From the Guidelines
Subclavian steal syndrome in its early stages typically presents with subtle neurological symptoms that occur during arm exercise on the affected side, including dizziness, vertigo, visual disturbances, and syncope, which are indicative of blood being "stolen" from the vertebrobasilar circulation to supply the arm when demand increases during activity 1.
Clinical Signs
The clinical signs of subclavian steal syndrome include:
- A difference in blood pressure measurements between arms (typically >25 mmHg lower in the affected arm) 1
- Diminished or absent radial pulse on the affected side
- Occasionally a supraclavicular bruit that may be heard on auscultation
- Symptoms of vertebrobasilar insufficiency such as diplopia, dysarthria, and ataxia that worsen with arm exercise These manifestations result from retrograde flow in the vertebral artery as blood is diverted to the subclavian artery distal to the stenosis.
Diagnosis
The diagnosis of subclavian steal syndrome should be considered in patients with posterior cerebral circulatory insufficiency aggravated by upper-limb exercise, and can be confirmed by vascular imaging studies such as duplex ultrasonography, which can identify reversal of flow in a vertebral artery, or CTA or MRA of the aortic arch, which can identify stenosis of the subclavian artery 1.
Management
Asymptomatic patients with subclavian steal syndrome require no specific intervention other than strategies directed at the secondary prevention of ischemic events related to systemic atherosclerosis, while symptomatic patients should be considered for subclavian revascularization with endovascular or surgical techniques 1.
From the Research
Clinical Signs of Subclavian Steal Syndrome
The clinical signs of subclavian steal syndrome can vary, but some common symptoms include:
- Syncope and left upper arm weakness, suggesting ischemia of the cerebral and left upper arm circulation 2
- Paroxysmal vertigo, drop attacks, and/or arm claudication due to compromised vertebrobasilar and brachial blood flows 3
- Pain and numbness in the left upper arm when raising the arm above the head 4
- Discrepant arm blood pressures or a diminished or weakened radial pulse unilaterally 5
- Vertebral-basilar symptoms or arm ischemia 5
Diagnostic Approaches
Diagnostic approaches for subclavian steal syndrome include:
- Volume-plethysmographic blood pressure measurements to clarify differences between upper arm blood pressures 2
- High-resolution Doppler instrument to reveal retrograde vertebral artery waveform 2
- Aortography to demonstrate proximal subclavian artery occlusion 2
- Doppler ultrasound as a useful screening tool, with diagnosis confirmed by CT or MR angiography 3
- Angiography to reveal retrograde perfusion of the vertebral artery and occlusion of the subclavian artery 4
Treatment Options
Treatment options for subclavian steal syndrome include:
- Conservative treatment as the initial best therapy, with surgery reserved for refractory symptomatic cases 3
- Percutaneous angioplasty and stenting as a widely favored surgical approach 3, 6
- Stent implantation via a femoral approach using the latest equipment 2
- Angioplasty and stenting to relieve symptoms and improve blood flow 4, 6