The aberrant subclavian artery.

Abstract

During the last 6 years we have retrospectively identified 32 patients with aberrant subclavian arteries and related vascular rings. Twenty-seven patients had a left-sided aortic arch with an aberrant right suhclavian artery (ARSA). whereas four had a right-sided aortic arch with an aberrant left subclavian artery. All these patients were asymptoniatic. Aneurysm of an ARSA was seen in one patient. One patient had a double aortic arch and dysphagia. Twenty-one of the subjects were female. and I I were niale. They ranged in age from 5 months to 75 years old (mean age. 54 years old). Barium esophagography was performed in I 3 patients. CT in 20. MR imaging in two. and conventional angiography in three. Discussion The ARSA was first described on necropsy by Hunauld in 1735. In 1787, David Bayford, before the Medical Society of London. used the term “dysphagia lusoria,” or “difficulty in swallowing due to a quirk of nature,” in describing symptoms related to this anomaly. The radiologic findings were first described in 1936 by Kommerell. and surgical management of the problem was discussed by Gross in 1946(1]. The ARSA is the most common of the intrathoracic major arterial anomalies, with an incidence of 0.4-2%. In this anomaly. the ARSA arises as the last great vessel of the aortic arch. The anomaly occurs as a result of interruption between the right common carotid artery and the ARSA in the developing double aortic arch. Normal embryonic development of the aortic arch and great vessels begins as six paired ventral and dorsal arches [I]. Certain segments disappear, and others persist during development of the fetus. The left fourth arch forms the aortic arch. The right fourth arch contributes to the formation ofthe right subclavian artery. as does the seventh intersegmental artery. In the ARSA, the right fourth arch and proximal right dorsal aorta involute. and the right seventh intersegmental artery develops from a persistent dorsal aorta [ I I. An aortic diverticulum may be present at the origin of this vessel. representing the remnant of the distal right aortic arch. The ARSA arises from the dorsal margin of the aorta. It then passes behind the esophagus (Figs. 1-5) in almost all cases; indeed, passage of the ARSA in front of the esophagus or trachea occurs rarely if ever [2[. An aberrant left subclavian artery arising from a right aortic arch is far less common. occurring in one in 1000 people. Most patients with ARSA are asymptomatic. and the anomaly is found incidentally. either by radiography or endoscopy. Rarely. this malformation has been suspected as the cause of dysphagia. Pediatric patients may present with respiratory compromise due to tracheal compression. In adults, the trachea is more resistant to compression. An aneurysmal aberrant subclavian artery may present as a superior mediastinal mass. On barium esophagography. the ARSA consistently produces a characteristic oblique fron-