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Editorial commentary on pulmonary artery sling with tracheal stenosis

Chirurgie Cardiaque Pédiatrique, Hôpital Necker – Enfants Malades, 149 rue de Sèvres, 75015 Paris, France

^* Corresponding author: Tel.: +33-1-4438 1867; fax: +33-1-4438 1911. pascal.vouhe{at}nck.aphp.fr

In the current issue of the Multimedia Manual of Cardiothoracic Surgery, Doctor Hraska and his co-workers describe in detail and illustrate beautifully the procedure for repairing pulmonary artery sling with associated localized tracheal stenosis [1]. A few comments may be useful to provide a more complete overview of this rare congenital anomaly.

Pulmonary artery sling is a malformation in which the left pulmonary artery arises from the right pulmonary artery and then passes leftward between the trachea and the oesophagus. Children with this malformation come to medical attention because of respiratory difficulties due to tracheo-bronchial obstruction; however, tracheal obstruction may be secondary either to simple compression without underlying tracheal lesion, or to associated congenital tracheal stenosis. The management and prognosis depend mainly upon the presence of associated tracheal lesions and, occasionally, associated cardiac defects.

Approximately half of the patients with pulmonary artery sling have a morphologically normal tracheo-bronchial tree. Respiratory symptoms are related to external compression by the anomalous left pulmonary artery. The affected area involves the origin of the right main bronchus and the trachea just above the carina. Complete relief of the compression (and related symptoms) can usually be obtained by simple division and reimplantation of the anomalous left pulmonary artery (with concomitant division of the ligamentum arteriosum or patent ductus arteriosus). The operation may be performed either through a left thoracotomy without cardiopulmonary bypass (CPB), or through a median sternotomy using CPB [2]. The latter approach is indicated in patients with associated cardiac defects (which need concomitant repair) and in infants (in whom partial occlusion of the pulmonary trunk for reimplantation of the left pulmonary artery may be difficult or badly tolerated). Repair through a left thoracotomy and without CPB remains indicated in older children.

The other half of patients with pulmonary artery sling have associated congenital tracheal stenosis, secondary to the presence of complete cartilage rings (ring-sling complex) [3]. The tracheal lesion may be localized to the region where the sling passes around the trachea, but often it extends for the entire length of the trachea; the proximal main bronchi may be involved as well. In the affected area, the pars membranacea is absent and the lumen is usually severely narrowed, although this is not necessarily the case. In patients with ring-sling complex, any obstructive tracheal lesion must be repaired in association with relocation of the anomalous left pulmonary artery. When the tracheal stenosis is localized (up to 30–40% of the entire tracheal length), resection of the stenosis with end-to-end anastomosis is indicated (the procedure extensively described in the current issue). When there is diffuse tracheal stenosis, the surgical problem is more difficult. Relocation of the anomalous pulmonary artery and simultaneous extended tracheoplasty of some type are indicated. Several procedures have been used, including slide tracheoplasty or patch tracheoplasty using various materials (fresh autologous pericardium, free rib cartilage graft or free tracheal autograft patch). The optimal solution remains a matter of controversy.

The above considerations emphasize the importance of careful preoperative evaluation. The vascular anomaly should be suspected in any child with respiratory symptoms and can be readily diagnosed using echo-Doppler evaluation. CT scan with 3D reconstruction has become the key tool to (1) confirm the vascular anomaly, (2) identify the mechanism of tracheal obstruction (external compression or tracheal lesion with complete cartilage rings), (3) define the extent and severity of tracheal stenosis if present, (4) diagnose associated anomalies (particularly bronchus suis). Preoperative tracheo-bronchial endoscopy may be dangerous in patients with severe stenosis but remains mandatory during operation to delineate the tracheal lesion, guide the surgical repair and evaluate the immediate result.

	References

Top References

 

1. Hraka V, Photiadis J, Haun C, Schindler E, Schneider M, Murin P, Asfour A. Pulmonary artery sling with tracheal stenosis.Multimedia Man Cardiothorac Surg doi: 10.1510/mmcts.2008.003343.[Abstract/Free Full Text]
2. Kouchoukos N, Blackstone E, Doty D, Hanley F, Karp R. Cardiac Surgery, 3rd Edition. Churchill Livingstone, 2003:1426–1437.
3. Berdon WE, Baker DH, Wung JT, Chrispin A, Kozlowski K, de Silva M, Bales P, Alford B. Complete cartilage-ring tracheal stenosis associated with anomalous left pulmonary artery: the ring-sling complex. Radiology 1984;152:57–64.[Abstract/Free Full Text]

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Pulmonary artery sling with tracheal stenosis

Viktor Hraska, Joachim Photiadis, Christoph Haun, Ehrenfried Schindler, Martin Schneider, Peter Murin, and Boulos Asfour
MMCTS 2009 2009: 3343. [Abstract] [Full Text] [PDF]