Presentation
History of severe hypertension. He presented with sudden onset of chest pain, radiating to his right arm. Upon arrival at the emergency room, his blood pressure was mesured at 220/150 mmHg (no significant difference between the arms).
Patient Data
There is a dissection of the aorta, beginning just distal of the aortic arch vessels. The dissection spreads in a retrograde fashion to an aberrant right subclavian artery (arteria lusoria) that passes dorsal to the esophagus and the trachea. The dissection of this vessel continues all the way to the subclavian and axillary arteries, as far as they can be traced. There is no involvement of the other aortic arch branches, nor of the ascending aorta.
Case Discussion
The aberrant right subclavian artery (arteria lusoria) is not uncommon; the prevalence of this vascular variant is appreciated to be in the range of 0.5-2%.
When a dissection occurs distal to the aortic arch vessels, it is usually propagated distally to the descending and eventually abdominal aorta, inluding branching vessels. It might however also spread proximally, which in a patient with normal vascular anatomy in turn would involve the left subclavian artery, the left common carotid artery and the innominate artery. In this patient however, the first (=most distal) aortic arch vessel to be involved in the dissection was the aberrant right subclavian artery, with no involvement of the other aortic arch vessels. This explains the somewhat unusual clinical presentation with chest pain radiating to the right but not the left arm.
This particular case (as well as other cases of dissections beginning distal to the arch vessels but with retrograde involvement of the same vessels) poses a challenge of classification. It has been proposed that such pattern be classified as a type B dissection with aortic arch involvement 1.