Right Aortic Arch in Vascular Ring Defects Workup

Updated: Jan 10, 2020
  • Author: Doff B McElhinney, MD; Chief Editor: Howard S Weber, MD, FSCAI  more...
  • Print
Workup

Laboratory Studies

In differentiating vascular rings from upper or lower respiratory infections, a white blood cell (WBC) count and respiratory viral studies may be helpful. However, because patients with double aortic arch are predisposed to respiratory infections, the diagnosis of an infection does not exclude the possibility of a vascular ring with a right aortic arch.

Because of the possible association between right aortic arch and band 22q11 deletion, a karyotype and a fluorescent in situ hybridization (FISH) test for deletions within band 22q11 may be valuable. The diagnosis of band 22q11 deletions allows for targeted evaluation and follow-up for anomalies frequently found in patients with this chromosomal anomaly.

Next:

Electrocardiography

No characteristic electrocardiographic findings are associated with vascular rings, and, except in patients with associated cardiovascular anomalies, electrocardiographic findings usually are normal.

Previous
Next:

Imaging Studies

Chest radiography

In patients with a vascular ring formed by a right aortic arch, chest radiography may or may not reveal the presence of a vascular ring. In the anteroposterior projection, the presence of a right aortic arch may be revealed by the location of the aortic knob and the slight leftward deviation of the lower trachea. On the lateral chest radiograph, posterior indentation of the trachea may be revealed.

Echocardiography

In most cases, the diagnosis of a right aortic arch with aberrant branching can be made reliably using echocardiography with the useful information obtained using suprasternal, high parasternal, and subcostal imaging. However, the presence of a vascular ring cannot always be confirmed and may be missed altogether if the ring is the form with mirror-image branching of the brachiocephalic vessels. Echocardiography is not necessary in the evaluation of patients with a suspected vascular ring if other more valuable imaging studies are available. A right aortic arch with vascular ring can also be identified on prenatal echocardiography.

MRI and CT scanning

Magnetic resonance imaging (MRI) and computed tomography (CT) scanning are the best single imaging studies for the diagnosis and characterization of vascular rings. They provide complete information about the arterial branching pattern, clearly reveal the locations and extent of airway and esophageal obstruction, and can be used to delineate cardiac anatomy. In addition to tomographic images, 3-dimensional reconstruction of the aorta and airways can be a useful tool for preoperative planning.

A study by Chen et al indicated that multislice spiral CT (MSCT) scanning is an effective means of diagnosing double aortic arch and associated complications. In a study of 15 patients with double aortic arch, MSCT scanning identified all 15 cases and also revealed the presence of malformation and tracheobronchial stenosis. The investigators also found that ultrasonography successfully diagnosed only nine of the 15 cases. [12]

Angiography

Although angiography was once the criterion standard for the diagnosis of rings, MRI is both less invasive and diagnostically superior. Angiography may be confusing because of the overlapping projection of the various vascular structures, if appropriate angled angiography is not performed. This problem may be somewhat ameliorated by the use of digital subtraction angiography or countercurrent brachial arteriography, which provides sequential information that can help clarify the aortic branching pattern.

Barium esophagography

Frequently, the diagnosis of a vascular ring is initially made with barium esophagography. In patients with a right aortic arch, a right-sided indentation of the esophagus may be observed on the anteroposterior view, depending on the tightness of the ring. Posterior indentation of the esophagus is nearly always present on the lateral view. Although this test is not necessary to make the diagnosis of a vascular ring, it is often obtained in the preliminary evaluation of patients with symptoms of upper airway and/or esophageal pathology. If a ring is strongly suspected on the basis of findings on chest radiography or echocardiography, barium esophagography is not indicated. Rather, if additional imaging is desired, a more thorough diagnostic study, such as MRI, should be performed.

Previous
Next:

Procedures

Diagnostic procedures are not generally necessary in the evaluation of patients with a right aortic arch.

Histologic tissue examination is not indicated in patients with a right aortic arch.

Bronchoscopy

Bronchoscopy may be obtained in the evaluation of a patient with suspected airway pathology but is not indicated in most patients. Pulsatile compression of the anterior and lateral walls of the trachea can be observed in patients with a vascular ring and a right aortic arch, but the specific type of vascular ring cannot always be determined. Other imaging modalities, especially MRI or CT, permit characterization of the severity and location of tracheal obstruction while offering superior definition of vascular anatomy.

In some cases, depending on surgeon preference, bronchoscopy may be performed in the operating room before and after repair of the vascular ring to determine the efficacy of relief of tracheal compression. This is of particular value in young patients in whom persistent tracheomalacia is a concern.

Cardiac catheterization

Cardiac catheterization is no longer indicated in patients with vascular ring since MRI and CT scanning are diagnostic noninvasive tests with excellent sensitivity and specificity.

Previous