What are the symptoms and treatment options for subclavian steal syndrome?

Subclavian Steal Syndrome: Symptoms and Treatment

Subclavian steal syndrome should not be treated with revascularization unless the patient is symptomatic or the internal mammary artery is required for myocardial revascularization. 1

Clinical Presentation and Symptoms

Subclavian steal syndrome occurs when proximal subclavian artery stenosis or occlusion leads to retrograde blood flow in the vertebral artery. Symptoms include:

Vertebrobasilar Insufficiency Symptoms

• Dizziness and lightheadedness
• Syncope (fainting)
• Vertigo
• Ataxia (poor coordination)
• Diplopia (double vision)
• Visual disturbances
• Motor deficits
• Dysphasia and dysarthria
• Facial sensory deficits 1

Upper Extremity Symptoms

• Arm or hand claudication (fatigue and pain with exertion)
• Paresthesia (numbness/tingling)
• Rest pain in severe cases 1

These symptoms typically worsen with exercise of the affected arm, which increases demand for blood flow and amplifies the steal phenomenon 1.

Diagnostic Approach

1. Physical Examination:

   • Check for asymmetry between left and right arm blood pressure (difference >10-15 mmHg is suspicious) 1
   • Listen for periclavicular or infraclavicular bruit 1

2. Imaging:

   • Duplex ultrasonography: Can identify reversal of flow in vertebral artery 1
   • CTA or MRA of the aortic arch: To confirm subclavian artery stenosis 1
   • Hyperemia testing and transcranial Doppler when available 1

Treatment Options

Medical Management

• For asymptomatic patients:
  • No specific intervention needed
  • Secondary prevention strategies for atherosclerosis 1
  • Antiplatelet therapy (aspirin 75-325 mg daily) 2
  • Aggressive cardiovascular risk factor modification 1, 2

Revascularization

Revascularization is indicated for:

1. Symptomatic patients with TIA/stroke or severe ischemia 1
2. Patients with coronary subclavian steal syndrome 1
3. Patients requiring CABG using the ipsilateral internal mammary artery 1
4. Cases of ipsilateral hemodialysis arteriovenous access dysfunction 1

Revascularization Options:

1. Endovascular Approaches:

   • Angioplasty with or without stenting
   • Lower complication rates than surgery
   • Primary patency rates: 93% at 1 year, 70% at 5 years 2

2. Surgical Options:

   • Carotid-subclavian bypass
   • Subclavian-carotid arterial transposition
   • Carotid-axillary or axilloaxillary bypass
   • Excellent long-term patency (96% at 5 years) 1, 2

The choice between endovascular and surgical approaches should be discussed case by case by a vascular team, though endovascular revascularization may be preferred due to lower complication rates despite similar long-term outcomes 1.

Important Considerations

• Most cases of subclavian steal are asymptomatic (subclavian steal phenomenon) and do not require intervention 3, 4
• Routine revascularization in asymptomatic patients is not recommended 1
• Post-revascularization, patients should be monitored for restenosis and recurrent symptoms 2
• Long-term antiplatelet therapy is recommended after revascularization 2

The management of subclavian steal syndrome should focus on symptom relief and prevention of vertebrobasilar insufficiency, with intervention reserved for those with significant symptoms or specific indications for revascularization.