Pulmonary artery sling

Pulmonary sling: morphological findings. Pre- and postoperative course

Pulmonary sling (PS) is a congenital condition in which the left pulmonary artery (LPA) arises from the right pulmonary artery (RPA), forming a sling around the trachea causing tracheal compression. The incidence is not so rare as initially thought. Symptoms of severe airway obstruction often begin in the newborn or young infant. Echo-colour-Doppler may reveal the PS but emphysema can mask the typical findings. Deviation of fluid-filled lungs may be detected prenatally. Chest radiographs show unusual air distribution, deviation of heart and mediastinum and altered tracheobronchial angles. Bronchography and bronchoscopy demonstrate the high incidence of associated tracheal anomalies such as cartilagenous rings and long tracheal stenosis. Anterior oesophageal indentation is not always seen in the oesophogram. Magnetic resonance imaging (MRI) and computed tomography (CT) reveal the PS, but cautious interpretation is necessary because of different levels of the anomalous LPA. PS and associated cardiovascular malformations can be clearly detected by angiography. Associated extrathoracic anomalies are common. Early diagnosis and therapy of PS is mandatory and consists of reimplantation of the LPA into the pulmonary trunk and division of the ligamentum arteriosum. The postoperative course may be cumbersome necessitating bronchological interventions. Tracheal resection may be necessary but restenosis is frequent. A one-stage repair has been proposed in such cases and was successfully done in a few reported cases. Relief of respiratory obstruction is often complete when there are no associated tracheobronchial anomalies. Late postoperative course is favourable but respiratory obstructive attacks may occur with decreasing incidence over time and tracheal growth.

Pulmonary vascular sling: report of seven cases and review of the literature

A total of 130 cases of pulmonary vascular sling, including seven new cases in our collection, were studied. The sex distribution was 60% male and 40% female. The age at presentation was in the first year of life in approximately 90% of cases. Barium-esophagraphy showing anterior indentation was diagnostic in most of the cases. Bronchoscopy and tracheobronchography were useful in detecting associated tracheobronchial anomalies preoperatively. The analysis of 68 autopsied cases revealed associated tracheobronchial anomalies in 40% of the cases. Anomalies of the tracheobronchial tree took three major forms: abnormal distribution of cartilage in the walls of the trachea and major bronchi, intrinsic stenosis, and abnormal branching, the latter being that of bronchus suis. Acquired changes secondary in the sling resulted in compression of the major respiratory pathway by the anomalous left pulmonary artery. Major associated cardiovascular anomalies were present in 30% of the cases. These were represented by ventricular septal defect, atrial septal defect, patent ductus arteriosus, tetralogy of Fallot, common ventricle, and coarctation of the aorta.

The diagnosis of airway obstruction in children

Airway obstruction in children has many causes. Although vascular rings may have early onset of symptoms there was considerable delay in establishing the correct diagnosis. Barium swallow is diagnostic. Other tests, such as angiocardiography, bronchoscopy, bronchography, and lung scan are usually unnecessary. Pulmonary sling is a less common cause of vascular obstruction. Barium swallow showing anterior indentation at the level of the pulmonary hilum is diagnostic. Cysts and tumors are other causes of severe airway obstruction. The diagnostic and operative problems in three patients are discussed as examples. It is concluded that barium swallow is the most important single investigation in the evaluation of airway obstruction.

Aberrant left pulmonary artery. Review of surgical results and report of a successfully treated case

Aberrant left pulmonary artery is a rare anomaly which can cause severe respiratory distress by compressing the distal trachea. The most reliable diagnostic measures are barium swallow, which in most cases shows an anterior indentation of the oesophagus, and a pulmonary arteriogram to provide a conclusive diagnosis. Tomography of the trachea and the main bronchi should be performed, in order to detect possible additional malformations in the airways. In severely symptomatic cases, surgical correction should be done before a life-threatening situation has developed. The correction is best performed through a left thoracotomy, with transposition of the left pulmonary artery and end-to-side anastomosis to the main pulmonary artery. The postoperative course may be difficult, and the patient may require respirator support for two to three weeks. Early surgical revision must be considered if symptoms persist, if additional stenosis is demonstrated, or if malformations such as complete tracheal rings are observed in the area of compression at the time of the vascular correction.

Pulmonary artery sling

Pulmonary artery "sling" indicates the vascular anomaly wherein the left pulmonary artery arises from the right pulmonary artery and traverses between the esophagus and trachea to enter the left lung. Respiratory symptoms may result from compression of the trachea and right mainstem bronchus by the anomalous vessel as well as by associated tracheobronchial defects. Six cases are described. The distinctive radiologic features include anterior indentation of the barium esophagogram and a characteristic pulmonary angiogram. Surgery is the usual recommended treatment for life-threatening airway obstruction, but results are often poor. In patients with less severe symptoms the physician's approach may be modified by the presence of associated intracardiac defects and intrinsic airway disease.

Early and late results of surgical correction of pulmonary artery sling

Since 1976, we have operated on 4 children with pulmonary vascular sling. They were 5, 12, 19, and 54 months old. All patients were seen initially with severe stridor. Diagnosis was made by barium swallow in all 4. Each child was operated on through a left thoracotomy; the left pulmonary artery was dissected deep between the trachea and esophagus. Systemic heparinization and microsurgical techniques were used. All patients improved after operation. Radioisotope pulmonary ventilation/perfusion scans were performed 9, 9, 14, and 21 months after operation. Decreased ventilation was noted in the right upper lobe of one scan; the other three ventilation scans were normal. Perfusion scans showed good patency of both pulmonary arteries in all 4 patients. It is concluded that pulmonary vascular slings should be treated surgically as soon as diagnosed. Delayed operation can lead to severe tracheomalacia, as demonstrated in our 54-month-old patient.