Right aortic arch: a radiological rarity but a neurologically remarkable condition

• Published in: Aktuelle Neurologie
• Main Authors: Lezius, F, Gdynia, HJ, Kastrup, A, Riecker, A
• Format: Conference Proceeding
• Language: English
• Published: 11.09.2007
• ISSN: 0302-4350; 1438-9428
• DOI: 10.1055/s-2007-987849

Here we describe a 60-year-old female presenting with recurrent vertigo and dysaesthesias of the left hand. The patient had the impression that symptoms were related to the overhead use of the left arm. Although she had multiple cardiovascular risk factors (hypertension, hyperlipidemia, tobacco use) her medical history was negative for cerebrovascular diseases. Neurological examination revealed no abnormalities. Cerebral MRI was unremarkable, notably no evidence for current or previous stroke. Extracranial colour coded duplex sonography revealed an approximately 50% stenosis of the left external carotid artery and a retrograde flow within the left vertebral artery. Cervical MR-angiography showed right aortic arch with isolation of the left subclavian artery. Therapeutically, a left carotid-subclavian-bypass was performed. Postoperative ultrasound revealed a regular antegrade flow within the left vertebral artery and the patient no longer experienced symptoms of vertebrobasilar insufficiency. Right aortic arch with isolation of the left subclavian artery is a rare congenital anomaly, in which the left subclavian artery no longer communicates with the aorta. It potentially produces hemodynamic alterations with a subsequent subclavian steal phenomenon. To date, a total of 43 patients have been reported, 14 cases occurred in patients over the age of 21 years. In 30 patients, the presence or absence of ischemia was described, but only 5 patients had ischemic symptoms of the left upper limb and further 5 patients of vertebrobasilar insufficiency, respectively. It could be speculated that initially asymptomatic patients with this congenital anomaly may lose their ability to compensate for the steal phenomenon as they age due to a progressive atherosclerosis. Clinical features that should suggest a right aortic arch are diminished pulse or blood pressure in the left upper extremity and/or vertebrobasilar symptoms. The colour coded duplex sonography is the most important screening method when a right aortic arch is assumed.