Surgical treatment of coronary subclavian steal syndrome

Area of Science:

• Cardiovascular Surgery
• Vascular Surgery
• Interventional Cardiology

Background:

• The internal mammary artery (IMA) is the preferred arterial conduit for coronary artery bypass grafting (CABG).
• Coronary artery disease (CAD) can coexist with atherosclerotic disease in other major arteries, including the subclavian artery.
• Left internal mammary artery (LIMA) grafts are widely used due to their superior long-term patency rates.

Observation:

• Proximal stenosis of the left subclavian artery (LSA) can occur in patients undergoing cardiac revascularization.
• A patent LIMA graft provides an alternative pathway for blood flow from the aorta to the coronary circulation.
• Symptoms of myocardial ischemia may arise despite patent coronary grafts.

Findings:

• Left subclavian artery stenosis can lead to a 'coronary steal syndrome' phenomenon.
• This steal occurs when the LIMA graft preferentially perfuses the coronary arteries, drawing blood flow away from the vertebrobasilar system via the LSA.
• The pressure gradient across the LSA stenosis exacerbates this steal, leading to reduced antegrade flow in the LSA and potential arm ischemia, while causing myocardial ischemia due to altered LIMA flow dynamics.

Implications:

• Recognition of LSA stenosis is critical in patients presenting with recurrent angina after CABG with LIMA.
• Non-invasive imaging or angiography may be required to diagnose LSA stenosis in this context.
• Management strategies may include angioplasty or surgical repair of the LSA stenosis to restore adequate flow and resolve the steal phenomenon.