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Year : 2008  |  Volume : 18  |  Issue : 2  |  Page : 124-125
Case report: Multi-detector CT of left pulmonary artery sling


1 Department of Cardiac Radiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi - 110 029, India
2 Department of Cardiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi - 110 029, India

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How to cite this article:
Singh CK, Sharma S, Kothari S S, Jagia P. Case report: Multi-detector CT of left pulmonary artery sling. Indian J Radiol Imaging 2008;18:124-5

How to cite this URL:
Singh CK, Sharma S, Kothari S S, Jagia P. Case report: Multi-detector CT of left pulmonary artery sling. Indian J Radiol Imaging [serial online] 2008 [cited 2019 Oct 18];18:124-5. Available from: http://www.ijri.org/text.asp?2008/18/2/124/40292
Left pulmonary artery sling (LPAS) is a rare vascular anomaly in which the left pulmonary artery (LPA) arises from the right pulmonary artery (RPA) and enters the left hilum after passing between the trachea and the esophagus; it can cause respiratory distress. This case demonstrates the role of multi-detector CT (MDCT) in the diagnosis of LPAS and associated cardiovascular and tracheobronchial anomalies.


   Case Report Top


A 4-month-old male infant with Down's syndrome and atrial septal defect presented with respiratory distress and recurrent pneumonia. A chest radiograph revealed reduced aeration of the left lung as compared to the right. The echocardiogram showed poor visualization of the pulmonary confluence and the proximal LPA. CT scan was performed on a 16-slice CT scanner (Sensation-16, Siemens, Germany). Iodinated non-ionic contrast, 2 ml/kg body weight, was injected using a pressure injector. Axial source and volume-rendered images revealed the LPA arising from the proximal RPA and coursing to the left hilum, between the trachea and the esophagus [Figure - 1] A, B. Mildly reduced lung volume was also noted on the left. An associated aberrant right subclavian artery, coursing behind the esophagus was also detected [Figure - 1]C.

A volume-rendered image, obtained for the tracheobronchial anatomy [Figure - 2], revealed long-segment stenosis of the left main bronchus, besides showing the vascular indentations by the LPA on the trachea and the esophagus, as well as the impression of the aberrant subclavian artery on the esophagus.

The child was operated upon successfully, with reimplantation of the LPA into the main pulmonary artery and bronchoplasty.


   Discussion Top


The first case of pulmonary artery sling was reported by Glaevecke and Doehle in 1897. [1] Embryologically, it is thought to be due to involution of the proximal left sixth arch. [2] The anomalous LPA is formed by a collateral vessel from the RPA in response to the lack of arterial supply to the left side, thus linking the primitive circulations. [3] In the area where this anomalous LPA passes behind the bronchus there is likely to be bronchial compression, resulting in functional stenosis. Chen et al . [4] believe that tracheal stenosis and LPAS are both primary conditions that occur together as part of the developmental anomaly. They also espouse the "space availability concept" wherein the development of the associated patent ductus arteriosus and persistent left superior vena cava are due to the increased space on the left, where the normal LPA would otherwise have been placed.

Fifty percent of affected infants are symptomatic at birth, while by one month of age, two-thirds of infants have clinical symptoms. [5] The commonest clinical presentations include recurrent respiratory distress, stridor, and wheezing. The mortality rate is up to 90% in medically managed cases. [6] Even after surgical correction, LPAS can be fatal in up to 50% of cases. [5]

The prognosis is affected by the presence of associated tracheobronchial tree anomalies, especially a long tracheobronchial stenosis. [7] The tracheobronchial anomalies may include a bronchus arising directly from the trachea to supply a segment of the right upper lobe (bronchus suis), hypoplasia of the distal trachea, incomplete cartilaginous tracheal ring, and left main bronchial stenosis. [3] Cardiovascular anomalies consist of atrial septal defect, patent ductus arteriosus, ventricular septal defect with pulmonary stenosis, tetralogy of Fallot, aortic arch anomalies, and persistent left superior vena cava. [4],[5] Therefore, optimal preoperative imaging of the tracheobronchial and cardiovascular anatomy is essential for planning surgical management. [8],[9],[10]

MDCT helps avoid invasive investigations such as bronchoscopy and pulmonary artery angiography. [11] The associated cardiovascular and tracheobronchial anomalies too, are easily detected. In this case, CT images were considered adequate for the diagnosis and assessment of the anatomical relationship of the tracheobronchial tree, prior to surgical management.

 
   References Top

1.Glaevecke H, Doehle W. Uber eine selten angeborene Anomalie der Pulmonalarteren. Munch Med Wochenschr 1897;44:950-3.  Back to cited text no. 1    
2.Arey JB. Malformations of the aorta and aortic arches. In : Arey JB, editor. Cardiovascular pathology in infants and children. WB Saunders Company: 1984. p. 242-4  Back to cited text no. 2    
3.Jue KL, Raghib G, Amplatz K, Adams P Jr, Edwards JE. Anomalous origin of the left pulmonary artery from the right pulmonary artery: Report of 2 cases and review of the literature. AJR Am J Roentgenol 1965;95:598-610.  Back to cited text no. 3    
4.Chen SJ, Lee WJ, Lin MT, Wang JK, Chang CI, Chiu IS, et al . Left pulmonary artery sling complex: Computed tomography and ­hypothesis of embryogenesis. Ann Thoracic Surg 2007;84:1645-50.  Back to cited text no. 4    
5.Sade RM, Rosenthal A, Fellows K, Castaneda AR. Pulmonary artery sling. J Thorac Cardiovasc Surg 1975;69:333-46.  Back to cited text no. 5  [PUBMED]  
6.Gikonyo BM, Jue KL, Edwards JE. Pulmonary vascular sling: ­Report of seven cases and review of the literature. Pediatr Cardiol 1989;10:81-9.  Back to cited text no. 6  [PUBMED]  
7.Backer CL, Idriss FS, Holinger LD, Mavroudis C: Pulmonary artery sling (results of surgical repair in infancy). J Thorac Cardiovasc Surg 1992;103:683-91.  Back to cited text no. 7    
8.Lee KH, Yoon CS, Choe KO, Kim MJ, Lee HM, Yoon HK, et al . Use of imaging for assessing anatomical relationships of tracheobronchial anomalies associated with left pulmonary artery sling. Pediatr Radiol 2001;31:269-78.  Back to cited text no. 8  [PUBMED]  [FULLTEXT]
9.King HA, Walker D. Pulmonary artery sling. Thorax 1984;39:462-5.  Back to cited text no. 9  [PUBMED]  
10.Stone DN, Bein ME, Garris JB. Anomalous left pulmonary artery: Two new adult cases. AJR Am J Roentgenol 1980;135:1259-63.  Back to cited text no. 10  [PUBMED]  [FULLTEXT]
11.Hedge AN, Halankar JA, Desai SB. Pulmonary artery sling: A case report. Indian J Radiol Imaging 2004;14:405-7.  Back to cited text no. 11    

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Correspondence Address:
Priya Jagia
Department of Cardiac Radiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi - 110 029
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0971-3026.40292

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