Which of the following statement is true regarding subclavian steal syndrome

Subclavian steal syndrome - is a condition in which there is atherosclerotic occlusion in the first part of the subclavian artery. Reduction of blood flow in the subclavian artery beyond the stenosis leads to diminished blood flow to of arm vessels. This leads -to the formation of the collateral vessel from the vertebral artery which serves as a source of blood flow to the arm. There will be a reversal in the direction of blood flow in the vertebral artery, as the pressure in the vessels of the arm is low.