. Don't forget to follow us on social media, subscribe to our YouTube channel and download the Sare app for more content, including videos, podcasts, and infographics. Cincinnati Children's Hospital and Stay Current share knowledge to improve child health around the globe.
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