Aortic Arch Anomalies, Tracheal Compression and Stenosis

Abstract

Aortic arch anomalies represent a group of diverse congenital malformations. Classification of aortic arch anomalies is based on the various possible sites of involution of the right or left fourth aortic arches. Many cases are asymptomatic and therefore not diagnosed. These anomalies represent approximately 30% of all cases of congenital heart disease. They can present clinically in 3 different ways. These anomalies can present either early in life with tracheal or esophageal compression or be part of a part of a broader context of congenital heart disease. They can also be established on routine radiological examination in an asymptomatic child or adult. Multiple imaging techniques (CXR, barium swallow, CT-scan, angiography, echocardiography and bronchoscopy) can help detect these anomalies. However MRI provides a complete and precise anatomical assessment of these anomalies and their consequences on the tracheobronchial tree and oesophagus. Schematically, four types of anomalies can be encountered. The vessels can be in an abnormal position (double aortic arch, anomalous left pulmonary artery, etc.) or a malformation of the cardiac chambers can induce the enlargement of the aorta or pulmonary artery, or a vessel can be in an abnormal position. All these can induce a direct compression of the trachea or bronchial tree. Another possibility is intrinsic tracheal anomalies and compression by a vessel in a normal position. The most frequent form of vascular ring is represented by the double aortic arch and is due to persistence of both the left and right aortic arches. The other aortic arch anomalies are the left aortic arch with aberrant right subclavian artery or right aortic arch with aberrant left subclavian artery, right aortic arch and anomalies of the sixth aortic arch.