A difference in systolic pressure >10–15 mmHg. If >20, this usually indicates a subclavian artery
occlusion, whose etiology varies based on setting. In an acute situation, it usually suggests aortic dissection
(with aortic regurgitation in cases of more proximal dissection). In more chronic settings, it would instead
indicate a subclavian steal syndrome, wherein blood is “stolen” from the vertebral circulation to feed a
hypoperfused arm. Patients with this condition usually present with vertebrobasilar symptoms, such as vertigo, hemiparesis, ataxia, and visual changes. They can also have a diminished arterial pulse and an ipsilateral bruit over the subclavian artery.
occlusion, whose etiology varies based on setting. In an acute situation, it usually suggests aortic dissection
(with aortic regurgitation in cases of more proximal dissection). In more chronic settings, it would instead
indicate a subclavian steal syndrome, wherein blood is “stolen” from the vertebral circulation to feed a
hypoperfused arm. Patients with this condition usually present with vertebrobasilar symptoms, such as vertigo, hemiparesis, ataxia, and visual changes. They can also have a diminished arterial pulse and an ipsilateral bruit over the subclavian artery.