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In medicine, subclavian steal syndrome (SSS), also subclavian steal phenomenon and subclavian steal steno-occlusive disease, is a constellation of signs and symptoms that arise from retrograde (reversed) vertebral artery (blood) flow due to a proximal subclavian artery stenosis (narrowing) and/or occlusion.
Pathophysiology
SSS is a consequence of a redunancy in the circulation of the brainKlingelhofer J, Conrad B, Benecke R, Frank B. Transcranial Doppler ultrasonography of carotid-basilar collateral circulation in subclavian steal. Stroke. 1988 Aug;19(8):1036-42. PMID 3041649.Lord RS, Adar R, Stein RL. Contribution of the circle of Willis to the subclavian steal syndrome. Circulation. 1969 Dec;40(6):871-8. PMID 5377222. and hemodynamics (the physics of blood flow).
SSS results when the short low resistance path (along the subclavian artery) becomes a high resistance path (due to narrowing) and blood flows around the narrowing via the arteries that supply the brain (left and right vertebral artery, left and right internal carotid artery). The blood flow from the brain to the upper limb in SSS is considered to be stolen as it is blood flow the brain must do without.
Hemodynamics
Blood, like electrical current, flows a long the path of least resistance. If blood is presented with two paths a short one that is very narrow (with a high overall resistance) and a long one that is wide (with a low overall resistance) it will take the long and wide path (the one with the lower resistance).Vascular anatomy
The blood vessels supplying the brain arise from the vertebral arteries and internal carotid arteries and are connected to one another by communicating vessels that form a circle (known as the cerebral arterial circle).Path of the blood (normal versus SSS)
Normally, blood flow from the aorta into the subclavian artery and then some of that blood leaves via the vertebral artery to supply the brain.In SSS a reduced quantity of blood flows through the proximal subclavian artery. As a result, blood travels up one of the other blood vessels to the brain (the other vertebral or the carotids) goes around the cerebral arterial circle and via the (ipsilateral) vertebral artery to the subclavian (with the proximal blockage) and feeds blood to the distal subclavian artery (which supplies the upper limb and shoulder).
Etiology
Signs and symptoms
- Presyncope (sensation that one is about to faint)
- Syncope (fainting)
- Neurologic deficits
- Blood pressure differential between the arms
Associated with other stigma to vascular disease (e.g. vascular insufficency ulcers of the foot).
Differential diagnosis
Diagnostic tests
Treatment
References
External links
- Subclavian Steal Syndrome - emedicine.com
"Subclavian steal syndrome"