Pulmonary Artery Sling Workup
- Author: Stuart Berger, MD; Chief Editor: Steven R Neish, MD, SM more...
Imaging Studies
In pulmonary artery sling, the following imaging studies may be indicated:
- Chest radiography: The lower trachea is deviated to the left and may appear compressed on its right side. Hyperinflation of the right lung may be seen because of impingement on and compression of the right main stem bronchus. The left lung also may appear hyperinflated because of obstruction at the level of the carina and the left main stem bronchus. In patients with severe obstruction, atelectasis of a single lung or single lobe may be observed. The lateral view may reveal a density anterior to the esophagus and posterior to the trachea just above the carina. This is the left pulmonary artery viewed on end.
- Barium swallow: The barium swallow is the diagnostic procedure of choice. An anterior indentation of the esophagus on the lateral projection is diagnostic of pulmonary artery sling. The esophagus is usually displaced to the right in the frontal projection and demonstrates an oblique impression immediately posterior to the carina.
- Echocardiography: In the usual coronal-plane suprasternal-notch images, absence of normal bifurcation of the main pulmonary artery into right and left pulmonary arteries is visible. The left pulmonary artery appears to be absent. However, examination of the right pulmonary artery reveals the left pulmonary artery arising from its posterior surface. The left pulmonary artery can be followed posterior to the trachea and anterior to the esophagus. It passes anterior to the descending aorta and enters the hilum of the left lung. Echocardiography also reveals any associated congenital heart defects.
Bronchoscopy is generally not recommended. If performed, tracheal compression is noted, and accompanying tracheomalacia, tracheal stenosis, or both is common.[2] Some recommend bronchoscopic evaluation of selected surgical candidates because surgical reconstruction of the trachea or bronchi may be necessary if the airway compromise is severe.
Currently, MRI or magnetic resonance angiography, CT scanning, or a combination can be helpful in delineating the details of the anatomy,[3] as well as in 3-dimensional reconstruction of the anatomy of the sling as it relates to the airway anatomy.
Procedures
- Cardiac catheterization and angiography: Diagnosis can usually be noninvasively established. Pulmonary artery angiography may be advisable to delineate anatomic details prior to surgical correction. This permits diagnosis of variations in right and left pulmonary artery anatomy that may not be apparent from noninvasive studies and that can alter the surgical approach. Origin and course of the anomalous left pulmonary artery is best revealed by contrast injection into the main pulmonary artery filming in an oblique view with steep cranial angulation of 60-70 º.
Sade RM, Rosenthal A, Fellows K, et al. Pulmonary artery sling. J Thorac Cardiovasc Surg. Mar 1975;69(3):333-46. [Medline].
Loukanov T, Sebening C, Springer W, et al. Simultaneous management of congenital tracheal stenosis and cardiac anomalies in infants. J Thorac Cardiovasc Surg. Dec 2005;130(6):1537-41. [Medline].
Newman B, Cho YA. Left Pulmonary Artery Sling-Anatomy and Imaging. Semin Ultrasound CT MR. Apr 2010;31(2):158-170. [Medline].
Potts W, Holinger P. Anomalous left pulmonary artery causing obstruction to the right main stem bronchus. JAMA. 1954;155:1409.
Backer CL, Russell HM, Kaushal S, Rastatter JC, Rigsby CK, Holinger LD. Pulmonary artery sling: Current results with cardiopulmonary bypass. J Thorac Cardiovasc Surg. Jan 2012;143(1):144-51. [Medline].
Freedom R, Culham J. The Angiography of Congenital Heart Disease. 1998.
Grover FL, Norton JB Jr, Webb GE, et al. Pulmonary sling. Case report and collective review. J Thorac Cardiovasc Surg. Feb 1975;69(2):295-300. [Medline].
Morrow R, Huhta J. Aortic arch and pulmonary artery anomalies. In: The Science and Practice of Pediatric Cardiology. 1990:1444-7.
Niwayama G. Unusual vascular ring formed by the anomalous left pulmonary artery, with tracheal compression. Am Heart J. Mar 1960;59:454-61. [Medline].
Semple MG, Bricker L, Shaw BN, Pilling DW. Left pulmonary artery sling presenting as unilateral echogenic lung on 20-week detailed antenatal ultrasound examination. Pediatr Radiol. Aug 2003;33(8):567-9. [Medline].
Tesler UF, Balsara RH, Niguidula FN. Aberrant left pulmonary artery (vascular sling): report of five cases. Chest. Oct 1974;66(4):402-7. [Medline].

