Vascular Compression Syndromes

Abstract

Vascular compression syndromes consist of vascular rings, pulmonary artery slings, and innominate artery compression syndrome. Vascular rings cause the majority of vascular compression syndromes. A double aortic arch and a right aortic arch with an aberrant left subclavian artery constitute approximately 85–95% of all thoracic vascular compression syndromes. There are no demographic predispositions to vascular compression syndromes. These anomalies occur equally in both males and females. Complete vascular rings encircle the trachea and esophagus causing compressive symptoms. Younger children tend to present with respiratory symptoms such as noisy breathing, stridor, cyanosis, apnea, respiratory distress, or a brassy cough. Patients might also have a history of reactive airway disease or recurrent pneumonias. It is not uncommon for children with a complete vascular ring to have some feeding difficulty, however formula and breast milk usually pass easily through the compressed esophagus. It is more common for older children to have symptoms of dysphagia and difficulty feeding. Patients with complete rings tend to present earlier and have more severe symptoms.

Appendices

Summary Points

Vascular compression syndromes should be considered for children with noisy breathing, recurrent pneumonias and older children with dysphagia.

Work-up consists of a plain chest radiograph followed by an echocardiogram.

An esophagram can be confirmatory, if echocardiography is not available.

A magnetic resonance arteriogram or computed tomographic arteriogram is very helpful to define the anatomy for surgical planning.

Bronchoscopy is usually not necessary; however, the diagnosis is sometimes made during bronchoscopy for an airway work-up.

Consider thoracoscopic division to divide the ligamentum arteriosum or to divide a narrow or atretic segment of a double aortic arch.

Editor’s Comment

In many tertiary care pediatric centers, pediatric cardiac surgeons are responsible for the care of patients with a vascular compression syndrome. Nevertheless, pediatric surgeons need to be aware of the signs and symptoms of these uncommon anomalies and should be familiar with the basic anatomy and principles of management. It is not uncommon to encounter a vascular anomaly during a thoracotomy or thoracoscopy being performed for esophageal atresia or other mediastinal lesion, in which case it is important to know what to do and, perhaps more importantly, what not to do. Such a finding usually prompts an immediate review of available imaging to see if something was missed on the initial reading. The next step is to carefully dissect and define all structures, including those on the opposite side of the ­mediastinum, being very careful not to injure important adjacent structures. No vessel should be divided unless it is clear that a true ring exists and that there is brisk flow in the descending aorta after test occlusion of the vessel in question.

For certain vascular anomalies, the thoracoscopic approach is safe in experienced hands. Vessels can be ligated with a variety of techniques and most surgeons prefer to use at least two for added safety. In small children, most vessels can be clipped and then divided with bipolar electrocautery or the harmonic scalpel. Other options include simple suture ligation and oversewing the end with a running permanent monofilament suture. Stapling devices would probably work well but there is rarely enough space to manipulate the device and fire it properly without fear of inadvertently ­incorporating an important adjacent structure or nerve.

Bleeding is the most feared complication as these are large, high-pressure, high-flow vessels that have a tendency to retract and become extremely difficult to control. Even when the bleeding is stopped, much to the relief of all present, the risk of injury to other structures (recurrent laryngeal nerve) is significant. A contingency plan must be prepared in advance, especially if the procedure is being performed thoracoscopically, with the ability to perform a rapid thoracotomy at a moment’s notice. Proximal and distal control of all vessels can be difficult and time-consuming but it is time well invested.

Finally, chylothorax is a particularly distressing complication and one that is often frustrating to manage. It is best prevented by using meticulous technique and staying close to all vessels being dissected. At the conclusion of the operation, one should take a moment to observe the operative field closely for signs of a chyle leak and place sutures to repair a leak if one is found. Some have suggested that application of a commercially available fibrin sealant works well to help small chyle leaks to seal. If a chylothorax occurs, management includes establishing drainage with a chest tube, initial bowel rest, and a great deal of patience. If the leak persists after 3 or 4 weeks, operative management should be considered, which can be difficult given that this entails a redo operation in the chest.

Differential Diagnosis

Tracheomalacia

Laryngomalacia

Complete tracheal ring

GERD

Diagnostic Studies

Plain chest radiograph, consider confirmatory eso­phagram

Echocardiography

CT-angiogram

MR-angiogram

Parental Preparation

Possible conversion to thoracotomy for thoracoscopic procedures

Possible catastrophic breathing

Symptoms might take time to resolve, mostly due to persistent tracheomalacia

Preoperative Preparation

Two large-bore IVs

Type and crossmatch

Arterial line monitoring

Pulse-oximeter on the left upper extremity and one lower extremity

Thoracotomy tray open for thoracoscopic pro­cedures

Informed consent

Technical Points

Most vascular compression anomalies are approached from the left side.

All vascular structures should be carefully dissected and visualized before any structure is ligated and divided.

The vagus, recurrent laryngeal, and phrenic nerves should be carefully identified and protected throughout the procedure.

One must be prepared for the possibility of catastrophic bleeding and have a plan for dealing with it should it occur.

The best treatment for hemorrhage is prevention: proximal and distal control of vessels, ability to convert rapidly to open thoracotomy, all instrumentation available at a moment’s notice.

Thoracoscopic plastic interlocking clips can be used to control vascular structures that are to be divided.

Chest tubes are optional.