What is the management of Subclavian Steal Syndrome?

Management of Subclavian Steal Syndrome

Subclavian steal syndrome (SSS) requires revascularization in symptomatic patients, with endovascular approaches generally preferred as first-line therapy due to lower complication rates despite similar long-term outcomes to surgical options. 1

Pathophysiology and Clinical Presentation

• SSS occurs when proximal subclavian artery stenosis or occlusion causes retrograde blood flow in the ipsilateral vertebral artery, leading to posterior cerebral circulatory insufficiency 1, 2
• Symptoms of vertebrobasilar insufficiency include lightheadedness, syncope, vertigo, ataxia, diplopia, and motor deficits, typically aggravated by upper-limb exercise 1, 3
• Upper extremity claudication with exercise-induced fatigue and pain in the affected arm is common 2, 4
• Coronary-subclavian steal syndrome can occur in patients with coronary bypass using the internal mammary artery, leading to myocardial ischemia during arm exercise 1, 5

Diagnostic Approach

• Bilateral arm blood pressure measurement is recommended for all patients with peripheral arterial disease, with a difference >15-20 mmHg suggesting subclavian artery stenosis 1, 4
• An inter-arm systolic blood pressure difference >25 mmHg doubles prevalence and independently predicts mortality 1, 4
• Detection of a periclavicular or infraclavicular bruit may indicate subclavian stenosis 2, 3
• Duplex ultrasonography can identify reversal of flow in the vertebral artery, with high-velocity flows (50% stenosis: peak systolic velocity ≥230 cm/s) 1, 6
• CT angiography or MR angiography of the aortic arch can definitively identify stenosis of the subclavian artery 1, 4

Management Algorithm

Step 1: Assess Symptom Severity

• Asymptomatic patients with asymmetrical upper-limb blood pressure or reversal of flow in a vertebral artery require no specific intervention beyond atherosclerosis risk factor management 1, 4
• Exception: Consider revascularization in asymptomatic patients if the ipsilateral internal mammary artery is required for myocardial revascularization 1, 4

Step 2: For Symptomatic Patients, Choose Revascularization Method

• Both endovascular and surgical options should be discussed case by case by a vascular team 1
• Endovascular revascularization may be considered over surgery due to lower complication rates, despite similar long-term outcomes 1

Endovascular Options:

• Balloon angioplasty, atherectomy, and stenting have high initial success rates (93-98%) 1
• Limitations: 6% of cases with total occlusion may preclude cannulation 1
• Median obstruction-free interval: 23 months, with 89% patency at 5 years 1
• 4-year patency rate: approximately 82% 1

Surgical Options:

• Carotid-subclavian bypass with prosthetic grafting is highly effective 1, 6
• Other options: carotid-axillary or axilloaxillary bypass, subclavian-carotid arterial transposition 1, 7
• Excellent long-term patency: 96-100% at 5 years 1
• Lower periprocedural complication rates compared to endovascular approaches (5.9% vs. 15.1%) 1

Special Considerations

• For patients with coronary-subclavian steal syndrome, revascularization is particularly important to prevent myocardial ischemia 5
• In patients with total occlusion of the subclavian artery, surgical bypass may be preferred as endovascular approaches may be unsuccessful 8
• For patients with concomitant carotid artery disease, the choice of surgical approach should be tailored accordingly 7

Follow-up

• After revascularization, patients should be followed up to allow early detection and treatment of impending late procedural failure 1
• Recurrent stenoses after endovascular treatment can often be managed with repeat percutaneous angioplasty 1