Pulmonary Artery Sling

What Is Pulmonary Artery Sling?

Pulmonary artery sling, also known as PAS, is a rare condition that occurs when the left pulmonary artery (LPA) arises from the right pulmonary artery (RPA) and then encloses its trachea with the right mainstem bronchus on its way to the left lung surface. To complete the formation of a circulatory ring, a ligamentum arteriosum or ductus arteriosus emerges from the main pulmonary artery (MPA), travels proximally and superiorly in the direction of the left mainstem bronchus, and then joins the descending thoracic aorta afterward.

What Are the Causes?

The clinical signs of patients with a pulmonary artery sling are present, such as:

• Stridor- high-pitched, noisy breathing sound that occurs.

• Respiratory distress in infancy.

• Dysphagia due to esophageal compression.

• Recurrent chest infections.

Patients may present with nonspecific respiratory symptoms such as:

• Chest discomfort.

• Cough.

• Orthopnea- Shortness of breath while lying flat that is eased by sitting or standing.

• Exertional symptoms in late childhood or adulthood.

What Is the Diagnostic Method?

Physical Examination: The physical examination reveals respiratory distress, as evidenced by the following:

• Stridor.

• Dyspnea - Shortness of breath.

• Wheezing - While breathing, make a high-pitched whistling sound.

When the tracheal blockage is present, the infant may have the following symptoms:

• Persistent Tracheal Recoil- Elastic recoil is the lung's natural tendency to shrink after it has been inflated.

• Tachypnea- Abnormally rapid respiratory rate.

When a congenital cardiac abnormality is present, its characteristic outward manifestations can be diagnosed.

Imaging of the Chest: Radiographic examination of the chest shows the lower trachea is twisted to the left and may appear compressed on the right side. Hyperinflation of the right lung was found as a result of impingement and restriction of the right main stem bronchus. Due to a blockage at the level of the left main stem bronchus, the left lung may appear larger. People who have a significant obstruction may get atelectasis in a specific lung or lobe.

The Barium Swallow: The barium swallow would be the preferred diagnostic method. The barium swallow, commonly known as an esophagram, is a diagnostic procedure used to evaluate any abnormalities within the upper gastrointestinal (GI) tract.

Echocardiography: The echocardiography employs sound waves to provide visual representations of the cardiac organ. This widely used diagnostic procedure is capable of visualizing blood circulation within the heart and its valves.

Bronchoscopy: In general, bronchoscopy is not advised for individuals having pulmonary artery slings. If performed, tracheal compression is observed, and tracheomalacia, tracheal stenosis, or either is frequently present. Airway compromise may necessitate tracheal or bronchial repair if it is significant.

Cardiac Angiography and Catheterization: A noninvasive method can typically be used to determine the condition. Before undergoing surgical repair, pulmonary artery angiography could be advised to define anatomic details. This enables the diagnosis of changes in the anatomy of the pulmonary arteries, which may not be visible from noninvasive tests and may affect the surgical strategy. By injecting contrast into the main pulmonary artery and shooting in an oblique view with severe cranial angulation of 60 to 70 degrees, the origin and course of the anomalous left pulmonary artery are manifested.

Imaging Through Radiography: Magnetic resonance imaging (MRI) or magnetic resonance angiography (MRA), computed tomography (CT) scanning, or even a combination of such imaging modalities can aid in identifying the details of the the body and performing a three-dimensional reconstruction of anatomy of the airway.

What Is the Treatment Method?

Medical Treatment: Medical treatment for pulmonary artery sling is supportive until surgery can be performed. Airway blockage and pneumonia may require inpatient care in pulmonary artery sling patients.

• Hypoxemia and breathing difficulties should be treated with supplemental oxygen and endotracheal (ET) intubation. Antibiotics should treat pneumonia.

• Regulate the patient and arrange surgery as promptly as possible. Babies with modest symptoms and no airway obstruction may not need surgery which is rare.

Surgical Intervention: If early surgical surgery is not performed, it is unlikely that symptomatic newborns who have pulmonary artery slings will survive.

• During surgery, the anomalous left pulmonary artery will be divided, and then a reconnecting or restoring of the continuity will be performed to connect it to the main pulmonary artery that is anterior to the trachea.

• It is typically done through a midline sternotomy and cardiopulmonary bypass since it allows for more control. It emphasizes the benefits of cardiopulmonary bypass as a preferred treatment.

• The risk of death varies, and the significant prevalence of bronchial and tracheal anomalies among patients is the single most important factor that determines postoperative mortality.

• The mortality induced by any of these related lesions can potentially be reduced with early and vigorous management.

• Patients may require surgical repair of the obstructed bronchi or trachea at the moment of reimplantation of an atypical left pulmonary artery, whereas if airway stenosis is severe enough, they may not require surgery.

• For instance, sling tracheoplasty is frequently utilized in the treatment of tracheal stenosis that is accompanied by a pulmonary artery sling. After surgery, these symptoms of airway blockage and pneumonia may continue, but they can improve.

• The long-term follow-up of surgical survivors shows that they are free of substantial problems.

Follow-up: After surgery, the patient is required to have close follow-up treatment, including an evaluation for chronic airway obstruction. Even though symptoms in the airways should improve, patients should be monitored constantly, particularly during episodes of upper respiratory infections.

• In a similar vein, when the vascular has been reimplanted, this group of patients should be carefully monitored for the development of left pulmonary artery stenosis.

• Echocardiography (medical imaging technique that utilizes ultrasound waves) is a noninvasive method that can be used to evaluate this, although in some cases, further pulmonary artery angiography (diagnostic procedure used to see and assess the condition of the pulmonary artery, a major blood vessel responsible for carrying deoxygenated blood) may be necessary.

Conclusion

Patients diagnosed with pulmonary slings have an increased risk of death in the first few months of life, and survival without medical intervention is extremely improbable. It is also highly suggested that newborns who have recurring pulmonary signs and symptoms, including a persistent cough, stridor, wheezing, respiratory failure, and lung infections, be checked for the frequent development of a congenital pulmonary artery sling. In addition to this, a pulmonary artery sling should be feared in any newborn who has an opacification of only one side of the lung field. The most successful method of treatment for congenital pulmonary artery syndrome seems to be the early treatment of symptomatic children.