Head and Neck
Which of the following statements is true regarding subclavian steal syndrome (AIPG 2011)
|A||Reversal of blood flow in ipsilateral vertebral artery|
|B||Reversal of blood flow in the contralateral carotid artery|
|C||Reversal of blood flow in contralateral vertebral artery|
|D||Bilateral reversal of blood flow in the vertebral arteries|
1. Subclavian steal steno-occlusive disease, is a constellation of signs and symptoms that arise from retrograde (reversed) vertebral artery (blood) flow or retrograde internal thoracic artery flow due to a proximal subclavian artery stenosis (narrowing) and/or occlusion.
2. 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.
3. 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.
4. 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 (of Willis) 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).