Vascular rings and slings

INTRODUCTION — Vascular rings are congenital anomalies of the aortic arch that result in compression of the tracheobronchial tree and/or esophagus, leading to respiratory and gastrointestinal symptoms. They can be classified as either complete (when both the trachea and esophagus are fully encircled by a vascular anomaly) or incomplete (without full encirclement of both structures).

The different forms of vascular rings and slings and their clinical manifestations, diagnosis, and treatment are discussed here.

ANATOMY

Embryology — Beginning at the fourth week of embryogenesis, the aortic arch develops from six symmetrical paired aortic arch vessels and the paired dorsal aortae. During the next few weeks of embryogenesis, remodeling and rearrangement of these structures result in the formation of the normal left aortic arch [1,2].

●Right and left third arches persist as the right and left carotid arteries

●Left fourth arch persists as the transverse arch

●Left sixth arch persists as the ductus arteriosus

●Right and left subclavian arteries arise from the seventh intersegmental arteries along the posterior body wall and are remodeled into the final aortic arch

Abnormal development of this complex vascular remodeling process results in malformations, which lead to the different forms of vascular rings, slings, and other anomalies [2,3].

Left aortic arch

●Normal anatomy – The normal left aortic arch crosses over the left mainstem bronchus and typically descends along the left side of the spine. The aortic arch gives rise to three vessels:

•Innominate (or brachiocephalic) artery, which bifurcates into the right common carotid artery and the right subclavian artery

•Left common carotid artery

•Left subclavian artery

The ductus arteriosus arises from the undersurface of the arch opposite the origin of the left subclavian artery. Following birth, it involutes into the ligamentum arteriosum.

●Anatomic variants – There are a few anatomic variants of aortic arch branching that are not associated with any symptoms and include the following:

•A common brachiocephalic trunk trifurcates into the right subclavian, right common carotid, and left common carotid arteries. This variant is commonly called a "bovine trunk," though it does not reflect the arch anatomy of cattle.

•Four vessels can arise directly from the arch with two different patterns:

-In addition to the usual three vessels, a vertebral artery can arise from the arch between the left common carotid and the left subclavian.

-An aberrant right subclavian artery can arise posteriorly to the left subclavian artery and cross posterior to the esophagus; if the ductus arteriosus is left-sided, there is no compression of the trachea or esophagus [4].

Right aortic arch — A right aortic arch crosses the right mainstem bronchus and descends along the right side of the spine. Rarely, the arch crosses the midline posterior to the esophagus above the level of the carina, then descends along the left side of the spine, which is termed a circumflex retroesophageal right aortic arch [5].

Right aortic arches with mirror-image branching do not cause compression upon the trachea or esophagus, because the ductus arteriosus either arises from the undersurface of the arch opposite the right subclavian artery (true "mirror-image") or from the bifurcation of the innominate artery and then takes an anterior course in the mediastinum to the pulmonary artery without compromising the trachea or esophagus.

Vascular rings — Vascular rings completely encircle the trachea and esophagus and are commonly associated with significant symptoms [4,6,7]. The majority of reported cases (90 percent) in retrospective reviews and case series are due to either a double aortic arch, or a right aortic arch and an aberrant left subclavian artery and left-sided ductus arteriosus [4,6-9]. However, any configuration with a contralateral descending aorta or diverticulum or dimple will create a vascular ring.

Double aortic arch — In double aortic arch, the paired aortic arch arteries fail to remodel appropriately, which results in two aortic arches both connecting the ascending and descending aortas. The ascending aorta bifurcates anteriorly to the trachea and esophagus, with one arch coursing to the left of the trachea and esophagus and the other to the right (figure 1). The arches rejoin into a single (typically left) descending aorta posterior to the trachea and esophagus, thereby completely encircling the two structures.

Typically, the right arch is larger and more cephalad in its course and the left arch is smaller and more caudally located. If the left arch becomes atretic, a small stump may remain on the descending aorta.

The right common carotid and right subclavian arteries arise from the rightward arch, and the left common carotid and left subclavian arteries arise from the leftward arch. The ductus arteriosus most commonly arises from the left arch, but it may arise from either arch or both arches. There may be atretic segments of the arches, which must be identified prior to surgical repair.

Right aortic arch with aberrant left subclavian artery and left-sided ductus arteriosus/ligamentum — In a right aortic arch with an aberrant left subclavian artery and left-sided ductus arteriosus or ligamentum, the ductus arteriosus arises posteriorly in the mediastinum at the origin of the aberrant left subclavian artery, courses anteriorly to the left of the trachea and esophagus, and connects to the pulmonary artery (figure 2). The trachea and esophagus are completely encircled by the right-sided aortic arch (anterior/rightward), the base of the left subclavian artery (posterior), and ductus arteriosus (leftward), resulting in a complete vascular ring.

In many cases, the left subclavian artery and ductus arteriosus arise from the diverticulum of Kommerell, a vascular structure derived from a remnant of the embryonic fourth aortic arch with a similar diameter to the descending aorta and a larger diameter than the left subclavian artery. This vascular structure may cause posterior compression of the esophagus and trachea, and, if it is not fully resected at the time of surgery, may continue to produce symptoms after surgical division of the vascular ring [3,10-13]. A clinically significant diverticulum is often defined as a dilated origin of the left subclavian artery >1.5 times the size of the distal subclavian artery [3].

Other causes — Other rare causes of complete vascular rings include the following:

●Left aortic arch with a right descending aorta and right ductus arteriosus (or ligamentum)

●Right aortic arch with a left descending aorta and left ductus arteriosus (or ligamentum)

●Left aortic arch with an aberrant right subclavian and a right ductus arteriosus (or ligamentum)

●Right aortic arch with mirror-image branching and a left ductus arteriosus (or ligamentum) arising from a retroesophageal dimple pointing to the left (also described as a double aortic arch with atretic left arch)

●Right aortic arch with retroesophageal left innominate and either a left ductus arteriosus or diverticulum

Other vascular anomalies — Vascular anomalies that do not completely encircle the trachea and esophagus are often asymptomatic and are found incidentally. However, they can compress the tracheal bronchial tree and/or esophagus, leading to respiratory or gastrointestinal symptoms.

Pulmonary artery sling — Pulmonary artery sling is a rare vascular anomaly in which the left pulmonary artery arises from the right pulmonary artery (late bifurcation of the branch pulmonary arteries). The aberrant left pulmonary artery passes between the trachea and the esophagus prior to entering the left lung, leading to compression of the trachea and/or esophagus. Pulmonary artery sling is frequently associated with complete tracheal cartilaginous rings; therefore, these patients should have a careful airway assessment (image 1). (See "Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula", section on 'Congenital tracheal stenosis'.)

Innominate artery compression syndrome — This syndrome occurs when the innominate (or brachiocephalic) artery originates later along the course of the transverse arch, resulting in takeoff to the left of the trachea. Anterior tracheal compression with associated tracheomalacia results when the aberrant innominate artery passes back to the right.

INCIDENCE — Aortic arch anomalies are rare malformations accounting for approximately 1 to 3 percent of congenital heart disease [2,14]. Males have a 1.4 to 2 times greater risk of having a vascular ring compared with females [4,6,7].

Published reports are primarily observational case series of patients with vascular rings treated by surgical repair at tertiary centers [4,6-9]. As a result, complete vascular rings, which are more commonly associated with significant symptoms, represent the majority of cases. In the available case series, the relative frequencies of different malformations were as follows [4,6,7,15]:

●Right aortic arch and an aberrant left subclavian artery and left-sided ductus arteriosus – 30 to 65 percent of cases

●Double aortic arch – 25 to 45 percent of cases

●Innominate artery compression syndrome – 3 to 20 percent of cases

●Aberrant left subclavian artery – 3 to 7 percent of cases

●Pulmonary artery sling – <5 percent of cases

CLINICAL MANIFESTATIONS

Presenting symptoms — For patients with symptomatic vascular rings, the parents/caregivers often report "noisy breathing" in the infant from birth. In the available case series, which largely included severely affected patients undergoing surgical repair, most patients present by one year of age with significant tracheal and/or esophageal symptoms [4,6-9]. In a series of 200 patients with vascular slings managed at a single center, 56 percent presented primarily with respiratory symptoms, 11 percent presented primarily with esophageal symptoms, and 32 percent had both respiratory and esophageal symptoms at presentation [16].

●Respiratory symptoms – Patients with complete vascular rings or pulmonary artery sling most often present with respiratory symptoms due to tracheal compression and associated tracheobronchomalacia [2,4,6-9,15]. Common symptoms include:

•Stridor

•Wheezing

•Cough

•Respiratory distress

•Frequent respiratory infections

●Esophageal symptoms – Esophageal complaints are also common, including:

•Dysphagia

•Feeding difficulty

•Vomiting

●Variability in presentation – The clinical presentation of vascular rings and slings varies from critical airway obstruction in neonates to incidental diagnosis in otherwise asymptomatic adults [17]. A complete double aortic arch presents earlier than other forms of vascular rings, typically within the first few weeks of life. Pulmonary artery sling may present immediately after birth with severe respiratory distress. Patients with incomplete vascular rings are often asymptomatic.

Associated anomalies — Associated anomalies are common in children with vascular rings, with a reported prevalence of up to 50 percent [6,11,18].

●Cardiac anomalies – Associated cardiac defects may include ventricular septal defect, tetralogy of Fallot, coarctation of the aorta, or patent ductus arteriosus [6,11].

●Noncardiac anomalies – Noncardiac anomalies include tracheoesophageal fistula, cleft lip/palate, subglottic stenosis, and genetic or malformation syndromes (eg, DiGeorge syndrome [19], Down syndrome, or CHARGE syndrome). (See "DiGeorge (22q11.2 deletion) syndrome: Epidemiology and pathogenesis" and "Down syndrome: Clinical features and diagnosis".)

Physical examination — Physical findings vary depending upon the degree of tracheal and esophageal compression.

Infants with significant airway compression and associated tracheobronchomalacia are often noted to have stridor and/or wheezing that worsen with agitation.

Severely symptomatic infants display signs of increased respiratory effort and/or distress that include nasal flaring, intercostal retractions, tachypnea, or intermittent cyanosis. Some infants will lie with their back arched and neck extended to minimize tracheal compression. Wheezing and/or coarse upper airway sounds may be heard during auscultation.

EVALUATION

Clinical suspicion and general approach — The clinician must have a high degree of suspicion to diagnose a vascular ring since it is a relatively uncommon cause of respiratory distress. The history and physical examination help to distinguish vascular rings from other diagnostic possibilities. A history of prolonged and recurrent respiratory difficulties and dysphagia is suggestive. Assessment of the sidedness of the aortic arch on chest radiograph is also helpful, but, ultimately, additional evaluation with computed tomography angiography (CTA), magnetic resonance angiography (MRA), echocardiography, and/or bronchoscopy is necessary to establish the diagnosis.

Our suggested approach to evaluating infants and children with suspected vascular rings is as follows:

●The initial study is a chest radiograph to evaluate for pulmonary pathology and the sidedness of the aortic arch.

●This is followed by both of the following:

•Echocardiography to identify the arch branching pattern and intracardiac anatomy. (See 'Echocardiography' below.)

•Advanced imaging with CTA or MRA to define the vascular anatomy. As discussed below, we prefer CTA over MRA because of the rapid image acquisition without the need for sedation. However, some centers may prefer MRA. (See 'Computed tomography and magnetic resonance angiography' below.)

●Bronchoscopy is not routinely performed but is reserved for patients who exhibit significant signs/symptoms of airway obstruction. (See 'Bronchoscopy' below.)

●Barium esophagograms are generally not necessary, as they do not provide additional information beyond that obtained by advanced axial imaging. (See 'Barium swallow' below.)

Diagnostic modalities — Chest radiographs including posterior-anterior and lateral views should be the initial study to identify the underlying cause of respiratory symptoms. Magnified high-kilovoltage airway films may be useful to identify a significantly compressed trachea. Anterior bowing of the trachea in the lateral view is suggestive of a vascular ring.

Following chest radiography, several diagnostic procedures are available in the evaluation of a child with a suspected vascular ring. The choice and sequence of these tests varies between centers, depending on the local expertise, experience, cost, and available technology [2,6,20].

Computed tomography and magnetic resonance angiography — CTA and MRA provide three-dimensional visualization of the vascular anatomy, which accurately makes the diagnosis of a vascular ring and gives detailed anatomic information needed to plan the operative procedure [21,22].

There are advantages and disadvantages of each modality. CTA exposes the child to ionizing radiation, but, with modern dual-source multidetector scanners, a study may be completed quickly (thus limiting the need for patient sedation) and with reduced radiation exposure. For a child who is awake and breathing spontaneously, CT may provide a better preoperative assessment of the airway. MRA does not involve exposure to radiation, but image acquisition is longer (30 to 60 minutes) and sedation or anesthesia may be necessary, particularly for infants and young children.

Many centers use CTA and/or MRA to assess all patients with vascular rings [4,6,11], whereas, in some centers, the use of these modalities is limited because of associated costs and potential complications [7]. The choice of imaging modalities depends on institutional expertise and preference [4,6,7,11,20,21,23].

Echocardiography — Echocardiography is often used as a complementary diagnostic test to identify any associated cardiac lesions [4,6-9,11]. In experienced hands, echocardiography can clarify vascular anatomy and visualize vascular rings [24]. The advantages of this imaging modality are that it is noninvasive, readily available, and does not expose the child to ionizing radiation. Disadvantages are that echocardiography cannot detect atretic segments without patent lumens and thus is less reliable in defining arch anatomy compared with CTA or MRA, it poorly visualizes the airway, and (in some patients) the examination is limited due to diminished acoustic windows.

Bronchoscopy — Bronchoscopy is often used to determine the cause of upper airway symptoms [15]. In children with vascular rings, it will indicate the level of compression and will assess the degree of associated bronchomalacia. However, it cannot determine the vascular anatomy or the presence of additional cardiac anomalies.

Bronchoscopy is an invasive procedure and may worsen the child's symptoms because of tracheal edema. Nevertheless, some patients, based upon presenting symptoms, may have first been evaluated by an otorhinolaryngologist or pulmonologist, who may perform bronchoscopy as part of the initial evaluation. (See 'Differential diagnosis' below.)

Adjunctive intraoperative bronchoscopy may be useful to evaluate the efficacy of ring division in relieving tracheal compression and may guide decisions about the need for further intraoperative maneuvers (aortopexy, tracheopexy). In particular, patients with pulmonary artery slings almost always require bronchoscopy, given the high incidence of complete tracheal rings requiring specific intervention [3]. However, the use of bronchoscopy varies between centers, with some routinely using it in the preoperative or intraoperative setting, while other centers perform bronchoscopy more selectively [6,11]. (See 'Surgery' below.)

Barium swallow — Barium contrast esophagogram (barium swallow) has largely been replaced by CTA and MRA in the evaluation of children with suspected vascular rings. Barium swallow demonstrates a posterior indentation of the esophagus in all vascular rings except for the pulmonary sling, in which an anterior indentation and increased space between the trachea and esophagus are found. However, the precise vascular anatomy or the presence of another cardiac anomaly cannot be determined by esophagogram.

DIAGNOSIS

Antenatal diagnosis — Several studies have shown that antenatal diagnosis can be initially made by fetal ultrasound, though confirmatory imaging after delivery is required [25-30]. In these case series, isolated vascular rings were diagnosed using "3-vessel and trachea" and "supra-aortic branch" views. Antenatal detection rates have increased with advances in prenatal imaging. In the modern era, approximately 50 to 60 percent of cases are diagnosed prenatally, whereas, in the early 2000s, only 10 to 20 percent of cases were diagnosed prenatally [31,32]. In one study, prenatal diagnosis was associated with earlier age at surgical intervention and lower likelihood of residual symptoms after surgery [32].

Postnatal diagnosis — The postnatal diagnosis of vascular rings is established with computed tomography angiography (CTA) or magnetic resonance angiography (MRA), which provide detailed anatomic information to determine the specific type of vascular anomaly. (See 'Computed tomography and magnetic resonance angiography' above.)

DIFFERENTIAL DIAGNOSIS — The differential diagnosis of vascular rings includes other conditions that can present with similar respiratory and esophageal complaints [4]. Appropriate imaging studies (eg echocardiography, computed tomography angiography [CTA], magnetic resonance angiography [MRA]) differentiate vascular rings from these conditions:

●Tracheoesophageal fistula, tracheomalacia, and other congenital tracheal anomalies (see "Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula")

●Congenital and acquired laryngeal abnormalities (eg, laryngomalacia, laryngeal webs or cysts, subglottic stenosis, subglottic hemangioma, vocal cord paralysis or polyps) (see "Congenital anomalies of the larynx")

●Asthma (see "Asthma in children younger than 12 years: Initial evaluation and diagnosis")

●Gastroesophageal reflux (see "Clinical manifestations and diagnosis of gastroesophageal reflux disease in children and adolescents")

●Recurrent pneumonia (eg, due to swallowing dysfunction and recurrent aspiration) (see "Aspiration due to swallowing dysfunction in children")

●Esophageal motility disorders (see "Achalasia: Pathogenesis, clinical manifestations, and diagnosis" and "Distal esophageal spasm and hypercontractile esophagus")

●External compression of the trachea and/or esophagus by a mediastinal mass (eg, lymphoma) (see "Clinical manifestations, pathologic features, and diagnosis of precursor T cell acute lymphoblastic leukemia/lymphoma")

The approaches to evaluating children presenting with stridor, recurrent wheeze, and dysphagia are detailed in separate topic reviews. (See "Assessment of stridor in children" and "Evaluation of wheezing in infants and children" and "Evaluation of acute dysphagia in children".)

TREATMENT

Surgery — The only definitive treatment is surgery, which was first described by Gross in 1945 [33]. Surgical correction results in resolution of symptoms in most patients with low risk of morbidity and even lower risk of death [3,4,6,7,11,15]. (See 'Outcome' below.)

Indications — Surgical intervention is warranted in most symptomatic patients with vascular rings and slings. The rationale is as follows:

●Symptoms generally do not improve over time without intervention. The exception is patients with nonsevere symptoms caused by innominate artery compression, which often resolve without intervention by age two years. (See 'Surgery for innominate artery compression syndrome' below.)

●There are no other treatment options to ameliorate symptoms. (See 'No role for pharmacologic treatment' below.)

●Surgical outcomes are excellent. (See 'Outcome' below.)

Surgical repair is generally not necessary for asymptomatic patients who are incidentally diagnosed with vascular rings. However, such patients should have regular follow-up, particularly if diagnosed early in life, as symptoms may develop later.

Division for vascular rings — In patients with complete vascular rings, surgical division releases the complete circle formed by the vascular and ligamentous structures around the trachea and esophagus. In rare cases, aberrant retroesophageal structures must be reimplanted to a more usual location.

●Double aortic arch – The preoperative imaging studies are used to identify atretic or stenotic segments of the arches, which become the selected sites for surgical divisions (figure 1). The division point is made in the smaller of the two arches, which is usually the left [3,11]. The approach is generally made via left thoracotomy, which allows excellent exposure of the division point. The ductus or ligamentum also must be divided to release the ring. In cases with a right-sided ductus, the approach is via right thoracotomy [8].

●Right aortic arch with an aberrant left subclavian artery and left ductus – Surgical approach is via a left thoracotomy, and the ductus or ligamentum is identified and divided [8]. If a prominent diverticulum of Kommerell is present in childhood, some centers advocate performing a resection of the diverticulum and reimplanting the aberrant left subclavian artery into the left common carotid artery to remove any potential substrate for recurrent symptoms of tracheal or esophageal compression [11]. In adult patients, the diverticulum of Kommerell may become aneurysmal and resection of the diverticulum may be warranted to reduce the risk of dissection or rupture [34].

Repair is typically performed via open thoracotomy. However, video-assisted thoracoscopic surgical (VATS) techniques and endoscopic robotic-assisted techniques have been adapted to vascular ring ligation and division [35-40]. Patient selection and preoperative imaging are critical for application of these techniques as ligamentous structures are much safer to divide under thoracoscopic conditions compared with systemic arterial vessels with patent lumens. Patient size also may limit the use of endoscopic techniques, with young infants being too small to undergo this procedure.

An open thoracotomy approach is often preferred over VATS since the open approach permits concomitant procedures on other structures (eg, aortopexy, reimplanting the subclavian artery, esophageal mobilization, tracheopexy), if needed. The rationale is that ensuring a complete division at the time of initial surgery, and carefully inspecting to assess for persistent compression of the trachea, may reduce the likelihood of residual symptoms and/or need for reoperation later in life.

The advantage of VATS is that recovery time may be shortened. This was demonstrated in a single-center retrospective study of 47 patients who underwent division of a vascular ring (with VATS in 31 patients and open thoracotomy in 16 patients) [40]. VATS was associated with reduced need for intensive care unit admission, use of chest tubes, chylothorax, and length of hospital stay compared with open repair. Major disadvantages of the VATS approach include the inability to reimplant the subclavian artery and potential for increased bleeding and other complications.

Despite these advantages and disadvantages, most studies comparing the two approaches for vascular ring repair have reported comparable mid- and long-term outcomes between VATS and open thoracotomy [16,39,40]. In one report, VATS was associated with shorter operative duration and hospital length of stay, but complication rates and need for reintervention were comparable between VATS and thoracotomy over median follow-up of 2.1 years [16].

Repair for pulmonary artery sling — In patients with extrinsic tracheal compression without fixed stenosis, the left pulmonary artery is reimplanted from its right-sided origin to the main pulmonary artery, anterior to the trachea. Complete tracheal rings require resection of the affected tracheal segment or tracheoplasty. These procedures require cardiopulmonary bypass [3,41,42].

Surgery for innominate artery compression syndrome — Typically, symptoms resolve without intervention by age two years. However, in patients with severe symptoms (apnea, severe stridor, or recurrent infections), surgical correction is warranted. The usual approach is either surgical sectioning and proximal reimplantation of the innominate artery or an aortopexy procedure, which lifts both the aortic arch and innominate artery anteriorly and to the left by suturing them to the posterior aspect of the sternum [43].

No role for pharmacologic treatment — There is no role for pharmacologic treatment for vascular rings. Although some patients with vascular rings may have received medical therapy including steroids or bronchodilators for respiratory symptoms (stridor or wheezing), there is generally no demonstrated improvement, as the symptoms are caused by mechanical compression rather than bronchospasm.

OUTCOME — Clinical outcome in patients who undergo surgical correction for vascular rings is generally excellent.

●Symptom resolution – Surgical correction results in resolution of symptoms in most patients [3,4,6,7,11,15]. In a case series of 125 patients with complete vascular rings causing respiratory compromise who underwent surgical repair, three-quarters reported improvement in symptoms at the one-month postsurgical follow-up visit [16].

Esophageal symptoms also improve after surgery. In one series, approximately two-thirds of patients with feeding difficulties were symptom free after surgery [6].

In the long-term, most patients have complete resolution of symptoms. In a multi-institution retrospective review of 371 patients with vascular rings undergoing surgical repair, only 7 percent reported residual symptoms at an average follow-up of 4.3 years [15].

Patients with any of the following are more likely to have residual symptoms after surgery [12,44]:

•Tracheobronchomalacia – Respiratory symptoms can persist after surgery for months to years in patients who have tracheobronchomalacia as a consequence of the vascular ring; however, there is usually improvement as the child grows [6,7].

•A prominent diverticulum of Kommerell, if the diverticulum was not surgically resected [11,13]. (See 'Right aortic arch with aberrant left subclavian artery and left-sided ductus arteriosus/ligamentum' above.)

•Underlying genetic syndromes (eg, DiGeorge syndrome, CHARGE syndrome). (See "DiGeorge (22q11.2 deletion) syndrome: Management and prognosis", section on 'Prognosis'.)

•Associated airway and esophageal abnormalities (eg, tracheoesophageal fistula, congenital tracheal stenosis). (See "Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula", section on 'Tracheoesophageal fistula and esophageal atresia' and "Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula", section on 'Congenital tracheal stenosis'.)

●Complications – Potential complications of surgery include recurrent laryngeal nerve injury and chylothorax. In most reports from experienced centers, these occurred in <5 percent of cases [3,4,6,7,11,15].

●Need for reintervention – In the available case series, reoperation rates ranged from 4 to 10 percent [6,7,11-13,15,45]. In one series of 300 patients, 8 percent (n = 26) required reoperation [45]. The most common reason for reoperation was Kommerell diverticulum (n = 18); other indications included circumflex aorta (n = 2), residual scarring (n = 2), and tracheobronchomalacia requiring aortopexy (n = 4).

●Mortality – In the modern era, operative mortality for vascular ring division is very low (ie, <1 percent) [4,6-9,11,12,15]. The few deaths reported in the available case series occurred in patients with other medical issues, including complex congenital heart disease or significant pulmonary disease.

SUMMARY AND RECOMMENDATIONS

●Anatomy – Vascular rings are rare congenital anomalies of aortic arch development that result in compression of the tracheobronchial tree and/or esophagus. Vascular rings can be classified as complete or incomplete depending upon whether the trachea and esophagus are fully encircled. (See 'Anatomy' above.)

•Complete vascular rings – Complete vascular rings are associated with significant symptoms early in life. The two most common forms are (see 'Vascular rings' above):

-Double aortic arch (figure 1) (see 'Double aortic arch' above)

-Right aortic arch and an aberrant left subclavian artery and left-sided ductus arteriosus (figure 2) (see 'Right aortic arch with aberrant left subclavian artery and left-sided ductus arteriosus/ligamentum' above)

Other rare causes of complete vascular rings are listed above. (See 'Other causes' above.)

•Other vascular anomalies – Vascular anomalies that do not completely encircle the trachea and esophagus are often asymptomatic and found incidentally. However, they can be associated with symptoms in some cases. Examples include (see 'Other vascular anomalies' above):

-Pulmonary artery sling (image 1) (see 'Pulmonary artery sling' above)

-Innominate artery compression syndrome (see 'Innominate artery compression syndrome' above)

●Presentation – Patients with complete vascular rings typically present within the first few weeks after birth. Pulmonary artery sling may present immediately after birth with severe respiratory distress. Patients with incomplete vascular rings may be asymptomatic. (See 'Presenting symptoms' above.)

Respiratory symptoms are the most common presenting complaints (eg, stridor, wheezing, cough, recurrent pulmonary infections). Esophageal complaints are also common (eg, dysphagia, feeding difficulty, vomiting).

●Associated anomalies – Children with vascular rings and slings commonly have associated anomalies, particularly cardiac anomalies. Vascular rings can be seen in genetic or malformation syndromes such as DiGeorge, Down, or CHARGE syndromes. (See 'Associated anomalies' above.)

●Evaluation – The clinician must have a high degree of suspicion to diagnosis a vascular ring or sling because they are relatively uncommon causes of respiratory distress. The history and physical examination help to distinguish vascular rings and slings from other diagnostic possibilities. A history of prolonged and recurrent respiratory difficulties and dysphagia is suggestive. (See 'Clinical suspicion and general approach' above.)

Our suggested approach to evaluating infants and children with suspected vascular rings or slings is as follows (see 'Evaluation' above):

•The initial study is a chest radiograph to evaluate for pulmonary pathology and the sidedness of the aortic arch.

•This is followed by both of the following:

-Echocardiography to identify the arch branching pattern and intracardiac anatomy. (See 'Echocardiography' above.)

-Advanced imaging with computed tomography angiography (CTA) or magnetic resonance angiography (MRA) to define the vascular anatomy. (See 'Computed tomography and magnetic resonance angiography' above.)

-Bronchoscopy is reserved for patients exhibiting significant signs/symptoms of airway obstruction. (See 'Bronchoscopy' above.)

●Diagnosis – The postnatal diagnosis of vascular rings and slings is established with CTA or MRA, which provide detailed anatomic information to determine the specific type of vascular anomaly. (See 'Computed tomography and magnetic resonance angiography' above.)

●Surgical correction – Patients with significant symptoms attributable to a vascular ring (eg, respiratory distress, recurrent pulmonary infections, feeding difficulties, poor growth) generally require surgical correction. The surgical approach depends on the specific type of vascular ring. Surgery results in resolution of symptoms in most patients. Surgical repair is generally not necessary for asymptomatic patients who are incidentally diagnosed with vascular rings. (See 'Treatment' above and 'Outcome' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Amy Juraszek, MD, FAAP, FACC, who contributed to earlier versions of this topic review.