Subclavian Steal Syndrome

This patient is an elderly woman with recurrent 'spells' at home. She recently lost consciousness while attempting to hang curtains. She has smoked for 60 years. There is no history of heart disease and she has never experienced angina.

Defined as a syndrome involving stenosis or obstruction of the subclavian artery proximal to the origin of the vertebral artery, Subclavian steal syndrome is characterized by 'Flow Reversal' in the ipsilateral Vertebral Artery and decreased cerebral perfusion. In essence, blood flow is 'stolen' by the ipsilateral vertebral artery from the contralateral side. This may then result in transient neurologic symptoms either continuously or in relationship to arm exercises. Peak incidence is in the 40-60 year old age group with males outnumbering females 2-3 to one. When subclavian disease is seen in patients younger than 30, Arteritis (Takayasu) should be suspected. Causes of subclavian artery disease include atherosclerosis, Takayasu's Arteritis, Giant cell Arteritis, tumor burden, trauma, and scar tissue among others.

In most cases, subclavian stenosis is an incidental finding as many patients are completely asymptomatic.

Diagnosis is suggested by clinical symptoms and a blood pressure difference between the upper extremities. Doppler ultrasound evaluation can reliably diagnose the problem. Treatment consists of surgical or percutaneous revascularization. The case shown here was treated successfully using contemporary catheter techniques combined with stent deployment.

One classification of Subclavian Steal is based upon the vascular bed from which blood is stolen. Four types have been described by Vollmar: Vertebro-Vertebral, Carotid-Basilar, External Carotid-Vertebral, and Carotid-Subclavian.

Symptoms are frequently attributed to the vertebrobasilar system and include dizziness, lightheadedness, vertigo, and drop attacks. Stroke probably occurs infrequently. Some patients experience numbness/parasthesias or frank arm claudication with movement of the affected upper extremity. Arm pain may also occur at rest but hand ischemia occurs rarely. Symptomatic patients frequently have other extra-cranial vascular disease. Patients frequently have traditional vascular risk factors of hypertension, smoking, diabetes, and hyperlipidemia.

Since the risk of stroke is low, treatment is reserved for patients with debilitating symptoms. In patients with prior bypass surgery for ischemic heart disease, subclavian stenosis may lead to decreased anterior wall perfusion and angina if blood flow into a patent internal mammary artery is compromised by subclavian stenosis. In this setting, revascularization of the subclavian artery can eliminate angina.