Coronary subclavian steal syndrome.

Inappropriate alterations in flow in the form of steal syndromes are a well recognised phenomenon. In the subclavian steal syndrome a proximal subclavian artery stenosis is responsible for reversal of flow in the vertebral artery and symptoms of vertebrobasilar ischaemia occur with arm movement. After internal mammary artery grafting to the coronary circulation, during coronary artery bypass surgery (CABG), coronary subclavian steal can occur. Retrograde flow occurs from the myocardium through the internal mammary graft to the subclavian artery secondary to a proximal subclavian stenosis. It is a rare but important cause of recurrent chest pain after coronary surgery.